Fig. 4

HBx attenuates the suppression of HBP1 on AFP through inhibiting binding of HBP1 to the AFP promoter. a HBx rescues the suppression of HBP1 on AFP protein. HepG2 cells were co-transfected HBP1 with or without HBx expression plasmid. The protein levels of HBP1, AFP and HBx were measured by Western blotting. b HBx rescues the suppression of HBP1 on AFP mRNA. The mRNA level of AFP was measured by Realtime-PCR in HepG2 cells transfected with HBP1 with or without HBx expression plasmid. c HBx rescues the suppression of HBP1 on AFP promoter. Two hundred-ninety three T cells were co-transfected with AFP promoter and HBP1 with or without HBx expression plasmid. Luciferase activity was determined after transfection. d HBx inhibits the interaction between HBP1 and AFP promoter. Two hundred-ninety three T cells were transfected with HA-HBP1 with or without HBx expression plasmid. The region from position − 1600 to position − 1448 contains the HBP1 affinity site and was analyzed by specific PCR. e HBP1 interacts with HBx. Two hundred-ninety three T cells were co-transfected with HA-HBP1 and FLAG-HBx. IP assay was carried out by using anti-FLAG/HA antibody and followed by Western blotting with anti-HA/FLAG antibody. The same samples were immunoblotted against FLAG/HA to determine immunoprecipitation efficiency. Error bars represent S.D. *, p < 0.05, **, p < 0.01