Modulation of CRP-dependent transcription at the Escherichia coli acsP2 promoter by nucleoprotein complexes:: anti-activation by the nucleoid proteins FIS and IHF
Modulation of CRP-dependent transcription at the Escherichia coli acsP2 promoter by nucleoprotein complexes:: anti-activation by the nucleoid proteins FIS and IHF
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DOI：
10.1046/j.1365-2958.2003.03824.x
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发表时间：
2004-01-01
影响因子：
3.6
通讯作者：
Wolfe, AJ
中科院分区：
文献类型：
--
作者：
Browning, DF;Beatty, CM;Wolfe, AJ
acs编码乙酰辅酶A合成酶，这是一种高亲和力酶，允许细胞在碳饥饿期间吸收乙酸。CRP通过结合位于主要启动子acsP2上游的串联DNA位点激活acs转录。在这里，我们使用电泳迁移率变动分析和DNA酶I足迹分析，以证明类核蛋白FIS和IHF各自结合ACS调控区内的多个位点，FIS成功地与CRP竞争结合其重叠和相邻位点，IHF独立于FIS或CRP结合。使用体外转录测定，我们证明了FIS和IHF独立地降低CRP依赖性acs转录。使用体内报告基因分析，我们发现FIS的DNA位点的破坏或IHF的DNA位点的缺失增加acs转录。我们认为FIS和IHF各自直接作为CRP的抗激活剂，各自在生长过程中的不同时间独立工作，以设定CRP依赖的acs转录水平。
acs encodes acetyl-coenzyme A synthetase, a high-affinity enzyme that allows cells to scavenge for acetate during carbon starvation. CRP activates acs transcription by binding tandem DNA sites located upstream of the major promoter, acsP2. Here, we used electrophoretic mobility shift assays and DNase I footprint analyses to demonstrate that the nucleoid proteins FIS and IHF each bind multiple sites within the acs regulatory region, that FIS competes successfully with CRP for binding to their overlapping and neighbouring sites and that IHF binds independently of either FIS or CRP. Using in vitro transcription assays, we demonstrated that FIS and IHF independently reduce CRP-dependent acs transcription. Using in vivo reporter assays, we showed that disruption of DNA sites for FIS or deletion of DNA sites for IHF increases acs transcription. We propose that FIS and IHF each function directly as anti-activators of CRP, each working independently at different times during growth to set the levels of CRP-dependent acs transcription.