CHARACTERIZATION OF TRANSGENIC MICE LINEAGES .2. TRANSGENIC MICE EXPRESSING HBSAG PARTICLES AND SHOWING FEMALE STERILITY

The tissue specificity of the expression of the hepatitis B surface an tigen (HBsAg) in transgenic mice was studied. Northern blot hybridizat ion and electron microscopy of various tissues revealed the higher HBs Ag transcription levels confined to the liver and kidney, and to a les ser extent to the spleen and intestines. In electron microscopic studi es we found HBsAg particles in the serum of transgenic animals to be p ositive by ELISA to HBsAg. The expression of the transgene was localiz ed in situ in the ovary, liver, kidney, and spleen of transgenic mice, employing a polyclonal antiserum directed against the HBsAg and conju gated with protein A-gold. Surprisingly, F1 transgenic females from th e CB-104 line, expressing HBsAg in the serum, showed impaired fertilit y, although the ovarian function was not diminished. Normal off-spring were obtained after cross embryo transfer between transgenic (Tg) fem ales to non-transgenic (Ntg) recipients or from Ntg embryos transferre d to Tg recipients. We speculate that this phenomenon could be related to a disruption on a gene(s) somehow involved in the reproductive per formance of the transgenic females.