PCNA:POLD,POLE:RPA:RFC and FEN1 bind APEX1

PCNA-dependent long-patch base excision repair (BER) occurs during the S phase of the cell cycle when PCNA and associated DNA polymerases are available. PCNA is part of a large replicative complex that contains DNA polymerase delta or DNA polymerase epsilon, along with RPA and RFC complexes. When POLB (DNA polymerase beta) is unable to excise the oxidatively damaged AP residue (5'ddRP) at the APEX1-generated single strand break (SSB), PCNA and FEN1 are recruited to APEX1, where PCNA interacts with both APEX1 (Dianova et al. 2001) and FEN1 (Tom et al. 2000, Shibata and Nakamura 2002). PCNA-bound DNA polymerase delta complex (POLD) or DNA polymerase epsilon complex (POLE) displaces DNA polymerase beta (POLB) from the SSB (Klungland and Lindahl 1997).

PCNA依赖性长片段碱基切除修复（BER）发生在细胞周期的S期，此时PCNA及其相关的DNA聚合酶可用。PCNA是包含DNA聚合酶delta或DNA聚合酶epsilon、RPA和RFC复合物的大型复制复合体的一部分。当POLB（DNA聚合酶beta）无法切除由APEX1生成的单链断裂（SSB）处的氧化损伤的AP残基（5'ddRP）时，PCNA和FEN1被招募至APEX1，在此PCNA与APEX1（Dianova等，2001）和FEN1（Tom等，2000，Shibata和Nakamura，2002）相互作用。PCNA结合的DNA聚合酶delta复合物（POLD）或DNA聚合酶epsilon复合物（POLE）将DNA聚合酶beta（POLB）从SSB（Klungland和Lindahl，1997）中移除。