ABSTRACT BOOK VerMidi XIX

ENS Amphithéâtre Mérieux

Friday Jan 8th, 2016 VERMIDI XIX PROGRAM

9:30 - 10:00 Welcome Breakfast 10:00 - 10:45 Keynote Lecture: Mario De Bono Into the unknome: high throughput genetics and novel neural functions 10:45 - 12:00 Session 1

10:45 - 11:05 Marie Gendrel (Columbia University, New York) The GABAergic system: not a closed chapter. 11:05 - 11:25 Adeline Mergoud Dit Lamarche (INMG, Lyon) Identification of a transcription factor as determinant of muscle aging in C. elegans 11:25 - 11:45 Sonia El Mouridi (INMG, Lyon) A streamlined protocol to facilitate CRISPR/Cas9 genome engineering using a highly efciency sgRNA and an easily selectable phenotype 11:45 - 12:00 A word from our sponsors Hybrigenics – GATC Biotech – Bioaxial

12:00 - 15:00 Lunch / Poster Session

15:00 - 16:20 Session 2

15:00 - 15:20 Flore Beurton (LBMC, Lyon) Characterization of the SET1/MLL complex in C. elegans 15:20 - 15:40 Le He (CIML, ) Dissecting a worm killer 15:40 - 16:00 Clara Tafoni (CIML, Marseille) Host response to fungal infection and wounding in C. elegans epidermis 16:00 - 16:20 Thanh Vuong-Brender (UPMC, ) Composition, organization and mechanical contribution of C. elegans embryonic sheath to embryonic integrity and elongation 16:20 - 17:00 Cofee break

17:00 - 18:20 Session 3 17:00 - 17:20 Mathieu Baritaud (INMG, Lyon) The anti-apoptotic CED-9/Bcl-2 protein protects against muscle degeneration in Caenorhabditis elegans models for muscular dystrophies 17:20 - 17:40 Fabrice Besnard (IBENS, Paris) Mapping and identifying mutations causing rapid evolution in a cell fate using Mutation Accumulation lines in C. elegans and C. briggsae 17:40 - 18:00 Lisa Martino (IJM, Paris) Polo-like kinase is required for nuclear envelope breakdown in early C. elegans embryo 18:00 - 18:20 Jane Deuve (UPMC, Paris) Control of autophagy during worm development via an intronic region

18:30 Happy Hour

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Métro B Stade de Gerland SPONSORS Table of contents

The GABAergic system: not a closed chapter., Marie Gendrel [et al.] ...... 5

Identification of a transcription factor as determinant of muscle aging in Caenorhabditis elegans, Adeline Mergoud Dit Lamarche [et al.] ...... 6

A streamlined protocol to facilitate CRISPR/Cas9 genome engineering using a highly eciency sgRNA and an easily selectable phenotype, Claire Lecroisey [et al.] ...... 7

A word from our sponsors ...... 8

Characterization of the SET1/MLL complex in C. elegans, Flore Beurton [et al.] .... 9

Dissecting a worm killer, Le He [et al.] ...... 10

Host response to fungal infection and wounding in C. elegans epidermis, Clara Ta↵oni [et al.] ...... 11

Composition, organization and mechanical contribution of C. elegans embryonic sheath to embryonic integrity and elongation, Thanh Vuong-Brender [et al.] ...... 12

The anti-apoptotic CED-9/Bcl-2 protein protects against muscle degeneration in Caenorhab- ditis elegans models for muscular dystrophies, Mathieu Baritaud [et al.] ...... 13

Mapping and identifying mutations causing rapid evolution in a cell fate using Mutation Accumulation lines in C. elegans and C. briggsae., Fabrice Besnard [et al.] ...... 14

Polo-like kinase is required for nuclear envelope breakdown in early C. elegans em- bryo, Lisa Martino [et al.] ...... 15

Control of autophagy during worm development via an intronic region, Jane Deuve [et al.] 16

Cell-to-cell communication modulates the immune response in Caenorhabditis elegans, Song Hua Lee [et al.] ...... 18

C.elegans genomic platform of Marseille-Luminy, J´erˆomeBelougne [et al.] ...... 19

1 Purine metabolism a↵ects post-embryonic development, germline proliferation and mus- cle structure in C. elegans, Roxane Marsac [et al.] ...... 20

Regulatory network in C. elegans innate immunity, Nishant Thakur [et al.] ...... 21

Targeted multicopy transgene integration in C. elegans, Iskra Katic [et al.] ...... 22

Comparison of ivermectin and moxidectin resistance profiles in the nematode Caenorhab- ditis elegans, C´ecile Menez [et al.] ...... 23

Characterization of nematode-infecting microsporidia and natural variation in sensitivity of Caenorhabditis nematodes to microsporidia, Gaotian Zhang [et al.] ...... 24

Quantitative Analysis of the Polarization mechanism of a field of Neuronal Precursors in C. elegans, Shilpa Kaur [et al.] ...... 25

Analysis of chromatin factors involved in the initiation and maintenance of neuronal di↵erentiation programs, Guillaume Bordet [et al.] ...... 26

Host pathogen interactions in C. elegans, Jean-Christophe Lone [et al.] ...... 27

Cellular innovations at the origin of pseudogamy in nematodes, Manon Grosmaire [et al.] 28

How cellular plasticity promoted and controlled an organism?, Thomas Le Gal [et al.] . 29

The SET-2/SET1 histone H3K4 methyltransferase maintains genome stability in the Caenorhabditis elegans germline, Marion Herbette [et al.] ...... 30

Mechanosensing in C. elegans embryogenesis: Hunting for a putative mechanosensor, Shashi Kumar Suman [et al.] ...... 31

Identification of novel regulators of GABAergic synaptogenesis in the nematode Caenorhab- ditis elegans., Marine Gueydan [et al.] ...... 32

Micro-movements of the mitotic spindle poles reveal cell division mechanics., Benjamin Mercat [et al.] ...... 33

The C. elegans K cell as a new model to study cellular potential, asymmetric cell division and cell type conversion, Christelle Gally [et al.] ...... 34

DRP-1, AIF and mTOR : a link between mitochondria morphology and muscle degen- eration in C. elegans ?, Charlotte Scholtes [et al.] ...... 35

Is unc-70 /-spectrin a functional regulator of the neuronal potassium channel unc- 58 ?, Philippe Tardy [et al.] ...... 36

The role of sel-10 in transdi↵erentiation, C´ecile Delance [et al.] ...... 37

2 Cryptic evolution behind a conserved asymmetric embryonic division in nematodes, Marie Delattre [et al.] ...... 38

List of participants 38

Author Index 42

3 KEYNOTE LECTURE

Into the unknome: high throughput genetics and novel neural functions

Mario De Bono

MRC Laboratory of Molecular Biology, Cambridge, UK.

4 The GABAergic system: not a closed chapter.

1,2 2 1,2 Marie Gendrel ⇤ , Emily Atlas , Oliver Hobert†

1 Howard Hughes Medical Institute (HHMI) – New York, United States 2 Columbia University, Department of Biochemistry and Molecular Biophysics – New York, United States

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the vertebrate brain, and dysfunction of GABAergic neurons can have profound pathological implications. In C. elegans, based on promoter fusion analysis, 26 neurons are known to express conserved GABAergic ter- minal di↵erentiation genes, such as the enzyme-producing GABA (GAD/unc-25 ), the GABA-specific vesicular transporter (VGAT/unc-47 ) and the protein that targets VGAT to the synaptic membrane (a LAMP-like protein/unc-46 ). Twenty-five of these worm GABAergic neurons are motoneurons and are involved in (i) head movements (4 RMEs), (ii) defecation (AVL and DVB), (iii) locomotion (19 D-type). Only one neuron, RIS, is an interneuron, like the dominant type of GABA neurons in vertebrates. Yet, in addition to the 26 classic GABA neurons, we detected by immunostaining GABA in the head mesodermal cell (hmc), ALA, RIBL/R and four other pairs of neurons whose identification is still in progress. Using fosmid recombinering and CRISPR technology, we are mapping where the GABAer- gic terminal di↵erentiation genes are expressed in order to get a more comprehensive picture of the GABAergic system.

In parallel, we have a better understanding of how the di↵erentiation of the 26 classic GABAergic neurons is controlled. As published, it is known that UNC-30, a Pitx2 ortholog, is required for ex- pression of GABA terminal di↵erentiation genes in the D-type neurons. It is currently unknown what the terminal selectors for the other GABAergic neurons are. Through a candidate gene approach, we confirmed with anti-GABA immunostaining that LIM-6 -a LIM homeobox transcription factor- controls RIS, AVL and DVB fate. In addition, we generated a null allele of nhr-67 –a Tailless/TLX ortholog– and using anti-GABA immunostaining and marker analysis, we concluded that NHR-67 is involved in RIS, AVL and RMEs terminal di↵erentiation, suggesting that NHR-67 and LIM-6 act together to control RIS and AVL GABAergic fate. We also confirmed that CEH-10 is involved in RME terminal di↵erentiation. Moreover, after an EMS mutagenenesis screen, we found that TAB-1, a homeodomain transcription factor, is involved in RMEL/R GABAergic fate, suggesting that NHR-67, CEH-10 and TAB-1 work together to control RME fate. In parallel, we are currently investigating in DVB fate the role of EGL-38 - a Pax2/5/8 family member - and in D-type fate the role of ELT-1 – a GATA like transcription factor. Together, these results will give us an updated picture of GABA neuron identification and development.

⇤Speaker †Corresponding author: [email protected]

5 Identification of a transcription factor as determinant of muscle aging in Caenorhabditis elegans

1 1 1 Adeline Mergoud Dit Lamarche ⇤ , Laurent Molin , Kathrin Gieseler , Jean-Louis Bessereau 1, Florence Solari 1

1 Centre de g´en´etique et de physiologie mol´eculaire et cellulaire (CGphiMC) – CNRS : UMR5534, Universit´e Claude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Bˆatiment Gregor Mendel 16 rue Rapha¨elDubois 69622 VILLEURBANNE CEDEX, France

Aging is accompanied by a progressive loss of muscle mass and function termed sarcopenia. In human, sarcopenia is responsible for a decrease in mobility, leading to a reduction in the quality of life. Epidemiological studies further suggest that skeletal muscle aging is also a risk factor for the devel- opment of several age-related diseases such as diabetes, cancer, Alzheimer’s disease, and Parkinson’s disease. Several cell autonomous mechanisms have been proposed to be involved in muscle aging including mi- tochondria default [1], apoptosis [2] and alteration of muscle protein turnover [3]. However, those data have been essentially obtained in models of experimentally induced muscle atrophy. Thus the question of their importance and kinetic in the context of physiological aging remains unanswered. We are using C. elegans to identify genetic pathways involved in muscle aging. Previous studies have shown that worms exhibit loss of mobility [4], myosin filament disorganization and change in muscle nuclei shape with age [5]. More recently, the Xu laboratory reported a functional decline of motor neurons that precedes alteration of muscle contraction [6]. However those studies did not allowed to identify genuine muscle biomarker of sarcopenia that could be used to screen for genetic modifiers of sarcopenia. For this purpose, we first aimed to characterize the time course of cellular and molecular changes that take place during muscle aging.

