A new class of mutants in DNA polymerase I that affects gene transposition.
A new class of mutants in DNA polymerase I that affects gene transposition.
复制标题
DNA 聚合酶 I 中影响基因转座的一类新突变体。
DOI：
10.1016/0022-2836(82)90429-6
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发表时间：
1982
影响因子：
5.6
通讯作者：
Clements,M
中科院分区：
文献类型：
--
作者：
Syvanen,M;Hopkins,JD;Clements,M
大肠杆菌K12突变体在转座子Tn5和Tn10以及插入序列IS1和IS5的转座上都存在缺陷。除了转位缺陷外，突变体对甲基甲烷磺酸盐和紫外光也很敏感，不能生长噬菌体，缺少DNA聚合酶I的聚合活性和5 ‘−3 ’外切酶活性，表明突变在该酶的结构基因上。我们将突变等位基因命名为pola34。与该突变体相关的所有特性都与已知与ola相关的标记共转导。此外，对甲基甲烷磺酸盐抗性的突变体也恢复了Tn5、IS1和IS5的正常转位频率。利用二倍体pola34 / pola进行的互补试验表明，对甲基甲烷磺酸盐的敏感性和转位缺陷对野生型是隐性的。pola34的一些复归物（称为pola34spa）恢复对甲基甲烷磺酸盐和紫外线的抗性，部分恢复聚合酶和5 ‘−3 ’外切酶活性，但不恢复转位。因此，我们得出结论，在转位中既不需要聚合酶活性也不需要5 ‘−3 ’外切酶活性，而是需要DNA聚合酶I的一些其他特性。
A mutant ofEscherichia colistrain K12 is defective in transposition of both the transposons Tn5 and Tn10 and the insertion sequences IS1 and IS5. In addition to the defect in transposition, the mutant is also sensitive to methylmethane sulfonate and ultraviolet light, does not grow phage lambdaredand is missing the polymerizing activity and the 5′−3′ exonuclease activity of DNA polymerase I, indicating that the mutation is in the structural gene for this enzyme. We have designated the mutant allele aspolA34. All of the properties associated with this mutant cotransduce with a marker known to be linked topolA. Furthermore, revertants of the mutant to methylmethane sulfonate resistance also regain the normal transposition frequencies of Tn5, IS1 and IS5. Complementation tests using the diploidpolA34/polAshow that the sensitivity to methylmethane sulfonate, and the defect in transposition is recessive to the wild-type. Some revertants ofpolA34 (calledpolA34spa) restore resistance to methylmethane sulfonate and u.v. and partially restore the polymerase and 5′−3′ exonuclease activity but do not restore transposition. Thus we conclude that neither the polymerase activity nor the 5′−3′ exonuclease activity are required in transposition, but rather some other property of DNA polymerase I is needed.