Steffen P, Goyard S, Ullmann A
Unité de Biochimie des Régulations Cellulaires, Institut Pasteur, Paris, France.
Mol Microbiol. 1997 Mar;23(5):945-54. doi: 10.1046/j.1365-2958.1997.2741639.x.
We have cloned the rpoD gene coding for the major sigma factor of Bordetella pertussis. The deduced amino acid sequence reveals a protein of 733 residues which has extensive amino acid homology with the principal sigma factors of a number of divergent prokaryotes. It is larger than most sigma factors identified to date, having a molecular mass of 81.3 kDa. We have designated this factor sigma 80. In a heterologous complementation assay, B. pertussis rpoD was able to complement the Escherichia coli rpoD temperature-sensitive mutant UQ285. Furthermore, B. pertussis rpoD conferred better specificity to the E. coli RNA polymerase, allowing increased expression of the B. pertussis virulence-associated tha promoter, but could not activate the ptx and cya promoters in the E. coli UQ285 strains carrying the B. pertussis bvg locus. We discuss the implications of these results on the mechanisms involved in the activation of virulence-associated promoters.
我们已经克隆了编码百日咳博德特氏菌主要σ因子的rpoD基因。推导的氨基酸序列显示该蛋白由733个残基组成，与许多不同原核生物的主要σ因子具有广泛的氨基酸同源性。它比迄今为止鉴定的大多数σ因子都要大，分子量为81.3 kDa。我们将这个因子命名为σ80。在异源互补试验中，百日咳博德特氏菌rpoD能够互补大肠杆菌rpoD温度敏感突变体UQ285。此外，百日咳博德特氏菌rpoD赋予大肠杆菌RNA聚合酶更好的特异性，使百日咳博德特氏菌毒力相关tha启动子的表达增加，但不能激活携带百日咳博德特氏菌bvg位点的大肠杆菌UQ285菌株中的ptx和cya启动子。我们讨论了这些结果对毒力相关启动子激活机制的影响。
