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Baccas M, Ganesan V, Leung A, Pineiro L, McKillop AN, Liu J. SEM-2/SoxC regulates multiple aspects of C. elegans postembryonic mesoderm development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.04.602042. [PMID: 39005444 PMCID: PMC11245110 DOI: 10.1101/2024.07.04.602042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Development of multicellular organisms requires well-orchestrated interplay between cell-intrinsic transcription factors and cell-cell signaling. One set of highly conserved transcription factors that plays diverse roles in development is the SoxC group. C. elegans contains a sole SoxC protein, SEM-2. SEM-2 is essential for embryonic development, and for specifying the sex myoblast (SM) fate in the postembryonic mesoderm, the M lineage. We have identified a novel partial loss-of-function sem-2 allele that has a proline to serine change in the C-terminal tail of the highly conserved DNA-binding domain. Detailed analyses of mutant animals harboring this point mutation uncovered new functions of SEM-2 in the M lineage. First, SEM-2 functions antagonistically with LET-381, the sole C. elegans FoxF/C forkhead transcription factor, to regulate dorsoventral patterning of the M lineage. Second, in addition to specifying the SM fate, SEM-2 is essential for the proliferation and diversification of the SM lineage. Finally, SEM-2 appears to directly regulate the expression of hlh-8, which encodes a basic helix-loop-helix Twist transcription factor and plays critical roles in proper patterning of the M lineage. Our data, along with previous studies, suggest an evolutionarily conserved relationship between SoxC and Twist proteins. Furthermore, our work identified new interactions in the gene regulatory network (GRN) underlying C. elegans postembryonic development and adds to the general understanding of the structure-function relationship of SoxC proteins.
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Affiliation(s)
- Marissa Baccas
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Vanathi Ganesan
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Amy Leung
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Lucas Pineiro
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | | | - Jun Liu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
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2
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Stefanakis N, Jiang J, Liang Y, Shaham S. LET-381/FoxF and its target UNC-30/Pitx2 specify and maintain the molecular identity of C. elegans mesodermal glia that regulate motor behavior. EMBO J 2024; 43:956-992. [PMID: 38360995 PMCID: PMC10943081 DOI: 10.1038/s44318-024-00049-w] [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: 09/07/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/17/2024] Open
Abstract
While most glial cell types in the central nervous system (CNS) arise from neuroectodermal progenitors, some, like microglia, are mesodermally derived. To understand mesodermal glia development and function, we investigated C. elegans GLR glia, which envelop the brain neuropil and separate it from the circulatory system cavity. Transcriptome analysis shows that GLR glia combine astrocytic and endothelial characteristics, which are relegated to separate cell types in vertebrates. Combined fate acquisition is orchestrated by LET-381/FoxF, a fate-specification/maintenance transcription factor also expressed in glia and endothelia of other animals. Among LET-381/FoxF targets, the UNC-30/Pitx2 transcription factor controls GLR glia morphology and represses alternative mesodermal fates. LET-381 and UNC-30 co-expression in naive cells is sufficient for GLR glia gene expression. GLR glia inactivation by ablation or let-381 mutation disrupts locomotory behavior and promotes salt-induced paralysis, suggesting brain-neuropil activity dysregulation. Our studies uncover mechanisms of mesodermal glia development and show that like neuronal differentiation, glia differentiation requires autoregulatory terminal selector genes that define and maintain the glial fate.
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Affiliation(s)
- Nikolaos Stefanakis
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Jessica Jiang
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Yupu Liang
- Research Bioinformatics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
- Alexion Pharmaceuticals, Boston, MA, 02135, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA.
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Sun H, Beets I, Schafer W, Hobert O. Comparing engineered nuclear-localized reporter cassettes. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.001014. [PMID: 38021170 PMCID: PMC10654776 DOI: 10.17912/micropub.biology.001014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023]
Abstract
Recent single-cell transcriptome analysis has revealed a tremendous breadth and specificity of neuropeptide-encoding gene expression in the nervous system of C. elegans. To analyze the dynamics of neuropeptide gene expression, as well as to dissect the regulatory mechanism by which their expression is controlled, reporter genes remain an important tool. Using CRISPR/Cas9 genome-engineering, we generate here reporter alleles for 6 different neuropeptide encoding genes (3 flp genes, 1 nlp and 2 insulin genes). We find that different reporter cassettes result in different levels of reporter expression and recommend usage of an SL2::GFP::H2B or GFP::H2B::SL2 cassette.
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Affiliation(s)
- HaoSheng Sun
- Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
| | - Isabel Beets
- Division of Animal Physiology and Neurobiology, KU Leuven, Leuven, Flanders, Belgium
| | - William Schafer
- Division of Animal Physiology and Neurobiology, KU Leuven, Leuven, Flanders, Belgium
- Neurobiology division, MRC Laboratory of Molecular Biology, Cambridge, England, United Kingdom
| | - Oliver Hobert
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
- Biological Sciences, Columbia University, New York, New York, United States
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4
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Stefanakis N, Jiang J, Liang Y, Shaham S. LET-381/FoxF and UNC-30/Pitx2 control the development of C. elegans mesodermal glia that regulate motor behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563501. [PMID: 37961181 PMCID: PMC10634723 DOI: 10.1101/2023.10.23.563501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
While most CNS glia arise from neuroectodermal progenitors, some, like microglia, are mesodermally derived. To understand mesodermal glia development and function, we investigated C. elegans GLR glia, which ensheath the brain neuropil and separate it from the circulatory-system cavity. Transcriptome analysis suggests GLR glia merge astrocytic and endothelial characteristics relegated to separate cell types in vertebrates. Combined fate acquisition is orchestrated by LET-381/FoxF, a fate-specification/maintenance transcription factor expressed in glia and endothelia of other animals. Among LET-381/FoxF targets, UNC-30/Pitx2 transcription factor controls GLR glia morphology and represses alternative mesodermal fates. LET-381 and UNC-30 co-expression in naïve cells is sufficient for GLR glia gene expression. GLR glia inactivation by ablation or let-381 mutation disrupts locomotory behavior and induces salt hypersensitivity, suggesting brain-neuropil activity dysregulation. Our studies uncover mechanisms of mesodermal glia development and show that like neurons, glia differentiation requires autoregulatory terminal selector genes that define and maintain the glial fate.
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5
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Masoudi N, Schnabel R, Yemini E, Leyva-Díaz E, Hobert O. Cell-specific effects of the sole C. elegans Daughterless/E protein homolog, HLH-2, on nervous system development. Development 2023; 150:286219. [PMID: 36595352 PMCID: PMC10108603 DOI: 10.1242/dev.201366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/30/2022] [Indexed: 01/04/2023]
Abstract
Are there common mechanisms of neurogenesis used throughout an entire nervous system? We explored to what extent canonical proneural class I/II bHLH complexes are responsible for neurogenesis throughout the entire Caenorhabditis elegans nervous system. Distinct, lineage-specific proneural class II bHLH factors are generally thought to operate via interaction with a common, class I bHLH subunit, encoded by Daughterless in flies, the E proteins in vertebrates and HLH-2 in C. elegans. To eliminate function of all proneuronal class I/II bHLH complexes, we therefore genetically removed maternal and zygotic hlh-2 gene activity. We observed broad effects on neurogenesis, but still detected normal neurogenesis in many distinct neuron-producing lineages of the central and peripheral nervous system. Moreover, we found that hlh-2 selectively affects some aspects of neuron differentiation while leaving others unaffected. Although our studies confirm the function of proneuronal class I/II bHLH complexes in many different lineages throughout a nervous system, we conclude that their function is not universal, but rather restricted by lineage, cell type and components of differentiation programs affected.
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Affiliation(s)
- Neda Masoudi
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA
| | - Ralf Schnabel
- Institute of Genetics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Eviatar Yemini
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA.,University of Massachusetts, Department of Neurobiology, Worcester, MA 1605-2324, USA
| | - Eduardo Leyva-Díaz
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA
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Suzuki N, Zou Y, Sun H, Eichel K, Shao M, Shih M, Shen K, Chang C. Two intrinsic timing mechanisms set start and end times for dendritic arborization of a nociceptive neuron. Proc Natl Acad Sci U S A 2022; 119:e2210053119. [PMID: 36322763 PMCID: PMC9659368 DOI: 10.1073/pnas.2210053119] [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: 06/15/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022] Open
Abstract
Choreographic dendritic arborization takes place within a defined time frame, but the timing mechanism is currently not known. Here, we report that the precisely timed lin-4-lin-14 regulatory circuit triggers an initial dendritic growth activity, whereas the precisely timed lin-28-let-7-lin-41 regulatory circuit signals a subsequent developmental decline in dendritic growth ability, hence restricting dendritic arborization within a set time frame. Loss-of-function mutations in the lin-4 microRNA gene cause limited dendritic outgrowth, whereas loss-of-function mutations in its direct target, the lin-14 transcription factor gene, cause precocious and excessive outgrowth. In contrast, loss-of-function mutations in the let-7 microRNA gene prevent a developmental decline in dendritic growth ability, whereas loss-of-function mutations in its direct target, the lin-41 tripartite motif protein gene, cause further decline. lin-4 and let-7 regulatory circuits are expressed in the right place at the right time to set start and end times for dendritic arborization. Replacing the lin-4 upstream cis-regulatory sequence at the lin-4 locus with a late-onset let-7 upstream cis-regulatory sequence delays dendrite arborization, whereas replacing the let-7 upstream cis-regulatory sequence at the let-7 locus with an early-onset lin-4 upstream cis-regulatory sequence causes a precocious decline in dendritic growth ability. Our results indicate that the lin-4-lin-14 and the lin-28-let-7-lin-41 regulatory circuits control the timing of dendrite arborization through antagonistic regulation of the DMA-1 receptor level on dendrites. The LIN-14 transcription factor likely directly represses dma-1 gene expression through a transcriptional means, whereas the LIN-41 tripartite motif protein likely indirectly promotes dma-1 gene expression through a posttranscriptional means.
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Affiliation(s)
- Nobuko Suzuki
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
| | - Yan Zou
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - HaoSheng Sun
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - Kelsie Eichel
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Meiyu Shao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Mushaine Shih
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
| | - Kang Shen
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Chieh Chang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
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7
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Servello FA, Fernandes R, Eder M, Harris N, Martin OMF, Oswal N, Lindberg A, Derosiers N, Sengupta P, Stroustrup N, Apfeld J. Neuronal temperature perception induces specific defenses that enable C. elegans to cope with the enhanced reactivity of hydrogen peroxide at high temperature. eLife 2022; 11:e78941. [PMID: 36226814 PMCID: PMC9635881 DOI: 10.7554/elife.78941] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 10/12/2022] [Indexed: 11/30/2022] Open
Abstract
Hydrogen peroxide is the most common reactive chemical that organisms face on the microbial battlefield. The rate with which hydrogen peroxide damages biomolecules required for life increases with temperature, yet little is known about how organisms cope with this temperature-dependent threat. Here, we show that Caenorhabditis elegans nematodes use temperature information perceived by sensory neurons to cope with the temperature-dependent threat of hydrogen peroxide produced by the pathogenic bacterium Enterococcus faecium. These nematodes preemptively induce the expression of specific hydrogen peroxide defenses in response to perception of high temperature by a pair of sensory neurons. These neurons communicate temperature information to target tissues expressing those defenses via an insulin/IGF1 hormone. This is the first example of a multicellular organism inducing their defenses to a chemical when they sense an inherent enhancer of the reactivity of that chemical.
