Direct interaction between Escherichia coli RNA polymerase and the zinc ribbon domains of DNA topoisomerase I
Direct interaction between Escherichia coli RNA polymerase and the zinc ribbon domains of DNA topoisomerase I
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DOI：
10.1074/jbc.m303403200
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发表时间：
2003-08-15
影响因子：
4.8
通讯作者：
Tse-Dinh, YC
中科院分区：
文献类型：
--
作者：
Cheng, BK;Zhu, CX;Tse-Dinh, YC
大肠杆菌DNA拓扑异构酶I（由topA基因编码）对于维持稳态DNA超螺旋是重要的，并且已被证明影响重要的细胞过程，包括转录。还需要拓扑异构酶I活性来去除在转录延伸期间由进行性RNA聚合酶复合物在DNA模板上产生的超负超螺旋。在拓扑异构酶I不存在的情况下，超负超螺旋的积累可导致新生转录物和模板链形成R环，从而抑制转录延伸。我们用亲和层析和重叠印迹法证明了E.大肠杆菌DNA拓扑异构酶I直接与RNA聚合酶复合物相互作用。蛋白质间的相互作用涉及RNA聚合酶的β '亚基和E. coliDNA拓扑异构酶I与许多转录因子中的锌带结构域同源。这种直接相互作用可以将拓扑异构酶I的松弛活性带到需要其活性的转录位点。其他IA型拓扑异构酶（包括哺乳动物拓扑异构酶III）的锌带C-末端结构域也可能有助于将酶活性与其生理功能联系起来，可能包括复制、转录、重组和修复。
Escherichia coli DNA topoisomerase I (encoded by the topA gene) is important for maintaining steady-state DNA supercoiling and has been shown to influence vital cellular processes including transcription. Topoisomerase I activity is also needed to remove hypernegative supercoiling generated on the DNA template by the progressing RNA polymerase complex during transcription elongation. The accumulation of hypernegative supercoiling in the absence of topoisomerase I can lead to R-loop formation by the nascent transcript and template strand, leading to suppression of transcription elongation. Here we show by affinity chromatography and overlay blotting that E. coli DNA topoisomerase I interacts directly with the RNA polymerase complex. The protein-protein interaction involves the beta' subunit of RNA polymerase and the C-terminal domains of E. coli DNA topoisomerase I, which are homologous to the zinc ribbon domains in a number of transcription factors. This direct interaction can bring the topoisomerase I relaxing activity to the site of transcription where its activity is needed. The zinc ribbon C-terminal domains of other type IA topoisomerases, including mammalian topoisomerase III, may also help link the enzyme activities to their physiological functions, potentially including replication, transcription, recombination, and repair.