Genetic evidence for a novel interaction between transcriptional activator SoxS and region 4 of the σ(70) subunit of RNA polymerase at class II SoxS-dependent promoters in Escherichia coli.
Genetic evidence for a novel interaction between transcriptional activator SoxS and region 4 of the σ(70) subunit of RNA polymerase at class II SoxS-dependent promoters in Escherichia coli.
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转录活化剂SOX与RNA聚合酶在Escherichia Coli中II类SOXSS依赖性启动子的σ（70）亚基的区域4之间存在新的相互作用的遗传证据。
DOI：
10.1016/j.jmb.2010.12.037
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发表时间：
2011-04-01
影响因子：
5.6
通讯作者：
Wolf RE Jr
中科院分区：
文献类型：
--
作者：
Zafar MA;Sanchez-Alberola N;Wolf RE Jr
大肠杆菌 SoxS 激活 soxRS 调节子基因的转录，从而为细胞提供针对氧化应激的防御。为了应对这种压力，SoxS 被从头合成。由于SoxS的DNA结合位点高度简并，SoxS通过预募集机制有效地激活转录。在预招募中，新合成的 SoxS 首先与 RNA 聚合酶形成二元复合物。然后，这些复合物扫描染色体寻找 I 类和 II 类 SoxS 依赖性启动子，利用 SoxS 和 σ70 的特定 DNA 识别特性将 SoxS 依赖性启动子与大量不存在于启动子中的序列等价 soxbox 区分开来。之前，我们确定SoxS以两种方式与RNA聚合酶相互作用，即与α亚基的DNA结合决定簇进行蛋白质-蛋白质相互作用，以及与“DNA上”和“DNA外”的σ70区域4（σ70 R4）相互作用。在这里，我们解决了 SoxS 和 σ70 R4 如何在 II 类启动子上共存的问题，其中 SoxS 的结合位点部分或完全重叠启动子的 -35 区域，该区域通常由 σ70 R4 结合。为此，我们创建了一个涵盖所有 σ70 R4 的三丙氨酸扫描库。我们确定，σ70 R4 和启动子 -35 区域中的 DNA 之间的相互作用是 I 类启动子的激活所必需的，其中结合位点位于 -35 六聚体的上游，但 II 类启动子不需要它们。相比之下，I 类 (lac) 和 II 类 (galP1) 环 AMP 受体蛋白依赖性启动子的激活需要特定的三个氨基酸序列。我们从这些数据中得出结论，SoxS 和 σ70 R4 在 II 类 SoxS 依赖性启动子处以一种新的方式相互作用，使得这两种蛋白质在 -35 区域中不相互适应，而是在那里的 SoxS 结合阻碍了 σ70 R4 的结合。
Escherichia coli SoxS activates transcription of the genes of the soxRS regulon, which provide the cell's defense against oxidative stress. In response to this stress, SoxS is synthesized de novo. Because the DNA binding site of SoxS is highly degenerate, SoxS efficiently activates transcription by the mechanism of prerecruitment. In prerecruitment, newly synthesized SoxS first forms binary complexes with RNA polymerase. These complexes then scan the chromosome for class I and class II SoxS-dependent promoters, using the specific DNA-recognition properties of SoxS and σ70 to distinguish SoxS-dependent promoters from the vast excess of sequence-equivalent soxboxes that do not reside in promoters. Previously, we determined that SoxS interacts with RNA polymerase in two ways, by making protein-protein interactions with the DNA-binding determinant of the α subunit and by interacting with σ70 region 4 (σ70 R4) both “on-DNA” and “off-DNA”. Here, we address the question of how SoxS and σ70 R4 co-exist at class II promoters, where the binding site for SoxS either partially or completely overlaps the -35 region of the promoter, which is usually bound by σ70 R4. To do so, we created a tri-alanine scanning library that covers all of σ70 R4. We determined that interactions between σ70 R4 and the DNA in the promoter's −35 region are required for activation of class I promoters, where the binding site lies upstream of the −35 hexamer, but they are not required at class II promoters. In contrast, specific three-amino acid stretches are required for activation of class I (lac) and class II (galP1) cyclic AMP receptor protein-dependent promoters. We conclude from these data that SoxS and σ70 R4 interact with each other in a novel way at class II SoxS-dependent promoters such that the two proteins do not accommodate one another in the −35 region but instead SoxS binding there occludes the binding of σ70 R4.
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DOI：
10.1006/bbrc.2002.6559
发表时间：
2002-03-08
影响因子：
3.1
作者：
Griffith, KL;Shah, IM;Wolf, RE
通讯作者：
Wolf, RE
DOI：
10.1073/pnas.0400923101
发表时间：
2004-03-30
影响因子：
11.1
作者：
Gregory, BD;Nickels, BE;Hochschild, A
通讯作者：
Hochschild, A
影响因子：
5.6
作者：
Baxter, Kimberly;Lee, Jennifer;Hinton, Deborah M.
通讯作者：
Hinton, Deborah M.
影响因子：
14.9
作者：
AMABILECUEVAS, CF;DEMPLE, B
通讯作者：
DEMPLE, B
影响因子：
3.2
作者：
Bhende, PM;Egan, SM
通讯作者：
Egan, SM