Termination factor Rho and its cofactors NusA and NusG silence foreign DNA in E-coli
Termination factor Rho and its cofactors NusA and NusG silence foreign DNA in E-coli
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DOI：
10.1126/science.1152763
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发表时间：
2008-05-16
期刊：
影响因子：
56.9
通讯作者：
Nudler, Evgeny
中科院分区：
文献类型：
--
作者：
Cardinale, Christopher J.;Washburn, Robert S.;Nudler, Evgeny
RNA聚合酶对细菌基因组的转录必须在特定的点终止。转录可以被Rho因子终止，Rho因子是肠道细菌中的一种重要蛋白质。我们使用了抑制Rho的抗生素双环素，在全基因组范围内评估了它的作用。Rho被发现是基因表达的全球调节因子，将大肠杆菌的转录与翻译需求相匹配。我们还发现，在大肠杆菌中，被Rho抑制最多的基因是原噬菌体和基因组的其他水平获得部分。消除这些外来DNA元件会增加对双环素的耐药性。尽管Rho仍然是必不可少的，但这种基因组减少的细菌不再需要Rho辅助因子NusA和NusG。野生型大肠杆菌中隐蔽的RAC噬菌体的缺失增加了对双环素的抗性，并允许缺失nusG。因此，需要在NusA和NusG的支持下终止Rho，以抑制外源基因的毒性活性。
Transcription of the bacterial genome by the RNA polymerase must terminate at specific points. Transcription can be terminated by Rho factor, an essential protein in enterobacteria. We used the antibiotic bicyclomycin, which inhibits Rho, to assess its role on a genome-wide scale. Rho is revealed as a global regulator of gene expression that matches Escherichia coli transcription to translational needs. We also found that genes in E. coli that are most repressed by Rho are prophages and other horizontally acquired portions of the genome. Elimination of these foreign DNA elements increases resistance to bicyclomycin. Although rho remains essential, such reduced-genome bacteria no longer require Rho cofactors NusA and NusG. Deletion of the cryptic rac prophage in wild-type E. coli increases bicyclomycin resistance and permits deletion of nusG. Thus, Rho termination, supported by NusA and NusG, is required to suppress the toxic activity of foreign genes.