Upregulation of Hsp90α expression by HBx. (A) HepG2 cells were transiently transfected with the indicated amount (1 μg, 2 μg, 3 μg) of pcDNA3-X and Western blotting of HSP90α was performed. (B) Total RNA purified from the HBxtransfected HepG2 cells was subjected to RT-PCR for measuring HSP90α transcripts. (C) Increasing amount (1 μg, 2 μg, 3 μg) of pcDNA3-X was cotransfected with 2 μg of HSP90α promoter-luciferase reporter constructs (Hsp90α-Luc1430), and 2 μg of β-galactosidase reporter plasmid into HepG2 cells and luciferase assay was performed. Luciferase activity was normalized with the β-alactosidase activity in cell lysate. Error bars indicate standard deviations (SD) obtained from three different experiments prepared in triplicate.