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Wang C, Vidal B, Sural S, Loer C, Aguilar GR, Merritt DM, Toker IA, Vogt MC, Cros C, Hobert O. A neurotransmitter atlas of C. elegans males and hermaphrodites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.24.573258. [PMID: 38895397 PMCID: PMC11185579 DOI: 10.1101/2023.12.24.573258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Mapping neurotransmitter identities to neurons is key to understanding information flow in a nervous system. It also provides valuable entry points for studying the development and plasticity of neuronal identity features. In the C. elegans nervous system, neurotransmitter identities have been largely assigned by expression pattern analysis of neurotransmitter pathway genes that encode neurotransmitter biosynthetic enzymes or transporters. However, many of these assignments have relied on multicopy reporter transgenes that may lack relevant cis-regulatory information and therefore may not provide an accurate picture of neurotransmitter usage. We analyzed the expression patterns of 16 CRISPR/Cas9-engineered knock-in reporter strains for all main types of neurotransmitters in C. elegans (glutamate, acetylcholine, GABA, serotonin, dopamine, tyramine, and octopamine) in both the hermaphrodite and the male. Our analysis reveals novel sites of expression of these neurotransmitter systems within both neurons and glia, as well as non-neural cells. The resulting expression atlas defines neurons that may be exclusively neuropeptidergic, substantially expands the repertoire of neurons capable of co-transmitting multiple neurotransmitters, and identifies novel neurons that uptake monoaminergic neurotransmitters. Furthermore, we also observed unusual co-expression patterns of monoaminergic synthesis pathway genes, suggesting the existence of novel monoaminergic transmitters. Our analysis results in what constitutes the most extensive whole-animal-wide map of neurotransmitter usage to date, paving the way for a better understanding of neuronal communication and neuronal identity specification in C. elegans.
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Affiliation(s)
- Chen Wang
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Berta Vidal
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Surojit Sural
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Curtis Loer
- Department of Biology, University of San Diego, San Diego, California, USA
| | - G. Robert Aguilar
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Daniel M. Merritt
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Itai Antoine Toker
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Merly C. Vogt
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Cyril Cros
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, USA
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2
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Tandingan De Ley I, Kiontke K, Bert W, Sudhaus W, Fitch DHA. Pellioditis pelhamensis n. sp. (Nematoda: Rhabditidae) and Pellioditis pellio (Schneider, 1866), earthworm associates from different subclades within Pellioditis (syn. Phasmarhabditis Andrássy, 1976). PLoS One 2023; 18:e0288196. [PMID: 37672545 PMCID: PMC10482300 DOI: 10.1371/journal.pone.0288196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/27/2023] [Indexed: 09/08/2023] Open
Abstract
Recently, much attention has been focused on a group of rhabditid nematodes called Phasmarhabditis, a junior synonym of Pellioditis, as a promising source of biocontrol agents for invasive slugs. Pellioditis pelhamensis n. sp. was first isolated from earthworms near Pelham Bay Park in Bronx, New York, USA, in 1990 and has been found to be pathogenic to slugs as well as some earthworms. It has also been used in several comparative developmental studies. Here, we provide a description of this species, as well as a redescription of a similar earthworm-associated nematode, Pellioditis pellio Schneider, 1866, re-isolated from the type locality. Although P. pelhamensis n. sp. and P. pellio are morphologically similar, they are reproductively isolated. Molecular phylogenetic analysis places both species in a clade that includes all species previously described as Phasmarhabditis which are associated with gastropods. Phasmarhabditis Andrássy, 1976 is therefore a junior synonym of Pellioditis Dougherty, 1953. Also, Pellioditis bohemica Nermut', Půža, Mekete & Mráček, 2017, described to be a facultative parasite of slugs, is found to be a junior synonym of Pellioditis pellio (Schneider, 1866), adding to evidence that P. pellio is associated with both slugs and earthworms. The earthworm-associated species P. pelhamensis n. sp. and P. pellio represent different subclades within Pellioditis, suggesting that Pellioditis species in general have a broader host range than just slugs. Because of this, caution is warranted in using these species as biological control agents until more is understood about their ecology.
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Affiliation(s)
- Irma Tandingan De Ley
- Department of Nematology, University of California, Riverside, CA, United States of America
| | - Karin Kiontke
- Department of Biology, New York University, New York, NY, United States of America
| | - Wim Bert
- Nematology Unit, Department of Biology, Ghent University, Ghent, Belgium
| | - Walter Sudhaus
- Institut für Biologie/Zoologie, Freie Universität Berlin, Berlin, Germany
| | - David H. A. Fitch
- Department of Biology, New York University, New York, NY, United States of America
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3
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Yamamoto KK, Savage-Dunn C. TGF-β pathways in aging and immunity: lessons from Caenorhabditis elegans. Front Genet 2023; 14:1220068. [PMID: 37732316 PMCID: PMC10507863 DOI: 10.3389/fgene.2023.1220068] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/23/2023] [Indexed: 09/22/2023] Open
Abstract
The Transforming Growth Factor-β (TGF-β) superfamily of signaling molecules plays critical roles in development, differentiation, homeostasis, and disease. Due to the conservation of these ligands and their signaling pathways, genetic studies in invertebrate systems including the nematode Caenorhabditis elegans have been instrumental in identifying signaling mechanisms. C. elegans is also a premier organism for research in longevity and healthy aging. Here we summarize current knowledge on the roles of TGF-β signaling in aging and immunity.
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Affiliation(s)
| | - Cathy Savage-Dunn
- Department of Biology, Queens College, and PhD Program in Biology, The Graduate Center, City University of New York, New York City, NY, United States
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4
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Kalis AK, Sterrett MC, Armstrong C, Ballmer A, Burkstrand K, Chilson E, Emlen E, Ferrer E, Loeb S, Olin T, Tran K, Wheeler A, Ross Wolff J. Hox proteins interact to pattern neuronal subtypes in Caenorhabditis elegans males. Genetics 2022; 220:iyac010. [PMID: 35137058 PMCID: PMC8982040 DOI: 10.1093/genetics/iyac010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 01/10/2022] [Indexed: 11/14/2022] Open
Abstract
Hox transcription factors are conserved regulators of neuronal subtype specification on the anteroposterior axis in animals, with disruption of Hox gene expression leading to homeotic transformations of neuronal identities. We have taken advantage of an unusual mutation in the Caenorhabditis elegans Hox gene lin-39, lin-39(ccc16), which transforms neuronal fates in the C. elegans male ventral nerve cord in a manner that depends on a second Hox gene, mab-5. We have performed a genetic analysis centered around this homeotic allele of lin-39 in conjunction with reporters for neuronal target genes and protein interaction assays to explore how LIN-39 and MAB-5 exert both flexibility and specificity in target regulation. We identify cis-regulatory modules in neuronal reporters that are both region-specific and Hox-responsive. Using these reporters of neuronal subtype, we also find that the lin-39(ccc16) mutation disrupts neuronal fates specifically in the region where lin-39 and mab-5 are coexpressed, and that the protein encoded by lin-39(ccc16) is active only in the absence of mab-5. Moreover, the fates of neurons typical to the region of lin-39-mab-5 coexpression depend on both Hox genes. Our genetic analysis, along with evidence from Bimolecular Fluorescence Complementation protein interaction assays, supports a model in which LIN-39 and MAB-5 act at an array of cis-regulatory modules to cooperatively activate and to individually activate or repress neuronal gene expression, resulting in regionally specific neuronal fates.
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Affiliation(s)
- Andrea K Kalis
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Maria C Sterrett
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Cecily Armstrong
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | | | - Kylie Burkstrand
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Elizabeth Chilson
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Estee Emlen
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Emma Ferrer
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Seanna Loeb
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Taylor Olin
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Kevin Tran
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Andrew Wheeler
- Department of Biology, Carleton College, Northfield, MN 55057, USA
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5
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Duerr JS, McManus JR, Crowell JA, Rand JB. Analysis of C. elegans acetylcholine synthesis mutants reveals a temperature-sensitive requirement for cholinergic neuromuscular function. Genetics 2021; 218:6283614. [PMID: 34028515 DOI: 10.1093/genetics/iyab078] [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: 02/01/2021] [Accepted: 05/04/2021] [Indexed: 11/13/2022] Open
Abstract
In Caenorhabditis elegans, the cha-1 gene encodes choline acetyltransferase (ChAT), the enzyme that synthesizes the neurotransmitter acetylcholine. We have analyzed a large number of cha-1 hypomorphic mutants, most of which are missense alleles. Some homozygous cha-1 mutants have approximately normal ChAT immunoreactivity; many other alleles lead to consistent reductions in synaptic immunostaining, although the residual protein appears to be stable. Regardless of protein levels, neuromuscular function of almost all mutants is temperature sensitive, i.e., neuromuscular function is worse at 25° than at 14°. We show that the temperature effects are not related to acetylcholine release, but specifically to alterations in acetylcholine synthesis. This is not a temperature-dependent developmental phenotype, because animals raised at 20° to young adulthood and then shifted for 2 hours to either 14° or 25° had swimming and pharyngeal pumping rates similar to animals grown and assayed at either 14° or 25°, respectively. We also show that the temperature-sensitive phenotypes are not limited to missense alleles; rather, they are a property of most or all severe cha-1 hypomorphs. We suggest that our data are consistent with a model of ChAT protein physically, but not covalently, associated with synaptic vesicles; and there is a temperature-dependent equilibrium between vesicle-associated and cytoplasmic (i.e., soluble) ChAT. Presumably, in severe cha-1 hypomorphs, increasing the temperature would promote dissociation of some of the mutant ChAT protein from synaptic vesicles, thus removing the site of acetylcholine synthesis (ChAT) from the site of vesicular acetylcholine transport. This, in turn, would decrease the rate and extent of vesicle-filling, thus increasing the severity of the behavioral deficits.
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Affiliation(s)
- Janet S Duerr
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Department of Biological Sciences, Ohio University, Athens, Ohio 45701, USA
| | - John R McManus
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - John A Crowell
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - James B Rand
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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6
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Mathews EA, Stroud D, Mullen GP, Gavriilidis G, Duerr JS, Rand JB, Hodgkin J. Allele-specific suppression in C. elegans reveals details of EMS mutagenesis and a possible moonlighting interaction between the vesicular acetylcholine transporter and ERD2 receptors. Genetics 2021; 218:6259149. [PMID: 33914877 PMCID: PMC8664489 DOI: 10.1093/genetics/iyab065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/17/2021] [Indexed: 11/12/2022] Open
Abstract
A missense mutant, unc-17(e245), which affects the Caenorhabditis elegans vesicular acetylcholine transporter UNC-17, has a severe uncoordinated phenotype, allowing efficient selection of dominant suppressors that revert this phenotype to wild-type. Such selections permitted isolation of numerous suppressors after EMS (ethyl methanesulfonate) mutagenesis, leading to demonstration of delays in mutation fixation after initial EMS treatment, as has been shown in T4 bacteriophage but not previously in eukaryotes. Three strong dominant extragenic suppressor loci have been defined, all of which act specifically on allele e245, which causes a G347R mutation in UNC-17. Two of the suppressors (sup-1 and sup-8/snb-1) have previously been shown to encode synaptic proteins able to interact directly with UNC-17. We found that the remaining suppressor, sup-2, corresponds to a mutation in erd-2.1, which encodes an endoplasmic reticulum retention protein; sup-2 causes a V186E missense mutation in transmembrane helix 7 of ERD-2.1. The same missense change introduced into the redundant paralogous gene erd-2.2 also suppressed unc-17(e245). Suppression presumably occurred by compensatory charge interactions between transmembrane helices of UNC-17 and ERD-2.1 or ERD-2.2, as previously proposed in work on suppression by SUP-1(G84E) or SUP-8(I97D)/synaptobrevin. erd-2.1(V186E) homozygotes were fully viable, but erd-2.1(V186E); erd-2.2(RNAi) exhibited synthetic lethality (like erd-2.1(RNAi); erd-2.2(RNAi)), indicating that the missense change in ERD-2.1 impairs its normal function in the secretory pathway but may allow it to adopt a novel moonlighting function as an unc-17 suppressor.
