The long term objective of this project is to understand the regulation of meiosis. Meiosis and mitosis are highly conserved processes. The central controller of mitotic and meiotic cell division is composed of a protein kinase subunit, cdc2 and regulatory subunit, cyclin. Homologs of these proteins are thought to regulate all cell divisions in eukaryotes. Other levels of cell division control remain to be identified. This project aims to use Drosophila spermatogenesis as a model system for the study of meiosis. Two genes previously shown to be required for entry into meiosis and male fertility in Drosophila spermatogenesis are boule and pelota.. To characterize the roles of boule and pelota in meiotic regulation, genetic and biochemical experiments will be carried out. The specific aims of this project are to 1) order the time of pelota and boule activity relative to known regulators of G2/M transition in cell division, 2) determine protein expression pattern and subcellular localization of Pelota and Boule, 3) identify targets of Boule and Pelota RNA binding activity, and 4) determine if the human gene Deleted in Azoospermia can replace boule in Drosophila spermatogenesis. This study seeks to identify and characterize central regulators of meiosis. In addition, one of these genes, boule, shares considerable sequence homology a human gene (DAZ) proposed to be required for male fertility, thus characterization of boule may be aid in the understanding of a major cause of infertility in men. This line of experimentation should not only provide insight into the basic mechanisms regulating meiotic cell divisions, but also be applicable to the investigation and treatment of male fertility and contraception.