Specificity of Escherichia coli mutD and mutL mutator strains.
Specificity of Escherichia coli mutD and mutL mutator strains.
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DOI：
10.1016/0378-1119(90)90488-d
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发表时间：
1990-03
期刊：
影响因子：
3.5
通讯作者：
Te-hui Wu;Chester H. Clarke;M. Marinus
中科院分区：
文献类型：
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作者：
Te-hui Wu;Chester H. Clarke;M. Marinus
大肠杆菌的mutD和mutL基因产物分别参与DNA聚合酶III和DNA腺嘌呤MTase（Dam）依赖的错配修复的校对。我们使用质粒携带的噬菌体P22 mnt基因作为靶基因，以确定mutL 25和mutD 5菌株中产生的突变类型。在从mutL 25细胞中鉴定的60个突变中，52个是过渡突变，其中AT → GC亚群占主导地位（40/52）。大多数AT → GC突变发生在相同的三个位点（热点）。相比之下，发现颠换突变（76个中的47个）的频率约为mutD 5细菌转换（76个中的28个）的两倍。两个热点被确定，但在不同的网站比那些在mutL 25细胞。这些结果表明，DNA聚合酶III的校对功能主要修复潜在的颠换突变，而Dam依赖的错配修复纠正潜在的转换突变。
The products of themutDandmutLgenes ofEscherichia coliare involved in proofreading by DNA polymerase III and DNA adenine MTase (Dam)-dependent mismatch repair, respectively. We have used the plasmid-borne bacteriophage P22mntgene as a target to determine the types of mutations produced inmutL25andmutD5 strains. Of 60 mutations identified frommutL25 cells, 52 were transition mutations and of these the AT → GC subset predominated (40 out of 52). The majority of AT → GC mutations were found at the same three sites (hotspots). In contrast, transversion mutations (47 out of 76) were found about twice as frequently as transitions (28 out of 76) frommutD5 bacteria. Two hotspots were identified but at different sites than those in themutL25 cells. These results suggest that the proofreading function of DNA polymerase III primarily repairs potential transversion mutations while Dam-dependent mismatch repair rectifies potential transition mutations.