Brissette J L, Weiner L, Ripmaster T L, Model P
Rockefeller University, New York, NY 10021.
J Mol Biol. 1991 Jul 5;220(1):35-48. doi: 10.1016/0022-2836(91)90379-k.
We describe a new Escherichia coli operon, the phage shock protein (psp) operon, which is induced in response to heat, ethanol, osmotic shock and infection by filamentous bacteriophages. The operon includes at least four genes: pspA, B, C and E. PspA associates with the inner membrane and has the heptad repeats characteristic of proteins that can form coiled coils. The operon encodes a factor that activates psp expression, and deletion analyses indicate that this protein is PspC; PspC is predicted to possess a leucine zipper, a motif present in many eukaryotic transcription factors. The pspE gene is expressed in response to stress as part of the operon, but is also transcribed from its own promoter under normal conditions. In vitro studies suggest that PspA and C are modified in vivo. Expression of the psp genes does not require the heat shock sigma factor, sigma32. The increased duration of psp induction in a sigma32 mutant suggests that a product (or products) of the heat shock response down-regulates expression of the operon.
我们描述了一种新的大肠杆菌操纵子，即噬菌体休克蛋白（psp）操纵子，它在受到热、乙醇、渗透压休克以及丝状噬菌体感染时被诱导。该操纵子至少包括四个基因：pspA、B、C和E。PspA与内膜结合，具有可形成卷曲螺旋的蛋白质所特有的七肽重复序列。该操纵子编码一种激活psp表达的因子，缺失分析表明这种蛋白质是PspC；预计PspC具有亮氨酸拉链，这是许多真核转录因子中存在的一种基序。pspE基因作为操纵子的一部分在应激时表达，但在正常条件下也从其自身启动子转录。体外研究表明PspA和C在体内被修饰。psp基因的表达不需要热休克σ因子σ32。在σ32突变体中psp诱导持续时间的增加表明热休克反应的一种（或多种）产物下调了该操纵子的表达。
