A 'checkpoint' role for MAD2 and BUB1 during meiosis in mouse oocytes.

摘要

Somatic cells have a "gatekeeper" that monitors the timing of mitosis to ensure the proper segregation and distribution of chromosomes to their daughter cells. During mitosis chromosomes must congress and align on the mitotic spindle equator in a precise fashion. If a chromosome is misaligned or lags behind during congression the "gatekeeper" is signaled and arrests division at metaphase until all the chromosomes have properly aligned. This "gatekeeper", one of several cell cycle checkpoints, consists of a large group of proteins. Two of these checkpoint proteins MAD2 and BUB1 localize to kinetochores of chromosomes in somatic cells at distinct stages of the cell cycle and are implicated in part for being responsible "gatekeepers" during the important metaphase to anaphase transition.;I hypothesized that certain identified molecular components of the mitosis checkpoint system, in particular MAD2 and BUB1, operate in a similar fashion during meiosis when maturing gametes segregate their chromosomes prior to fertilization.;Using various techniques, I have been able to identify localization patterns of these proteins prior to, during and following the first meiotic division in maturing mouse oocytes. In addition, I have shown the behavior of these proteins to be comparable to that in somatic cells. I will present a case for the role of these proteins during meiosis in mouse oocytes. Additional research on maturing oocytes of mouse and other species supports my data. Such information provides insight into a cellular mechanism responsible for the increase in aneuploidy in oocytes seen with advanced maternal age in females of many species, including Homo sapiens.