We have shown that muscle aging is firstly characterized by a decrease in the expression of some but not all muscle genes, followed by a change in mitochondria morphology and an impairment of muscular proteostasis. As the decrease of muscle genes expression is the earliest event, we hypothesized that it may play a causal role in sarcopenia. Further genetic, cellular and molecular investigations allowed us to identify a transcription factor, which modulates di↵erent biomarkers of muscle aging and which function may be conserved in mammals.

1. Romanello V et al. EMBO J. 2010;29: 1774–1785. doi:10.1038/emboj.2010.60 2. Marzetti E et al. Gerontology. 2012;58: 99–106. doi:10.1159/000330064 3. Masiero E et al. Autophagy. 2010;6: 307–309. 4. Huang C et al. Proc Natl Acad Sci U S A. 2004;101: 8084–8089. doi:10.1073/pnas.0400848101 5. Herndon LA et al. Nature. 2002;419: 808–814. doi:10.1038/nature01135 6. Liu J et al. Cell Metab. 2013;18. doi:10.1016/j.cmet.2013.08.007

⇤Speaker

6 A streamlined protocol to facilitate CRISPR/Cas9 genome engineering using a highly eciency sgRNA and an easily selectable phenotype

1 1 1 1 Claire Lecroisey , Sonia El Mouridi ⇤ , Philippe Tardy , Melissa Zouak , 1 Thomas Boulin†

1 Institut NeuroMyoG`ene (INMG) – Universit´eClaude Bernard-Lyon I - UCBL (FRANCE) – 8 RUE RAPHAEL DUBOIS, 69100 Villeurbanne, France

Current CRISPR/Cas9 genome engineering strategies enable the directed modification of the en- tire C. elegans genome to introduce point mutations, generate knock-out mutants and insert coding sequences for epitope or fluorescent tags. Three practical aspects can complicate CRISPR experiments. First, the eciency of any given sgRNA (single guide RNA) cannot be reliably predicted. Second, the detection of animals the genome of which has been modified can be very challenging or time consuming in the absence of a clearly visible or selectable phenotype. Third, the sgRNA target site must be ”inactivated” following CRISPR-directed editing to avoid further double-strand break events. This often requires the introduction of silent mutations (e.g. in the Protospacer Adjacent Motif, PAM).

We describe here a strategy that attempts to address and circumvent these complications. First, we use CRISPR/Cas9 editing to transplant the protospacer sequence of a highly ecient C. elegans sgRNA into a gene or close to a genomic region of interest. We have chosen an sgRNA targeting dpy-10 gene (Arribere et al. 2014) because (i) it generates genome edits at comparatively high frequency and (ii) because F1 progeny carrying genome edits can be easily identified based on dominant phenotypes (Dpy or Dpy/Rol) caused by the dpy-10(cn64) mutation.

Next, we demonstrate that the heterologous site (aka. d10 site) can be cleaved at the same time as the dpy-10 gene. Therefore, injected P0 animals and F1 progeny in which CRISPR events have occurred can be easily selected based on the dominant dpy-10 phenotypes (”marked” F1 worms). This drastically reduces the number of animals to be tested by PCR, visual inspection or phenotypic analysis.

Finally, using the d10 -engineered strain, we are no longer required to introduce mutations in endoge- nous PAM sites or otherwise disrupt the genome sequence close to the targeted region when inserting point mutations or integrating specific DNA sequences.

So far, we have been able to reliably engineer four di↵erent loci and rapidly introduce multiple flu- orescent genes with minimal work. Using our strategy, gene edits are identified in 2 to 8.5 % of marked F1 worms. We have also used the same d10 -engineered strains to generate large and precise deletions in two genes.

⇤Speaker †Corresponding author: [email protected]

7 A word from our sponsors

8 Characterization of the SET1/MLL complex in C. elegans

1 1 1 Flore Beurton⇤ , C´ecile Bedet ⇤ , Matthieu Caron ⇤ , Francesca Palladino ⇤ † 1

1 Laboratory of Molecular and Cellular Biology – Ecole´ Normale Sup´erieure - Lyon – 46 all´ee d’italie 69007 Lyon, France

Methylation of histone H3 Lys4 (H3K4me) is associated with active transcription in all species, and is catalyzed by highly conserved multiprotein complexes known as Compass in yeast or SET1/MLL in mammals. Work from several labs using both yeast and mammalian cells has led to a detailed de- scription of the SET1/MLL complexes. Biochemical analysis has shown that the H3K4 HMT activity of SET1/MLL proteins relies on protein-protein interactions within large multisubunit complexes that include three core components: RbBP5, Ash2L, and WDR5. However, it remains unclear how the composition and specificity of these complexes varies between cell types and during development. We then decided to study the function of individual subunits of the complex in a developmental context. We have previously shown that SET-2, the sole SET1 homologue in C. elegans, and ASH-2, another member of the SET1/MLL complex play di↵erent roles in H3K4me during development. We have also shown an interaction between SET-2 and WDR-5.1 in embryos, but the full composition of the H3K4 HMT complex in vivo is unknown. In order to better understand the regulation of H3K4me, we have decided to develop a proteomic approach to identify SET-2/WDR-5.1 molecular partners. Preliminary attempts to immunoprecipitate a functional SET-2::HA tagged protein generated by CRISPR- Cas9 have failed. As an alternative strategy, we used animals expressing a WDR-5.1::HA protein to immunoprecipitate the complex in embryos extracts and its composition will be analyzed by mass spectrometry. Interesting partners will then be characterized using both genetic and biochemical ap- proaches.

⇤Speaker †Corresponding author: [email protected]

9 Dissecting a worm killer

1 2 1 2 Le He ⇤ , Kevin Lebrigand , Nathalie Pujol , Pascal Barbry , Jonathan 1 Ewbank†

1 Centre d’Immunologie de Marseille - Luminy (CIML) – Universit´ede la M´editerran´ee- Aix-Marseille II, CNRS : UMR7280, Inserm : U1104 – Parc scientifique et technologique de Luminy - 163, avenue de Luminy - Case 906 - 13288 Marseille cedex 09, France 2 Institut de pharmacologie mol´eculaire et cellulaire (IPMC) – CNRS : UMR7275, Universit´eNice Sophia Antipolis (UNS) – CNRS-IPMC 660 Route des lucioles 06560 VALBONNE, France

We have studied intensively the infection of C. elegans by Drechmeria coniospora (see Labed & Pujol (2012), Journal of Invasive Fungal Infections). We have recently initiated a project to dissect the molecular and cellular basis of D. coniospora’s capacity to infect worms and resist host immunity. As a first step, in collaboration with the Genoscope, we undertook the sequencing of the D. coniospora genome. Combining di↵erent data, we have assembled a draft genome of 33 Mb on 9 chromosomes, and predicted 8,000 coding genes. On the basis of their sequence, more than half are associated with Pfam & GO terms.

With the genome sequence in hand, we are taking 2 approaches to identify virulence genes: com- parative genomics and biochemistry: Sequence analyses revealed the presence of many genes potentially encoding virulence factors. As an ex- ample, the gene g3895, corresponding to a Saposin A type domain (PF02199) with a secretion peptide, was clearly acquired by horizontal gene transfer. Saposins are host defence proteins. In vertebrates, they are synthesized as proproteins, with the active saposin B domain inhibited by the regulatory saposin A domain. There are 26 saposin B domain containing proteins in C. elegans. We speculate that Drechmeria’s Saposin A protein may act as an inhibitor of nematode saposin B-containing proteins and thus interfere directly with host defense. A reporter strain showed that g3895 is strongly express on spores before attachment to the worm’s cuticle and on hyphae as they exit infected worms. Further study is in process. To identify proteins secreted from the fungal pathogen into the host epidermal cells, a biotin-streptavidin based method was used. By locally expressing ascorbate peroxidase in the worm epidermis (using strains generously provided by Aaron Reinke and Emily Troemel), only the proteins present become biotinylated. The biotinylated proteins have been purified with streptavidin beads and subject to mass spectrometry analysis. Preliminary results have allowed the identification of several fungal proteins, potentially secreted into the worm cells during infection. We now plan to characterize the function of these putative virulence factors.

⇤Speaker †Corresponding author: [email protected]

10 Host response to fungal infection and wounding in C. elegans epidermis

1 2 1 3 Clara Ta↵oni ⇤ , Jonathan Ewbank , Didier Marguet , Nathalie Pujol†

1 Centre d’Immunologie de Marseille - Luminy (CIML) – Universit´ede la M´editerran´ee- Aix-Marseille II, CNRS : UMR7280, Inserm : U1104 – Parc scientifique et technologique de Luminy - 163, avenue de Luminy - Case 906 - 13288 Marseille cedex 09, France 2 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universit´e- AMU : UM2, Inserm, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France 3 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universit´e- AMU : UM2, Inserm : U1104, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France

Sterile wounding or infection of Caenorhabditis elegans by the fungus D. coniospora leads to a rapid increase in the transcription of antimicrobial peptide (AMP) genes in the epidermis. Performing several genetic screens, we have previously identified many of the players involved in this innate immune re- sponse 1. Recently, we have shown that the GPCR DCAR-1 and its ligand HPLA, a tyrosine derivative can trigger this response 2, through the p38 MAPK pathway which in turn activates the STAT-like transcription factor STA-2 and induces AMP expression. Because genetic inactivation of vesicle traf- ficking abrogates immune signalling 3, we are interested in monitoring the subcellular localization and dynamics of the known signalling proteins upon damage and in studying their role in modulating the host immune response. Using a knock-in strain where the GPCR DCAR-1 is tagged with tomato or with GFP, we observed an apical signal on the epidermal syncytium which is rapidly relocalized upon wounding. We are now characterizing this recruitment together with the behavior of other signalling proteins upon infection and wounding.

