SUMO-2/3 regulates topoisomerase II in mitosis.
SUMO-2/3 regulates topoisomerase II in mitosis.
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DOI：
10.1083/jcb.200304088
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发表时间：
2003-11-10
影响因子：
7.8
通讯作者：
Dasso, Mary
中科院分区：
文献类型：
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作者：
Azuma, Yoshiaki;Arnaoutov, Alexei;Dasso, Mary
我们分析了非洲爪哇卵提取物在细胞周期中相扑结合物种的丰度。与有丝分裂染色体相关的主要相扑接合产物来自于拓扑异构酶II的相扑接合。在正常情况下，在有丝分裂过程中，拓扑异构酶II只被相扑-2/3修饰，尽管我们在外源相扑-1蛋白的提取物中观察到拓扑异构酶II与相扑-1的接合。抑制相扑结合酶Ubc9(DnUbc9)的显性-负性突变体(DnUbc9)对有丝分裂的拓扑异构酶II活性没有明显影响，但它确实增加了高盐洗涤后有丝分裂染色体上保留的未修饰的拓扑异构酶II的量。DnUbc9不破坏浓缩有丝分裂染色体的组装，也不阻止提取物通过有丝分裂进行，但在中期-后期转变时确实阻止姐妹染色单体的解离。总之，我们的结果表明，相扑接合对于后生动物系统中的染色体分离是重要的，从有丝分裂染色质中动员拓扑异构酶II可能是这一修饰的关键目标。
We have analyzed the abundance of SUMO-conjugated species during the cell cycle in Xenopus egg extracts. The predominant SUMO conjugation products associated with mitotic chromosomes arose from SUMO conjugation of topoisomerase II. Topoisomerase II was modified exclusively by SUMO-2/3 during mitosis under normal circumstances, although we observed conjugation of topoisomerase II to SUMO-1 in extracts with exogenous SUMO-1 protein. Inhibition of SUMO modification by a dominant-negative mutant of the SUMO-conjugating enzyme Ubc9 (dnUbc9) did not detectably alter topoisomerase II activity, but it did increase the amount of unmodified topoisomerase II retained on mitotic chromosomes after high salt washing. dnUbc9 did not disrupt the assembly of condensed mitotic chromosomes or block progression of extracts through mitosis, but it did block the dissociation of sister chromatids at the metaphase–anaphase transition. Together, our results suggest that SUMO conjugation is important for chromosome segregation in metazoan systems, and that mobilization of topoisomerase II from mitotic chromatin may be a key target of this modification.