Straus D B, Walter W A, Gross C A
Nature. 1987;329(6137):348-51. doi: 10.1038/329348a0.
Cells subjected to a heat shock, or a variety of other stresses increase the synthesis of a set of proteins, known as heat shock proteins. This response is apparently universal, occurring in the entire range from bacterial to mammalian cells. In Escherichia coli heat shock protein synthesis transiently increases following a shift from 30 degrees C to 42 degrees C as a result of changes in transcription initiation at heat shock promoters. Heat shock promoters are recognized by RNA polymerase containing a sigma factor of relative molecular mass (Mr) 32,000 (32K) E sigma 32 and not E sigma 70, the major form of RNA polymerase holoenzyme. To determine whether changes in the concentration of sigma 32 regulate this response, we measured the amount of sigma 32 before and after shift to high temperature and found that it increased transiently during heat shock as a result of changes in sigma 32 synthesis and stability. Our results indicate that sigma 32 is directly responsible for regulation of the heat shock response.
受到热休克或其他各种应激的细胞会增加一组称为热休克蛋白的蛋白质的合成。这种反应显然是普遍存在的，从细菌到哺乳动物细胞都有发生。在大肠杆菌中，从30摄氏度转移到42摄氏度后，热休克蛋白的合成会短暂增加，这是由于热休克启动子处转录起始的变化所致。热休克启动子由含有相对分子质量（Mr）为32,000（32K）的σ因子Eσ32的RNA聚合酶识别，而不是由RNA聚合酶全酶的主要形式Eσ70识别。为了确定σ32浓度的变化是否调节这种反应，我们测量了转移到高温前后σ32的量，发现由于σ32合成和稳定性的变化，它在热休克期间短暂增加。我们的结果表明，σ32直接负责热休克反应的调节。
