The
fem-3 gene is required for specification of the male fate. In hermaphrodites, it specifies spermatogenesis and is contributed maternally to influence progeny sex; in males, it specifies male development in all tissues. Previously we have shown that
fem-3 RNA is present in adult hermaphrodites, but that it is absent from adult hermaphrodites that lack a germ line [either SS104
(bn2) or
glp-1(
q224) 1 (Rosenquist and Kimble, 1988). We interpret this to mean that
fem-3 RNA is limited to the germ line in hermaphrodites. We have now used SS104 and
glp-1 mutants to examine the presence of
fem-3 RNA in adult males with and without a germline. In contrast to hermaphrodites, we find that
fem-3 RNA is detectable in XO males whether or not they have a germline. We interpret this to mean that
fem-3 RNA is present in XO somatic tissues. To examine the molecular basis of the Hodgkin model in which the sex determination genes are proposed to act in a cascade of negative regulation (see below), we are in the process of testing double mutants for the presence of
fem-3 RNA in XX animals masculinized by a tra(lf) mutation or for the absence of
fem-3 RNA in XO animals feminized by a fem(lf), her(lf), or tra(gf) mutation. Preliminary data indicate that XX pseudomales of genotype
bn2;
tra-3(
e1107)(m-z-) do contain somatic
fem-3 RNA in the XX soma. In addition, we have shown by primer extension experiments that
fem-3 RNA is trans- spliced to the 22bp leader RNA described by Krause and Hirsh.