A tissue-specific knock-out strategy reveals that lin-26 is required for the formation of the somatic gonad epithelium in Caenorhabditis elegans

The Caenorhabditis elegans LIN-26 protein is required to specify and/or maintain the fates of all non-neuronal ectodermal cells. Here we show that lin-26 is expressed until the somatic gonad primordium stage in all cells of the somatic gonad, except in distal tip cells, and later in all uterine cells. To determine if lin-26 functions in the somatic gonad, we have generated gonad-specific lin-26 alleles obtained by integration of lin-26 promoter deletion derivatives into a lin-26 null mutant background. In this way, we rescued the lethal phenotype imparted by lin-26 null mutations and uncovered a highly penetrant sterile phenotype. Specifically, the strongest of these new alleles was characterized by the absence of lin-26 expression in the somatic gonad, the presence of endomitotic oocytes, decreased germline proliferation, a protruding vulva and a less penetrant absence of gonad arms. Lineage analysis of mutant somatic gonads and examination of several markers expressed in the spermatheca, sheath cells, distal tip cells and the uterus, suggest that LIN-26 is required in sheath, spermatheca and uterine precursors, and in uterine cells. We conclude that lin-26 performs a similar function in the non-neuronal ectoderm and the somatic gonad, a mesoderm derivative, and we speculate that lin-26 is required to express epithelial characteristics.

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Genetic interactions among ADAMTS metalloproteases and basement membrane molecules in cell migration in Caenorhabditis elegans

PLoS ONE ◽

10.1371/journal.pone.0240571 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0240571

Author(s):

Ayaka Imanishi ◽

Yuma Aoki ◽

Masaki Kakehi ◽

Shunsuke Mori ◽

Tomomi Takano ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Basement Membrane ◽

Collagen Iv ◽

Wild Type ◽

Suppressor Mutations ◽

Genetic Suppressors ◽

Basement Membrane Protein ◽

Distal Tip Cells ◽

Tip Cells ◽

Shaped Pattern

During development of the Caenorhabditis elegans gonad, the gonadal leader cells, called distal tip cells (DTCs), migrate in a U-shaped pattern to form the U-shaped gonad arms. The ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family metalloproteases MIG-17 and GON-1 are required for correct DTC migration. Mutations in mig-17 result in misshapen gonads due to the misdirected DTC migration, and mutations in gon-1 result in shortened and swollen gonads due to the premature termination of DTC migration. Although the phenotypes shown by mig-17 and gon-1 mutants are very different from one another, mutations that result in amino acid substitutions in the same basement membrane protein genes, emb-9/collagen IV a1, let-2/collagen IV a2 and fbl-1/fibulin-1, were identified as genetic suppressors of mig-17 and gon-1 mutants. To understand the roles shared by these two proteases, we examined the effects of the mig-17 suppressors on gon-1 and the effects of the gon-1 suppressors and enhancers on mig-17 gonadal defects. Some of the emb-9, let-2 and fbl-1 mutations suppressed both mig-17 and gon-1, whereas others acted only on mig-17 or gon-1. These results suggest that mig-17 and gon-1 have their specific functions as well as functions commonly shared between them for gonad formation. The levels of collagen IV accumulation in the DTC basement membrane were significantly higher in the gon-1 mutants as compared with wild type and were reduced to the wild-type levels when combined with suppressor mutations, but not with enhancer mutations, suggesting that the ability to reduce collagen IV levels is important for gon-1 suppression.

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Mutations Affecting Symmetrical Migration of Distal Tip Cells in Caenorhabditis elegans

Genetics ◽

10.1093/genetics/152.3.985 ◽

1999 ◽

Vol 152 (3) ◽

pp. 985-997 ◽

Cited By ~ 2

Author(s):

Kiyoji Nishiwaki

Keyword(s):

