DNA replication errors produced by the replicative apparatus of Escherichia coli
DNA replication errors produced by the replicative apparatus of Escherichia coli
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DOI：
10.1006/jmbi.1999.2802
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发表时间：
1999-06-18
影响因子：
5.6
通讯作者：
Maki, H
中科院分区：
文献类型：
--
作者：
Fujii, S;Akiyama, M;Maki, H
由于复制型DNA聚合酶的高保真度和所用单链模板DNA中预先存在的突变的高背景水平，很难检测在体外DNA合成过程中通过复制型DNA聚合酶产生的正向突变。利用oriC质粒DNA体外复制系统和rpsL正向突变试验，研究了大肠杆菌复制器催化DNA复制的保真度。在通过完全重构的系统进行DNA合成时，产物DNA中rpsL（-）突变的频率增加到1.9 × 10（-4），比模板DNA的背景水平高50倍。在体外产生的突变中，单碱基移码占主导地位，发生的模式类似于在错配修复缺陷型大肠杆菌中诱导的模式。大肠杆菌细胞，表明主要的复制错误是在相同核苷酸的运行滑动。DNA的大缺失和其他结构改变似乎也在复制装置的作用过程中被诱导。(C)北京：科学出版社.
It has been hard to detect forward mutations generated during DNA synthesis in vitro by replicative DNA polymerases, because of their extremely high fidelity and a high background level of pre-existing mutations in the single-stranded template DNA used. Using the oriC plasmid DNA replication in vitro system and the rpsL forward mutation assay, we examined the fidelity of DNA replication catalyzed by the replicative apparatus of Escherichia coli. Upon DNA synthesis by the fully reconstituted system, the frequency of rpsL(-) mutations in the product DNA was increased to 1.9 x 10(-4), 50-fold higher than the background level of the template DNA. Among the mutations generated in vitro, single-base frameshifts predominated and occurred with a pattern similar to those induced in mismatch-repair deficient E. coli cells, indicating that the major replication error was slippage at runs of the same nucleotide. Large deletions and other structural alterations of DNA appeared to be induced also during the action of the replicative apparatus. (C) 1999 Academic Press.