PspF and IHF bind co-operatively in the psp promoter-regulatory region of Escherichia coli
PspF and IHF bind co-operatively in the psp promoter-regulatory region of Escherichia coli
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DOI：
10.1046/j.1365-2958.1997.4791844.x
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发表时间：
1997-08-01
影响因子：
3.6
通讯作者：
Model, P
中科院分区：
文献类型：
--
作者：
Jovanovic, G;Model, P
与 psp 增强子结合的 PspF 激活大肠杆菌噬菌体休克蛋白 (psp) 操纵子的 E sigma(54) 全酶依赖性转录，并自动抑制其自身的 sigma(70) 依赖性转录，从而将其浓度保持在较低水平。先前已经证明，整合宿主因子（IHF）与位于 psp 核心启动子和 PspF 结合位点之间的 DNA 位点结合可刺激 psp 表达。我们在此表明野生型 IHF 强烈延迟含有 psp 启动子区域的 DNA。在体外，PspF 与 psp 增强子的结合促进了 IHF 的结合，而 IHF 与 pspF-pspA-E 启动子调控区的结合则增加了 PspF 与上游激活序列 (UAS) 结合的功效。这是激活剂和 IHF 在 sigma(54) 依赖性系统中协同结合的首次演示。在不存在 IHF 的情况下，pspF 转录的体内自动调节被解除，因此 PspF 产量增加，表明 IHF 在体内增强 PspF 与 psp 增强子的结合。
PspF bound to the psp enhancer activates E sigma(54) holoenzyme-dependent transcription of the Escherichia coli phage-shock protein (psp) operon and autogenously represses its own sigma(70)-dependent transcription, thereby keeping its concentration at a low level. It has been demonstrated previously that integration host factor (IHF) bound to a DNA site located between the psp core promoter and the PspF binding sites stimulates psp expression. We show here that wild-type IHF strongly retards DNA containing the psp promoter region. In vitro, PspF binding to the psp enhancer facilitates IHF binding, while IHF binding to the pspF-pspA-E promoter-regulatory region increases the efficacy of PspF binding to the upstream activating sequences (UASs). This is the first demonstration of co-operative binding of an activator and IHF in a sigma(54)-dependent system. In the absence of IHF, in vivo autoregulation of pspF transcription is lifted and, consequently, PspF production is increased, indicating that IHF enhances PspF binding to the psp enhancer in vivo.