KEYNOTE SESSIONS Conserved programs for producing and maintaining high quality oocytes Steven DeLuca, Ethan Greenblat, Matthew Sieber, Liang-Yu Pang, Megha Ghildiyal and Allan Spradling Department of Embryology, Howard Hughes Medical Institute, Carnegie Institution for Science, Baltimore, MD USA 21204. Our laboratory has studied multiple mechanisms used during oocyte development that are significantly conserved between Drosophila and mice. Among these are mechanisms controlling the formation and function of germ cell chromatin. By introducing reporter genes at more than 100 sites throughout the genome, and by carrying out ChiP analyses on FACS-isolated germ cells we have investigated how the functional and modification states of chromatin facilitate Drosophila female germ cell development. Eggless-dependent formation of H3K9me3-enriched heterochromatin occurs prior to the onset of meiosis and may repress non-homologous recombination. E(z)-dependent modification of Polycomb target gene loci blocks the ectopic activation of male-specific germline genes, while CBP-dependent H3 acetylation is essential for nurse cell function. We have also characterized how oocytes store lipids following an ecdysone pulse at stage10, and transition to a quiescent state following down-regulation of InR/Akt signaling. Disassembly of mitochondrial respiratory complexes mediated by Gsk3 stimulates gluconeogenesis and glycogen accumulation, followed by metabolic quiescence. Using ribosome profiling we have characterized the residual translational program of quiescent, mature eggs that maintains egg quality while they are stored in the ovary. Over an approximately two-week lifespan at 25 oC, oocytes modulate the translation of mRNAs that are largely associated with large RNP complexes. Several abundant proteins, including E3 ubiquitin ligases and chaperones, function to maintain oocyte viability during this period. Eggs with suboptimal nutrients, incomplete mitochondrial shutdown, or with reduced proteostasis capacity do not immediately become inviable, but produce defective embryos at an elevated frequency. Our studies emphasize the critical importance during oogenesis of the multiple sophisticated mechanisms that generate and maintain oocyte quality. Evolutionary conservation and divergence in function of a homologous neuron underlying a complex behavior David Stern Janelia Research Campus The neural basis for behavioral evolution is poorly understood. Functional comparisons of homologous neurons can reveal neural differences underlying novel behavior patterns, but homologous neurons cannot be identified and manipulated in most taxa. Here, we take a new strategy to this problem by introducing genetic reagents from Drosophila melanogaster into other Drosophila species, which allowed us to compare the anatomy, physiology, and function of homologous song neurons between species that exhibit both conserved and derived song types. We found that a descending neuron with conserved electrophysiological properties is required for different song types in D. melanogaster and D. yakuba, although these songs are produced in similar behavioral contexts. Thus, this neuron has retained a functional role in producing a courtship song in a specific context, but functionally diverged in the song type it produces. This experimental approach can be generalized to other neurons and therefore provides an experimental framework for studying how the nervous system has evolved to generate behavioral diversity. On growth and form in petals Vivian Irish Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520 Petals are an excellent system for studying plant organogenesis; they have a simple structure with relatively few cell types. Over the years, my group has focused on various aspects of petal development, from characterizing homeotic genes required for petal identity, to dissecting gene regulatory networks necessary for petal initiation, growth and differentiation. More recently, we have focused on cell type differentiation, with a particular emphasis on understanding the mechanisms involved in shaping conical petal epidermal cells. PLATFORM SESSIONS NRPM, novel signaling regulators at the plasma membrane Xueyi Xue and Juan Dong Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ 08854 Plants are rooted in the soil, but generally well adapted to a wide range of environmental conditions. The plasma membrane integrates the cell with its extracellular environment. Behand the remarkable ability of plants to cope with external stresses and still strive, sophisticated and efficient mechanisms to establish and maintain plasma membrane homeostasis is involved. However, how sophisticated and dynamic signaling across