The elav gene is the prototype for a developmental regulator encoding a tissue-specific RNA-binding protein. The family of elav-like genes includes multiple members that are expressed in the nervous system at different times during development and also one that is expressed in all tissues. The elav-like proteins are proposed to function by binding to specific mRNAs and regulating their expression to control a developmental program. Consistent with this model, the overexpression of some elav-like genes results in an alteration in the developmental fates of some cells. Potential mRNA targets for these proteins have been identified along with functions in alternative RNA processing, cytoplasmic polyadenylation, and mRNA stability. This diversity of post-transcriptional regulatory events may be due to combinatorial interactions with other RNA-binding proteins and multiple effectors of RNA regulation.Copyright 1997 Academic Press Limited