Mytelka D S, Chamberlin M J
Graduate Group in Genetics, University of California, Berkeley 94720, USA.
J Bacteriol. 1996 Jan;178(1):24-34. doi: 10.1128/jb.178.1.24-34.1996.
We have cloned the Escherichia coli fliAZY operon, which contains the fliA gene (the alternative sigma factor sigma F) and two novel genes, fliZ and fliY. Transcriptional mapping of this operon shows two start sites, one of which is preceded by a canonical E sigma F-dependent consensus and is dependent on sigma F for expression in vivo and in vitro. We have overexpressed and purified sigma F and demonstrated that it can direct core polymerase to E sigma F-dependent promoters. FliZ and FliY are not required for motility but may regulate sigma F activity, perhaps in response to a putative cell density signal that may be detected by FliY, a member of the bacterial extracellular solute-binding protein family 3.
我们克隆了大肠杆菌fliAZY操纵子，它包含fliA基因（替代sigma因子sigma F）以及两个新基因fliZ和fliY。对该操纵子的转录图谱分析显示有两个起始位点，其中一个之前有一个典型的依赖E sigma F的共有序列，并且在体内和体外表达均依赖sigma F。我们已经过量表达并纯化了sigma F，并证明它可以引导核心聚合酶作用于依赖E sigma F的启动子。运动性并不需要FliZ和FliY，但它们可能调节sigma F的活性，也许是对一种假定的细胞密度信号作出反应，该信号可能由细菌细胞外溶质结合蛋白家族3的成员FliY检测到。
