mab-20 encodes Semaphorin-2a and is required to prevent ectopic cell contacts during epidermal morphogenesis in Caenorhabditis elegans

Development ◽  
2000 ◽  
Vol 127 (4) ◽  
pp. 755-767 ◽  
Author(s):  
P.J. Roy ◽  
H. Zheng ◽  
C.E. Warren ◽  
J.G. Culotti
Keyword(s):  
Axon Guidance ◽  
Body Shape ◽  
Low Frequency ◽  
Transmembrane Proteins ◽  
Phenotypic Traits ◽  
Null Mutant ◽  
C Elegans ◽  
Epidermal Morphogenesis ◽  
Adhesive Contacts ◽  
Sensory Rays

The Semaphorins are a family of secreted and transmembrane proteins known to elicit growth cone repulsion and collapse. We made and characterized a putative null mutant of the C. elegans gene semaphorin-2a (Ce-sema-2a). This mutant failed to complement mutants of mab-20 (Baird, S. E., Fitch, D. H., Kassem, I. A. A. and Emmons, S. W. (1991) Development 113, 515–526). In addition to low-frequency axon guidance errors, mab-20 mutants have unexpected defects in epidermal morphogenesis. Errant epidermal cell migrations affect epidermal enclosure of the embryo, body shape and sensory rays of the male tail. These phenotypic traits are explained by the formation of inappropriate contacts between cells of similar type and suggest that Ce-Sema-2a may normally prevent formation or stabilization of ectopic adhesive contacts between these cells.

Caenorhabditis elegansPlexinA, PLX-1, interacts with transmembrane semaphorins and regulates epidermal morphogenesis

Development ◽  
2002 ◽  
Vol 129 (9) ◽  
pp. 2053-2063 ◽  
Author(s):  
Takashi Fujii ◽  
Fumi Nakao ◽  
Yukimasa Shibata ◽  
Go Shioi ◽  
Eiji Kodama ◽  
...  
Keyword(s):  
Rna Interference ◽  
Morphological Changes ◽  
Expression System ◽  
Transmembrane Proteins ◽  
Axonal Guidance ◽  
Heterologous Expression System ◽  
C Elegans ◽  
Morphological Defects ◽  
Epidermal Morphogenesis ◽  
Null Mutants

The plexin family transmembrane proteins are putative receptors for semaphorins, which are implicated in the morphogenesis of animal embryos, including axonal guidance. We have generated and characterized putative null mutants of the C. elegans plexinA gene, plx-1. plx-1 mutants exhibited morphological defects: displacement of ray 1 and discontinuous alae. The epidermal precursors for the affected organs were aberrantly arranged in the mutants, and a plx-1::gfp transgene was expressed in these epidermal precursor cells as they underwent dynamic morphological changes. Suppression of C. elegans transmembrane semaphorins, Ce-Sema-1a and Ce-Sema-1b, by RNA interference caused a displacement of ray 1 similar to that of plx-1 mutants, whereas mutants for the Ce-Sema-2a/mab-20 gene, which encodes a secreted-type semaphorin, exhibited phenotypes distinct from those of plx-1 mutants. A heterologous expression system showed that Ce-Sema-1a, but not Ce-Sema-2a, physically bound to PLX-1. Our results indicate that PLX-1 functions as a receptor for transmembrane-type semaphorins, and, though Ce-Sema-2a and PLX-1 both play roles in the regulation of cellular morphology during epidermal morphogenesis, they function rather independently.

Semaphorin 1a and semaphorin 1b are required for correct epidermal cell positioning and adhesion during morphogenesis in C. elegans

Development ◽  
2002 ◽  
Vol 129 (9) ◽  
pp. 2065-2078
Author(s):  
Val E. Ginzburg ◽  
Peter J. Roy ◽  
Joseph G. Culotti
Keyword(s):  
Axon Guidance ◽  
Transmembrane Proteins ◽  
Precursor Cell ◽  
Deletion Mutants ◽  
Normal Position ◽  
C Elegans ◽  
Seam Cell ◽  
Ray Cells ◽  
Cell Positioning ◽  
Anterior Posterior

The semaphorin family comprises secreted and transmembrane proteins involved in axon guidance and cell migration. We have isolated and characterized deletion mutants of C. elegans semaphorin 1a (Ce-sema-1a or smp-1) and semaphorin 1b (Ce-sema-1b or smp-2) genes. Both mutants exhibit defects in epidermal functions. For example, the R1.a-derived ray precursor cells frequently fail to change anterior/posterior positions completely relative to their sister tail lateral epidermal precursor cell R1.p, causing ray 1 to be formed anterior to its normal position next to ray 2. The ray cells, which normally separate from the lateral tail seam cell (SET) at the end of L4 stage, remains connected to the SET cell even in adult mutant males. The ray 1 defects are partially penetrant in each single Ce-sema-1 mutant at 20°C, but are greatly enhanced in Ce-sema-1 double mutants, suggesting that Ce-Sema-1a and Ce-Sema-1b function in parallel to regulate ray 1 position. Both mutants also have defects in other aspects of epidermal functions, including head and tail epidermal morphogenesis and touch cell axon migration, whereas, smp-1 mutants alone have defects in defecation and brood size. A feature of smp-1 mutants that is shared with mutants of mab-20 (which encodes Sema-2a) is the abnormal perdurance of contacts between epidermal cells.