In a recent study it was proposed that the STAT-like TF STA-2 is physically associated with hemidesmo- somes, which anchor the cuticle and the muscle to the epidermis and could act as mechanosensor. Re- moving one apical component of the hemidesmosomes can release STA-2 and activate AMP expression in the epidermis 4. We are investigating if this mechanosensory pathway could act in parallel to the DAMP/HPLA pathway to sense an infection in the worm.

Labed, S. & Pujol, N. The Journal of Invasive Fungal Infection 5, 110-117 (2011). Zugasti, O. et al. Nature Immunology 15, 833-838 (2014). Dierking, K. et al. Cell Host Microbe 9, 425-435 (2011). Zhang, Y. et al. Immunity 42, 309-320 (2015).

⇤Speaker †Corresponding author: [email protected]

11 Composition, organization and mechanical contribution of C. elegans embryonic sheath to embryonic integrity and elongation

1 1 Thanh Vuong-Brender ⇤† , Michel Labouesse‡

1 Laboratoire de Biologie du D´eveloppement (LBD) – CNRS : UMR7622, Universit´ePierre et Marie Curie (UPMC) - Paris VI – bat. C-30, 7 Etage, bte.24 9 Quai Saint-Bernard 75252 PARIS CEDEX 05, France

During morphogenesis, the remodeling of apical epidermal structures like cytoskeleton and junc- tions has been well characterized. In contrast, little is known about the role and the remodeling of apical extracellular matrix. The embryonic sheath wrapping around C. elegans embryo has been pro- posed to be the force-transmitting component during its elongation (Priess and Hirsch 1986). However, the composition of this extracellular layer is largely unknown and how it transmits actomyosin forces is poorly understood. In an RNAi screen for transmembrane and secreted proteins a↵ecting embry- onic morphogenesis, we identified NOAH-1 and NOAH-2, two ZP (Zona Pellucida)-domain containing proteins essential for the embryos to complete elongation. We built endogenous reporters of these proteins using CRISPR-CAS9 technique. Their localization at the apical epidermal surface and the in the extra-embryonic space suggested that they are embryonic sheath components. They showed a remarkable reorganization during late phase of the embryonic elongation (after 2-fold embryo stage) and this remodeling seemed to be promoted by muscle contractions. We found that these two proteins, together with other putative extracellular matrix proteins SYM-1, LET-4 and FBN-1, contribute to the embryonic integrity after 2-fold stage. To assess mechanical properties and tension on the embryonic sheath during elongation, we used laser nano-ablation. The results showed that this layer is either more elastic or less viscous than the actin cortex. In lateral epidermal cells, the recoil of the sheath after ablation was dependent on actin cortex, implying that the sheath relays actomyosin forces. Our studies help to shed light on the importance of apical extracellular matrix and its interaction with other tissues during morphogenesis.

Priess, J. R. and D. I. Hirsh (1986). ”Caenorhabditis elegans morphogenesis: the role of the cytoskeleton in elongation of the embryo.” Dev Biol 117(1): 156-173.

⇤Speaker †Corresponding author: [email protected] ‡Corresponding author: [email protected]

12 The anti-apoptotic CED-9/Bcl-2 protein protects against muscle degeneration in Caenorhabditis elegans models for muscular dystrophies

1 1 1 Mathieu Baritaud ⇤ , Marie-Christine Mariol , Edwige Martin , Kathrin 1 Gieseler†

1 Centre de g´en´etique et de physiologie mol´eculaire et cellulaire (CGphiMC) – CNRS : UMR5534, Universit´e Claude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Bˆatiment Gregor Mendel 16 rue Rapha¨elDubois 69622 VILLEURBANNE CEDEX, France

Muscular dystrophies are characterized by muscle weakness and degeneration induced by genetic mutations a↵ecting muscle structure or signaling components. The subcellular mechanisms of muscular dystrophies are poorly understood and the development of treatments is challenging, in part due to great variety of primary genetic defects. Using di↵erent Caenorhabditis elegans models that mimic human muscular dystrophies such as Duchenne and Becker dystrophies, Limb-Girdle, Emery- Dreifuss or congenital muscular dystrophy, we found that a gain of function mutation of the anti-apoptotic protein CED-9, ortholog of mammalian B cell lym- phoma 2 (Bcl-2), strongly reduced muscle degeneration.

To investigate the molecular pathways, we analyzed the impact of mutations a↵ecting keys e↵ectors of programmed cell death (PCD) mechanisms such as CED-3/caspase-3, CED-4/Apaf-1, CED-9/Bcl-2, CED-13 and EGL-1 (two orthologs of pro-apoptotic Bcl-2 protein family) on muscle degeneration in the Duchenne Muscular Dystrophy (DMD) C. elegans model. We evaluated di↵erent features of muscle cell death : destruction of actin filament network, nuclei loss, mitochondrial stress by measuring ROS production with Hyper transgene; and the state of mitochondrial network. Using CRISPR mediated genome engineering we currently determine domains of protein interactions between CED-9 and the di↵erent PCD e↵ectors so as to reveal new PCD actors involved in muscle degeneration through the investigation of CED-9 partners.

Finally, by deciphering the role of the PCD machinery and the anti-apoptotic CED-9 protein in di↵er- ent C. elegans models for muscular dystrophies, we aim at identifying common molecular pathways to reduce, stop or reverse muscle degeneration in muscular dystrophies.

⇤Speaker †Corresponding author: [email protected]

13 Mapping and identifying mutations causing rapid evolution in a cell fate using Mutation Accumulation lines in C. elegans and C. briggsae.

1 1 Fabrice Besnard ⇤ , Marie-Anne Felix

1 Institut de Biologie de l’Ecole Normale Sup´erieure (IBENS) – Institut de Biologie de l’Ecole Normale Sup´erieure – 46, rue d’Ulm 75005 PARIS, France

How mutations a↵ect phenotypes is a crucial question in both developmental biology and evolu- tion. In Caenorhabditis nematodes, we use the paradigmatic model of vulva precursor cells (VPC) development to address why di↵erent cell lineages do not show equal robustness to mutations. Indeed, our lab recently showed that one VPC, P3.p, has a much higher mutational variance than the five other vulval precursors (Braendle, Baer & F´elix, PLoS Gen. 2010), by analyzing phenotypes of a set of Mutation accumulation Lines (MALs) of C. elegans and C. briggsae. In wild-type worms, P3.p already stands out by having a stochastic cell fate: it can either divide once or fuse directly with the epidermis without dividing. In an isogenic population of worms, the division frequency of P3.p is reproducible for a genotype, in a given environment. In MALs, P3.p division frequency is the fastest evolving vulva trait. Interestingly, this result mirrors the real evolution observed within the Caenorhabdtitis genus. Although the gene regulatory network controlling vulva cell specification is well-known, we cannot ex- plain such high mutational variance of P3.p: is it due to hotspots of mutations specifically involved in P3.p fate determination? To a specific genetic architecture? Or to a particular developmental con- text? We thus selected 6 MALs produced by 250-generations of single-worm bottlenecks (two in C. briggsae, four in C. elegans) displaying marked evolution of P3.p division frequency and we seek to identify the molecular nature of the mutations causing this evolution. By whole-genome re-sequencing, we thoroughly analyzed de novo mutations in each line. First, we found interesting features such as occurrences of large (several kbp) deletions or di↵erences between C. elegans and C. briggsae muta- tion rates, in line with di↵erences in mutational variance measured a few years ago between those two species. Second, we mapped and identify candidate mutations in 5 lines by using a strategy based on serial parallel backcrosses and direct genotyping by pyrosequencing. To our knowledge, this is the first report of the identification of mutations responsible for the evolution of a phenotype in MALs. We are currently validating those mutations, especially by reproducing the exact mutation by CRISPR-Cas9 genome editing. The diversity of the genes a↵ected (members of the Wnt signaling pathway; of the transcriptional repressor mediator complex, of translational activation and genes of unknown functions) strongly suggests that the high mutational variance of P3.p is due to a wide mutational target size. These results also broaden our view of the genes involved in the fine-tuning of VPC cell fate.

⇤Speaker

14 Polo-like kinase is required for nuclear envelope breakdown in early C. elegans embryo

1 1 Lisa Martino ⇤ , Lionel Pintard

1 Institut Jacques Monod (IJM) – UMR7592, Paris-Diderot University - CNRS – 15 rue h´el`ene brion, 75013 PARIS, France

⇤Speaker

15 Control of autophagy during worm development via an intronic region

1 1 1 1 Jane Deuve ⇤ , Jorge Merlet , Charl`ene Perrois , Sara Al Rawi , Vincent Galy 1

1 C. elegans Heredity and Development (CelHD) – Universit´eParis VI - Pierre et Marie Curie – UMR7622 - IBPS University Pierre and Marie Curie - CNRS - Paris- France, France

In C. elegans autophagy, the respective functions of the two actors LGG-1 and LGG-2 are starting to be unravelled. Despite the fact that LGG-2 (the C. elegans homolog of mammalian LC3) is thought to be secondary for autophagy to be achieved (the two reported null mutants have a normal development) we describe a new lgg-2 lethal mutant that sheds light on the importance of LGG-2. We have shown that in lgg-2 first intron stands a Caenorhabditis conserved DNA sequence crucial for controlling lgg-2 transcription in a tissue-dependant manner. In the mutant lacking this region, LGG-2 is abnormally up regulated in the muscle attachment structure, and the therefore up regulated autophagy is correlated with a sleeping bag phenotype, the mutant worms being unable to escape their molt. We propose a catalytic function for LGG-2, able to fine tune autophagy during normal development.

