Suter B, Wellinger R E, Thoma F
Institut für Zellbiologie, ETH-Zürich, Hönggerberg, CH-8093 Zürich, Switzerland.
Nucleic Acids Res. 2000 May 15;28(10):2060-8. doi: 10.1093/nar/28.10.2060.
DNA damage formation and repair are tightly linked to protein-DNA interactions in chromatin. We have used minichromosomes in yeast as chromatin substrates in vivo to investigate how nucleotide excision repair (NER) and repair by DNA-photolyase (photoreactivation) remove pyrimidine dimers from an origin of replication ( ARS1 ). The ARS1 region is nuclease sensitive and flanked by nucleosomes on both sides. Photoreactivation was generally faster than NER at all sites. Site-specific heterogeneity of repair was observed for both pathways. This heterogeneity was different for NER and photoreactivation and it was altered in a minichromosome where ARS1 was transcribed. The results indicate distinct inter-actions of the repair systems with protein complexes bound in the ARS region (ORC, Abf1) and a predominant role of photolyase in CPD repair of an origin of replication.
DNA损伤的形成与修复与染色质中蛋白质-DNA的相互作用紧密相关。我们利用酵母中的微型染色体作为体内染色质底物,来研究核苷酸切除修复(NER)和DNA光解酶修复(光复活)如何从复制起点(ARS1)去除嘧啶二聚体。ARS1区域对核酸酶敏感,两侧均有核小体。在所有位点,光复活通常比NER更快。两种修复途径均观察到位点特异性的修复异质性。NER和光复活的这种异质性不同,并且在转录ARS1的微型染色体中发生了改变。结果表明修复系统与结合在ARS区域的蛋白质复合物(ORC、Abf1)存在不同的相互作用,并且光解酶在复制起点的CPD修复中起主要作用。