Watanabe Yoshinori
Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi1-1-1, Tokyo 113-0032, Japan.
Curr Opin Cell Biol. 2005 Dec;17(6):590-5. doi: 10.1016/j.ceb.2005.10.003. Epub 2005 Oct 17.
A recently emerging protein family, shugoshin, plays a crucial role in the centromeric protection of cohesin, which is responsible for sister chromatid cohesion. This is especially important at the first meiotic division, where cohesin is cleaved by separase only along chromosome arms while the centromeric cohesin must be preserved. In vertebrate cells, arm cohesion is largely lost during prophase and prometaphase in order to facilitate sister chromatid resolution, whereas centromeric cohesion is preserved until the bipolar attachment of sister chromatids is established. Vertebrate shugoshin plays an essential role in protecting centromeric cohesin from prophase dissociation. In yeast, shugoshin also has a crucial role in sensing the loss of tension at kinetochores and in generating the spindle checkpoint signal.
最近出现的一个蛋白质家族——守护蛋白，在黏连蛋白的着丝粒保护中起着关键作用，黏连蛋白负责姐妹染色单体的黏连。这在第一次减数分裂中尤为重要，在该过程中，黏连蛋白仅在染色体臂上被分离酶切割，而着丝粒处的黏连蛋白必须得以保留。在脊椎动物细胞中，为了促进姐妹染色单体的分离，臂黏连在前期和前中期大部分消失，而着丝粒黏连则一直保留到姐妹染色单体的双极附着建立。脊椎动物的守护蛋白在保护着丝粒黏连蛋白以免在前期解离方面发挥着重要作用。在酵母中，守护蛋白在感知动粒处张力的丧失以及产生纺锤体检查点信号方面也起着关键作用。