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Affiliation(s)
| | - Rute Fernandes
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Matthias Eder
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Nathan Harris
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Olivier MF Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Natasha Oswal
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Anders Lindberg
- Biology Department, Northeastern UniversityBostonUnited States
| | | | - Piali Sengupta
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Nicholas Stroustrup
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Javier Apfeld
- Biology Department, Northeastern UniversityBostonUnited States
- Bioengineering Department, Northeastern UniversityBostonUnited States
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8
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Segref A, Vakkayil KL, Padvitski T, Li Q, Kroef V, Lormann J, Körner L, Finger F, Hoppe T. Thermosensation in Caenorhabditis elegans is linked to ubiquitin-dependent protein turnover via insulin and calcineurin signalling. Nat Commun 2022; 13:5874. [PMID: 36198694 PMCID: PMC9534930 DOI: 10.1038/s41467-022-33467-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 09/16/2022] [Indexed: 11/21/2022] Open
Abstract
Organismal physiology and survival are influenced by environmental conditions and linked to protein quality control. Proteome integrity is achieved by maintaining an intricate balance between protein folding and degradation. In Caenorhabditis elegans, acute heat stress determines cell non-autonomous regulation of chaperone levels. However, how the perception of environmental changes, including physiological temperature, affects protein degradation remains largely unexplored. Here, we show that loss-of-function of dyf-1 in Caenorhabditis elegans associated with dysfunctional sensory neurons leads to defects in both temperature perception and thermal adaptation of the ubiquitin/proteasome system centered on thermosensory AFD neurons. Impaired perception of moderate temperature changes worsens ubiquitin-dependent proteolysis in intestinal cells. Brain-gut communication regulating protein turnover is mediated by upregulation of the insulin-like peptide INS-5 and inhibition of the calcineurin-regulated forkhead-box transcription factor DAF-16/FOXO. Our data indicate that perception of ambient temperature and its neuronal integration is important for the control of proteome integrity in complex organisms.
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Affiliation(s)
- Alexandra Segref
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany.
| | - Kavya L Vakkayil
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Tsimafei Padvitski
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Qiaochu Li
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Virginia Kroef
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
- Max Planck Institute for Biology of Ageing, 50931, Cologne, Germany
| | - Jakob Lormann
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Lioba Körner
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Fabian Finger
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Thorsten Hoppe
- Institute for Genetics, University of Cologne, 50674, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital of Cologne, 50931, Cologne, Germany.
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Riedl J, Fieseler C, Zimmer M. Tyraminergic corollary discharge filters reafferent perception in a chemosensory neuron. Curr Biol 2022; 32:3048-3058.e6. [PMID: 35690069 DOI: 10.1016/j.cub.2022.05.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 12/25/2022]
Abstract
Interpreting sensory information requires its integration with the current behavior of the animal. However, how motor-related circuits influence sensory information processing is incompletely understood. Here, we report that current locomotor state directly modulates the activity of BAG CO2 sensory neurons in Caenorhabditis elegans. By recording neuronal activity in animals freely navigating CO2 landscapes, we found that during reverse crawling states, BAG activity is suppressed by tyraminergic corollary discharge signaling. We provide genetic evidence that tyramine released from the RIM reversal interneurons extrasynaptically activates the inhibitory chloride channel LGC-55 in BAG. Disrupting this pathway genetically leads to excessive behavioral responses to CO2 stimuli. Moreover, we find that LGC-55 signaling cancels out perception of self-produced CO2 and O2 stimuli when animals reverse into their own gas plume in ethologically relevant aqueous environments. Our results show that sensorimotor integration involves corollary discharge signals directly modulating chemosensory neurons.
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Affiliation(s)
- Julia Riedl
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Charles Fieseler
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Manuel Zimmer
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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10
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Tomioka M, Jang MS, Iino Y. DAF-2c signaling promotes taste avoidance after starvation in Caenorhabditis elegans by controlling distinct phospholipase C isozymes. Commun Biol 2022; 5:30. [PMID: 35017611 PMCID: PMC8752840 DOI: 10.1038/s42003-021-02956-8] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 12/09/2021] [Indexed: 12/19/2022] Open
Abstract
Previously, we reported that DAF-2c, an axonal insulin receptor isoform in Caenorhabditis elegans, acts in the ASER gustatory neuron to regulate taste avoidance learning, a process in which worms learn to avoid salt concentrations experienced during starvation. Here, we show that secretion of INS-1, an insulin-like peptide, after starvation conditioning is sufficient to drive taste avoidance via DAF-2c signaling. Starvation conditioning enhances the salt-triggered activity of AIA neurons, the main sites of INS-1 release, which potentially promotes feedback signaling to ASER to maintain DAF-2c activity during taste avoidance. Genetic studies suggest that DAF-2c-Akt signaling promotes high-salt avoidance via a decrease in PLCβ activity. On the other hand, the DAF-2c pathway promotes low-salt avoidance via PLCε and putative Akt phosphorylation sites on PLCε are essential for taste avoidance. Our findings imply that animals disperse from the location at which they experience starvation by controlling distinct PLC isozymes via DAF-2c.
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Affiliation(s)
- Masahiro Tomioka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Moon Sun Jang
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Aichi, 464-8602, Japan
| | - Yuichi Iino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
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11
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Temporal transitions in the post-mitotic nervous system of Caenorhabditis elegans. Nature 2021; 600:93-99. [PMID: 34759317 PMCID: PMC8785361 DOI: 10.1038/s41586-021-04071-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 09/29/2021] [Indexed: 01/03/2023]
Abstract
In most animals, the majority of the nervous system is generated and assembled into neuronal circuits during embryonic development1. However, during juvenile stages, nervous systems still undergo extensive anatomical and functional changes to eventually form a fully mature nervous system by the adult stage2,3. The molecular changes in post-mitotic neurons across post-embryonic development and the genetic programs that control these temporal transitions are not well understood4,5. Here, using the model system Caenorhabditis elegans, we comprehensively characterized the distinct functional states (locomotor behaviour) and the corresponding distinct molecular states (transcriptome) of the post-mitotic nervous system across temporal transitions during post-embryonic development. We observed pervasive, neuron-type-specific changes in gene expression, many of which are controlled by the developmental upregulation of the conserved heterochronic microRNA LIN-4 and the subsequent promotion of a mature neuronal transcriptional program through the repression of its target, the transcription factor lin-14. The functional relevance of these molecular transitions are exemplified by a temporally regulated target gene of the LIN-14 transcription factor, nlp-45, a neuropeptide-encoding gene, which we find is required for several distinct temporal transitions in exploratory activity during post-embryonic development. Our study provides insights into regulatory strategies that control neuron-type-specific gene batteries to modulate distinct behavioural states across temporal, sexual and environmental dimensions of post-embryonic development.
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12
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Opponent vesicular transporters regulate the strength of glutamatergic neurotransmission in a C. elegans sensory circuit. Nat Commun 2021; 12:6334. [PMID: 34732711 PMCID: PMC8566550 DOI: 10.1038/s41467-021-26575-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/22/2021] [Indexed: 11/30/2022] Open
Abstract
At chemical synapses, neurotransmitters are packaged into synaptic vesicles that release their contents in response to depolarization. Despite its central role in synaptic function, regulation of the machinery that loads vesicles with neurotransmitters remains poorly understood. We find that synaptic glutamate signaling in a C. elegans chemosensory circuit is regulated by antagonistic interactions between the canonical vesicular glutamate transporter EAT-4/VGLUT and another vesicular transporter, VST-1. Loss of VST-1 strongly potentiates glutamate release from chemosensory BAG neurons and disrupts chemotaxis behavior. Analysis of the circuitry downstream of BAG neurons shows that excess glutamate release disrupts behavior by inappropriately recruiting RIA interneurons to the BAG-associated chemotaxis circuit. Our data indicate that in vivo the strength of glutamatergic synapses is controlled by regulation of neurotransmitter packaging into synaptic vesicles via functional coupling of VGLUT and VST-1. The authors describe a vesicular transporter, VST-1, that is required in glutamatergic chemosensory neurons for chemotactic avoidance behavior in C. elegans. VST-1 antagonizes VGLUT-dependent packaging of glutamate into synaptic vesicles and determines the strength of synaptic glutamate signaling.
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Vuong-Brender TT, Flynn S, Vallis Y, de Bono M. Neuronal calmodulin levels are controlled by CAMTA transcription factors. eLife 2021; 10:68238. [PMID: 34499028 PMCID: PMC8428840 DOI: 10.7554/elife.68238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/28/2021] [Indexed: 01/18/2023] Open
Abstract
The ubiquitous Ca2+ sensor calmodulin (CaM) binds and regulates many proteins, including ion channels, CaM kinases, and calcineurin, according to Ca2+-CaM levels. What regulates neuronal CaM levels, is, however, unclear. CaM-binding transcription activators (CAMTAs) are ancient proteins expressed broadly in nervous systems and whose loss confers pleiotropic behavioral defects in flies, mice, and humans. Using Caenorhabditis elegans and Drosophila, we show that CAMTAs control neuronal CaM levels. The behavioral and neuronal Ca2+ signaling defects in mutants lacking camt-1, the sole C. elegans CAMTA, can be rescued by supplementing neuronal CaM. CAMT-1 binds multiple sites in the CaM promoter and deleting these sites phenocopies camt-1. Our data suggest CAMTAs mediate a conserved and general mechanism that controls neuronal CaM levels, thereby regulating Ca2+ signaling, physiology, and behavior.
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Affiliation(s)
- Thanh Thi Vuong-Brender
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Sean Flynn
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Yvonne Vallis
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mario de Bono
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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14
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Cadena Del Castillo CE, Hannich JT, Kaech A, Chiyoda H, Brewer J, Fukuyama M, Færgeman NJ, Riezman H, Spang A. Patched regulates lipid homeostasis by controlling cellular cholesterol levels. Nat Commun 2021; 12:4898. [PMID: 34385431 PMCID: PMC8361143 DOI: 10.1038/s41467-021-24995-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 07/11/2021] [Indexed: 02/07/2023] Open
Abstract
Hedgehog (Hh) signaling is essential during development and in organ physiology. In the canonical pathway, Hh binding to Patched (PTCH) relieves the inhibition of Smoothened (SMO). Yet, PTCH may also perform SMO-independent functions. While the PTCH homolog PTC-3 is essential in C. elegans, worms lack SMO, providing an excellent model to probe non-canonical PTCH function. Here, we show that PTC-3 is a cholesterol transporter. ptc-3(RNAi) leads to accumulation of intracellular cholesterol and defects in ER structure and lipid droplet formation. These phenotypes were accompanied by a reduction in acyl chain (FA) length and desaturation. ptc-3(RNAi)-induced lethality, fat content and ER morphology defects were rescued by reducing dietary cholesterol. We provide evidence that cholesterol accumulation modulates the function of nuclear hormone receptors such as of the PPARα homolog NHR-49 and NHR-181, and affects FA composition. Our data uncover a role for PTCH in organelle structure maintenance and fat metabolism.
