Contribution of hCAP-D2, a non-SMC subunit of condensin I, to chromosome and chromosomal protein dynamics during mitosis
Contribution of hCAP-D2, a non-SMC subunit of condensin I, to chromosome and chromosomal protein dynamics during mitosis
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DOI：
10.1128/mcb.25.2.740-750.2005
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发表时间：
2005-01-01
影响因子：
5.3
通讯作者：
Legagneux, V
中科院分区：
文献类型：
--
作者：
Watrin, E;Legagneux, V
凝缩蛋白是异五聚体复合物，最初被鉴定为有丝分裂染色体的结构成分。它们由两个 SMC（染色体结构维持）和三个非 SMC 亚基组成。凝缩蛋白在有丝分裂过程中姐妹染色单体的解析和分离以及有丝分裂染色体组装的某些方面发挥作用。存在两种不同的凝缩蛋白复合物：凝缩蛋白 I 和凝缩蛋白 II，它们的不同之处仅在于它们的非 SMC 亚基。在这里，我们使用 RNA 干扰方法来消耗 HeLa 细胞中的 hCAP-D2（凝缩蛋白 I 的非 SMC 亚基）。我们发现 hCAP-H（凝缩蛋白 I 的另一个非 SMC 亚基）与有丝分裂染色体的关联取决于 hCA-P-D2 的存在。此外，在没有 hCAP-D2 的情况下，由拓扑异构酶 II 和 hCAP-E 定位定义的染色单体轴会被破坏，姐妹染色单体的分辨率和分离也会受到损害。此外，hCAP-D2 缺失会影响中期的染色体排列并延迟进入后期。这表明凝缩蛋白 I 参与染色体动粒和有丝分裂纺锤体微管之间的正确附着。这些结果是相对于消耗两种凝缩蛋白复合物的影响进行讨论的。
Condensins are heteropentameric complexes that were first identified as structural components of mitotic chromosomes. They are composed of two SMC (structural maintenance of chromosomes) and three non-SMC subunits. Condensins play a role in the resolution and segregation of sister chromatids during mitosis, as well as in some aspects of mitotic chromosome assembly. Two distinct condensin complexes, condensin I and condensin II, which differ only in their non-SMC subunits, exist. Here, we used an RNA interference approach to deplete hCAP-D2, a non-SMC subunit of condensin I, in HeLa cells. We found that the association of hCAP-H, another non-SMC subunit of condensin I, with mitotic chromosomes depends on the presence of hCA-P-D2. Moreover, chromatid axes, as defined by topoisomerase II and hCAP-E localization, are disorganized in the absence of hCAP-D2, and the resolution and segregation of sister chromatids are impaired. In addition, hCAP-D2 depletion affects chromosome alignment in metaphase and delays entry into anaphase. This suggests that condensin I is involved in the correct attachment between chromosome kinetochores and microtubules of the mitotic spindle. These results are discussed relative to the effects of depleting both condensin complexes.