Insights into transcriptional regulation and σ competition from an equilibrium model of RNA polymerase binding to DNA
Insights into transcriptional regulation and σ competition from an equilibrium model of RNA polymerase binding to DNA
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DOI：
10.1073/pnas.0600828103
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发表时间：
2006-04-04
影响因子：
11.1
通讯作者：
Gross, CA
中科院分区：
文献类型：
--
作者：
Grigorova, IL;Phleger, NJ;Gross, CA
为了探索允许通过活体内RNA聚合酶的激活剂招募和/或竞争来调节转录的情景，我们使用了一个RNA聚合酶与DNA结合的平衡模型，该模型受本工作中测量的每个细胞的总RNA聚合酶(E)和西格玛(70)的值限制。我们的每个细胞的E和Sigma(70)的数量与大多数文献中的主要数据一致，表明在体内(I)只有一小部分RNA聚合酶(<；20%)参与延伸，(Ii)Sigma(70)超过总E。模拟RNA聚合酶在启动子、非特异性DNA结合部位和细胞质之间的分配表明，即使是弱启动子在体内也会被E Sigma(70)饱和，除非E Sigma(70)与非特异性DNA结合相当显著。此外，该模型还预测，只有当启动子总数超过聚合酶总量(不包括延伸所涉及的聚合酶)时，Sigma S才会竞争与E的结合，并且弱启动子将优先受到Sigma竞争的影响。
To explore scenarios that permit transcription regulation by activator recruitment of RNA polymerase and or competition in vivo, we used an equilibrium model of RNA polymerase binding to DNA constrained by the values of total RNA polymerase (E) and sigma(70) per cell measured in this work. Our numbers of E and sigma(70) per cell, which are consistent with most of the primary data in the literature, suggest that in vivo (i) only a minor fraction of RNA polymerase (< 20%) is involved in elongation and (ii) sigma(70) is in excess of total E. Modeling the partitioning of RNA polymerase between promoters, nonspecific DNA binding sites, and the cytoplasm suggested that even weak promoters will be saturated with E sigma(70) in vivo unless nonspecific DNA binding by E sigma(70) is rather significant. In addition, the model predicted that sigma s compete for binding to E only when their total number exceeds the total amount of RNA polymerase (excluding that involved in elongation) and that weak promoters will be preferentially subjected to sigma competition.