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THE HEPATITIS-B VIRUS-ENCODED TRANSCRIPTIONAL TRANSACTIVATOR HBX APPEARS TO BE A NOVEL PROTEIN SERINE THREONINE KINASE CELL Wu, J. Y., Zhou, Z. Y., Judd, A., Cartwright, C. A., Robinson, W. S. 1990; 63 (4): 687-695

Abstract

To study the functional mechanism of the hepatitis B virus (HBV) X (hbx) gene product, we have expressed the hbx protein in E. coli and purified it by HPLC. The purified hbx protein was shown to be active in transactivating transcription directed by the LTR sequence of HIV-1. The hbx protein was found to have an intrinsic serine/threonine protein kinase activity. The hbx protein was detected in hepatitis B virions, and tryptic phosphopeptide maps of the hbx protein phosphorylated in the virion and of the in vitro phosphorylated bacterially expressed hbx protein were similar. Inactivation of the hbx protein by heat, protein-denaturing agents, or an ATP affinity analog, p-fluorosulfonylbenzoyl 5'-adenosine, resulted in loss of both protein kinase activity and trans-activation activity. These results suggest that the HBV-encoded trans-activator hbx is a novel protein kinase.

View details for Web of Science ID A1990EJ59000005

View details for PubMedID 2225072