Oguiza J A, Marcos A T, Malumbres M, Martín J F
Area of Microbiology, Faculty of Biology, University of León, Spain.
J Bacteriol. 1996 Jan;178(2):550-3. doi: 10.1128/jb.178.2.550-553.1996.
Four rpoD hybridizing signals have been identified in the chromosome of Brevibacterium lactofermentum. Two rpoD-like genes, sigA and sigB, have been cloned and sequenced, and they encode principal sigma factors of the RNA polymerase. The deduced amino acid sequences of SigA and SigB showed very high similarities to those of Mycobacterium smegmatis MysA and MysB proteins, respectively, and also to those of HrdB proteins from different Streptomyces species. SigA and SigB maintain the conserved motifs of sigma 70-like principal sigma factors. sigB is closely linked to the dtxR gene (encoding a repressor of iron-regulated promoters homologous to the diphtheria toxin repressor from Corynebacterium diphtheriae.
在乳酸发酵短杆菌的染色体中已鉴定出四个rpoD杂交信号。已克隆并测序了两个类rpoD基因sigA和sigB，它们编码RNA聚合酶的主要σ因子。SigA和SigB推导的氨基酸序列分别与耻垢分枝杆菌MysA和MysB蛋白的序列以及不同链霉菌属的HrdB蛋白的序列具有非常高的相似性。SigA和SigB保留了σ70样主要σ因子的保守基序。sigB与dtxR基因紧密相连（dtxR基因编码一种铁调节启动子的阻遏物，与来自白喉棒状杆菌的白喉毒素阻遏物同源）。
