SYRIAN-HAMSTER PRION PROTEIN (PRPC) IS EXPRESSED IN PHOTORECEPTOR CELLS OF THE ADULT RETINA

PrPC, the cellular isoform of the prion protein (PrP) serves as a prec ursor to abnormal PrP isoforms which accumulate in diseases such as sc rapie in sheep, and Creutzfeldt-Jakob disease in humans. Since prions can replicate in photoreceptors we surmised that PrPC must be expresse d in these cells. Accordingly, monoclonal antisera directed against tw o epitopes of hamster PrPC produced retinal immunostaining in hamsters , and in mice bearing a hamster PrP transgene. Immunostaining was most prominent in the inner and outer segments of rod photoreceptors, coin ciding with the earliest site of pathologic changes in scrapie-infecte d hamsters. These data define PrPC expression in an experimentally-acc essible population of neurons and suggest that the retina may comprise a useful system for studying the biology of wild-type and mutant prio n proteins. (C) 1997 Elsevier Science Ireland Ltd.