Delaney J M
Department of Microbiology and Immunology, College of Medicine, University of Arizona, Tucson 85724.
Genet Res. 1990 Feb;55(1):1-6. doi: 10.1017/s001667230002512x.
An adenyl cyclase deletion mutant (cya) of E. coli failed to exhibit a heat-shock response even after 30 min at 42 degrees C. Under these conditions, heat-shock protein synthesis was induced by 10 min in the wild-type strain. These results suggest that synthesis of heat-shock proteins in E. coli requires the cya gene. This hypothesis is supported by the finding that a presumptive cyclic AMP receptor protein (CRP) binding site exists within the promoter region of the E. coli htpR gene. In spite of the absence of heat-shock protein synthesis, when treated at 50 degrees C, the cya mutant is relatively more heat resistant than wild type. Furthermore, when heat shocked at 42 degrees C prior to exposure at 50 degrees C, the cya mutant developed thermotolerance. These results suggest that heat-shock protein synthesis is not essential for development of thermotolerance in E. coli.
大肠杆菌的腺苷酸环化酶缺失突变体（cya）即使在42℃下处理30分钟后也未表现出热休克反应。在这些条件下，野生型菌株在10分钟内诱导了热休克蛋白的合成。这些结果表明，大肠杆菌中热休克蛋白的合成需要cya基因。这一假设得到了以下发现的支持：在大肠杆菌htpR基因的启动子区域内存在一个假定的环磷酸腺苷受体蛋白（CRP）结合位点。尽管缺乏热休克蛋白的合成，但当在50℃下处理时，cya突变体比野生型相对更耐热。此外，当在50℃暴露之前于42℃进行热休克处理时，cya突变体产生了耐热性。这些结果表明，热休克蛋白的合成对于大肠杆菌耐热性的形成并非必不可少。
