A FAMILY OF DROSOPHILA GENES ENCODING QUAKING-RELATED MAXI-KH DOMAINS

We recently identified a Drosophila gene, wings held out (who), that s pecifies a STAR (signal transduction and RNA activation) protein expre ssed within mesoderm and muscles. Genetic evidence suggests that WHO r egulates muscle development and function in response to steroid hormon e titer: who is related to the mouse quaking, gene, essential for embr yogenesis and neural myelination, and gld-1, a nematode tumor suppress or gene necessary for oocyte differentiation, both of which contain RN A binding ''maxi-KH'' domains presumed to link RNA metabolism to cell signaling. To initiate a broader study of Drosophila WHO-related prote ins we used degenerate primers encoding peptides unique to maxi-KH dom ains to amplify the corresponding genes. We recovered nine genes, all specifying single maxi-KH domain proteins having tripartite regions of similarity that extend over 200 amino acids. One is located within th e 54D chromosome subdivision, and one within 58C, while the remaining seven are within the 58E subdivision. At least foul of these STAR prot eins are expressed in a general manner, suggesting that maxi-KH domain s are employed widely in Drosophila.