The open reading frame of the porcine prion protein gene was inserted into an expression vector containing the mouse prion protein promoter, exon 1, intron 1, exon 2 and 3' untranslated region. Expression of the porcine prion protein in brains of homozygous transgenic mice, determined by western blot analysis, was fourfold that observed in pig brain homogenate. (J:132565)