High level expression of human alpha-fetoprotein in transgenic mice.

Transgenic mice were produced by the microinjection of the cDNA of human alpha-fetoprotein (AFP) under control of the enhancer/promoter of the human beta-actin gene. Among the 4 mouse lines where the transgene were stable transmitted to the progeny, 3 produced human AFP. The expression was not developmental stage-specific nor tissue-specific as predicted from the properties of enhancer/promoter. The serum human AFP levels of adult mice were 30-600-fold higher than those of mouse AFP. These mice could be useful for the studies of possible biological functions of AFP during development as well as in malignancies.