DOCSLIB.ORG

Independent Helix-Loop-Helix Proteins

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Independent Helix-Loop-Helix Proteins Proc. Natl. Acad. Sci. USA Vol. 89, pp. 8731-8735, September 1992 Genetics The Enhancer of split [E(spt)] locus of Drosophila encodes seven independent helix-loop-helix proteins CHRISTOS DELIDAKIS AND SPYROS ARTAVANIS-TSAKONAS* Departments of Cell Biology and Biology, Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale University, New Haven, CT 06536-0812 Communicated by Gerald M. Rubin, May 13, 1992 ABSTRACT The E(spl) locus is thought to participate in a function is mediated by two classes of closely linked genes cell interaction mechanism that controls the choice ofmany cell (16). One class corresponds to a cluster ofthree bHLH genes, fates during Drosophila development, including the segregation m5, m7, and m8, first described by Klambt et al. (17); the of neural precursors. Previous studies have demonstrated that other is a single-copy gene, m9/10, encoding a nuclear E(spl) is defined by two groups ofclosely related transcripts, (i) protein containing repeated motifs first identified in the /3 a cluster of three transcripts encoding proteins bearing a subunit of guanine nucleotide-binding proteins (G proteins) helix-oop-helix (HLH) motif and (it) a single-copy gene en- (18, 19). We found that the overall copy number of the E(spl) coding a nuclear protein containing repeated motifs first iden- HLH genes is central in establishing the neural-epidermal tified in the .3 subunit of guanine nucleotide-binding proteins. dichotomy, as gradual reduction in their copy number leads Both groups interact genetically with the Notch locus, which to progressively greater extents of neural hypertrophy (see codes for a transmembrane protein. We report the structure of also ref. 15). Modification of m9/10 copy numbers, on the four additional HLH-encoding genes that reside in the E(spl) other hand, shows less pronounced phenotypic effects. The complex and provide evidence that we have now identified all presence ofthe HLH motifin E(spl) products and the fact that the remaining members of the E(spl) HLH cluster. HLH proteins can form heterooligomers suggest that they serve as transcriptional regulators of the ASC genes, maybe The differentiation of neural and epidermal precursors from even through direct interactions with ASC proteins. the neurogenic regions of the early Drosophila embryo Prior genetic analysis has shown that at least m7 and m8 are involves a process of intercellular communication. Genetic dispensable, suggesting functional redundancy among E(spl) disruption of this signaling mechanism results in neural HLH genes (16). We have further shown that proximal to the hyperplasia accompanied by epidermal hypoplasia in accor- characterized cluster there must be at least one more E(spl) dance with the model that a developing neuroblast sends an HLH gene with properties similar to those ofmS, m7, and m8. inhibitory signal to its neighbors to prevent them from Here we present the localization and characterization of four acquiring the neural fate (1). Characterization of the genes additional E(spl) HLH transcription units, which correspond implicated in this communication mechanism shows highly to this genetically identified proximal component and appear pleiotropic effects on cell fate choices throughout develop- to represent all the remaining members of the E(spl) HLH ment. A central element of this mechanism is Notch, which cluster.t codes for a transmembrane protein. Several studies have identified genes that can interact with Notch and are there- MATERIALS AND METHODS fore thought to be part of the same interaction mechanism. These components include transmembrane, cytoplasmic, DNA Hybridization and Sequence Analysis. DNA restric- and nuclear proteins encoded by the neurogenic genes Delta, tion digests were size-separated by horizontal agarose gel mastermind, and E(spl), as well as Serrate and deltex (2, 3). electrophoresis and blotted to Zeta-Probe nylon membranes This group of genes has been collectively termed the Notch (Bio-Rad) in 0.4 M NaOH (20). The hybridization buffer was group (3, 4). 