Proteolysis in Caenorhabditis elegans sex determination: cleavage of TRA-2A by TRA-3

The Caenorhabditis elegans tra-3 gene promotes female development in XX hermaphrodites and encodes an atypical calpain regulatory protease lacking calcium-binding EF hands. We report that despite the absence of EF hands, TRA-3 has calcium-dependent proteolytic activity and its proteolytic domain is essential for in vivo function. We show that the membrane protein TRA-2A, which promotes XX female development by repressing the masculinizing protein FEM-3, is a TRA-3 substrate. Cleavage of TRA-2A by TRA-3 generates a peptide predicted to have feminizing activity. These results indicate that proteolysis regulated by calcium may control some aspects of sexual cell fate in C. elegans.

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Combining single-cell RNA-sequencing with a molecular atlas unveils new markers for Caenorhabditis elegans neuron classes

Nucleic Acids Research ◽

10.1093/nar/gkaa486 ◽

2020 ◽

Cited By ~ 2

Author(s):

Ramiro Lorenzo ◽

Michiho Onizuka ◽

Matthieu Defrance ◽

Patrick Laurent

Keyword(s):

Caenorhabditis Elegans ◽

Single Cell ◽

Rna Sequencing ◽

Cell Fate ◽

Single Neuron ◽

Genetic Manipulations ◽

C Elegans ◽

Single Cell Rna Sequencing ◽

Normal Differentiation

Abstract Single-cell RNA-sequencing (scRNA-seq) of the Caenorhabditis elegans nervous system offers the unique opportunity to obtain a partial expression profile for each neuron within a known connectome. Building on recent scRNA-seq data and on a molecular atlas describing the expression pattern of ∼800 genes at the single cell resolution, we designed an iterative clustering analysis aiming to match each cell-cluster to the ∼100 anatomically defined neuron classes of C. elegans. This heuristic approach successfully assigned 97 of the 118 neuron classes to a cluster. Sixty two clusters were assigned to a single neuron class and 15 clusters grouped neuron classes sharing close molecular signatures. Pseudotime analysis revealed a maturation process occurring in some neurons (e.g. PDA) during the L2 stage. Based on the molecular profiles of all identified neurons, we predicted cell fate regulators and experimentally validated unc-86 for the normal differentiation of RMG neurons. Furthermore, we observed that different classes of genes functionally diversify sensory neurons, interneurons and motorneurons. Finally, we designed 15 new neuron class-specific promoters validated in vivo. Amongst them, 10 represent the only specific promoter reported to this day, expanding the list of neurons amenable to genetic manipulations.

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Rapid Deadenylation and Poly(A)-Dependent Translational Repression Mediated by the Caenorhabditis elegans tra-2 3′ Untranslated Region in XenopusEmbryos

Molecular and Cellular Biology ◽

10.1128/mcb.20.6.2129-2137.2000 ◽

2000 ◽

Vol 20 (6) ◽

pp. 2129-2137 ◽

Cited By ~ 26

Author(s):

Sunnie R. Thompson ◽

Elizabeth B. Goodwin ◽

Marvin Wickens

Keyword(s):

Caenorhabditis Elegans ◽

Cell Fate ◽

Translational Control ◽

Untranslated Region ◽

Specific Binding ◽

Translational Repression ◽

Female Development ◽

C Elegans ◽

Egg Extracts ◽

Eukaryotic Mrnas

ABSTRACT The 3′ untranslated region (3′UTR) of many eukaryotic mRNAs is essential for their control during early development. Negative translational control elements in 3′UTRs regulate pattern formation, cell fate, and sex determination in a variety of organisms.tra-2 mRNA in Caenorhabditis elegans is required for female development but must be repressed to permit spermatogenesis in hermaphrodites. Translational repression oftra-2 mRNA in C. elegans is mediated by tandemly repeated elements in its 3′UTR; these elements are called TGEs (for tra-2 and GLI element). To examine the mechanism of TGE-mediated repression, we first demonstrate that TGE-mediated translational repression occurs in Xenopus embryos and thatXenopus egg extracts contain a TGE-specific binding factor. Translational repression by the TGEs requires that the mRNA possess a poly(A) tail. We show that in C. elegans, the poly(A) tail of wild-type tra-2 mRNA is shorter than that of a mutant mRNA lacking the TGEs. To determine whether TGEs regulate poly(A) length directly, synthetic tra-2 3′UTRs with and without the TGEs were injected into Xenopus embryos. We find that TGEs accelerate the rate of deadenylation and permit the last 15 adenosines to be removed from the RNA, resulting in the accumulation of fully deadenylated molecules. We conclude that TGE-mediated translational repression involves either interference with poly(A)'s function in translation and/or regulated deadenylation.

