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Mönch TC, Smylla TK, Brändle F, Preiss A, Nagel AC. Novel Genome-Engineered H Alleles Differentially Affect Lateral Inhibition and Cell Dichotomy Processes during Bristle Organ Development. Genes (Basel) 2024; 15:552. [PMID: 38790181 PMCID: PMC11121709 DOI: 10.3390/genes15050552] [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: 03/26/2024] [Revised: 04/22/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024] Open
Abstract
Hairless (H) encodes the major antagonist in the Notch signaling pathway, which governs cellular differentiation of various tissues in Drosophila. By binding to the Notch signal transducer Suppressor of Hairless (Su(H)), H assembles repressor complexes onto Notch target genes. Using genome engineering, three new H alleles, HFA, HLLAA and HWA were generated and a phenotypic series was established by several parameters, reflecting the residual H-Su(H) binding capacity. Occasionally, homozygous HWA flies develop to adulthood. They were compared with the likewise semi-viable HNN allele affecting H-Su(H) nuclear entry. The H homozygotes were short-lived, sterile and flightless, yet showed largely normal expression of several mitochondrial genes. Typical for H mutants, both HWA and HNN homozygous alleles displayed strong defects in wing venation and mechano-sensory bristle development. Strikingly, however, HWA displayed only a loss of bristles, whereas bristle organs of HNN flies showed a complete shaft-to-socket transformation. Apparently, the impact of HWA is restricted to lateral inhibition, whereas that of HNN also affects the respective cell type specification. Notably, reduction in Su(H) gene dosage only suppressed the HNN bristle phenotype, but amplified that of HWA. We interpret these differences as to the role of H regarding Su(H) stability and availability.
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Affiliation(s)
- Tanja C. Mönch
- Department of Molecular Genetics, Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (T.C.M.); (T.K.S.); (F.B.)
| | - Thomas K. Smylla
- Department of Molecular Genetics, Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (T.C.M.); (T.K.S.); (F.B.)
| | - Franziska Brändle
- Department of Molecular Genetics, Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (T.C.M.); (T.K.S.); (F.B.)
| | - Anette Preiss
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany;
| | - Anja C. Nagel
- Department of Molecular Genetics, Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (T.C.M.); (T.K.S.); (F.B.)
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Clements R, Smith T, Cowart L, Zhumi J, Sherrod A, Cahill A, Hunter GL. Myosin XV is a negative regulator of signaling filopodia during long-range lateral inhibition. Dev Biol 2024; 505:110-121. [PMID: 37956923 PMCID: PMC10767839 DOI: 10.1016/j.ydbio.2023.11.002] [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: 08/17/2023] [Revised: 10/30/2023] [Accepted: 11/06/2023] [Indexed: 11/20/2023]
Abstract
The self-organization of cells during development is essential for the formation of healthy tissues and requires the coordination of cell activities at local scales. Cytonemes, or signaling filopodia, are dynamic actin-based cellular protrusions that allow cells to engage in contact mediated signaling at a distance. While signaling filopodia have been shown to support several signaling paradigms during development, less is understood about how these protrusions are regulated. We investigated the role of the plus-end directed, unconventional MyTH4-FERM myosins in regulating signaling filopodia during sensory bristle patterning on the dorsal thorax of the fruit fly Drosophila melanogaster. We found that Myosin XV is required for regulating signaling filopodia dynamics and, as a consequence, lateral inhibition more broadly throughout the patterning epithelium. We found that Myosin XV is required for limiting the length and number of signaling filopodia generated by bristle precursor cells. Cells with additional and longer signaling filopodia due to loss of Myosin XV are not signaling competent, due to altered levels of Delta ligand and Notch receptor along their lengths. We conclude that Myosin XV acts to negatively regulate signaling filopodia, as well as promote the ability of signaling filopodia to engage in long-range Notch signaling. Since Myosin XV isoforms are present across several vertebrate and invertebrate systems, this may have significance for other long-range signaling mechanisms.
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Affiliation(s)
- Rhiannon Clements
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States
| | - Tyler Smith
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States
| | - Luke Cowart
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States
| | - Jennifer Zhumi
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States
| | - Alan Sherrod
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States
| | - Aidan Cahill
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States
| | - Ginger L Hunter
- Department of Biology, Clarkson University, Potsdam, NY, 13699, United States.
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Troost T, Seib E, Airich A, Vüllings N, Necakov A, De Renzis S, Klein T. The meaning of ubiquitylation of the DSL ligand Delta for the development of Drosophila. BMC Biol 2023; 21:260. [PMID: 37974242 PMCID: PMC10655352 DOI: 10.1186/s12915-023-01759-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Ubiquitylation (ubi) of the intracellular domain of the Notch ligand Delta (Dl) by the E3 ligases Neuralized (Neur) and Mindbomb1 (Mib1) on lysines (Ks) is thought to be essential for the its signalling activity. Nevertheless, we have previously shown that DlK2R-HA, a Dl variant where all Ks in its intracellular domain (ICD) are replaced by the structurally similar arginine (R), still possess weak activity if over-expressed. This suggests that ubi is not absolutely required for Dl signalling. However, it is not known whether the residual activity of DlK2R-HA is an effect of over-expression and, if not, whether DlK2R can provide sufficient activity for the whole development of Drosophila. RESULTS To clarify these issues, we generated and analysed DlattP-DlK2R-HA, a knock-in allele into the Dl locus. Our analysis of this allele reveals that the sole presence of one copy of DlattP-DlK2R-HA can provide sufficient activity for completion of development. It further indicates that while ubi is required for the full activity of Dl in Mib1-dependent processes, it is not essential for Neur-controlled neural development. We identify three modes of Dl signalling that are either dependent or independent of ubi. Importantly, all modes depend on the presence of the endocytic adapter Epsin. During activation of Dl, direct binding of Epsin appears not to be an essential requirement. In addition, our analysis further reveals that the Ks are required to tune down the cis-inhibitory interaction of Dl with Notch. CONCLUSIONS Our results indicate that Dl can activate the Notch pathway without ubi of its ICD. It signals via three modes. Ubi is specifically required for the Mib1-dependent processes and the adjustment of cis-inhibition. In contrast to Mib1, Neur can efficiently activate Dl without ubi. Neur probably acts as an endocytic co-adapter in addition to its role as E3 ligase. Endocytosis, regulated in a ubi-dependent or ubi-independent manner is required for signalling and also suppression of cis-inhibition. The findings clarify the role of ubi of the ligands during Notch signalling.
