Novel Caenorhabditis elegans unc-119 axon outgrowth defects correlate with behavioral phenotypes that are partially rescued by nonneural unc-119.
UNC-119 function is necessary for the correct development of the Caenorhabditis elegans nervous system. Worms mutant for unc-119 exhibit nervous system structural defects, including supernumerary axon branches, defasciculated nerve fibers, and choice point errors. Axons of both mechanosensory (ALM) and chemo- sensory (ASI) neurons have elongation defects within the nerve ring. Expressing unc-119 cDNA in mechanosensory neurons rescues the elongation defect of ALM axons, but expression in ASI neurons does not rescue ASI axon elongation defects. Neither gross movement nor dauer larva formation defects are rescued in either case. However, expressing a construct including introns under the control of the same promoters results in substantial rescue of phenotypic defects. In these cases reporter expression expands to tissues outside those specified by the promoter, notably into head muscles. Surprisingly, expressing an unc-119 cDNA construct under the control of a muscle-specific promoter fully rescues the dauer formation defect and substantially rescues movement. Thus, although UNC-119 normally acts in a cell-autonomous fashion, the cell-nonautonomous rescue of neural function suggests that it either acts at the cell surface or that it can be transported into the cell from the extracellular environment and play its normal role.
Materi
Wayne
W
Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
Pilgrim
David
D
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D001522:Behavior, Animal; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D005091:Exons; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D007438:Introns; D009132:Muscles / Q000294:innervation; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009475:Neurons, Afferent / Q000166:cytology*; D010641:Phenotype
D029742:Caenorhabditis elegans Proteins; D009419:Nerve Tissue Proteins; C098176:UNC-119 protein, C elegans; D049452:Green Fluorescent Proteins