HHR23A, a human homolog of Saccharomyces cerevisiae Rad23, regulates xeroderma pigmentosum C protein and is required for nucleotide excision repair.
HHR23A and hHR23B are the human homologs of Saccharomyces cerevisiae Rad23. hHR23B is associated with the nucleotide excision repair (NER) factor xeroderma pigmentosum C (XPC) protein and is required for global genome repair. The function of hHR23A is not yet clear. In this study, the potential function of the hHR23A protein was investigated using RNA interference techniques. The hHR23A knock-down (KD) construct diminished the RNA level of hHR23A protein by approximately 60%, and it did not interfere with expression of the hHR23B gene. Based on Southwestern immunoblot and host-cell reactivation assays, hHR23A(KD) cells were found to be deficient in DNA repair activity against the DNA damage caused by UVC irradiation. In these hHR23A(KD) cells, the XPC gene was not normally induced by UVC irradiation, indicating that the hHR23A protein is involved in NER through regulation of the DNA damage recognition protein XPC. Co-immunoprecipitation experiments revealed that hHR23A was associated with a small portion of hHR23B and the majority of p53 protein, indicating that hHR23A regulates the function of XPC by its association with the NER activator p53.
Hsieh
Hui-Chuan
HC
Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.
Hsieh
Yi-Hsuan
YH
Huang
Yu-Hsin
YH
Shen
Fan-Ching
FC
Tsai
Han-Ni
HN
Tsai
Jui-He
JH
Lai
Yu-Ting
YT
Wang
Yu-Ting
YT
Chuang
Woei-Jer
WJ
Huang
Wenya
W
D045744:Cell Line, Tumor; D002470:Cell Survival; D004247:DNA / Q000235:genetics*; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D011485:Protein Binding; D034622:RNA Interference; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D004268:DNA-Binding Proteins; C490846:RAD23 protein, S cerevisiae; C513287:RAD23B protein, human; D029701:Saccharomyces cerevisiae Proteins; D016159:Tumor Suppressor Protein p53; C086985:RAD23A protein, human; C086984:XPC protein, human; D004247:DNA; D045643:DNA Repair Enzymes