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Interchangeability of Caenorhabditis elegans DSL proteins and intrinsic signalling activity of their extracellular domains in vivo

Development ◽

10.1242/dev.121.12.4275 ◽

1995 ◽

Vol 121 (12) ◽

pp. 4275-4282 ◽

Cited By ~ 14

Author(s):

K. Fitzgerald ◽

I. Greenwald

Keyword(s):

Caenorhabditis Elegans ◽

Cell Fate ◽

Cell Interactions ◽

Regulatory Sequences ◽

Cell Fate Decisions ◽

C Elegans ◽

Dsl Ligands ◽

Mediate Cell ◽

Intracellular Domains

Ligands of the Delta/Serrate/lag-2 (DSL) family and their receptors, members of the lin-12/Notch family, mediate cell-cell interactions that specify cell fate in invertebrates and vertebrates. In C. elegans, two DSL genes, lag-2 and apx-1, influence different cell fate decisions during development. Here we show that APX-1 can fully substitute for LAG-2 when expressed under the control of lag-2 regulatory sequences. In addition, we demonstrate that truncated forms lacking the transmembrane and intracellular domains of both LAG-2 and APX-1 can also substitute for endogenous lag-2 activity. Moreover, we provide evidence that these truncated forms are secreted and able to activate LIN-12 and GLP-1 ectopically. Finally, we show that expression of a secreted DSL domain alone may enhance endogenous LAG-2 signalling. Our data suggest ways that activated forms of DSL ligands in other systems may be created.

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Phytobacter diazotrophicus from Intestine of Caenorhabditis elegans Confers Colonization-Resistance against Bacillus nematocida Using Flagellin (FliC) as an Inhibition Factor

Pathogens ◽

10.3390/pathogens11010082 ◽

2022 ◽

Vol 11 (1) ◽

pp. 82

Author(s):

Qiuhong Niu ◽

Suyao Liu ◽

Mingshen Yin ◽

Shengwei Lei ◽

Fabio Rezzonico ◽

...

Keyword(s):

Cell Division ◽

Caenorhabditis Elegans ◽

Membrane Protein ◽

Bacterial Cells ◽

Colonization Resistance ◽

Flic Gene ◽

C Elegans ◽

Free Living Nematode ◽

Bacterium Bacillus

Symbiotic microorganisms in the intestinal tract can influence the general fitness of their hosts and contribute to protecting them against invading pathogens. In this study, we obtained isolate Phytobacter diazotrophicus SCO41 from the gut of free-living nematode Caenorhabditis elegans that displayed strong colonization-resistance against invading biocontrol bacterium Bacillus nematocida B16. The colonization-resistance phenotype was found to be mediated by a 37-kDa extracellular protein that was identified as flagellin (FliC). With the help of genome information, the fliC gene was cloned and heterologously expressed in E. coli. It could be shown that the B. nematocida B16 grows in chains rather than in planktonic form in the presence of FliC. Scanning Electronic Microscopy results showed that protein FliC-treated B16 bacterial cells are thinner and longer than normal cells. Localization experiments confirmed that the protein FliC is localized in both the cytoplasm and the cell membrane of B16 strain, in the latter especially at the position of cell division. ZDOCK analysis showed that FliC could bind with serine/threonine protein kinase, membrane protein insertase YidC and redox membrane protein CydB. It was inferred that FliC interferes with cell division of B. nematocidal B16, therefore inhibiting its colonization of C. elegans intestines in vivo. The isolation of P. diazotrophicus as part of the gut microbiome of C. elegans not only provides interesting insights about the lifestyle of this nitrogen-fixing bacterium, but also reveals how the composition of the natural gut microbiota of nematodes can affect biological control efforts by protecting the host from its natural enemies.

