Svetlova M P, Solovjeva L V, Pleskach N A, Tomilin N V
Institute of Cytology, The Russian Academy of Sciences, Tikchoretskii Av. 4, St. Petersburg, 194064, Russian Federation.
Biochem Biophys Res Commun. 1999 Apr 13;257(2):378-83. doi: 10.1006/bbrc.1999.0485.
Nucleotide excision repair (NER) is the principle pathway by which the human cells eliminate UV-induced lesions from their genomic DNA. The process can be visualized through the labelling of the nucleotides that are incoporated into repair patches, following the excision of the damaged stretch of DNA. In this study we have visualized sites of DNA repair synthesis (DRS) in human interphase and metaphase chromosomes after very short times (2.5-30 min) of postirradiation labelling in vivo with 5-iododeoxyuridine. A limited number (<50 per nucleus) of discrete nuclear DRS sites were seen in cells fixed immediately after labelling and the sites are also detectable in interphase and metaphase chromosomes visualized 48h after irradiation (3 J/m2). These observations strongly support the view that within a given short time window distinct chromosome domains are under extensive repair while in many other domains NER is slow. They argue against the general distributative NER process but are consistent with a processive scanning of damaged domains.
核苷酸切除修复（NER）是人类细胞从基因组DNA中消除紫外线诱导损伤的主要途径。在切除受损的DNA片段后，通过标记掺入修复补丁的核苷酸，可以观察到这一过程。在本研究中，我们利用5-碘脱氧尿苷在体内进行辐照后极短时间（2.5-30分钟）标记，观察了人间期和中期染色体上DNA修复合成（DRS）的位点。标记后立即固定的细胞中可见数量有限（每个细胞核<50个）的离散核DRS位点，并且在辐照（3 J/m2）48小时后可视化的间期和中期染色体中也可检测到这些位点。这些观察结果有力地支持了这样一种观点，即在给定的短时间窗口内，不同的染色体区域正在进行广泛的修复，而在许多其他区域，NER则很缓慢。它们反对普遍的分布式NER过程，但与受损区域的连续扫描过程一致。
