Transcription from bacteriophage lambda pR promoter is regulated independently and antagonistically by DksA and ppGpp.
Transcription from bacteriophage lambda pR promoter is regulated independently and antagonistically by DksA and ppGpp.
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DOI：
10.1093/nar/gkp676
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发表时间：
2009-11
影响因子：
14.9
通讯作者：
Szalewska-Palasz A
中科院分区：
文献类型：
--
作者：
Łyzen R;Kochanowska M;Wegrzyn G;Szalewska-Palasz A
严紧反应效应物鸟苷四磷酸（ppGpp）通过影响各种启动子的活性来调节细菌中的基因表达和生理过程。RNA聚合酶相互作用蛋白DksA被认为是ppGpp效应的辅因子；然而，有报道表明这些调节因子具有独立的作用。噬菌体λ的主要裂解启动子pR受到严紧反应和ppGpp的下调。在此，我们提供证据表明DksA在体外重组系统中显著刺激pR起始的转录。DksA在体内对pR的活性也是必不可少的。在体外两种调节因子都存在的情况下，DksA介导的pR起始转录的激活作用优于ppGpp的效应。讨论了ppGpp和DksA的相反调节在λ噬菌体发育中的可能作用。DksA介导的pR转录激活的主要机制涉及促进RNA聚合酶与启动子区域的结合，从而导致更高效的转录起始。因此，我们的结果为第一个被ppGpp抑制且可在体内和体外被DksA蛋白刺激的启动子提供了证据。所以，DksA在转录调节中的作用可能不仅是独立的，而且与ppGpp是拮抗的。
The stringent response effector, guanosine tetraphosphate (ppGpp), adjust gene expression and physiology in bacteria, by affecting the activity of various promoters. RNA polymerase-interacting protein, DksA, was proposed to be the co-factor of ppGpp effects; however, there are reports suggesting independent roles of these regulators. Bacteriophage λ major lytic promoter, pR, is down-regulated by the stringent response and ppGpp. Here, we present evidence that DksA significantly stimulates pR-initiated transcription in vitro in the reconstituted system. DksA is also indispensable for pR activity in vivo. DksA-mediated activation of pR-initiated transcription is predominant over ppGpp effects in the presence of both regulators in vitro. The possible role of the opposite regulation by ppGpp and DksA in λ phage development is discussed. The major mechanism of DksA-mediated activation of transcription from pR involves facilitating of RNA polymerase binding to the promoter region, which results in more productive transcription initiation. Thus, our results provide evidence for the first promoter inhibited by ppGpp that can be stimulated by the DksA protein both in vivo and in vitro. Therefore, DksA role could be not only independent but antagonistic to ppGpp in transcription regulation.
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影响因子：
64.5
作者：
Artsimovitch, I;Patlan, V;Vassylyev, DG
通讯作者：
Vassylyev, DG
影响因子：
3.6
作者：
Aberg, Anna;Shingler, Victoria;Balsalobre, Carlos
通讯作者：
Balsalobre, Carlos
影响因子：
3.6
作者：
Perron, K;Comte, R;van Delden, C
通讯作者：
van Delden, C
影响因子：
4.8
作者：
Potrykus, K;Wegrzyn, G;Hernandez, VJ
通讯作者：
Hernandez, VJ
DOI：
10.1073/pnas.0501170102
发表时间：
2005-05-31
影响因子：
11.1
作者：
Paul, BJ;Berkmen, MB;Gourse, RL
通讯作者：
Gourse, RL