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Caenorhabditis elegans lin-25: A Study of Its Role in Multiple Cell Fate Specification Events Involving Ras and the Identification and Characterization of Evolutionarily Conserved Domains

Genetics ◽

10.1093/genetics/156.3.1083 ◽

2000 ◽

Vol 156 (3) ◽

pp. 1083-1096

Author(s):

Lars Nilsson ◽

Teresa Tiensuu ◽

Simon Tuck

Keyword(s):

Caenorhabditis Elegans ◽

Cell Fate ◽

Nuclear Translocation ◽

Cell Fate Specification ◽

Sequence Comparisons ◽

Vulval Development ◽

Fate Specification ◽

C Elegans

Abstract Caenorhabditis elegans lin-25 functions downstream of let-60 ras in the genetic pathway for the induction of the 1° cell fate during vulval development and encodes a novel 130-kD protein. The biochemical activity of LIN-25 is presently unknown, but the protein appears to function together with SUR-2, whose human homologue binds to Mediator, a protein complex required for transcriptional regulation. We describe here experiments that indicate that, besides its role in vulval development, lin-25 also participates in the fate specification of a number of other cells in the worm that are known to require Ras-mediated signaling. We also describe the cloning of a lin-25 orthologue from C. briggsae. Sequence comparisons suggest that the gene is evolving relatively rapidly. By characterizing the molecular lesions associated with 10 lin-25 mutant alleles and by assaying in vivo the activity of mutants lin-25 generated in vitro, we have identified three domains within LIN-25 that are required for activity or stability. We have also identified a sequence that is required for efficient nuclear translocation. We discuss how lin-25 might act in cell fate specification in C. elegans within the context of models for lin-25 function in cell identity and cell signaling.

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Caenorhabditis elegans as an in vivo Model to Assess Amphetamine Tolerance

Brain Behavior and Evolution ◽

10.1159/000514858 ◽

2021 ◽

pp. 1-9

Author(s):

Dayana Torres Valladares ◽

Sirisha Kudumala ◽

Murad Hossain ◽

Lucia Carvelli

Keyword(s):

Caenorhabditis Elegans ◽

Molecular Mechanisms ◽

Drugs Of Abuse ◽

Genetic Model ◽

In Vivo Model ◽

C Elegans ◽

Hyperactivity Disorder ◽

In Vitro Data

Amphetamine is a potent psychostimulant also used to treat attention deficit/hyperactivity disorder and narcolepsy. In vivo and in vitro data have demonstrated that amphetamine increases the amount of extra synaptic dopamine by both inhibiting reuptake and promoting efflux of dopamine through the dopamine transporter. Previous studies have shown that chronic use of amphetamine causes tolerance to the drug. Thus, since the molecular mechanisms underlying tolerance to amphetamine are still unknown, an animal model to identify the neurochemical mechanisms associated with drug tolerance is greatly needed. Here we took advantage of a unique behavior caused by amphetamine in <i>Caenorhabditis elegans</i> to investigate whether this simple, but powerful, genetic model develops tolerance following repeated exposure to amphetamine. We found that at least 3 treatments with 0.5 mM amphetamine were necessary to see a reduction in the amphetamine-induced behavior and, thus, to promote tolerance. Moreover, we found that, after intervals of 60/90 minutes between treatments, animals were more likely to exhibit tolerance than animals that underwent 10-minute intervals between treatments. Taken together, our results show that <i>C. elegans</i> is a suitable system to study tolerance to drugs of abuse such as amphetamines.

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Transfer and tissue-specific accumulation of components in embryos of Caenorhabditis elegans and dolichura: in vivo analysis with a low-cost signal

Development ◽

10.1242/dev.114.2.317 ◽

1992 ◽

Vol 114 (2) ◽

pp. 317-330 ◽

Cited By ~ 4

Author(s):

O. Bossinger ◽

E. Schierenberg

Keyword(s):

Caenorhabditis Elegans ◽

Low Cost ◽

Free Living ◽

Tissue Specific ◽

C Elegans ◽

Specific Accumulation ◽

In Vivo Analysis

The pattern of autofluorescence in the two free-living namatodes Rhabditis dolichura and Caenorhabditis compared. In C. elegans, during later embryogenesis cells develop a typical bluish autofluorescence as illumination, while in Rh. dolichura a strong already present in the unfertilized egg. Using a new,

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Edible Flowers of Tagetes erecta L. as Functional Ingredients: Phenolic Composition, Antioxidant and Protective Effects on Caenorhabditis elegans