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Affiliation(s)
- Tobias Troost
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Alina Airich
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Nicole Vüllings
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Aleksandar Necakov
- Department of Biological Science, Brock University, 1030, Ontario, L2S3A1, Canada
| | - Stefano De Renzis
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany.
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Presser A, Freund O, Hassapelis T, Hunter G. Scabrous is distributed via signaling filopodia to modulate Notch response during bristle patterning in Drosophila. PLoS One 2023; 18:e0291409. [PMID: 37729137 PMCID: PMC10511103 DOI: 10.1371/journal.pone.0291409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/29/2023] [Indexed: 09/22/2023] Open
Abstract
During development, cells in tissues must be patterned correctly in order to support tissue function and shape. The sensory bristles of the peripheral nervous system on the thorax of Drosophila melanogaster self-organizes from a unpatterned epithelial tissue to a regular spot pattern during pupal stages. Wild type patterning requires Notch-mediated lateral inhibition. Scabrous is a protein that can bind to and modify Notch receptor activity. Scabrous can be secreted, but it is also known to be localized to basal signaling filopodia, or cytonemes, that play a role in long-range Notch signaling. Here we show that Scabrous is primarily distributed basally, within the range of signaling filopodia extension. We show that filamentous actin dynamics are required for the distribution of Scabrous protein during sensory bristle patterning stages. We show that the Notch response of epithelial cells is sensitive to the level of Scabrous protein being expressed by the sensory bristle precursor cell. Our findings at the cell-level suggest a model for how epithelial cells engaged in lateral inhibition at a distance are sensitive local levels of Scabrous protein.
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Affiliation(s)
- Adam Presser
- Department of Biology, Clarkson University, Potsdam, New York, United States of America
| | - Olivia Freund
- Department of Biology, Clarkson University, Potsdam, New York, United States of America
| | - Theodora Hassapelis
- Department of Biology, Clarkson University, Potsdam, New York, United States of America
| | - Ginger Hunter
- Department of Biology, Clarkson University, Potsdam, New York, United States of America
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5
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Clements R, Smith T, Cowart L, Zhumi J, Sherrod A, Cahill A, Hunter GL. Myosin XV is a negative regulator of signaling filopodia during long-range lateral inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.547992. [PMID: 37461640 PMCID: PMC10350058 DOI: 10.1101/2023.07.07.547992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The self-organization of cells during development is essential for the formation of healthy tissues, and requires the coordination of cell activities at local scales. Cytonemes, or signaling filopodia, are dynamic actin-based cellular protrusions that allow cells to engage in contact mediated signaling at a distance. While signaling filopodia have been shown to support several signaling paradigms during development, less is understood about how these protrusions are regulated. We investigated the role of the plus-end directed, unconventional MyTH4-FERM myosins in regulating signaling filopodia during sensory bristle patterning on the dorsal thorax of the fruit fly Drosophila melanogaster. We found that Myosin XV is required for regulating signaling filopodia dynamics and, as a consequence, lateral inhibition more broadly throughout the patterning epithelium. We found that Myosin XV is required for limiting the length and number of signaling filopodia generated by bristle precursor cells. Cells with additional and longer signaling filopodia due to loss of Myosin XV are not signaling competent, due to altered levels of Delta ligand and Notch receptor along their lengths. We conclude that Myosin XV acts to negatively regulate signaling filopodia, as well as promote the ability of signaling filopodia to engage in long-range Notch signaling. Since Myosin XV is present across several vertebrate and invertebrate systems, this may have significance for other long-range signaling mechanisms.
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Affiliation(s)
| | - Tyler Smith
- Department of Biology, Clarkson University, Potsdam, NY, 13699, USA
| | - Luke Cowart
- Department of Biology, Clarkson University, Potsdam, NY, 13699, USA
| | - Jennifer Zhumi
- Department of Biology, Clarkson University, Potsdam, NY, 13699, USA
| | - Alan Sherrod
- Department of Biology, Clarkson University, Potsdam, NY, 13699, USA
| | - Aidan Cahill
- Department of Biology, Clarkson University, Potsdam, NY, 13699, USA
| | - Ginger L Hunter
- Department of Biology, Clarkson University, Potsdam, NY, 13699, USA
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6
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Troost T, Binshtok U, Sprinzak D, Klein T. Cis-inhibition suppresses basal Notch signaling during sensory organ precursor selection. Proc Natl Acad Sci U S A 2023; 120:e2214535120. [PMID: 37252950 PMCID: PMC10266033 DOI: 10.1073/pnas.2214535120] [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: 09/20/2022] [Accepted: 03/29/2023] [Indexed: 06/01/2023] Open
Abstract
The emergence of the sensory organ precursor (SOP) from an equivalence group in Drosophila is a paradigm for studying single-cell fate specification through Notch-mediated lateral inhibition. Yet, it remains unclear how only a single SOP is selected from a relatively large group of cells. We show here that a critical aspect of SOP selection is controlled by cis-inhibition (CI), whereby the Notch ligands, Delta (Dl), cis-inhibit Notch receptors in the same cell. Based on the observation that the mammalian ligand Dl-like 1 cannot cis-inhibit Notch in Drosophila, we probe the role of CI in vivo. We develop a mathematical model for SOP selection where Dl activity is independently regulated by the ubiquitin ligases Neuralized and Mindbomb1. We show theoretically and experimentally that Mindbomb1 induces basal Notch activity, which is suppressed by CI. Our results highlight the trade-off between basal Notch activity and CI as a mechanism for singling out a SOP from a large equivalence group.
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Affiliation(s)
- Tobias Troost
- Institut fuer Genetik, Heinrich-Heine-Universtitaet Duesseldorf40225Duesseldorf, Germany
| | - Udi Binshtok
- School of Neurobiology, Biochemistry, and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv69978, Israel
| | - David Sprinzak
- School of Neurobiology, Biochemistry, and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv69978, Israel
| | - Thomas Klein
- Institut fuer Genetik, Heinrich-Heine-Universtitaet Duesseldorf40225Duesseldorf, Germany
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7
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Abstract
Notch signaling is a highly conserved signaling pathway that coordinates cellular differentiation during the development and homeostasis in numerous organs and tissues across metazoans. Activation of Notch signaling relies on direct contact between neighboring cells and mechanical pulling of the Notch receptors by the Notch ligands. Notch signaling is commonly used in developmental processes to coordinate the differentiation into distinct cell fates of neighboring cells. In this Development at a Glance article, we describe the current understanding of the Notch pathway activation and the different regulatory levels that control the pathway. We then describe several developmental processes where Notch is crucial for coordinating differentiation. These examples include processes that are largely based on lateral inhibition mechanisms giving rise to alternating patterns (e.g. SOP selection, hair cell in the inner ear and neural stem cell maintenance), as well as processes where Notch activity is oscillatory (e.g. somitogenesis and neurogenesis in mammals).
