Decreased gene expression responsible for post-ultraviolet DNA repair synthesis in aging: A possible mechanism of age-related reduction in DNA repair capacity
Decreased gene expression responsible for post-ultraviolet DNA repair synthesis in aging: A possible mechanism of age-related reduction in DNA repair capacity
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DOI：
10.1111/j.0022-202x.2004.23591.x
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发表时间：
2005-02-01
影响因子：
6.5
通讯作者：
Inoue, S
中科院分区：
文献类型：
--
作者：
Takahashi, Y;Moriwaki, SI;Inoue, S
紫外线（UV）后DNA修复能力的降低与衰老有关。为了明确这种变化的机制，我们采用宿主细胞再激活（HCR）法和环丁烷嘧啶二聚体和嘧啶-嘧啶（6-4）光产物ELISA法检测了不同年龄健康供体皮肤成纤维细胞的DNA修复能力。在HCR试验中，来自老年供体的细胞在恢复被紫外线损伤的转染报告DNA的能力方面表现出明显的下降。相比之下，在ELISA中，去除DNA损伤的能力随着年龄的增长而下降。这些结果表明，在核苷酸切除修复（NER）中，年龄敏感步骤发生在损伤切除后。多组老年受试者细胞中DNA修复合成相关基因（DNA聚合酶6、复制因子C、增殖细胞核抗原）mRNA表达量明显低于年轻受试者。此外，修复合成关键因子的催化亚基DNA聚合酶61的蛋白水平与mRNA水平相关。这些研究结果表明，衰老过程中紫外线后DNA修复能力的降低是由于修复合成因子表达减少导致NER后一步受损所致。
A reduction in the post-ultraviolet (UV) DNA repair capacity is associated with aging. To clarity the mechanism of this change, we examined the DNA repair capacity of skin fibroblasts from healthy donors of different ages by the two methods: host cell reactivation (HCR) assay and ELISA of cyclobutane pyrimidine dimers and pyrimidine-pyrimidone (6-4) photoproducts. In HCR assay, cells from elderly donors exhibited significant declines in the ability to restore transfected reporter DNA damaged by UV light. In contrast, the ability to remove DNA damage declined little with age in ELISA. These results imply that the age-sensitive step took place after the damage excision in nucleotide excision repair (NER). The mRNA expression of DNA repair synthesis-related genes (DNA polymerase 6, replication factor C, and proliferating cell nuclear antigen) were markedly decreased in the cells from multiple elderly subjects compared with those from young subjects. Further, the protein level of DNA polymerase 61, a catalytic subunit of the pivotal factor in repair synthesis, correlated with the mRNA level. These findings suggest that the reduced post-UV DNA repair capacity in aging results from an impairment in the latter step of NER by the decreased expression of factors in repair synthesis.