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Affiliation(s)
- Eleanor A Mathews
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Dave Stroud
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Gregory P Mullen
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | | | - Janet S Duerr
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA.,Department of Biological Sciences, Ohio University, Athens, Ohio 45701, USA
| | - James B Rand
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA.,Oklahoma Center for Neuroscience, Oklahoma City, Oklahoma 73104, USA
| | - Jonathan Hodgkin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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7
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Stretton AOW. My life with Sydney, 1961-1971. J Neurogenet 2021; 34:225-237. [PMID: 33446021 DOI: 10.1080/01677063.2020.1834544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
During the 1961-1971 decade, Sydney Brenner made several significant contributions to molecular biology-showing that the genetic code is a triplet code; discovery of messenger RNA; colinearity of gene and protein; decoding of chain terminating codons; and then an important transition: the development of the nematode Caenorhabditis elegans into the model eucaryote genetic system that has permeated the whole of recent biology.
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8
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The Conserved ASCL1/MASH-1 Ortholog HLH-3 Specifies Sex-Specific Ventral Cord Motor Neuron Fate in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2020; 10:4201-4213. [PMID: 32973001 PMCID: PMC7642948 DOI: 10.1534/g3.120.401458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neural specification is regulated by one or many transcription factors that control expression of effector genes that mediate function and determine neuronal type. Here we identify a novel role for one conserved proneural factor, the bHLH protein HLH-3, implicated in the specification of sex-specific ventral cord motor neurons in C. elegans. Proneural genes act in early stages of neurogenesis in early progenitors, but here, we demonstrate a later role for hlh-3. First, we document that differentiation of the ventral cord type C motor neuron class (VC) within their neuron class, is dynamic in time and space. Expression of VC class-specific and subclass-specific identity genes is distinct through development and is dependent on the VC position along the A-P axis and their proximity to the vulva. Our characterization of the expression of VC class and VC subclass-specific differentiation markers in the absence of hlh-3 function reveals that VC fate specification, differentiation, and morphology requires hlh-3 function. Finally, we conclude that hlh-3 cell-autonomously specifies VC cell fate.
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9
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Treinin M, Jin Y. Cholinergic transmission in C. elegans: Functions, diversity, and maturation of ACh-activated ion channels. J Neurochem 2020; 158:1274-1291. [PMID: 32869293 DOI: 10.1111/jnc.15164] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023]
Abstract
Acetylcholine is an abundant neurotransmitter in all animals. Effects of acetylcholine are excitatory, inhibitory, or modulatory depending on the receptor and cell type. Research using the nematode C. elegans has made ground-breaking contributions to the mechanistic understanding of cholinergic transmission. Powerful genetic screens for behavioral mutants or for responses to pharmacological reagents identified the core cellular machinery for synaptic transmission. Pharmacological reagents that perturb acetylcholine-mediated processes led to the discovery and also uncovered the composition and regulators of acetylcholine-activated channels and receptors. From a combination of electrophysiological and molecular cellular studies, we have gained a profound understanding of cholinergic signaling at the levels of synapses, neural circuits, and animal behaviors. This review will begin with a historical overview, then cover in-depth current knowledge on acetylcholine-activated ionotropic receptors, mechanisms regulating their functional expression and their functions in regulating locomotion.
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Affiliation(s)
- Millet Treinin
- Department of Medical Neurobiology, Hadassah Medical school - Hebrew University, Jerusalem, Israel
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
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10
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Modzelewska K, Brown L, Culotti J, Moghal N. Sensory regulated Wnt production from neurons helps make organ development robust to environmental changes in C. elegans. Development 2020; 147:dev186080. [PMID: 32586974 DOI: 10.1242/dev.186080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 06/13/2020] [Indexed: 11/20/2022]
Abstract
Long-term survival of an animal species depends on development being robust to environmental variations and climate changes. We used C. elegans to study how mechanisms that sense environmental changes trigger adaptive responses that ensure animals develop properly. In water, the nervous system induces an adaptive response that reinforces vulval development through an unknown backup signal for vulval induction. This response involves the heterotrimeric G-protein EGL-30//Gαq acting in motor neurons. It also requires body-wall muscle, which is excited by EGL-30-stimulated synaptic transmission, suggesting a behavioral function of neurons induces backup signal production from muscle. We now report that increased acetylcholine during liquid growth activates an EGL-30-Rho pathway, distinct from the synaptic transmission pathway, that increases Wnt production from motor neurons. We also provide evidence that this neuronal Wnt contributes to EGL-30-stimulated vulval development, with muscle producing a parallel developmental signal. As diverse sensory modalities stimulate motor neurons via acetylcholine, this mechanism enables broad sensory perception to enhance Wnt-dependent development. Thus, sensory perception improves animal fitness by activating distinct neuronal functions that trigger adaptive changes in both behavior and developmental processes.
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Affiliation(s)
- Katarzyna Modzelewska
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Louise Brown
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Joseph Culotti
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Nadeem Moghal
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario, M5G 1L7, Canada
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11
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Wani KA, Goswamy D, Irazoqui JE. Nervous system control of intestinal host defense in C. elegans. Curr Opin Neurobiol 2019; 62:1-9. [PMID: 31790812 DOI: 10.1016/j.conb.2019.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/01/2019] [Indexed: 12/16/2022]
Abstract
Interplay between the nervous and immune systems is critical for homeostasis, and its dysfunction underlies pathologies such as multiple sclerosis, autism, leukemia, and inflammation. The nematode Caenorhabditis elegans provides an opportunity to define evolutionarily conserved mechanisms of regulation of host innate immunity and inflammation in a genetically tractable whole-animal system. In the past few years, the C. elegans nervous system has emerged as an integral part of host defense against pathogens, acting through diverse mechanisms to repress or induce protective transcriptional responses to infection in distal tissues. In this review, we discuss current knowledge of the mechanisms through which the C. elegans nervous system controls the expression of host defense genes in the intestinal epithelium. Although still incomplete, the insights derived from such work have broad implications for neural regulation of epithelial function at mucosal barriers in higher organisms in health and disease.
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Affiliation(s)
- Khursheed A Wani
- Department of Microbiology and Physiological Systems and Program in Innate Immunity, University of Massachusetts Medical School, Worcester, USA
| | - Debanjan Goswamy
- Department of Microbiology and Physiological Systems and Program in Innate Immunity, University of Massachusetts Medical School, Worcester, USA
| | - Javier E Irazoqui
- Department of Microbiology and Physiological Systems and Program in Innate Immunity, University of Massachusetts Medical School, Worcester, USA.
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12
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Labed SA, Wani KA, Jagadeesan S, Hakkim A, Najibi M, Irazoqui JE. Intestinal Epithelial Wnt Signaling Mediates Acetylcholine-Triggered Host Defense against Infection. Immunity 2019; 48:963-978.e3. [PMID: 29768179 DOI: 10.1016/j.immuni.2018.04.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 02/02/2018] [Accepted: 04/17/2018] [Indexed: 12/21/2022]
Abstract
Regulated antimicrobial peptide expression in the intestinal epithelium is key to defense against infection and to microbiota homeostasis. Understanding the mechanisms that regulate such expression is necessary for understanding immune homeostasis and inflammatory disease and for developing safe and effective therapies. We used Caenorhabditis elegans in a preclinical approach to discover mechanisms of antimicrobial gene expression control in the intestinal epithelium. We found an unexpected role for the cholinergic nervous system. Infection-induced acetylcholine release from neurons stimulated muscarinic signaling in the epithelium, driving downstream induction of Wnt expression in the same tissue. Wnt induction activated the epithelial canonical Wnt pathway, resulting in the expression of C-type lectin and lysozyme genes that enhanced host defense. Furthermore, the muscarinic and Wnt pathways are linked by conserved transcription factors. These results reveal a tight connection between the nervous system and the intestinal epithelium, with important implications for host defense, immune homeostasis, and cancer.
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Affiliation(s)
- Sid Ahmed Labed
- Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA 02114, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Khursheed A Wani
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sakthimala Jagadeesan
- Department of Molecular Biology, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA 02114, USA
| | - Abdul Hakkim
- Department of Molecular Biology, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA 02114, USA
| | - Mehran Najibi
- Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA 02114, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Javier Elbio Irazoqui
- Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA 02114, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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13
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Pan JP, Hu Y, Wang JH, Xin YR, Jiang JX, Chen KQ, Yang CY, Gao Q, Xiao F, Yan L, Luo HM. Methyl 3,4-Dihydroxybenzoate Induces Neural Stem Cells to Differentiate Into Cholinergic Neurons in vitro. Front Cell Neurosci 2018; 12:478. [PMID: 30581378 PMCID: PMC6292956 DOI: 10.3389/fncel.2018.00478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 11/22/2018] [Indexed: 01/08/2023] Open
Abstract
Neural stem cells (NSCs) have been shown as a potential source for replacing degenerated neurons in neurodegenerative diseases. However, the therapeutic potential of these cells is limited by the lack of effective methodologies for controlling their differentiation. Inducing endogenous pools of NSCs by small molecule can be considered as a potential approach of generating the desired cell types in large numbers. Here, we reported the characterization of a small molecule (Methyl 3,4-dihydroxybenzoate; MDHB) that selectively induces hippocampal NSCs to differentiate into cholinergic motor neurons which expressed synapsin 1 (SYN1) and postsynaptic density protein 95 (PSD-95). Studies on the mechanisms revealed that MDHB induced the hippocampal NSCs differentiation into cholinergic motor neurons by inhibiting AKT phosphorylation and activating autophosphorylation of GSK3β at tyrosine 216. Furthermore, we found that MDHB enhanced β-catenin degradation and abolished its entering into the nucleus. Collectively, this report provides the strong evidence that MDHB promotes NSCs differentiation into cholinergic motor neurons by enhancing gene Isl1 expression and inhibiting cell cycle progression. It may provide a basis for pharmacological effects of MDHB directed on NSCs.
