[Genetic transformation of somatic cells. XV. Production of transgenic mice containing the gene for the envelope protein of the human hepatitis B virus].

Transgenic mice containing in somatic (liver) cells a gene encoding hepatitis virus B surface antigen (HBsAg) were obtained and analysed. About 10(4)-10(5) copies of circular plasmid pSH21 with HBsAg gene under the control of the SV40 early promoter were microinjected into the cytoplasm (pronucleus region) of mouse zygotes. 10 of the 24 animals isolated after this treatment contained 1 to 5 copies of the HBsAg gene per genome of hepatocytes (7 males and 3 females). The Southern analysis of DNA from some of transgenic animals showed rearrangements of the HBsAg gene in most of them. In the liver of one female transcripts were found hybridizing with the probe on the HBsAg gene; progenies of this mouse expressed no HBsAg gene. Possible reasons for the high frequency HBsAg gene rearrangements in transgenic mice are discussed.