⇤Speaker

16 Poster session

17 P1 – Cell-to-cell communication modulates the immune response in Caenorhabditis elegans

1 1 1 1 Song Hua Lee ⇤ , Annie Boned , Shizue Omi , Jonathan Ewbank† , Nathalie 1 Pujol‡

1 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universit´e- AMU : UM2, Inserm : U1104, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France

The C. elegans epidermis is a powerful model for understanding the fundamental innate defence strategies of epithelial tissues. Upon invasion by the fungal pathogen Drechmeria coniospora or physical injury, C. elegans mounts an innate immune response, upregulating the expression of antimicrobial pep- tide genes in the epidermis (1). Increasing evidence suggests that cell-cell communication is essential to generate coordinated protective responses (reviewed in 2). For instance, Kawli and Tan demon- strated that neuroendocrine signals modulate the expression of intestinal defence genes through the daf-2/daf-16 insulin-signalling pathway (3), whilst neuronally produced TGF-ß regulates expression of antimicrobial peptides in the epidermis (4). The expression of one insulin-like peptide gene, ins-11, that encodes a DAF-2 antagonist (5) is induced upon D. coniospora infection (6). We have now found that infection induces ins-11 expression in the epidermis and that this is dependent on the p38 MAPK pathway. Through comparative genomic analyses, we have defined a list of D. coniospora infection- response genes that are potential targets of DAF-16 in the intestine. We are currently assaying these genes to determine whether their expression is dependent upon ins-11. Defining such genes will then allow us to take a genetic approach to dissect the mechanisms underlying cross-tissue signalling and to study how a master tissue is capable of sensing perturbations within its own cellular environment and subsequently mediating organism-wide protection on other tissues upon infection or physical wounding.

1. Pujol et al., Current Biology 18: 481-489, 2008 2. Ewbank and Pujol, Current Opinion in Immunology 38:1-7, 2016 3. Kawli and Tan, Nature Immunology 9: 1415-1424, 2008 4. Zugasti and Ewbank, Nature Immunology 10: 249-256, 2009 5. Kawano et al., Bioscience, Biotechnology and Biochemistry 70: 3084-3087, 2006 6. Engelmann et al., PLoS ONE 6(5): e19055, 2011

⇤Speaker †Corresponding author: [email protected] ‡Corresponding author: [email protected]

18 P2 – C.elegans genomic platform of Marseille-Luminy

1 2 J´erˆome Belougne ⇤† , C´eline Caillard⇤

1 Centre d’Immunologie de Marseille-Luminy (CIML) – Inserm : U1104 – Centre d’Immunologie de Marseille-Luminy Parc Scientifique Technologique de Luminy, Case 906, 13288 Marseille cedex 09, FRANCE, France 2 Centre d’Immunologie de Marseille-Luminy (CIML) – CNRS : UMR7280 – Centre d’Immunologie de Marseille-Luminy Parc Scientifique Technologique de Luminy, Case 906, 13288 Marseille cedex 09, FRANCE, France

Custom developments to satisfy user needs enable the C. elegans platform of Marseille-Luminy to implement specific solutions for high-throughput genetic and genomic studies. Based around the CO- PAS worm sorter, the platform is able to perform the cloning of small populations, from 96 to 96-wells plates, as well as large screens, such as genome-wide RNAi and F3 clonal screens (EMS). The platform was part of the NEMAGENETAG MOS Project, generating 55,000 Mos1 transposon insertion lines from several hundred thousand clonal lines cultured for 6 generations. It has carried out genome-wide RNAi screens based on the Ahringer & Vidal libraries (e.g. 140,000 samples analysed in a screen for genes involved in anti-fungal innate immunity).

Recently, we have associated our TECAN robot with a Leica DMS300 macroscope, together with dedicated software (produced in collaboration with Dominique Brandli, IBDM), and we are now able to perform automated lifespan monitoring on di↵erent strains of interest. In principal, we can monitor the survival of more than 100 strains at a time.

Lastly, in collaboration with Igor Ozerov, (CINaM), we are attempting to develop an alternative to the time-consuming micro-injection method for the generation of transgenic strains.

⇤Speaker †Corresponding author: [email protected]

19 P3 – Purine metabolism a↵ects post-embryonic development, germline proliferation and muscle structure in C. elegans

Roxane Marsac 1, Christelle Saint-Marc 1, Bertrand Daignan-Fornier 1, 1 Jos´e-Eduardo Gomes ⇤†

1 Institut de biochimie et g´en´etique cellulaires (IBGC) – CNRS : UMR5095, Universit´ede (Bordeaux, France) – 1 Rue Camille Saint-Saens 33077 BORDEAUX CEDEX, France

Living organisms regulate their metabolism in response to their own physiological status and to the surrounding environment. Biosynthetic pathways have been extensively characterized mostly in unicellular organisms, much less is known about the relationship between metabolism and other cellu- lar/organismal functions in metazoans (e.g. development, cell cycle, behavior). Purine biosynthesis is highly conserved from bacteria to humans, and deficiencies on specific enzymes of the pathway cause severe human diseases. We developed a C. elegans model to study pathologies associated with purine metabolism. We verified functional conservation of crucial enzymes ADSL, PPAT and ATIC in C. ele- gans, and performed a phenotypic analysis of mutants deficient for these enzymes. We observed defects on post embryonic development, germline proliferation, locomotion behavior, muscle structure, fertility and lifespan. For the most part these phenotypes are separable; our results indicate that accumulation of intermediate metabolites SAICAR or AICAR causes shortened life span (SAICAR), reduced fertil- ity and abnormal locomotion (AICAR). Deficiency in ADSL enzyme causes abnormal post-embryonic development, defects on muscle structure and hinders germline proliferation. Our work allowed to establish a workable basis to analyze purine metabolism in the animal model organism C. elegans.

⇤Speaker †Corresponding author: [email protected]

20 P4 – Regulatory network in C. elegans innate immunity

1 1 1 1 Nishant Thakur ⇤† , Maxime Bulle , Annie Boned , Shizue Omi , Nathalie 1 1 Pujol , Jonathan Ewbank‡

1 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universit´e- AMU : UM2, Inserm, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France

Our lab is working on innate immunity using the nematode C. elegans as a model host. Upon fungal infection C. elegans up-regulates the expression of many antimicrobial peptide (AMP) genes. These AMPs provide direct protection against pathogen attack. We are building an integrated gene regulatory network for C. elegans to represent the induction of these AMP genes upon infection. To achieve this, we integrate in-house and public data from various techniques, including genome-wide RNAi screens, RNA-seq, small RNA-seq (mainly miRNA) and Chip-seq. Firstly, to identify the key genes of the network, our lab carried out a genome wide RNAi screen and identified 360 RNAi clones that block the immune response. For these 360 RNAi clones, we identified 676 target genes using ”CloneMapper”; http://bioinformatics.lif.univ-mrs.fr/RNAiMap/. To explore the dynamics of gene expression upon infection, we ran RNASeq analyses at 2, 4, 6 and 8 hours post infection and identified the clusters of Di↵erential Expressed Genes (DEG) at di↵erent time point post infection. To identify the potential regulators of these cluster of DEGs, we are analyzing modENCODE chipseq data for 92 TFs, mainly using RSAT tools developed by our collaborator Jacques van Helden and looking for the enrichment of DEGs in potential targets of these TFs. We are validating the targets of di↵erent TFs by using a medium-throughput Fluidigm-based approach. Our final objective is to integrate information from these di↵erent datasets with protein-protein interaction data to build a robust regulatory network that explains the regulation of these defense genes upon infection.

⇤Speaker †Corresponding author: [email protected] ‡Corresponding author: [email protected]

21 P5 – Targeted multicopy transgene integration in C. elegans

1 1 1 1 Iskra Katic ⇤† , Gert-Jan Hendriks , Lan Xu , Helge Grosshans‡

1 Friedrich Miescher Institute for Biomedical Research (FMI) – Basel, Switzerland

The ability to heritably overexpress transgenes is important for analysis of gene function. In C. elegans, however, the existing methods to control copy number and insertion sites of multicopy trans- genes are crude at best. We have shown that DNA repair not based on homologous recombination can be harnessed to insert single-copy transgenes into precise genomic sites. We now extend this method to integration of complex transgenes into the well characterized locus ttTi5605 using the CRISPR/Cas9 system and will present the technique that resulted in successful integrations.

⇤Speaker †Corresponding author: [email protected] ‡Corresponding author: [email protected]

22 P6 – Comparison of ivermectin and moxidectin resistance profiles in the nematode Caenorhabditis elegans

1 1 1 C´ecile Menez ⇤ , Dalia Kansoh , Jean-Fran¸cois Sutra , Anne Lespine

1 ToxAlim (ToxAlim) – Institut national de la recherche agronomique (INRA) : UMR1331 – 180 chemin de Tournefeuille - BP 93173 31 027 Cedex 3, France

The anthelmintic macrocyclic lactones ivermectin (IVM) and moxidectin (MOX) are the most widely administrated drugs to treat nematode infections. Their widespread use has led to the emergence of resistance to these two drugs. Although they have identical modes of action, di↵erences in terms of pharmacokinetics, toxicity and selection for drug resistance have been reported between IVM and MOX. The objective of this study was to investigate and compare di↵erences between IVM and MOX regarding drug selection and development of acquired tolerance against the drug in the model nematode Caenorhabditis elegans. For this purpose, we have evaluated the ability of C. elegans to become tolerant to MOX through stepwise exposure to increasing doses of drug. C. elegans developed resistance to MOX but, after 40 weeks, worms were able to grow only on 5.7 nM of MOX, which was twice lower than the IVM concentration on which IVM-selected worms were able to survive. Then, sensitivity to IVM, MOX and eprinomectin (EPR) of the MOX-selected worms was determined and compared with the wild-type N2 Bristol and an IVM-selected strains with a larval development assay. IVM and MOX displayed the same ecacy in wild-type strain (IC50 of 1.69 0.30 and 1.77 0.25 nM, for IVM ± ± and MOX, respectively). Interestingly, selection with either IVM or MOX lead to targeted resistance against the drug used for the selection associated with cross-resistance to other MLs (with higher eciency of MOX compared to the IVM). Importantly, MOX was more potent in both IVM-selected (12.43 1.65 and 3.06 0.51 nM, for IVM and MOX, respectively) and MOX-selected (12.46 0.96 and ± ± ± 4.24 0.58 nM, for IVM and MOX, respectively) strains, showing that the loss of potency observed ± with IVM after MLs selection has significantly less impact on the potency of MOX. This order of potency was also observed in an LDA with Haemonchus contortus resistant isolate. In addition, there was a significant increase in the transcriptional profiles of a number of ABC transporters and CYP enzymes, while coadministration of verapamil with IVM and MOX potentiated sensitivity to the drug. The results suggest that similar mechanisms are involved in the development of tolerance to MLs after either IVM or MOX selection and that detoxification systems play a partial role in the MLs sensitivity in C. elegans resistant strains. The similarities with parasites are of concern and highlight the use of drug-selected strains of C. elegans, a model organism for research on parasitic nematodes.