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Affiliation(s)
- Oren Gozlan
- School of Neurobiology, Biochemistry, and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - David Sprinzak
- School of Neurobiology, Biochemistry, and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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8
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Maier D, Bauer M, Boger M, Sanchez Jimenez A, Yuan Z, Fechner J, Scharpf J, Kovall RA, Preiss A, Nagel AC. Genetic and Molecular Interactions between HΔCT, a Novel Allele of the Notch Antagonist Hairless, and the Histone Chaperone Asf1 in Drosophila melanogaster. Genes (Basel) 2023; 14:205. [PMID: 36672946 PMCID: PMC9858708 DOI: 10.3390/genes14010205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/03/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
Cellular differentiation relies on the highly conserved Notch signaling pathway. Notch activity induces gene expression changes that are highly sensitive to chromatin landscape. We address Notch gene regulation using Drosophila as a model, focusing on the genetic and molecular interactions between the Notch antagonist Hairless and the histone chaperone Asf1. Earlier work implied that Asf1 promotes the silencing of Notch target genes via Hairless (H). Here, we generate a novel HΔCT allele by genome engineering. Phenotypically, HΔCT behaves as a Hairless gain of function allele in several developmental contexts, indicating that the conserved CT domain of H has an attenuator role under native biological contexts. Using several independent methods to assay protein-protein interactions, we define the sequences of the CT domain that are involved in Hairless-Asf1 binding. Based on previous models, where Asf1 promotes Notch repression via Hairless, a loss of Asf1 binding should reduce Hairless repressive activity. However, tissue-specific Asf1 overexpression phenotypes are increased, not rescued, in the HΔCT background. Counterintuitively, Hairless protein binding mitigates the repressive activity of Asf1 in the context of eye development. These findings highlight the complex connections of Notch repressors and chromatin modulators during Notch target-gene regulation and open the avenue for further investigations.
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Affiliation(s)
- Dieter Maier
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
| | - Milena Bauer
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Mike Boger
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13–17, D-68167 Mannheim, Germany
| | - Anna Sanchez Jimenez
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
| | - Zhenyu Yuan
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Medical Sciences Building 2201, Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Johannes Fechner
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
- Institute of Biomedical Genetics (IBMG), University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany
| | - Janika Scharpf
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
| | - Rhett A. Kovall
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Medical Sciences Building 2201, Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Anette Preiss
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
| | - Anja C. Nagel
- Institute of Biology, Genetics Department 190g, University of Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
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Furman DP, Bukharina TA. Genetic Regulation of Morphogenesis of Drosophila melanogaster Mechanoreceptors. Russ J Dev Biol 2022. [DOI: 10.1134/s1062360422040038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Dean DM, Deitcher DL, Paster CO, Xu M, Loehlin DW. "A fly appeared": sable, a classic Drosophila mutation, maps to Yippee, a gene affecting body color, wings, and bristles. G3 (BETHESDA, MD.) 2022; 12:jkac058. [PMID: 35266526 PMCID: PMC9073688 DOI: 10.1093/g3journal/jkac058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/04/2022] [Indexed: 11/12/2022]
Abstract
Insect body color is an easily assessed and visually engaging trait that is informative on a broad range of topics including speciation, biomaterial science, and ecdysis. Mutants of the fruit fly Drosophila melanogaster have been an integral part of body color research for more than a century. As a result of this long tenure, backlogs of body color mutations have remained unmapped to their genes, all while their strains have been dutifully maintained, used for recombination mapping, and part of genetics education. Stemming from a lesson plan in our undergraduate genetics class, we have mapped sable1, a dark body mutation originally described by Morgan and Bridges, to Yippee, a gene encoding a predicted member of the E3 ubiquitin ligase complex. Deficiency/duplication mapping, genetic rescue, DNA and cDNA sequencing, RT-qPCR, and 2 new CRISPR alleles indicated that sable1 is a hypomorphic Yippee mutation due to an mdg4 element insertion in the Yippee 5'-UTR. Further analysis revealed additional Yippee mutant phenotypes including curved wings, ectopic/missing bristles, delayed development, and failed adult emergence. RNAi of Yippee in the ectoderm phenocopied sable body color and most other Yippee phenotypes. Although Yippee remains functionally uncharacterized, the results presented here suggest possible connections between melanin biosynthesis, copper homeostasis, and Notch/Delta signaling; in addition, they provide insight into past studies of sable cell nonautonomy and of the genetic modifier suppressor of sable.