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Affiliation(s)
- Jun-Ping Pan
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China.,Department of Neurosurgery, Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Yang Hu
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China.,Institute of Brain Sciences, Jinan University, Guangzhou, China
| | - Jia-Hui Wang
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China
| | - Yi-Rong Xin
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China
| | - Jun-Xing Jiang
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China
| | - Ke-Qi Chen
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China
| | - Cheng-You Yang
- Department of Neurosurgery, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Qin Gao
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China
| | - Fei Xiao
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China.,Institute of Brain Sciences, Jinan University, Guangzhou, China
| | - Li Yan
- Guangzhou Quality R&D Center of Traditional Chinese Medicine, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huan-Min Luo
- Department of Pharmacology, College of Basic Medicine, Jinan University, Guangzhou, China.,Institute of Brain Sciences, Jinan University, Guangzhou, China
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14
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Wen Q, Gao S, Zhen M. Caenorhabditis elegans excitatory ventral cord motor neurons derive rhythm for body undulation. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0370. [PMID: 30201835 DOI: 10.1098/rstb.2017.0370] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2018] [Indexed: 12/25/2022] Open
Abstract
The intrinsic oscillatory activity of central pattern generators underlies motor rhythm. We review and discuss recent findings that address the origin of Caenorhabditis elegans motor rhythm. These studies propose that the A- and mid-body B-class excitatory motor neurons at the ventral cord function as non-bursting intrinsic oscillators to underlie body undulation during reversal and forward movements, respectively. Proprioception entrains their intrinsic activities, allows phase-coupling between members of the same class motor neurons, and thereby facilitates directional propagation of undulations. Distinct pools of premotor interneurons project along the ventral nerve cord to innervate all members of the A- and B-class motor neurons, modulating their oscillations, as well as promoting their bi-directional coupling. The two motor sub-circuits, which consist of oscillators and descending inputs with distinct properties, form the structural base of dynamic rhythmicity and flexible partition of the forward and backward motor states. These results contribute to a continuous effort to establish a mechanistic and dynamic model of the C. elegans sensorimotor system. C. elegans exhibits rich sensorimotor functions despite a small neuron number. These findings implicate a circuit-level functional compression. By integrating the role of rhythm generation and proprioception into motor neurons, and the role of descending regulation of oscillators into premotor interneurons, this numerically simple nervous system can achieve a circuit infrastructure analogous to that of anatomically complex systems. C. elegans has manifested itself as a compact model to search for general principles of sensorimotor behaviours.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.
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Affiliation(s)
- Quan Wen
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, People's Republic of China .,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Mei Zhen
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital; Department of Molecular Genetics, Department of Physiology, University of Toronto, Toronto, Ontario M5G 1XS, Canada
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15
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A sensory-motor neuron type mediates proprioceptive coordination of steering in C. elegans via two TRPC channels. PLoS Biol 2018; 16:e2004929. [PMID: 29883446 PMCID: PMC6010301 DOI: 10.1371/journal.pbio.2004929] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 06/20/2018] [Accepted: 05/24/2018] [Indexed: 11/25/2022] Open
Abstract
Animal locomotion is mediated by a sensory system referred to as proprioception. Defects in the proprioceptive coordination of locomotion result in uncontrolled and inefficient movements. However, the molecular mechanisms underlying proprioception are not fully understood. Here, we identify two transient receptor potential cation (TRPC) channels, trp-1 and trp-2, as necessary and sufficient for proprioceptive responses in C. elegans head steering locomotion. Both channels are expressed in the SMDD neurons, which are required and sufficient for head bending, and mediate coordinated head steering by sensing mechanical stretches due to the contraction of head muscle and orchestrating dorsal head muscle contractions. Moreover, the SMDD neurons play dual roles to sense muscle stretch as well as to control muscle contractions. These results demonstrate that distinct locomotion patterns require dynamic and homeostatic modulation of feedback signals between neurons and muscles. Proprioception provides the nervous system with feedback about body posture in animals and is essential for the generation of coherent locomotive behaviors, such as walking, running, or crawling. However, little is known about the identity of proprioceptive receptors that sense body movement to regulate locomotion and the extent to which proprioception modulates sensorimotor coordination. Here, we analyze the molecular mechanisms that control head steering locomotion of Caenorhabditis elegans. We show that this movement is regulated by the transient receptor potential cation (TRPC) channels TRP-1 and TRP-2 and the SMDD proprioceptive neurons. We observe that mutant animals for both channels are defective in head steering locomotion and that ectopic expression of TRP-1 or TPR-2 in a C. elegans chemosensory neuron confers head bending–dependent responses, suggesting roles for these channels in proprioception. We also find that SMDD neurons are both necessary and sufficient to generate head steering locomotion via the two channels. Moreover, we demonstrate that the proprioceptive system mediates locomotion coordination by desynchronizing activities in motor systems. We conclude that two TRPC channels in collaboration with the proprioceptive receptor SMDD neurons control head steering in worms during forward locomotion.
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16
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Regulation of Glutamate Signaling in the Sensorimotor Circuit by CASY-1A/Calsyntenin in Caenorhabditis elegans. Genetics 2018; 208:1553-1564. [PMID: 29475851 PMCID: PMC5887148 DOI: 10.1534/genetics.118.300834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 02/21/2018] [Indexed: 12/02/2022] Open
Abstract
Locomotion is one of the most prominent behaviors in the nematode Caenorhabditis elegans. Neuronal circuits that ultimately produce coordinated dorso-ventral sinusoidal bends mediate this behavior. Synchronized locomotion requires an intricate balance between excitation and inhibition at the neuromuscular junctions (NMJ), the complex cellular and molecular mechanisms of which are not fully understood. Here, we describe the role of a cell adhesion molecule CASY-1, which functions to maintain this balance at the NMJ. In this study, we dissect out mechanisms by which the longer CASY-1A isoform could be affecting the excitatory cholinergic signaling at the NMJ by modulating the activity of sensory neurons. Mutants in casy-1 appear to have hyperactive sensory neurons, resulting in accelerated locomotion and motor circuit activity. These sensory neurons mediate increased motor activity via enhanced glutamate release. Using genetic, pharmacological, and optogenetic manipulations, we establish that CASY-1A is required to monitor the activity of these neurons. Our study illustrates a novel neuromodulatory role of CASY-1-mediated signaling in regulating the excitation-inhibition balance of the motor circuit.
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17
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Gao S, Guan SA, Fouad AD, Meng J, Kawano T, Huang YC, Li Y, Alcaire S, Hung W, Lu Y, Qi YB, Jin Y, Alkema M, Fang-Yen C, Zhen M. Excitatory motor neurons are local oscillators for backward locomotion. eLife 2018; 7:e29915. [PMID: 29360035 PMCID: PMC5780044 DOI: 10.7554/elife.29915] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/22/2017] [Indexed: 01/16/2023] Open
Abstract
Cell- or network-driven oscillators underlie motor rhythmicity. The identity of C. elegans oscillators remains unknown. Through cell ablation, electrophysiology, and calcium imaging, we show: (1) forward and backward locomotion is driven by different oscillators; (2) the cholinergic and excitatory A-class motor neurons exhibit intrinsic and oscillatory activity that is sufficient to drive backward locomotion in the absence of premotor interneurons; (3) the UNC-2 P/Q/N high-voltage-activated calcium current underlies A motor neuron's oscillation; (4) descending premotor interneurons AVA, via an evolutionarily conserved, mixed gap junction and chemical synapse configuration, exert state-dependent inhibition and potentiation of A motor neuron's intrinsic activity to regulate backward locomotion. Thus, motor neurons themselves derive rhythms, which are dually regulated by the descending interneurons to control the reversal motor state. These and previous findings exemplify compression: essential circuit properties are conserved but executed by fewer numbers and layers of neurons in a small locomotor network.
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Affiliation(s)
- Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and Technology, Huazhong University of Science and TechnologyWuhanChina
| | - Sihui Asuka Guan
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Anthony D Fouad
- Department of BioengineeringSchool of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Jun Meng
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Taizo Kawano
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Yung-Chi Huang
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Yi Li
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and Technology, Huazhong University of Science and TechnologyWuhanChina
| | - Salvador Alcaire
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Wesley Hung
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Yangning Lu
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Yingchuan Billy Qi
- Neurobiology Section, Division of Biological SciencesUniversity of CaliforniaSan DiegoUnited States
| | - Yishi Jin
- Neurobiology Section, Division of Biological SciencesUniversity of CaliforniaSan DiegoUnited States
| | - Mark Alkema
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Christopher Fang-Yen
- Department of BioengineeringSchool of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
- Department of NeuroscienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
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18
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Fouad AD, Teng S, Mark JR, Liu A, Alvarez-Illera P, Ji H, Du A, Bhirgoo PD, Cornblath E, Guan SA, Fang-Yen C. Distributed rhythm generators underlie Caenorhabditis elegans forward locomotion. eLife 2018; 7:e29913. [PMID: 29360037 PMCID: PMC5780042 DOI: 10.7554/elife.29913] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022] Open
Abstract
Coordinated rhythmic movements are ubiquitous in animal behavior. In many organisms, chains of neural oscillators underlie the generation of these rhythms. In C. elegans, locomotor wave generation has been poorly understood; in particular, it is unclear where in the circuit rhythms are generated, and whether there exists more than one such generator. We used optogenetic and ablation experiments to probe the nature of rhythm generation in the locomotor circuit. We found that multiple sections of forward locomotor circuitry are capable of independently generating rhythms. By perturbing different components of the motor circuit, we localize the source of secondary rhythms to cholinergic motor neurons in the midbody. Using rhythmic optogenetic perturbation, we demonstrate bidirectional entrainment of oscillations between different body regions. These results show that, as in many other vertebrates and invertebrates, the C. elegans motor circuit contains multiple oscillators that coordinate activity to generate behavior.
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Affiliation(s)
- Anthony D Fouad
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Shelly Teng
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Julian R Mark
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Alice Liu
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Pilar Alvarez-Illera
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Hongfei Ji
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Angelica Du
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Priya D Bhirgoo
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Eli Cornblath
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Sihui Asuka Guan
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied ScienceUniversity of PennsylvaniaPhiladelphiaUnited States
- Department of Neuroscience, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaUnited States
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19
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Diversification of C. elegans Motor Neuron Identity via Selective Effector Gene Repression. Neuron 2017; 93:80-98. [PMID: 28056346 DOI: 10.1016/j.neuron.2016.11.036] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/11/2016] [Accepted: 11/11/2016] [Indexed: 12/20/2022]
Abstract
A common organizational feature of nervous systems is the existence of groups of neurons that share common traits but can be divided into individual subtypes based on anatomical or molecular features. We elucidate the mechanistic basis of neuronal diversification processes in the context of C.elegans ventral cord motor neurons that share common traits that are directly activated by the terminal selector UNC-3. Diversification of motor neurons into different classes, each characterized by unique patterns of effector gene expression, is controlled by distinct combinations of phylogenetically conserved, class-specific transcriptional repressors. These repressors are continuously required in postmitotic neurons to prevent UNC-3, which is active in all neuron classes, from activating class-specific effector genes in specific motor neuron subsets via discrete cis-regulatory elements. The strategy of antagonizing the activity of broadly acting terminal selectors of neuron identity in a subtype-specific fashion may constitute a general principle of neuron subtype diversification.
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20
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Serrano-Saiz E, Pereira L, Gendrel M, Aghayeva U, Bhattacharya A, Howell K, Garcia LR, Hobert O. A Neurotransmitter Atlas of the Caenorhabditis elegans Male Nervous System Reveals Sexually Dimorphic Neurotransmitter Usage. Genetics 2017; 206:1251-1269. [PMID: 28684604 PMCID: PMC5500128 DOI: 10.1534/genetics.117.202127] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/03/2017] [Indexed: 11/18/2022] Open
Abstract
The nervous system of most animals is sexually dimorphic but such dimorphisms are generally poorly mapped on an anatomical, cellular, and molecular level. The adult nervous system of the nematode Caenorhabditis elegans displays a number of clearly defined anatomical sexual dimorphisms, but molecular features of sexually dimorphic neurons remain sparse. In this resource paper, we provide a comprehensive atlas of neurotransmitters used in the nervous system of the male and compare it to that of the hermaphrodite. Among the three major neurotransmitter systems, acetylcholine (ACh) is the most frequently used, followed by glutamate (Glu), and lastly γ-aminobutyric acid (GABA). Many male-specific neurons utilize multiple neurotransmitter systems. Interestingly, we find that neurons that are present in both sexes alter their neurotransmitter usage depending on the sex of the animal. One neuron scales up its usage of ACh, another becomes serotonergic in males, and another one adds a new neurotransmitter (glutamate) to its nonsex-specific transmitter (ACh). In all these cases, neurotransmitter changes are correlated with substantial changes in synaptic connectivity. We assembled the neurotransmitter maps of the male-specific nervous system into a comprehensive atlas that describes the anatomical position of all the neurons of the male-specific nervous system relative to the sex-shared nervous system. We exemplify the usefulness of the neurotransmitter atlas by using it as a tool to define the expression pattern of a synaptic organizer molecule in the male tail. Taken together, the male neurotransmitter atlas provides an entry point for future functional and developmental analysis of the male nervous system.
