Kiburz Brendan M, Reynolds David B, Megee Paul C, Marston Adele L, Lee Brian H, Lee Tong Ihn, Levine Stuart S, Young Richard A, Amon Angelika
Center for Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, 02139, USA.
Genes Dev. 2005 Dec 15;19(24):3017-30. doi: 10.1101/gad.1373005.
The stepwise loss of cohesins, the complexes that hold sister chromatids together, is required for faithful meiotic chromosome segregation. Cohesins are removed from chromosome arms during meiosis I but are maintained around centromeres until meiosis II. Here we show that Sgo1, a protein required for protecting centromeric cohesins from removal during meiosis I, localizes to cohesin-associated regions (CARs) at the centromere and the 50-kb region surrounding it. Establishment of this Sgo1-binding domain requires the 120-base-pair (bp) core centromere, the kinetochore component Bub1, and the meiosis-specific factor Spo13. Interestingly, cohesins and the kinetochore proteins Iml3 and Chl4 are necessary for Sgo1 to associate with pericentric regions but less so for Sgo1 to associate with the core centromeric regions. Finally, we show that the 50-kb Sgo1-binding domain is the chromosomal region where cohesins are protected from removal during meiosis I. Our results identify the portions of chromosomes where cohesins are protected from removal during meiosis I and show that kinetochore components and cohesins themselves are required to establish this cohesin protective domain.
连接姐妹染色单体的黏连蛋白复合物逐步丢失,是减数分裂染色体忠实分离所必需的。黏连蛋白在减数分裂I期间从染色体臂上被移除,但在着丝粒周围保留至减数分裂II。我们在此表明,Sgo1是一种在减数分裂I期间保护着丝粒黏连蛋白不被移除所必需的蛋白质,它定位于着丝粒及其周围50 kb区域的黏连蛋白相关区域(CARs)。这个Sgo1结合结构域的建立需要120个碱基对(bp)的核心着丝粒、动粒组分Bub1以及减数分裂特异性因子Spo13。有趣的是,黏连蛋白以及动粒蛋白Iml3和Chl4是Sgo1与着丝粒周围区域结合所必需的,但对Sgo1与核心着丝粒区域结合的必要性较小。最后,我们表明50 kb的Sgo1结合结构域是减数分裂I期间黏连蛋白不被移除的染色体区域。我们的结果确定了减数分裂I期间黏连蛋白不被移除的染色体部分,并表明动粒组分和黏连蛋白本身是建立这个黏连蛋白保护结构域所必需的。