fog-1, a regulatory gene required for specification of spermatogenesis in the germ line of Caenorhabditis elegans.
In wild-type Caenorhabditis elegans, the XO male germ line makes only sperm and the XX hermaphrodite germ line makes sperm and then oocytes. In contrast, the germ line of either a male or a hermaphrodite carrying a mutation of the fog-1 (feminization of the germ line) locus is sexually transformed: cells that would normally make sperm differentiate as oocytes. However, the somatic tissues of fog-1 mutants remain unaffected. All fog-1 alleles identified confer the same phenotype. The fog-1 mutations appear to reduce fog-1 function, indicating that the wild-type fog-1 product is required for specification of a germ cell as a spermatocyte. Two lines of evidence indicate that a germ cell is determined for sex at about the same time that it enters meiosis. These include the fog-1 temperature sensitive period, which coincides in each sex with first entry into meiosis, and the phenotype of a fog-1; glp-1 double mutant. Experiments with double mutants show that fog-1 is epistatic to mutations in all other sex-determining genes tested. These results lead to the conclusion that fog-1 acts at the same level as the fem genes at the end of the sex determination pathway to specify germ cells as sperm.
Barton
M K
MK
Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706.
Kimble
J
J
D000483:Alleles; D000818:Animals; D002107:Caenorhabditis / Q000235:genetics* / Q000502:physiology; D002874:Chromosome Mapping; D004843:Epistasis, Genetic; D005260:Female; D005796:Genes; D005809:Genes, Regulator; D005838:Genotype; D008297:Male; D009154:Mutation; D009928:Organ Specificity / Q000235:genetics; D010641:Phenotype; D012732:Sex Determination Analysis; D013091:Spermatogenesis / Q000235:genetics; D013696:Temperature