Molecular characterization of the her-1 gene suggests a direct role in cell signaling during Caenorhabditis elegans sex determination.

We have characterized two transcripts from the male-determining her-1 locus in Caenorhabditis elegans. The larger transcript, which appears more important for male development, is predicted to encode a novel 175-amino-acid, cysteine-rich polypeptide with an apparent amino-terminal signal sequence and potential cleavage and glycosylation sites. Expression of a full-length cDNA construct for the larger transcript driven by a body-wall-myosin promoter causes extensive masculinization of all sexually dimorphic tissues in XX (normally hermaphrodite) animals. This activity is dependent on the presence of the her-1 signal sequence or a substitute synthetic signal sequence in the encoded polypeptide. These results suggest that a secreted product of the her-1 gene dictates male development.