Caenorhabditis Elegans ◽

Rotational Symmetry ◽

The Other ◽

Body Region ◽

Distal Tip Cells ◽

Complementation Groups ◽

Mutant Phenotypes ◽

Tip Cells ◽

Posterior Body Region ◽

Null Mutants

Abstract The rotational symmetry of the Caenorhabditis elegans gonad arms is generated by the symmetrical migration of two distal tip cells (DTCs), located on the anterior and posterior ends of the gonad primordium. Mutations that cause asymmetrical migration of the two DTCs were isolated. All seven mutations were recessive and assigned to six different complementation groups. vab-3(k121) and vab-3(k143) affected anterior DTC migration more frequently than posterior, although null mutants showed no bias. The other five mutations, mig-14(k124), mig-17(k113), mig-18(k140), mig-19(k142), and mig-20(k148), affected posterior DTC migration more frequently than anterior. These observations imply that the migration of each DTC is regulated differently. mig-14 and mig-19 also affected the migration of other cells in the posterior body region. Four distinct types of DTC migration abnormalities were defined on the basis of the mutant phenotypes. vab-3; mig-14 double mutants exhibited the types of DTC migration defects seen for vab-3 single mutants. Combination of mig-17 and mig-18 or mig-19, which are characterized by the same types of posterior DTC migration defects, exhibited strong enhancement of anterior DTC migration defects, suggesting that they affect the same or parallel pathways regulating anterior DTC migration.

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Caenorhabditis elegans triple null mutant lacking UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β1,2-N-acetylglucosaminyltransferase I

Biochemical Journal ◽

10.1042/bj20040793 ◽

2004 ◽

Vol 382 (3) ◽

pp. 995-1001 ◽

Cited By ~ 46

Author(s):

Shaoxian ZHU ◽

Andrew HANNEMAN ◽

Vernon N. REINHOLD ◽

Andrew M. SPENCE ◽

Harry SCHACHTER

Keyword(s):

Caenorhabditis Elegans ◽

Chromosome Number ◽

Null Mutant ◽

Wild Type ◽

Knock Out ◽

C Elegans ◽

In The Wild ◽

Wild Type Worm ◽

Type C ◽

Nematode Worm

We have previously reported, from the nematode worm Caenor-habditis elegans, three genes (gly-12, gly-13 and gly-14) encoding enzymically active UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β1,2-N-acetylglucosaminyltransferase I (GnT I), an enzyme essential for hybrid, paucimannose and complex N-glycan synthesis. We now describe a worm with null mutations in all three GnT I genes, gly-14 (III);gly-12 gly-13 (X) (III and X refer to the chromosome number). The triple-knock-out (TKO) worms have a normal phenotype, although they do not express GnT I activity and do not synthesize 31 paucimannose, complex and fucosylated oligomannose N-glycans present in the wild-type worm. The TKO worm has increased amounts of non-fucosylated oligomannose N-glycan structures, a finding consistent with the site of GnT I action. Five fucosylated oligomannose N-glycan structures were observed in TKO, but not wild-type, worms, indicating the presence of unusual GnT I-independent fucosyltransferases. It is concluded that wild-type C. elegans makes a large number of GnT I-dependent N-glycans that are not essential for normal worm development under laboratory conditions. The TKO worm may be more susceptible to mutations in other genes, thereby providing an approach for the identification of genes that interact with GnT I.

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Regulation of the UNC-5 netrin receptor initiates the first reorientation of migrating distal tip cells in Caenorhabditis elegans

Development ◽

10.1242/dev.127.3.585 ◽

2000 ◽

Vol 127 (3) ◽

pp. 585-594 ◽

Cited By ~ 4

Author(s):

