We then isolated the moPrP.XhoI intron by amplification with primers that added an external BamHI site to the 5′ end of exon 1 and ran through the Asp718 site of exon 2 (forward: GCC GGA TCC GAT CAG CAG ACC GAT TCT GG; reverse: GCC GGT ACC ACT AGG AAG GCA GAA TGC).