0.5 M sodium phosphate, pH 7.2/1 mM Na2 EDTA/5% SDS The ability of a cell in the neurogenic ectoderm to acquire (contributing 170 mM Na+)/1% (wt/vol) bovine serum albu- the neural fate depends on the expression of one of the min (fraction V; Sigma). The wash buffer consisted of40 mM "proneural" genes (5), such as those coded for by the sodium phosphate, pH 7.2/1 mM Na2EDTA/1% SDS (34 achaete-scute (ac-sc) complex (ASC) (6). Expression of mM Na+). High-stringency washes were at 68-70°C. To these genes in the precursors of adult sensory organs is determine the optimal low-stringency conditions, we hybrid- initially diffuse over a cluster of cells. Eventually, only one ized duplicate filters containing E(spl)-region subclones with cell, the future neuroblast, continues to express high levels of m5 or m7 probes at 50°C (three filters with each probe). We ASC products (7-9). The situation is probably similar in the subsequently washed each of the three filters at 70°C, 50°C, embryonic central nervous system (10, 11). Possibly the or room temperature. Genomic or cDNA fragments were neurogenic genes function in refining the ASC expression subcloned into M13 mpl8 and/or mpl9 for dideoxy sequenc- pattern. ASC genes encode nuclear DNA-binding proteins ing using the Sequenase kit (United States Biochemical) and bearing a basic-helix-loop-helix (bHLH) motif(12-14). They a combination of synthetic oligonucleotide primers. Se- have, therefore, been implicated as transcriptional activators quence analysis was performed using the MacVector soft- of neuroblast-specific genes. ware (IBI) for the Macintosh computer. Previous studies have implicated several independent tran- PCR Detection of E(spl) HLH Genes. To obtain primers scripts in the function of the E(sp() locus, and thus the locus recognizing all known E(spl) HLH genes, we used the regions is referred to as the Enhancer of split complex (15). Our molecular genetic analysis ofthe E(spl) locus revealed that its Abbreviations: ASC, achaete-scute complex; bHLH, basic-helix- loop-helix. *To whom reprint requests should be addressed. The publication costs of this article were defrayed in part by page charge tThe sequences reported in this paper have been deposited in the payment. This article must therefore be hereby marked "advertisement" GenBank data base (accession nos. M96165-M96168 for m3, mA, in accordance with 18 U.S.C. §1734 solely to indicate this fact. mB, and mC, respectively). 8731 Downloaded by guest on September 30, 2021 8732 Genetics: Delidakis and Artavanis-Tsakonas Proc. Natl. Acad. Sci. USA 89 (1992) of highest sequence conservation. The ARIN primer corre- E H sponds to the sequence spanning the basic/helix Ijunction of mA, mB, and mC (see also Fig. 4). m8, m7, mS, m3, FIG. 2. The 100-bp products de- Consensus: GCC-AGGAT -AAC-AAG-TGC-CTG-GAC -12.O} rived from a PCR with total Drosoph- 8.5 -4' ila genomic DNA as template and Translation: A R M/I N K/L C/Y L D 7.5 -_' 450C as reannealing temperature were used to probe a Southern blot of ge- This consensus sequence was synthesized. The correspond- 5.2 -_' 5.2 nomic DNA digested with EcoRI ing sequence from the related HLH gene hairy (see Results (lane E) or HindIll (lane H). The 100-bp species is diagnostic of the and Discussion) contains six mismatches: GCC-CGT-ATT- 4.1 -_' AAC-AAC-TGT-CTC-AAT. 4-3.6 presence of an E(spt HLH gene (see 3.4 .-- text). Sizes of the fragments (kb) de- The EKAD primer corresponds to the helix II region ofm8, tected are shown. By comparison to m7, m5, m3, mA, mB, and mC (see also Fig. 4). the E(spt) restriction map (Fig. 1), they all correspond to E(spl) HLH Consensus: Tc-_GAC GAAGGCA ~C_GAGCCATGCTG-GAGA 2.1 genes. Specifically, for the EcoRI di- Translation: T T gest, 8.5 kb corresponds to m5 and mC (identically sized fragments), 7.5 M/F/L E/D K A D/E I/M L E 1. 5-p5 - kb to m3, 5.2 kb to m8, 4.1 kb to mB, reverse complement of the above consensus was syn- 3.4 kb to mA, and 1.55 kb to m7. For The the HindIII digest, 12 kb corresponds thesized (EKAD primer). The corresponding hairy sequence to m7 plus m8, 5.8 kb to mA, 5.2 kb to contains only two mismatches: (T)TG-GAA-AAG-GCC- m5, 3.6 kb to m3, 2.1 kb to mB, and GAC-AT_-CTG-GAG. 1.5 kb to mC. The PCR cycle was 1 min at 940C, 1 min at 450C, 1 min at 720C; 30 cycles were performed. The same reactions were Under these conditions, both mS- and m7-containing repeated with annealing at 370C. Primers were used at 1 AM probes were able to detect all mS, m7, and m8 fragments final concentration and dNTPs at 0.2 mM each. Templates above background (data not shown). We used the same two were plasmid or cosmid clones from the E(spl) region, -1 ng probes on blots containing restriction enzyme digests of per 50-1.l reaction mixture. Total genomic DNA (40 ng) was plasmid or cosmid clones spanning a total of81 kilobases (kb) also used for the reactions at 450C annealing temperature. of contiguous genomic DNA. In addition to the expected restriction fragments corresponding to mS, m7, and m8, we detected strong cross-hybridization signals with four more RESULTS AND DISCUSSION restriction fragments. Fig. 1 shows a restriction map of the The neurogenic function of the locus is provided to a large region analyzed and the fragments exhibiting cross- extent by a group ofhomologous genes (m5, m7, and m8) with hybridization to m5 and m7.
