Furano A V, Wittel F P
Cell. 1976 May;8(1):115-22. doi: 10.1016/0092-8674(76)90192-6.
We have shown that the relA gene can affect the rates of synthesis of many nonribosomal proteins in E. coli. We used rel+ and relA strains that contain a temperature-sensitive valyl tRNA synthetase. Upon transfer from a permissive temperature (30degreesC) to a semi-resitrictive one (36.5degreesC), these strains continue to grow, although undergoing a partial deprivation of valyl tRNA, In the rel+ strain, the concentration of ppGpp increases immediately, and the accumulation of RNA ceases abruptly but temporarily. In contrast, in the relA strain, the concentration of ppGpp falls, whereas the rate of accumulation of RNA increases. As judged by gel electrophoresis, the rates at which individual polypeptides are synthesized by the strains after their transfer to 36.5degreesC depend to a large extent upon the allelic state of the relA gene. In both strains, the concentration of ppGpp changes soon enough to have altered the synthesis of some of the proteins by affecting the transcription of their genes.
我们已经证明，relA基因能够影响大肠杆菌中许多非核糖体蛋白的合成速率。我们使用了含有温度敏感型缬氨酰tRNA合成酶的rel⁺和relA菌株。当从允许温度（30℃）转移到半限制温度（36.5℃）时，这些菌株尽管经历了缬氨酰tRNA的部分缺失，但仍继续生长。在rel⁺菌株中，ppGpp的浓度立即增加，RNA的积累突然但暂时停止。相比之下，在relA菌株中，ppGpp的浓度下降，而RNA的积累速率增加。通过凝胶电泳判断，菌株转移到36.5℃后，各个多肽的合成速率在很大程度上取决于relA基因的等位基因状态。在这两种菌株中，ppGpp的浓度变化足够快，通过影响其基因的转录改变了一些蛋白质的合成。
