Lacour Stephan, Kolb Annie, Boris Zehnder Alexander Jakob, Landini Paolo
Swiss Federal Institute of Environmental Technology (EAWAG), Uberlandstrasse 133, CH-8600 Dübendorf, Switzerland.
Biochem Biophys Res Commun. 2002 Apr 12;292(4):922-30. doi: 10.1006/bbrc.2002.6744.
Transcription of the Escherichia coli aidB gene is controlled by an Esigma(S)-dependent promoter (PaidB) and is poorly transcribed by the Esigma(70) form of RNA polymerase in the absence of additional factors. In this report, we investigate the interaction between PaidB and either the Esigma(70) or the Esigma(S) forms of RNA polymerase in vitro. We show that although Esigma(70) can bind the aidB promoter, its interaction with the promoter results in the formation of an open complex inefficient in transcription initiation and sensitive to heparin challenge. Deletion of the C residue at position -13 of PaidB (Delta-13C) slightly impaired transcription initiation by Esigma(S), consistent with the role of -13C as a specific feature of Esigma(S)-dependent promoters. However, Esigma(S) could still bind and initiate transcription from the Delta-13C mutant aidB promoter more efficiently than Esigma(70), suggesting that sequence elements other than the -13C play an important role in specific promoter recognition by Esigma(S).
大肠杆菌aidB基因的转录受一个依赖于Esigma(S)的启动子（PaidB）控制，在没有其他因子的情况下，RNA聚合酶的Esigma(70)形式对其转录效率很低。在本报告中，我们在体外研究了PaidB与RNA聚合酶的Esigma(70)或Esigma(S)形式之间的相互作用。我们发现，虽然Esigma(70)能够结合aidB启动子，但其与启动子的相互作用导致形成一种在转录起始方面效率低下且对肝素攻击敏感的开放复合物。在PaidB的 -13位缺失C残基（Delta-13C）会轻微损害Esigma(S)介导的转录起始，这与 -13C作为依赖于Esigma(S)的启动子的一个特定特征的作用相一致。然而，Esigma(S)仍然能够结合Delta-13C突变体aidB启动子并比Esigma(70)更有效地启动转录，这表明除了 -13C之外的序列元件在Esigma(S)对特定启动子的识别中起重要作用。