Nutrients ◽

10.3390/nu10122002 ◽

2018 ◽

Vol 10 (12) ◽

pp. 2002 ◽

Cited By ~ 7

Author(s):

Cristina Moliner ◽

Lillian Barros ◽

Maria Dias ◽

Víctor López ◽

Elisa Langa ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

In Vivo Model ◽

Tagetes Erecta ◽

Protective Effects ◽

Phenolic Composition ◽

C Elegans ◽

Amyloid Toxicity ◽

Phenolic Profiles ◽

Tagetes Erecta L

Tagetes erecta L. has long been consumed for culinary and medicinal purposes in different countries. The aim of this study was to explore the potential benefits from two cultivars of T. erecta related to its polyphenolic profile as well as antioxidant and anti-aging properties. The phenolic composition was analyzed by LC-DAD-ESI/MSn. Folin-Ciocalteu, DPPH·, and FRAP assays were performed in order to evaluate reducing antiradical properties. The neuroprotective potential was evaluated using the enzymes acetylcholinesterase and monoamine oxidase. Caenorhabditis elegans was used as an in vivo model to assess extract toxicity, antioxidant activity, delayed aging, and reduced β-amyloid toxicity. Both extracts showed similar phenolic profiles and bioactivities. The main polyphenols found were laricitin and its glycosides. No acute toxicity was detected for extracts in the C. elegans model. T. erecta flower extracts showed promising antioxidant and neuroprotective properties in the different tested models. Hence, these results may add some information supporting the possibilities of using these plants as functional foods and/or as nutraceutical ingredients.

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Genetic control of programmed cell death in the Caenorhabditis elegans hermaphrodite germline

Development ◽

10.1242/dev.126.5.1011 ◽

1999 ◽

Vol 126 (5) ◽

pp. 1011-1022 ◽

Cited By ~ 8

Author(s):

T.L. Gumienny ◽

E. Lambie ◽

E. Hartwieg ◽

H.R. Horvitz ◽

M.O. Hengartner

Keyword(s):

Cell Death ◽

Caenorhabditis Elegans ◽

Germ Cell ◽

Somatic Cell ◽

Cell Fate ◽

Germ Cells ◽

Mapk Pathway ◽

Apoptotic Cell ◽

C Elegans ◽

Pathway Activation

Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same apoptotic execution machinery (ced-3, ced-4 and ced-9) as the previously described 131 somatic cell deaths. However, this machinery is activated by a distinct pathway, as loss of egl-1 function, which inhibits somatic cell death, does not affect germ cell apoptosis. Germ cell death requires ras/MAPK pathway activation and is used to maintain germline homeostasis. We suggest that apoptosis eliminates excess germ cells that acted as nurse cells to provide cytoplasmic components to maturing oocytes.

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Identification of gmhA, a Yersinia pestis Gene Required for Flea Blockage, by Using a Caenorhabditis elegans Biofilm System

Infection and Immunity ◽

10.1128/iai.73.11.7236-7242.2005 ◽

2005 ◽

Vol 73 (11) ◽

pp. 7236-7242 ◽

Cited By ~ 55

Author(s):

Creg Darby ◽

Sandya L. Ananth ◽

Li Tan ◽

B. Joseph Hinnebusch

Keyword(s):

Caenorhabditis Elegans ◽

Yersinia Pestis ◽

Biofilm Formation ◽

Yersinia Pseudotuberculosis ◽

C Elegans ◽

Transposon Insertion ◽

Insertion Mutants ◽

Random Screening

ABSTRACT Yersinia pestis, the cause of bubonic plague, blocks feeding by its vector, the flea. Recent evidence indicates that blockage is mediated by an in vivo biofilm. Y. pestis and the closely related Yersinia pseudotuberculosis also make biofilms on the cuticle of the nematode Caenorhabditis elegans, which block this laboratory animal's feeding. Random screening of Y. pseudotuberculosis transposon insertion mutants with a C. elegans biofilm assay identified gmhA as a gene required for normal biofilms. gmhA encodes phosphoheptose isomerase, an enzyme required for synthesis of heptose, a conserved component of lipopolysaccharide and lipooligosaccharide. A Y. pestis gmhA mutant was constructed and was severely defective for C. elegans biofilm formation and for flea blockage but only moderately defective in an in vitro biofilm assay. These results validate use of the C. elegans biofilm system to identify genes and pathways involved in Y. pestis flea blockage.

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