Mechanism of telomere shortening by oxidative stress
Mechanism of telomere shortening by oxidative stress
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DOI：
10.1196/annals.1297.047
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发表时间：
2004-01-01
期刊：
影响因子：
--
通讯作者：
Oikawa, S
中科院分区：
文献类型：
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作者：
Kawanishi, S;Oikawa, S
我们研究了导致衰老的氧化应激是否会加速人类培养细胞的端粒缩短。用UVA（365 nm光）照射的WI-38成纤维细胞的末端限制性片段（TRF）随着照射剂量的增加而减少。此外，UVA 照射剂量依赖性地增加 WI-38 成纤维细胞和 HL-60 细胞中 8-oxo-7,8-diHydro-2'deoxyguanosine (8-oxodG) 的形成。为了阐明端粒加速缩短的机制，我们使用含有端粒寡核苷酸 (TTAGGG) 的 P-32 5' 端标记 DNA 片段研究了在内源性光敏剂存在下 UVA 照射诱导的位点特异性 DNA 损伤(4)。核黄素的 UVA 照射诱导含有端粒序列的 DNA 片段中 8-oxodG 的形成，Fpg 蛋白处理导致端粒序列中 5'-GGG-3' 的中心鸟嘌呤发生链断裂。人 8-oxodG-DNA 糖基化酶在双链寡核苷酸中特别是在 8-oxodG 残基处引入链断裂。含有端粒序列[5'-CGC(TTAGGG)(7)CGC-3']的DNA片段中8-oxodG的形成量大约是含有非端粒序列[5'-CGC(TGTGAG)(7)CGC-3']的DNA片段中的5倍多。此外，H2O2 Plus Cu(II) 会造成 DNA 损伤，包括 8-oxodG 形成，特别是端粒序列中的 GGG 序列 (5'-TTAGGG-3')。结论氧化应激诱导的端粒序列GGG三联体上8-oxodG的形成可能参与了端粒缩短的加速过程。
We investigated whether oxidative stress, which contributes to aging, accelerates the telomere shortening in human cultured cells. The terminal restriction fragment (TRF) from WI-38 fibroblasts irradiated with UVA (365-nm light) decreased with increasing of the irradiation dose. Furthermore, UVA irradiation dose-dependently increased the formation of 8-oxo-7,8-dihydro-2'deoxyguanosine (8-oxodG) in both WI-38 fibroblasts and HL-60 cells. In order to clarify the mechanism of the acceleration of telomere shortening, we investigated site-specific DNA damage induced by UVA irradiation in the presence of endogenous photosensitizers using P-32 5'end-labeled DNA fragments containing telomeric oligonucleotide (TTAGGG)(4). UVA irradiation with riboflavin induced 8-oxodG formation in the DNA fragments containing telomeric sequence, and Fpg protein treatment led to chain cleavages at the central guanine of 5'-GGG-3' in telomere sequence. Human 8-oxodG-DNA glycosylase introduces a chain break in a double-stranded oligonucleotide specifically at an 8-oxodG residue. The amount of 8-oxodG formation in DNA fragment containing telomere sequence [5'-CGC(TTAGGG)(7)CGC-3'] was approximately five times more than that in the DNA fragment containing nontelomere sequence [5'-CGC(TGTGAG)(7)CGC-3']. Furthermore, H2O2 Plus Cu(II) caused DNA damage, including 8-oxodG formation, specifically at the GGG sequence in the telomere sequence (5'-TTAGGG-3'). It is concluded that the formation of 8-oxodG at the GGG triplet in telomere sequence induced by oxidative stress could participate in acceleration of telomere shortening.