generates two transcripts, the larger of which encodes a small,secreted, cysteine-rich protein (HER-1A) required for normal sexdetermination in wild-type XO male animals, while being dispensable forsex determination in XX hermaphrodites; transcription of her-1
in XXanimals is repressed by SDC-2; HER-1A protein has two all-helicaldomains, with fourteen conserved cysteine residues forming sevendisulfide bonds, at least eight of which residues are critical forfunction in vivo; HER-1A has no known homologs except in other nematodes(e.g., Brugia malayi), and does not structurally resemble otherwell-known secreted proteins; HER-1A inhibits the receptor TRA-2A invivo, and binds it in vitro; HER-1A functions nonautonomously andrequires a signal sequence for biological activity; the her-1
gf)mutation alters a site in the her-1
promoter bound by SDC-2, partiallytransforms XX animals into phenotypic males, and requires sup-26
andsup-27 to do so.