Al-Moghrabi N M, Al-Sharif I S, Aboussekhra A
King Faisal Specialist Hospital and Research Center, Department of Biological and Medical Research, MBC-03, PO Box 3354, Riyadh 11211, Kingdom of Saudi Arabia.
Nucleic Acids Res. 2001 May 15;29(10):2020-5. doi: 10.1093/nar/29.10.2020.
Cells respond to DNA damage by activating both cellular growth arrest and DNA repair processes. In Saccharomyces cerevesiae the RAD9 gene controls DNA damage-mediated cell cycle arrest that is known to allow efficient repair. To ascertain whether RAD9 plays a role in DNA repair per se, the removal of UV-induced photolesions was assessed in synchronized isogenic normal and rad9 cells using the high resolution primer extension technique. The results show that RAD9 is indeed involved in the removal of photolesions from both the transcribed and the non-transcribed strands of the reporter GAL10 gene, in G(1)- as well as G(2)/M-arrested cells. Interestingly, these data also reveal that in both normal and rad9 mutant, the repair strand bias towards the transcribed stand is more pronounced in G(2)/M- than in G(1)-arrested cells. These data indicate that RAD9 coordinate the cellular response to DNA damage by activating both cell cycle checkpoint and excision repair.
细胞通过激活细胞生长停滞和DNA修复过程来应对DNA损伤。在酿酒酵母中，RAD9基因控制DNA损伤介导的细胞周期停滞，已知这能实现高效修复。为确定RAD9本身是否在DNA修复中发挥作用，使用高分辨率引物延伸技术在同步化的同基因正常细胞和rad9细胞中评估了紫外线诱导的光损伤的去除情况。结果表明，在G(1)期以及G(2)/M期停滞的细胞中，RAD9确实参与了从报告基因GAL10基因的转录链和非转录链上去除光损伤。有趣的是，这些数据还显示，在正常细胞和rad9突变体中，与G(1)期停滞的细胞相比，G(2)/M期停滞的细胞中修复链对转录链的偏向更为明显。这些数据表明，RAD9通过激活细胞周期检查点和切除修复来协调细胞对DNA损伤的反应。
