Small things considered: the small accessory subunits of RNA polymerase in Gram-positive bacteria.
Small things considered: the small accessory subunits of RNA polymerase in Gram-positive bacteria.
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DOI：
10.1093/femsre/fuv005
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发表时间：
2015-07
影响因子：
11.3
通讯作者：
A. Weiss;L. Shaw
中科院分区：
文献类型：
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作者：
A. Weiss;L. Shaw
革兰氏阳性菌中依赖DNA的RNA聚合酶核心酶由七个亚基组成。虽然其中四个亚基（α2ββ（'））是必需的，但三个较小的亚基δ、ε和ω（ε 9-21.5 kDa）被认为是辅助亚基。几十年来，δ和ω都被视为RNAP的组成部分;然而，ε直到最近才被描述。在功能上，这三个小亚基执行各种任务，对革兰氏阳性细菌的转录过程产生重要的支持作用。虽然ω被认为具有广泛的作用，从维持RNAP的结构完整性到σ因子募集，但到目前为止，ε的唯一建议功能是保护细胞免受噬菌体感染。第三个亚基δ已被证明在维持转录特异性方面具有明显的影响，因此在细胞适应性中具有关键作用。总的来说，所有三个辅助亚基，虽然在实验室条件下是不稳定的，但通常被认为是正确的RNAP功能的关键。在此，我们提供了一个概述的可用文献中的每个亚基，总结了里程碑式的发现，加深了我们对这些蛋白质及其功能的理解，并概述了未来的挑战，在理解这些小亚基的转录过程中的作用。
The DNA-dependent RNA polymerase core enzyme in Gram-positive bacteria consists of seven subunits. Whilst four of them (α2ββ(')) are essential, three smaller subunits, δ, ε and ω (∼9-21.5 kDa), are considered accessory. Both δ and ω have been viewed as integral components of RNAP for several decades; however, ε has only recently been described. Functionally these three small subunits carry out a variety of tasks, imparting important, supportive effects on the transcriptional process of Gram-positive bacteria. While ω is thought to have a wide range of roles, reaching from maintaining structural integrity of RNAP to σ factor recruitment, the only suggested function for ε thus far is in protecting cells from phage infection. The third subunit, δ, has been shown to have distinct influences in maintaining transcriptional specificity, and thus has a key role in cellular fitness. Collectively, all three accessory subunits, although dispensable under laboratory conditions, are often thought to be crucial for proper RNAP function. Herein we provide an overview of the available literature on each subunit, summarizing landmark findings that have deepened our understanding of these proteins and their function, and outline future challenges in understanding the role of these small subunits in the transcriptional process.