Exonuclease I of Saccharomyces cerevisiae functions in mitotic recombination in vivo and in vitro
Exonuclease I of Saccharomyces cerevisiae functions in mitotic recombination in vivo and in vitro
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DOI：
10.1128/mcb.17.5.2764
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发表时间：
1997-05-01
影响因子：
5.3
通讯作者：
Symington, LS
中科院分区：
文献类型：
--
作者：
Fiorentini, P;Huang, KN;Symington, LS
我们先前描述了具有重叠同源末端的线性DNA分子之间体外重组所需的5 '-3'外切核酸酶。这种核酸外切酶，称为核酸外切酶I（Exo I），已经从植物生长的细胞中纯化超过300倍，并与42-kDa多肽共纯化。该活性是非进行性的，并且优先作用于双链DNA。其生化特性与粟酒裂殖酵母I.从含有酿酒酵母EXO 1基因突变的细胞制备的提取物，该基因是S.粟酒裂殖酵母exo 1具有降低的体外重组活性，并且当分级分离时，发现缺乏对应于5 ′-3 ′核酸外切酶的活性峰。通过测量含有直接复制的突变体ade 2基因的exo 1菌株中的重组率来确定EXO 1对体内重组的作用，并且EXO 1的重组率降低了6倍。这些结果表明，EXO 1是需要在体内和体外重组，除了其先前确定的错配修复的作用。
We previously described a 5'-3' exonuclease required for recombination in vitro between linear DNA molecules with overlapping homologous ends. This exonuclease, referred to as exonuclease I (Exo I), has been purified more than 300-fold from vegetatively grown cells and copurifies with a 42-kDa polypeptide. The activity is nonprocessive and acts preferentially on double-stranded DNA. The biochemical properties are quite similar to those of Schizosaccharomyces pombe fro I. Extracts prepared from cells containing a mutation of the Saccharomyces cerevisiae EXO1 gene, a homolog of S. pombe exo1, had decreased in vitro recombination activity and when fractionated were found to lack the peak of activity corresponding to the 5'-3' exonuclease. The role of EXO1 on recombination in vivo was determined by measuring the rate of recombination in an exo1 strain containing a direct duplication of mutant ade2 genes and was reduced sixfold. These results indicate that EXO1 is required for recombination in vivo and in vitro in addition to its previously identified role in mismatch repair.