A new family of adenylyl cyclase genes in the male germline of Drosophila melanogaster

We describe the cloning and characterization of a new gene family of adenyl yl cyclase related genes in Drosophila. The five adenylyl cyclase-like gene s that define this family are clearly distinct from previously known adenyl yl cyclases. One member forms a unique locus on chromosome 3 whereas the ot her four members form a tightly clustered, tandemly repeated array on chrom osome 2. The genes on chromosome 2 are transcribed in the male germline in a doublesex, dependent manner and are expressed in postmitotic, meiotic, an d early differentiating sperm. These genes therefore provide the first evid ence for a role for the cAMP signaling pathway in Drosophila spermatogenesi s. Expression from this locus is under the control of the always early, can nonball, meiosis arrest, and spermatocyte arrest genes that are required fo r the G(2)/M transition of meiosis I during spermatogenesis, implying a mec hanism for the coordination of differentiation and proliferation. Evidence is also provided for positive selection at the locus on chromosome 2 which suggests this gene family is actively evolving and may play a novel role in spermatogenesis.