Changes of DNA supercoiling in Escherichia coli induced by stress

我们以前报道过大肠杆菌的质粒DNA在细胞暴露于压力时松弛。在这项研究中，我们检测了在DNA回转酶抑制剂存在下sigma 32的稳定性和合成。结果表明，抑制剂稳定了sigma 32，刺激了蛋白的合成。我们还发现，在DNA依赖性蛋白合成的体外系统中，DNA松弛刺激了simga 32的合成。综上所述，我们得出结论，DNA松弛诱导细胞中sigman 32的稳定性和合成。我们认为细胞内DNA超卷曲的变化是诱导热休克蛋白的关键信号。

We previously reported that plasmid DNA in Escherichia coli relaxd when cells were exposed to stress. In this study, we examined stability and synthesis of sigma 32 in the presence of inhibitors of DNA gyrase.The result showed that the inhibitors stabilized sigma 32, and stimulated the synsthsis of the protein. We also showed that DNA relaxation stimulated synthesi of simga 32 in an in vitor system of DNA-dependent protein synthesis. Taken together, we conclude that DNA relaxation induces stability and synthesis of sigman 32 in cells. We propose that changes of DNA supercoiling in cells is a key signal for induction of heat shock proteins.