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Affiliation(s)
- Esther Serrano-Saiz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
| | - Laura Pereira
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
| | - Marie Gendrel
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
| | - Ulkar Aghayeva
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
| | - Abhishek Bhattacharya
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
| | - Kelly Howell
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
| | - L Rene Garcia
- Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York 10027
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21
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Minnerly J, Zhang J, Parker T, Kaul T, Jia K. The cell non-autonomous function of ATG-18 is essential for neuroendocrine regulation of Caenorhabditis elegans lifespan. PLoS Genet 2017; 13:e1006764. [PMID: 28557996 PMCID: PMC5469504 DOI: 10.1371/journal.pgen.1006764] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 06/13/2017] [Accepted: 04/18/2017] [Indexed: 12/11/2022] Open
Abstract
Dietary restriction (DR) and reduced insulin growth factor (IGF) signaling extend lifespan in Caenorhabditis elegans and other eukaryotic organisms. Autophagy, an evolutionarily conserved lysosomal degradation pathway, has emerged as a central pathway regulated by various longevity signals including DR and IGF signaling in promoting longevity in a variety of eukaryotic organisms. However, the mechanism remains unclear. Here we show that the autophagy protein ATG-18 acts cell non-autonomously in neuronal and intestinal tissues to maintain C. elegans wildtype lifespan and to respond to DR and IGF-mediated longevity signaling. Moreover, ATG-18 activity in chemosensory neurons that are involved in food detection sufficiently mediates the effect of these longevity pathways. Additionally, ATG-18-mediated cell non-autonomous signaling depends on the release of neurotransmitters and neuropeptides. Interestingly, our data suggest that neuronal and intestinal ATG-18 acts in parallel and converges on unidentified neurons that secrete neuropeptides to regulate C. elegans lifespan through the transcription factor DAF-16/FOXO in response to reduced IGF signaling.
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Affiliation(s)
- Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Jiuli Zhang
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Thomas Parker
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Tiffany Kaul
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
- * E-mail:
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22
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Liu P, Chen B, Mailler R, Wang ZW. Antidromic-rectifying gap junctions amplify chemical transmission at functionally mixed electrical-chemical synapses. Nat Commun 2017; 8:14818. [PMID: 28317880 PMCID: PMC5364397 DOI: 10.1038/ncomms14818] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 02/06/2017] [Indexed: 11/09/2022] Open
Abstract
Neurons communicate through chemical synapses and electrical synapses (gap junctions). Although these two types of synapses often coexist between neurons, little is known about whether they interact, and whether any interactions between them are important to controlling synaptic strength and circuit functions. By studying chemical and electrical synapses between premotor interneurons (AVA) and downstream motor neurons (A-MNs) in the Caenorhabditis elegans escape circuit, we found that disrupting either the chemical or electrical synapses causes defective escape response. Gap junctions between AVA and A-MNs only allow antidromic current, but, curiously, disrupting them inhibits chemical transmission. In contrast, disrupting chemical synapses has no effect on the electrical coupling. These results demonstrate that gap junctions may serve as an amplifier of chemical transmission between neurons with both electrical and chemical synapses. The use of antidromic-rectifying gap junctions to amplify chemical transmission is potentially a conserved mechanism in circuit functions.
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Affiliation(s)
- Ping Liu
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Bojun Chen
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Roger Mailler
- Department of Computer Science, University of Tulsa, Tulsa, Oklahoma 74104, USA
| | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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23
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Schwarz J, Bringmann H. Analysis of the NK2 homeobox gene ceh-24 reveals sublateral motor neuron control of left-right turning during sleep. eLife 2017; 6. [PMID: 28244369 PMCID: PMC5384828 DOI: 10.7554/elife.24846] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 02/26/2017] [Indexed: 11/30/2022] Open
Abstract
Sleep is a behavior that is found in all animals that have a nervous system and that have been studied carefully. In Caenorhabditis elegans larvae, sleep is associated with a turning behavior, called flipping, in which animals rotate 180° about their longitudinal axis. However, the molecular and neural substrates of this enigmatic behavior are not known. Here, we identified the conserved NK-2 homeobox gene ceh-24 to be crucially required for flipping. ceh-24 is required for the formation of processes and for cholinergic function of sublateral motor neurons, which separately innervate the four body muscle quadrants. Knockdown of cholinergic function in a subset of these sublateral neurons, the SIAs, abolishes flipping. The SIAs depolarize during flipping and their optogenetic activation induces flipping in a fraction of events. Thus, we identified the sublateral SIA neurons to control the three-dimensional movements of flipping. These neurons may also control other types of motion. DOI:http://dx.doi.org/10.7554/eLife.24846.001 Although sleeping individuals do not move voluntarily, they are not completely immobile. Both people and animals regularly change position in their sleep, but it is not known why these movements occur or what regulates them. One of the simplest animals known to require sleep is the nematode worm Caenorhabditis elegans, which is often used by researchers to study the molecular basis of behavior. In common with more complex animals, worms go to sleep lying on either their left or right side and then switch periodically between the two. This “flipping” behavior is typically not seen outside of sleep. By screening worms with mutations in different genes, Schwarz and Bringmann identified one mutant that does not flip during sleep. The mutant lacked a gene called ceh-24, which is normally active in a set of four neurons known as SIAs. These are a type of motor neuron; that is, neurons that control the contraction of muscles. The body wall muscles of C. elegans run along the length of its body and are organized into “quadrants” that each cover a quarter of the worm. Schwarz and Bringmann show that unlike other C. elegans motor neurons, SIA neurons control each quadrant separately. By activating specific SIA neurons the worms can contract the muscles on each side of the body independently, and thereby flip from one side to the other. Further investigation revealed that the SIA motor neurons can also control other types of complex movement. Additional experiments are now needed to determine how the neurons support these behaviors. Another challenge will be to work out the purpose of posture changes during sleep for C. elegans and other animals. DOI:http://dx.doi.org/10.7554/eLife.24846.002
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Affiliation(s)
- Juliane Schwarz
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henrik Bringmann
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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24
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Kalinnikova TB, Kolsanova RR, Belova EB, Shagidullin RR, Gainutdinov MK. Opposite effects of moderate heat stress and hyperthermia on cholinergic system of soil nematodes Caenorhabditis elegans and Caenorhabditis briggsae. J Therm Biol 2016; 62:37-49. [PMID: 27839548 DOI: 10.1016/j.jtherbio.2016.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 05/26/2016] [Accepted: 05/29/2016] [Indexed: 10/20/2022]
Abstract
Cholinergic system plays important role in all functions of organisms of free-living soil nematodes C. elegans and C. briggsae. Using pharmacological analysis we showed the existence of two opposite responses of nematodes cholinergic system to moderate and extreme heat stress. Short-term (15min) noxious heat (31-32°C) caused activation of cholinergic synaptic transmission in C. elegans and C. briggsae organisms by sensitization of nicotinic ACh receptors. In contrast, hyperthermia blocked cholinergic synaptic transmission by inhibition of ACh secretion by neurons. The resistance of behavior to extreme high temperature (36-37°C) was significantly higher in C. briggsae than in C. elegans, and thermostability of cholinergic transmission correlated with resistance of behavior to hyperthermia. Activation of cholinergic transmission by moderate heat stress can be the reason of movement speed increase in such adaptive behavior as noxious heat escape. Inhibition of ACh release is one of reasons for behavior failure caused by extreme high temperature since partial inhibition of ACh-esterase by aldicarb protected C. elegans and C. briggsae behavior against hyperthermia. Antagonist of mAChRs atropine almost completely prevented the rise in behavior thermotolerance caused by aldicarb. Pilocarpine, agonist of mAChRs, protected nematodes behavior against hyperthermia similarly with aldicarb. Therefore it is evident that it is the deficiency of mAChRs activity that is the reason for nematodes' behavior failure by hyperthermia.
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Affiliation(s)
- Tatiana B Kalinnikova
- Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia.
| | - Rufina R Kolsanova
- Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia
| | - Evgenia B Belova
- Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia
| | - Rifgat R Shagidullin
- Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia
| | - Marat Kh Gainutdinov
- Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia
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25
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Shen Y, Wen Q, Liu H, Zhong C, Qin Y, Harris G, Kawano T, Wu M, Xu T, Samuel AD, Zhang Y. An extrasynaptic GABAergic signal modulates a pattern of forward movement in Caenorhabditis elegans. eLife 2016; 5:e14197. [PMID: 27138642 DOI: 10.7554/elife.14197.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/04/2016] [Indexed: 05/24/2023] Open
Abstract
As a common neurotransmitter in the nervous system, γ-aminobutyric acid (GABA) modulates locomotory patterns in both vertebrates and invertebrates. However, the signaling mechanisms underlying the behavioral effects of GABAergic modulation are not completely understood. Here, we demonstrate that a GABAergic signal in C. elegans modulates the amplitude of undulatory head bending through extrasynaptic neurotransmission and conserved metabotropic receptors. We show that the GABAergic RME head motor neurons generate undulatory activity patterns that correlate with head bending and the activity of RME causally links with head bending amplitude. The undulatory activity of RME is regulated by a pair of cholinergic head motor neurons SMD, which facilitate head bending, and inhibits SMD to limit head bending. The extrasynaptic neurotransmission between SMD and RME provides a gain control system to set head bending amplitude to a value correlated with optimal efficiency of forward movement.
