Bloom M, Skelly S, VanBogelen R, Neidhardt F, Brot N, Weissbach H
J Bacteriol. 1986 May;166(2):380-4. doi: 10.1128/jb.166.2.380-384.1986.
In Escherichia coli, the ability to elicit a heat shock response depends on the htpR gene product. Previous work has shown that the HtpR protein serves as a sigma factor (sigma 32) for RNA polymerase that specifically recognizes heat shock promoters (A.D. Grossman, J.W. Erickson, and C.A. Gross Cell 38:383-390, 1984). In the present study we showed that sigma 32 synthesized in vitro could stimulate the expression of heat shock genes. The in vitro-synthesized sigma 32 was found to be associated with RNA polymerase. In vivo-synthesized sigma 32 was also associated with RNA polymerase, and this polymerase (E sigma 32) could be isolated free of the standard polymerase (E sigma 70). E sigma 32 was more active than E sigma 70 with heat shock genes; however, non-heat-shock genes were not transcribed by E sigma 32. The in vitro expression of the htpR gene required E sigma 70 but did not require E sigma 32.
在大肠杆菌中，引发热休克反应的能力取决于htpR基因产物。先前的研究表明，HtpR蛋白作为RNA聚合酶的一种σ因子（σ32），可特异性识别热休克启动子（A.D.格罗斯曼、J.W.埃里克森和C.A.格罗斯，《细胞》38:383 - 390，1984年）。在本研究中，我们发现体外合成的σ32能够刺激热休克基因的表达。体外合成的σ32被发现与RNA聚合酶相关。体内合成的σ32也与RNA聚合酶相关，并且这种聚合酶（Eσ32）能够从标准聚合酶（Eσ70）中分离出来。Eσ32对热休克基因的活性比Eσ70更高；然而，非热休克基因不能被Eσ32转录。htpR基因的体外表达需要Eσ70，但不需要Eσ32。