Load more

Recommended publications
  • Investigating the Co-Regulatory Role of Midline and Extramacrochaetae in Regulating Eye Development and Vision in Drosophila Melanogaster
    The University of Southern Mississippi The Aquila Digital Community Honors Theses Honors College Spring 5-2014 Investigating the Co-Regulatory Role of Midline and Extramacrochaetae In Regulating Eye Development and Vision in Drosophila melanogaster Lillian M. Forstall University of Southern Mississippi Follow this and additional works at: https://aquila.usm.edu/honors_theses Part of the Developmental Biology Commons Recommended Citation Forstall, Lillian M., "Investigating the Co-Regulatory Role of Midline and Extramacrochaetae In Regulating Eye Development and Vision in Drosophila melanogaster" (2014). Honors Theses. 236. https://aquila.usm.edu/honors_theses/236 This Honors College Thesis is brought to you for free and open access by the Honors College at The Aquila Digital Community. It has been accepted for inclusion in Honors Theses by an authorized administrator of The Aquila Digital Community. For more information, please contact [email protected]. The University of Southern Mississippi Investigating the Co-Regulatory Role of midline and extramacrochaetae In Regulating Eye Development and Vision in Drosophila melanogaster by Lillian Forstall A Thesis Submitted to the Honors College of The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in the Department of Biological Sciences May 2014 ii Approved by _________________________________ Dr. Sandra Leal, Ph.D., Thesis Adviser Assistant Professor of Biology _________________________________ Dr. Shiao Wang, Ph.D., Interim Chair Department of Biological Sciences _________________________________ Dr. David R. Davies, Ph.D., Dean Honors College iii Abstract The Honors thesis research focused on the roles of extramacrochaetae and midline in regulating eye development and the vision of Drosophila melanogaster.
    [Show full text]
  • Regulation of the Drosophila ID Protein Extra Macrochaetae by Proneural Dimerization Partners Ke Li1†, Nicholas E Baker1,2,3*
    RESEARCH ARTICLE Regulation of the Drosophila ID protein Extra macrochaetae by proneural dimerization partners Ke Li1†, Nicholas E Baker1,2,3* 1Department of Genetics, Albert Einstein College of Medicine, Bronx, United States; 2Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, United States; 3Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, United States Abstract Proneural bHLH proteins are transcriptional regulators of neural fate specification. Extra macrochaetae (Emc) forms inactive heterodimers with both proneural bHLH proteins and their bHLH partners (represented in Drosophila by Daughterless). It is generally thought that varying levels of Emc define a prepattern that determines where proneural bHLH genes can be effective. We report that instead it is the bHLH proteins that determine the pattern of Emc levels. Daughterless level sets Emc protein levels in most cells, apparently by stabilizing Emc in heterodimers. Emc is destabilized in proneural regions by local competition for heterodimer formation by proneural bHLH proteins including Atonal or AS-C proteins. Reflecting this post- translational control through protein stability, uniform emc transcription is sufficient for almost normal patterns of neurogenesis. Protein stability regulated by exchanges between bHLH protein *For correspondence: dimers could be a feature of bHLH-mediated developmental events. [email protected] DOI: https://doi.org/10.7554/eLife.33967.001 Present address: †Howard Hughes Medical Institute, Department of Physiology, University of California, San Introduction Francisco, San Francisco, United Proneural bHLH genes play a fundamental role in neurogenesis. Genes from Drosophila such as States atonal (ato) and genes of the Achaete-Scute gene complex (AS-C) define the proneural regions that Competing interests: The have the potential for neural fate (Baker and Brown, 2018; Bertrand et al., 2002; Go´mez- authors declare that no Skarmeta et al., 2003).
