Transcriptional occlusion caused by overlapping promoters.
Transcriptional occlusion caused by overlapping promoters.
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由重叠启动子引起的转录封闭。
DOI：
10.1073/pnas.1323413111
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发表时间：
2014
影响因子：
11.1
通讯作者：
Silhavy,ThomasJ
中科院分区：
文献类型：
--
作者：
Zafar,MAmmar;Carabetta,ValerieJ;Mandel,MarkJ;Silhavy,ThomasJ
RPOS(σ38)是细胞在应激条件下生存所必需的，但如果产生不当，它可以抑制生长，因此，它的生产和活性受到精心调控。CRL是一种不结合DNA的转录激活剂，通过刺激rpos与核心聚合酶之间的相互作用来增强rpos的活性。该基因有两个重叠的启动子，一个是看家的，依赖于RpoD(σ70)的启动子，另一个是RpoN(σ54)启动子，在氮素限制下强烈上调。然而，来自RpoN启动子的转录阻止了来自RpoD启动子的转录，并且RpoN依赖的转录本缺乏核糖体结合位点。因此，RpoN启动子的激活产生了一个长的非编码RNA，它仅仅通过制造就可以沉默CR1基因的表达。这种优雅而经济的机制允许CRL合成的近乎瞬时减少，而不需要处理调节因子，抑制RPO的活性，以便在氮素限制条件下更快地生长。
RpoS (σ38) is required for cell survival under stress conditions, but it can inhibit growth if produced inappropriately and, consequently, its production and activity are elaborately regulated. Crl, a transcriptional activator that does not bind DNA, enhances RpoS activity by stimulating the interaction between RpoS and the core polymerase. Thecrlgene has two overlapping promoters, a housekeeping, RpoD- (σ70) dependent promoter, and an RpoN (σ54) promoter that is strongly up-regulated under nitrogen limitation. However, transcription from the RpoN promoter prevents transcription from the RpoD promoter, and the RpoN-dependent transcript lacks a ribosome-binding site. Thus, activation of the RpoN promoter produces a long noncoding RNA that silencescrlgene expression simply by being made. This elegant and economical mechanism, which allows a near-instantaneous reduction in Crl synthesis without the need for transacting regulatory factors, restrains the activity of RpoS to allow faster growth under nitrogen-limiting conditions.