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Affiliation(s)
| | - J Thomas Hannich
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Hirohisa Chiyoda
- Laboratory of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Jonathan Brewer
- Department of Biochemistry and Molecular Biology, Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Masamitsu Fukuyama
- Laboratory of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Nils J Færgeman
- Department of Biochemistry and Molecular Biology, Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Howard Riezman
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Anne Spang
- Biozentrum, University of Basel, Basel, Switzerland.
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15
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Labonté B, Abdallah K, Maussion G, Yerko V, Yang J, Bittar T, Quessy F, Golden SA, Navarro L, Checknita D, Gigek C, Lopez JP, Neve RL, Russo SJ, Tremblay RE, Côté G, Meaney MJ, Mechawar N, Nestler EJ, Turecki G. Regulation of impulsive and aggressive behaviours by a novel lncRNA. Mol Psychiatry 2021; 26:3751-3764. [PMID: 31907380 PMCID: PMC7436429 DOI: 10.1038/s41380-019-0637-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 12/15/2022]
Abstract
High impulsive and aggressive traits associate with poor behavioural self-control. Despite their importance in predicting behavioural negative outcomes including suicide, the molecular mechanisms underlying the expression of impulsive and aggressive traits remain poorly understood. Here, we identified and characterized a novel long noncoding RNA (lncRNA), acting as a regulator of the monoamine oxidase A (MAOA) gene in the brain, and named it MAOA-associated lncRNA (MAALIN). Our results show that in the brain of suicide completers, MAALIN is regulated by a combination of epigenetic mechanisms including DNA methylation and chromatin modifications. Elevated MAALIN in the dentate gyrus of impulsive-aggressive suicides was associated with lower MAOA expression. Viral overexpression of MAALIN in neuroprogenitor cells decreased MAOA expression while CRISPR-mediated knock out resulted in elevated MAOA expression. Using viral-mediated gene transfer, we confirmed that MAALIN in the hippocampus significantly decreases MAOA expression and exacerbates the expression of impulsive-aggressive behavioural traits in CD1 aggressive mice. Overall, our findings suggest that variations in DNA methylation mediate the differential expression of a novel lncRNA that acts on MAOA expression to regulate impulsive-aggressive behaviours.
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Affiliation(s)
- Benoit Labonté
- Centre de Recherche CERVO, Department of Neuroscience and Psychiatry, Laval University, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.
| | - Khaled Abdallah
- Centre de Recherche CERVO, Department of Neuroscience and Psychiatry, Laval University, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Gilles Maussion
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Volodymyr Yerko
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Jennie Yang
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Thibault Bittar
- Centre de Recherche CERVO, Department of Neuroscience and Psychiatry, Laval University, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Francis Quessy
- Centre de Recherche CERVO, Department of Neuroscience and Psychiatry, Laval University, 2601, Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Sam A Golden
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Luis Navarro
- Unitat de Genètica Molecular Institut de Biomedicina de València, Valencia, Spain
| | - Dave Checknita
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Carolina Gigek
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Juan Pablo Lopez
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Rachael L Neve
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Scott J Russo
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Richard E Tremblay
- Research Unit on Children's Psychosocial Maladjustment, Université de Montréal, Montreal, QC, Canada
| | - Gilles Côté
- Philippe-Pinel Institute of Montreal, University of Montreal, Montreal, QC, Canada
| | - Michael J Meaney
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
- Ludmer Centre for Neuroinformatics and Mental Health, McGill University, Montreal, QC, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada
| | - Eric J Nestler
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Research Centre, Department of Psychiatry, McGill University, Frank B. Common Pavilion, 6875 LaSalle Blvd., Montreal, QC, H4H 1R3, Canada.
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16
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Chiyoda H, Kume M, del Castillo CC, Kontani K, Spang A, Katada T, Fukuyama M. Caenorhabditis elegans PTR/PTCHD PTR-18 promotes the clearance of extracellular hedgehog-related protein via endocytosis. PLoS Genet 2021; 17:e1009457. [PMID: 33872306 PMCID: PMC8104386 DOI: 10.1371/journal.pgen.1009457] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 05/07/2021] [Accepted: 03/01/2021] [Indexed: 01/25/2023] Open
Abstract
Spatiotemporal restriction of signaling plays a critical role in animal development and tissue homeostasis. All stem and progenitor cells in newly hatched C. elegans larvae are quiescent and capable of suspending their development until sufficient food is supplied. Here, we show that ptr-18, which encodes the evolutionarily conserved patched-related (PTR)/patched domain-containing (PTCHD) protein, temporally restricts the availability of extracellular hedgehog-related protein to establish the capacity of progenitor cells to maintain quiescence. We found that neural progenitor cells exit from quiescence in ptr-18 mutant larvae even when hatched under starved conditions. This unwanted reactivation depended on the activity of a specific set of hedgehog-related grl genes including grl-7. Unexpectedly, neither PTR-18 nor GRL-7 were expressed in newly hatched wild-type larvae. Instead, at the late embryonic stage, both PTR-18 and GRL-7 proteins were first localized around the apical membrane of hypodermal and neural progenitor cells and subsequently targeted for lysosomal degradation before hatching. Loss of ptr-18 caused a significant delay in GRL-7 clearance, causing this protein to be retained in the extracellular space in newly hatched ptr-18 mutant larvae. Furthermore, the putative transporter activity of PTR-18 was shown to be required for the appropriate function of the protein. These findings not only uncover a previously undescribed role of PTR/PTCHD in the clearance of extracellular hedgehog-related proteins via endocytosis-mediated degradation but also illustrate that failure to temporally restrict intercellular signaling during embryogenesis can subsequently compromise post-embryonic progenitor cell function.
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Affiliation(s)
- Hirohisa Chiyoda
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Masahiko Kume
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | | | - Kenji Kontani
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Anne Spang
- Biozentrum, University of Basel, Basel, Switzerland
| | - Toshiaki Katada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Masamitsu Fukuyama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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17
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Abrams J, Nance J. A polarity pathway for exocyst-dependent intracellular tube extension. eLife 2021; 10:65169. [PMID: 33687331 PMCID: PMC8021397 DOI: 10.7554/elife.65169] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/08/2021] [Indexed: 12/25/2022] Open
Abstract
Lumen extension in intracellular tubes can occur when vesicles fuse with an invading apical membrane. Within the Caenorhabditis elegans excretory cell, which forms an intracellular tube, the exocyst vesicle-tethering complex is enriched at the lumenal membrane and is required for its outgrowth, suggesting that exocyst-targeted vesicles extend the lumen. Here, we identify a pathway that promotes intracellular tube extension by enriching the exocyst at the lumenal membrane. We show that PAR-6 and PKC-3/aPKC concentrate at the lumenal membrane and promote lumen extension. Using acute protein depletion, we find that PAR-6 is required for exocyst membrane recruitment, whereas PAR-3, which can recruit the exocyst in mammals, appears dispensable for exocyst localization and lumen extension. Finally, we show that CDC-42 and RhoGEF EXC-5/FGD regulate lumen extension by recruiting PAR-6 and PKC-3 to the lumenal membrane. Our findings reveal a pathway that connects CDC-42, PAR proteins, and the exocyst to extend intracellular tubes.
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Affiliation(s)
- Joshua Abrams
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York, United States
| | - Jeremy Nance
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York, United States.,Department of Cell Biology, NYU Grossman School of Medicine, New York, United States
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18
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Kazmierczak M, Farré i Díaz C, Ofenbauer A, Herzog S, Tursun B. The CONJUDOR pipeline for multiplexed knockdown of gene pairs identifies RBBP-5 as a germ cell reprogramming barrier in C. elegans. Nucleic Acids Res 2021; 49:e22. [PMID: 33290523 PMCID: PMC7913679 DOI: 10.1093/nar/gkaa1171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/12/2020] [Accepted: 11/17/2020] [Indexed: 12/05/2022] Open
Abstract
Multiple gene activities control complex biological processes such as cell fate specification during development and cellular reprogramming. Investigating the manifold gene functions in biological systems requires also simultaneous depletion of two or more gene activities. RNA interference-mediated knockdown (RNAi) is commonly used in Caenorhabditis elegans to assess essential genes, which otherwise lead to lethality or developmental arrest upon full knockout. RNAi application is straightforward by feeding worms with RNAi plasmid-containing bacteria. However, the general approach of mixing bacterial RNAi clones to deplete two genes simultaneously often yields poor results. To address this issue, we developed a bacterial conjugation-mediated double RNAi technique 'CONJUDOR'. It allows combining RNAi bacteria for robust double RNAi with high-throughput. To demonstrate the power of CONJUDOR for large scale double RNAi screens we conjugated RNAi against the histone chaperone gene lin-53 with more than 700 other chromatin factor genes. Thereby, we identified the Set1/MLL methyltransferase complex member RBBP-5 as a novel germ cell reprogramming barrier. Our findings demonstrate that CONJUDOR increases efficiency and versatility of RNAi screens to examine interconnected biological processes in C. elegans with high-throughput.
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Affiliation(s)
- Marlon Kazmierczak
- Berlin Institute for Medical Systems Biology, Berlin 10115, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Carlota Farré i Díaz
- Berlin Institute for Medical Systems Biology, Berlin 10115, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Andreas Ofenbauer
- Berlin Institute for Medical Systems Biology, Berlin 10115, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Sergej Herzog
- Berlin Institute for Medical Systems Biology, Berlin 10115, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Baris Tursun
- Berlin Institute for Medical Systems Biology, Berlin 10115, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
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19
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Ahier A, Suman SK, Jarriault S. Gene bashing of ceh-6 locus identifies genomic regions important for ceh-6 rectal cell expression and rescue of its mutant lethality. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 33364555 PMCID: PMC7753896 DOI: 10.17912/micropub.biology.000339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Strong loss-of-function or null mutants can sometimes lead to a penetrant early lethality, impairing the study of these genes’ function. This is the case for the ceh-6 null mutant, which exhibits 100% penetrant lethality. Here, we describe how we used gene bashing to identify distinct regulatory regions in the ceh-6 locus. This allowed us to generate a ceh-6 null strain that is viable and still displays ceh-6 mutant Y-to-PDA transdifferentiation phenotype. Such strategy can be applied to many other mutants impacting viability.