    [Show full text]
  • Cell Proliferation Control by Notch Signalling During Imaginal Discs
    Published online: 2021-05-10 Manuscript submitted to: Volume 2, Issue 1, 70-96. AIMS Genetics DOI: 10.3934/genet.2015.1.70 Received date 13 November 2014, Accepted date 25 January 2015, Published date 5 February 2015 Review Cell proliferation control by Notch signalling during imaginal discs development in Drosophila Carlos Estella 1 and Antonio Baonza 2, * 1 Departamento de Biología Molecular and Centro de Biología Molecular SeveroOchoa, Universidad Autónoma de Madrid (UAM), Madrid, Spain 2 Centro de Biología Molecular Severo Ochoa (CSIC/UAM) c/Nicolás Cabrera 1, 28049, Madrid, Spain * Correspondence: Email: [email protected]; Tel: 0034 914974129; Fax: 0034 914978632. Abstract: The Notch signalling pathway is evolutionary conserved and participates in numerous developmental processes, including the control of cell proliferation. However, Notch signalling can promote or restrain cell division depending on the developmental context, as has been observed in human cancer where Notch can function as a tumor suppressor or an oncogene. Thus, the outcome of Notch signalling can be influenced by the cross-talk between Notch and other signalling pathways. The use of model organisms such as Drosophila has been proven to be very valuable to understand the developmental role of the Notch pathway in different tissues and its relationship with other signalling pathways during cell proliferation control. Here we review recent studies in Drosophila that shed light in the developmental control of cell proliferation by the Notch pathway in different contexts such as the eye, wing and leg imaginal discs. We also discuss the autonomous and non-autonomous effects of the Notch pathway on cell proliferation and its interactions with different signalling pathways.
    [Show full text]
  • Atrophin Controls Developmental Signaling Pathways Via Interactions
    RESEARCH ARTICLE Atrophin controls developmental signaling pathways via interactions with Trithorax-like Kelvin Yeung1,2, Ann Boija3, Edvin Karlsson4,5, Per-Henrik Holmqvist3, Yonit Tsatskis1,2, Ilaria Nisoli6†, Damian Yap7,8, Alireza Lorzadeh9,10,11, Michelle Moksa9,10,11, Martin Hirst9,10,11, Samuel Aparicio7,8, Manolis Fanto6, Per Stenberg4,5, Mattias Mannervik3*, Helen McNeill1,2* 1Department of Molecular Genetics, University of Toronto, Toronto, Canada; 2Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada; 3Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden; 4Department of Molecular Biology, Umea˚ University, Umea˚ , Sweden; 5Division of CBRN Security and Defence, FOI-Swedish Defence Research Agency, Umea˚ , Sweden; 6Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King’s College London, London, United Kingdom; 7Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, Canada; 8Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada; 9Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada; 10Michael Smith Laboratories, Vancouver, Canada; 11Canada’s *For correspondence: mattias. [email protected] (MMa); mcneill@ Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada lunenfeld.ca (HM) Present address: †Division of Infection and Immunity, Abstract Mutations in human Atrophin1, a transcriptional
    [Show full text]
  • Gene Expression in Wild-Type and Myod-Null Satellite Cells: Regulation of Activation, Proliferation, and Myogenesis
    Gene expression in wild-type and MyoD-null satellite cells: regulation of activation, proliferation, and myogenesis Thesis by Dawn D. W. Cornelison In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 1998 (Submitted May 22, 1998) 11 © 1998 Dawn D.W. Cornelison All rights reserved. 11l Acknowledgements I would like to thank all of the people in and out of Caltech who have influenced my graduate education, in particular: First, my parents, for never thinking there was anything I couldn't do; and if they occasionally thought I shouldn't, for not saying so out loud. Drs. Andy and Toni Smolen, for showing me how much fun it is. Katherine Woo, for her friendship, support, and inspiration, not to mention her generosity with her excellent microscopy skills and occasional babysitting. The members of my committee, for their support and enthusiasm, particularly Scott Fraser, for a vote of confidence when one was most needed. The members of the Wold lab, past and present, especially Kyuson Yun, Ardem Patapoutian, Sonya Palmer and Marie Csete. I have been incredibly lucky to have been surrounded by labmates whom I like as people as much as I respect as scientists. The members and associates of the ARCS Foundation, for their generous and much-appreciated support for many years. My daughters, Ceili, Abagael, and Aidan, for being very understanding about having a mad scientist for a mom. Last and most, to Paul, for all the reasons he knows and a few that he doesn't, I dedicate this work with love and gratitude.
