1
|
Reddy Onteddu V, Bhattacharya A, Baker NE. The Id protein Extramacrochaetae restrains the E protein Daughterless to regulate Notch, Rap1, and Sevenless within the R7 equivalence group of the Drosophila eye. Biol Open 2024; 13:bio060124. [PMID: 39041866 PMCID: PMC11360143 DOI: 10.1242/bio.060124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 07/15/2024] [Indexed: 07/24/2024] Open
Abstract
The Drosophila Id gene extramacrochaetae (emc) is required during Drosophila eye development for proper cell fate specification within the R7 equivalence group. Without emc, R7 cells develop like R1/6 cells, and there are delays and deficits in differentiation of non-neuronal cone cells. Although emc encodes an Inhibitor of DNA-binding (Id) protein that is known to antagonize proneural bHLH protein function, no proneural gene is known for R7 or cone cell fates. These fates are also independent of daughterless (da), which encodes the ubiquitous E protein heterodimer partner of proneural bHLH proteins. We report here that the effects of emc mutations disappear in the absence of da, and are partially mimicked by forced expression of Da dimers, indicating that emc normally restrains da from interfering with R7 and cone cell specification, as occurs in emc mutants. emc, and da, regulate three known contributors to R7 fate, which are Notch signaling, Rap1, and Sevenless. R7 specification is partially restored to emc mutant cells by mutation of RapGap1, confirming that Rap1 activity, in addition to Notch activity, is a critical target of emc. These findings exemplify how mutations of an Id protein gene can affect processes that do not require any bHLH protein, by restraining Da activity within physiological bounds.
Collapse
Affiliation(s)
- Venkateswara Reddy Onteddu
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461,USA
| | - Abhishek Bhattacharya
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461,USA
| | - Nicholas E. Baker
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461,USA
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461,USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461,USA
| |
Collapse
|
2
|
Nair S, Baker NE. Extramacrochaetae regulates Notch signaling in the Drosophila eye through non-apoptotic caspase activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.04.560841. [PMID: 39131389 PMCID: PMC11312471 DOI: 10.1101/2023.10.04.560841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Many cell fate decisions are determined transcriptionally. Accordingly, some fate specification is prevented by Inhibitor of DNA binding (Id) proteins that interfere with DNA binding by master regulatory transcription factors. We show that the Drosophila Id protein Extra macrochaetae (Emc) also affect developmental decisions by regulating caspase activity. Emc, which prevents proneural bHLH transcription factors from specifying neural cell fate, also prevents homodimerization of another bHLH protein, Daughterless (Da), and thereby maintains expression of the Death-Associated Inhibitor of Apoptosis (diap1) gene. We found that multiple effects of emc mutations on cell growth and on eye development were all caused by reduced Diap1 levels and corresponding activation of caspases. These effects included acceleration of the morphogenetic furrow, failure of R7 photoreceptor cell specification, and delayed differentiation of non-neuronal cone cells. Within emc mutant clones, Notch signaling was elevated in the morphogenetic furrow, increasing morphogenetic furrow speed. This was associated with caspase-dependent increase in levels of Delta protein, the transmembrane ligand for Notch. Posterior to the morphogenetic furrow, elevated Delta cis-inhibited Notch signaling that was required for R7 specification and cone cell differentiation. Thus, emc mutations reveal the importance of restraining caspase activity even in non-apoptotic cells to prevent abnormal development, in the Drosophila eye through effects on Notch signaling.