⇤Speaker

23 P7 – Characterization of nematode-infecting microsporidia and natural variation in sensitivity of Caenorhabditis nematodes to microsporidia

1 Gaotian Zhang ⇤ , Marie-Anne F´elix†

1 Institut de Biologie de l’Ecole´ Normal Sup´erieure (IBENS) – Ecole Normale Sup´erieure de Paris - ENS Paris – 46 rue d’Ulm 75230 Cedex 05 Paris, France

The microsporidian Nematocida parisii is the first characterized intracellular pathogen of Caenorhab- ditis elegans; and a second Nematocida species, called N. sp. 1, was also reported from an Indian C. briggsae isolate (Troemel et al. 2008). In our lab we further established a collection of wild rhabditid nematodes suspected with microsporidian infection. Here, we characterize molecularly these wild mi- crosporidia and study their specificity of infection. First, the potentially infected rhabditid isolates were characterized using newly designed PCR primers specific for 18S and -tubulin genes of microsporidia. In addition to C. elegans, we found wild C. briggsae as natural host for N. parisii; in addition to C. briggsae, we found C. elegans and C. remanei as natural hosts of N. sp. 1. We further found seven new microsporidian species. Four of them are close to the Nematocida species in microsporidian clade II and preliminarily named N.-like sp. 2 ˜ sp.5. The other three species, only found infecting Oscheius nematode, are very distant, and found in microsporidian clade IV, that includes most human pathogens. They are closest to Orthosomella operophterae (with 18S), and thus preliminarily named Orthosomella-like sp.1 ˜sp.3. Phylogenetic analyses with the 18S and -tubulin genes provide the same relationships of Nematocida spp. and the seven putative new microsporidia species.

Second, specificities of seven nematode-infecting microsporidia (N. parisii, N. sp. 1, N.-like sp. 2 ˜ sp. 3, and Orthosomella-like sp. 1 ˜sp.3.) were tested on four nematode species (C. elegans, C. briggsae, O. tipulae and O. sp. 3 ). N. parisii, N.-like sp. 2 only infect Caenorhabditis.Tothe infection of N. sp. 1, Caenorhabditis are more sensitive than Oscheius. N.-like sp. 3 infects both Caenorhabditis and Oscheius. Orthosomella-like spp. infect Oscheius spp., but not Caenorhabditis. O.-like sp. 2 infects both Oscheius spp., O.-like sp. 1 only infects Oscheius sp. 3, O.-like sp. 3 only infects O. tipulae. Third, two transgenic C. elegans strains ERT54 jyIs8 [C17H1.6p::gfp; myo-2p::mCherry] and ERT72 jyIs15 [F26F2.1p::gfp; myo-2::mCherry], which express a constitutive fluorescent Cherry marker and will induce GFP upon infection with N. parisii (Bakowski et al. 2014), were used in infection tests. Our results show that N. parisii, N. sp. 1, N.-like sp. 2 and N.-like sp. 3 can infect ERT54 and ERT72, forming meronts and spores; N. sp. 1 does not induce the GFP reporter (or only rarely), while the other three induce it consistently, suggesting that C. elegans has a di↵erent transcriptional response to the infection of N. sp. 1 than to other Nematocida spp..

⇤Speaker †Corresponding author: [email protected]

24 P8 – Quantitative Analysis of the Polarization mechanism of a field of Neuronal Precursors in C. elegans

1 1 1 Shilpa Kaur ⇤ , Pierre Lenne , Vincent Bertrand†

1 Institut de biologie du d´eveloppement de Marseille (IBDM) – CNRS : IFR138, Universit´ede la M´editerran´ee- Aix-Marseille II – Campus de Luminy case 907 13288 MARSEILLE CEDEX 09, France

Cell and tissue polarities are essential for the functions of animals and their misregulations are often associated with pathologies. Several studies in animal models have identified molecules involved in tissue polarization and suggest that gradients of extracellular signaling molecules are crucial in this process. However how gradients of extracellular molecules can polarize fields of cells is not understood. One factor that limits our understanding of tissue polarization is the lack of quantitative data on the behavior and interactions between the molecular players in polarization processes occurring in vivo. To better understand the process of tissue polarization we are using the field of neuronal precursors of the C. elegans embryo as a model system. In C. elegans most of the neurons are generated during neurulation by asymmetric divisions oriented along the antero-posterior axis. We have shown that these divisions are regulated by a particular Wnt/beta-catenin pathway and by using gain and loss of function approaches we have identified a role for three Wnt ligands in the polarization of the neuronal precursors before their division. We are currently using quantitative in vivo imaging methods to better understand this polarization process.

⇤Speaker †Corresponding author: [email protected]

25 P9 – Analysis of chromatin factors involved in the initiation and maintenance of neuronal di↵erentiation programs

1 1 1 Guillaume Bordet ⇤† , Carole Couillault , Vincent Bertrand‡ , Lilian Lanteri , Pauline M´el´enec , Amandine Palandri

1 Institut de biologie du d´eveloppement de Marseille (IBDM) – CNRS : IFR138, Inserm : IFR138, Universit´ede la M´editerran´ee- Aix-Marseille II – Campus de Luminy case 907 13288 MARSEILLE CEDEX 09, France

In both vertebrates and invertebrates, postmitotic neurons are often generated by asymmetric divisions of neuronal progenitors such as neural stem cells. We have previously established that in C. elegans the asymmetric divisions of neuronal precursors are regulated by an asymmetric activation of the Wnt pathway. More recently we have identified, during a genetic screen, mutants in the chromatin regulator complex PRC1 that a↵ect the generation of some neurons by asymmetric divisions. They also a↵ect the maintenance of the expression of terminal di↵enrentiation genes important for the identity and functions of those neurons. We are currently investigating how these chromatin factors connect the asymmetric division machinery to terminal di↵erentiation programs and how they strengthen the maintenance of those programs ?

⇤Speaker †Corresponding author: [email protected] ‡Corresponding author: [email protected]

26 P10 – Host pathogen interactions in C. elegans

1 1 1 Jean-Christophe Lone ⇤ , Jonathan Ewbank , Nathalie Pujol†

1 Centre d’Immunologie de Marseille - Luminy (CIML) – Universit´ede la M´editerran´ee- Aix-Marseille II, CNRS : UMR7280, Inserm : U1104 – Parc scientifique et technologique de Luminy - 163, avenue de Luminy - Case 906 - 13288 Marseille cedex 09, France

Infection provokes an immediate defense reaction in the host termed innate immunity. Certain mech- anisms of innate immunity are conserved throughout vertebrates and invertebrates. We are studying the innate immune response of a simple organism C. elegans to infection by a natural fungal pathogen. Through genetic and RNAi screens, we have defined several signaling pathways that lead to the activa- tion of defense genes in the infected tissue. We were able to show that infection provokes the conversion of tyrosine to hydroxyphenyllactic acid (HPLA) and this in turn activates the G-protein coupled re- ceptor DCAR-1 that acts upstream of a PKC-p38 MAPK pathway and the STAT-like transcription factor STA-2. The level of HPLA in the nematode epidermis is also increased upon physical injury or developmental alteration of the cuticle. Thus HPLA appears to be a damage-associated molecular pattern (DAMP), and DCAR-1 to be the first DAMP receptor identified in C. elegans (Pujol et al, CB 2008; Dierking et al., Cell Host & Mic. 2011; Zugasti et al., Nat. Imm 2014). Just how infection leads to an increase in HPLA is, however, unknown. We propose to dissect the mechanism leading to its production by doing a genetic screen in a developmental mutant, with a cuticle defect, wherein a reporter inducible by infection is constitutively turned on, from the early larval stage. To avoid isolating mutants for components downstream of the GPCR, the strain used in the strain will express a constitutively active Galpha protein (GPA-12) in the adult epidermis. Screening for mutants that block reporter gene expression in larvae but not in adults will identify specifically genes acting upstream of GPA-12 and hence potentially reveal the steps leading to the production of HPLA.

⇤Speaker †Corresponding author: [email protected]

27 P11 – Cellular innovations at the origin of pseudogamy in nematodes

1 1 1 Manon Grosmaire ⇤ , Caroline Launay ⇤ , Marie Delattre , Marie-Anne F´elix 2

1 Laboratoire de Biologie Mol´eculaire de la Cellule (LBMC) – CNRS : UMR5239, Universit´eClaude Bernard - Lyon I (UCBL), Ecole´ Normale Sup´erieure (ENS) - Lyon – ENS de Lyon 46 all´eed’Italie 69364 LYON Cedex 07, France 2 Institut de Biologie de l’Ecole´ Normale Sup´erieure (IBENS) – Ecole Normale Sup´erieure de Paris - ENS Paris – 46 rue d’Ulm 75230 Cedex 05 Paris, France

Pseudogamy is a mode of reproduction in which the fertilization of an oocyte by a sperm cell is necessary even tough the male DNA does not contribute to the zygote genome in most embryos. Em- bryos in which the sperm DNA does not decondense give rise to 100% females, while the contribution of sperm DNA allow the production of rare males in the population (Nigon, 1942). Pseudogamy has been described in several species of nematodes. It has been proposed that oocytes with incomplete meiosis will not utilize the male DNA, while oocytes undergoing the regular two steps of meiosis allow the decondensation of the male DNA. These observations suggest that pseudogamy is the consequence of a stochasticity in the progression through meiosis, accompanied by a control of the paternal DNA. We have recently identified several pseudogamous species within the Mesorhabditis genus. In order to study the molecular and cellular innovations that have allowed the emergence of such paradoxical reproductive strategy, we are establishing tools to develop a genetic approach in one of this strain. We will present our di↵erent strategies. Among the 20 new strains of the Mesorhabditis genus that have been collected, 6 have a classic male/female mode of reproduction and 14 are pseudogamous. Sequencing of ITS, 18S and 28S al- lowed us to obtain a first phylogeny, indicating that pseudogamous species constitute a monophyletic group. Combined with genetic crosses and morphological description, we have so far identified at least 8 independent pseudogamous species, and several strains per species.

