Lack of response to unaligned chromosomes in mammalian female gametes

0380411 - ÚŽFG 2013 RIV US eng J - Journal Article
Šebestová, Jaroslava - Danylevska, Anna - Nováková, Lucia - Kubelka, Michal - Anger, Martin
Lack of response to unaligned chromosomes in mammalian female gametes.
Cell Cycle. Roč. 11, č. 16 (2012), s. 3011-3018. ISSN 1538-4101. E-ISSN 1551-4005
R&D Projects: GA ČR GA523/09/0743; GA ČR(CZ) GD204/09/H084; GA ČR GAP502/10/0944
Institutional research plan: CEZ:AV0Z50450515
Keywords : Anaphase * Aneuploidy * Cell cycle
Subject RIV: EB - Genetics ; Molecular Biology
Impact factor: 5.321, year: 2012

Chromosome segregation errors are highly frequent in mammalian female meiosis, and their incidence gradually increases with maternal age. The fate of aneuploid eggs is obviously dependent on the stringency of mechanisms for detecting unattached or repairing incorrectly attached kinetochores. In case of their failure, the newly formed embryo will inherit the impaired set of chromosomes, which will have severe consequences for its further development. Whether spindle assembly checkpoint (SAC) in oocytes is capable of arresting cell cycle progression in response to unaligned kinetochores was discussed for a long time. It is known that abolishing SAC increases frequency of chromosome segregation errors and causes precocious entry into anaphase; SAC, therefore, seems to be essential for normal chromosome segregation in meiosis I. However, it was also reported that for anaphase-promoting complex (APC) activation, which is a prerequisite for entering anaphase; alignment of only a critical mass of kinetochores on equatorial plane is sufficient. This indicates that the function of SAC and of cooperating chromosome attachment correction mechanisms in oocytes is different from somatic cells. To analyze this phenomenon, we used live cell confocal microscopy to monitor chromosome movements, spindle formation, APC activation and polar body extrusion (PBE) simultaneously in individual oocytes at various time points during first meiotic division. Our results, using oocytes from aged animals and interspecific crosses, demonstrate that multiple unaligned kinetochores and severe congression defects are tolerated at the metaphase to anaphase transition, although such cells retain sensitivity to nocodazole...
Permanent Link: http://hdl.handle.net/11104/0211126