Molecular cloning and transcript analysis of fem-3, a sex-determination gene in Caenorhabditis elegans.
The fem-3 gene is required for specification of the male fate in the nematode Caenorhabditis elegans: XO males need fem-3 for male differentiation in both soma and germ line; XX hermaphrodites need it for the production of sperm. We have cloned fem-3 by transposon tagging. Among eight spontaneous fem-3 mutations generated in a strain in which the transposable element Tc1 is mobile, six contain Tc1 insertions in a 2-kb region of the genome. From this region, we have identified three fem-3 transcripts. Two, 1.7 kb and 1.62 kb, are presented in embryos, and two, 1.62 kb and 1.55 kb, are present in L4s and adults. The fem-3 transcripts are not XO specific; however, in XX adult hermaphrodites, they appear to be limited to the germ line--a tissue involved in male development (both for spermatogenesis and for the maternal contribution of fem-3 to the embryo). The amount of fem-3 RNA in XO embryos is approximately sixfold greater than in XX embryos. The significance of this difference in specifying male development in XO but not in XX embryos is discussed.
Rosenquist
T A
TA
Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706.
Kimble
J
J
D000818:Animals; D002107:Caenorhabditis / Q000235:genetics* / Q000254:growth & development; D003001:Cloning, Molecular; D012734:Disorders of Sex Development; D005796:Genes; D007120:Immunochemistry; D008297:Male; D009154:Mutation; D012732:Sex Determination Analysis; D014158:Transcription, Genetic