Screening of hepatitis B surface antigen-interacted liver cell proteins by yeast two-hybrid system.

To screen the liver cell proteins which interacts with middle hepatitis B surface protein(MHBs protein),the sequences encoding MHBs was amplified by means of PCR and the start codon of S region ATG was mutated to ACG to generate the target gene MHBs-mut,then the MHBs-mut was cloned into the bait vector pGBKT7.After exclusion of self-activation capacities of MHBs-mut protein,a two-hybrid library screening was performed using a pre-transformed human liver cDNA library to screen the liver cell proteins interacting with MHBs-mut.Analysis and verification of putative positive clones were also done to further confirm the interactions in AH109 yeast cells.Results indicated that liver cell protein of Homo sapiens COP9 constitutive photomorphogenic homolog subunit 5(COPS5) was found to be able to interact with MHBs-mut in AH109.