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Affiliation(s)
- Derek M Dean
- Department of Biology, Williams College, Williamstown, MA 01267, USA
| | - David L Deitcher
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Caleigh O Paster
- Department of Biology, Williams College, Williamstown, MA 01267, USA
| | - Manting Xu
- Department of Biology, Williams College, Williamstown, MA 01267, USA
| | - David W Loehlin
- Department of Biology, Williams College, Williamstown, MA 01267, USA
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11
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Baeumers M, Ruhnau K, Breuer T, Pannen H, Goerlich B, Kniebel A, Haensch S, Weidtkamp-Peters S, Schmitt L, Klein T. Lethal (2) giant discs (Lgd)/CC2D1 is required for the full activity of the ESCRT machinery. BMC Biol 2020; 18:200. [PMID: 33349255 PMCID: PMC7754597 DOI: 10.1186/s12915-020-00933-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/24/2020] [Indexed: 01/10/2023] Open
Abstract
Background A major task of the endosomal sorting complex required for transport (ESCRT) machinery is the pinching off of cargo-loaded intraluminal vesicles (ILVs) into the lumen of maturing endosomes (MEs), which is essential for the complete degradation of transmembrane proteins in the lysosome. The ESCRT machinery is also required for the termination of signalling through activated signalling receptors, as it separates their intracellular domains from the cytosol. At the heart of the machinery lies the ESCRT-III complex, which is required for an increasing number of processes where membrane regions are abscised away from the cytosol. The core of ESCRT-III, comprising four members of the CHMP protein family, organises the assembly of a homopolymer of CHMP4, Shrub in Drosophila, that is essential for abscission. We and others identified the tumour-suppressor lethal (2) giant discs (Lgd)/CC2D1 as a physical interactor of Shrub/CHMP4 in Drosophila and mammals, respectively. Results Here, we show that the loss of function of lgd constitutes a state of reduced activity of Shrub/CHMP4/ESCRT-III. This hypomorphic shrub mutant situation causes a slight decrease in the rate of ILV formation that appears to result in incomplete incorporation of Notch into ILVs. We found that the forced incorporation in ILVs of lgd mutant MEs suppresses the uncontrolled and ligand-independent activation of Notch. Moreover, the analysis of Su(dx) lgd double mutants clarifies their relationship and suggests that they are not operating in a linear pathway. We could show that, despite prolonged lifetime, the MEs of lgd mutants have a similar ILV density as wild-type but less than rab7 mutant MEs, suggesting the rate in lgd mutants is slightly reduced. The analysis of the MEs of wild-type and mutant cells in the electron microscope revealed that the ESCRT-containing electron-dense microdomains of ILV formation at the limiting membrane are elongated, indicating a change in ESCRT activity. Since lgd mutants can be rescued to normal adult flies if extra copies of shrub (or its mammalian ortholog CHMP4B) are added into the genome, we conclude that the net activity of Shrub is reduced upon loss of lgd function. Finally, we show that, in solution, CHMP4B/Shrub exists in two conformations. LGD1/Lgd binding does not affect the conformational state of Shrub, suggesting that Lgd is not a chaperone for Shrub/CHMP4B. Conclusion Our results suggest that Lgd is required for the full activity of Shrub/ESCRT-III. In its absence, the activity of the ESCRT machinery is reduced. This reduction causes the escape of a fraction of cargo, among it Notch, from incorporation into ILVs, which in turn leads to an activation of this fraction of Notch after fusion of the ME with the lysosome. Our results highlight the importance of the incorporation of Notch into ILV not only to assure complete degradation, but also to avoid uncontrolled activation of the pathway.
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Affiliation(s)
- Miriam Baeumers
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Kristina Ruhnau
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Thomas Breuer
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Hendrik Pannen
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Bastian Goerlich
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Anna Kniebel
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Sebastian Haensch
- Center of Advanced Imaging (CAi), Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Stefanie Weidtkamp-Peters
- Center of Advanced Imaging (CAi), Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry I, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany.
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Giri R, Papadopoulos DK, Posadas DM, Potluri HK, Tomancak P, Mani M, Carthew RW. Ordered patterning of the sensory system is susceptible to stochastic features of gene expression. eLife 2020; 9:e53638. [PMID: 32101167 PMCID: PMC7064346 DOI: 10.7554/elife.53638] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/25/2020] [Indexed: 01/23/2023] Open
Abstract
Sensory neuron numbers and positions are precisely organized to accurately map environmental signals in the brain. This precision emerges from biochemical processes within and between cells that are inherently stochastic. We investigated impact of stochastic gene expression on pattern formation, focusing on senseless (sens), a key determinant of sensory fate in Drosophila. Perturbing microRNA regulation or genomic location of sens produced distinct noise signatures. Noise was greatly enhanced when both sens alleles were present in homologous loci such that each allele was regulated in trans by the other allele. This led to disordered patterning. In contrast, loss of microRNA repression of sens increased protein abundance but not sensory pattern disorder. This suggests that gene expression stochasticity is a critical feature that must be constrained during development to allow rapid yet accurate cell fate resolution.
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Affiliation(s)
- Ritika Giri
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
- NSF-Simons Center for Quantitative Biology, Northwestern UniversityEvanstonUnited States
| | | | - Diana M Posadas
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Hemanth K Potluri
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Pavel Tomancak
- Max Planck Institute of Cell Biology and GeneticsDresdenGermany
| | - Madhav Mani
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
- NSF-Simons Center for Quantitative Biology, Northwestern UniversityEvanstonUnited States
- Department of Engineering Sciences and Applied Mathematics, Northwestern UniversityEvanstonUnited States
| | - Richard W Carthew
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
- NSF-Simons Center for Quantitative Biology, Northwestern UniversityEvanstonUnited States
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13
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Schweisguth F, Corson F. Self-Organization in Pattern Formation. Dev Cell 2020; 49:659-677. [PMID: 31163171 DOI: 10.1016/j.devcel.2019.05.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 02/16/2019] [Accepted: 05/07/2019] [Indexed: 12/19/2022]
Abstract
Self-organization is pervasive in development, from symmetry breaking in the early embryo to tissue patterning and morphogenesis. For a few model systems, the underlying molecular and cellular processes are now sufficiently characterized that mathematical models can be confronted with experiments, to explore the dynamics of pattern formation. Here, we review selected systems, ranging from cyanobacteria to mammals, where different forms of cell-cell communication, acting alone or together with positional cues, drive the patterning of cell fates, highlighting the insights that even very simple models can provide as well as the challenges on the path to a predictive understanding of development.
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Affiliation(s)
- François Schweisguth
- Institut Pasteur, Department of Developmental and Stem Cell Biology F-75015 Paris, France; CNRS, UMR 3738 F-75015 Paris, France.
| | - Francis Corson
- Laboratoire de Physique de l'Ecole Normale Supérieure, CNRS, Sorbonne Université, Université Paris Diderot 75005 Paris, France.
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14
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Notch Signalling: The Multitask Manager of Inner Ear Development and Regeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1218:129-157. [DOI: 10.1007/978-3-030-34436-8_8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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15
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Crews ST. Drosophila Embryonic CNS Development: Neurogenesis, Gliogenesis, Cell Fate, and Differentiation. Genetics 2019; 213:1111-1144. [PMID: 31796551 PMCID: PMC6893389 DOI: 10.1534/genetics.119.300974] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/26/2019] [Indexed: 01/04/2023] Open
Abstract
The Drosophila embryonic central nervous system (CNS) is a complex organ consisting of ∼15,000 neurons and glia that is generated in ∼1 day of development. For the past 40 years, Drosophila developmental neuroscientists have described each step of CNS development in precise molecular genetic detail. This has led to an understanding of how an intricate nervous system emerges from a single cell. These studies have also provided important, new concepts in developmental biology, and provided an essential model for understanding similar processes in other organisms. In this article, the key genes that guide Drosophila CNS development and how they function is reviewed. Features of CNS development covered in this review are neurogenesis, gliogenesis, cell fate specification, and differentiation.
