Maintenance of cohesin at centromeres after meiosis I in budding yeast requires a kinetochore-associated protein related to MEI-S332
Maintenance of cohesin at centromeres after meiosis I in budding yeast requires a kinetochore-associated protein related to MEI-S332
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DOI：
10.1016/j.cub.2004.03.001
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发表时间：
2004-04-06
期刊：
影响因子：
9.2
通讯作者：
Nasmyth, K
中科院分区：
文献类型：
--
作者：
Katis, VL;Galova, M;Nasmyth, K
背景：减数分裂期间染色体数目减半取决于三个因素。首先，同源物必须配对和重组。其次，姐妹着丝粒必须附着在从同一纺锤体极发出的微管上，这确保了同源的母本和父本对可以被拉向相反的方向（称为同源双定向）。第三，姐妹着丝粒之间的凝聚力必须坚持后，第一次减数分裂，使他们的双定向在second.Results：屏幕中进行的裂殖酵母，以确定减数分裂染色体分离错误的突变体已经确定了一个保守的蛋白质称为Sgo 1，需要保持姐妹染色单体凝聚力后，第一次减数分裂。本文描述了芽殖酵母S.酿酒酵母（Sc），它不仅有减数分裂，而且有丝分裂染色体分离功能。Sc SGO 1的缺失不仅导致减数分裂I时频繁的同源不分离，而且导致减数分裂II时姐妹着丝粒的随机分离。第一次减数分裂后，着丝粒的减数分裂凝聚力不能持续，姐妹着丝粒经常过早分离。SGO 1是一个kinetochore相关的蛋白质，其丰度下降，在后期I，但尽管如此，坚持染色质，直到后期II。结论：发现SGO 1是本地化的着丝粒在第一次分裂的时候，这表明它可能发挥直接作用，防止去除着丝粒粘连蛋白。在序列组成，染色体位置，和突变体表型的sgo 1突变体在两个遥远的酵母与MEI-S332在果蝇的相似性表明，这些蛋白质定义了一个orthopathic家族保守的真核细胞谱系。
Background: The halving of chromosome number that occurs during meiosis depends on three factors. First, homologs must pair and recombine. Second, sister centromeres must attach to microtubules that emanate from the same spindle pole, which ensures that homologous maternal and paternal pairs can be pulled in opposite directions (called homolog biorientation). Third, cohesion between sister centromeres must persist after the first meiotic division to enable their biorientation at the second.Results: A screen performed in fission yeast to identify meiotic chromosome missegregation mutants has identified a conserved protein called Sgo1 that is required to maintain sister chromatid cohesion after the first meiotic division. We describe here an orthologous protein in the budding yeast S. cerevisiae (Sc), which has not only meiotic but also mitotic chromosome segregation functions. Deletion of Sc SGO1 not only causes frequent homolog nondisjunction at meiosis I but also random segregation of sister centromeres at meiosis II. Meiotic cohesion fails to persist at centromeres after the first meiotic division, and sister centromeres frequently separate precociously. Sgo1 is a kinetochore-associated protein whose abundance declines at anaphase I but, nevertheless, persists on chromatin until anaphase II.Conclusions: The finding that Sgo1 is localized to the centromere at the time of the first division suggests that it may play a direct role in preventing the removal of centromeric cohesin. The similarity in sequence composition, chromosomal location, and mutant phenotypes of sgo1 mutants in two distant yeasts with that of MEI-S332 in Drosophila suggests that these proteins define an orthologous family conserved in most eukaryotic lineages.