[
Cell,
2005]
Biological rhythms with periods of less than a day are physiologically important but poorly understood. In this issue of Cell, Norman, Maricq, and colleagues (Norman et al., 2005) show that VAV-1, a guanine nucleotide exchange factor for Rho-family GTPases, is necessary for three rhythmic behaviors in the nematode Caenorhabditis elegans: feeding, defecation, and ovulation.
[
Genes Dev,
2002]
The CM domain is a cysteine-rich DNA-binding motif first recognized in proteins encoded by the Drosophila set determination gene doublesex (Erdman and Burtis 1993; Zhu et al. 2000). As the name doublesex (dsx) suggests, this gene has functions in both sexes: Its transcripts undergo sex-specific alternative splicing, so that it can encode either a male-specific isoform, DSX(M), or a female-specific isoform, DSX(F) (Baker and Wolfner 1988; Burtis and Baker 1989). These proteins have the same N-terminal DNA-binding domain, but different C termini that confer different regulatory properties on the two forms. The expression of DSX(M) directs male development, and the expression of DSX(F) directs female development, throughout most of the somatic tissues of the fruit fly.