den Dulk Ben, van Eijk Patrick, de Ruijter Martina, Brandsma Jourica A, Brouwer Jaap
MGC Department of Molecular Genetics, Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands.
DNA Repair (Amst). 2008 Jun 1;7(6):858-68. doi: 10.1016/j.dnarep.2008.02.004. Epub 2008 Apr 1.
In the yeast Saccharomyces cerevisiae the Rad4-Rad23 complex is implicated in the initial damage recognition of the Nucleotide Excision Repair (NER) pathway. NER removes a variety of lesions via two subpathways: Transcription Coupled Repair (TCR) and Global Genome Repair (GGR). We previously showed that the new NER protein Rad33 is involved in both NER subpathways TCR and GGR. In the present study we show UV induced modification of Rad4 that is strongly increased in cells deleted for RAD33. Modification of Rad4 in rad33 cells does not require the incision reaction but is dependent on the TCR factor Rad26. The predicted structure of Rad33 shows resemblance to the Centrin homologue Cdc31. In human cells, Centrin2 binds to XPC and is involved in NER. We demonstrate that Rad4 binds Rad33 directly and via the same conserved amino acids required for the interaction of XPC with Centrin2. Disruption of the Rad4-Rad33 interaction is sufficient to enhance the modification of Rad4 and results in a repair defect similar to that of a rad33 mutant. The current study suggests that the role of Rad33 in the Rad4-Rad23 complex might have parallels with the role of Centrin2 in the XPC-HHR23B complex.
在酿酒酵母中，Rad4-Rad23复合物参与核苷酸切除修复（NER）途径的初始损伤识别。NER通过两个子途径去除多种损伤：转录偶联修复（TCR）和全基因组修复（GGR）。我们之前表明，新的NER蛋白Rad33参与NER的两个子途径TCR和GGR。在本研究中，我们发现紫外线诱导的Rad4修饰在缺失RAD33的细胞中显著增加。rad33细胞中Rad4的修饰不需要切口反应，但依赖于TCR因子Rad26。Rad33的预测结构与中心蛋白同源物Cdc31相似。在人类细胞中，中心蛋白2与XPC结合并参与NER。我们证明Rad4直接与Rad33结合，且通过与XPC和中心蛋白2相互作用所需的相同保守氨基酸结合。Rad4-Rad33相互作用的破坏足以增强Rad4的修饰，并导致与rad33突变体类似的修复缺陷。当前研究表明，Rad33在Rad4-Rad23复合物中的作用可能与中心蛋白2在XPC-HHR23B复合物中的作用相似。
