[Transcriptional inhibitory effect of hepatitis B virus X protein on the expression of p53 tumor suppression gene].
BACKGROUND
To investigate the transcriptional inhibitory role of hepatitis B virus X protein on the expression of p53 tumor suppression gene.


METHODS
The promoter sequence of the p53 tumor suppression gene was identified and amplified by bioinformatics and polymerase chain reaction (PCR). The recombinant reporter gene expression vector pCAT3-p53p was constructed and transfected into the hepatoblastoma cell line HepG2 and cotransfected with pcDNA3.1 (-)-X by Fugene 6 transfection reagents. The chloramphenicol acetyl transferase (CAT) activity was detected by enzyme-linked immunosorbent assay (ELISA). The expression of p53 mRNA was further detected by RT-PCR with or without HBV X protein.


RESULTS
The reporter vector pCAT3-p53p has been successfully constructed and identified and the p53 promoter could cis-activate the transcription of the CAT gene. The relative expression level of CAT gene in HepG2 cells cotransfected with pCAT3-p53p and pcDNA3.1 (-)-X was lower than the control, and the inhibitory rate was approximately 78%, which indicate that HBV X protein could transcriptionally inhibit the activity of p53 promoter. After transfected with pcDNA3.1 (-)-X, the expression of p53 mRNA was lower than the control.


CONCLUSIONS
HBV X protein could transcriptionally inhibit the expression of p53 tumor suppression gene, which might be a possible molecular mechanism responsible for the development of HBV-associated hepatocellular carcinoma.
Li
Jin
J
Viral Hepatitis Research Center, Institute of Infectious Diseases, The 302 Hospital of The People's Liberation Army, Beijing 100039, China.
Liu
Yan
Y
Dai
Jiu-zeng
JZ
Xu
Dong-ping
DP
Zhang
Ling-xia
LX
D001483:Base Sequence; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic; D014162:Transfection / Q000379:methods; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D054334:Viral Regulatory and Accessory Proteins
D012333:RNA, Messenger; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein