Syväoja J E
Department of Biochemistry, University of Oulu, Finland.
Bioessays. 1990 Nov;12(11):533-6. doi: 10.1002/bies.950121106.
DNA polymerase epsilon is a mammalian polymerase that has a tightly associated 3'----5' exonuclease activity. Because of this readily detectable exonuclease activity, the enzyme has been regarded as a form of DNA polymerase delta, an enzyme which, together with DNA polymerase alpha, is in all probability required for the replication of chromosomal DNA. Recently, it was discovered that DNA polymerase epsilon is both catalytically and structurally distinct from DNA polymerase delta. The most striking difference between the two DNA polymerases is that processive DNA synthesis by DNA polymerase delta is dependent on proliferating cell nuclear antigen (PCNA), a replication factor, while DNA polymerase epsilon is inherently processive. DNA polymerase epsilon is required at least for the repair synthesis of UV-damaged DNA. DNA polymerases are highly conserved in eukaryotic cells. Mammalian DNA polymerases alpha, delta and epsilon are counterparts of yeast DNA polymerases I, III and II, respectively. Like DNA polymerases I and III, DNA polymerase II is also essential for the viability of cells, which suggests that DNA polymerase II (and epsilon) may play a role in DNA replication.
DNA聚合酶ε是一种哺乳动物聚合酶，具有紧密相关的3'→5'核酸外切酶活性。由于这种易于检测到的核酸外切酶活性，该酶一直被视为DNA聚合酶δ的一种形式，DNA聚合酶δ与DNA聚合酶α一起，很可能是染色体DNA复制所必需的酶。最近，人们发现DNA聚合酶ε在催化和结构上都与DNA聚合酶δ不同。这两种DNA聚合酶之间最显著的差异在于，DNA聚合酶δ的持续性DNA合成依赖于增殖细胞核抗原（PCNA），一种复制因子，而DNA聚合酶ε本身就具有持续性。DNA聚合酶ε至少是紫外线损伤DNA修复合成所必需的。DNA聚合酶在真核细胞中高度保守。哺乳动物的DNA聚合酶α、δ和ε分别是酵母DNA聚合酶I、III和II的对应物。与DNA聚合酶I和III一样，DNA聚合酶II对细胞的生存能力也至关重要，这表明DNA聚合酶II（和ε）可能在DNA复制中发挥作用。
