Preliminary study on the production of transgenic mice harboring hepatitis B virus X gene

AIM:To establish transgenic mice lineage harboring hepatitis B virus X gene and to provide an efficient animal model for studying the exact role of the HBx gene in the process of hepatocarcinogenesis.METHODS:The HBx transgenic mice were produced by microinjecting the construct with X gene of HBV (subtype adr) DNA fragment into fertilzed eggs derived from inbred C57BL/6 strain; transgenic mice were identified by using Nested PCR; expression and phenotype of HBx gene were analyzed in liver from transgenic mic at the age of 8 weeks by RT-PCR, pathologic examination and periodic acid-schiff staining (PAS), respectively.RESULTS:Five hundred and fourteen fertilized eggs of C57 BL/6 mice were microinjected with recombinant retroviral DNA fragment, and 368 survival eggs injected were transferred to the oviducts of 18 pseudopregnant recipient mice, 8 of them became pregnant and gave birth to 20 F1 offspring. Of 20 offsprings, four males and two females carried the hybrid gene (HBx gene). Four male mice were determined as founder, named X 1, X 5, X 9 and X 15. These founders were back crossed to set up F1 generations with other ibred C57BL/6 mice or transgenic littermates, respectively.Transmission of HBx gene in F1 offspring of X 1, X 5 and X 9 except in X 15 followed Mendelian rules. The expression of HBx mRNA was detected in liver of F1 offspring from the founder mice (X 1 and X 9), which showed vacuolation lesion and glycogen positive foci.CONCLUSION:Transgenic mice harboring HBx gene were preliminarily established.