Intracellular cyclic AMP concentration is decreased in Salmonella typhimurium fur mutants
Intracellular cyclic AMP concentration is decreased in Salmonella typhimurium fur mutants
复制标题
DOI：
10.1099/00221287-148-4-1039
复制
发表时间：
2002-04-01
期刊：
影响因子：
2.8
通讯作者：
Barbé, J
中科院分区：
文献类型：
--
作者：
Campoy, S;Jara, M;Barbé, J
已知Fur蛋白负调节不同细菌物种（包括鼠伤寒沙门氏菌）中的铁摄取系统。在这项研究中，它已被证明，细胞内的浓度环腺苷酸（cAMP）是较低的敲除S。鼠伤寒沙门氏菌皮毛突变株的比例高于野生型菌株。据此，两个cAMP调节基因，如pepE（编码α-乙酰氨基二肽酶）和大肠杆菌lac操纵子的表达在S.鼠伤寒皮毛细胞与野生型细胞相比。在编码环状3 '，5'-cAMP磷酸二酯酶的cpdA中引入额外的突变，恢复了S.鼠伤寒皮毛突变体。同样，pepE和E. coli lac操纵子在S.鼠伤寒fur cpdA双突变体和野生型菌株。此外，这些结果还表明，S。鼠伤寒Fur蛋白正调节支配鞭毛调节子的flhD主操纵子的表达。该阳性对照必须通过S.鼠伤寒沙门氏菌Fur蛋白与flhD启动子结合，如该启动子在Fur滴定测定中测试为阳性的事实所示。
It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial species, including Salmonella typhimurium. In this study it has been shown that the intracellular concentration of cyclic AMP (cAMP) is lower in a knockout S. typhimurium fur mutant than in the wild-type strain. According to this, the expression of two cAMP-regulated genes, such as pepE (encoding an alpha-aspartyl dipeptidase) and the Escherichia coli lac operon, is decreased in S. typhimurium fur cells in comparison with wild-type cells. Introduction of an additional mutation in cpdA, encoding a cyclic 3',5'-cAMP phosphodiesterase, recovers wild-type intracellular cAMP concentration in the S. typhimurium fur mutant. Likewise, expression of pepE and the E. coli lac operon was the same in the S. typhimurium fur cpdA double mutant and the wild-type strain. Moreover, these results also demonstrate that the S. typhimurium Fur protein positively regulates the expression of the flhD master operon governing the flagellar regulon. This positive control must be mediated by binding of the S. typhimurium Fur protein to the flhD promoter as indicated by the fact that this promoter tests positive in a Fur titration assay.