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Affiliation(s)
- Arnaud Ahier
- IGBMC, Development and Stem Cells Department, CNRS UMR7104, INSERM U1258, Université de Strasbourg, Illkirch CU Strasbourg, 67404 France.,current address: Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Shashi Kumar Suman
- IGBMC, Development and Stem Cells Department, CNRS UMR7104, INSERM U1258, Université de Strasbourg, Illkirch CU Strasbourg, 67404 France
| | - Sophie Jarriault
- IGBMC, Development and Stem Cells Department, CNRS UMR7104, INSERM U1258, Université de Strasbourg, Illkirch CU Strasbourg, 67404 France
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20
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Guo X, Yuan J, Song X, Wang X, Sun Q, Tian J, Li X, Ding M, Liu Y. Bacteria metabolites from Peganum harmala L. polysaccharides inhibits polyQ aggregation through proteasome-mediated protein degradation in C. elegans. Int J Biol Macromol 2020; 161:681-691. [PMID: 32544588 DOI: 10.1016/j.ijbiomac.2020.06.091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/30/2020] [Accepted: 06/10/2020] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is a relentlessly progressive neurodegenerative disease featured by the over-expanded polyglutamine (polyQ)-induced protein aggregation. Using Caenorhabditis elegans (C. elegans) as a model system, we show that water soluble polysaccharide extracted from the herb Peganum harmala L. (PS1) not only reduces polyQ aggregation but also alleviates the associated neurotoxicity. Genetic and pharmacologic analysis suggested that PS1 treatment acts though proteasome-mediated protein degradation pathway to inhibit polyQ aggregation. Notably, the efficacy of PS1 is aroused specifically by co-incubation with live Escherichia coli OP50, which is the sole food source for worms. Further UPLC-Q-TOF/MS analysis determined the bioactivity of polyQ inhibition, which is composed of several oligosaccharides, including stachyoses, verbascoses, trisaccharides and tetrasaccharides composed of galacturonic acids. Together, our study revealed a potential drug target for further HD treatment and pinpointed the possibility that the secreted metabolites produced from bacteria treated with various compounds may provide direct beneficial effect to human bodies.
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Affiliation(s)
- Xiaoyu Guo
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Jiang Yuan
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Xingzhuo Song
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Xirui Wang
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Qianqian Sun
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Jingyun Tian
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Xia Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Mei Ding
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yonggang Liu
- Beijing University of Chinese Medicine, Beijing 102488, China.
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21
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Charest J, Daniele T, Wang J, Bykov A, Mandlbauer A, Asparuhova M, Röhsner J, Gutiérrez-Pérez P, Cochella L. Combinatorial Action of Temporally Segregated Transcription Factors. Dev Cell 2020; 55:483-499.e7. [PMID: 33002421 PMCID: PMC7704111 DOI: 10.1016/j.devcel.2020.09.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/30/2020] [Accepted: 09/01/2020] [Indexed: 01/05/2023]
Abstract
Combinatorial action of transcription factors (TFs) with partially overlapping expression is a widespread strategy to generate novel gene-expression patterns and, thus, cellular diversity. Known mechanisms underlying combinatorial activity require co-expression of TFs within the same cell. Here, we describe the mechanism by which two TFs that are never co-expressed generate a new, intersectional expression pattern in C. elegans embryos: lineage-specific priming of a gene by a transiently expressed TF generates a unique intersection with a second TF acting on the same gene four cell divisions later; the second TF is expressed in multiple cells but only activates transcription in those where priming occurred. Early induction of active transcription is necessary and sufficient to establish a competent state, maintained by broadly expressed regulators in the absence of the initial trigger. We uncover additional cells diversified through this mechanism. Our findings define a mechanism for combinatorial TF activity with important implications for generation of cell-type diversity. Lineage-specific priming enables asymmetric gene expression in L/R neuron pairs Transient, lineage-specific TFs prime a locus for later activation by a bilateral TF An early active transcriptional state is necessary and sufficient for priming Maintenance of asymmetric primed state occurs in a symmetric regulatory environment
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Affiliation(s)
- Julien Charest
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Thomas Daniele
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Jingkui Wang
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Aleksandr Bykov
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Ariane Mandlbauer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Mila Asparuhova
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Josef Röhsner
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Paula Gutiérrez-Pérez
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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22
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Luo KL, Underwood RS, Greenwald I. Positive autoregulation of lag-1 in response to LIN-12 activation in cell fate decisions during C. elegans reproductive system development. Development 2020; 147:dev.193482. [PMID: 32839181 DOI: 10.1242/dev.193482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/11/2020] [Indexed: 12/11/2022]
Abstract
During animal development, ligand binding releases the intracellular domain of LIN-12/Notch by proteolytic cleavage to translocate to the nucleus, where it associates with the DNA-binding protein LAG-1/CSL to activate target gene transcription. We investigated the spatiotemporal regulation of LAG-1/CSL expression in Caenorhabditis elegans and observed that an increase in endogenous LAG-1 levels correlates with LIN-12/Notch activation in different cell contexts during reproductive system development. We show that this increase is via transcriptional upregulation by creating a synthetic endogenous operon, and identified an enhancer region that contains multiple LAG-1 binding sites (LBSs) embedded in a more extensively conserved high occupancy target (HOT) region. We show that these LBSs are necessary for upregulation in response to LIN-12/Notch activity, indicating that lag-1 engages in direct positive autoregulation. Deletion of the HOT region from endogenous lag-1 reduced LAG-1 levels and abrogated positive autoregulation, but did not cause hallmark cell fate transformations associated with loss of lin-12/Notch or lag-1 activity. Instead, later somatic reproductive system defects suggest that proper transcriptional regulation of lag-1 confers robustness to somatic reproductive system development.
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Affiliation(s)
- Katherine Leisan Luo
- Integrated Program in Cellular, Molecular and Biophysical Studies, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Ryan S Underwood
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Iva Greenwald
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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23
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Cellular Expression and Functional Roles of All 26 Neurotransmitter GPCRs in the C. elegans Egg-Laying Circuit. J Neurosci 2020; 40:7475-7488. [PMID: 32847964 DOI: 10.1523/jneurosci.1357-20.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/28/2020] [Accepted: 08/13/2020] [Indexed: 01/06/2023] Open
Abstract
Maps of the synapses made and neurotransmitters released by all neurons in model systems, such as Caenorhabditis elegans have left still unresolved how neural circuits integrate and respond to neurotransmitter signals. Using the egg-laying circuit of C. elegans as a model, we mapped which cells express each of the 26 neurotransmitter GPCRs of this organism and also genetically analyzed the functions of all 26 GPCRs. We found that individual neurons express many distinct receptors, epithelial cells often express neurotransmitter receptors, and receptors are often positioned to receive extrasynaptic signals. Receptor knockouts reveal few egg-laying defects under standard laboratory conditions, suggesting that the receptors function redundantly or regulate egg-laying only in specific conditions; however, increasing receptor signaling through overexpression more efficiently reveals receptor functions. This map of neurotransmitter GPCR expression and function in the egg-laying circuit provides a model for understanding GPCR signaling in other neural circuits.SIGNIFICANCE STATEMENT Neurotransmitters signal through GPCRs to modulate activity of neurons, and changes in such signaling can underlie conditions such as depression and Parkinson's disease. To determine how neurotransmitter GPCRs together help regulate function of a neural circuit, we analyzed the simple egg-laying circuit in the model organism C. elegans We identified all the cells that express every neurotransmitter GPCR and genetically analyzed how each GPCR affects the behavior the circuit produces. We found that many neurotransmitter GPCRs are expressed in each neuron, that neurons also appear to use these receptors to communicate with other cell types, and that GPCRs appear to often act redundantly or only under specific conditions to regulate circuit function.
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Buzzi L, Segobia VA, Rayes D, Castro OA. The ER glycoprotein folding sensor UDP-Glc: glycoprotein glucosyltransferase is broadly expressed in C. elegans hermaphrodite. MICROPUBLICATION BIOLOGY 2020; 2020:10.17912/micropub.biology.000299. [PMID: 32885150 PMCID: PMC7456565 DOI: 10.17912/micropub.biology.000299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lucila Buzzi
- Fundación Instituto Leloir, Buenos Aires, Argentina
| | - Victoria Ayelen Segobia
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Diego Rayes
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (CONICET),
Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Olga A Castro
- Consejo Nacional de Investigaciones Científicas y Técnicas ,
Instituto de Biociencias, Biotecnología y Biología traslacional, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina,
Correspondence to: Olga A Castro ()
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25
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Fadda M, De Fruyt N, Borghgraef C, Watteyne J, Peymen K, Vandewyer E, Naranjo Galindo FJ, Kieswetter A, Mirabeau O, Chew YL, Beets I, Schoofs L. NPY/NPF-Related Neuropeptide FLP-34 Signals from Serotonergic Neurons to Modulate Aversive Olfactory Learning in Caenorhabditis elegans. J Neurosci 2020; 40:6018-6034. [PMID: 32576621 PMCID: PMC7392509 DOI: 10.1523/jneurosci.2674-19.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 04/26/2020] [Accepted: 06/12/2020] [Indexed: 02/03/2023] Open
Abstract
Aversive learning is fundamental for animals to increase chances of survival. In addition to classical neurotransmitters, neuropeptides have emerged to modulate such complex behaviors. Among them, neuropeptide Y (NPY) is well known to promote aversive memory acquisition in mammals. Here we identify an NPY/neuropeptide F (NPF)-related neuropeptide system in Caenorhabditis elegans and show that this FLP-34/NPR-11 system is required for learning negative associations, a process that is reminiscent of NPY signaling in mammals. The Caenorhabditis elegans NPY/NPF ortholog FLP-34 displays conserved structural hallmarks of bilaterian-wide NPY/NPF neuropeptides. We show that it is required for aversive olfactory learning after pairing diacetyl with the absence of food, but not for appetitive olfactory learning in response to butanone. To mediate diacetyl learning and thus integrate the aversive food context with the diacetyl odor, FLP-34 is released from serotonergic neurons and signals through its evolutionarily conserved NPY/NPF GPCR, NPR-11, in downstream AIA interneurons. NPR-11 activation in the AIA integration center results in avoidance of a previously attractive stimulus. This study opens perspectives for a deeper understanding of stress conditions in which aversive learning results in excessive avoidance.SIGNIFICANCE STATEMENT Aversive learning evolved early in evolution to promote avoidance of dangerous and stressful situations. In addition to classical neurotransmitters, neuropeptides are emerging as modulators of complex behaviors, including learning and memory. Here, we identified the evolutionary ortholog of neuropeptide Y/neuropeptide F in the nematode Caenorhabditis elegans, and we discovered that it is required for olfactory aversive learning. In addition, we elucidated the neural circuit underlying this avoidance behavior, and we discovered a novel coordinated action of Caenorhabditis elegans neuropeptide Y/neuropeptide F and serotonin that could aid in our understanding of the molecular mechanisms underlying stress disorders in which excessive avoidance results in maladaptive behaviors.
