Abstract
PrP
C, 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 PrP
C must be expressed in these cells. Accordingly, monoclonal antisera directed against two epitopes of hamster PrP
C 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 PrP
C 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.