p53 protein activates the transcription of human proliferating cell nuclear antigen in response to 4-nitroquinoline N-oxide treatment.
4-nitroquinoline N-oxide (4-NQO) is a potent mutagen and carcinogen. To elucidate the cellular response to 4-NQO, we studied the transcriptional regulation of human proliferating cell nuclear antigen (hPCNA), an essential protein in DNA replication and repair, after 4-NQO treatment. We found that hPCNA promoter was dose-dependently transactivated by 4-NQO under the concentration of 2 microM via a previously reported p53-binding element located from -236 to -217 upstream of the transcription start site. Based on our western blot analysis, the phosphorylation of serine at the 15th residue (Ser15) of p53 was activated by 4-NQO, whereas the level of p53 in the cells did not change much. It was observed that Staurosporine, a Ser/Thr kinase inhibitor, blocked the Ser15 phosphorylation of p53 and the hPCNA promoter response to 4-NQO simultaneously, suggesting that Ser15 phosphorylated p53 was the 4-NQO-responsive hPCNA regulator. The [3H]-thymidine deoxyribose (TdR) incorporation assay and the comet assay showed that DNA repair was triggered when DNA replication was inhibited after the treatment of 4-NQO, and the hPCNA transactivation seemed to contribute to DNA repair. Taken together, our data indicate that after 4-NQO treatment hPCNA is transactivated by Ser15 phosphorylated p53, and participate in DNA repair.
Li
Yuanyuan
Y
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, 200031 Shanghai, PR China.
Wang
Lei
L
Li
Shihua
S
Guo
Tingqing
T
Guo
Xiuyang
X
Yan
Peijun
P
Chen
Ying
Y
Wang
Lingzhi
L
Lu
Changde
C
D015112:4-Nitroquinoline-1-oxide / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D004260:DNA Repair / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D002273:Carcinogens; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; D015112:4-Nitroquinoline-1-oxide; D017346:Protein Serine-Threonine Kinases