Analyses of ultraviolet-induced focus formation of hREV1 protein
Analyses of ultraviolet-induced focus formation of hREV1 protein
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DOI：
10.1111/j.1365-2443.2006.00938.x
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发表时间：
2006-03-01
期刊：
影响因子：
2.1
通讯作者：
Takahashi, M
中科院分区：
文献类型：
--
作者：
Murakumo, Y;Mizutani, S;Takahashi, M
跨病灶 DNA 合成 (TLS) 是 DNA 损伤耐受机制之一，允许 DNA 损伤的细胞继续 DNA 复制。每种哺乳动物 Y 家族 DNA 聚合酶（Pol eta、Pol iota、Pol kappa 和 REV1）已被证明可以单独或与另一种酶在体外结合执行 TLS。最近，发现哺乳动物 REV1 的 C 端区域（人类共有 1251 个残基）与 Pol eta、Pol iota 和 Pol kappa 以及另一种 TLS 酶 Pol zeta 的 REV7 亚基相互作用。因此，有人提出 REV1 在体内 TLS 中发挥着关键作用。我们在这里描述了我们对人类 REV1 蛋白 (hREV1) 在未受损和紫外线 (UV) 照射的细胞中的定位的研究。哺乳动物细胞中异位表达的 hREV1 定位于细胞核，并在约 3% 的未受损细胞中表现出数十个微小的病灶。紫外线照射后，病灶形成细胞的百分比以时间和剂量依赖性方式显着增加。焦点的形成与紫外线引起的 DNA 损伤有关。有趣的是，虽然S期细胞中的hREV1焦点与PCNA焦点共定位，表明hREV1与复制机制相关，但hREV1焦点形成不仅在S期而且在S期外也观察到。此外，还发现UV照射后hREV1焦点的形成需要靠近C末端的区域(826-1178)。
Translesional DNA synthesis (TLS) is one of the DNA damage tolerance mechanisms that allow cells with DNA damage to continue DNA replication. Each of the mammalian Y-family DNA polymerases (Pol eta, Pol iota, Pol kappa, and REV1) has been shown to carry out TLS by itself or in combination with another enzyme in vitro. Recently, the C-terminal region of mammalian REV1 (the total 1251 residues in human) was found to interact with Pol eta, Pol iota, and Pol kappa, as well as with the REV7 subunit of another TLS enzyme, Pol zeta. Thus, it is proposed that REV1 plays a pivotal role in TLS in vivo. We here describe our study on the localization of human REV1 protein (hREV1) in nondamaged and ultraviolet (UV)-irradiated cells. Ectopically expressed hREV1 in mammalian cells was localized to the nucleus and exhibited dozens of tiny foci in approximately 3% of nondamaged cells. The percentage of focus-forming cells markedly increased after UV irradiation in a time- and dose-dependent manner. The focus formation was associated with UV-induced DNA damage. Interestingly, although the hREV1 foci in S-phase cells colocalized with PCNA foci, suggesting the association of hREV1 with the replication machinery, hREV1 focus formation was observed not only in the S phase but also outside S phase. Furthermore, it was found that the hREV1 focus formation after UV irradiation required a region near the C-terminal (826-1178).