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Affiliation(s)
- Stephen T Crews
- Department of Biochemistry and Biophysics, Integrative Program for Biological and Genome Sciences, School of Medicine, The University of North Carolina at Chapel Hill, North Carolina 27599
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16
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Couturier L, Mazouni K, Corson F, Schweisguth F. Regulation of Notch output dynamics via specific E(spl)-HLH factors during bristle patterning in Drosophila. Nat Commun 2019; 10:3486. [PMID: 31375669 PMCID: PMC6677740 DOI: 10.1038/s41467-019-11477-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 07/03/2019] [Indexed: 12/13/2022] Open
Abstract
The stereotyped arrangement of sensory bristles on the adult fly thorax arises from a self-organized process, in which inhibitory Notch signaling both delimits proneural stripes and singles out sensory organ precursor cells (SOPs). A dynamic balance between proneural factors and Enhancer of split-HLH (E(spl)-HLH) Notch targets underlies patterning, but how this is regulated is unclear. Here, were identify two classes of E(spl)-HLH factors, whose expression both precedes and delimits proneural activity, and is dependent on proneural activity and required for proper SOP spacing within the stripes, respectively. These two classes are partially redundant, since a member of the second class, that is normally cross-repressed by members of the first class, can functionally compensate for their absence. The regulation of specific E(spl)-HLH genes by proneural factors amplifies the response to Notch as SOPs are being selected, contributing to patterning dynamics in the notum, and likely operates in other developmental contexts. The patterning of sensory bristles on the dorsal thorax of flies is regulated by two transcription factor families but the dynamics of this regulation is unclear. Here, the authors visualize seven E(spl)-HLH proteins, showing their regulated expression promotes mutual inhibition by Notch during notum patterning.
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Affiliation(s)
- Lydie Couturier
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015, Paris, France.,CNRS, UMR3738, 75015, Paris, France
| | - Khalil Mazouni
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015, Paris, France.,CNRS, UMR3738, 75015, Paris, France
| | - Francis Corson
- Laboratoire de Physique de l'Ecole Normale Supérieure, CNRS, Sorbonne Université, Université Paris Diderot, 75005, Paris, France
| | - François Schweisguth
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015, Paris, France. .,CNRS, UMR3738, 75015, Paris, France.
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17
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Li K, Baker NE. Transcriptional and post-transcriptional regulation of extra macrochaetae during Drosophila adult peripheral neurogenesis. Dev Biol 2019; 449:41-51. [PMID: 30771303 DOI: 10.1016/j.ydbio.2019.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/11/2019] [Accepted: 02/11/2019] [Indexed: 11/18/2022]
Abstract
Regulation of the Drosophila ID protein Extra macrochaetae (Emc) is important because reduced Emc levels have been proposed to favor proneural gene activity and thereby define a prepattern for neurogenesis. Recent studies suggest a major role for post-translational control of Emc levels. To further define the mechanisms of Emc regulation, we identified two redundant cis-regulatory regions by germline transformation-rescue experiments that make use of new molecularly-defined emc mutants. We distinguished the mechanisms by which Daughterless (Da) regulated Emc expression, finding post-translational regulation in most tissues, and additional transcriptional regulation in the eye imaginal disc posterior to the morphogenetic furrow. Dpp and Hh signaling pathways repressed Emc transcriptionally and post-translationally within the morphogenetic furrow of the eye disc, whereas Wg signaling repressed Emc expression at the anterior margin of the wing imaginal disc. Although the emc 3' UTR is potentially regulatory, no effect of miRNA pathways on Emc protein levels was discernible. Our work supports recent evidence that post-transcriptional mechanisms contribute more to regulation of Emc protein levels than transcriptional mechanisms do.
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Affiliation(s)
- Ke Li
- 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.
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18
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Hunter GL, He L, Perrimon N, Charras G, Giniger E, Baum B. A role for actomyosin contractility in Notch signaling. BMC Biol 2019; 17:12. [PMID: 30744634 PMCID: PMC6369551 DOI: 10.1186/s12915-019-0625-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/04/2019] [Indexed: 12/24/2022] Open
Abstract
Background Notch-Delta signaling functions across a wide array of animal systems to break symmetry in a sheet of undifferentiated cells and generate cells with different fates, a process known as lateral inhibition. Unlike many other signaling systems, however, since both the ligand and receptor are transmembrane proteins, the activation of Notch by Delta depends strictly on cell-cell contact. Furthermore, the binding of the ligand to the receptor may not be sufficient to induce signaling, since recent work in cell culture suggests that ligand-induced Notch signaling also requires a mechanical pulling force. This tension exposes a cleavage site in Notch that, when cut, activates signaling. Although it is not known if mechanical tension contributes to signaling in vivo, others have suggested that this is how endocytosis of the receptor-ligand complex contributes to the cleavage and activation of Notch. In a similar way, since Notch-mediated lateral inhibition at a distance in the dorsal thorax of the pupal fly is mediated via actin-rich protrusions, it is possible that cytoskeletal forces generated by networks of filamentous actin and non-muscle myosin during cycles of protrusion extension and retraction also contribute to Notch signaling. Results To test this hypothesis, we carried out a detailed analysis of the role of myosin II-dependent tension in Notch signaling in the developing fly and in cell culture. Using dynamic fluorescence-based reporters of Notch, we found that myosin II is important for signaling in signal sending and receiving cells in both systems—as expected if myosin II-dependent tension across the Notch-Delta complex contributes to Notch activation. While myosin II was found to contribute most to signaling at a distance, it was also required for maximal signaling between adjacent cells that share lateral contacts and for signaling between cells in culture. Conclusions Together these results reveal a previously unappreciated role for non-muscle myosin II contractility in Notch signaling, providing further support for the idea that force contributes to the cleavage and activation of Notch in the context of ligand-dependent signaling, and a new paradigm for actomyosin-based mechanosensation. Electronic supplementary material The online version of this article (10.1186/s12915-019-0625-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ginger L Hunter
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA. .,MRC-LMCB, University College London, London, WC1E6BT, UK. .,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK. .,Present Address: Department of Biology, Clarkson University, Potsdam, NY, 13699, USA.
| | - Li He
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London, WC1E6BT, UK.,Department of Cell and Developmental Biology, University College London, London, WC1E6BT, UK
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA.