We selected one pseudogamous strain isolated in Orsay, JU2817, as our reference strain. Two other strains (isolated in France or UK) belong to the same species and will serve as polymorphic strains for further genetic studies. In JU2817, 80% of oocyte display an incomplete meiosis and therefore only 10% of males are present in the population at 20 C. The strain has been inbred for 10 generations and the DNA and RNA are currently being prepared for genome and transcriptome sequencing. We are also trying to establish the CRISPR/Cas9 technique in this strain. Evidences that environmental conditions can influence the sex ratio in pseudogamous species brought us to further investigate the e↵ect of temperature on the sex ratio of JU2817. Our preliminary results suggest that the sex ratio and the fertilization ecacy are both influenced by the size of the population, but not by the temperature.

⇤Speaker

28 P12 – How cellular plasticity promoted and controlled an organism?

1 1 1 Thomas Le Gal ⇤ , Arnaud Ahier , Sophie Jarriault

1 IGBMC – CNRS UMR 7104, Inserm U 964, UdS – 1 rue Laurent Fries / BP 10142 / 67404 Illkirch CEDEX, France

We are interested in the mechanisms allowing a cell to change its identity. For this, we use a natural transdi↵erentiation event where a rectal cell converts into a moto-neuron, in C. elegans. Work in the lab has shown that this cell type conversion involves first the erasure of the rectal identity, before re-di↵erentiation into a moto-neuron. However this transient de-di↵erentiation is not coupled with a reversal to a multi- or pluri-potent state. Further work has shown that a nuclear complex is necessary for the de-di↵erentiation step, and that its members are conserved pluripotency factors. Pluripotency is one important cellular property of early embryonic cells in mammals that allows these cells to give rise to a variety of di↵erentiated cells types, and ultimately to a functional organism. How is pluripotency established and maintained has been the subject of intensive work in the last decades, but is still not fully understood. Landmark experiments by Yamanaka show that 4 transcription factors, oct3/4, sox-2, c-myc and klf4, are sucient to turn specialised cells into pluripotent cells, called iPS cells. In addition, sox2 and oct4 are at the center of the so-called pluripotency network, including sall4 or mta1, which is necessary to maintain pluripotency. We have found that these same 4 factors are necessary to promote de-di↵erentiation in vivo, while not establishing pluripotency. We now are closely investigating how these factors function during the initial phases of transdi↵erentiation. Indeed Arnaud Ahier has shown that ceh-6 /oct4 and sox-2 can be required at successive steps of transdi↵erentiation, prior to the initiation. To understand whether and what intrinsic properties of CEH-6/OCT4 and SOX-2 could underlie their ability to promote de-di↵erentiation but not pluripotency in the worm, as opposed to their mammalian counterparts, Arnaud has examined CEH-6 and SOX-2 interaction surfaces in C. elegans. We are further trying to understand which domains of CEH-6/OCT4 and SOX-2 are important for the transdi↵erentiation process as well as mapping the interaction pattern of ceh-6 and sox-2 with respect to their transcriptional activity, and will report on our latest findings at the meeting.

⇤Speaker

29 P13 – The SET-2/SET1 histone H3K4 methyltransferase maintains genome stability in the Caenorhabditis elegans germline

1 2 1 1 Marion Herbette ⇤ , Marine Mercier , Steve Garvis , Matthieu Caron , 1 1 Francesca Palladino† , Val´erie Robert‡

1 Laboratory of Molecular and Cellular Biology – Ecole´ Normale Sup´erieure - Lyon – 46 all´ee d’italie 69007 Lyon, France 2 Centre de g´en´etique et de physiologie mol´eculaire et cellulaire (CGphiMC) – CNRS : UMR5534, Universit´e Claude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Bˆatiment Gregor Mendel 16 rue Rapha¨elDubois 69622 VILLEURBANNE CEDEX, France

Histone H3 Lysine 4 methylation (H3K4me) is deposited by the conserved SET1/MLL family methyltransferases. SET-2, one of the two SET1/MLL family members encoded by the C. elegans genome, is required to catalyze both germline H3K4me2 and H3K4me3. In germlines missing SET-2, misexpression of germline and somatic genes is observed that correlates with loss of germline pluripo- tency and transdi↵erentiation of germ cells into somatic cell types (Robert, Mercier et al, 2014). We will present recent data showing that in addition to preserving germline identity, SET-2 and H3K4me are also required for genome stability in the C. elegans germline. We demonstrated that the absence of SET-2 results in (i) a mutator phenotype, (ii) increased sensitivity to DNA damage inducing agents and (iii) an accumulation of DNA double strand breaks (DSBs) and fragmented chromosomes following exposure to ionizing radiation (IR). However, the DNA damage response pathway that coordinates cell cycle arrest, DNA damage repair and apoptosis is still functional in the absence of SET-2. Based on these observations, we hypothesize that the absence of H3K4 methylation in the germline might a↵ect the respective use of conservative homologous recombination and error-prone end-joining pathways to repair DNA DSBs in the C. elegans germline. We will present genome-wide sequencing and genetic approaches that we are now using to test this hypothesis.

⇤Speaker †Corresponding author: [email protected] ‡Corresponding author: [email protected]

30 P14 – Mechanosensing in C. elegans embryogenesis: Hunting for a putative mechanosensor

1 1 Shashi Kumar Suman ⇤ , Michel Labouesse†

1 Institut de Biologie Paris-Seine – Universit´ePierre et Marie Curie [UPMC] - Paris VI – Biologie du D´eveloppement, UMR7622, Institut de Biologie Paris-Seine, UPMC, 9 quai Saint Bernard, 75252 Paris, France

Mechanosensing refers to a process whereby mechanical inputs are sensed and transduced as chemi- cal or electrical signal to initiate or accelerate a downstream pathway. Many important biological events are mediated by this process including tissue di↵erentiation, morphogenesis and also in pathophysio- logical conditions such as tumor progression, but their mechanisms at a molecular level remain poorly understood. Mechanotransduction signaling in vivo can be triggered by body-wall muscle contractions (elongating C. elegans embryos), cell shape changes (Drosophila embryos), hydrodynamic forces (ven- tricle of mouse brain), or blood flow (heart development in zebrafish). During C. elegans development, embryos elongate 4-fold without additional cell division or migration. This process is highly robust and invariable. Previous studies demonstrated that hemidesmosomes (cell attachments to the extracellular matrix) play a critical role in mechanosensing by stabilizing the sca↵olding protein GIT-1 in response to muscle input, but little is known about how it works at the molecular level (Zhang et al., 2011). Therefore we aimed to characterize a putative binding partner of the earliest known e↵ector (GIT-1) of mechanosensing. For this, we used both in vitro and in vivo (CRISPR-CAS9 ) tools to identify its binding partners (if any). Interestingly, we found that a core component of the hemidesmosome i.e., VAB-10 strongly interacts with GIT-1 molecularly and genetically. Far-Western blotting suggests that purified VAB-10 and GIT-1 interact molecularly in vitro. Genetic interaction studies revealed that a mutation a↵ecting the SH3 domain present within a spectrin repeat of VAB-10 strongly in- teracts with mutations in git-1 and also with pak-1 (a player of mechanotransduction pathway). In double mutants background, embryos arrested prior to the two-fold stage, a phenotype also noticed in hemidesmosome-deficient embryos. This result suggests that the SH3 domain of VAB-10 provides an interaction platform for diverse players in response to physical cues in mechanosensing pathway. We would also like to extend our studies in the context of characterizing mechanosensing properties using a combination of genetic tools (transgenic line) in vivo, and biophysical tools (AFM) in vitro. Thus, understanding how mechanosensors and their signaling cascades operate should elucidate a cellular phenomenon in a better way.

⇤Speaker †Corresponding author: [email protected]

31 P15 – Identification of novel regulators of GABAergic synaptogenesis in the nematode Caenorhabditis elegans.

1 1 1 Marine Gueydan ⇤ , B´erang`ere Pinan-Lucarre , Aurore Valfort-C´ecile , 1 Jean-Louis Bessereau†

1 Centre de g´en´etique et de physiologie mol´eculaire et cellulaire (CGphiMC) – CNRS : UMR5534, Universit´e Claude Bernard - Lyon I – UNIVERSITE CLAUDE BERNARD LYON 1 Bˆatiment Gregor Mendel 16 rue Rapha¨elDubois 69622 VILLEURBANNE CEDEX, France

In the central nervous system, the inhibitory system plays a key role in neuronal network excitabil- ity and defects in the excitatory vs inhibitory balance could lead to neuropathies. To identify novel genes and mechanisms involved in the formation and the regulation of inhibitory synapses, we use the inhibitory GABAergic neuromuscular junction (NMJ) of the nematode Caenorhab- ditis elegans as a genetically tractable model. At these synapses, fast neurotransmission is ensured by type A ionotropic GABA receptors (GABAR), which form post-synaptic clusters in front of GABA release sites. Specifically, we performed an EMS genetic screen based on the direct visualization of fluorescently tagged GABAR in vivo in a knock-in strain. We identified 35 mutants with abnormal GABAR local- ization among the 1728 mutagenized haploid genomes isolated. We characterized and categorized a first set of 13 mutants that displayed strong GABAR mislocalization. We used a novel whole genome sequencing strategy to simultaneously map and identify mutations responsible for the GABAR local- ization defect without any prior time-consuming genetic mapping. We are currently validating some of the potential mutations and reproducing the procedure for a second set of mutants to enlarge our candidate genes list.

⇤Speaker †Corresponding author: [email protected]

32 P16 – Micro-movements of the mitotic spindle poles reveal cell division mechanics.

1 1 1 1 Benjamin Mercat , Xavier Pinson ⇤ , H´el`ene Bouvrais , Jacques P´ecr´eaux

1 Institute of Genetics and Developmental biology of Rennes (IGDR) – CNRS, Universite de Rennes 1 – CNRS UMR 6290 - Facult´ede M´edecine (Univ. Rennes 1) 2 avenue du Prof. L. Bernard, CS 34317, 35043 Rennes cedex, France, France

Mitosis and the correct segregation of genetic material lie at the heart of development and survival of all living organisms. The mitotic spindle, indispensable to these processes, is a structure comprising dynamical microtubules as well as a variety of molecular motors and their regulators. Although the spindle has been extensively studied biochemically, its dynamics and that of its various components remain elusive. To study the dynamics of the mitotic spindle, we developed an image processing base, non-invasive method combined to a heuristic model to accurately measure mechanical parameters along time. We used this to address how forces (cortex-, kinetochore- and spindle midzone-generated) are regulated within the mitotic spindle of the C. elegans one-cell embryo. Indeed, forces have been proposed to be essential for the detection and correction of merotelic chromosome attachments that escape the control of the metaphase/anaphase checkpoint and can give rise to aneuploidy.

