Establishment and detection of HBV transgenic mice with YMDD mutation

Objective To establish the hepatitis B virus(HBV) transgenic mice with YMDD mutation,and provide an animal model for research of HBV prevention and therapeutic approach.Methods 1.3 copies HBV genome containing YMDD mutation associated with lamivudine resistance was injected into the zygote of FVB/N female mice by microinjection.Integration and passage of exogenous gene in transgenic mice was confirmed by PCR.The expression of HBsAg in liver and kidney tissues in transgenic mice was identified by ELISA and immunohistochemistry.Results A total of 3401 zygotes were injected and 269 F0 pups were born.PCR analysis indicated that 33 out of 269 pups were positive,and the integrating rate of exogenous gene was 12.3% in F0.Fluorescent quantitative PCR showed that HBV DNA was weakly positive in serum samples in 9 transgenic mice,less than 103copies/ml.The expression of HBsAg in transgenic mice was observed in liver and kidney tissues by immunohistochemistry,and it was higher in kidney than in liver.The target gene was detected by PCR in 27.6% of 47 F1 offsprings.The expression of HBsAg could be observed in liver and kidney tissues in F1,which was similar to that in F0.Conclusion 1.3 copies HBV transgenic mice model containing YMDD mutation associated with lamivudine resistance is successfully produced by microinjection,and HBsAg expression can be transmitted through germline cells.