M. Su ◽

D.C. Merz ◽

M.T. Killeen ◽

Y. Zhou ◽

H. Zheng ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Developmental Stage ◽

Phase 1 ◽

Critical Role ◽

The Body ◽

Dependent Manner ◽

C Elegans ◽

Guidance Cue ◽

Distal Tip Cells ◽

Tip Cells

Cell migrations play a critical role in animal development and organogenesis. Here, we describe a mechanism by which the migration behaviour of a particular cell type is regulated temporally and coordinated with over-all development of the organism. The hermaphrodite distal tip cells (DTCs) of Caenorhabditis elegans migrate along the body wall in three sequential phases distinguished by the orientation of their movements, which alternate between the anteroposterior and dorsoventral axes. The ventral-to-dorsal second migration phase requires the UNC-6 netrin guidance cue and its receptors UNC-5 and UNC-40, as well as additional, UNC-6-independent guidance systems. We provide evidence that the transcriptional upregulation of unc-5 in the DTCs is coincident with the initiation of the second migration phase, and that premature UNC-5 expression in these cells induces precocious turning in an UNC-6-dependent manner. The DAF-12 steroid hormone receptor, which regulates developmental stage transitions in C. elegans, is required for initiating the first DTC turn and for coincident unc-5 upregulation. We also present evidence for the existence of a mechanism that opposes or inhibits UNC-5 function during the longitudinal first migration phase and for a mechanism that facilitates UNC-5 function during turning. The facilitating mechanism presumably does not involve transcriptional regulation of unc-5 but may represent an inhibition of the phase 1 mechanism that opposes or inhibits UNC-5. These results, therefore, reveal the existence of two mechanisms that regulate the UNC-5 receptor that are critical for responsiveness to the UNC-6 netrin guidance cue and for linking the directional guidance of migrating distal tip cells to developmental stage advancements.

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The BED finger domain protein MIG-39 halts migration of distal tip cells in Caenorhabditis elegans

Developmental Biology ◽

10.1016/j.ydbio.2014.10.008 ◽

2015 ◽

Vol 397 (2) ◽

pp. 151-161 ◽

Cited By ~ 3

Author(s):

Tetsuhiro Kikuchi ◽

Yukimasa Shibata ◽

Hon-Song Kim ◽

Yukihiko Kubota ◽

Sawako Yoshina ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Distal Tip Cells ◽

Domain Protein ◽

Tip Cells

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A Limited and Diverse Set of Suppressor Mutations Restore Function to INX-8 Mutant Hemichannels in the Caenorhabditis elegans Somatic Gonad

Biomolecules ◽

10.3390/biom10121655 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1655

Author(s):

Todd Starich ◽

David Greenstein

Keyword(s):

Cell Proliferation ◽

Caenorhabditis Elegans ◽

Gap Junctions ◽

Germ Cell ◽

Structural Model ◽

Loss Of Function ◽

Suppressor Mutations ◽

Somatic Gonad ◽

Germline Proliferation ◽

Germ Cell Proliferation

In Caenorhabditis elegans, gap junctions couple cells of the somatic gonad with the germline to support germ cell proliferation and gametogenesis. A strong loss-of-function mutation (T239I) affects the second extracellular loop (EL2) of the somatic INX-8 hemichannel subunit. These mutant hemichannels form non-functional gap junctions with germline-expressed innexins. We conducted a genetic screen for suppressor mutations that restore germ cell proliferation in the T239I mutant background and isolated 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 channels that support germline proliferation but cause the demise of somatic sheath cells. Phenotypic analyses of three of the suppressors reveal an equivalency in the rescue of germline proliferation and comparable delays in gametogenesis but a graded rescue of fertility. The mutations described here may be useful for elucidating the biochemical pathways that produce the active biomolecules transiting through soma–germline gap junctions.

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The directed migration of gonadal distal tip cells in Caenorhabditis elegans requires NGAT-1, a ß1,4-N-acetylgalactosaminyltransferase enzyme

PLoS ONE ◽

10.1371/journal.pone.0183049 ◽

2017 ◽

Vol 12 (8) ◽

pp. e0183049 ◽

Cited By ~ 1

Author(s):

Joseph Veyhl ◽

Robert J. Dunn ◽

Wendy L. Johnston ◽

Alexa Bennett ◽

Lijia W. Zhang ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Directed Migration ◽

Distal Tip Cells ◽

Tip Cells

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Genetic interactions among ADAMTS metalloproteases and basement membrane molecules in cell migration in Caenorhabditis elegans

10.1101/2020.09.30.320093 ◽

2020 ◽

Author(s):

Ayaka Imanishi ◽

Yuma Aoki ◽

Masaki Kakehi ◽

Shunsuke Mori ◽

Tomomi Takano ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Basement Membrane ◽

