PROOFREADING-DEFECTIVE DNA-POLYMERASE-II INCREASES ADAPTIVE MUTATION IN ESCHERICHIA-COLI
PROOFREADING-DEFECTIVE DNA-POLYMERASE-II INCREASES ADAPTIVE MUTATION IN ESCHERICHIA-COLI
复制标题
DOI：
10.1073/pnas.92.17.7951
复制
发表时间：
1995-08-15
影响因子：
11.1
通讯作者：
GOODMAN, MF
中科院分区：
文献类型：
--
作者：
FOSTER, PL;GUDMUNDSSON, G;GOODMAN, MF
大肠杆菌PNA聚合酶（Pol）II在产生或避免突变中的作用通过用编码核酸外切酶缺陷突变体pol II（polBex 1）的基因替换染色体Pol II基因（polB（+））来研究。polBex 1等位基因增加适应性突变的附加体在乳糖选择下的非分裂细胞。Pol III抗突变体等位基因（dnaE 915）的存在将polB（+）细胞和缺失polB的细胞（polB Delta 1）中的适应性突变降低至野生型水平以下，表明Pol II和Pol III都在非分裂细胞中合成附加型DNA，但在野生型细胞中Pol III产生适应性突变。适应性突变主要是在短的均聚运行中发生的-1移码，并且在野生型、polB Delta 1和polBex 1菌株中相似。由Pol III和Pol II ex 1产生的突变通过mutHLS错配修复系统校正。
The role of Escherichia coli PNA polymerase (Pol) II in producing or avoiding mutations was investigated by replacing the chromosomal Pol II gene (polB(+)) by a gene encoding an exonuclease-deficient mutant pol II (polBex1). The polBex1 allele increased adaptive mutations on an episome in nondividing cells under lactose selection. The presence of a Pol III antimutator allele (dnaE915) reduced adaptive mutations in both polB(+) cells and cells deleted for polB (polB Delta 1) to below the wild type level, suggesting that both Pol II and pol III are synthesizing episomal DNA in nondividing cells but that in wild-type cells Pol III generates the adaptive mutations'. The adaptive mutations were mainly -1 frameshifts occurring in short homopolymeric runs and were similar in wild-type, polB Delta 1, and polBex1 strains. Mutations produced by both Pol III and Pol II ex1 were corrected by the mutHLS mismatch repair system.