A two-step scaffolding model for mitotic chromosome assembly
A two-step scaffolding model for mitotic chromosome assembly
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DOI：
10.1016/s1534-5807(03)00092-3
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发表时间：
2003-04-01
影响因子：
11.8
通讯作者：
Laemmli, UK
中科院分区：
文献类型：
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作者：
Maeshima, K;Laemmli, UK
拓扑异构酶Ⅱ α（topoIIalpha）和13S凝聚素都是有丝分裂染色体装配所必需的。在这里，我们表明，他们构成的两个主要组成部分的染色体支架组蛋白耗尽的染色体。研究表明，对于苛刻的提取程序，支架的结构稳定性和染色体形状是由ATP或其不可水解的类似物介导的，但不是ADP。TopoIIalpha和13S凝聚素组分免疫定位于天然样染色体中的径向限制性纵向支架。topoIIalpha和凝聚素的双重染色产生了一个理发师极外观的脚手架，其中topoIIalpha和凝聚素富集的“珠”交替，这种结构似乎是由两个并列，或卷曲，链产生。细胞周期研究表明，13S凝聚素似乎不参与前期染色单体的组装，它们缺乏这种复合物，但含有拓扑II α定义的（介导的？）脚手架凝聚素仅在原中期转变期间结合。这两个步骤的组装过程中，提出了产生理发师极外观的原生一样的脚手架。
Topoisomerase IIalpha (topoIIalpha) and 13S condensin are both required for mitotic chromosome assembly. Here we show that they constitute the two main components of the chromosomal scaffold on histone-depleted chromosomes. The structural stability and chromosomal shape of the scaffolding toward harsh extraction procedures are shown to be mediated by ATP or its nonhydrolyzable analogs, but not ADP. TopoIIalpha and 13S condensin components immunolocalize to a radially restricted, longitudinal scaffolding in native-like chromosomes. Double staining for topoIIalpha and condensin generates a barber pole appearance of the scaffolding, where topoIIalpha - and condensin-enriched "beads" alternate; this structure appears to be generated by two juxtaposed, or coiled, chains. Cell cycle studies establish that 13S condensin appears not to be involved in the assembly of prophase chromatids; they lack this complex but contain a topoIIalpha-defined (-mediated?) scaffolding. Condensin associates only during the proto metaphase transition. This two-step assembly process is proposed to generate the barber pole appearance of the native-like scaffolding.