Hepatitis B virus X protein interacts with β5 subunit of heterotrimeric guanine nucleotide binding protein

Abstract Background To isolate cellular proteins interacting with hepatitis B virus X protein (HBX), from HepG2 cells infected with hepatitis B virus (HBV). Results HBV particles were produced in culture medium of HepG2 cells transfected with the mammalian expression vector containing the linear HBV genome, as assessed by commercially available ELISA assay. A cDNA library was made from these cells exposed to HBV. From yeast two hybrid screening with HBX as bait, human guanine nucleotide binding protein β subunit 5L (GNβ5) was isolated from the cDNA library constructed in this study as a new HBX-interacting protein. The HBX-GNβ5 interaction was further supported by mammalian two hybrid assay. Conclusion The use of a cDNA library constructed from HBV-transfected HepG2 cells has resulted in the isolation of new cellular proteins interacting with HBX.