Nucleotide excision repair from site-specifically platinum-modified nucleosomes
Nucleotide excision repair from site-specifically platinum-modified nucleosomes
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DOI：
10.1021/bi034264k
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发表时间：
2003-06-10
期刊：
影响因子：
2.9
通讯作者：
Lippard, SJ
中科院分区：
文献类型：
--
作者：
Wang, D;Hara, R;Lippard, SJ
核苷酸切除修复是对抗抗癌药物顺铂和其他铂类化疗药物毒性作用的主要细胞防御机制。在这项研究中，单核小体制备含有位点特异性顺式二氨铂（II）-DNA链内d（GpG）或d（GpTpG）交联。研究了组蛋白核心调节这些定义的铂加合物切除的能力，作为探索染色质中铂-DNA加合物的细胞反应的模型。比较哺乳动物细胞提取物的自由和核小体DNA含有相同的铂-DNA加合物的修复程度表明，核小体显着抑制核苷酸切除修复。使用GTG-Pt DNA底物，核小体抑制切除至用游离DNA观察到的水平的约10%，而使用效率较低的GG-Pt DNA底物，核小体抑制切除至用游离DNA观察到的水平的约30%。通过比较含有相同链内d（GpTpG）交联的天然和重组核小体，研究了组蛋白翻译后修饰对从核小体切除铂损伤的影响。天然核小体DNA的切除率比重组材料高2倍。这一结果表明，组蛋白的翻译后修饰可以调节受损染色质的核苷酸切除修复。在这项研究中建立的体外系统将有助于调查铂-DNA损伤的DNA修复过程，并有助于阐明特定的翻译后修饰的作用，在NER的铂-DNA加合物在生理相关的核小体水平。
Nucleotide excision repair is a major cellular defense mechanism against the toxic effects of the anticancer drug cisplatin and other platinum-based chemotherapeutic agents. In this study, mononucleosomes were prepared containing either a site-specific cis-diammineplatinum(II) -DNA intrastrand d(GpG) or a d(GpTpG) cross-link. The ability of the histone core to modulate the excision of these defined platinum adducts was investigated as a model for exploring the cellular response to platinum-DNA adducts in chromatin. Comparison of the extent of repair by mammalian cell extracts of free and nucleosomal DNA containing the same platinum-DNA adduct reveals that the nucleosome significantly inhibits nucleotide excision repair. With the GTG-Pt DNA substrate, the nucleosome inhibits excision to about 10% of the level observed with free DNA, whereas with the less efficient GG-Pt DNA substrate the nucleosome inhibited excision to about 30% of the level observed with free DNA. The effects of posttranslational modification of histones on excision of platinum damage from nucleosomes were investigated by comparing native and recombinant nucleosomes containing the same intrastrand d(GpTpG) cross-link. Excision from native nucleosomal DNA is similar to2-fold higher than the level observed with recombinant material. This result reveals that post-translational modification of histones can modulate nucleotide excision repair from damaged chromatin. The in vitro system established in this study will facilitate the investigation of platinum-DNA damage by DNA repair processes and help elucidate the role of specific post-translational modification in NER of platinum-DNA adducts at the physiologically relevant nucleosome level.