the plasma membrane is achieved by a dedicated balance between positive and negative regulations remains a major challenge in understanding plant signal transduction. Here, we will discuss a newly identified signaling regulator at the plasma membrane, NRPMs (Novel Regulator at the Plasma Membrane). We characterize their loss- of-function mutant phenotype and their subcellular localization and functional inter-dependence with the receptor-like kinases. The NRPMs represent a new class of regulators at the plasma membrane in plants. Rapid phenotyping of the developing mouse nervous system by single-cell mass cytometry. Eli Zunder Department of Biomedical Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, VA 22908 Mass cytometry is a flow cytometry variant that uses isotopically pure rare earth metals conjugated to antibodies or other affinity reagents, permitting measurement of over 40 markers simultaneously at the single cell level. This approach has proven highly successful in the study of immune cell types, but has not yet been used to examine cells of the nervous system, perhaps because neural tissue is challenging to dissociate into a single-cell suspension. In this presentation, we describe single-cell dissociation of microdissected neural tissues, and the development of neuronal and glial-specific antibody panels that pave the way for developing a proteomic cell atlas of the developing nervous system. The neural mass cytometry platform described here can be readily applied by other research groups to perform high-throughput neural phenotyping. Macrophages directly alter fibroblast activity during epimorphic tissue regeneration and fibrotic healing Jennifer Simkin University of Kentucky, USA Injury culminates in tissue regeneration for some tetrapods and fibrotic healing for others, and there is mounting evidence that an initial immune response is essential for both processes. Macrophages, key orchestrators of the immune response, are necessary for proper tissue regeneration across epimorphic regeneration models including mammals. Macrophages are also known to promote fibrotic healing in models of wound repair thus prompting the following question: how do macrophages direct tissue regeneration in one context and fibrotic healing in another? In this study, we use a model of mammalian tissue regeneration, the African spiny mouse (Acomys cahirinus) to investigate macrophage activity during regeneration. Acomys are able to regenerate tissue of the external ear pinnae whereas the common lab mouse (Mus musculus) forms a scar. We hypothesized that unique macrophage activity in Acomys promotes regeneration over scar formation. To test this hypothesis, we assessed the ability of macrophages from both species to respond to classic stimulation paradigms in vitro. Analyzing gene expression and cytokine production from macrophages we found species-specific pro-inflammatory profiles. To test how ear fibroblasts respond to these species-specific macrophage profiles we analyzed changes in extracellular matrix production by Acomys and Mus fibroblasts cultured with macrophage-conditioned media. Our results suggest that pro-inflammatory macrophages from Acomys are able to reduce collagen production and increase matrix metalloproteinase production in ear fibroblasts from both species. Finally, we quantify macrophage phenotypes in vivo and observe specific differences in spatiotemporal localization of macrophage subtypes that respond to each injury. Together our findings suggest the existence of a unique pro-inflammatory macrophage in Acomys that can reduce scar matrix production by fibroblasts and enhance the production of remodeling enzymes important for regeneration. Opposing action of Hedgehog and Insulin signaling controls proliferation and autophagy to determine Follicle Stem Cell Lifespan Tanu Singh1,2, Eric Lee1, Tiffiney Hartman1, Dara Ruiz-Whalen1, Alana O'Reilly1 1Fox Chase Cancer Center, USA; 2Drexel University College of Medicine, USA Egg production declines with age in many species, a process linked with stem cell loss. Diet-dependent signaling has emerged as critical for stem cell maintenance during aging. Follicle Stem Cells (FSCs) in the Drosophila ovary are exquisitely responsive to diet-induced signals including Hedgehog (Hh) and Insulin (IIS), entering quiescence in the absence of nutrients and initiating proliferation rapidly upon feeding. Although highly proliferative FSCs generally exhibit extended lifespan, we find that constitutive Hh signaling drives FSC loss and premature sterility despite high proliferative rates. This occurs due to Hh- mediated induction of autophagy in FSCs via a novel Ptc-dependent, Smo- independent mechanism. Hh-dependent