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.
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, 200031 Shanghai, PR China.
Yuanyuan
Y
Li
Lei
L
Wang
Shihua
S
Li
Tingqing
T
Guo
Xiuyang
X
Guo
Peijun
P
Yan
Ying
Y
Chen
Lingzhi
L
Wang
Changde
C
Lu
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