Dynek Jasmin N, Smith Susan
Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
Science. 2004 Apr 2;304(5667):97-100. doi: 10.1126/science.1094754.
Cohesins keep sister chromatids associated from the time of their replication in S phase until the onset of anaphase. In vertebrate cells, two distinct pathways dissociate cohesins, one acts on chromosome arms and the other on centromeres. Here, we describe a third pathway that acts on telomeres. Knockdown of tankyrase 1, a telomeric poly(ADP-ribose) polymerase caused mitotic arrest. Chromosomes aligned normally on the metaphase plate but were unable to segregate. Sister chromatids separated at centromeres and arms but remained associated at telomeres, apparently through proteinaceous bridges. Thus, telomeres may require a unique tankyrase 1-dependent mechanism for sister chromatid resolution before anaphase.
黏连蛋白使姐妹染色单体从S期复制时起就保持相连，直至后期开始。在脊椎动物细胞中，有两条不同的途径可使黏连蛋白解离，一条作用于染色体臂，另一条作用于着丝粒。在此，我们描述了第三条作用于端粒的途径。端粒聚（ADP - 核糖）聚合酶端粒酶1的敲低导致有丝分裂停滞。染色体在中期板上正常排列，但无法分离。姐妹染色单体在着丝粒和染色体臂处分离，但在端粒处仍通过蛋白质桥相连。因此，在后期之前，端粒可能需要一种独特的依赖端粒酶1的机制来实现姐妹染色单体的分离。