    [Show full text]
  • The Drosophila Extramacrochaetae Protein Antagonizes Sequence-Specific DNA Binding by Daughterless/Achaete-Scute Protein Complexes
    Development 113, 245-255 (1991) 245 Printed in Great Britain © The Company of Biologists Limited 1991 The Drosophila extramacrochaetae protein antagonizes sequence-specific DNA binding by daughterless/achaete-scute protein complexes MARK VAN DOREN, HILARY M. ELLIS* and JAMES W. POSAKONYf Department of Biology and Center for Molecular Genetics, University of California San Diego, LaJolla, CA 92093-0322, USA * Present address: Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, USA t Corresponding author Summary In Drosophila, a group of regulatory proteins of the of emc. Under the conditions of our experiments, the emc helix-loop-helix (HLH) class play an essential role in protein, but not the h protein, is able to antagonize conferring upon cells in the developing adult epidermis specifically the in vitro DNA-binding activity of da/AS-C the competence to give rise to sensory organs. Proteins and putative da/da protein complexes. We interpret encoded by the daughterless (da) gene and three genes of these results as follows: the heterodimerization capacity the achaete-scute complex (AS-C) act positively in the of the emc protein (conferred by its HLH domain) allows determination of the sensory organ precursor cell fate, it to act in vivo as a competitive inhibitor of the while the extramacrochaetae (emc) and hairy (h) gene formation of functional DNA-binding protein complexes products act as negative regulators. In the region by the da and AS-C proteins, thereby reducing the upstream of the achaete gene of the AS-C, we have effective level of their transcriptional regulatory activity identified three 'E box' consensus sequences that are within the cell.
    [Show full text]
  • Extramacrochaete Promotes Branch and Bouton Number Via the Sequestration Of
    bioRxiv preprint doi: https://doi.org/10.1101/686014; this version posted June 28, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. Title: Extramacrochaete promotes branch and bouton number via the sequestration of Daughterless in the cytoplasm of neurons. Authors: Edward A. Waddell1, Jennifer M. Viveiros1, Erin L. Robinson1, Michal A. Sharoni1, Nina K. Latcheva1, and Daniel R. Marenda1*, 2* Addresses: 1Department of Biology, Drexel University, Philadelphia, PA, USA; 2Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA *Correspondence: Daniel R. Marenda, Department of Biology, Drexel University, 3141 Chestnut St., Philadelphia, PA 19104. Email: [email protected]; Short Title: Emc sequesters Da in the cytoplasm Key Words: Daughterless; TCF4; NMJ; proneural; bHLH; Pitt-Hopkins; schizophrenia; EMC; ID; HLH 1 bioRxiv preprint doi: https://doi.org/10.1101/686014; this version posted June 28, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. Abstract The class I basic Helix Loop Helix (bHLH) proteins are highly conserved transcription factors that are ubiquitously expressed. A wealth of literature on class I bHLH proteins have shown that these proteins must homodimerize or heterodimerize with tissue specific HLH proteins in order to bind DNA at E box (CANNTG) consensus sequences to control tissue specific transcription.
