A weak adaptive response to alkylation damage in Salmonella typhimurium
A weak adaptive response to alkylation damage in Salmonella typhimurium
复制标题
鼠伤寒沙门氏菌对烷基化损伤的弱适应性反应
DOI：
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发表时间：
1991
影响因子：
3.2
通讯作者：
Barbara Sedgwick
中科院分区：
文献类型：
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作者：
Patrick Vaughan;Barbara Sedgwick
在几种肠细菌中观察到对烷基化损伤的有效适应性反应，包括产气克雷伯氏菌、宋内志贺菌、鲍氏志贺菌、碱性埃希氏菌、赫氏埃希氏菌和费格森埃希氏菌。增加O 6-甲基鸟嘌呤-DNA和甲基磷酸三酯-DNA甲基转移酶的活性与诱导的39-kDa的蛋白质识别的单克隆抗体对大肠杆菌Ada蛋白。诱导甲基转移酶活性在产气荚膜杆菌和中间柠檬酸杆菌中也观察到类似的结果，尽管不存在抗原交叉反应物质。弱诱导一个39 kDa的蛋白免疫相关的E。大肠杆菌Ada蛋白在鼠伤寒沙门氏菌中存在。该蛋白由克隆的S.鼠伤寒ada基因是一个有活性的甲基转移酶，它能像大肠杆菌一样有效地修复DNA中的O 6-甲基鸟嘌呤和甲基磷酸三酯。coli Ada蛋白。然而，弱诱导的39-kDa蛋白在S.没有检测到鼠伤寒沙门氏菌，这显然是因为它是自身甲基化的，因此在适应性N-甲基-N-硝基-N-亚硝基胍预处理过程中失活。相比之下，E. coli ada基因在S.鼠伤寒沙门氏菌，并观察到高甲基转移酶活性。我们的结论是，S.鼠伤寒沙门氏菌是由于自身甲基化蛋白对其ADA基因的弱转录激活而产生的。
An efficient adaptive response to alkylation damage was observed in several enterobacterial species, including Klebsiella aerogenes, Shigella sonnei, Shigella boydii, Escherichia alkalescens, Escherichia hermanii, and Escherichia fergusonii. Increased O6-methylguanine-DNA and methylphosphotriester-DNA methyltransferase activities correlated with the induction of a 39-kDa protein recognized by monoclonal antibodies raised against the Escherichia coli Ada protein. Induced methyltransferase activities were similarly observed in Aerobacter aerogenes and Citrobacter intermedius, although no antigenically cross-reacting material was present. Weak induction of a 39-kDa protein immunologically related to the E. coli Ada protein occurred in Salmonella typhimurium. This protein encoded by the cloned S. typhimurium ada gene was shown to be an active methyltransferase which repaired O6-methylguanine and methylphosphotriesters in DNA as efficiently as did the E. coli Ada protein. However, the mehtyltransferase activity of the weakly induced 39-kDa protein in S. typhimurium was not detected, apparently because it was self-methylated and thus inactivated during the adaptive N-methyl-N-nitro-N-nitrosoguanidine pretreatment. In contrast, the E. coli ada gene on a low-copy-number plasmid was efficiently induced in S. typhimurium, and high methyltransferase activities were observed. We concluded that the inefficient induction of the adaptive response in S. typhimurium results from weak transcriptional activation of its ada gene by the self-methylated protein.