Gussin G N, Temple E, Brown S E, Court D
Gene. 1986;46(2-3):171-80. doi: 10.1016/0378-1119(86)90401-4.
A 2-bp insertion between the -10 and -35 regions of the pRE promoter of bacteriophage lambda reverses the effect of the activator protein, CII, on transcription from pRE in vitro. The mutant promoter is weakly constitutive in the absence of cII protein and repressed in its presence. This is in sharp contrast to wild-type pRE which is inactive in the absence of cII protein and stimulated at least 1000-fold in its presence (Shih and Gussin, 1984a; McClure and Hoopes, 1985). These effects are explained by the creation of a new -35 region with weak homology to the -35 consensus sequence for Escherichia coli promoters, and by the altered spatial relationship between the -35 region and the CII-binding site. This interpretation was confirmed by analysis of double mutants containing known cy (pRE) mutations together with the 2-bp insertion. Insertion of 4 bp or deletion of 2 bp completely inactivates pRE in the presence or absence of cII protein, again indicating that activation is dependent upon proper spacing between the -35 region and the transcription start point.
噬菌体λ的pRE启动子的-10和-35区域之间插入2个碱基对会逆转激活蛋白CII对体外pRE转录的影响。该突变启动子在无cII蛋白时弱组成型表达，在有cII蛋白时被抑制。这与野生型pRE形成鲜明对比，野生型pRE在无cII蛋白时无活性，在有cII蛋白时被刺激至少1000倍（Shih和Gussin，1984a；McClure和Hoopes，1985）。这些效应可通过产生一个与大肠杆菌启动子的-35共有序列具有弱同源性的新-35区域，以及-35区域与CII结合位点之间改变的空间关系来解释。通过分析含有已知cy（pRE）突变以及2个碱基对插入的双突变体，证实了这一解释。插入4个碱基对或缺失2个碱基对会在有或无cII蛋白时使pRE完全失活，这再次表明激活依赖于-35区域与转录起始点之间的适当间距。
