[HBxAg enhanced p53 protein accumulation in hepatoma cells].
OBJECTIVE
In order to determine the interaction between HBxAg and p53 protein and its role in hepatocarcinogenesis.


METHODS
Cotransfection was performed using reporter gene, chloramphenical acetyltransferase (CAT), p53 and HBVx gene, and dexamethasone inducible HBx plasmid pMAMHBx was constructed for the experiment. Human hepatoma cell line Hep3B was used as the target cell. The activity of HBxAg and p53 was detected by CAT assay and immunohistochemical staining after transient transfection.


RESULTS
HBxAg could increase the accumulation of p53 protein in cells and enhance CAT expression. Immunohistochemical staining showed that p53 protein bound to HBxAg in the cytoplasm and formed a complex causing a partial block of the process of p53 during passing through the nuclear membrane from the cytoplasm.


CONCLUSIONS
Data strongly suggested that HBxAg is capable of binding p53 and forms a protein-protein complex which might reduce or inactivate p53's antiproliferative activity and plays an important role in the pathogenesis of HBV-associated hepatocellular carcinoma.
Zhu
M
M
Department of Pathology, Second Military Medical University, Shanghai 200433.
Dai
Y
Y
Zhan
R
R
D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008856:Microscopy, Fluorescence; D010957:Plasmids / Q000235:genetics; D011485:Protein Binding; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins
D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein