RecQ4 Facilitates UV Light-induced DNA Damage Repair through Interaction with Nucleotide Excision Repair Factor Xeroderma Pigmentosum Group A (XPA)
RecQ4 Facilitates UV Light-induced DNA Damage Repair through Interaction with Nucleotide Excision Repair Factor Xeroderma Pigmentosum Group A (XPA)
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DOI：
10.1074/jbc.m801928200
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发表时间：
2008-10-24
影响因子：
4.8
通讯作者：
Luo, Jianyuan
中科院分区：
文献类型：
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作者：
Fan, Wei;Luo, Jianyuan
RECQL4 解旋酶基因的突变与 Rothmund-Thomson 综合征有关，该综合征的特点是基因组不稳定、癌症易感性和过早衰老。为了更好地确定 RecQ4 蛋白的细胞功能，我们研究了用不同 DNA 损伤剂（包括紫外线照射、4-硝基喹啉 1-氧化物、喜树碱、依托泊苷、羟基脲和 H2O2）处理细胞后 RecQ4 的亚细胞定位。我们发现 RecQ4 专门响应紫外线照射和 4-硝基喹啉 1-氧化物而形成离散的核灶。我们证明，功能性 RecQ4 是有效去除紫外线损伤所必需的，并且可以挽救 RecQ4 缺陷的 Rothmund-Thomson 综合征细胞的紫外线敏感性。此外，紫外线处理还导致人类细胞中 RecQ4 和着色性干皮病 A 组形成的核灶共定位。一致的是，RecQ4可以直接与着色性干皮病A组相互作用，并且这种相互作用受到紫外线照射的刺激。通过将全细胞提取物分级为细胞质、可溶性细胞核和染色质结合部分，我们观察到 RecQ4 蛋白在紫外线照射下与染色质结合更紧密。综上所述，我们的研究结果表明 RecQ4 在修复人类细胞中紫外线诱导的 DNA 损伤中发挥着重要作用。
Mutations in the RECQL4 helicase gene have been linked to Rothmund-Thomson syndrome, which is characterized by genome instability, cancer susceptibility, and premature aging. To better define the cellular function of the RecQ4 protein, we investigated the subcellular localization of RecQ4 upon treatment of cells with different DNA-damaging agents including-UV irradiation, 4-nitroquinoline 1-oxide, camptothecin, etoposide, hydroxyurea, and H2O2. We found that RecQ4 formed discrete nuclear foci specifically in response to UV irradiation and 4-nitroquinoline 1-oxide. We demonstrated that functional RecQ4 was required for the efficient removal of UV lesions and could rescue UV sensitivity of RecQ4-deficient Rothmund-Thomson syndrome cells. Furthermore, UV treatment also resulted in the colocalization of the nuclear foci formed with RecQ4 and xeroderma pigmentosum group A in human cells. Consistently, RecQ4 could directly interact with xeroderma pigmentosum group A, and this interaction was stimulated by UV irradiation. By fractionating whole cell extracts into cytoplasmic, soluble nuclear, and chromatin-bound fractions, we observed that RecQ4 protein bound more tightly to chromatin upon UV irradiation. Taken together, our findings suggest a role of RecQ4 in the repair of UV-induced DNA damages in human cells.