Abstract. The Drosophila

MEI-S332 protein has been shown to be required for the maintenance of sister-chromatid cohesion in male and female meiosis. The protein localizes to the centromeres during male meio-sis when the sister chromatids are attached, and it is no longer detectable after they separate. Drosophila mela-nogaster male meiosis is atypical in several respects, making it important to define MEI-S332 behavior dur-ing female meiosis, which better typifies meiosis in eu-karyotes. We find that MEI-S332 localizes to the cen-tromeres of prometaphase I chromosomes in oocytes, remaining there until it is delocalized at anaphase II. By using oocytes we were able to obtain sufficient material to investigate the fate of MEI-S332 after the metaphase II–anaphase II transition. The levels of MEI-S332 pro-tein are unchanged after the completion of meiosis, even when translation is blocked, suggesting that the protein dissociates from the centromeres but is not de-graded at the onset of anaphase II. Unexpectedly, MEI-S332 is present during embryogenesis, localizes onto the centromeres of mitotic chromosomes, and is delocalized from anaphase chromosomes. Thus, MEI-S332 associates with the centromeres of both meiotic and mitotic chromosomes and dissociates from them at anaphase