Integration of semaphorin-2A/MAB-20, ephrin-4, and UNC-129 TGF-beta signaling pathways regulates sorting of distinct sensory rays in C. elegans.
Semaphorins and ephrins are axon guidance cues. In C. elegans, semaphorin-2a/mab-20 and ephrin-4/efn-4/mab-26 also regulate cell sorting to form distinct rays in the male tail. Several erf (enhancer of ray fusion) mutations were identified in a mab-20 enhancer screen. Mutants of plexin-2 (plx-2) and unc-129, which encodes an axon guiding TGF-beta, were also found to be erfs. Genetic analyses show that plx-2 and mab-20 function in the same pathway, as expected if PLX-2 is a receptor for MAB-20. Surprisingly, MAB-20 also signals in a parallel pathway that requires efn-4. This signal utilizes a non-plexin receptor. The expression of plx-2, efn-4, and unc-129 in subsets of 3-cell sensory ray clusters likely mediates the ray-specific cell sorting functions of the ubiquitously expressed mab-20. We present a model for the integrated control of TGF-beta, semaphorin, and ephrin signaling in the sorting of cell clusters into distinct rays in the developing male tail.
Ikegami
Richard
R
Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, 600 University Avenue, Toronto M5G 1X5, Canada.
Zheng
Hong
H
Ong
Siew-Hwa
SH
Culotti
Joseph
J
D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016009:Chi-Square Distribution; D002874:Chromosome Mapping / Q000379:methods; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004742:Enhancer Elements, Genetic; D036385:Ephrin-A4 / Q000235:genetics / Q000502:physiology*; D036342:Ephrins / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D007150:Immunohistochemistry / Q000379:methods; D008164:Luminescent Proteins / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008958:Models, Molecular; D016254:Mutagenesis, Insertional / Q000379:methods; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012679:Sense Organs / Q000502:physiology*; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000502:physiology*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; C470369:EFN-4 protein, C elegans; D036385:Ephrin-A4; D036342:Ephrins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016212:Transforming Growth Factor beta; C113622:UNC-129 protein, C elegans; D029867:Xenopus Proteins; C405025:mab-20 protein, C elegans; D049452:Green Fluorescent Proteins; C438873:PlK2 protein, Xenopus; D017346:Protein Serine-Threonine Kinases