The Drosophila Cystoblast Differentiation Factor, benign gonial cell neoplasm, Is Related to DExH-box Proteins and Interacts Genetically With bag-of-marbles

摘要

Selection of asymmetric cell fates can involve both intrinsic and extrinsic factors. Previously we have identified the bag-of-marbles ( bam ) gene as an intrinsic factor for cystoblast fate in Drosophila germline cells and shown that it requires active product from the benign gonial cell neoplasm ( bgcn ) gene. Here we present the cloning and characterization of bgcn. The predicted Bgcn protein is related to the DExH-box family of RNA-dependent helicases but lacks critical residues for ATPase and helicase functions. Expression of the bgcn gene is extremely limited in ovaries but, significantly, bgcn mRNA is expressed in a very limited number of germline cells, including the stem cells. Also, mutations in bgcn dominantly enhance a bam mutant phenotype, further corroborating the interdependence of these two genes' functions. On the basis of known functions of DExH-box proteins, we propose that Bgcn and Bam may be involved in regulating translational events that are necessary for activation of the cystoblast differentiation program.