Collapse
Affiliation(s)
- Sudershana Nair
- Department of Genetics Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx NY 10461
- Present address: Department of Neuroscience and Physiology NYU School of Medicine 435 East 30 St New York, NY
| | - Nicholas E Baker
- Department of Genetics Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx NY 10461
- Department of Developmental and Molecular Biology Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx NY 10461
- Department of Ophthalmology and Visual Sciences Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx NY 10461
- Present address: Department of Microbiology and Molecular Genetics University of California, Irvine 2011 Biological Sciences 3 Irvine, CA 92697-2300
| |
Collapse
|
3
|
Johnson RI. Hexagonal patterning of the Drosophila eye. Dev Biol 2021; 478:173-182. [PMID: 34245727 DOI: 10.1016/j.ydbio.2021.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 10/24/2022]
Abstract
A complex network of transcription factor interactions propagates across the larval eye disc to establish columns of evenly-spaced R8 precursor cells, the founding cells of Drosophila ommatidia. After the recruitment of additional photoreceptors to each ommatidium, the surrounding cells are organized into their stereotypical pattern during pupal development. These support cells - comprised of pigment and cone cells - are patterned to encapsulate the photoreceptors and separate ommatidia with an hexagonal honeycomb lattice. Since the proteins and processes essential for correct eye patterning are conserved, elucidating how these function and change during Drosophila eye patterning can substantially advance our understanding of transcription factor and signaling networks, cytoskeletal structures, adhesion complexes, and the biophysical properties of complex tissues during their morphogenesis. Our understanding of many of these aspects of Drosophila eye patterning is largely descriptive. Many important questions, especially relating to the regulation and integration of cellular events, remain.
Collapse
Affiliation(s)
- Ruth I Johnson
- Biology Department, Wesleyan University, 52 Lawn Avenue, Middletown, CT, USA.
| |
Collapse
|
4
|
Tamberg L, Jaago M, Säälik K, Sirp A, Tuvikene J, Shubina A, Kiir CS, Nurm K, Sepp M, Timmusk T, Palgi M. Daughterless, the Drosophila orthologue of TCF4, is required for associative learning and maintenance of the synaptic proteome. Dis Model Mech 2020; 13:dmm042747. [PMID: 32641419 PMCID: PMC7406316 DOI: 10.1242/dmm.042747] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 06/24/2020] [Indexed: 12/11/2022] Open
Abstract
Mammalian transcription factor 4 (TCF4) has been linked to schizophrenia and intellectual disabilities, such as Pitt-Hopkins syndrome (PTHS). Here, we show that similarly to mammalian TCF4, fruit fly orthologue Daughterless (Da) is expressed widely in the Drosophila brain. Furthermore, silencing of da, using several central nervous system-specific Gal4 driver lines, impairs appetitive associative learning of the larvae and leads to decreased levels of the synaptic proteins Synapsin (Syn) and Discs large 1 (Dlg1), suggesting the involvement of Da in memory formation. Here, we demonstrate that Syn and dlg1 are direct target genes of Da in adult Drosophila heads, as Da binds to the regulatory regions of these genes and the modulation of Da levels alter the levels of Syn and dlg1 mRNA. Silencing of da also affects negative geotaxis of the adult flies, suggesting the impairment of locomotor function. Overall, our findings suggest that Da regulates Drosophila larval memory and adult negative geotaxis, possibly via its synaptic target genes Syn and dlg1 These behavioural phenotypes can be further used as a PTHS model to screen for therapeutics.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Laura Tamberg
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Mariliis Jaago
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
- Protobios LLC, Mäealuse 4, Tallinn 12618, Estonia
| | - Kristi Säälik
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Alex Sirp
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Jürgen Tuvikene
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
- Protobios LLC, Mäealuse 4, Tallinn 12618, Estonia
| | - Anastassia Shubina
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Carl Sander Kiir
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Kaja Nurm
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Mari Sepp
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| | - Tõnis Timmusk
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
- Protobios LLC, Mäealuse 4, Tallinn 12618, Estonia
| | - Mari Palgi
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
| |
Collapse
|
5
|
Ali S, Signor SA, Kozlov K, Nuzhdin SV. Novel approach to quantitative spatial gene expression uncovers genetic stochasticity in the developing Drosophila eye. Evol Dev 2019; 21:157-171. [PMID: 30756455 DOI: 10.1111/ede.12283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Robustness in development allows for the accumulation of genetically based variation in expression. However, this variation is usually examined in response to large perturbations, and examination of this variation has been limited to being spatial, or quantitative, but because of technical restrictions not both. Here we bridge these gaps by investigating replicated quantitative spatial gene expression using rigorous statistical models, in different genotypes, sexes, and species (Drosophila melanogaster and D. simulans). Using this type of quantitative approach with molecular developmental data allows for comparison among conditions, such as different genetic backgrounds. We apply this approach to the morphogenetic furrow, a wave of differentiation that patterns the developing eye disc. Within the morphogenetic furrow, we focus on four genes, hairy, atonal, hedgehog, and Delta. Hybridization chain reaction quantitatively measures spatial gene expression, co-staining for all four genes simultaneously. We find considerable variation in the spatial expression pattern of these genes in the eye between species, genotypes, and sexes. We also find that there has been evolution of the regulatory relationship between these genes, and that their spatial interrelationships have evolved between species. This variation has no phenotypic effect, and could be buffered by network thresholds or compensation from other genes. Both of these mechanisms could potentially be contributing to long term developmental systems drift.
