Longley M J, Pierce A J, Modrich P
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.
J Biol Chem. 1997 Apr 18;272(16):10917-21. doi: 10.1074/jbc.272.16.10917.
HeLa nuclear extract was resolved into a depleted fraction incapable of supporting mismatch repair in vitro, and repair activity was restored upon the addition of a purified fraction isolated from HeLa cells by in vitro complementation assay. The highly enriched complementing activity copurified with a DNA polymerase, and the most pure fraction contained DNA polymerase delta but was free of detectable DNA polymerases alpha and epsilon. Calf thymus DNA polymerase delta also fully restored mismatch repair to the depleted extract, indicating DNA polymerase delta is required for mismatch repair in human cells. However, due to the presence of DNA polymerases alpha and epsilon in the depleted extract, potential involvement of one or both of these activities in the reaction cannot be excluded.
将HeLa细胞核提取物分离成在体外无法支持错配修复的耗尽组分，通过体外互补试验添加从HeLa细胞中分离出的纯化组分后，修复活性得以恢复。高度富集的互补活性与一种DNA聚合酶共纯化，最纯的组分含有DNA聚合酶δ，但未检测到DNA聚合酶α和ε。小牛胸腺DNA聚合酶δ也能完全恢复耗尽提取物中的错配修复，表明DNA聚合酶δ是人类细胞错配修复所必需的。然而，由于耗尽提取物中存在DNA聚合酶α和ε，不能排除这两种活性中的一种或两种在反应中的潜在参与。
