Selective lineage specification by mab-19 during Caenorhabditis elegans male peripheral sense organ development.
The action of the gene mab-19 is required for specification of a subset of Caenorhabditis elegans male peripheral sense organ (ray) lineages. Two mab-19 alleles, isolated in screens for ray developmental mutations, resulted in males that lacked the three most posterior rays. Cell lineage alterations of male-specific divisions of the most posterior lateral hypodermal (seam) blast cell, T, resulted in the ray loss phenotype in mab-19 mutant animals. Postembryonic seam lineage defects were limited to male-specific T descendent cell divisions. Embryonic lethality resulted when either mab-19 mutation was placed over a chromosomal deficiency encompassing the mab-19 locus. The earliest detectable defect was aberrant hypodermal cell movements during morphogenesis. From these data, it is inferred that both mab-19 alleles described are hypomorphs, and further reduction of mab-19 function results in embryos that are unable to complete morphogenesis. Thus, mab-19 may play a larger role in developmental regulation of hypodermal cell fate, including sensory ray development in males. Body morphology mutations, passage through the dauer stage, and heat or CdCl2 treatment suppressed mab-19 male phenotypes. A model is presented in which all three types of suppression result in a physiological stress response, which in turn leads to correction of the mab-19 defect.
Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461.
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Sutherlin
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Emmons
D000483:Alleles; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics*; D005260:Female; D017238:Genes, Helminth; D006579:Heterozygote; D006358:Hot Temperature; D007814:Larva; D008297:Male; D008670:Metals; D009024:Morphogenesis; D009154:Mutation; D010375:Pedigree; D012679:Sense Organs / Q000196:embryology*
D008670:Metals