Roles of Cyclin A and Cyclin B in Drosophila Female Meiosis

Cyclin Dependent Kinase 1 (CDK1) is a key mitotic regulator that associates with Cyclin proteins to form active Cyclin-CDK1 complexes. The mitotic roles of Cyclin-CDK1 complexes are well understood, but the regulation and function of the meiotic Cyclin-CDK1 complexes remain largely unsolved. This research project explored the roles of Cyclin A-CDK1 and Cyclin B-CDK1 in Drosophila female meiosis. This study found that constitutive activation of Cyclin A-CDK1 causes defects such as chromosome missegregation (meiosis I and II) and abnormal spindle assembly (meiosis II), implying that Cyclin A must be degraded before anaphase I and II. This study also found that Cyclin B-CDK1 is required for maintenance of the metaphase I arrest, proper chromosome segregation (meiosis I and II), proper spindle assembly (meiosis II), repression of DNA replication, and completion of meiosis. The findings of this study also suggest that Cyclin B -CDK1 may promote Cyclin A degradation during meiosis