Electrophoretic analysis of nucleic acids isolated from scrapie-infected hamster brain.

The purpose of this study was to investigate previous reports of a scrapie-specific 1.2 kb single-stranded DNA observed in alkaline agarose electrophoresis gels. Protocols were developed to be as consistent as possible with those used previously. Partial subcellular fractionation was applied to the brains of hamsters clinically affected by the 263K strain of scrapie. Nucleic acids were then isolated, and compared electrophoretically to nucleic acids isolated from equivalent fractions, made from the brains of hamsters inoculated with normal brain. Several modifications to the protocols were suggested. Results obtained by using these modifications were compared to results obtained using the original protocols. Scrapie-specific DNA was not observed in a total of eleven consecutive experiments. Thus, these results do not support the hypothesis that the agents of transmissible spongiform encephalopathy contain a single-stranded 1.2 kb DNA species as previously described.