Tatti K M, Jones C H, Moran C P
Department of Microbiology & Immunology, Emory University, School of Medicine, Atlanta, Georgia 30322.
J Bacteriol. 1991 Dec;173(24):7828-33. doi: 10.1128/jb.173.24.7828-7833.1991.
During sporulation in Bacillus subtilis, new RNA polymerase sigma factors are produced. These sigma factors direct the transcription of genes that are required for this cellular differentiation. In order to determine the role of each sigma factor in this process, it is necessary to know which promoters are recognized by each sigma factor. The spoIIID gene product plays an important role in the establishment of mother cell-specific gene expression during sporulation. We found that substitution of an alanine at position 124 of the sporulation-specific sigma factor sigma E suppressed the effect of a single-base-pair transition at position -13 of the spoIIID promoter. This alanine substitution in sigma E did not suppress the effect of a transversion at position -12 of the spoIIID promoter. The allele specificity of the interaction between sigma E and the spoIIID promoter is strong evidence that sigma E directs transcription from the spoIIID promoter during sporulation. Position 124 in sigma E is located within a region that is highly conserved among the regions in other sigma factors that probably interact with the -10 regions of their cognate promoters.
在枯草芽孢杆菌的芽孢形成过程中，会产生新的RNA聚合酶σ因子。这些σ因子指导该细胞分化所需基因的转录。为了确定每个σ因子在此过程中的作用，有必要了解每个σ因子识别哪些启动子。芽孢形成特异性σ因子σE第124位的丙氨酸替代抑制了spoIIID启动子第-13位单碱基对转换的效应。σE中的这种丙氨酸替代并未抑制spoIIID启动子第-12位颠换的效应。σE与spoIIID启动子之间相互作用的等位基因特异性有力地证明了在芽孢形成过程中σE指导来自spoIIID启动子的转录。σE中的第124位位于其他σ因子中可能与其同源启动子的-10区相互作用的区域中高度保守的区域内。
