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 precursor to abnormal PrP isoforms which accumulate in diseases such as scrapie in sheep, and Creutzfeldt-Jakob disease in humans. Since prions can replicate in photoreceptors we surmised that PrPC must be expressed in these cells. Accordingly, monoclonal antisera directed against two 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, coinciding with the earliest site of pathologic changes in scrapie-infected hamsters. These data define PrPC expression in an experimentally-accessible population of neurons and suggest that the retina may comprise a useful system for studying the biology of wild-type and mutant prion proteins. (C) 1997 Elsevier Science Ireland Ltd.