Aoufouchi S, Flatter E, Dahan A, Faili A, Bertocci B, Storck S, Delbos F, Cocea L, Gupta N, Weill J C, Reynaud C A
INSERM U373, Faculté de Médecine Necker-Enfants Malades, Université Paris V, 156 rue de Vaugirard, 75730 Paris cedex 15, France.
Nucleic Acids Res. 2000 Sep 15;28(18):3684-93. doi: 10.1093/nar/28.18.3684.
We describe here two novel mouse and human DNA polymerases: one (pol lambda) has homology with DNA polymerase beta while the other one (pol mu) is closer to terminal deoxynucleotidyltransferase. However both have DNA polymerase activity in vitro and share similar structural organization, including a BRCT domain, helix-loop-helix DNA-binding motifs and polymerase X domain. mRNA expression of pol lambda is highest in testis and fetal liver, while expression of pol mu is more lymphoid, with highest expression both in thymus and tonsillar B cells. An unusually large number of splice variants is observed for the pol mu gene, most of which affect the polymerase domain. Expression of mRNA of both polymerases is down-regulated upon treatment by DNA damaging agents (UV light, gamma-rays or H(2)O(2)). This suggests that their biological function may differ from DNA translesion synthesis, for which several DNA polymerase activities have been recently described. Possible functions are discussed.
我们在此描述了两种新型的小鼠和人类DNA聚合酶:一种(聚合酶λ)与DNA聚合酶β具有同源性,而另一种(聚合酶μ)则更接近末端脱氧核苷酸转移酶。然而,两者在体外均具有DNA聚合酶活性,并具有相似的结构组织,包括一个BRCT结构域、螺旋-环-螺旋DNA结合基序和聚合酶X结构域。聚合酶λ的mRNA在睾丸和胎儿肝脏中表达最高,而聚合酶μ的表达则更偏向于淋巴组织,在胸腺和扁桃体B细胞中表达最高。聚合酶μ基因存在异常大量的剪接变体,其中大多数影响聚合酶结构域。经DNA损伤剂(紫外线、γ射线或H₂O₂)处理后,两种聚合酶的mRNA表达均下调。这表明它们的生物学功能可能不同于最近描述的几种DNA聚合酶活性的DNA跨损伤合成。文中讨论了可能的功能。