tailieunhanh - Báo cáo y học: "Meiotic control of the APC/C: similarities & differences from mitosis"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Critical Care giúp cho các bạn có thêm kiến thức về ngành y học đề tài: Meiotic control of the APC/C: similarities & differences from mitosis. | 0 CELL DIVISION Cooper and Strich Cell Division 2011 6 16 http content 6 1 16 REVIEW Open Access Meiotic control of the APC C similarities differences from mitosis Katrina F Cooper and Randy Strich Abstract The anaphase promoting complex is a highly conserved E3 ligase complex that mediates the destruction of key regulatory proteins during both mitotic and meiotic divisions. In order to maintain ploidy this destruction must occur after the regulatory proteins have executed their function. Thus the regulation of APC C activity itself is critical for maintaining ploidy during all types of cell divisions. During mitotic cell division two conserved activator proteins called Cdc20 and Cdh1 are required for both APC C activation and substrate selection. However significantly less is known about how these proteins regulate APC C activity during the specialized meiotic nuclear divisions. In addition both budding yeast and flies utilize a third meiosis-specific activator. In Saccharomyces cerevisiae this meiosis-specific activator is called Ama1. This review summarizes our knowledge of how Cdc20 and Ama1 coordinate APC C activity to regulate the meiotic nuclear divisions in yeast. Meiosis and gametogenesis The proper segregation of chromosomes at meiosis I and II is essential for producing gametes with the correct haploid genome Figure 1 . During oogenesis meio-tic progression is arrested at the first or second division during development. Maturation of the oocytes or fertilization is required to relieve these blocks respectively. Spermatogenesis is a continuous process that occurs throughout most of the life of the male. Yeast sporulation possesses the hallmarks of mammalian meiosis and is similar to spermatogenesis in that the process does not exhibit programmed arrest points. In Saccharomyces cerevisiae entry into the meiotic program is dependent upon cell-type and environmental clues 1 . Following induction premeiotic DNA replication occurs followed by