she-1

she-1 (Cbr-SHE-1, "spermless hermaphrodites 1") is an F-box protein of Caenorhabditis briggsae required for spermatogenesis in XX hermaphrodites. The protein contains two F-box domains (residues ~24-69 and ~523-563), the protein-protein interaction module through which F-box proteins are recruited, via Skp, into SCF (Skp1/Cullin/F-box) E3 ubiquitin-ligase complexes where they serve as the substrate-recognition subunit that targets specific proteins for ubiquitin-dependent regulation. Loss-of-function and reduction-of-function mutations transform XX animals from self-fertile hermaphrodites into females that produce only oocytes (no spermatocytes), so that they are self-sterile but fertile when mated to males; the alleles are temperature-sensitive, and RNAi knock-down yields a strongly female-biased brood. she-1 acts in the germline sex-determination program genetically upstream of tra-2, as fog-2 does in C. elegans, and mutants fail to produce the FOG-3 protein that specifies the male (sperm) germ-cell fate; it thus promotes the brief burst of XX spermatogenesis that underlies self-fertile hermaphroditism. she-1 is a lineage-specific gene that arose from a recent gene duplication and has no clear one-to-one ortholog in C. elegans; it represents an independent recruitment of an F-box gene into the hermaphrodite sex-determination pathway, distinct from the unrelated F-box gene fog-2 used by C. elegans, exemplifying convergent evolution of self-fertile hermaphroditism in Caenorhabditis. Unlike FOG-2, SHE-1 does not bind GLD-1, so the two F-box proteins act through distinct activities. Its molecular targets, and whether it actually assembles into an SCF complex, have not been experimentally defined.