This transgene encodes a wild-type mouse prion protein. Expression studies demonstrated that this line expresses Prnp transcripts in the brain 6- to 7-fold compared to wild-type. Expression patterns were similar to those of wild-type mice with the notable exception that transcript was not detected in Purkinje cells. This transgenic construct, referred to as 'half genomic,' was designed to omit a large intron in order to facilitate subsequent mutagenesis studies.