The dorsal-open group gene raw is required for restricted DJNK signaling during closure

During dorsal closure in Drosophila melanogaster, cells of the lateral epid ermis migrate over the amnioserosa to encase the embryo. At least three cla sses of dorsal-open group gene products are necessary for this morphogeneti c movement. Class I genes code for structural proteins that effect changes in epidermal cell shape and motility. Class II and III genes code for regul atory components of closure: Class II genes encode Drosophila Jun amino (N) -terminal kinase (DJNK) signaling molecules and Class III genes encode Deca pentaplegic-mediated signaling molecules. All characterized dorsal-open gro up gene products function in the epidermis. Here we report a molecular and genetic characterization of raw, a newly def ined member of the Class II dorsal-open group genes. We show that the novel protein encoded by raw is required for restriction of DJNK signaling to le ading edge epidermal cells as well as for proper development of the amniose rosa. Taken together, our results demonstrate a role for Raw in restriction of epidermal signaling during closure and suggest that this effect may be mediated via the amnioserosa.