| | - Buzz Baum
- MRC-LMCB, University College London, London, WC1E6BT, UK.,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK
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19
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Furman DP, Bukharina TV. The bristle pattern development in Drosophila melanogaster: the prepattern and achaete-scute genes. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj18.449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- D. P. Furman
- Institute of Cytology and Genetics, SB RAS; Novosibirsk State University
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20
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Miller SW, Posakony JW. Lateral inhibition: Two modes of non-autonomous negative autoregulation by neuralized. PLoS Genet 2018; 14:e1007528. [PMID: 30028887 PMCID: PMC6070291 DOI: 10.1371/journal.pgen.1007528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 08/01/2018] [Accepted: 07/01/2018] [Indexed: 11/18/2022] Open
Abstract
Developmental patterning involves the progressive subdivision of tissue into different cell types by invoking different genetic programs. In particular, cell-cell signaling is a universally deployed means of specifying distinct cell fates in adjacent cells. For this mechanism to be effective, it is essential that an asymmetry be established in the signaling and responding capacities of the participating cells. Here we focus on the regulatory mechanisms underlying the role of the neuralized gene and its protein product in establishing and maintaining asymmetry of signaling through the Notch pathway. The context is the classical process of “lateral inhibition” within Drosophila proneural clusters, which is responsible for distinguishing the sensory organ precursor (SOP) and non-SOP fates among adjacent cells. We find that neur is directly regulated in proneural clusters by both proneural transcriptional activators and Enhancer of split basic helix-loop-helix repressors (bHLH-Rs), via two separate cis-regulatory modules within the neur locus. We show that this bHLH-R regulation is required to prevent the early, pre-SOP expression of neur from being maintained in a subset of non-SOPs following SOP specification. Lastly, we demonstrate that Neur activity in the SOP is required to inhibit, in a cell non-autonomous manner, both neur expression and Neur function in non-SOPs, thus helping to secure the robust establishment of distinct cell identities within the developing proneural cluster. Much of the process of animal development is concerned with giving cells specific instructions as to what type of cell they are to become—their “fate”. Often, it is even necessary to assign very different fates to cells that are adjacent to each other in the tissue. In such cases, cell-to-cell signaling is frequently utilized as the means of distinguishing the cells’ fates. For example, one cell might send a signal to its neighbors that inhibits them from adopting the same fate as itself. Here, it is obviously vital that there is an asymmetry between the “sending” and “receiving” cells in the ability to transmit such a signal. In the fruit fly Drosophila, the gene neuralized encodes a protein that plays a critical role in establishing the capacity to send such an inhibitory signal. The work we describe here reveals specifically how the receiving cells are prevented from acquiring the ability to send the signal. Remarkably, the Neuralized protein itself is deeply involved in this process. Neuralized function in the sending cell generates two distinct mechanisms that inhibit its own activity in the receiving cells.
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Affiliation(s)
- Steven W. Miller
- Division of Biological Sciences, Section of Cell & Developmental Biology, University of California San Diego, La Jolla, California, United States of America
| | - James W. Posakony
- Division of Biological Sciences, Section of Cell & Developmental Biology, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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21
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Li K, Baker NE. Regulation of the Drosophila ID protein Extra macrochaetae by proneural dimerization partners. eLife 2018; 7:33967. [PMID: 29687780 PMCID: PMC5915177 DOI: 10.7554/elife.33967] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/25/2018] [Indexed: 12/13/2022] Open
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 dimers could be a feature of bHLH-mediated developmental events.
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Affiliation(s)
- Ke Li
- Department of Genetics, Albert Einstein College of Medicine, Bronx, United States
| | - Nicholas E Baker
- Department of Genetics, Albert Einstein College of Medicine, Bronx, United States.,Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, United States.,Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, United States
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22
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Salazar JL, Yamamoto S. Integration of Drosophila and Human Genetics to Understand Notch Signaling Related Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1066:141-185. [PMID: 30030826 PMCID: PMC6233323 DOI: 10.1007/978-3-319-89512-3_8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Notch signaling research dates back to more than one hundred years, beginning with the identification of the Notch mutant in the fruit fly Drosophila melanogaster. Since then, research on Notch and related genes in flies has laid the foundation of what we now know as the Notch signaling pathway. In the 1990s, basic biological and biochemical studies of Notch signaling components in mammalian systems, as well as identification of rare mutations in Notch signaling pathway genes in human patients with rare Mendelian diseases or cancer, increased the significance of this pathway in human biology and medicine. In the 21st century, Drosophila and other genetic model organisms continue to play a leading role in understanding basic Notch biology. Furthermore, these model organisms can be used in a translational manner to study underlying mechanisms of Notch-related human diseases and to investigate the function of novel disease associated genes and variants. In this chapter, we first briefly review the major contributions of Drosophila to Notch signaling research, discussing the similarities and differences between the fly and human pathways. Next, we introduce several biological contexts in Drosophila in which Notch signaling has been extensively characterized. Finally, we discuss a number of genetic diseases caused by mutations in genes in the Notch signaling pathway in humans and we expand on how Drosophila can be used to study rare genetic variants associated with these and novel disorders. By combining modern genomics and state-of-the art technologies, Drosophila research is continuing to reveal exciting biology that sheds light onto mechanisms of disease.
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Affiliation(s)
- Jose L Salazar
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA.
- Program in Developmental Biology, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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23
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Sjöqvist M, Andersson ER. Do as I say, Not(ch) as I do: Lateral control of cell fate. Dev Biol 2017; 447:58-70. [PMID: 28969930 DOI: 10.1016/j.ydbio.2017.09.032] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/15/2017] [Accepted: 09/26/2017] [Indexed: 01/19/2023]
Abstract
Breaking symmetry in populations of uniform cells, to induce adoption of an alternative cell fate, is an essential developmental mechanism. Similarly, domain and boundary establishment are crucial steps to forming organs during development. Notch signaling is a pathway ideally suited to mediating precise patterning cues, as both receptors and ligands are membrane-bound and can thus act as a precise switch to toggle cell fates on or off. Fine-tuning of signaling by positive or negative feedback mechanisms dictate whether signaling results in lateral induction or lateral inhibition, respectively, allowing Notch to either induce entire regions of cell specification, or dictate binary fate choices. Furthermore, pathway activity is modulated by Fringe modification of receptors or ligands, co-expression of receptors with ligands, mode of ligand presentation, and cell surface area in contact. In this review, we describe how Notch signaling is fine-tuned to mediate lateral induction or lateral inhibition cues, and discuss examples from C.elegans, D. melanogaster and M. musculus. Identifying the cellular machinery dictating the choice between lateral induction and lateral inhibition highlights the versatility of the Notch signaling pathway in development.