To this end, we tracked fluorescently labeled spindle pole at high temporal and spatial resolution and analysed micro-fluctuations of spindle length in vivo, to obtain a blueprint of the mechanical behavior of the spindle and its evolution over time. In control embryos, metaphase appeared dominated by damping, consistent with the slow spindle elongation observed. At anaphase onset, mechanical ”rigid- ity” collapsed, before slowly increasing about 50s later to reach a regime where damping and inertia dominated, suggesting a dramatic re-arrangement of the spindle. Our investigations of the micro-movements enabled us to probe the mitosis mechanics close to the physiological conditions with a minimally perturbative approach. This is being applied to characterize the roles of forces in the post-anaphase correction mechanism of merotelic attachments and paves the way to understanding yet elusive and poorly studied properties of the mitotic spindle.

⇤Speaker

33 P17 – The C. elegans K cell as a new model to study cellular potential, asymmetric cell division and cell type conversion

1 1 Christelle Gally ⇤ , Martina Hajduskova , Sophie Jarriault†

1 IGBMC – CNRS UMR 7104, Inserm U 964, UdS – 1 rue Laurent Fries / BP 10142 / 67404 Illkirch CEDEX, France

Asymmetric cell division (ACD) ensures the balance between cell proliferation and di↵erentiation. Stem cells undergo ACD to self-renew while giving rise to a daughter cell that enters the di↵erentiation path. To date diverse mechanisms of ACD have been described in di↵erent experimental models. However, the complex regulation network of ACD and its impact on stem cell potential is still not fully understood. The studies of stem cells ACD in vitro have several limitations, such as absence of the natural cellular environment which may impact on self-renewal abilities, the symmetry of the division or the restriction of cellular potential. Here, we introduce a new cellular in vivo model to study ACD impact on cellular potential within a complex tissue context, namely the rectal epithelial tissue, yet at a single-cell resolution. In C. elegans, an epithelial cell named ”K” is a part of the larval rectal tube. Interestingly, during development the K cell, which has all features of a fully di↵erentiated epithelial cell, divides in a stem cell-like manner to produce the rectal epithelial cell K.a and another daughter cell (K.p) that then becomes the DVB neuron. In order to understand the mechanism(s) controlling the K-to-DVB formation, we have performed an RNAi screen and tested several genes known to be important in ACD. Furthermore, we have identified K, K.a and K.p-specific markers and investigated their temporal activity. Owing to these markers, we have been able to characterize how the K cell division is a↵ected in mutants that lack the DVB neuron. We have started to elucidate the relationships between key genetic players of the K cell division. Currently, we are testing how the orientation of the K cell division impacts on K.p cell fate and what mechanisms might be at play after ACD to convert the K.p daughter into a DVB neuron. Our powerful cellular in vivo model allows dissecting the molecular circuitry governing the decision between self-renewal and commitment to di↵erentiation.

⇤Speaker †Corresponding author: [email protected]

34 P18 – DRP-1, AIF and mTOR : a link between mitochondria morphology and muscle degeneration in C. elegans ?

1 1 1 Charlotte Scholtes ⇤ , St´ephanie Bellemin , Edwige Martin , Ma¨ıt´e Carre-Pierrat 2, Marie-Christine Mariol 1, Kathrin Gieseler 1, Ludivine Walter 1

1 Centre de g´en´etique et de physiologie mol´eculaire et cellulaire (CGphiMC) – CNRS : UMR5534, Universit´e Claude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Bˆatiment Gregor Mendel 16 rue Rapha¨elDubois 69622 VILLEURBANNE CEDEX, France 2 Plateforme ”Biologie de Caenorhabditis elegans” – CNRS : UMS3421 – Universit´eClaude Bernard - Lyon I bˆatiment G. Mendel 16, rue Rapha¨elDubois 69622 Villeurbanne Cedex, France

Muscle degeneration is a common feature of muscle aging and muscular dystrophies such as Duchenne Muscular Dystrophy (DMD). Our lab has established a Caenorhabditis elegans mutant with progressive dystrophin-dependent muscle degeneration: the dys-1(cx18);hlh-1(cc561) double mutant worm called the C. elegans DMD model. This model exhibits dramatic changes in mitochondrial morphology com- pared to wild-type worms suggesting a deregulation in the fusion/fission mitochondrial balance. My goal is to shed light on the role of mitochondria dynamics in the molecular mechanisms leading to muscle degeneration. To start, we first focused on DRP-1, a protein required for mitochondrial fission. We introduced in the C. elegans DMD model a null mutation drp-1(tm1108).TheDMD;drp-1(tm1108) mutants presented reduced mitochondrial fragmentation compared to DMD mutants. Furthermore, DMD;drp-1(tm1108) mutants exhibited reduced muscle degeneration and increased mobility. DRP-1 is well known to be im- plicated in cell death processes. In C. elegans, the pro-apoptotic function of DRP-1 is dependent on its cleavage by the CED-3 caspase. We generated DMD;drp-1(tm1108) transgenic lines expressing DRP-1 with mutated CED-3 cleavage site. Interestingly, our data suggest that DRP-1 cleavage by CED-3 is required for DRP-1 to decrease muscle degeneration. Altogether, the pro-fission and pro-apoptotic protein DRP-1 seems to be implicated in pathological muscle degeneration.

After these first observations, we aimed at identifying other genetic suppressors of dystrophin de- pendent muscle degeneration playing a role in mitochondria dynamics. Large screen on the C. elegans DMD model allowed for the identification of 60 genes, which decrease muscle degeneration after RNAi knock-down. Among them, we identified 28 candidate genes that participate in mitochondria biology. We tested the 28 RNAi candidates for an e↵ect on mitochondria morphology of DMD worms. We found that knock-down by RNAi of wah-1 (AIF homolog) and let-363 (mTOR homolog) can reduce mitochondrial fragmentation of DMD mutants. Our findings provide the first evidence that WAH-1 a↵ects mitochondria morphology in muscle cells. Moreover, reducing WAH-1 or LET-363 levels in absence of DRP-1 can further decrease muscle degen- eration of the C. elegans DMD model than wah-1 RNAi or let-363 RNAi or drp-1(tm1108) mutation alone suggesting at least in part distinct molecular pathways.

⇤Speaker

35 P19 – Is unc-70 /-spectrin a functional regulator of the neuronal potassium channel unc-58 ?

1 1 1 Philippe Tardy ⇤ , Melissa Zouak , Thomas Boulin†

1 Institut NeuroMyoG`ene (INMG) – Universit´eClaude Bernard-Lyon I - UCBL (FRANCE) – 8 RUE RAPHAEL DUBOIS, 69100 VILLEURBANNE, France

Two-pore domain potassium channels (K2P) compose a family of highly conserved potassium- selective ion channels responsible for the establishment and maintenance of the electrical membrane potential of metazoan cells. Despite their fundamental role, little is known about the cellular processes that control K2P channel function in vivo. In particular, we know only few factors that directly control the number, the activity and the localization of K2Ps at the cell surface. Thus, we have performed a large-scale genetic screen targeting the neuronal UNC-58 channel in order to identify new specific regulators of neuronal K2P channels in C. elegans. Gain-of-functions mutants of unc-58 display a strong paralysis phenotype (e665, Brenner, 1974). Using Mos1 and EMS mutagenesis, we have isolated 97 intragenic and 36 extragenic suppressor mutants. We have found that complete loss of UNC-58 function is associated with a significant decrease in thrashing frequency, comparable to the loss of the main cholinergic receptor at neuromuscular junctions. This suggests an important role for UNC-58 in the neuromuscular system.

Among our extragenic suppressors, we have found three alleles of unc-70 /-spectrin and three alleles of unc-44 /ankyrin. These cytoskeletal proteins interact with each other to form a membrane endoskeleton ensuring elasticity of neuronal and erythrocyte plasma membranes. In C. elegans, mutants of unc-70 possess a striking phenotype in which the axons of GABAergic motoneurons are very fragile and break during post-embryonic development due to mechanical stress (Hammarlund, 2007). Our three mutants are likely hypomorphic alleles, since they are much healthier than unc-70 null mutants. They still display axon breakage defects, albeit at a lower penetrance than null mutants. Moreover, the pene- trance for axon breakage is variable between each of the three alleles, even if they equally suppress unc-58(e665). Surprisingly, while axon breakage is reported to occur in GABAergic and cholinergic neurons alike, a large number of unidentified motoneurons expressing UNC-58 show no axon breakage defects in our unc-70 mutants. Our results suggest that these new alleles may allow us to genetically dissociate -spectrin role between maintenance of axonal integrity and regulation of UNC-58 function. We can formulate two main hypotheses concerning the suppression of unc-58(e665) by the loss of unc-70. (1) The channel could be regulated by a direct interaction with the spectrin network. Such in- teraction has already been reported in mammalian cardiomyocyte for the TREK-1 K2P channel (Hund, 2014), although the nature of this interaction has not been yet elucidated. We are currently generating knockin strains for UNC-58 to visualize channel expression and localization in vivo. Alternatively, (2) loss of -spectrin could indirectly suppress unc-58(e665) behavior by disrupting the neuronal network. We have begun observing the architecture of di↵erent neuron classes to address this hypothesis.

⇤Speaker †Corresponding author: [email protected]

36 P20 – The role of sel-10 in transdi↵erentiation

1 2 1 C´ecile Delance ⇤† , Steven Zuryn , Sophie Jarriault

1 Labo Jarriault – IGBMC – 1, rue Laurent Fries, France 2 labo Zuryn – Queensland Brain Institute The University of Queensland Brisbane, 4072 Queensland, Australia

Transdi↵erentiation (TD) is a process during which one di↵erentiated cell changes its identity and become another specialized cell type. In our laboratory, we study a well-characterized single cell transdi↵erentiation event which occurs naturally in the rectum of the worm. One of the 6 rectal cells, named Y, transdi↵erentiates into the PDA motor neuron (Y-to-PDA). This mechanism begins in Y at the L1 larval stage and is completed at the L3 larval stage. In this poster, I present our study on sel-10 which is an ubiquitin ligase E3 involved in Y-to-PDA transdi↵erentiation. We found that sel-10 is genetically interacting with an histone demethylase (JMJD-3.1) which also have a positive role during TD. One model is that SEL-10 ubiquitinates a substrate which acts as a probable repressor of Y-to-PDA TD, triggering its degradation by the proteasome. To test this hypothesis, we are examining which SCF complex is involved in Y transdi↵erentiation. In addition, we have set up di↵erent strategies, using genetics and RNAi screening approaches, to identify SEL-10 substrate(s). We will thus report on our progresses at the meeting.

