Expression of prion protein (PrP) gene in rat tissues and cell lineswas investigated by reverse transcriptase polymerase chain reaction (RNA-peR) and Northern blot analyses. PrP cDNA clones were generated usingRNA-PCR from RNA preparation of neuronal cell line (HVI6-3), whichwere immortalized from rat embryonic hippocampal cells. These clonescontained 5 upstream region and an in-frame ATG codon which had notbeen reported previously in rat and were used as hydridization probes.RNA-PCR analyses showed that PrP mRNA was present in rat embryonichippocampal neuronal cell lines (HV3-3 and HVI6-3) and a rat glioma cellline’ (C6) as well as several different tissues from rat. In Northern blotanalysis, the PrP cDNA probe hydridized to a single approximate 2.8 kbmRNA band under stringent conditions, indicating that PrP gene wasexpressed in these neuronal cell lines (HV3-3 and HVI6-3) as well as in ratbrain. In this conditions, Northern blot analysis did not show PrP mRNAin C6 cell line, spleen, and liver from rat. The present results indicated thatPrP gene was expressed in these neuronal cell lines (HV3-3 and HVI6-3)as well as in rat brain.