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Affiliation(s)
- Yu Shen
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Quan Wen
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, United States
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Science and Technology of China, Hefei, China
| | - He Liu
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Connie Zhong
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Yuqi Qin
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Gareth Harris
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Taizo Kawano
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Canada
| | - Min Wu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Tianqi Xu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Aravinthan Dt Samuel
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, United States
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
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26
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Shen Y, Wen Q, Liu H, Zhong C, Qin Y, Harris G, Kawano T, Wu M, Xu T, Samuel AD, Zhang Y. An extrasynaptic GABAergic signal modulates a pattern of forward movement in Caenorhabditis elegans. eLife 2016; 5. [PMID: 27138642 PMCID: PMC4854516 DOI: 10.7554/elife.14197] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/04/2016] [Indexed: 11/13/2022] Open
Abstract
As a common neurotransmitter in the nervous system, γ-aminobutyric acid (GABA) modulates locomotory patterns in both vertebrates and invertebrates. However, the signaling mechanisms underlying the behavioral effects of GABAergic modulation are not completely understood. Here, we demonstrate that a GABAergic signal in C. elegans modulates the amplitude of undulatory head bending through extrasynaptic neurotransmission and conserved metabotropic receptors. We show that the GABAergic RME head motor neurons generate undulatory activity patterns that correlate with head bending and the activity of RME causally links with head bending amplitude. The undulatory activity of RME is regulated by a pair of cholinergic head motor neurons SMD, which facilitate head bending, and inhibits SMD to limit head bending. The extrasynaptic neurotransmission between SMD and RME provides a gain control system to set head bending amplitude to a value correlated with optimal efficiency of forward movement. DOI:http://dx.doi.org/10.7554/eLife.14197.001
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Affiliation(s)
- Yu Shen
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Quan Wen
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China.,Department of Physics, Center for Brain Science, Harvard University, Cambridge, United States.,CAS Center for Excellence in Brain Science and Intelligence Technology, University of Science and Technology of China, Hefei, China
| | - He Liu
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Connie Zhong
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Yuqi Qin
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Gareth Harris
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Taizo Kawano
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Canada
| | - Min Wu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Tianqi Xu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Aravinthan Dt Samuel
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, United States
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
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27
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Wallace SW, Singhvi A, Liang Y, Lu Y, Shaham S. PROS-1/Prospero Is a Major Regulator of the Glia-Specific Secretome Controlling Sensory-Neuron Shape and Function in C. elegans. Cell Rep 2016; 15:550-562. [PMID: 27068465 DOI: 10.1016/j.celrep.2016.03.051] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/25/2016] [Accepted: 03/12/2016] [Indexed: 01/03/2023] Open
Abstract
Sensory neurons are an animal's gateway to the world, and their receptive endings, the sites of sensory signal transduction, are often associated with glia. Although glia are known to promote sensory-neuron functions, the molecular bases of these interactions are poorly explored. Here, we describe a post-developmental glial role for the PROS-1/Prospero/PROX1 homeodomain protein in sensory-neuron function in C. elegans. Using glia expression profiling, we demonstrate that, unlike previously characterized cell fate roles, PROS-1 functions post-embryonically to control sense-organ glia-specific secretome expression. PROS-1 functions cell autonomously to regulate glial secretion and membrane structure, and non-cell autonomously to control the shape and function of the receptive endings of sensory neurons. Known glial genes controlling sensory-neuron function are PROS-1 targets, and we identify additional PROS-1-dependent genes required for neuron attributes. Drosophila Prospero and vertebrate PROX1 are expressed in post-mitotic sense-organ glia and astrocytes, suggesting conserved roles for this class of transcription factors.
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Affiliation(s)
- Sean W Wallace
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Aakanksha Singhvi
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yupu Liang
- CCTS Research Bioinformatics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yun Lu
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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28
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Pereira L, Kratsios P, Serrano-Saiz E, Sheftel H, Mayo AE, Hall DH, White JG, LeBoeuf B, Garcia LR, Alon U, Hobert O. A cellular and regulatory map of the cholinergic nervous system of C. elegans. eLife 2015; 4. [PMID: 26705699 PMCID: PMC4769160 DOI: 10.7554/elife.12432] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 12/22/2015] [Indexed: 12/18/2022] Open
Abstract
Nervous system maps are of critical importance for understanding how nervous systems develop and function. We systematically map here all cholinergic neuron types in the male and hermaphrodite C. elegans nervous system. We find that acetylcholine (ACh) is the most broadly used neurotransmitter and we analyze its usage relative to other neurotransmitters within the context of the entire connectome and within specific network motifs embedded in the connectome. We reveal several dynamic aspects of cholinergic neurotransmitter identity, including a sexually dimorphic glutamatergic to cholinergic neurotransmitter switch in a sex-shared interneuron. An expression pattern analysis of ACh-gated anion channels furthermore suggests that ACh may also operate very broadly as an inhibitory neurotransmitter. As a first application of this comprehensive neurotransmitter map, we identify transcriptional regulatory mechanisms that control cholinergic neurotransmitter identity and cholinergic circuit assembly. DOI:http://dx.doi.org/10.7554/eLife.12432.001 To better understand the nervous system—the most complex of all the body’s organs—scientists have begun to painstakingly map its many features. These maps can then be used as a basis for understanding how the nervous system develops and works. Researchers have mapped the connections – called synapses – between all the nerve cells in the nervous system of a simple worm called Caenorhabditis elegans. Cells communicate by releasing chemicals called neurotransmitters across the synapses, but it is not fully known which types of neurotransmitters are released across each of the synapses in C. elegans. Now, Pereira et al. have mapped all worm nerve cells that use a neurotransmitter called acetylcholine by fluorescently marking proteins that synthesize and transport the neurotransmitter. This map revealed that 52 of the 118 types of nerve cells in the worm use acetylcholine, making it the most widely used neurotransmitter. This information was then combined with the findings of previous work that investigated which nerve cells release some other types of neurotransmitters. The combined data mean that it is now known which neurotransmitter is used for signaling by over 90% of the nerve cells in C. elegans. Using the map, Pereira et al. found that some neurons release different neurotransmitters in the different sexes of the worm. Additionally, the experiments revealed a set of proteins that cause the nerve cells to produce acetylcholine. Some of these proteins affect the fates of connected nerve cells. Overall, this information will allow scientists to more precisely manipulate specific cells or groups of cells in the worm nervous system to investigate how the nervous system develops and is regulated. DOI:http://dx.doi.org/10.7554/eLife.12432.002
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Affiliation(s)
- Laura Pereira
- Department of Biological Sciences, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Paschalis Kratsios
- Department of Biological Sciences, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Esther Serrano-Saiz
- Department of Biological Sciences, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Hila Sheftel
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Avi E Mayo
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - David H Hall
- Department of Neuroscience, Albert Einstein College of Medicine, New York, United States
| | - John G White
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Brigitte LeBoeuf
- Department of Biology, Texas A&M University, College Station, United States
| | - L Rene Garcia
- Department of Biology, Texas A&M University, College Station, United States.,Howard Hughes Medical Institute, Texas A&M University, College Station, United States
| | - Uri Alon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Howard Hughes Medical Institute, Columbia University, New York, United States
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29
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Chang YJ, Burton T, Ha L, Huang Z, Olajubelo A, Li C. Modulation of Locomotion and Reproduction by FLP Neuropeptides in the Nematode Caenorhabditis elegans. PLoS One 2015; 10:e0135164. [PMID: 26406995 PMCID: PMC4583311 DOI: 10.1371/journal.pone.0135164] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/18/2015] [Indexed: 11/18/2022] Open
Abstract
Neuropeptides function in animals to modulate most, if not all, complex behaviors. In invertebrates, neuropeptides can function as the primary neurotransmitter of a neuron, but more generally they co-localize with a small molecule neurotransmitter, as is commonly seen in vertebrates. Because a single neuron can express multiple neuropeptides and because neuropeptides can bind to multiple G protein-coupled receptors, neuropeptide actions increase the complexity by which the neural connectome can be activated or inhibited. Humans are estimated to have 90 plus neuropeptide genes; by contrast, nematodes, a relatively simple organism, have a slightly larger complement of neuropeptide genes. For instance, the nematode Caenorhabditis elegans has over 100 neuropeptide-encoding genes, of which at least 31 genes encode peptides of the FMRFamide family. To understand the function of this large FMRFamide peptide family, we isolated knockouts of different FMRFamide-encoding genes and generated transgenic animals in which the peptides are overexpressed. We assayed these animals on two basic behaviors: locomotion and reproduction. Modulating levels of different neuropeptides have strong as well as subtle effects on these behaviors. These data suggest that neuropeptides play critical roles in C. elegans to fine tune neural circuits controlling locomotion and reproduction.
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Affiliation(s)
- Yan-Jung Chang
- Department of Biology, City College of New York, City University of New York, New York, New York 10031, United States of America
| | - Tina Burton
- Department of Biology, City College of New York, City University of New York, New York, New York 10031, United States of America
| | - Lawrence Ha
- Department of Biology, City College of New York, City University of New York, New York, New York 10031, United States of America
| | - Zi Huang
- Department of Biology, City College of New York, City University of New York, New York, New York 10031, United States of America
| | - Adewale Olajubelo
- Department of Biology, City College of New York, City University of New York, New York, New York 10031, United States of America
| | - Chris Li
- Department of Biology, City College of New York, City University of New York, New York, New York 10031, United States of America
- The Graduate Center, City University of New York, New York, New York 10031, United States of America
- * E-mail:
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30
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Kim J, Yeon J, Choi SK, Huh YH, Fang Z, Park SJ, Kim MO, Ryoo ZY, Kang K, Kweon HS, Jeon WB, Li C, Kim K. The Evolutionarily Conserved LIM Homeodomain Protein LIM-4/LHX6 Specifies the Terminal Identity of a Cholinergic and Peptidergic C. elegans Sensory/Inter/Motor Neuron-Type. PLoS Genet 2015; 11:e1005480. [PMID: 26305787 PMCID: PMC4549117 DOI: 10.1371/journal.pgen.1005480] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 07/31/2015] [Indexed: 02/01/2023] Open
Abstract
The expression of specific transcription factors determines the differentiated features of postmitotic neurons. However, the mechanism by which specific molecules determine neuronal cell fate and the extent to which the functions of transcription factors are conserved in evolution are not fully understood. In C. elegans, the cholinergic and peptidergic SMB sensory/inter/motor neurons innervate muscle quadrants in the head and control the amplitude of sinusoidal movement. Here we show that the LIM homeobox protein LIM-4 determines neuronal characteristics of the SMB neurons. In lim-4 mutant animals, expression of terminal differentiation genes, such as the cholinergic gene battery and the flp-12 neuropeptide gene, is completely abolished and thus the function of the SMB neurons is compromised. LIM-4 activity promotes SMB identity by directly regulating the expression of the SMB marker genes via a distinct cis-regulatory motif. Two human LIM-4 orthologs, LHX6 and LHX8, functionally substitute for LIM-4 in C. elegans. Furthermore, C. elegans LIM-4 or human LHX6 can induce cholinergic and peptidergic characteristics in the human neuronal cell lines. Our results indicate that the evolutionarily conserved LIM-4/LHX6 homeodomain proteins function in generation of precise neuronal subtypes.
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Affiliation(s)
- Jinmahn Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Jihye Yeon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Seong-Kyoon Choi
- Laboratory of Biochemistry and Cellular Engineering, Division of NanoBio Technology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Yang Hoon Huh
- Nano-Bio Electron Microscopy Research Group, Korea Basic Science Institute, Daejeon, Korea
| | - Zi Fang
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Seo Jin Park
- School of Life Sciences, KNU Creative BioResearch Group (BK21 plus program), School of Animal BT Science, College of Natural Sciences, Kyungpook National University, Daegu, Korea
| | - Myoung Ok Kim
- School of Life Sciences, KNU Creative BioResearch Group (BK21 plus program), School of Animal BT Science, College of Natural Sciences, Kyungpook National University, Daegu, Korea
| | - Zae Young Ryoo
- School of Life Sciences, KNU Creative BioResearch Group (BK21 plus program), School of Animal BT Science, College of Natural Sciences, Kyungpook National University, Daegu, Korea
| | - Kyeongjin Kang
- Department of Anatomy and Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan School of Medicine, Gyeonggi-Do, Korea
| | - Hee-Seok Kweon
- Nano-Bio Electron Microscopy Research Group, Korea Basic Science Institute, Daejeon, Korea
| | - Won Bae Jeon
- Laboratory of Biochemistry and Cellular Engineering, Division of NanoBio Technology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Chris Li
- Department of Biology, City College of the City University of New York, New York, New York, United States of America
| | - Kyuhyung Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
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31
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Howell K, White JG, Hobert O. Spatiotemporal control of a novel synaptic organizer molecule. Nature 2015; 523:83-7. [PMID: 26083757 PMCID: PMC9134992 DOI: 10.1038/nature14545] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 05/12/2015] [Indexed: 12/13/2022]
Abstract
Synapse formation is a process tightly controlled in space and time. How gene regulatory mechanisms specify spatial and temporal aspects of synapse formation is not well understood. In the nematode C.elegans, two subtypes of the D-type inhibitory motor neuron (MN) classes, the dorsal D (DD) and ventral D (VD) neurons, extend axons along both the dorsal and ventral nerve cords 1. The embryonically generated DD MNs initially innervate ventral muscles in the first (L1) larval stage and receive their synaptic input from cholinergic MNs in the dorsal cord. They rewire by the end of the L1 molt to innervate dorsal muscles and to be innervated by newly formed ventral cholinergic MNs 1. VD MNs develop after the L1 molt; they take over the innervation of ventral muscles and receive their synaptic input from dorsal cholinergic MNs. We show here that the spatiotemporal control of synaptic wiring of the D-type neurons is controlled by an intersectional transcriptional strategy in which the UNC-30 Pitx-type homeodomain transcription factor acts together in embryonic and early larval stages with the temporally controlled LIN-14 transcription factor to prevent premature synapse rewiring of the DD MNs and, together with the UNC-55 nuclear hormone receptor, to prevent aberrant VD synaptic wiring in later larval and adult stages. A key effector of this intersectional transcription factor combination is a novel synaptic organizer molecule, the single immunoglobulin domain protein OIG-1. OIG-1 is perisynaptically localized along the synaptic outputs of the D-type MNs in a temporally controlled manner and is required for appropriate selection of both pre- and post-synaptic partners.
