Plasmid expression of mutS, -L and/or -H gene in Escherichia coli dam cells results in strains that display reduced mutation frequency
Plasmid expression of mutS, -L and/or -H gene in Escherichia coli dam cells results in strains that display reduced mutation frequency
复制标题
DOI：
10.1016/j.mrfmmm.2007.07.006
复制
发表时间：
2008-01-01
影响因子：
2.3
通讯作者：
Barra, Jose L.
中科院分区：
文献类型：
--
作者：
Jacquelin, Daniela K.;Martina, Mariana A.;Barra, Jose L.
大肠杆菌dam细胞具有主动但非定向的错配修复系统;因此，MutSLH复合物在错配碱基对处的组装可导致MutH介导的两条DNA链中GATC位点的切割。在dam细胞中发生的一部分复制错误上的未配对双链断裂可能导致细胞死亡，从而从群体中选择性地消除这些推定的突变体。我们证明了E.用含有mutS、mutL或mutH基因的质粒转化的大肠杆菌dam细胞显示出比亲本dam菌株低3 - 8倍的突变频率，这是由于增加的错配刺激的细胞杀伤。转化的菌株也更容易被碱基类似物2-氨基嘌呤杀死。然而，dam和dam转化细胞具有相似的复制时间、活/死细胞比例和形态。(c)2007 Elsevier B. V.保留所有权利。
Escherichia coli dam cells have an active but non-directed mismatch repair system; therefore, assembly of MutSLH complex at a mismatched base pair can result in MutH-mediated cleavage of GATC sites in both DNA strands. Unpaired double-strand breaks on a fraction of the replication errors occurring in dam cells presumably cause cell death, selectively eliminating these putative mutants from the population. We show that E. coli dam cells transformed with plasmids containing either the mutS, mutL or mutH gene display a mutation frequency three to eight times lower than that of the parental dam strain, due to increased mismatch- stimulated cell killing. Transformed strains are also more susceptible to killing by the base analogue 2-aminopurine. However, dam and dam transformed cells have similar duplication time, proportion of live/dead cells and morphology. (c) 2007 Elsevier B.V. All rights reserved.