AIM:To establish the transgenic mouse line harbouringcomplete hepatitis B virus(HBV)genome with mutant sgene(adr subtype).METHODS:Transgenic mice were generated by microinjectingHBV genome into fertilized eggs.Integration,expression,replication of HBV gene and histological changes intransgenic mice were estimated by genomic DNA PCR,serum DNA PCR,Southern blot,ELISA,HE staining,immunohistochemistry and transmission electronmicroscopy.Transgenic mice with HBsAg positive in serumwere bred and analyzed.RESULTS:A total of 288 eggs survived from microinjectionswere transplanted into the oviducts of 13 pseudopregnantmice and 49 pups were produced.Twenty-six mice wereidentified to have the integrated HBV gene.Serum HBsAgand HBeAg were detected in 2 of 43 mice.HBsAg andHBcAg in cytoplasm or nuclei of hepatocytes were detectedin 10 mice.Founders with HBsAg in serum were namedlineages G145R-15 and G145R-18.Of the 16 F1 offspringsgenerated by G145R-15 founder,12 were positive for HBVgenome with PCR,10 were positive for HBsAg and HBcAgwith immunohistochemistry and 7 were positive for HBsAgand HBeAg with ELISA.Only 1 of 8 F1 offsprings generatedby G145R-18 founder was survived and it was detectedpositive for HBV genome,HBsAg,HBcAg and HBeAg.Bothof the two lineages had some pathological characteristicsof mild chronic hepatitis B in the liver,such as swelling ofhepatocytes and focal hepatocellular necrosis and parenchymallymphomononuclear cell infiltrate.CONCLUSION:Transgenic mice harbouring HBV withmutant s gene can be generated.The HBV genes areintegrated in the transgenic mice genome and can beexpressed,replicated,packaged and excreted.HBV DNAcan be stably transmitted in the transgenic mice.Ge JH,Zhang LZ,Li JX,Liu H,Liu HM,He J,Yao YC,Yang YJ, Yu HY,Hu YP.Replication and gene expression of mutanthepatitis B virus in a transgenic mouse containing the completeviral genome with mutant s gene.World J Gastroenterol2004;10(21):3141-3145http://www.wjgnet.com/1007-9327/10/3141.asp AIM: To establish the transgenic mouse line harboring complete hepatitis B virus (HBV) genome with mutant sgene (adr subtype). METHODS: Transgenic mice were generated by microinjecting HBV genome into fertilized eggs. Expression, expression, replication of HBV gene and histological changes intragenic mice were estimated by genomic DNA PCR, serum DNA PCR, Southern blot, ELISA, HE staining, immunohistochemistry and transmission electron microscopy. Transgenic mice with HBsAg positive in serumwere bred and analyzed.RESULTS: A total of 288 eggs survived from microinjectionwere transplanted into the oviducts of 13 pseudopregnantmice and 49 pups were produced. Twenty-six mice were identified to have the integrated HBV gene. Serum HBsAg and HBeAg were detected in 2 of 43 mice. HBsAg and HBcAg in cytoplasm or nuclei of hepatocytes were detected in 10 mice. Founders with HBsAg in serum were named lineages G145R-15 and G145R-18.Of the 16 F1 offspringsgenerated by G145R-15 founder, 12 were positive for HBV genome with PC R, 10 were positive for HBsAg and HBcAg with immunohistochemistry and 7 were positive for HBsAg and HBeAg with ELISA. Only 1 of 8 F1 offsprings generatedby G145R-18 founder was survived and it was found positive for HBV genome, HBsAg, HBcAg and HBeAg.Bothof the two lineages had some pathological characteristics of mild chronic hepatitis B in the liver, such as swelling of hepatocytes and focal hepatocellular necrosis and parenchymallymphomononuclear cell infiltrate. CONCLUSION: Transgenic mice harboring HBV with mutants gene can be generated. The HBV genes areintegrated in the transgenic mice genome and can replicated, packaged and excreted. HBV DNAcan be stably transmitted in the transgenic mice. Ge JH, Zhang LZ, Li JX, Liu H, Liu HM, He J, Yao YC, Yang YJ, Yu HY, Hu YP. Replication and gene expression of mutant hepatitis B virus in a transgenic mouse containing the complete viral genome with mutant s gene. World J Gastroenterol 2004; 10 (21): 3141-3145 http: //www.wjgnet.com/1007-9327/10/3141.asp