Collapse
Affiliation(s)
- Sammi Ali
- Molecular and Computational Biology, University of Southern California, Los Angeles, California
| | - Sarah A Signor
- Molecular and Computational Biology, University of Southern California, Los Angeles, California
| | - Konstantin Kozlov
- Department of Applied Mathematics, St. Petersburg State Polytechnic University, St. Petersburg, Russia
| | - Sergey V Nuzhdin
- Molecular and Computational Biology, University of Southern California, Los Angeles, California.,Department of Applied Mathematics, St. Petersburg State Polytechnic University, St. Petersburg, Russia
| |
Collapse
|
6
|
CtBP represses Dpp-dependent Mad activation during Drosophila eye development. Dev Biol 2018; 442:188-198. [PMID: 30031756 DOI: 10.1016/j.ydbio.2018.07.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/05/2018] [Accepted: 07/18/2018] [Indexed: 12/13/2022]
Abstract
Complex networks of signaling pathways maintain the correct balance between positive and negative growth signals, ensuring that tissues achieve proper sizes and differentiation pattern during development. In Drosophila, Dpp, a member of the TGFβ family, plays two main roles during larval eye development. In the early eye primordium, Dpp promotes growth and cell survival, but later on, it switches its function to induce a developmentally-regulated cell cycle arrest in the G1 phase and neuronal photoreceptor differentiation. To advance in the identification and characterization of regulators and targets of Dpp signaling required for retinal development, we carried out an in vivo eye-targeted double-RNAi screen to identify punt (Type II TGFβ receptor) interactors. Using a set of 251 genes associated with eye development, we identified CtBP, Dad, Ago and Brk as punt genetic interactors. Here, we show that downregulation of Ago, or conditions causing increased tissue growth including overexpression of Myc or CyclinD-Cdk4 are sufficient to partially rescue punt-dependent growth and photoreceptor differentiation. Interestingly, we show a novel role for the transcriptional co-repressor CtBP in inhibiting Dpp-dependent Mad activation by phosphorylation, downstream or in parallel to Dad, the inhibitory Smad. Furthermore, CtBP downregulation activates JNK signaling pathway, implying a complex regulation of signaling pathways by CtBP during eye development.
Collapse
|
7
|
Spatial regulation of expanded transcription in the Drosophila wing imaginal disc. PLoS One 2018; 13:e0201317. [PMID: 30063727 PMCID: PMC6067730 DOI: 10.1371/journal.pone.0201317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/12/2018] [Indexed: 12/13/2022] Open
Abstract
Growth and patterning are coordinated during development to define organ size and shape. The growth, proliferation and differentiation of Drosophila wings are regulated by several conserved signaling pathways. Here, we show that the Salvador-Warts-Hippo (SWH) and Notch pathways converge on an enhancer in the expanded (ex) gene, which also responds to levels of the bHLH transcription factor Daughterless (Da). Separate cis-regulatory elements respond to Salvador-Warts-Hippo (SWH) and Notch pathways, to bHLH proteins, and to unidentified factors that repress ex transcription in the wing pouch and in the proneural region at the anterior wing margin. Senseless, a zinc-finger transcription factor acting in proneural regions, had a negative impact on ex transcription in the proneural region, but the transcriptional repressor Hairy had no effect. Our study suggests that a complex pattern of ex transcription results from integration of a uniform SWH signal with multiple other inputs, rather than from a pattern of SWH signaling.
