DNA polymerases ν and θ are required for efficient immunoglobulin V gene diversification in chicken
DNA polymerases ν and θ are required for efficient immunoglobulin V gene diversification in chicken
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DOI：
10.1083/jcb.200912012
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发表时间：
2010-07-28
影响因子：
7.8
通讯作者：
Takeda, Shunichi
中科院分区：
文献类型：
--
作者：
Kohzaki, Masaoki;Nishihara, Kana;Takeda, Shunichi
鸡DT 40 B淋巴细胞系通过跨损伤DNA合成依赖性点突变（IG超突变）和同源重组（HR）依赖性IG基因转换使其免疫球蛋白（IG）V基因多样化。A家族DNA聚合酶Pol nu和Pol theta的易错生化特性使我们探索这些聚合酶在DT 40细胞中IG基因多样化中的作用。尽管POLN-/-/POLQ（-/-），但两种聚合酶的破坏导致IG基因转换事件的显著减少。细胞在HR介导的DNA修复中没有表现出明显的缺陷，如对喜树碱的敏感性没有增加所示。Pol eta以前也与IG基因转换有关。我们证明了一个POLH-/-/POLN-/-/POLQ（-/-）。三重突变体显示无IG基因转换和降低的IG超突变。总之，这些数据定义了Pol nu和Pol theta在重组中的作用，并表明与IG基因转换相关的DNA合成由三种专门的DNA聚合酶负责。
The chicken DT40 B lymphocyte line diversifies its immunoglobulin (Ig) V genes through translesion DNA synthesis-dependent point mutations (Ig hyper-mutation) and homologous recombination (HR)-dependent Ig gene conversion. The error-prone biochemical characteristic of the A family DNA polymerases Pol nu and Pol theta led us to explore the role of these polymerases in Ig gene diversification in DT40 cells. Disruption of both polymerases causes a significant decrease in Ig gene conversion events, although POLN-/-/POLQ(-/-). cells exhibit no prominent defect in HR-mediated DNA repair, as indicated by no increase in sensitivity to camptothecin. Pol eta has also been previously implicated in Ig gene conversion. We show that a POLH-/-/POLN-/-/POLQ(-/-). triple mutant displays no Ig gene conversion and reduced Ig hyper-mutation. Together, these data define a role for Pol nu and Pol theta in recombination and suggest that the DNA synthesis associated with Ig gene conversion is accounted for by three specialized DNA polymerases.