MSI-1, a neural RNA-binding protein, is involved in male mating behaviour in Caenorhabditis elegans

Background: Neural RNA-binding proteins are thought to play important roles in neural development and the functional regulation of postmitotic neurone s by mediating post-transcriptional gene regulation. RNA-binding proteins b elonging to the Musashi family are highly expressed in the nervous system; however, their roles are poorly understood. Results: We identified a Caenorhabditis elegans Musashi homologue, MSI-1, w hose RNA-recognition motifs show extensive similarity to those of Drosphila and vertebrate Musashi proteins. We isolated a msi-1 mutant and found male s with this mutation to have a mating defect. C. elegans male mating behavi our includes a distinct series of steps: response to contact, backing, turn ing, vulva location, spicule insertion, and sperm transfer. msi-l is requir ed for the turning and vulva location steps. Like other Musashi family memb ers, MSI-1 is expressed specifically in neural cells, including male-specif ic neurones required for turning and vulva location. However, msi-1 was not expressed in proliferating neural progenitors in C. elegans, unlike the Mu sashi family genes in other systems. Conclusions: Our results suggest that msi-l is expressed specifically in po stmitotic neurones in C. elegans. msi-1 is required for full development of male mating behaviour, possibly through regulation of msi-1 expressing neu rones.