⇤Speaker †Corresponding author: [email protected]

37 P21 – Cryptic evolution behind a conserved asymmetric embryonic division in nematodes

1 2 Marie Delattre ⇤ , Aurore-C´ecile Valfort , Caroline Launay , Marie S´emon

1 Laboratoire de Biologie Mol´eculaire de la Cellule (LBMC) – CNRS : UMR5239, Universit´eClaude Bernard - Lyon I, Ecole´ Normale Sup´erieure (ENS) - Lyon – ENS de Lyon 46 all´eed’Italie 69364 LYON Cedex 07, France 2 Laboratoire de biologie mol´eculaire de la cellule (LBMC) – UMR5239, Ecole Normale Sup´erieure de Lyon, Universit´eClaude Bernard Lyon, Hospices Civils de Lyon – Laboratoire de Biologie Mol´eculaire de la Cellule UMR5239 CNRS/ENS Lyon/UCBL/HCL Ecole normale sup´erieure de Lyon 46, all´eed’Italie 69364 Lyon cedex 07, France

Very little attention has been given to the pattern of variations for cellular traits across evolution. This contrasts with numerous studies on the evolutionary dynamics of molecules, genomes and devel- opmental processes. Because evolutionary changes ultimately arise from changes at the cellular level, the evolutionary dynamics of cellular processes remains to be explored. We are studying the evolution of the mitotic spindle, by using nematode embryos as a cellular model. Mitotic spindle dynamics has been extensively studied the one-cell embryo of C. elegans. As the spindle elongates during anaphase, it becomes asymmetrically positioned, giving rise to two daughter cells of unequal size and fate. We quantified spindle movements in ˜40 di↵erent species of nematodes for which the first embryonic division is also asymmetric. We discovered that this conserved output phenotype is achieved by a very di↵erent combination of spindle movements between species. This demonstrates that cryptic changes in the mechanical forces and/or material properties of the spindle have occurred across nematode evolution. We have analysed the pattern of variation with the explicit aim of i) uncovering the directionality of changes across the phylogeny and ii) uncovering the conserved properties of the mitotic spindle.

⇤Speaker

38 List of participants

[email protected] :: Abou-Ghali Majdouline • [email protected] :: Aguilaniu Hugo • [email protected] :: Al Rawi Sara • [email protected] :: Alkan Cigdem • [email protected] :: Andrini Olga • [email protected] :: Baritaud Mathieu • [email protected] :: Becker Sarah • [email protected] :: Bedet C´ecile • [email protected] :: Bellemin St´ephanie • [email protected] :: Belougne J´erˆome • [email protected] :: Bertrand Vincent • [email protected] :: Bessereau Jean-Louis • [email protected] :: Bordet Guillaume • [email protected] :: Boulin Thomas • [email protected] :: Boyer H´el`ene • [email protected] :: Bulle Maxime • [email protected] :: Caillard C´eline • [email protected] :: Caron Matthieu • [email protected] :: Carre-Pierrat Ma¨ıt´e • [email protected] :: Dalessandro Manuela • [email protected] :: Delance C´ecile • [email protected] :: Deuve Jane • [email protected] :: El Mouridi Sonia • [email protected] :: Ewbank Jonathan • [email protected] :: F´elix Marie-Anne •

39 [email protected] :: Fischer Nadine • fl[email protected] :: Flore Beurton • [email protected] :: Gally Christelle • [email protected] :: Garvis Steven • [email protected] :: Gendrel Marie • [email protected] :: Gieseler Kathrin • [email protected] :: Gomes Jos´e-Eduardo • [email protected] :: Granger Laure • [email protected] :: Grosmaire Manon • [email protected] :: Grover Manish • [email protected] :: Guet David • [email protected] :: Gueydan Marine • [email protected] :: He Le • [email protected] :: Herbette Marion • ho↵[email protected] :: Ho↵ Sarah • [email protected] :: Joly Nicolas • [email protected] :: Jospin Maelle • [email protected] :: Katic Iskra • [email protected] :: Kaur Shilpa • [email protected] :: Lain´eViviane • [email protected] :: Lardennois Alicia • [email protected] :: Launay Caroline • [email protected] :: Laurencon Anne • [email protected] :: Le Gal Thomas • [email protected] :: Lee Song Hua • [email protected] :: Lee Song Hua • [email protected] :: Lone Jean-Christophe • [email protected] :: Luccardini Camilla • [email protected] :: Mangold S´everine • [email protected] :: Mariol Marie-Christine • [email protected] :: Martin Edwige • [email protected] :: Martino Lisa •

40 [email protected] :: Menez C´ecile • [email protected] :: Mercier Marine • [email protected] :: Mergoud Dit Lamarche Adeline • [email protected] :: Merlet Jorge • [email protected] :: Michaux Gr´egoire • [email protected] :: Moal St´ephane • [email protected] :: Molin Laurent • [email protected] :: Mounier Nicole • [email protected] :: Mounier Nicole • [email protected] :: Nahaboo Wallis • [email protected] :: Neri Christian • [email protected] :: Palladino Francesca • [email protected] :: Perrois Charl`ene • [email protected] :: Pinan-Lucarre Berangere • [email protected] :: Pinson Xavier • [email protected] :: Pintard Lionel • [email protected] :: Plastino Julie • [email protected] :: Pujol Nathalie • [email protected] :: Richaud Aur´elien • [email protected] :: Richaudeau B´en´edicte • [email protected] :: Robert Val´erie • [email protected] :: Romatif Oceane • [email protected] :: Scholtes Charlotte • fl[email protected] :: Solari Florence • [email protected] :: Suman Shashi Kumar • ta↵[email protected] :: Ta↵oni Clara • [email protected] :: Tak Saurabh • [email protected] :: Tardy Philippe • [email protected] :: Thakur Nishant • [email protected] :: Touba Ilhem • [email protected] :: Valfort Aurore-C´ecile • [email protected] :: Vuong Thanh •

41 [email protected] :: Walter Ludivine • [email protected] :: Walter Ludivine • [email protected] :: Weinreb Alexis • [email protected] :: Zhang Gaotian •

42 Author Index

Kansoh, Dalia, 23 AHIER, Arnaud, 29 Katic, Iskra, 22 Al Rawi, Sara, 16 Kaur, Shilpa, 25 Atlas, Emily, 5 Barbry, Pascal, 10 LABOUESSE, Michel, 31 BARITAUD, Mathieu, 13 Labouesse, Michel, 12 Bedet, C´ecile, 9 Lanteri, Lilian, 26 BELLEMIN, St´ephanie, 35 Launay, Caroline, 28, 38 BELOUGNE, J´erˆome,19 Le Gal, Thomas, 29 Bertrand, Vincent, 25, 26 Lebrigand, Kevin, 10 BESNARD, Fabrice, 14 Lecroisey, Claire, 7 Bessereau, Jean-Louis, 32 Lee, Song Hua, 18 bessereau, Jean-Louis, 6 Lenne, Pierre, 25 Beurton, Flore, 9 Lespine, Anne, 23 Boned, Annie, 18, 21 Lone, Jean-Christophe, 27 Bordet, Guillaume, 26 M´el´enec, Pauline, 26 Boulin, Thomas, 7, 36 Marguet, Didier, 11 Bouvrais, H´el`ene, 33 MARIOL, Marie-Christine, 13, 35 BULLE, Maxime, 21 Marsac, Roxane, 20 Caillard, C´eline, 19 MARTIN, Edwige, 13, 35 Caron, Matthieu, 9, 30 martino, lisa, 15 Carre-Pierrat, Ma¨ıt´e,35 Menez, C´ecile, 23 Couillault, Carole, 26 Mercat, Benjamin, 33 MERCIER, Marine, 30 Daignan-Fornier, Bertrand, 20 Mergoud dit Lamarche, adeline, 6 DELANCE, C´ecile, 37 Merlet, Jorge, 16 Delattre, Marie, 28, 38 Molin, Laurent, 6 Deuve, Jane, 16 el mouridi, sonia, 7 Omi, Shizue, 18, 21 Ewbank, Jonathan, 10, 11, 18, 21, 27 P´ecr´eaux, Jacques, 33 F´elix, Marie-Anne, 24, 28 Palandri, Amandine, 26 FELIX, Marie-Anne, 14 Palladino, Francesca, 9, 30 Perrois, Charl`ene, 16 Gally, Christelle, 34 Pinan-Lucarre, B´erang`ere, 32 Galy, Vincent, 16 Pinson, Xavier, 33 Garvis, Steve, 30 Pintard, Lionel, 15 Gendrel, Marie, 5 Pujol, Nathalie, 10, 11, 18, 21, 27 GIESELER, Kathrin, 13, 35 Gieseler, Kathrin, 6 Robert, Val´erie, 30 Gomes, Jos´e-Eduardo, 20 Grosmaire, Manon, 28 S´emon, Marie, 38 Grosshans, Helge, 22 Saint-Marc, Christelle, 20 Gueydan, Marine, 32 SCHOLTES, Charlotte, 35 Solari, Florence, 6 Hajduskova, Martina, 34 HE, LE, 10 Hendriks, Gert-Jan, 22 43 Herbette, Marion, 30 Hobert, Oliver, 5 Jarriault, Sophie, 29, 34, 37 SUMAN, Shashi Kumar, 31 Sutra, Jean-Fran¸cois, 23

Ta↵oni, Clara, 11 Tardy, Philippe, 7, 36 Thakur, Nishant, 21

Valfort, Aurore-C´ecile, 38 Valfort-C´ecile, Aurore, 32 Vuong-Brender, Thanh, 12

WALTER, Ludivine, 35

Xu, Lan, 22

ZHANG, Gaotian, 24 Zouak, Melissa, 7, 36 Zuryn, Steven, 37

44