Collagen Iv ◽

Wild Type ◽

Suppressor Mutations ◽

Genetic Suppressors ◽

Basement Membrane Protein ◽

Distal Tip Cells ◽

Tip Cells ◽

Shaped Pattern

AbstractDuring development of the Caenorhabditis elegans gonad, the gonadal leader cells, called distal tip cells (DTCs), migrate in a U-shaped pattern to form the U-shaped gonad arms. The ADAMTS (adisintegrin and metalloprotease with thrombospondin motifs) family metalloproteases MIG-17 and GON-1 are required for correct DTC migration. Mutations in mig-17 result in misshapen gonads due to the misdirected DTC migration, and mutations in gon-1 result in shortened and swollen gonads due to the premature termination of DTC migration. Although the phenotypes shown by mig-17 and gon-1 mutants are very different from one another, mutations that result in amino acid substitutions in the same basement membrane protein genes, emb-9/collagen IV a1, let-2/collagen IV a2 and fbl-1/fibulin-1, were identified as genetic suppressors of mig-17 and gon-1 mutants. To understand the roles shared by these two proteases, we examined the effects of the mig-17 suppressors on gon-1 and the effects of the gon-1 suppressors and enhancers on mig-17 gonadal defects. Some of the emb-9, let-2 and fbl-1 mutations suppressed both mig-17 and gon-1, whereas others acted only on mig-17 or gon-1. These results suggest that mig-17 and gon-1 have their specific functions as well as functions commonly shared between them for gonad formation. The levels of collagen IV accumulation in the DTC basement membrane were significantly higher in the gon-1 mutants as compared with wild type and were reduced to the wild-type levels when combined with suppressor mutations, but not with enhancer mutations, suggesting that the ability to reduce collagen IV levels is important for gon-1 suppression.

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Strategies for control of pattern formation in Caenorhabditis elegans

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1981.0159 ◽

1981 ◽

Vol 295 (1078) ◽

pp. 539-551 ◽

Cited By ~ 8

Keyword(s):

Caenorhabditis Elegans ◽

Pattern Formation ◽

Spatial Organization ◽

Germ Line ◽

Close Contact ◽

Distal Tip Cells ◽

Somatic Tissues ◽

Lineage Tree ◽

A Cell ◽

Tip Cells

In this paper, strategies for controlling pattern formation in Caenorhabditis elegans are reviewed. The somatic tissues of this small nematode develop, in large part, by invariant cell lineages, whereas the germ-line tissue arises primarily by a variable pattern of divisions. The spatial organization of the germ-line tissue depends on special regulatory cells, the distal tip cells, which appear to influence nearby germ cells to remain in mitosis. In somatic tissues, the problem of specifying that a cell in a particular position assumes a particular fate seems to be controlled by a number of different strategies. These include the production of non-equivalent cells in particular positions of the lineage tree, local interactions between apparently equivalent cells in close contact, and the influence of another special regulatory cell, the anchor cell, over certain neighbouring cells.

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Major sex-determining genes and the control of sexual dimorphism in Caenorhabditis elegans

Genome ◽

10.1139/g89-116 ◽

1989 ◽

Vol 31 (2) ◽

pp. 625-637 ◽

Cited By ~ 4

Author(s):

Jonathan Hodgkin ◽

Andrew D. Chisholm ◽

Michael M. Shen

Keyword(s):

Caenorhabditis Elegans ◽

Sex Determination ◽

X Chromosome ◽

Germ Line ◽

Cell Lineage ◽

Regulatory Genes ◽

Nematode Caenorhabditis Elegans ◽

X Chromosomes ◽

The Many ◽

Lineage Analysis

Sex determination in Caenorhabditis elegans involves a cascade of major regulatory genes connecting the primary sex determining signal, X chromosome dosage, to key switch genes, which in turn direct development along either male or female pathways. Animals with one X chromosome (XO) are male, while animals with two X chromosomes (XX) are hermaphrodite: hermaphrodite development occurs because the action of the regulatory genes is modified in the germ line so that both sperm and oocytes are made inside a completely female soma. The regulatory genes are being examined by both genetic and molecular means. We discuss how these major genes, in particular the last switch gene in the cascade, tra-1, might regulate the many different sex-specific events that occur during the development of the hermaphrodite and of the male.Key words: nematode, Caenorhabditis elegans, sex determination, sexual differentiation, cell lineage analysis.

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