OBJECTIVETo study liver plasma membrane (PM) proteins affected by hepatitis B virus (HBV), and to study the molecular mechanism of HBV infection through plasma membrane proteome analysis of transgene mice livers.

METHODSPlasma membrane was purified using second antibody superparamagnetic beads that combine subcellular fractionation and immunoisolation strategies. Western blot was used to verify the purification of plasma membrane and the expression of HBV envelope protein. The proteins from plasma membrane were extracted, quantified and separated by two-dimensional electrophoresis. The gels were stained by silver nitrate or Coomassie Blue and analyzed by Imagemaster software. The different expressed proteins were identified by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF-TOF MS).

RESULTSThe plasma membrane of mice livers was enriched 3-fold and the contamination from mitochondria was reduced 2-fold in comparison with the density gradient centrifugation method. HBV envelope protein was found only in HBV transgene mice livers. More than 500 protein spots were separated in Coomassie Blue stained gels. Twenty-six proteins with two-fold differences were found through Imagemaster software analysis. Seven proteins were identified.

CONCLUSIONAn optimized plasma membrane purification method was developed; protein profile of liver plasma membrane changed in the transgene mice livers; some proteins related to HBV infection were found, and this work may be helpful in the research of the molecular mechanism of HBV infection.