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Affiliation(s)
- Melissa Fadda
- Department of Biology, KU Leuven, Leuven, 3000, Belgium
| | | | | | - Jan Watteyne
- Department of Biology, KU Leuven, Leuven, 3000, Belgium
| | | | | | | | | | - Olivier Mirabeau
- Genetics and Biology of Cancers Unit, Institut Curie, Institut National de la Santé et de la Recherche Médicale U830, Paris Sciences et Lettres Research University, Paris, 75005, France
| | - Yee Lian Chew
- Illawarra Health & Medical Research Institute School of Chemistry & Molecular Bioscience, University of Wollongong, Wollongong, 2522 New South Wales, Australia
| | - Isabel Beets
- Department of Biology, KU Leuven, Leuven, 3000, Belgium
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26
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Barro-Trastoy D, Carrera E, Baños J, Palau-Rodríguez J, Ruiz-Rivero O, Tornero P, Alonso JM, López-Díaz I, Gómez MD, Pérez-Amador MA. Regulation of ovule initiation by gibberellins and brassinosteroids in tomato and Arabidopsis: two plant species, two molecular mechanisms. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:1026-1041. [PMID: 31930587 DOI: 10.1111/tpj.14684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/18/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Ovule primordia formation is a complex developmental process with a strong impact on the production of seeds. In Arabidopsis this process is controlled by a gene network, including components of the signalling pathways of auxin, brassinosteroids (BRs) and cytokinins. Recently, we have shown that gibberellins (GAs) also play an important role in ovule primordia initiation, inhibiting ovule formation in both Arabidopsis and tomato. Here we reveal that BRs also participate in the control of ovule initiation in tomato, by promoting an increase on ovule primordia formation. Moreover, molecular and genetic analyses of the co-regulation by GAs and BRs of the control of ovule initiation indicate that two different mechanisms occur in tomato and Arabidopsis. In tomato, GAs act downstream of BRs. BRs regulate ovule number through the downregulation of GA biosynthesis, which provokes stabilization of DELLA proteins that will finally promote ovule primordia initiation. In contrast, in Arabidopsis both GAs and BRs regulate ovule number independently of the activity levels of the other hormone. Taken together, our data strongly suggest that different molecular mechanisms could operate in different plant species to regulate identical developmental processes even, as for ovule primordia initiation, if the same set of hormones trigger similar responses, adding a new level of complexity.
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Affiliation(s)
- Daniela Barro-Trastoy
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - Esther Carrera
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - Jorge Baños
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - Julia Palau-Rodríguez
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - Omar Ruiz-Rivero
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - Pablo Tornero
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - José M Alonso
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State, Raleigh, NC, USA
| | - Isabel López-Díaz
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - María Dolores Gómez
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | - Miguel A Pérez-Amador
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), CPI 8E, Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
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Modular Organization of Cis-regulatory Control Information of Neurotransmitter Pathway Genes in Caenorhabditis elegans. Genetics 2020; 215:665-681. [PMID: 32444379 DOI: 10.1534/genetics.120.303206] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/20/2020] [Indexed: 11/18/2022] Open
Abstract
We explore here the cis-regulatory logic that dictates gene expression in specific cell types in the nervous system. We focus on a set of eight genes involved in the synthesis, transport, and breakdown of three neurotransmitter systems: acetylcholine (unc-17 /VAChT, cha-1 /ChAT, cho-1 /ChT, and ace-2 /AChE), glutamate (eat-4 /VGluT), and γ-aminobutyric acid (unc-25 /GAD, unc-46 /LAMP, and unc-47 /VGAT). These genes are specifically expressed in defined subsets of cells in the nervous system. Through transgenic reporter gene assays, we find that the cellular specificity of expression of all of these genes is controlled in a modular manner through distinct cis-regulatory elements, corroborating the previously inferred piecemeal nature of specification of neurotransmitter identity. This modularity provides the mechanistic basis for the phenomenon of "phenotypic convergence," in which distinct regulatory pathways can generate similar phenotypic outcomes (i.e., the acquisition of a specific neurotransmitter identity) in different neuron classes. We also identify cases of enhancer pleiotropy, in which the same cis-regulatory element is utilized to control gene expression in distinct neuron types. We engineered a cis-regulatory allele of the vesicular acetylcholine transporter, unc-17 /VAChT, to assess the functional contribution of a "shadowed" enhancer. We observed a selective loss of unc-17 /VAChT expression in one cholinergic pharyngeal pacemaker motor neuron class and a behavioral phenotype that matches microsurgical removal of this neuron. Our analysis illustrates the value of understanding cis-regulatory information to manipulate gene expression and control animal behavior.
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Kaur S, Mélénec P, Murgan S, Bordet G, Recouvreux P, Lenne PF, Bertrand V. Wnt ligands regulate the asymmetric divisions of neuronal progenitors in C. elegans embryos. Development 2020; 147:dev183186. [PMID: 32156756 PMCID: PMC10679509 DOI: 10.1242/dev.183186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 02/25/2020] [Indexed: 12/12/2022]
Abstract
Wnt/β-catenin signalling has been implicated in the terminal asymmetric divisions of neuronal progenitors in vertebrates and invertebrates. However, the role of Wnt ligands in this process remains poorly characterized. Here, we used the terminal divisions of the embryonic neuronal progenitors in C. elegans to characterize the role of Wnt ligands during this process, focusing on a lineage that produces the cholinergic interneuron AIY. We observed that, during interphase, the neuronal progenitor is elongated along the anteroposterior axis, then divides along its major axis, generating an anterior and a posterior daughter with different fates. Using time-controlled perturbations, we show that three Wnt ligands, which are transcribed at higher levels at the posterior of the embryo, regulate the orientation of the neuronal progenitor and its asymmetric division. We also identify a role for a Wnt receptor (MOM-5) and a cortical transducer APC (APR-1), which are, respectively, enriched at the posterior and anterior poles of the neuronal progenitor. Our study establishes a role for Wnt ligands in the regulation of the shape and terminal asymmetric divisions of neuronal progenitors, and identifies downstream components.
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Affiliation(s)
- Shilpa Kaur
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
| | - Pauline Mélénec
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
| | - Sabrina Murgan
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
| | - Guillaume Bordet
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
| | - Pierre Recouvreux
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
| | - Pierre-François Lenne
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
| | - Vincent Bertrand
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille 13009, France
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29
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Brumos J, Zhao C, Gong Y, Soriano D, Patel AP, Perez-Amador MA, Stepanova AN, Alonso JM. An Improved Recombineering Toolset for Plants. THE PLANT CELL 2020; 32:100-122. [PMID: 31666295 PMCID: PMC6961616 DOI: 10.1105/tpc.19.00431] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/07/2019] [Accepted: 10/29/2019] [Indexed: 05/08/2023]
Abstract
Gene functional studies often rely on the expression of a gene of interest as transcriptional and translational fusions with specialized tags. Ideally, this is done in the native chromosomal contexts to avoid potential misexpression artifacts. Although recent improvements in genome editing have made it possible to directly modify the target genes in their native chromosomal locations, classical transgenesis is still the preferred experimental approach chosen in most gene tagging studies because of its time efficiency and accessibility. We have developed a recombineering-based tagging system that brings together the convenience of the classical transgenic approaches and the high degree of confidence in the results obtained by direct chromosomal tagging using genome-editing strategies. These simple, scalable, customizable recombineering toolsets and protocols allow a variety of genetic modifications to be generated. In addition, we developed a highly efficient recombinase-mediated cassette exchange system to facilitate the transfer of the desired sequences from a bacterial artificial chromosome clone to a transformation-compatible binary vector, expanding the use of the recombineering approaches beyond Arabidopsis (Arabidopsis thaliana). We demonstrated the utility of this system by generating more than 250 whole-gene translational fusions and 123 Arabidopsis transgenic lines corresponding to 62 auxin-related genes and characterizing the translational reporter expression patterns for 14 auxin biosynthesis genes.
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Affiliation(s)
- Javier Brumos
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Chengsong Zhao
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Yan Gong
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
- Department of Biology, Stanford University, Stanford, California 94305
| | - David Soriano
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708
| | - Arjun P Patel
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Miguel A Perez-Amador
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), 46022 Valencia, Spain
| | - Anna N Stepanova
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Jose M Alonso
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
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30
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Serrano-Saiz E, Vogt MC, Levy S, Wang Y, Kaczmarczyk KK, Mei X, Bai G, Singson A, Grant BD, Hobert O. SLC17A6/7/8 Vesicular Glutamate Transporter Homologs in Nematodes. Genetics 2020; 214:163-178. [PMID: 31776169 PMCID: PMC6944403 DOI: 10.1534/genetics.119.302855] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 11/24/2019] [Indexed: 01/04/2023] Open
Abstract
Members of the superfamily of solute carrier (SLC) transmembrane proteins transport diverse substrates across distinct cellular membranes. Three SLC protein families transport distinct neurotransmitters into synaptic vesicles to enable synaptic transmission in the nervous system. Among them is the SLC17A6/7/8 family of vesicular glutamate transporters, which endows specific neuronal cell types with the ability to use glutamate as a neurotransmitter. The genome of the nematode Caenorhabditis elegans encodes three SLC17A6/7/8 family members, one of which, eat-4/VGLUT, has been shown to be involved in glutamatergic neurotransmission. Here, we describe our analysis of the two remaining, previously uncharacterized SLC17A6/7/8 family members, vglu-2 and vglu-3 These two genes directly neighbor one another and are the result of a recent gene duplication event in C. elegans, but not in other Caenorhabditis species. Compared to EAT-4, the VGLU-2 and VGLU-3 protein sequences display a more distant similarity to canonical, vertebrate VGLUT proteins. We tagged both genomic loci with gfp and detected no expression of vglu-3 at any stage of development in any cell type of both C. elegans sexes. In contrast, vglu-2::gfp is dynamically expressed in a restricted set of distinct cell types. Within the nervous system, vglu-2::gfp is exclusively expressed in a single interneuron class, AIA, where it localizes to vesicular structures in the soma, but not along the axon, suggesting that VGLU-2 may not be involved in synaptic transport of glutamate. Nevertheless, vglu-2 mutants are partly defective in the function of the AIA neuron in olfactory behavior. Outside the nervous system, VGLU-2 is expressed in collagen secreting skin cells where VGLU-2 most prominently localizes to early endosomes, and to a lesser degree to apical clathrin-coated pits, the trans-Golgi network, and late endosomes. On early endosomes, VGLU-2 colocalizes most strongly with the recycling promoting factor SNX-1, a retromer component. Loss of vglu-2 affects the permeability of the collagen-containing cuticle of the worm, and based on the function of a vertebrate VGLUT1 protein in osteoclasts, we speculate that vglu-2 may have a role in collagen trafficking in the skin. We conclude that C. elegans SLC17A6/7/8 family members have diverse functions within and outside the nervous system.
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Affiliation(s)
- Esther Serrano-Saiz
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, New York 10027
- Centro de Biologia Molecular Severo Ochoa/Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Merly C Vogt
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, New York 10027
| | - Sagi Levy
- Rockefeller University, New York, New York 10065
| | - Yu Wang
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854
| | - Karolina K Kaczmarczyk
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, New York 10027
| | - Xue Mei
- Waksman Institute, Rutgers University, Piscataway, New Jersey 08854
| | - Ge Bai
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854
| | - Andrew Singson
- Waksman Institute, Rutgers University, Piscataway, New Jersey 08854
- Department of Genetics, Rutgers University, Piscataway, New Jersey 08854
| | - Barth D Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, New York 10027
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31
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Marques F, Saro G, Lia AS, Poole RJ, Falquet L, Glauser DA. Identification of avoidance genes through neural pathway-specific forward optogenetics. PLoS Genet 2019; 15:e1008509. [PMID: 31891575 PMCID: PMC6938339 DOI: 10.1371/journal.pgen.1008509] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/05/2019] [Indexed: 11/19/2022] Open
Abstract
Understanding how the nervous system bridges sensation and behavior requires the elucidation of complex neural and molecular networks. Forward genetic approaches, such as screens conducted in C. elegans, have successfully identified genes required to process natural sensory stimuli. However, functional redundancy within the underlying neural circuits, which are often organized with multiple parallel neural pathways, limits our ability to identify 'neural pathway-specific genes', i.e. genes that are essential for the function of some, but not all of these redundant neural pathways. To overcome this limitation, we developed a 'forward optogenetics' screening strategy in which natural stimuli are initially replaced by the selective optogenetic activation of a specific neural pathway. We used this strategy to address the function of the polymodal FLP nociceptors mediating avoidance of noxious thermal and mechanical stimuli. According to our expectations, we identified both mutations in 'general' avoidance genes that broadly impact avoidance responses to a variety of natural noxious stimuli (unc-4, unc-83, and eat-4) and mutations that produce a narrower impact, more restricted to the FLP pathway (syd-2, unc-14 and unc-68). Through a detailed follow-up analysis, we further showed that the Ryanodine receptor UNC-68 acts cell-autonomously in FLP to adjust heat-evoked calcium signals and aversive behaviors. As a whole, our work (i) reveals the importance of properly regulated ER calcium release for FLP function, (ii) provides new entry points for new nociception research and (iii) demonstrates the utility of our forward optogenetic strategy, which can easily be transposed to analyze other neural pathways.
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Affiliation(s)
- Filipe Marques
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Gabriella Saro
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Andrei-Stefan Lia
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Richard J. Poole
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Laurent Falquet
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Swiss Institute of Bioinformatics, Fribourg, Switzerland
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32
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A universal transportin protein drives stochastic choice of olfactory neurons via specific nuclear import of a sox-2-activating factor. Proc Natl Acad Sci U S A 2019; 116:25137-25146. [PMID: 31767767 DOI: 10.1073/pnas.1908168116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Stochastic neuronal cell fate choice involving notch-independent mechanisms is a poorly understood biological process. The Caenorhabditis elegans AWC olfactory neuron pair asymmetrically differentiates into the default AWCOFF and induced AWCON subtypes in a stochastic manner. Stochastic choice of the AWCON subtype is established using gap junctions and SLO BK potassium channels to repress a calcium-activated protein kinase pathway. However, it is unknown how the potassium channel-repressed calcium signaling is translated into the induction of the AWCON subtype. Here, we identify a detailed working mechanism of how the homeodomain-like transcription factor NSY-7, previously described as a repressor in the maintenance of AWC asymmetry, couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype through the identification of a unique imb-2 (transportin 1) allele. imb-2 loss-of-function mutants are not viable; however, we identify a viable imb-2 allele from an unbiased forward genetic screen that reveals a specific role of imb-2 in AWC olfactory neuron asymmetry. IMB-2 specifically drives nuclear import of NSY-7 within AWC neurons to transactivate the expression of the high mobility group (HMG)-box transcription factor SOX-2 for the specification of the AWCON subtype. This study provides mechanistic insight into how NSY-7 couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype. Our findings also provide structure-function insight into a conserved amino acid residue of transportins in brain development and suggest its dysfunction may lead to human neurological disorders.
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33
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Beets I, Zhang G, Fenk LA, Chen C, Nelson GM, Félix MA, de Bono M. Natural Variation in a Dendritic Scaffold Protein Remodels Experience-Dependent Plasticity by Altering Neuropeptide Expression. Neuron 2019; 105:106-121.e10. [PMID: 31757604 PMCID: PMC6953435 DOI: 10.1016/j.neuron.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 08/18/2019] [Accepted: 09/28/2019] [Indexed: 12/13/2022]
Abstract
The extent to which behavior is shaped by experience varies between individuals. Genetic differences contribute to this variation, but the neural mechanisms are not understood. Here, we dissect natural variation in the behavioral flexibility of two Caenorhabditis elegans wild strains. In one strain, a memory of exposure to 21% O2 suppresses CO2-evoked locomotory arousal; in the other, CO2 evokes arousal regardless of previous O2 experience. We map that variation to a polymorphic dendritic scaffold protein, ARCP-1, expressed in sensory neurons. ARCP-1 binds the Ca2+-dependent phosphodiesterase PDE-1 and co-localizes PDE-1 with molecular sensors for CO2 at dendritic ends. Reducing ARCP-1 or PDE-1 activity promotes CO2 escape by altering neuropeptide expression in the BAG CO2 sensors. Variation in ARCP-1 alters behavioral plasticity in multiple paradigms. Our findings are reminiscent of genetic accommodation, an evolutionary process by which phenotypic flexibility in response to environmental variation is reset by genetic change. Behavioral flexibility varies across Caenorhabditis and C. elegans wild isolates A natural polymorphism in ARCP-1 underpins inter-individual variation in plasticity ARCP-1 is a dendritic scaffold protein localizing cGMP signaling machinery to cilia Disrupting ARCP-1 alters behavioral plasticity by changing neuropeptide expression
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Affiliation(s)
- Isabel Beets
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Gaotian Zhang
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France
| | - Lorenz A Fenk
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Changchun Chen
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Geoffrey M Nelson
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Marie-Anne Félix
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France.
| | - Mario de Bono
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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Activity-Dependent Regulation of the Proapoptotic BH3-Only Gene egl-1 in a Living Neuron Pair in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2019; 9:3703-3714. [PMID: 31519744 PMCID: PMC6829140 DOI: 10.1534/g3.119.400654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The BH3-only family of proteins is key for initiating apoptosis in a variety of contexts, and may also contribute to non-apoptotic cellular processes. Historically, the nematode Caenorhabditis elegans has provided a powerful system for studying and identifying conserved regulators of BH3-only proteins. In C. elegans, the BH3-only protein egl-1 is expressed during development to cell-autonomously trigger most developmental cell deaths. Here we provide evidence that egl-1 is also transcribed after development in the sensory neuron pair URX without inducing apoptosis. We used genetic screening and epistasis analysis to determine that its transcription is regulated in URX by neuronal activity and/or in parallel by orthologs of Protein Kinase G and the Salt-Inducible Kinase family. Because several BH3-only family proteins are also expressed in the adult nervous system of mammals, we suggest that studying egl-1 expression in URX may shed light on mechanisms that regulate conserved family members in higher organisms.
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35
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Kume M, Chiyoda H, Kontani K, Katada T, Fukuyama M. Hedgehog-related genes regulate reactivation of quiescent neural progenitors in Caenorhabditis elegans. Biochem Biophys Res Commun 2019; 520:532-537. [PMID: 31615656 DOI: 10.1016/j.bbrc.2019.10.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 10/03/2019] [Indexed: 11/26/2022]
Abstract
The animal body contains various types of stem and progenitor cells. These undifferentiated cells coordinate the balance between quiescence and proliferation with dynamics of various physiological conditions such as the developmental stage, food availability, and injury. Although regulation of such coordination plays a critical role in maintaining tissue homeostasis, controlling the growth rate and regeneration, much of its mechanism remains elusive. Newly hatched Caenorhabditis elegans larvae possess quiescent stem and progenitor cells in several tissues, and these cells are reactivated by the insulin/insulin-like growth factor (IGF) signaling (IIS) pathway only when sufficient food is supplied. Maintenance of the quiescence of neuronal and mesodermal progenitor cells requires microRNA (miRNA), miR-235, which is upregulated under the starvation. On the other hand, feeding ample food downregulates the miRNA via the activity of the IIS pathway. As miR-235 in the hypodermis can non-autonomously regulate quiescence of neuronal and mesodermal progenitor cells, a cell-cell signaling pathway has been hypothesized to act downstream of the miRNA. Here, we provide evidence that two hedgehog-related (hh-r) genes, grl-5 and grl-7, are targets of miR-235 that promote reactivation of quiescent neuroblasts. These grl genes possess an miR-235 binding site on 3'UTRs of their transcripts, and are upregulated in starved mir-235 mutant larvae. grl-5 and grl-7 promoters can continuously drive the expression of GFP-pest reporter protein in the hypodermis under the fed condition. However, expression of these reporters is strikingly downregulated under the starvation condition after hatching. We found that miR-235 can repress expression of reporter genes via the predicted miR-235 binding sites on the grl-5 and grl-7 3'UTRs. Furthermore, activity of grl-5 and grl-7 genes are required for reactivation of neural progenitor cells in starved mir-235 mutant larvae. These findings suggest that the IIS pathway-miR-235 signaling in the hypodermis non-autonomously regulates quiescence of neural progenitor cells, partly via grl-5 and grl-7.
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Affiliation(s)
- Masahiko Kume
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Hirohisa Chiyoda
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Kenji Kontani
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Toshiaki Katada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Masamitsu Fukuyama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
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36
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Hong RL, Riebesell M, Bumbarger DJ, Cook SJ, Carstensen HR, Sarpolaki T, Cochella L, Castrejon J, Moreno E, Sieriebriennikov B, Hobert O, Sommer RJ. Evolution of neuronal anatomy and circuitry in two highly divergent nematode species. eLife 2019; 8:47155. [PMID: 31526477 PMCID: PMC6748829 DOI: 10.7554/elife.47155] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/12/2019] [Indexed: 11/17/2022] Open
Abstract
The nematodes C. elegans and P. pacificus populate diverse habitats and display distinct patterns of behavior. To understand how their nervous systems have diverged, we undertook a detailed examination of the neuroanatomy of the chemosensory system of P. pacificus. Using independent features such as cell body position, axon projections and lipophilic dye uptake, we have assigned homologies between the amphid neurons, their first-layer interneurons, and several internal receptor neurons of P. pacificus and C. elegans. We found that neuronal number and soma position are highly conserved. However, the morphological elaborations of several amphid cilia are different between them, most notably in the absence of ‘winged’ cilia morphology in P. pacificus. We established a synaptic wiring diagram of amphid sensory neurons and amphid interneurons in P. pacificus and found striking patterns of conservation and divergence in connectivity relative to C. elegans, but very little changes in relative neighborhood of neuronal processes. These findings demonstrate the existence of several constraints in patterning the nervous system and suggest that major substrates for evolutionary novelty lie in the alterations of dendritic structures and synaptic connectivity. Nerve cells, also called neurons, are responsible both for sensing signals from the environment and for determining how organisms react. This means that the unique features of an animal’s nervous system underpin its characteristic behaviors. Comparing the anatomy of the nervous systems in different animals could therefore yield valuable insights into how structural and behavioral differences emerge over time. Behavioral variation often occurs even in similar-looking animals. One example is a group of microscopic worms, called nematodes. Although many nematode species exist, their overall body plans are the same, and the worms of each species contain a fixed number of cells. Despite these apparent similarities, different species of nematodes inhabit a variety of environments and may respond differently to the same signals. The main sensory organs in nematodes are called the amphid sensilla. They are used to detect chemicals, as well as other inputs from the environment such as temperature and pheromones from other nematodes. Although researchers have often speculated that the number of cells in these organs and their arrangement are broadly the same across species, their anatomy had not been studied in detail. Hong, Riebesell et al. compared the detailed structure and genetic features of the sensory systems in two distantly related species of nematode worms, Pristionchus pacificus and Caenorhabditis elegans. These two species behave in different ways, for example, P. pacificus is usually found in association with different species of beetles, while C. elegans is free-living and usually found on rotting fruit. By comparing the two, Hong, Riebesell et al. wanted to determine whether the diverse behaviors observed in the two species could be determined by differences between their sensory systems. Experiments using electron microscopy yielded several thousand high resolution images spanning the entire sensory organ. These images were then used to create detailed reconstructions of the sensory nervous system in each worm species, demonstrating that both species had the same number of sensory nerve cells, allowing one-to-one comparisons between them. Further analysis showed that while the overall structure of the neuronal connections remains the same between the two species, the neurons in P. pacificus made more diverse connections than those in C. elegans. Detailed studies of gene activity also revealed that neurons in each species switched on a slightly different group of genes, possibly indicating that each type of worm processes sensory signals in different ways. These results shed new light on how nervous systems in related species can change over time without any change in neuron count. In the future, a better understanding of these changes could link the evolution of the nervous system to the emergence of different behaviors, in both simple and more complex organisms.
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Affiliation(s)
- Ray L Hong
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany.,Department of Biology, California State University, Northridge, Northridge, United States
| | - Metta Riebesell
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Daniel J Bumbarger
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Steven J Cook
- Department of Biological Sciences, Columbia University, New York, United States
| | - Heather R Carstensen
- Department of Biology, California State University, Northridge, Northridge, United States
| | - Tahmineh Sarpolaki
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jessica Castrejon
- Department of Biology, California State University, Northridge, Northridge, United States
| | - Eduardo Moreno
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Bogdan Sieriebriennikov
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, New York, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
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37
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Kamal M, Moshiri H, Magomedova L, Han D, Nguyen KCQ, Yeo M, Knox J, Bagg R, Won AM, Szlapa K, Yip CM, Cummins CL, Hall DH, Roy PJ. The marginal cells of the Caenorhabditis elegans pharynx scavenge cholesterol and other hydrophobic small molecules. Nat Commun 2019; 10:3938. [PMID: 31477732 PMCID: PMC6718421 DOI: 10.1038/s41467-019-11908-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 08/09/2019] [Indexed: 12/24/2022] Open
Abstract
The nematode Caenorhabditis elegans is a bacterivore filter feeder. Through the contraction of the worm’s pharynx, a bacterial suspension is sucked into the pharynx’s lumen. Excess liquid is then shunted out of the buccal cavity through ancillary channels made by surrounding marginal cells. We find that many worm-bioactive small molecules (a.k.a. wactives) accumulate inside of the marginal cells as crystals or globular spheres. Through screens for mutants that resist the lethality associated with one crystallizing wactive we identify a presumptive sphingomyelin-synthesis pathway that is necessary for crystal and sphere accumulation. We find that expression of sphingomyelin synthase 5 (SMS-5) in the marginal cells is not only sufficient for wactive accumulation but is also important for absorbing exogenous cholesterol, without which C. elegans cannot develop. We conclude that sphingomyelin-rich marginal cells act as a sink to scavenge important nutrients from filtered liquid that might otherwise be shunted back into the environment. The C. elegans nematode worm is a filter-feeder and requires dietary sources of cholesterol. Here, the authors show that the C. elegans pharynx works as a filter to scavenge hydrophobic small molecules from its surrounding liquid environment.
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Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Lilia Magomedova
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - Duhyun Han
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Ken C Q Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - May Yeo
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Amy M Won
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Karolina Szlapa
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Christopher M Yip
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Carolyn L Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - David H Hall
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Peter J Roy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada. .,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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38
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Nance J, Frøkjær-Jensen C. The Caenorhabditis elegans Transgenic Toolbox. Genetics 2019; 212:959-990. [PMID: 31405997 PMCID: PMC6707460 DOI: 10.1534/genetics.119.301506] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/01/2019] [Indexed: 12/30/2022] Open
Abstract
The power of any genetic model organism is derived, in part, from the ease with which gene expression can be manipulated. The short generation time and invariant developmental lineage have made Caenorhabditis elegans very useful for understanding, e.g., developmental programs, basic cell biology, neurobiology, and aging. Over the last decade, the C. elegans transgenic toolbox has expanded considerably, with the addition of a variety of methods to control expression and modify genes with unprecedented resolution. Here, we provide a comprehensive overview of transgenic methods in C. elegans, with an emphasis on recent advances in transposon-mediated transgenesis, CRISPR/Cas9 gene editing, conditional gene and protein inactivation, and bipartite systems for temporal and spatial control of expression.
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Affiliation(s)
- Jeremy Nance
- Helen L. and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York 10016
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal 23955-6900, Saudi Arabia
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39
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Leyva-Díaz E, Hobert O. Transcription factor autoregulation is required for acquisition and maintenance of neuronal identity. Development 2019; 146:146/13/dev177378. [PMID: 31227642 DOI: 10.1242/dev.177378] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/13/2019] [Indexed: 01/02/2023]
Abstract
The expression of transcription factors that initiate the specification of a unique cellular identity in multicellular organisms is often maintained throughout the life of the respective cell type via an autoregulatory mechanism. It is generally assumed that such autoregulation serves to maintain the differentiated state of a cell. To experimentally test this assumption, we used CRISPR/Cas9-mediated genome engineering to delete a transcriptional autoregulatory, cis-acting motif in the che-1 zinc-finger transcription factor locus, a terminal selector required to specify the identity of the ASE neuron pair during embryonic development of the nematode Caenorhabditis elegans. We show that che-1 autoregulation is indeed required to maintain the differentiated state of the ASE neurons but that it is also required to amplify che-1 expression during embryonic development to reach an apparent minimal threshold to initiate the ASE differentiation program. We conclude that transcriptional autoregulation fulfills two intrinsically linked purposes: one in proper initiation, the other in proper maintenance of terminal differentiation programs.This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Eduardo Leyva-Díaz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
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40
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Brandt JP, Rossillo M, Du Z, Ichikawa D, Barnes K, Chen A, Noyes M, Bao Z, Ringstad N. Lineage context switches the function of a C. elegans Pax6 homolog in determining a neuronal fate. Development 2019; 146:dev168153. [PMID: 30890567 PMCID: PMC6503985 DOI: 10.1242/dev.168153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 03/11/2019] [Indexed: 01/26/2023]
Abstract
The sensory nervous system of C. elegans comprises cells with varied molecular and functional characteristics, and is, therefore, a powerful model for understanding mechanisms that generate neuronal diversity. We report here that VAB-3, a C. elegans homolog of the homeodomain-containing protein Pax6, has opposing functions in regulating expression of a specific chemosensory fate. A homeodomain-only short isoform of VAB-3 is expressed in BAG chemosensory neurons, where it promotes gene expression and cell function. In other cells, a long isoform of VAB-3, comprising a Paired homology domain and a homeodomain, represses expression of ETS-5, a transcription factor required for expression of BAG fate. Repression of ets-5 requires the Eyes Absent homolog EYA-1 and the Six-class homeodomain protein CEH-32. We determined sequences that mediate high-affinity binding of ETS-5, VAB-3 and CEH-32. The ets-5 locus is enriched for ETS-5-binding sites but lacks sequences that bind VAB-3 and CEH-32, suggesting that these factors do not directly repress ets-5 expression. We propose that a promoter-selection system together with lineage-specific expression of accessory factors allows VAB-3/Pax6 to either promote or repress expression of specific cell fates in a context-dependent manner. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Julia P Brandt
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Mary Rossillo
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Zhuo Du
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - David Ichikawa
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Kristopher Barnes
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Allison Chen
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Marcus Noyes
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Zhirong Bao
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Niels Ringstad
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
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41
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Gómez MD, Fuster-Almunia C, Ocaña-Cuesta J, Alonso JM, Pérez-Amador MA. RGL2 controls flower development, ovule number and fertility in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 281:82-92. [PMID: 30824064 DOI: 10.1016/j.plantsci.2019.01.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/16/2018] [Accepted: 01/12/2019] [Indexed: 06/09/2023]
Abstract
DELLA proteins are a group of plant specific GRAS proteins of transcriptional regulators that have a key role in gibberellin (GA) signaling. In Arabidopsis, the DELLA family is formed by five members. The complexity of this gene family raises the question on whether single DELLA proteins have specific or overlapping functions in the control of several GA-dependent developmental processes. To better understand the roles played by RGL2, one of the DELLA proteins in Arabidopsis, two transgenic lines that express fusion proteins of Venus-RGL2 and a dominant version of RGL2, YPet-rgl2Δ17, were generated by recombineering strategy using a genomic clone that contained the RGL2 gene. The dominant YPet-rgl2Δ17 protein is not degraded by GAs, and therefore it blocks the RGL2-dependent GA signaling and hence RGL2-dependent development. The RGL2 role in seed germination was further confirmed using these genetic tools, while new functions of RGL2 in plant development were uncovered. RGL2 has a clear function in the regulation of flower development, particularly stamen growth and anther dehiscence, which has a great impact in fertility. Moreover, the increased ovule number in the YPet-rgl2Δ17 line points out the role of RGL2 in the determination of ovule number.
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Affiliation(s)
- María Dolores Gómez
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación, Ed. 8E, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
| | - Clara Fuster-Almunia
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación, Ed. 8E, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
| | - Javier Ocaña-Cuesta
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación, Ed. 8E, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
| | - Jose M Alonso
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Miguel A Pérez-Amador
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación, Ed. 8E, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain.
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42
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Breimann L, Preusser F, Preibisch S. Light-microscopy methods in C. elegans research. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.coisb.2018.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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43
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Plasticity of the Electrical Connectome of C. elegans. Cell 2019; 176:1174-1189.e16. [PMID: 30686580 PMCID: PMC10064801 DOI: 10.1016/j.cell.2018.12.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/12/2018] [Accepted: 12/14/2018] [Indexed: 11/23/2022]
Abstract
The specific patterns and functional properties of electrical synapses of a nervous system are defined by the neuron-specific complement of electrical synapse constituents. We systematically examined the molecular composition of the electrical connectome of the nematode C. elegans through a genome- and nervous-system-wide analysis of the expression patterns of the invertebrate electrical synapse constituents, the innexins. We observe highly complex combinatorial expression patterns throughout the nervous system and found that these patterns change in a strikingly neuron-type-specific manner throughout the nervous system when animals enter an insulin-controlled diapause arrest stage under harsh environmental conditions, the dauer stage. By analyzing several individual synapses, we demonstrate that dauer-specific electrical synapse remodeling is responsible for specific aspects of the altered locomotory and chemosensory behavior of dauers. We describe an intersectional gene regulatory mechanism involving terminal selector and FoxO transcription factors mediating dynamic innexin expression plasticity in a neuron-type- and environment-specific manner.
