大肠杆菌的spoT突变增加了缺失弱化子的组氨酸操纵子的表达。
Mutation spoT of Escherichia coli increases expression of the histidine operon deleted for the attenuator.
作者信息
Winkler M E, Zawodny R V, Hartman P E
出版信息
J Bacteriol. 1979 Sep;139(3):993-1000. doi: 10.1128/jb.139.3.993-1000.1979.
F'-episomes carrying the Salmonella typhimurium wild-type or attenuator-deleted histidine (his) operons were introduced into Escherichia coli strains containing relA or spoT single and double mutations known to affect guanosine 3'-diphosphate 5'-diphosphate (ppGpp) and guanosine 3'-triphosphate 5'-diphosphate (pppGpp) levels. Expression of the his operon and expression of the gene for 6-phosphogluconate dehydrogenase (gnd) were measured during balanced growth in amino acid-rich and minimal media. The data were consistent with the interpretation that ppGpp is a positive effector of his operon expression, whereas pppGpp is not an essential effector. The conclusion that his operon expression is maximally stimulated at a lower than maximum intracellular ppGpp concentration was further confirmed. Neither ppGpp nor pppGpp appeared to influence gnd gene expression. The metabolic regulation of the E. coli his operon was found to be similar to the ppGpp-meidated metabolic regulation of the S. typhimurium his operon.
将携带鼠伤寒沙门氏菌野生型或缺失弱化子的组氨酸（his）操纵子的F'附加体导入含有relA或spoT单突变和双突变的大肠杆菌菌株中，已知这些突变会影响鸟苷3'-二磷酸5'-二磷酸（ppGpp）和鸟苷3'-三磷酸5'-二磷酸（pppGpp）的水平。在富含氨基酸的培养基和基本培养基中平衡生长期间，测量了his操纵子的表达以及6-磷酸葡萄糖酸脱氢酶（gnd）基因的表达。这些数据与以下解释一致：ppGpp是his操纵子表达的正效应物，而pppGpp不是必需的效应物。进一步证实了his操纵子表达在低于最大细胞内ppGpp浓度时受到最大刺激的结论。ppGpp和pppGpp似乎都不影响gnd基因的表达。发现大肠杆菌his操纵子的代谢调控与鼠伤寒沙门氏菌his操纵子的ppGpp介导的代谢调控相似。
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