Collapse
|
8
|
Ylla G, Piulachs MD, Belles X. Comparative Transcriptomics in Two Extreme Neopterans Reveals General Trends in the Evolution of Modern Insects. iScience 2018; 4:164-179. [PMID: 30240738 PMCID: PMC6147021 DOI: 10.1016/j.isci.2018.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/13/2018] [Accepted: 05/23/2018] [Indexed: 01/08/2023] Open
Abstract
The success of neopteran insects, with 1 million species described, is associated with developmental innovations such as holometaboly and the evolution from short to long germband embryogenesis. To unveil the mechanisms underlining these innovations, we compared gene expression during the ontogeny of two extreme neopterans, the cockroach Blattella germanica (polyneopteran, hemimetabolan, and short germband species) and the fly Drosophila melanogaster (endopterygote, holometabolan, and long germband species). Results revealed that genes associated with metamorphosis are predominantly expressed in late nymphal stages in B. germanica and in the early-mid embryo in D. melanogaster. In B. germanica the maternal to zygotic transition (MZT) concentrates early in embryogenesis, when juvenile hormone factors are significantly expressed. In D. melanogaster, the MZT extends throughout embryogenesis, during which time juvenile hormone factors appear to be unimportant. These differences possibly reflect broad trends in the evolution of development within neopterans, related to the germband type and the metamorphosis mode. Transcriptomes of cockroaches and flies show key differences along development Cockroaches and flies express metamorphosis factors with distinct timings in ontogeny Cockroaches methylate DNA in early embryogenesis, whereas flies do not MZT is limited to the early embryo in cockroaches, but it extends until hatching in flies
Collapse
Affiliation(s)
- Guillem Ylla
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003 Barcelona, Spain
| | - Maria-Dolors Piulachs
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003 Barcelona, Spain
| | - Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003 Barcelona, Spain.
| |
Collapse
|
9
|
Bhattacharya A, Li K, Quiquand M, Rimesso G, Baker NE. The Notch pathway regulates the Second Mitotic Wave cell cycle independently of bHLH proteins. Dev Biol 2017; 431:309-320. [PMID: 28919436 DOI: 10.1016/j.ydbio.2017.08.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/08/2017] [Accepted: 08/22/2017] [Indexed: 12/31/2022]
Abstract
Notch regulates both neurogenesis and cell cycle activity to coordinate precursor cell generation in the differentiating Drosophila eye. Mosaic analysis with mitotic clones mutant for Notch components was used to identify the pathway of Notch signaling that regulates the cell cycle in the Second Mitotic Wave. Although S phase entry depends on Notch signaling and on the transcription factor Su(H), the transcriptional co-activator Mam and the bHLH repressor genes of the E(spl)-Complex were not essential, although these are Su(H) coactivators and targets during the regulation of neurogenesis. The Second Mitotic Wave showed little dependence on ubiquitin ligases neuralized or mindbomb, and although the ligand Delta is required non-autonomously, partial cell cycle activity occurred in the absence of known Notch ligands. We found that myc was not essential for the Second Mitotic Wave. The Second Mitotic Wave did not require the HLH protein Extra macrochaetae, and the bHLH protein Daughterless was required only cell-nonautonomously. Similar cell cycle phenotypes for Daughterless and Atonal were consistent with requirement for neuronal differentiation to stimulate Delta expression, affecting Notch activity in the Second Mitotic Wave indirectly. Therefore Notch signaling acts to regulate the Second Mitotic Wave without activating bHLH gene targets.
Collapse
Affiliation(s)
- Abhishek Bhattacharya
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Ke Li
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Manon Quiquand
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Gerard Rimesso
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Nicholas E Baker
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
| |
Collapse
|
10
|
|