Kolb A, Kotlarz D, Kusano S, Ishihama A
Unité de Physicochimie des Macromolécules Biologiques, URA 1149 du CNRS, Paris, France.
Nucleic Acids Res. 1995 Mar 11;23(5):819-26. doi: 10.1093/nar/23.5.819.
A series of gal promoter mutants has been used to compare the in vitro selectivities of the two forms of Escherichia coli RNA polymerase, E sigma 38 and E sigma 70. In the absence of the CRP-cAMP complex, E sigma 38 shows a strong preference for the ga/P1 promoter, whereas E sigma 70 preferentially initiates transcription from the ga/P2 promoter. E sigma 38 selectivity is not affected by the nature and position of the upstream sequences or by the phasing between synthetic upstream curved sequences and the -10 regions. In fact, all effects of mutations in the extended -10 region can be accounted for without evoking strong new sequence preferences for E sigma 38. Finally, both E sigma 38 and E sigma 70 initiate transcription from the ga/P1 promoter in the presence of CRP-cAMP complex and support direct cAMP-CRP activation at several CRP-dependent promoters.
一系列gal启动子突变体已被用于比较两种形式的大肠杆菌RNA聚合酶E sigma 38和E sigma 70的体外选择性。在没有CRP-cAMP复合物的情况下，E sigma 38对ga/P1启动子表现出强烈偏好，而E sigma 70优先从ga/P2启动子起始转录。E sigma 38的选择性不受上游序列的性质和位置或合成上游弯曲序列与-10区域之间相位的影响。事实上，在不引发E sigma 38强烈新序列偏好的情况下，可以解释延伸-10区域突变的所有影响。最后，在存在CRP-cAMP复合物的情况下，E sigma 38和E sigma 70都从ga/P1启动子起始转录，并在几个CRP依赖性启动子处支持直接的cAMP-CRP激活。
