Evidence for interplay among yeast replicative DNA polymerases alpha, delta and epsilon from studies of exonuclease and polymerase active site mutations.
Evidence for interplay among yeast replicative DNA polymerases alpha, delta and epsilon from studies of exonuclease and polymerase active site mutations.
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DOI：
10.1186/1741-7007-2-11
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发表时间：
2004-05-26
期刊：
影响因子：
5.4
通讯作者：
Kunkel TA
中科院分区：
文献类型：
--
作者：
Pavlov YI;Maki S;Maki H;Kunkel TA
DNA聚合酶ε（Pol ε）是酵母细胞S期复制、DNA损伤修复和检查点控制的关键酶。导致Pol ε活性位点中酪氨酸变为丙氨酸的Pol 2-Y831 A突变不会引起生长缺陷，并赋予在错配修复缺陷型菌株中通常轻微但强烈的增变子表型。在这里，我们调查的增变效应的机制负责。纯化的四亚基Y831 A Pol ε比野生型Pol ε将更多的脱氧核苷三磷酸转化为脱氧核苷一磷酸，这表明聚合酶和核酸外切酶活性位点之间的配位发生了改变。如在具有pol 2-Y831 A，4双突变的单倍体菌株中所测量的，pol 2-Y831 A突变抑制了外切核酸酶活性位点中的pol 2 -4突变的增变因子效应，该增变因子效应消除了Pol ε的校正。二倍体菌株中突变率的分析揭示了pol 2-Y831 A等位基因对pol 2 -4是隐性的。此外，pol 2 -4突变与Pol δ和Pol α中的活性位点增变因子突变组合的菌株的突变率表明Pol ε可以校正Pol α和Pol δ在体内复制期间的某些错误。我们的数据表明，Pol ε中的Y831 A替换降低了复制保真度及其在染色体复制中的参与，但没有消除对生存力至关重要的额外功能。这表明其他聚合酶可以取代聚合酶ε的某些功能。
DNA polymerase ε (Pol ε) is essential for S-phase replication, DNA damage repair and checkpoint control in yeast. A pol2-Y831A mutation leading to a tyrosine to alanine change in the Pol ε active site does not cause growth defects and confers a mutator phenotype that is normally subtle but strong in a mismatch repair-deficient strain. Here we investigate the mechanism responsible for the mutator effect. Purified four-subunit Y831A Pol ε turns over more deoxynucleoside triphosphates to deoxynucleoside monophosphates than does wild-type Pol ε, suggesting altered coordination between the polymerase and exonuclease active sites. The pol2-Y831A mutation suppresses the mutator effect of the pol2-4 mutation in the exonuclease active site that abolishes proofreading by Pol ε, as measured in haploid strain with the pol2-Y831A,4 double mutation. Analysis of mutation rates in diploid strains reveals that the pol2-Y831A allele is recessive to pol2-4. In addition, the mutation rates of strains with the pol2-4 mutation in combination with active site mutator mutations in Pol δ and Pol α suggest that Pol ε may proofread certain errors made by Pol α and Pol δ during replication in vivo. Our data suggest that Y831A replacement in Pol ε reduces replication fidelity and its participation in chromosomal replication, but without eliminating an additional function that is essential for viability. This suggests that other polymerases can substitute for certain functions of polymerase ε.
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影响因子：
3.5
作者：
HOVLAND, P;FLICK, J;SCLAFANI, RA
通讯作者：
SCLAFANI, RA
影响因子：
5.6
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Karthikeyan, R;Vonarx, EJ;Kunz, BA
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2.1
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4.8
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Sugino, A
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4.8
作者：
Matsuda, T;Berg, BJV;Kunkel, TA
通讯作者：
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