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44
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The transmembrane collagen COL-99 guides longitudinally extending axons in C. elegans. Mol Cell Neurosci 2018; 89:9-19. [DOI: 10.1016/j.mcn.2018.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 03/09/2018] [Indexed: 11/23/2022] Open
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45
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Nazarko O, Kibrom A, Winkler J, Leon K, Stoveken H, Salzman G, Merdas K, Lu Y, Narkhede P, Tall G, Prömel S, Araç D. A Comprehensive Mutagenesis Screen of the Adhesion GPCR Latrophilin-1/ADGRL1. iScience 2018; 3:264-278. [PMID: 30428326 PMCID: PMC6137404 DOI: 10.1016/j.isci.2018.04.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/16/2018] [Accepted: 04/24/2018] [Indexed: 11/15/2022] Open
Abstract
Adhesion G-protein-coupled receptors (aGPCRs) play critical roles in diverse cellular processes in neurobiology, development, immunity, and numerous diseases. The lack of molecular understanding of their activation mechanisms, especially with regard to the transmembrane domains, hampers further studies to facilitate aGPCR-targeted drug development. Latrophilin-1/ADGRL1 is a model aGPCR that regulates synapse formation and embryogenesis, and its mutations are associated with cancer and attention-deficit/hyperactivity disorder. Here, we established functional assays to monitor latrophilin-1 function and showed the activation of latrophilin-1 by its endogenous agonist peptide. Via a comprehensive mutagenesis screen, we identified transmembrane domain residues essential for latrophilin-1 basal activity and for agonist peptide response. Strikingly, a cancer-associated mutation exhibited increased basal activity and failed to rescue the embryonic developmental phenotype in transgenic worms. These results provide a mechanistic foundation for future aGPCR-targeted drug design.
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Affiliation(s)
- Olha Nazarko
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Amanuel Kibrom
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jana Winkler
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Katherine Leon
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Hannah Stoveken
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Gabriel Salzman
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Katarzyna Merdas
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Yue Lu
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Pradnya Narkhede
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Gregory Tall
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Simone Prömel
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Demet Araç
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA.
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46
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Unconventional function of an Achaete-Scute homolog as a terminal selector of nociceptive neuron identity. PLoS Biol 2018; 16:e2004979. [PMID: 29672507 PMCID: PMC5908064 DOI: 10.1371/journal.pbio.2004979] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/12/2018] [Indexed: 11/19/2022] Open
Abstract
Proneural genes are among the most early-acting genes in nervous system development, instructing blast cells to commit to a neuronal fate. Drosophila Atonal and Achaete-Scute complex (AS-C) genes, as well as their vertebrate orthologs, are basic helix-loop-helix (bHLH) transcription factors with such proneural activity. We show here that a C. elegans AS-C homolog, hlh-4, functions in a fundamentally different manner. In the embryonic, larval, and adult nervous systems, hlh-4 is expressed exclusively in a single nociceptive neuron class, ADL, and its expression in ADL is maintained via transcriptional autoregulation throughout the life of the animal. However, in hlh-4 null mutants, the ADL neuron is generated and still appears neuronal in overall morphology and expression of panneuronal and pansensory features. Rather than acting as a proneural gene, we find that hlh-4 is required for the ADL neuron to function properly, to adopt its correct morphology, to express its unusually large repertoire of olfactory receptor-encoding genes, and to express other known features of terminal ADL identity, including neurotransmitter phenotype, neuropeptides, ion channels, and electrical synapse proteins. hlh-4 is sufficient to induce ADL identity features upon ectopic expression in other neuron types. The expression of ADL terminal identity features is directly controlled by HLH-4 via a phylogenetically conserved E-box motif, which, through bioinformatic analysis, we find to constitute a predictive feature of ADL-expressed terminal identity markers. The lineage that produces the ADL neuron was previously shown to require the conventional, transient proneural activity of another AS-C homolog, hlh-14, demonstrating sequential activities of distinct AS-C-type bHLH genes in neuronal specification. Taken together, we have defined here an unconventional function of an AS-C-type bHLH gene as a terminal selector of neuronal identity and we speculate that such function could be reflective of an ancestral function of an "ur-" bHLH gene.
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Alberti C, Manzenreither RA, Sowemimo I, Burkard TR, Wang J, Mahofsky K, Ameres SL, Cochella L. Cell-type specific sequencing of microRNAs from complex animal tissues. Nat Methods 2018; 15:283-289. [PMID: 29481550 PMCID: PMC5886366 DOI: 10.1038/nmeth.4610] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/12/2018] [Indexed: 12/13/2022]
Abstract
MicroRNAs (miRNAs) play an essential role in the post-transcriptional regulation of animal development and physiology. However, in vivo studies aimed at linking miRNA function to the biology of distinct cell types within complex tissues remain challenging, partly because in vivo miRNA-profiling methods lack cellular resolution. We report microRNome by methylation-dependent sequencing (mime-seq), an in vivo enzymatic small-RNA-tagging approach that enables high-throughput sequencing of tissue- and cell-type-specific miRNAs in animals. The method combines cell-type-specific 3'-terminal 2'-O-methylation of animal miRNAs by a genetically encoded, plant-specific methyltransferase (HEN1), with chemoselective small-RNA cloning and high-throughput sequencing. We show that mime-seq uncovers the miRNomes of specific cells within Caenorhabditis elegans and Drosophila at unprecedented specificity and sensitivity, enabling miRNA profiling with single-cell resolution in whole animals. Mime-seq overcomes current challenges in cell-type-specific small-RNA profiling and provides novel entry points for understanding the function of miRNAs in spatially restricted physiological settings.
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Affiliation(s)
- Chiara Alberti
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter Campus (VBC), Vienna, Austria
| | | | - Ivica Sowemimo
- Institute of Molecular Biotechnology (IMBA), Vienna Biocenter Campus (VBC), Vienna, Austria
| | - Thomas R Burkard
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter Campus (VBC), Vienna, Austria.,Institute of Molecular Biotechnology (IMBA), Vienna Biocenter Campus (VBC), Vienna, Austria
| | - Jingkui Wang
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter Campus (VBC), Vienna, Austria
| | - Katharina Mahofsky
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter Campus (VBC), Vienna, Austria
| | - Stefan L Ameres
- Institute of Molecular Biotechnology (IMBA), Vienna Biocenter Campus (VBC), Vienna, Austria
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter Campus (VBC), Vienna, Austria
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48
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Weinberg P, Berkseth M, Zarkower D, Hobert O. Sexually Dimorphic unc-6/Netrin Expression Controls Sex-Specific Maintenance of Synaptic Connectivity. Curr Biol 2018; 28:623-629.e3. [PMID: 29429615 DOI: 10.1016/j.cub.2018.01.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 12/29/2017] [Accepted: 01/01/2018] [Indexed: 12/17/2022]
Abstract
Nervous systems display intriguing patterns of sexual dimorphisms across the animal kingdom, but the mechanisms that generate such dimorphisms remain poorly characterized. In the nematode Caenorhabditis elegans, a number of neurons present in both sexes are synaptically connected to one another in a sexually dimorphic manner as a result of sex-specific synaptic pruning and maintenance [1-3]. We define here a mechanism for the male-specific maintenance of the synaptic connections of the phasmid sensory neuron PHB and its male-specific target, the sex-shared AVG interneuron. We show that the C. elegans Netrin ortholog UNC-6, signaling through its cognate receptor UNC-40/DCC and the CED-5/DOCK180 guanine nucleotide exchange factor, is both required and sufficient for male-specific synaptic maintenance. The dimorphism of unc-6 activity is brought about by sex-specific regulation of unc-6 transcription. Although unc-6 is transcribed in the AVG neuron of males and hermaphrodites during juvenile stages, unc-6 expression is downregulated in AVG in hermaphrodites during sexual maturation but is maintained during sexual maturation of males. unc-6 downregulation in hermaphrodites is conferred by the master regulator of hermaphrodite sexual identity, the Gli/CI homolog TRA-1, which antagonizes the non-sex-specific function of the LIM homeobox gene lin-11, a terminal selector and activator of unc-6 in AVG. Preventing the downregulation of unc-6 in AVG of hermaphrodites through ectopic expression of unc-6 in transgenic animals results in the maintenance of the PHB>AVG synapses in hermaphrodites. Taken together, intersectional transcriptional regulation of unc-6/Netrin is required and sufficient to cell autonomously pattern sexually dimorphic synapses.
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Affiliation(s)
- Peter Weinberg
- Department of Biological Sciences and Howard Hughes Medical Institute, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA
| | - Matthew Berkseth
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - David Zarkower
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - Oliver Hobert
- Department of Biological Sciences and Howard Hughes Medical Institute, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA.
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Antagonistic regulation of trafficking to Caenorhabditis elegans sensory cilia by a Retinal Degeneration 3 homolog and retromer. Proc Natl Acad Sci U S A 2017; 115:E438-E447. [PMID: 29282322 DOI: 10.1073/pnas.1712302115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Sensory neurons often possess cilia with elaborate membrane structures that are adapted to the sensory modality of the host cell. Mechanisms that target sensory transduction proteins to these specialized membrane domains remain poorly understood. Here, we show that a homolog of the human retinal dystrophy gene Retinal Degeneration 3 (RD3) is a Golgi-associated protein required for efficient trafficking of a sensory receptor, the receptor-type guanylate cyclase GCY-9, to cilia in chemosensory neurons of the nematode Caenorhabditis elegans The trafficking defect caused by mutation of the nematode RD3 homolog is suppressed in vivo by mutation of key components of the retromer complex, which mediates recycling of cargo from endosomes to the Golgi. Our data show that there exists a critical balance in sensory neurons between the rates of anterograde and retrograde trafficking of cargo destined for the sensory cilium and this balance requires molecular specialization at an early stage of the secretory pathway.
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50
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Fischer E, Gottschalk A, Schüler C. An optogenetic arrhythmia model to study catecholaminergic polymorphic ventricular tachycardia mutations. Sci Rep 2017; 7:17514. [PMID: 29235522 PMCID: PMC5727474 DOI: 10.1038/s41598-017-17819-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/01/2017] [Indexed: 11/08/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a condition of abnormal heart rhythm (arrhythmia), induced by physical activity or stress. Mutations in ryanodine receptor 2 (RyR2), a Ca2+ release channel located in the sarcoplasmic reticulum (SR), or calsequestrin 2 (CASQ2), a SR Ca2+ binding protein, are linked to CPVT. For specific drug development and to study distinct arrhythmias, simple models are required to implement and analyze such mutations. Here, we introduced CPVT inducing mutations into the pharynx of Caenorhabditis elegans, which we previously established as an optogenetically paced heart model. By electrophysiology and video-microscopy, we characterized mutations in csq-1 (CASQ2 homologue) and unc-68 (RyR2 homologue). csq-1 deletion impaired pharynx function and caused missed pumps during 3.7 Hz pacing. Deletion mutants of unc-68, and in particular the point mutant UNC-68(R4743C), analogous to the established human CPVT mutant RyR2(R4497C), were unable to follow 3.7 Hz pacing, with progressive defects during long stimulus trains. The pharynx either locked in pumping at half the pacing frequency or stopped pumping altogether, possibly due to UNC-68 leakiness and/or malfunctional SR Ca2+ homeostasis. Last, we could reverse this 'worm arrhythmia' by the benzothiazepine S107, establishing the nematode pharynx for studying specific CPVT mutations and for drug screening.
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Affiliation(s)
- Elisabeth Fischer
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany
- University of Edinburgh, Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, EH8 9XE, UK
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany.
- Institute of Biophysical Chemistry, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany.
- Cluster of Excellence Frankfurt - Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany.
| | - Christina Schüler
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany.
- Institute of Biophysical Chemistry, Goethe University, Max von Laue Strasse 15, D-60438, Frankfurt, Germany.
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