Centromere-associated topoisomerase activity in bloodstream form Trypanosoma brucei.
Centromere-associated topoisomerase activity in bloodstream form Trypanosoma brucei.
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DOI：
10.1093/nar/gkq839
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发表时间：
2011-02
影响因子：
14.9
通讯作者：
Kelly JM
中科院分区：
文献类型：
--
作者：
Obado SO;Bot C;Echeverry MC;Bayona JC;Alvarez VE;Taylor MC;Kelly JM
拓扑异构酶-II在前中期期间在着丝粒处积累，在那里它解析代表姐妹染色单体之间的最后链接的DNA连锁。以前，使用的方法，包括依托泊苷介导的拓扑异构酶-II切割，我们映射着丝粒结构域锥虫，早期分支的真核生物中的染色体分离知之甚少。在这里，我们发现，在血流形式的布氏锥虫中，RNAi介导的拓扑异构酶-II α的耗竭，而不是拓扑异构酶-II β，导致着丝粒定位活性的消除，并且是致命的。这两种表型都可以通过表达T.克鲁兹因此，控制着丝粒特异性拓扑异构酶-II积累/激活的过程在锥虫体内功能上是保守的，尽管这些物种在着丝粒DNA组织中存在长期的进化分离和差异。拓扑异构酶-II的可变羧基末端区域在调节生物功能中具有重要作用。因此，我们生成了T。表达T. cruzi拓扑异构酶-II在羧基末端截短，并在RNAi介导的内源酶消耗后检查着丝粒处的活性。核定位所需的区域被划定为6个残基。在其他生物中，拓扑异构酶-II的类小泛素化已被证明是必要的调节染色体分离。我们提出的证据表明，T。布氏酶不是着丝粒特异性切割活性所必需的。
Topoisomerase-II accumulates at centromeres during prometaphase, where it resolves the DNA catenations that represent the last link between sister chromatids. Previously, using approaches including etoposide-mediated topoisomerase-II cleavage, we mapped centromeric domains in trypanosomes, early branching eukaryotes in which chromosome segregation is poorly understood. Here, we show that in bloodstream form Trypanosoma brucei, RNAi-mediated depletion of topoisomerase-IIα, but not topoisomerase-IIβ, results in the abolition of centromere-localized activity and is lethal. Both phenotypes can be rescued by expression of the corresponding enzyme from T. cruzi. Therefore, processes which govern centromere-specific topoisomerase-II accumulation/activation have been functionally conserved within trypanosomes, despite the long evolutionary separation of these species and differences in centromeric DNA organization. The variable carboxyl terminal region of topoisomerase-II has a major role in regulating biological function. We therefore generated T. brucei lines expressing T. cruzi topoisomerase-II truncated at the carboxyl terminus and examined activity at centromeres after the RNAi-mediated depletion of the endogenous enzyme. A region necessary for nuclear localization was delineated to six residues. In other organisms, sumoylation of topoisomerase-II has been shown to be necessary for regulated chromosome segregation. Evidence that we present here suggests that sumoylation of the T. brucei enzyme is not required for centromere-specific cleavage activity.
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影响因子：
3.7
作者：
Díaz-Martínez LA;Giménez-Abián JF;Azuma Y;Guacci V;Giménez-Martín G;Lanier LM;Clarke DJ
通讯作者：
Clarke DJ
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作者：
Azuma, Yoshiaki;Arnaoutov, Alexei;Dasso, Mary
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Dasso, Mary
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作者：
Deterding, A;Dungey, FA;Steverding, D
通讯作者：
Steverding, D
影响因子：
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作者：
Fukagawa, T
通讯作者：
Fukagawa, T
影响因子：
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作者：
Alsford, Sam;Horn, David
通讯作者：
Horn, David