    [Show full text]
  • 7648.Full.Pdf
    The Journal of Neuroscience, October 15, 2000, 20(20):7648–7656 Evidence That Helix-Loop-Helix Proteins Collaborate with Retinoblastoma Tumor Suppressor Protein to Regulate Cortical Neurogenesis Jean G. Toma, Hiba El-Bizri, Fanie Barnabe´ -Heider, Raquel Aloyz, and Freda D. Miller Center for Neuronal Survival, Montreal Neurological Institute, Montreal, Canada H3A 2B4 The retinoblastoma tumor suppressor protein (pRb) family is phenotypes were rescued by coexpression of a constitutively essential for cortical progenitors to exit the cell cycle and survive. activated pRb mutant. In contrast, Id2 overexpression in post- In this report, we test the hypothesis that pRb collaborates with mitotic cortical neurons affected neither neuronal gene expres- basic helix-loop-helix (bHLH) transcription factors to regulate sion nor survival. Thus, pRb collaborates with HLHs to ensure the cortical neurogenesis, taking advantage of the naturally occur- coordinate induction of terminal mitosis and neuronal gene ex- ring dominant-inhibitory HLH protein Id2. Overexpression of Id2 pression as cortical progenitors become neurons. in cortical progenitors completely inhibited the induction of Key words: neurogenesis; Id2; pRb; bHLH transcription fac- neuron-specific genes and led to apoptosis, presumably as a tors; cortical development; neuronal gene expression; ␣-tubulin; consequence of conflicting differentiation signals. Both of these neural progenitor cells; neurofilaments; apoptosis During embryogenesis, cycling neural progenitor cells in the ven- In particular, in the PNS, bHLHs such as Mash-1 (Johnson et al., tricular zones of the CNS commit to a neuronal fate, and as a 1990) and the neurogenins (Ma et al., 1996; Sommer et al., 1996) consequence of that decision, coordinately undergo terminal mito- regulate the genesis of defined neuronal populations (Guillemot et sis and induce early, neuron-specific genes.
    [Show full text]
  • Topic 3.0 Genetic Determination of Sex 3.1 Drosophila 3.2 Human
    April 2020 ZOB 603: Genetic and Cell Biology Topic 3.0 Genetic Determination of Sex 3.1 Drosophila 3.2 Human Developed By – Dr. Ganesh Kumar Maurya Assistant Professor (Zoology) MMV, BHU Sex & its Determination • The word SEX is derived from the Latin word sexus meaning separation. • Sex is the morphological ,physiological & behavioural difference observed between egg and sperm producing organisms. WHAT IS SEX DETERMINATION? - It refers to the hormonal, environmental and genetical especially molecular mechanism that make an organism either male or female. - It determines the development of sexual characteristics in an organism. Sex Determination in Drosophila - In Drosophila, sex determination is achieved by Genic balance mechanism (given by Calvin Bridges , 1926)i.e. a balance of female determinants on the X chromosome and male determinants on the autosomes. - Ratio of X chromosomes: haploid sets of autosomes (X:A) determine the sex. X chromosome = Female producing effects Autosomes = Male producing effects Y Chromosome= Fertility factor in male required for sperm formation but not in sex determination. X:A ratio Female = 1.0 (2X:2A) Male = 0.5 (1x:2A) 0.5 < X:A < 1.0 = intersex XO Drosophila are sterile males. Gynandromorphs Gynandromorphs are animals in which certain regions of the body are male and other regions are female. Examples - Drosophila and certain other insects - This can happen when an X chromosome is lost from one embryonic nucleus. The cells descended from that cell, instead of being XX (female), are XO (male) - In Insects, each cell makes its own sexual "decision" because they lack sex hormones to modulate such events.
    [Show full text]
  • The Bristle Patterning Genes Hairy and Extramacrochaetae Regulate the Development of Structures Required for Flight in Diptera
    The bristle patterning genes hairy and extramacrochaetae regulate the development of structures required for flight in Diptera Article (Published Version) Costa, Marta, Calleja, Manuel, Alonso, Claudio R and Simpson, Pat (2014) The bristle patterning genes hairy and extramacrochaetae regulate the development of structures required for flight in Diptera. Developmental Biology, 388 (2). pp. 205-215. ISSN 0012-1606 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/59194/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk Developmental Biology 388 (2014) 205–215 Contents lists available at ScienceDirect Developmental Biology journal homepage: www.elsevier.com/locate/developmentalbiology Evolution of Developmental Control Mechanisms The bristle patterning genes hairy and extramacrochaetae regulate the development of structures required for flight in Diptera Marta Costa a, Manuel Calleja b, Claudio R.
