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1: Nucleic Acids Res. 1996 Dec 1;24(23):4741-50.Click here to read Click here to read Links

XAP2, a novel hepatitis B virus X-associated protein that inhibits X transactivation.

Kuzhandaivelu N, Cong YS, Inouye C, Yang WM, Seto E.

Moffitt Cancer Center and Research Institute, Department of Medical Microbiology and Immunology, University of South Florida, Tampa 33612, USA.

The hepatitis B virus X protein is a promiscuous transcriptional transactivator. Transactivation by the X protein is most likely mediated through binding to different cellular factors. Using the yeast two-hybrid method, we have isolated a clone that encodes a novel X-associated cellular protein: XAP2. X and XAP2 interactions also occur in vitro. Antiserum raised against XAP2 recognizes a cytoplasmic protein with an apparent molecular mass of 36 kDa. The interaction between X and XAP2 requires a small region on X containing amino acids 13-26. From Northern blot analyses, XAP2 is ubiquitously expressed in both liver-derived and non-liver-derived cell lines as well as in normal non-liver tissues. In contrast, XAP2 is expressed in very low level in the normal human liver. In transfection assays, overexpression of XAP2 abolishes transactivation by the X protein. Based on these results, we suggest that XAP2 is an important cellular negative regulator of the X protein, and that X-XAP2 interaction may play a role in HBV pathology.

PMID: 8972861 [PubMed - indexed for MEDLINE]

PMCID: PMC146319