Cell Non-autonomous Function of daf-18/PTEN in the Somatic Gonad Coordinates Somatic Gonad and Germline Development in C. elegans Dauer Larvae

ABSTRACTBackgroundRNA interference (RNAi) related pathways are essential for germline development and fertility in metazoa and can contribute to inter-and trans-generational inheritance. In the nematode Caenorhabditis elegans environmental double-stranded RNA provided by feeding can lead to heritable changes in phenotype and gene expression. Notably, transmission efficiency differs between the male and female germline, yet the underlying mechanisms remain elusive.ResultsHere we use high-throughput sequencing of dissected gonads to quantify sex-specific endogenous piRNAs, miRNAs and siRNAs in the C. elegans germline and the somatic gonad. We identify genes with exceptionally high levels of 22G RNAs that are associated with low mRNA expression, a signature compatible with silencing. We further demonstrate that contrary to the hermaphrodite germline, the male germline, but not male soma, is resistant to environmental RNAi triggers provided by feeding. This sex-difference in silencing efficacy is associated with lower levels of gonadal RNAi amplification products. Moreover, this tissue-and sex-specific RNAi resistance is regulated by the germline, since mutant males with a feminized germline are RNAi sensitive.ConclusionThis study provides important sex-and tissue-specific expression data of miRNA, piRNA and siRNA as well as mechanistic insights into sex-differences of gene regulation in response to environmental cues.

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Faculty Opinions recommendation of Crosstalk between a nuclear receptor and beta-catenin signaling decides cell fates in the C. elegans somatic gonad.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1054022.505988 ◽

2006 ◽

Author(s):

Jane Hubbard

Keyword(s):

Nuclear Receptor ◽

Beta Catenin ◽

Cell Fates ◽

C Elegans ◽

Somatic Gonad

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UHPLC-IM-Q-ToFMS analysis of maradolipids, found exclusively in Caenorhabditis elegans dauer larvae

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03172-3 ◽

2021 ◽

Vol 413 (8) ◽

pp. 2091-2102

Author(s):

Michael Witting ◽

Ulrike Schmidt ◽

Hans-Joachim Knölker

Keyword(s):

Caenorhabditis Elegans ◽

Developmental Stage ◽

Ion Mobility ◽

Environmental Conditions ◽

Multidimensional Data ◽

Specific Class ◽

Lipid Profiling ◽

C Elegans ◽

Tandem Mass Spectrometric ◽

Dauer Larvae

AbstractLipid identification is one of the current bottlenecks in lipidomics and lipid profiling, especially for novel lipid classes, and requires multidimensional data for correct annotation. We used the combination of chromatographic and ion mobility separation together with data-independent acquisition (DIA) of tandem mass spectrometric data for the analysis of lipids in the biomedical model organism Caenorhabditis elegans. C. elegans reacts to harsh environmental conditions by interrupting its normal life cycle and entering an alternative developmental stage called dauer stage. Dauer larvae show distinct changes in metabolism and morphology to survive unfavorable environmental conditions and are able to survive for a long time without feeding. Only at this developmental stage, dauer larvae produce a specific class of glycolipids called maradolipids. We performed an analysis of maradolipids using ultrahigh performance liquid chromatography-ion mobility spectrometry-quadrupole-time of flight-mass spectrometry (UHPLC-IM-Q-ToFMS) using drift tube ion mobility to showcase how the integration of retention times, collisional cross sections, and DIA fragmentation data can be used for lipid identification. The obtained results show that combination of UHPLC and IM separation together with DIA represents a valuable tool for initial lipid identification. Using this analytical tool, a total of 45 marado- and lysomaradolipids have been putatively identified and 10 confirmed by authentic standards directly from C. elegans dauer larvae lipid extracts without the further need for further purification of glycolipids. Furthermore, we putatively identified two isomers of a lysomaradolipid not known so far. Graphical abstract

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Evolution of Sex Determination in Caenorhabditis: Unusually High Divergence of tra-1 and Its Functional Consequences

Genetics ◽

10.1093/genetics/144.2.587 ◽

1996 ◽

Vol 144 (2) ◽

pp. 587-595 ◽

Cited By ~ 5

Author(s):

Mario de Bono ◽

Jonathan Hodgkin

Keyword(s):

Sex Determination ◽

Germ Line ◽

Amino Acid Identity ◽

Evolution Of Sex ◽

Phenotypic Differences ◽

C Elegans ◽

Functional Studies ◽

Somatic Gonad ◽

Functional Consequences ◽

Significant Divergence

Abstract The tra-1 gene is a terminal regulator of somatic sex in Caenorhabditis elegans: high tra-1 activity elicits female development, low tra-1 activity elicits male development. To investigate the function and evolution of tra-1, we examined the tra-1 gene from the closely related nematode C. briggsae. Ce-tra-1 and Cb-tra-1 are unusually divergent. Each gene generates two transcripts, but only one of these is present in both species. This common transcript encodes TRA-1A, which shows only 44% amino acid identity between the species, a figure much lower than that for previously compared genes. A Cb-tra-1 transgene rescues many tissues of tra-1(nul1) mutants of C. elegans but not the somatic gonad or germ line. This transgene also causes nongonadal feminization of XO animals, indicating incorrect sexual regulation. Alignment of Ce-TRA-1A and Cb-TRA-1A defines several conserved regions likely to be important for tra-1 function. The phenotypic differences between Ce-tra-1(null) mutants rescued by Cb-tra-1 transgenes and wild-type C. elegans indicate significant divergence of regulatory regions. These molecular and functional studies suggest that evolution of sex determination in nematodes is rapid and genetically complex.

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lin-35/Rb and xnp-1/ATR-X function redundantly to control somatic gonad development in C. elegans

Developmental Biology ◽

10.1016/j.ydbio.2004.06.009 ◽

2004 ◽

Vol 273 (2) ◽

pp. 335-349 ◽

Cited By ~ 23

Author(s):

Aaron M. Bender ◽

Orion Wells ◽

David S. Fay

Keyword(s):

Gonad Development ◽

C Elegans ◽

Somatic Gonad

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hlh-12, a gene that is necessary and sufficient to promote migration of gonadal regulatory cells in C. elegans, evolved within the Caenorhabditis clade

Genetics ◽

10.1093/genetics/iyab127 ◽

2021 ◽

Author(s):

Hana E Littleford ◽

Karin Kiontke ◽

David H A Fitch ◽

Iva Greenwald

Keyword(s):

Ectopic Expression ◽

Morphological Diversity ◽

Nematode Species ◽

Bhlh Protein ◽

Vulval Development ◽

C Elegans ◽

Form And Function ◽

Somatic Gonad ◽

And Function ◽

Necessary And Sufficient

Abstract Specialized cells of the somatic gonad primordium of nematodes play important roles in the final form and function of the mature gonad. C. elegans hermaphrodites are somatic females that have a two-armed, U-shaped gonad that connects to the vulva at the midbody. The outgrowth of each gonad arm from the somatic gonad primordium is led by two female Distal Tip Cells (fDTC), while the Anchor Cell (AC) remains stationary and central to coordinate uterine and vulval development. The bHLH protein HLH-2 and its dimerization partners LIN-32 and HLH-12 had previously been shown to be required for fDTC specification. Here, we show that ectopic expression of both HLH-12 and LIN-32 in cells with AC potential transiently transforms them into fDTC-like cells. Furthermore, hlh-12 was known to be required for the fDTCs to sustain gonad arm outgrowth. Here, we show that ectopic expression of HLH-12 in the normally stationary AC causes displacement from its normal position, and that displacement likely results from activation of the leader program of fDTCs because it requires genes necessary for gonad arm outgrowth. Thus, HLH-12 is both necessary and sufficient to promote gonadal regulatory cell migration. As differences in female gonadal morphology of different nematode species reflect differences in the fate or migratory properties of the fDTCs or of the AC, we hypothesized that evolutionary changes in the expression of hlh-12 may underlie evolution of such morphological diversity. However, we were unable to identify an hlh-12 ortholog outside of Caenorhabditis. Instead, by performing a comprehensive phylogenetic analysis of all Class II bHLH proteins in multiple nematode species, we found that HLH-12 evolved within the Caenorhabditis clade, possibly by duplicative transposition of hlh-10. Our analysis suggests that control of gene regulatory hierarchies for gonadogenesis can be remarkably plastic during evolution without adverse phenotypic consequence.

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Mutations that Affect Channel Opening of Innexin Hemichannels in the C. elegans Gonad

10.20944/preprints202011.0151.v1 ◽

2020 ◽

Author(s):

Todd Starich ◽

David Greenstein

Keyword(s):

Cell Proliferation ◽

Gap Junctions ◽

Germ Cell ◽

Structural Model ◽

Loss Of Function ◽

C Elegans ◽

Somatic Gonad ◽

Channel Opening ◽

Germline Proliferation ◽

Germ Cell Proliferation

In C. elegans, gap junctions couple cells of the somatic gonad with the germline to support germ cell proliferation and gametogenesis. We previously characterized a strong loss-of-function mutation (T239I) affecting the second extracellular loop (EL2) of the somatic INX-8 hemichannel subunit. These mutant hemichannels form non-functional gap junctions with germline-expressed innexins. Here we describe the characterization of mutations that restore germ cell proliferation in the T239I EL2 mutant background. We recovered seven intragenic mutations located in diverse domains of INX-8 but not the EL domains. These second-site mutations compensate for the original channel defect to varying degrees, from nearly complete wild-type rescue, to partial rescue of germline proliferation. One suppressor mutation (E350K) supports the innexin cryo-EM structural model that the channel pore opening is surrounded by a cytoplasmic dome. Two suppressor mutations (S9L and I36N) may form leaky hemichannels that support germline proliferation but cause the demise of somatic sheath cells. Phenotypic analyses of three other suppressors reveal an equivalency in the rescue of germline proliferation and comparable delays in gametogenesis but a graded rescue of fertility. These latter mutations may be useful to probe interactions with the biochemical pathways that produce the molecules transiting through soma-germline gap junctions.

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A normally attractive cell interaction is repulsive in two C. elegans mesodermal cell migration mutants

Development ◽

10.1242/dev.113.3.797 ◽

1991 ◽

Vol 113 (3) ◽

pp. 797-803 ◽

Cited By ~ 4

Author(s):

M.J. Stern ◽

H.R. Horvitz

Keyword(s):

Cell Migration ◽

Caenorhabditis Elegans ◽

Premature Termination ◽

Cell Interaction ◽

Egg Laying ◽

Wild Type ◽

Mesodermal Cell ◽

C Elegans ◽

Somatic Gonad ◽

Sex Myoblasts

In wild-type Caenorhabditis elegans hermaphrodites, two bilaterally symmetric sex myoblasts (SMs) migrate anteriorly to flank the precise center of the gonad, where they divide to generate the muscles required for egg laying (J. E. Sulston and H. R. Horvitz (1977) Devl Biol. 56, 110–156). Although this migration is largely independent of the gonad, a signal from the gonad attracts the SMs to their precise final positions (J. H. Thomas, M. J. Stern and H. R. Horvitz (1990) Cell 62, 1041–1052). Here we show that mutations in either of two genes, egl-15 and egl-17, cause the premature termination of the migrations of the SMs. This incomplete migration is caused by the repulsion of the SMs by the same cells in the somatic gonad that are the source of the attractive signal in wild-type animals.

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The evolution of cell lineage in nematodes

Development ◽

10.1242/dev.1994.supplement.85 ◽

1994 ◽

Vol 1994 (Supplement) ◽

pp. 85-95

Author(s):

Ralf J. Sommer ◽

Lynn K. Carta ◽

Paul W. Sternberg

Keyword(s):

Cell Lineage ◽

Experimental System ◽

Nematode Species ◽

Cell Fates ◽

Equivalence Group ◽

Vulval Development ◽

C Elegans ◽

Somatic Gonad ◽

Vulval Precursor Cell ◽

P Cells

The invariant development of free-living nematodes combined with the extensive knowledge of Caenorhabditis elegans developmental biology provides an experimental system for an analysis of the evolution of developmental mechanisms. We have collected a number of new nematode species from soil samples. Most are easily cultured and their development can be analyzed at the level of individual cells using techniques standard to Caenorhabditis. So far, we have focused on differences in the development of the vulva among species of the families Rhabditidae and Panagrolaimidae. Preceding vulval development, twelve Pn cells migrate into the ventral cord and divide to produce posterior daughters [Pn.p cells] whose fates vary in a position specific manner [from P1.p anterior to P12.p posterior]. In C. elegans hermaphrodites, P(3-8).p are tripotent and form an equivalence group. These cells can express either of two vulval fates (1° or 2°) in response to a signal from the anchor cell of the somatic gonad, or a non-vulval fate (3°), resulting in a 3°-3°-2°-1°-2°-3° pattern of cell fates. Evolutionary differences in vulval development include the number of cells in the vulval equivalence group, the number of 1° cells, the number of progeny generated by each vulval precursor cell, and the position of VPCs before morphogenesis. Examples of three Rhabditidae genera have a posterior vulva in the position of P9-P11 ectoblasts. In Cruznema tripartitum, P(5-7).p form the vulva as in Caenorhabditis, but they migrate posteriorly before dividing. Induction occurs after the gonad grows posteriorly to the position of P(5-7).p cells. In two other species, Mesorhabditis sp. PS 1179 and Teratorhabditis palmarum, we have found changes in induction and competence with respect to their presumably more C. elegans-like ancestor. In Mesorhabditis, P(5-7).p form the vulva after migrating to a posterior position. However, the gonad is not required to specify the pattern of cell fates 3°-2°-1°-2°-3°. Moreover, the Pn.p cells are not equivalent in their potentials to form the vulva. A regulatory constraint in this family thus forces the same set of precursors to generate the vulva, rather than more appropriately positioned Pn.p cells.

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Regulation of Actin Dynamics in the C. elegans Somatic Gonad

Journal of Developmental Biology ◽

10.3390/jdb7010006 ◽

2019 ◽

Vol 7 (1) ◽

pp. 6 ◽

Cited By ~ 5

Author(s):

Charlotte Kelley ◽

Erin Cram

Keyword(s):

Reproductive System ◽

Cell Types ◽

Actin Dynamics ◽

Entry And Exit ◽

Cell Type ◽

C Elegans ◽

Type Study ◽

Somatic Gonad ◽

Uterus Contraction

The reproductive system of the hermaphroditic nematode C. elegans consists of a series of contractile cell types—including the gonadal sheath cells, the spermathecal cells and the spermatheca–uterine valve—that contract in a coordinated manner to regulate oocyte entry and exit of the fertilized embryo into the uterus. Contraction is driven by acto-myosin contraction and relies on the development and maintenance of specialized acto-myosin networks in each cell type. Study of this system has revealed insights into the regulation of acto-myosin network assembly and contractility in vivo.

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