    [Show full text]
  • Proneural Clusters of Achaete-Scute Expression and the Generation of Sensory Organs in the Drosophila Imaginal Wing Disc
    Downloaded from genesdev.cshlp.org on September 24, 2021 - Published by Cold Spring Harbor Laboratory Press Proneural clusters of achaete-scute expression and the generation of sensory organs in the Drosophila imaginal wing disc Pilar Cubas, Jos6-Fdlix de Cells, Sonsoles Campuzano, and Juan Modolell Centro de Biologia Molecular, Consejo Superior de Investigaciones Cientificas and Universidad Aut6noma de Madrid, 28049 Madrid, Spain The proneural genes achaete (ac) and scute (sc) confer to Drosophila epidermal cells the ability to become sensory mother cells (SMCs). In imaginal discs, ac-sc are expressed in groups of cells, the proneural clusters, which are thought to delimit the areas where SMCs arise. We have visualized with the resolution of single cells the initial stages of sensory organ development by following the evolving pattern of proneural clusters and the emergence of SMCs. At reproducible positions within clusters, a small number of cells accumulate increased amounts of ac-sc protein. Subsequently, one of these cells, the SMC, accumulates the highest amount. Later, at least some SMCs become surrounded by cells with reduced ac-sc expression, a phenomenon probably related to lateral inhibition. Genetic mosaic analyses of cells with different doses of ac-sc genes, the sc expression in sc mutants, and the above findings show that the levels of ac-sc products are most important for SMC singling-out and SMC state maintenance. These products do not intervene in the differentiation of SMC descendants. The extramacrochaetae gene, an antagonist of proneural genes, negatively regulates sc expression, probably by interfering with activators of this gene. [Key Words: Sensory organ precursors; achaete; scute; pattern formation; proneural cluster] Received January 15, 1991; revised version accepted March 5, 1991.
    [Show full text]
  • Negative Regulation of Proneural Gene Activity: Hairy Is a Direct Transcriptional Repressor of Achaete
    Downloaded from genesdev.cshlp.org on October 7, 2021 - Published by Cold Spring Harbor Laboratory Press Negative regulation of proneural gene activity: hairy is a direct transcriptional repressor of achaete Mark Van Doren/ Adina M. Bailey, Joan Esnayia, Kekoa Ede, and James W. Posakony^ Department of Biology and Center for Molecular Genetics, University of California San Diego, La Jolla, California 92093-0322 USA hairy (A) acts as a negative regulator in both embryonic segmentation and adult peripheral nervous system (PNS) development in Drosophila. Here, we demonstrate that h, a basic-helix-loop-helix (bHLH) protein, is a sequence-specific DNA-binding protein and transcriptional repressor. We identify the proneural gene acbaete (flc) as a direct downstream target of h regulation in vivo. Mutation of a single, evolutionarily conserved, high-affinity h binding site in the upstream region of ac results in the appearance of ectopic sensory organs in adult flies, in a pattern that strongly resembles the phenotype of b mutants. This indicates that direct repression of ac by h plays an essential role in pattern formation in the PNS. Our results demonstrate that HLH proteins negatively regulate ac transcription by at least two distinct mechanisms. [Key Words: Diosophila-, neurogenesis; peripheral nervous system; transcriptional repression; helix-loop-helix; negative regulation] Received August 2, 1994; revised version accepted September 21, 1994. The sensory organs that comprise the adult peripheral as hairy [h], extramacrochaetae [emc], and pannier [pnr] nervous system (PNS) of Drosophila offer an excellent leads to ectopic ac-sc expression and ectopic sensory system for the study of pattern formation during devel­ organs (Mohr 1918, as cited in Lindsley and Zimm 1992; opment.
    [Show full text]