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Affiliation(s)
- Marika Sjöqvist
- Department of Biosciences and Nutrition, Karolinska Institutet, Sweden
| | - Emma R Andersson
- Department of Biosciences and Nutrition, Karolinska Institutet, Sweden.
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24
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Berndt N, Seib E, Kim S, Troost T, Lyga M, Langenbach J, Haensch S, Kalodimou K, Delidakis C, Klein T. Ubiquitylation-independent activation of Notch signalling by Delta. eLife 2017; 6:27346. [PMID: 28960177 PMCID: PMC5675594 DOI: 10.7554/elife.27346] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/28/2017] [Indexed: 12/29/2022] Open
Abstract
Ubiquitylation (ubi) by the E3-ligases Mindbomb1 (Mib1) and Neuralized (Neur) is required for activation of the DSL ligands Delta (Dl) and Serrate (Ser) to activate Notch signalling. These ligases transfer ubiquitin to lysines of the ligands' intracellular domains (ICDs), which sends them into an Epsin-dependent endocytic pathway. Here, we have tested the requirement of ubi of Dl for signalling. We found that Dl requires ubi for its full function, but can also signal in two ubi-independent modes, one dependent and one independent of Neur. We identified two neural lateral specification processes where Dl signals in an ubi-independent manner. Neur, which is needed for these processes, was shown to be able to activate Dl in an ubi-independent manner. Our analysis suggests that one important role of DSL protein ubi by Mib1 is their release from cis-inhibitory interactions with Notch, enabling them to trans-activate Notch on adjacent cells.
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Affiliation(s)
- Nicole Berndt
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Soya Kim
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany.,Molekulare Zellbiologie, Institut I für Anatomie, Uniklinik Köln, Universität zu Köln, Köln, Germany
| | - Tobias Troost
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Marvin Lyga
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Jessica Langenbach
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Sebastian Haensch
- Center of Advanced Imaging, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Konstantina Kalodimou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Christos Delidakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
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25
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The Canonical Notch Signaling Pathway: Structural and Biochemical Insights into Shape, Sugar, and Force. Dev Cell 2017; 41:228-241. [PMID: 28486129 DOI: 10.1016/j.devcel.2017.04.001] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/04/2017] [Accepted: 04/03/2017] [Indexed: 02/07/2023]
Abstract
The Notch signaling pathway relies on a proteolytic cascade to release its transcriptionally active intracellular domain, on force to unfold a protective domain and permit proteolysis, on extracellular domain glycosylation to tune the forces exerted by endocytosed ligands, and on a motley crew of nuclear proteins, chromatin modifiers, ubiquitin ligases, and a few kinases to regulate activity and half-life. Herein we provide a review of recent molecular insights into how Notch signals are triggered and how cell shape affects these events, and we use the new insights to illuminate a few perplexing observations.
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26
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Meserve JH, Duronio RJ. A population of G2-arrested cells are selected as sensory organ precursors for the interommatidial bristles of the Drosophila eye. Dev Biol 2017. [PMID: 28645749 DOI: 10.1016/j.ydbio.2017.06.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cell cycle progression and differentiation are highly coordinated during the development of multicellular organisms. The mechanisms by which these processes are coordinated and how their coordination contributes to normal development are not fully understood. Here, we determine the developmental fate of a population of precursor cells in the developing Drosophila melanogaster retina that arrest in G2 phase of the cell cycle and investigate whether cell cycle phase-specific arrest influences the fate of these cells. We demonstrate that retinal precursor cells that arrest in G2 during larval development are selected as sensory organ precursors (SOPs) during pupal development and undergo two cell divisions to generate the four-cell interommatidial mechanosensory bristles. While G2 arrest is not required for bristle development, preventing G2 arrest results in incorrect bristle positioning in the adult eye. We conclude that G2-arrested cells provide a positional cue during development to ensure proper spacing of bristles in the eye. Our results suggest that the control of cell cycle progression refines cell fate decisions and that the relationship between these two processes is not necessarily deterministic.
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Affiliation(s)
- Joy H Meserve
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robert J Duronio
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA; Departments of Biology and Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA.
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27
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Caspase-dependent non-apoptotic processes in development. Cell Death Differ 2017; 24:1422-1430. [PMID: 28524858 PMCID: PMC5520453 DOI: 10.1038/cdd.2017.36] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 12/16/2022] Open
Abstract
Caspases are at the core of executing apoptosis by orchestrating cellular destruction with proteolytic cascades. Caspase-mediated proteolysis also controls diverse nonlethal cellular activities such as proliferation, differentiation, cell fate decision, and cytoskeletal reorganization. During the last decade or so, genetic studies of Drosophila have contributed to our understanding of the in vivo mechanism of the non-apoptotic cellular responses in developmental contexts. Furthermore, recent studies using C. elegans suggest that apoptotic signaling may play unexpected roles, which influence ageing and normal development at the organism level. In this review, we describe how the caspase activity is elaborately controlled during vital cellular processes at the level of subcellular localization, the duration and timing to avoid full apoptotic consequences, and also discuss the novel roles of non-apoptotic caspase signaling in adult homeostasis and physiology.
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Corson F, Couturier L, Rouault H, Mazouni K, Schweisguth F. Self-organized Notch dynamics generate stereotyped sensory organ patterns in Drosophila. Science 2017; 356:science.aai7407. [PMID: 28386027 DOI: 10.1126/science.aai7407] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 03/20/2017] [Indexed: 12/26/2022]
Abstract
The emergence of spatial patterns in developing multicellular organisms relies on positional cues and cell-cell communication. Drosophila sensory organs have informed a paradigm in which these operate in two distinct steps: Prepattern factors drive localized proneural activity, then Notch-mediated lateral inhibition singles out neural precursors. Here we show that self-organization through Notch signaling also establishes the proneural stripes that resolve into rows of sensory bristles on the fly thorax. Patterning, initiated by a gradient of Delta ligand expression, progresses through inhibitory signaling between and within stripes. Thus, Notch signaling can support self-organized tissue patterning as a prepattern is transduced by cell-cell interactions into a refined arrangement of cellular fates.