A Cuticle Collagen Encoded by the lon-3 Gene May Be a Target of TGF-β Signaling in Determining Caenorhabditis elegans Body Shape

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1631-1639
Author(s):  
Yo Suzuki ◽  
Gail A Morris ◽  
Min Han ◽  
William B Wood
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Shape ◽  
Small Body ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Cellular Mechanisms ◽  
C Elegans ◽  
Gene Expression Analyses ◽  
Dose Dependent

Abstract The signaling pathway initiated by the TGF-β family member DBL-1 in Caenorhabditis elegans controls body shape in a dose-dependent manner. Loss-of-function (lf) mutations in the dbl-1 gene cause a short, small body (Sma phenotype), whereas overexpression of dbl-1 causes a long body (Lon phenotype). To understand the cellular mechanisms underlying these phenotypes, we have isolated suppressors of the Sma phenotype resulting from a dbl-1(lf) mutation. Two of these suppressors are mutations in the lon-3 gene, of which four additional alleles are known. We show that lon-3 encodes a collagen that is a component of the C. elegans cuticle. Genetic and reporter-gene expression analyses suggest that lon-3 is involved in determination of body shape and is post-transcriptionally regulated by the dbl-1 pathway. These results support the possibility that TGF-β signaling controls C. elegans body shape by regulating cuticle composition.

Identification Of A Novel Gene Altered In The RQ1 Mutant Strain Affecting Motor Axon Migration In Caenorhabditis Elegans

2021 ◽  
Author(s):  
Haider Z. Naqvi
Keyword(s):  
Caenorhabditis Elegans ◽  
Axon Guidance ◽  
Motor Neurons ◽  
Genetic Background ◽  
Germ Line ◽  
Strong Indication ◽  
Wild Type ◽  
C Elegans ◽  
Novel Gene ◽  
Mutation Region

Novel genetic enhancer screens were conducted targeting mutants involved in the guidance of axons of the DA and DB classes of motor neurons in C. elegans. These mutations are expected in genes that function in parallel to the unc-g/Netrin pathway. The screen was conducted in an unc-5(e53) genetic background and enhancers of the axon guidance defects caused by the absence of UNC-5 were identified. Three mutants were previously identified in the screen called rq1, rq2 and rq3 and two additional mutants called H2-4 and M1-3, were isolated in this study. In order to identify the gene affected by the rq1 mutation, wild-type copies of genes in the mapped rq1 mutation region were injected into the mutants to rescue the phenotypic defects. This is a strong indication that the gene of interest is a novel gene called H04D03.1. Promising results indicate that the H04D03.1 protein also works in germ-line apoptosis.

scholarly journals Three C. elegans Rac proteins and several alternative Rac regulators control axon guidance, cell migration and apoptotic cell phagocytosis

Development ◽  
2001 ◽  
Vol 128 (22) ◽  
pp. 4475-4488 ◽  
Author(s):  
Erik A. Lundquist ◽  
Peter W. Reddien ◽  
Erika Hartwieg ◽  
H. Robert Horvitz ◽  
Cornelia I. Bargmann
Keyword(s):  
Cell Migration ◽  
Axon Guidance ◽  
Apoptotic Cell ◽  
Regulatory Proteins ◽  
Axon Pathfinding ◽  
C Elegans ◽  
Cell Corpse ◽  
And Function ◽  
Redundant Functions ◽  
Caenorhabditis Elegans Genome

The Caenorhabditis elegans genome contains three rac-like genes, ced-10, mig-2, and rac-2. We report that ced-10, mig-2 and rac-2 act redundantly in axon pathfinding: inactivating one gene had little effect, but inactivating two or more genes perturbed both axon outgrowth and guidance. mig-2 and ced-10 also have redundant functions in some cell migrations. By contrast, ced-10 is uniquely required for cell-corpse phagocytosis, and mig-2 and rac-2 have only subtle roles in this process. Rac activators are also used differentially. The UNC-73 Trio Rac GTP exchange factor affected all Rac pathways in axon pathfinding and cell migration but did not affect cell-corpse phagocytosis. CED-5 DOCK180, which acts with CED-10 Rac in cell-corpse phagocytosis, acted with MIG-2 but not CED-10 in axon pathfinding. Thus, distinct regulatory proteins modulate Rac activation and function in different developmental processes.

scholarly journals TRPV channel OCR-2 is distributed along C. elegans chemosensory cilia by diffusion in a local interplay with intraflagellar transport

2020 ◽  
Author(s):  
Jaap van Krugten ◽  
Noémie Danné ◽  
Erwin J.G. Peterman
Keyword(s):  
Single Molecule ◽  
Transmembrane Proteins ◽  
Intraflagellar Transport ◽  
Single Molecule Tracking ◽  
C Elegans ◽  
Normal Diffusion ◽  
Cellular Signal ◽  
Underlying Mechanisms ◽  
And Function

AbstractSensing and reacting to the environment is essential for survival and procreation of most organisms. Caenorhabditis elegans senses soluble chemicals with transmembrane proteins (TPs) in the cilia of its chemosensory neurons. Development, maintenance and function of these cilia relies on intraflagellar transport (IFT), in which motor proteins transport cargo, including sensory TPs, back and forth along the ciliary axoneme. Here we use live fluorescence imaging to show that IFT machinery and the sensory TP OCR-2 reversibly redistribute along the cilium after exposure to repellant chemicals. To elucidate the underlying mechanisms, we performed single-molecule tracking experiments and found that OCR-2 distribution depends on an intricate interplay between IFT-driven transport, normal diffusion and subdiffusion that depends on the specific location in the cilium. These insights in the role of IFT on the dynamics of cellular signal transduction contribute to a deeper understanding of the regulation of sensory TPs and chemosensing.

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