HBV X protein targets HIV Tat-binding protein 1.
The HBV X protein (HBx) is implicated in infection and development of hepatocellular carcinoma. HBx has a pleiotropic effect on cells, suggesting multiple targets in the virus-host cell interaction. We employed the cytoplasmic-based two-hybrid screen and identified the HIV Tat-binding protein 1 (Tbp1) as a novel HBx interacting protein. Tbp1 interacts in vivo with HBx both in yeast and in animal cells. This interaction maps to the functionally important ATP-binding motif of Tbp1. Furthermore, HBx and Tbp1 interaction is functionally significant and regulates HBV transcription. Tbp1 homologues, such as Sug1, are known members of the proteasome 19S regulatory cap particle and have also been implicated in transcription coactivation. Remarkably, Tbp1 and Sug1 interact with multiple viral effector proteins including HIV Tat, SV40 large T antigen, and adenovirus E1A, establishing these proteins as important targets of the viral oncogenes.
Barak
O
O
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Aronheim
A
A
Shaul
Y
Y
D000074183:ATPases Associated with Diverse Cellular Activities; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D015723:Gene Library; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D011233:Precipitin Tests / Q000379:methods; D046988:Proteasome Endopeptidase Complex; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020664:Son of Sevenless Proteins / Q000235:genetics / Q000378:metabolism; D013347:Subcellular Fractions; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D020798:Two-Hybrid System Techniques; D054334:Viral Regulatory and Accessory Proteins; D015003:Yeasts
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D020664:Son of Sevenless Proteins; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D046988:Proteasome Endopeptidase Complex; D000074183:ATPases Associated with Diverse Cellular Activities; C064757:PSMC3 protein, human