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32
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Transcriptional coordination of synaptogenesis and neurotransmitter signaling. Curr Biol 2015; 25:1282-95. [PMID: 25913400 DOI: 10.1016/j.cub.2015.03.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 02/10/2015] [Accepted: 03/18/2015] [Indexed: 11/21/2022]
Abstract
During nervous system development, postmitotic neurons face the challenge of generating and structurally organizing specific synapses with appropriate synaptic partners. An important unexplored question is whether the process of synaptogenesis is coordinated with the adoption of specific signaling properties of a neuron. Such signaling properties are defined by the neurotransmitter system that a neuron uses to communicate with postsynaptic partners, the neurotransmitter receptor type used to receive input from presynaptic neurons, and, potentially, other sensory receptors that activate a neuron. Elucidating the mechanisms that coordinate synaptogenesis, neuronal activation, and neurotransmitter signaling in a postmitotic neuron represents one key approach to understanding how neurons develop as functional units. Using the SAB class of Caenorhabditis elegans motor neurons as a model system, we show here that the phylogenetically conserved COE-type transcription factor UNC-3 is required for synaptogenesis. UNC-3 directly controls the expression of the ADAMTS-like protein MADD-4/Punctin, a presynaptically secreted synapse-organizing molecule that clusters postsynaptic receptors. UNC-3 also controls the assembly of presynaptic specializations and ensures the coordinated expression of enzymes and transporters that define the cholinergic neurotransmitter identity of the SAB neurons. Furthermore, synaptic output properties of the SAB neurons are coordinated with neuronal activation and synaptic input, as evidenced by UNC-3 also regulating the expression of ionotropic neurotransmitter receptors and putative stretch receptors. Our study shows how synaptogenesis and distinct, function-defining signaling features of a postmitotic neuron are hardwired together through coordinated transcriptional control.
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33
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Hamakawa M, Uozumi T, Ueda N, Iino Y, Hirotsu T. A role for Ras in inhibiting circular foraging behavior as revealed by a new method for time and cell-specific RNAi. BMC Biol 2015; 13:6. [PMID: 25603799 PMCID: PMC4321700 DOI: 10.1186/s12915-015-0114-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/09/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The nematode worm Caenorhabditis elegans, in which loss-of-function mutants and RNA interference (RNAi) models are available, is a model organism useful for analyzing effects of genes on various life phenomena, including behavior. In particular, RNAi is a powerful tool that enables time- or cell-specific knockdown via heat shock-inducible RNAi or cell-specific RNAi. However, conventional RNAi is insufficient for investigating pleiotropic genes with various sites of action and life stage-dependent functions. RESULTS Here, we investigated the Ras gene for its role in exploratory behavior in C. elegans. We found that, under poor environmental conditions, mutations in the Ras-MAPK signaling pathway lead to circular locomotion instead of normal exploratory foraging. Spontaneous foraging is regulated by a neural circuit composed of three classes of neurons: IL1, OLQ, and RMD, and we found that Ras functions in this neural circuit to modulate the direction of locomotion. We further observed that Ras plays an essential role in the regulation of GLR-1 glutamate receptor localization in RMD neurons. To investigate the temporal- and cell-specific profiles of the functions of Ras, we developed a new RNAi method that enables simultaneous time- and cell-specific knockdown. In this method, one RNA strand is expressed by a cell-specific promoter and the other by a heat shock promoter, resulting in only expression of double-stranded RNA in the target cell when heat shock is induced. This technique revealed that control of GLR-1 localization in RMD neurons requires Ras at the adult stage. Further, we demonstrated the application of this method to other genes. CONCLUSIONS We have established a new RNAi method that performs simultaneous time- and cell-specific knockdown and have applied this to reveal temporal profiles of the Ras-MAPK pathway in the control of exploratory behavior under poor environmental conditions.
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Affiliation(s)
- Masayuki Hamakawa
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Takayuki Uozumi
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Naoko Ueda
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Yuichi Iino
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Takaaki Hirotsu
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, 812-8581, Japan. .,Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan. .,Department of Biology, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan. .,Division of Applied Medical Sensing, Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka, 819-0395, Japan.
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Abstract
The essential neurotransmitter acetylcholine functions throughout the animal kingdom. In Caenorhabditis elegans, the acetylcholine biosynthetic enzyme [choline acetyltransferase (ChAT)] and vesicular transporter [vesicular acetylcholine transporter (VAChT)] are encoded by the cha-1 and unc-17 genes, respectively. These two genes compose a single complex locus in which the unc-17 gene is nested within the first intron of cha-1, and the two gene products arise from a common pre-messenger RNA (pre-mRNA) by alternative splicing. This genomic organization, known as the cholinergic gene locus (CGL), is conserved throughout the animal kingdom, suggesting that the structure is important for the regulation and function of these genes. However, very little is known about CGL regulation in any species. We now report the identification of an unusual type of splicing regulation in the CGL of C. elegans, mediated by two pairs of complementary sequence elements within the locus. We show that both pairs of elements are required for efficient splicing to the distal acceptor, and we also demonstrate that proper distal splicing depends more on sequence complementarity within each pair of elements than on the sequences themselves. We propose that these sequence elements are able to form stem-loop structures in the pre-mRNA; such structures would favor specific splicing alternatives and thus regulate CGL splicing. We have identified complementary elements at comparable locations in the genomes of representative species of other animal phyla; we suggest that this unusual regulatory mechanism may be a general feature of CGLs.
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35
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Ramakrishnan K, Okkema PG. Regulation of C. elegans neuronal differentiation by the ZEB-family factor ZAG-1 and the NK-2 homeodomain factor CEH-28. PLoS One 2014; 9:e113893. [PMID: 25474681 PMCID: PMC4256384 DOI: 10.1371/journal.pone.0113893] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/02/2014] [Indexed: 12/28/2022] Open
Abstract
The C. elegans pharyngeal neuron M4 is a multi-functional cell that acts as a cholinergic motor neuron to stimulate peristaltic pharyngeal muscle contraction and as a neuroendocrine cell secreting neuropeptides and growth factors to affect other cells both inside and outside the pharynx. The conserved transcription factors ZAG-1 and CEH-28 are co-expressed in M4 through most of development, and here we examine how these factors contribute to M4 differentiation. We find ZAG-1 functions upstream of CEH-28 in a branched pathway to activate expression of different sets of M4 differentiation markers. CEH-28 activates expression of the growth factor genes dbl-1 and egl-17, and the neuropeptide genes flp-5 and flp-2, while ZAG-1 activates expression of the serotonin receptor ser-7, as well as expression of ceh-28 and its downstream targets. Other markers of M4 differentiation are expressed normally in both zag-1 and ceh-28 mutants, including the neuropeptide gene flp-21 and the acetylcholine biosynthetic gene unc-17. Unlike ceh-28 mutants, zag-1 mutants completely lack peristaltic muscle contractions resulting from broader defects in M4 differentiation. Despite these defects, neither ZAG-1 nor CEH-28 are terminal selectors of the M4 phenotype, and we suggest they function in a hierarchy to regulate different aspects of M4 differentiation.
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Affiliation(s)
- Kalpana Ramakrishnan
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Peter G. Okkema
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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36
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Kalis AK, Kissiov DU, Kolenbrander ES, Palchick Z, Raghavan S, Tetreault BJ, Williams E, Loer CM, Wolff JR. Patterning of sexually dimorphic neurogenesis in the caenorhabditis elegans ventral cord by Hox and TALE homeodomain transcription factors. Dev Dyn 2014; 243:159-71. [PMID: 24115648 DOI: 10.1002/dvdy.24064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 09/16/2013] [Accepted: 09/16/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Reproduction in animals requires development of distinct neurons in each sex. In C. elegans, most ventral cord neurons (VCNs) are present in both sexes, with the exception of six hermaphrodite-specific neurons (VCs) and nine pairs of male-specific neurons (CAs and CPs) that arise from analogous precursor cells. How are the activities of sexual regulators and mediators of neuronal survival, division, and fate coordinated to generate sex-specificity in VCNs? RESULTS To address this, we have developed a toolkit of VCN markers that allows us to examine sex-specific neurogenesis, asymmetric fates of daughters of a neuroblast division, and regional specification on the anteroposterior axis. Here, we describe the roles of the Hox transcription factors LIN-39 and MAB-5 in promoting survival, differentiation, and regionalization of VCNs. We also find that the TALE class homeodomain proteins CEH-20 and UNC-62 contribute to specification of neurotransmitter fate in males. Furthermore, we identify that VCN sex is determined during the L1 larval stage. CONCLUSIONS These findings, combined with future analyses made possible by the suite of VCN markers described here, will elucidate how Hox-mediated cell fate decisions and sex determination intersect to influence development of neuronal sex differences.
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Gjorgjieva J, Biron D, Haspel G. Neurobiology of Caenorhabditis elegans Locomotion: Where Do We Stand? Bioscience 2014; 64:476-486. [PMID: 26955070 PMCID: PMC4776678 DOI: 10.1093/biosci/biu058] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Animals use a nervous system for locomotion in some stage of their life cycle. The nematode Caenorhabditis elegans, a major animal model for almost all fields of experimental biology, has long been used for detailed studies of genetic and physiological locomotion mechanisms. Of its 959 somatic cells, 302 are neurons that are identifiable by lineage, location, morphology, and neurochemistry in every adult hermaphrodite. Of those, 75 motoneurons innervate body wall muscles that provide the thrust during locomotion. In this Overview, we concentrate on the generation of either forward- or backward-directed motion during crawling and swimming. We describe locomotion behavior, the parts constituting the locomotion system, and the relevant neuronal connectivity. Because it is not yet fully understood how these components combine to generate locomotion, we discuss competing hypotheses and models.
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Affiliation(s)
- Julijana Gjorgjieva
- Julijana Gjorgjieva is a postdoctoral research fellow at the Center for Brain Science of Harvard University, in Cambridge, Massachusetts. She uses theoretical and numerical tools to understand how developing neural circuits wire to perform a particular function, from the mammalian visual system to the motor system of small invertebrates. David Biron is a physicist at the University of Chicago, Illinois. He studies the sleep of the roundworm Caenorhabditis elegans and related problems in biological physics. Gal Haspel ( ) is a neuroethologist at the New Jersey Institute of Technology, in Newark. He studies the activity, connectivity and recovery from injury of the neuronal network that underlie locomotion in the nematode Caenorhabditis elegans
| | - David Biron
- Julijana Gjorgjieva is a postdoctoral research fellow at the Center for Brain Science of Harvard University, in Cambridge, Massachusetts. She uses theoretical and numerical tools to understand how developing neural circuits wire to perform a particular function, from the mammalian visual system to the motor system of small invertebrates. David Biron is a physicist at the University of Chicago, Illinois. He studies the sleep of the roundworm Caenorhabditis elegans and related problems in biological physics. Gal Haspel ( ) is a neuroethologist at the New Jersey Institute of Technology, in Newark. He studies the activity, connectivity and recovery from injury of the neuronal network that underlie locomotion in the nematode Caenorhabditis elegans
| | - Gal Haspel
- Julijana Gjorgjieva is a postdoctoral research fellow at the Center for Brain Science of Harvard University, in Cambridge, Massachusetts. She uses theoretical and numerical tools to understand how developing neural circuits wire to perform a particular function, from the mammalian visual system to the motor system of small invertebrates. David Biron is a physicist at the University of Chicago, Illinois. He studies the sleep of the roundworm Caenorhabditis elegans and related problems in biological physics. Gal Haspel ( ) is a neuroethologist at the New Jersey Institute of Technology, in Newark. He studies the activity, connectivity and recovery from injury of the neuronal network that underlie locomotion in the nematode Caenorhabditis elegans
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Cohen E, Chatzigeorgiou M, Husson SJ, Steuer-Costa W, Gottschalk A, Schafer WR, Treinin M. Caenorhabditis elegans nicotinic acetylcholine receptors are required for nociception. Mol Cell Neurosci 2014; 59:85-96. [PMID: 24518198 PMCID: PMC4258610 DOI: 10.1016/j.mcn.2014.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/07/2014] [Accepted: 02/01/2014] [Indexed: 11/18/2022] Open
Abstract
Polymodal nociceptors sense and integrate information on injurious mechanical, thermal, and chemical stimuli. Chemical signals either activate nociceptors or modulate their responses to other stimuli. One chemical known to activate or modulate responses of nociceptors is acetylcholine (ACh). Across evolution nociceptors express subunits of the nicotinic acetylcholine receptor (nAChR) family, a family of ACh-gated ion channels. The roles of ACh and nAChRs in nociceptor function are, however, poorly understood. Caenorhabditis elegans polymodal nociceptors, PVD, express nAChR subunits on their sensory arbor. Here we show that mutations reducing ACh synthesis and mutations in nAChR subunits lead to defects in PVD function and morphology. A likely cause for these defects is a reduction in cytosolic calcium measured in ACh and nAChR mutants. Indeed, overexpression of a calcium pump in PVD mimics defects in PVD function and morphology found in nAChR mutants. Our results demonstrate, for the first time, a central role for nAChRs and ACh in nociceptor function and suggest that calcium permeating via nAChRs facilitates activity of several signaling pathways within this neuron.
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Affiliation(s)
- Emiliano Cohen
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University - Hadassah Medical School, Jerusalem 91120, Israel
| | - Marios Chatzigeorgiou
- Cell Biology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge UK
| | - Steven J Husson
- Functional Genomics and Proteomics, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium; SPHERE - Systemic Physiological & Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171/U7, B-2020 Antwerp, Belgium
| | - Wagner Steuer-Costa
- Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 15, D-60438 Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 15, D-60438 Frankfurt, Germany
| | - William R Schafer
- Cell Biology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge UK
| | - Millet Treinin
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University - Hadassah Medical School, Jerusalem 91120, Israel.
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Taki FA, Pan X, Zhang B. Chronic nicotine exposure systemically alters microRNA expression profiles during post-embryonic stages in Caenorhabditis elegans. J Cell Physiol 2014; 229:79-89. [PMID: 23765240 PMCID: PMC3925673 DOI: 10.1002/jcp.24419] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/06/2013] [Indexed: 01/04/2023]
Abstract
Tobacco smoking is associated with many diseases. Addiction is of the most notorious tobacco-related syndrome and is mainly attributed to nicotine. In this study, we employed Caenorhabditis elegans as a biological model to systemically investigate the effect of chronic nicotine exposure on microRNA (miRNA) expression profile and their regulated biochemical pathways. Nicotine treatment (20 µM and 20 mM) was limited to the post-embryonic stage from L1 to L4 (∼31 h) period after which worms were collected for genome-wide miRNA profiling. Our results show that nicotine significantly altered the expression patterns of 40 miRNAs. The effect was proportional to the nicotine dose and was expected to have an additive, more robust response. Based on pathway enrichment analyses coupled with nicotine-induced miRNA patterns, we inferred that miRNAs as a system mediates "regulatory hormesis", manifested in biphasic behavioral and physiological phenotypes. We proposed a model where nicotine addiction is mediated by miRNAs' regulation of fos-1 and is maintained by epigenetic factors. Thus, our study offers new insights for a better understanding of the sensitivity of early developmental stages to nicotine.
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Affiliation(s)
- Faten A Taki
- Department of Biology, East Carolina University, Greenville, NC 27858
| | - Xiaoping Pan
- Department of Biology, East Carolina University, Greenville, NC 27858
| | - Baohong Zhang
- Department of Biology, East Carolina University, Greenville, NC 27858
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40
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Extrasynaptic muscarinic acetylcholine receptors on neuronal cell bodies regulate presynaptic function in Caenorhabditis elegans. J Neurosci 2013; 33:14146-59. [PMID: 23986249 DOI: 10.1523/jneurosci.1359-13.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Acetylcholine (ACh) is a potent neuromodulator in the brain, and its effects on cognition and memory formation are largely performed through muscarinic acetylcholine receptors (mAChRs). mAChRs are often preferentially distributed on specialized membrane regions in neurons, but the significance of mAChR localization in modulating neuronal function is not known. Here we show that the Caenorhabditis elegans homolog of the M1/M3/M5 family of mAChRs, gar-3, is expressed in cholinergic motor neurons, and GAR-3-GFP fusion proteins localize to cell bodies where they are enriched at extrasynaptic regions that are in contact with the basal lamina. The GAR-3 N-terminal extracellular domain is necessary and sufficient for this asymmetric distribution, and mutation of a predicted N-linked glycosylation site within the N-terminus disrupts GAR-3-GFP localization. In transgenic animals expressing GAR-3 variants that are no longer asymmetrically localized, synaptic transmission at neuromuscular junctions is impaired and there is a reduction in the abundance of the presynaptic protein sphingosine kinase at release sites. Finally, GAR-3 can be activated by endogenously produced ACh released from neurons that do not directly contact cholinergic motor neurons. Together, our results suggest that humoral activation of asymmetrically localized mAChRs by ACh is an evolutionarily conserved mechanism by which ACh modulates neuronal function.
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Serrano-Saiz E, Poole RJ, Felton T, Zhang F, De La Cruz ED, Hobert O. Modular control of glutamatergic neuronal identity in C. elegans by distinct homeodomain proteins. Cell 2013; 155:659-73. [PMID: 24243022 DOI: 10.1016/j.cell.2013.09.052] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/14/2013] [Accepted: 09/23/2013] [Indexed: 10/26/2022]
Abstract
The choice of using one of many possible neurotransmitter systems is a critical step in defining the identity of an individual neuron type. We show here that the key defining feature of glutamatergic neurons, the vesicular glutamate transporter EAT-4/VGLUT, is expressed in 38 of the 118 anatomically defined neuron classes of the C. elegans nervous system. We show that distinct cis-regulatory modules drive expression of eat-4/VGLUT in distinct glutamatergic neuron classes. We identify 13 different transcription factors, 11 of them homeodomain proteins, that act in distinct combinations in 25 different glutamatergic neuron classes to initiate and maintain eat-4/VGLUT expression. We show that the adoption of a glutamatergic phenotype is linked to the adoption of other terminal identity features of a neuron, including cotransmitter phenotypes. Examination of mouse orthologs of these homeodomain proteins resulted in the identification of mouse LHX1 as a regulator of glutamatergic neurons in the brainstem.
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Affiliation(s)
- Esther Serrano-Saiz
- Department of Biochemistry and Molecular Biophysics, HHMI, Columbia University Medical Center, New York, NY 10032, USA.
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Rose JK, Miller MK, Crane SA, Hope KA, Pittman PG. Parental and larval exposure to nicotine modulate spontaneous activity as well as cholinergic and GABA receptor expression in adult C. elegans. Neurotoxicol Teratol 2013; 39:122-7. [PMID: 23906944 DOI: 10.1016/j.ntt.2013.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 07/09/2013] [Accepted: 07/23/2013] [Indexed: 10/26/2022]
Abstract
Early nicotine exposure has been associated with many long-term consequences that include neuroanatomical alterations, as well as behavioral and cognitive deficits. To describe the effects of early nicotine exposure in Caenorhabditis elegans, the current study observed spontaneous locomotor activity (i.e., reversals) either in the presence or absence of nicotine. Expression of acr-16 (a nicotinic receptor subunit) and a β-like GABA(A) receptor subunit, gab-1, were also examined with RT-PCR. Worms were exposed to nicotine (30 μM) throughout "zygote formation" (period that includes oocyte maturation, ovulation and fertilization), from hatching to adulthood ("larval development") or across both zygote and larval development. Adult larval-exposed worms only showed an increase in spontaneous behavior when tested on nicotine (p<0.001) but levels of activity similar to controls when tested on plain plates (p>0.30). Larval-exposed worms also showed control levels of acr-16 nicotinic receptor expression (p>0.10) but increased gab-1 expression relative to controls (p<0.01). In contrast, zygote-exposed and zygote- plus larval-exposed worms showed a similar increase in spontaneous behavior on plain plates (p<0.001 and p=0.001, respectively) but control levels of responding when tested on nicotine (p>0.90 for each). However, expression of acr-16 and gab-1 was downregulated in zygote-exposed (p<0.01 and p<0.05, respectively) and significantly upregulated in the zygote- plus larval-exposed worms (p<0.000 for each); most surprising was the over five-fold increase in gab-1 expression. These results suggest that spontaneous motor behavior and receptor expression are differentially modulated by nicotine exposure during larval development and/or zygote formation. As well, these findings demonstrate that C. elegans, as a model system, is also sensitive to nicotine exposure during early development and provides the basis for future research to uncover specific mechanisms by which early nicotine exposure modifies neuronal signaling and alters behavior.
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Affiliation(s)
- Jacqueline K Rose
- Program in Behavioral Neuroscience and Department of Psychology, Western Washington University, 516 High St., Bellingham, WA, USA.
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Abstract
Transforming Growth Factor-β (TGF-β) superfamily ligands regulate many aspects of cell identity, function, and survival in multicellular animals. Genes encoding five TGF-β family members are present in the genome of C. elegans. Two of the ligands, DBL-1 and DAF-7, signal through a canonical receptor-Smad signaling pathway; while a third ligand, UNC-129, interacts with a noncanonical signaling pathway. No function has yet been associated with the remaining two ligands. Here we summarize these signaling pathways and their biological functions.
