Rieder C L, Cole R
Wadsworth Center, New York State Dept of Health, PO Box 509, Albany, New York 12201-0509, USA.
J Cell Sci. 1999 Aug;112 ( Pt 16):2607-13. doi: 10.1242/jcs.112.16.2607.
The equal distribution of chromosomes during mitosis and meiosis is dependent on the maintenance of sister chromatid cohesion. In this commentary we review the evidence that, during meiosis, the mechanism underlying the cohesion of chromatids along their arms is different from that responsible for cohesion in the centromere region. We then argue that the chromatids on a mitotic chromosome are also tethered along their arms and in the centromere by different mechanisms, and that the functional action of these two mechanisms can be temporally separated under various conditions. Finally, we demonstrate that in the absence of a centromeric tether, arm cohesion is sufficient to maintain chromatid cohesion during prometaphase of mitosis. This finding provides a straightforward explanation for why mutants in proteins responsible for centromeric cohesion in Drosophila (e.g. ord, mei-s332) disrupt meiosis but not mitosis.
有丝分裂和减数分裂过程中染色体的均等分配依赖于姐妹染色单体黏连的维持。在这篇评论中，我们回顾了相关证据，即在减数分裂过程中，染色单体沿其臂部黏连的机制不同于负责着丝粒区域黏连的机制。然后我们认为，有丝分裂染色体上的染色单体同样通过不同机制沿其臂部和着丝粒相连，并且在各种条件下这两种机制的功能作用在时间上可以分离。最后，我们证明在没有着丝粒连接的情况下，臂部黏连足以在有丝分裂的前中期维持染色单体的黏连。这一发现为为什么果蝇中负责着丝粒黏连的蛋白质突变体（如ord、mei-s332）会破坏减数分裂但不影响有丝分裂提供了一个直接的解释。
