title: Meiosis I in Xenopus oocytes is not error-prone despite lacking spindle assembly checkpoint.
abstract: The spindle assembly checkpoint, SAC, is a surveillance mechanism to control the onset of anaphase during cell division. SAC prevents anaphase initiation until all chromosome pairs have achieved bipolar attachment and aligned at the metaphase plate of the spindle. In doing so, SAC is thought to be the key mechanism to prevent chromosome nondisjunction in mitosis and meiosis. We have recently demonstrated that Xenopus oocyte meiosis lacks SAC control. This prompted the question of whether Xenopus oocyte meiosis is particularly error-prone. In this study, we have karyotyped a total of 313 Xenopus eggs following in vitro oocyte maturation. We found no hyperploid egg, out of 204 metaphase II eggs with countable chromosome spreads. Therefore, chromosome nondisjunction is very rare during Xenopus oocyte meiosis I, despite the lack of SAC.
authors.affiliation: State Key Laboratory of Reproductive Biology; Institute of Zoology; Chinese Academy of Sciences; Beijing, China; University of Chinese Academy of Sciences; Beijing, China; Ottawa Hospital Research Institute; The Ottawa Hospital - General Campus; Ottawa, Ontario, Canada.
authors.forename: Dandan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Ottawa Hospital Research Institute; The Ottawa Hospital - General Campus; Ottawa, Ontario, Canada.
authors.forename: Hua
authors.initials: H
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Reproductive Biology; Institute of Zoology; Chinese Academy of Sciences; Beijing, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Ottawa Hospital Research Institute; The Ottawa Hospital - General Campus; Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology, and Immunology and Department of Obstetrics and Gynecology; University of Ottawa; Ottawa, Ontario, Canada.
authors.forename: X Johné
authors.initials: XJ
authors.lastname: Liu
mesh_terms: D000818:Animals; D020090:Chromosome Segregation; D003603:Cytotoxins / Q000494:pharmacology; D005260:Female; D007621:Karyotyping; D059566:M Phase Cell Cycle Checkpoints; D008540:Meiosis; D015739:Nocodazole / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D003603:Cytotoxins; D015739:Nocodazole
keywords: Xenopusoocyte; aneuploidy; karyotyping; meiosis; spindle assembly checkpoint