Gross C A, Blattner F R, Taylor W E, Lowe P A, Burgess R R
Proc Natl Acad Sci U S A. 1979 Nov;76(11):5789-93. doi: 10.1073/pnas.76.11.5789.
A transducing phage has been isolated with codes for the sigma subunit of Escherichia coli RNA polymerase. Transducing phage were selected from E. coli shotgun collections of HindIII or Sac I fragments cloned into Charon 25, a new bacteriophage lambda vector that is capble of forming lyosogens at high temperature. Transduction of an E. coli strain carrying a temperature-sensitive mutation in the sigma gene was used for the selection. The positions of restriction sites for Sac I, HindIII, Xho I, Bgl II, and Kpn I in the cloned bacterial DNA segments were determined. Phage containing the HindIII fragment complement both primase (dnaG) and sigma (rpoD) whereas those containing the Sac I fragment complement only sigma. Results of analyses of the proteins made both in vivo after infection of UV-irradiated cells and in vitro in a coupled transcription/translation system suggest that a Sac I site separates the promoter for sigma from the sigma structural gene. The direction of transcription of sigma was determined to be clockwise with respect to the E. coli genetic map.
已分离出一种携带大肠杆菌RNA聚合酶σ亚基编码的转导噬菌体。转导噬菌体是从克隆到Charon 25（一种能够在高温下形成溶原菌的新型λ噬菌体载体）中的HindIII或Sac I片段的大肠杆菌鸟枪法文库中筛选出来的。利用携带σ基因温度敏感突变的大肠杆菌菌株的转导进行筛选。确定了克隆的细菌DNA片段中Sac I、HindIII、Xho I、Bgl II和Kpn I的限制性酶切位点位置。含有HindIII片段的噬菌体可互补引发酶（dnaG）和σ（rpoD），而含有Sac I片段的噬菌体仅互补σ。对紫外线照射细胞感染后体内产生的蛋白质以及体外偶联转录/翻译系统中产生的蛋白质的分析结果表明，Sac I位点将σ的启动子与σ结构基因分开。相对于大肠杆菌遗传图谱，确定σ的转录方向为顺时针。
