Kannouche Patricia, Fernández de Henestrosa Antonio R, Coull Barry, Vidal Antonio E, Gray Colin, Zicha Daniel, Woodgate Roger, Lehmann Alan R
Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, Cancer Research UK London Research Institute, 44, Lincoln's Inn Fields, London WC2A 3PX, UK.
EMBO J. 2002 Nov 15;21(22):6246-56. doi: 10.1093/emboj/cdf618.
Y-family DNA polymerases can replicate past a variety of damaged bases in vitro but, with the exception of DNA polymerase eta (poleta), which is defective in xeroderma pigmentosum variants, there is little information on the functions of these polymerases in vivo. Here, we show that DNA polymerase iota (poliota), like poleta, associates with the replication machinery and accumulates at stalled replication forks following DNA-damaging treatment. We show that poleta and poliota foci form with identical kinetics and spatial distributions, suggesting that localization of these two polymerases is tightly co-ordinated within the nucleus. Furthermore, localization of poliota in replication foci is largely dependent on the presence of poleta. Using several different approaches, we demonstrate that poleta and poliota interact with each other physically and that the C-terminal 224 amino acids of poliota are sufficient for both the interaction with poleta and accumulation in replication foci. Our results provide strong evidence that poleta targets poliota to the replication machinery, where it may play a general role in maintaining genome integrity as well as participating in translesion DNA synthesis.
Y家族DNA聚合酶在体外能够跨越多种受损碱基进行复制，但是，除了在着色性干皮病变异型中存在缺陷的DNA聚合酶η（polη）之外，关于这些聚合酶在体内的功能几乎没有相关信息。在此，我们发现DNA聚合酶ι（polι）与polη一样，与复制机制相关联，并在DNA损伤处理后在停滞的复制叉处积累。我们发现polη和polι形成的焦点具有相同的动力学和空间分布，这表明这两种聚合酶在细胞核内的定位紧密协调。此外，polι在复制焦点中的定位很大程度上依赖于polη的存在。通过几种不同的方法，我们证明polη和polι在物理上相互作用，并且polι的C末端224个氨基酸对于与polη的相互作用以及在复制焦点中的积累都是足够的。我们的结果提供了强有力的证据，表明polη将polι靶向复制机制，在那里它可能在维持基因组完整性以及参与跨损伤DNA合成中发挥普遍作用。