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Affiliation(s)
- Tina L Gumienny
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX 77843, USA
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Philbrook A, Barbagallo B, Francis MM. A tale of two receptors: Dual roles for ionotropic acetylcholine receptors in regulating motor neuron excitation and inhibition. WORM 2013; 2:e25765. [PMID: 24778941 PMCID: PMC3875653 DOI: 10.4161/worm.25765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 07/15/2013] [Indexed: 11/29/2022]
Abstract
Nicotinic or ionotropic acetylcholine receptors (iAChRs) mediate excitatory signaling throughout the nervous system, and the heterogeneity of these receptors contributes to their multifaceted roles. Our recent work has characterized a single iAChR subunit, ACR-12, which contributes to two distinct iAChR subtypes within the C. elegans motor circuit. These two receptor subtypes regulate the coordinated activity of excitatory (cholinergic) and inhibitory (GABAergic) motor neurons. We have shown that the iAChR subunit ACR-12 is differentially expressed in both cholinergic and GABAergic motor neurons within the motor circuit. In cholinergic motor neurons, ACR-12 is incorporated into the previously characterized ACR-2 heteromeric receptor, which shows non-synaptic localization patterns and plays a modulatory role in controlling circuit function.1 In contrast, a second population of ACR-12-containing receptors in GABAergic motor neurons, ACR-12GABA, shows synaptic expression and regulates inhibitory signaling.2 Here, we discuss the two ACR-12-containing receptor subtypes, their distinct expression patterns, and functional roles in the C. elegans motor circuit. We anticipate our continuing studies of iAChRs in the C. elegans motor circuit will lead to novel insights into iAChR function in the nervous system as well as mechanisms for their regulation.
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Affiliation(s)
- Alison Philbrook
- Department of Neurobiology; UMass Medical School; Worcester, MA USA
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Hyperactivation of B-type motor neurons results in aberrant synchrony of the Caenorhabditis elegans motor circuit. J Neurosci 2013; 33:5319-25. [PMID: 23516296 DOI: 10.1523/jneurosci.4017-12.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Excitatory acetylcholine motor neurons drive Caenorhabditis elegans locomotion. Coordinating the activation states of the backward-driving A and forward-driving B class motor neurons is critical for generating sinusoidal and directional locomotion. Here, we show by in vivo calcium imaging that expression of a hyperactive, somatodendritic ionotropic acetylcholine receptor ACR-2(gf) in A and B class motor neurons induces aberrant synchronous activity in both ventral- and dorsal-innervating B and A class motor neurons. Expression of ACR-2(gf) in either ventral- or dorsal-innervating B neurons is sufficient for triggering the aberrant synchrony that results in arrhythmic convulsions. Silencing of AVB, the premotor interneurons that innervate B motor neurons suppresses ACR-2(gf)-dependent convulsion; activating AVB by channelrhodopsin induces the onset of convulsion. These results support that the activity state of B motor neurons plays an instructive role for the coordination of motor circuit.
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46
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Sherlekar AL, Janssen A, Siehr MS, Koo PK, Caflisch L, Boggess M, Lints R. The C. elegans male exercises directional control during mating through cholinergic regulation of sex-shared command interneurons. PLoS One 2013; 8:e60597. [PMID: 23577128 PMCID: PMC3618225 DOI: 10.1371/journal.pone.0060597] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/28/2013] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Mating behaviors in simple invertebrate model organisms represent tractable paradigms for understanding the neural bases of sex-specific behaviors, decision-making and sensorimotor integration. However, there are few examples where such neural circuits have been defined at high resolution or interrogated. METHODOLOGY/PRINCIPAL FINDINGS Here we exploit the simplicity of the nematode Caenorhabditis elegans to define the neural circuits underlying the male's decision to initiate mating in response to contact with a mate. Mate contact is sensed by male-specific sensilla of the tail, the rays, which subsequently induce and guide a contact-based search of the hermaphrodite's surface for the vulva (the vulva search). Atypically, search locomotion has a backward directional bias so its implementation requires overcoming an intrinsic bias for forward movement, set by activity of the sex-shared locomotory system. Using optogenetics, cell-specific ablation- and mutant behavioral analyses, we show that the male makes this shift by manipulating the activity of command cells within this sex-shared locomotory system. The rays control the command interneurons through the male-specific, decision-making interneuron PVY and its auxiliary cell PVX. Unlike many sex-shared pathways, PVY/PVX regulate the command cells via cholinergic, rather than glutamatergic transmission, a feature that likely contributes to response specificity and coordinates directional movement with other cholinergic-dependent motor behaviors of the mating sequence. PVY/PVX preferentially activate the backward, and not forward, command cells because of a bias in synaptic inputs and the distribution of key cholinergic receptors (encoded by the genes acr-18, acr-16 and unc-29) in favor of the backward command cells. CONCLUSION/SIGNIFICANCE Our interrogation of male neural circuits reveals that a sex-specific response to the opposite sex is conferred by a male-specific pathway that renders subordinate, sex-shared motor programs responsive to mate cues. Circuit modifications of these types may make prominent contributions to natural variations in behavior that ultimately bring about speciation.
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Affiliation(s)
- Amrita L. Sherlekar
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Abbey Janssen
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Meagan S. Siehr
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Pamela K. Koo
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Laura Caflisch
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - May Boggess
- School of Mathematical and Statistical Sciences,Arizona State University, Tempe, Arizona, United States of America
| | - Robyn Lints
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
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Genetic interactions between UNC-17/VAChT and a novel transmembrane protein in Caenorhabditis elegans. Genetics 2012; 192:1315-25. [PMID: 23051648 DOI: 10.1534/genetics.112.145771] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The unc-17 gene encodes the vesicular acetylcholine transporter (VAChT) in Caenorhabditis elegans. unc-17 reduction-of-function mutants are small, slow growing, and uncoordinated. Several independent unc-17 alleles are associated with a glycine-to-arginine substitution (G347R), which introduces a positive charge in the ninth transmembrane domain (TMD) of UNC-17. To identify proteins that interact with UNC-17/VAChT, we screened for mutations that suppress the uncoordinated phenotype of UNC-17(G347R) mutants. We identified several dominant allele-specific suppressors, including mutations in the sup-1 locus. The sup-1 gene encodes a single-pass transmembrane protein that is expressed in a subset of neurons and in body muscles. Two independent suppressor alleles of sup-1 are associated with a glycine-to-glutamic acid substitution (G84E), resulting in a negative charge in the SUP-1 TMD. A sup-1 null mutant has no obvious deficits in cholinergic neurotransmission and does not suppress unc-17 mutant phenotypes. Bimolecular fluorescence complementation (BiFC) analysis demonstrated close association of SUP-1 and UNC-17 in synapse-rich regions of the cholinergic nervous system, including the nerve ring and dorsal nerve cords. These observations suggest that UNC-17 and SUP-1 are in close proximity at synapses. We propose that electrostatic interactions between the UNC-17(G347R) and SUP-1(G84E) TMDs alter the conformation of the mutant UNC-17 protein, thereby restoring UNC-17 function; this is similar to the interaction between UNC-17/VAChT and synaptobrevin.
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Casini A, Vaccaro R, D'Este L, Sakaue Y, Bellier JP, Kimura H, Renda TG. Immunolocalization of choline acetyltransferase of common type in the central brain mass of Octopus vulgaris. Eur J Histochem 2012; 56:e34. [PMID: 23027350 PMCID: PMC3493980 DOI: 10.4081/ejh.2012.e34] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 11/23/2022] Open
Abstract
Acetylcholine, the first neurotransmitter to be identified in the vertebrate frog, is widely distributed among the animal kingdom. The presence of a large amount of acetylcholine in the nervous system of cephalopods is well known from several biochemical and physiological studies. However, little is known about the precise distribution of cholinergic structures due to a lack of a suitable histochemical technique for detecting acetylcholine. The most reliable method to visualize the cholinergic neurons is the immunohistochemical localization of the enzyme choline acetyltransferase, the synthetic enzyme of acetylcholine. Following our previous study on the distribution patterns of cholinergic neurons in the Octopus vulgaris visual system, using a novel antibody that recognizes choline acetyltransferase of the common type (cChAT), now we extend our investigation on the octopus central brain mass. When applied on sections of octopus central ganglia, immunoreactivity for cChAT was detected in cell bodies of all central brain mass lobes with the notable exception of the subfrontal and subvertical lobes. Positive varicosed nerves fibers where observed in the neuropil of all central brain mass lobes.
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Affiliation(s)
- A Casini
- Laboratory of Immunohistochemistry Tindaro G. Renda Department of Anatomic, Histologic, Forensic and Locomotor Apparatus Sciences, Sapienza University of Rome, Italy.
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Mullen GP, Grundahl KM, Gu M, Watanabe S, Hobson RJ, Crowell JA, McManus JR, Mathews EA, Jorgensen EM, Rand JB. UNC-41/stonin functions with AP2 to recycle synaptic vesicles in Caenorhabditis elegans. PLoS One 2012; 7:e40095. [PMID: 22808098 PMCID: PMC3393740 DOI: 10.1371/journal.pone.0040095] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 05/31/2012] [Indexed: 11/20/2022] Open
Abstract
The recycling of synaptic vesicles requires the recovery of vesicle proteins and membrane. Members of the stonin protein family (Drosophila Stoned B, mammalian stonin 2) have been shown to link the synaptic vesicle protein synaptotagmin to the endocytic machinery. Here we characterize the unc-41 gene, which encodes the stonin ortholog in the nematode Caenorhabditis elegans. Transgenic expression of Drosophila stonedB rescues unc-41 mutant phenotypes, demonstrating that UNC-41 is a bona fide member of the stonin family. In unc-41 mutants, synaptotagmin is present in axons, but is mislocalized and diffuse. In contrast, UNC-41 is localized normally in synaptotagmin mutants, demonstrating a unidirectional relationship for localization. The phenotype of snt-1 unc-41 double mutants is stronger than snt-1 mutants, suggesting that UNC-41 may have additional, synaptotagmin-independent functions. We also show that unc-41 mutants have defects in synaptic vesicle membrane endocytosis, including a ∼50% reduction of vesicles in both acetylcholine and GABA motor neurons. These endocytic defects are similar to those observed in apm-2 mutants, which lack the µ2 subunit of the AP2 adaptor complex. However, no further reduction in synaptic vesicles was observed in unc-41 apm-2 double mutants, suggesting that UNC-41 acts in the same endocytic pathway as µ2 adaptin.
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Affiliation(s)
- Gregory P. Mullen
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Kiely M. Grundahl
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Mingyu Gu
- Howard Hughes Medical Institute and Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Shigeki Watanabe
- Howard Hughes Medical Institute and Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Robert J. Hobson
- Howard Hughes Medical Institute and Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - John A. Crowell
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - John R. McManus
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Eleanor A. Mathews
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Erik M. Jorgensen
- Howard Hughes Medical Institute and Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - James B. Rand
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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50
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Genes down-regulated in spaceflight are involved in the control of longevity in Caenorhabditis elegans. Sci Rep 2012; 2:487. [PMID: 22768380 PMCID: PMC3390002 DOI: 10.1038/srep00487] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 04/26/2012] [Indexed: 11/24/2022] Open
Abstract
How microgravitational space environments affect aging is not well understood. We observed that, in Caenorhabditis elegans, spaceflight suppressed the formation of transgenically expressed polyglutamine aggregates, which normally accumulate with increasing age. Moreover, the inactivation of each of seven genes that were down-regulated in space extended lifespan on the ground. These genes encode proteins that are likely related to neuronal or endocrine signaling: acetylcholine receptor, acetylcholine transporter, choline acetyltransferase, rhodopsin-like receptor, glutamate-gated chloride channel, shaker family of potassium channel, and insulin-like peptide. Most of them mediated lifespan control through the key longevity-regulating transcription factors DAF-16 or SKN-1 or through dietary-restriction signaling, singly or in combination. These results suggest that aging in C. elegans is slowed through neuronal and endocrine response to space environmental cues.
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