Shonn Marion A, McCarroll Robert, Murray Andrew W
Department of Molecular and Cell Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Genes Dev. 2002 Jul 1;16(13):1659-71. doi: 10.1101/gad.975802.
In the absence of Spo13, budding yeast cells complete a single meiotic division during which sister chromatids often separate. We investigated the function of Spo13 by following chromosomes tagged with green fluorescent protein. The occurrence of a single division in spo13Delta homozygous diploids depends on the spindle checkpoint. Eliminating the checkpoint accelerates meiosis I in spo13Delta cells and allows them to undergo two divisions in which sister chromatids often separate in meiosis I and segregate randomly in meiosis II. Overexpression of Spo13 and the meiosis-specific cohesin Rec8 in mitotic cells prevents separation of sister chromatids despite destruction of Pds1 and activation of Esp1. This phenotype depends on the combined overexpression of both proteins and mimics one aspect of meiosis I chromosome behavior. Overexpressing the mitotic cohesin, Scc1/Mcd1, does not substitute for Rec8, suggesting that the combined actions of Spo13 and Rec8 are important for preventing sister centromere separation in meiosis I.
在缺乏Spo13的情况下，芽殖酵母细胞完成一次减数分裂，在此过程中姐妹染色单体常常分离。我们通过追踪标记有绿色荧光蛋白的染色体来研究Spo13的功能。spo13Δ纯合二倍体中单次分裂的发生取决于纺锤体检查点。消除该检查点会加速spo13Δ细胞中的减数分裂I，并使它们能够进行两次分裂，其中姐妹染色单体在减数分裂I中常常分离，在减数分裂II中随机分离。有丝分裂细胞中Spo13和减数分裂特异性黏连蛋白Rec8的过表达可防止姐妹染色单体分离，尽管Pds1被破坏且Esp1被激活。这种表型取决于两种蛋白质的联合过表达，并模拟了减数分裂I染色体行为的一个方面。过表达有丝分裂黏连蛋白Scc1/Mcd1不能替代Rec8，这表明Spo13和Rec8的联合作用对于防止减数分裂I中姐妹着丝粒分离很重要。
