Transcription regulatory networks in Caenorhabditis elegans

him-3 encodes a homolog of the S. cerevisiae HOP1 protein which is required for the formation of the synaptonemal complex during meiosis; him-3 is required for synapsis and chiasma formation during meiotic recombination and for chromosome segregation; him-3 mutants show a high frequency of males in the population as well as a high frequency of arrested embryos due to defects in X-chromosome segregation; HIM-3 localizes to the meiotic chromosome associating with both unsynapsed and synapsed chromosomes.

npp-10 is orthologous to the human gene NUCLEOPORIN, 98-KD (NUP98; OMIM:601021), which can promote leukemias (myelodysplastic syndromes, AML, or CML) when chromosomally rearranged.

her-1 generates two transcripts, the larger of which encodes a small, secreted, cysteine-rich protein (HER-1A) required for normal sex determination in wild-type XO male animals, while being dispensable for sex determination in XX hermaphrodites; transcription of her-1 in XX animals is repressed by SDC-2; HER-1A protein has two all-helical domains, with fourteen conserved cysteine residues forming seven disulfide bonds, at least eight of which residues are critical for function in vivo; HER-1A has no known homologs except in other nematodes (e.g., Brugia malayi), and does not structurally resemble other well-known secreted proteins; HER-1A inhibits the receptor TRA-2A in vivo, and binds it in vitro; HER-1A functions nonautonomously and requires a signal sequence for biological activity; the her-1(n695gf) mutation alters a site in the her-1 promoter bound by SDC-2, partially transforms XX animals into phenotypic males, and requires sup-26 and sup-27 to do so.