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