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Affiliation(s)
- Francis Corson
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, CNRS, Université Pierre et Marie Curie, Université Paris Diderot, 75005 Paris, France.
| | - Lydie Couturier
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France.,CNRS, UMR3738, 75015 Paris, France
| | - Hervé Rouault
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France.,CNRS, UMR3738, 75015 Paris, France
| | - Khalil Mazouni
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France.,CNRS, UMR3738, 75015 Paris, France
| | - François Schweisguth
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France. .,CNRS, UMR3738, 75015 Paris, France
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Abdolazimi Y, Stojanova Z, Segil N. Selection of cell fate in the organ of Corti involves the integration of Hes/Hey signaling at the Atoh1 promoter. Development 2016; 143:841-50. [PMID: 26932672 DOI: 10.1242/dev.129320] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Determination of cell fate within the prosensory domain of the developing cochlear duct relies on the temporal and spatial regulation of the bHLH transcription factor Atoh1. Auditory hair cells and supporting cells arise in a wave of differentiation that patterns them into discrete rows mediated by Notch-dependent lateral inhibition. However, the mechanism responsible for selecting sensory cells from within the prosensory competence domain remains poorly understood. We show in mice that rather than being upregulated in rows of cells, Atoh1 is subject to transcriptional activation in groups of prosensory cells, and that highly conserved sites for Hes/Hey repressor binding in the Atoh1 promoter are needed to select the hair cell and supporting cell fate. During perinatal supporting cell transdifferentiation, which is a model of hair cell regeneration, we show that derepression is sufficient to induce Atoh1 expression, suggesting a mechanism for priming the 3' Atoh1 autoregulatory enhancer needed for hair cell expression.
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Affiliation(s)
- Yassan Abdolazimi
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at USC, 1425 San Pablo St., Los Angeles, CA 90033, USA GMCB Graduate Program, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at USC, 1425 San Pablo St., Los Angeles, CA 90033, USA
| | - Zlatka Stojanova
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at USC, 1425 San Pablo St., Los Angeles, CA 90033, USA
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Biology at USC, 1425 San Pablo St., Los Angeles, CA 90033, USA Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine of the University of Southern California, 1450 San Pablo St., Suite 5100, Los Angeles, CA 90033, USA
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Shinoda N, Obata F, Zhang L, Miura M. Drosophila SETDB1 and caspase cooperatively fine-tune cell fate determination of sensory organ precursor. Genes Cells 2016; 21:378-86. [PMID: 26914287 DOI: 10.1111/gtc.12348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/06/2016] [Indexed: 12/18/2022]
Abstract
Drosophila produce a constant number of mechanosensory bristles called macrochaetae (MC), which develop from sensory organ precursor (SOP) cells within a proneural cluster (PNC). However, what ensures the precise determination of SOP cells remains to be elucidated. In this study, we conducted RNAi screening in PNC for genes involved in epigenetic regulation. We identified a H3K9 histone methyltransferase, SETDB1/eggless, as a regulator of SOP development. Knockdown of SETDB1 in PNC led to additional SOPs. We further tested the relationship between SETDB1 and non-apoptotic function of caspase on SOP development. Reinforcing caspase activation by heterozygous Drosophila inhibitor of apoptosis protein 1 (DIAP1) mutation rescued ectopic SOP development caused by SETDB1 knockdown. Knockdown of SETDB1, however, had little effect on caspase activity. Simultaneous loss of SETDB1 and caspase activity resulted in further increase in MC, indicating that the two components work cooperatively. Our study suggests the fine-tuning mechanisms for SOP development by epigenetic methyltransferase and non-apoptotic caspase function.
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Affiliation(s)
- Natsuki Shinoda
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Fumiaki Obata
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Liu Zhang
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Agency for Medical Research and Development-Core Research for Evolutional Medical Science and Technology (AMED-CREST), Japan Agency for Medical Research and Development, 20F Yomiuri Shimbun Building 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
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Tamberg L, Sepp M, Timmusk T, Palgi M. Introducing Pitt-Hopkins syndrome-associated mutations of TCF4 to Drosophila daughterless. Biol Open 2015; 4:1762-71. [PMID: 26621827 PMCID: PMC4736037 DOI: 10.1242/bio.014696] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pitt-Hopkins syndrome (PTHS) is caused by haploinsufficiency of Transcription factor 4 (TCF4), one of the three human class I basic helix-loop-helix transcription factors called E-proteins. Drosophila has a single E-protein, Daughterless (Da), homologous to all three mammalian counterparts. Here we show that human TCF4 can rescue Da deficiency during fruit fly nervous system development. Overexpression of Da or TCF4 specifically in adult flies significantly decreases their survival rates, indicating that these factors are crucial even after development has been completed. We generated da transgenic fruit fly strains with corresponding missense mutations R578H, R580W, R582P and A614V found in TCF4 of PTHS patients and studied the impact of these mutations in vivo. Overexpression of wild type Da as well as human TCF4 in progenitor tissues induced ectopic sensory bristles and the rough eye phenotype. By contrast, overexpression of DaR580W and DaR582P that disrupt DNA binding reduced the number of bristles and induced the rough eye phenotype with partial lack of pigmentation, indicating that these act dominant negatively. Compared to the wild type, DaR578H and DaA614V were less potent in induction of ectopic bristles and the rough eye phenotype, respectively, suggesting that these are hypomorphic. All studied PTHS-associated mutations that we introduced into Da led to similar effects in vivo as the same mutations in TCF4 in vitro. Consequently, our Drosophila models of PTHS are applicable for further studies aiming to unravel the molecular mechanisms of this disorder. Summary: Introducing mutations of the TCF4 gene found in human patients into its fly orthologue daughterless allows the generation of Drosophila models for research into Pitt-Hopkins syndrome.
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Affiliation(s)
- Laura Tamberg
- Laboratory of Molecular Neurobiology, Department of Gene Technology, Tallinn University of Technology, Akadeemia Rd.15, Tallinn 12618, Estonia
| | - Mari Sepp
- Laboratory of Molecular Neurobiology, Department of Gene Technology, Tallinn University of Technology, Akadeemia Rd.15, Tallinn 12618, Estonia
| | - Tõnis Timmusk
- Laboratory of Molecular Neurobiology, Department of Gene Technology, Tallinn University of Technology, Akadeemia Rd.15, Tallinn 12618, Estonia
| | - Mari Palgi
- Laboratory of Molecular Neurobiology, Department of Gene Technology, Tallinn University of Technology, Akadeemia Rd.15, Tallinn 12618, Estonia
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