We describe the expression of SAG-1 cDNA in B6C3F1 mice by microinjecting a
3.3 kbp DNA fragment, consisting of the cytomegalovirus enhancer-chicken b
eta-actin hybrid promoter and SAG-1 into the pronucleus of a fertilized egg
at the one-cell stage. Offspring derived from this microinjection were ana
lyzed for the integration and functional expression of the SAG-1 transgene.
Steady-state expressions of both the mRNA for SAG-1 and SAG-1 protein prod
uct were detected in the brain, thymus, spleen and liver. Approximately 50%
of F1 and F2 progeny inherited the SAG-1 transgene from SAG-1 transgenic m
ice in Mendelian fashion. These results indicated that SAG-1 transgenic lin
es were established. Transgenic mice harboring the SAG-1 gene will contribu
te a critical tool of defining the molecular mechanisms of SAG-1 in pathoge
nesis and host immune response.