Fukui Tomoyuki, Yamauchi Kazumi, Muroya Taketo, Akiyama Masahiro, Maki Hisaji, Sugino Akio, Waga Shou
Department of Biochemistry and Molecular Biology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Genes Cells. 2004 Mar;9(3):179-91. doi: 10.1111/j.1356-9597.2004.00716.x.
DNA polymerases delta and epsilon (Poldelta and Polepsilon) are widely thought to be the major DNA polymerases that function in elongation during DNA replication in eukaryotic cells. However, the precise roles of these polymerases are still unclear. Here we comparatively analysed DNA replication in Xenopus egg extracts in which Poldelta or Polepsilon was immunodepleted. Depletion of either polymerase resulted in a significant decrease in DNA synthesis and accumulation of short nascent DNA products, indicating an elongation defect. Moreover, Poldelta depletion caused a more severe defect in elongation, as shown by sustained accumulation of both short nascent DNA products and single-stranded DNA gaps, and also by elevated chromatin binding of replication proteins that function more frequently during lagging strand synthesis. Therefore, our data strongly suggest the possibilities that Poldelta is essential for lagging strand synthesis and that this function of Poldelta cannot be substituted for by Polepsilon.
DNA聚合酶δ和ε（Poldelta和Polepsilon）被广泛认为是真核细胞DNA复制过程中负责延伸功能的主要DNA聚合酶。然而，这些聚合酶的确切作用仍不清楚。在此，我们对非洲爪蟾卵提取物中的DNA复制进行了比较分析，其中Poldelta或Polepsilon已被免疫去除。去除任何一种聚合酶都会导致DNA合成显著减少以及短新生DNA产物的积累，表明存在延伸缺陷。此外，Poldelta的去除导致延伸方面更严重的缺陷，这表现为短新生DNA产物和单链DNA缺口的持续积累，以及在滞后链合成过程中更频繁发挥作用的复制蛋白与染色质结合的增加。因此，我们的数据有力地表明，Poldelta对于滞后链合成至关重要，并且Poldelta的这一功能不能被Polepsilon替代。
