Evidence that single-stranded DNA wrapped around the tubulofilamentous particles termed "nemaviruses" is the genome of the scrapie agent.

ABSTRACT

Homogenized brain tissue from scrapie-infected hamsters and uninfected hamsters was subjected to subcellular fractionation to isolate unique tubulofilamentous particles termed "nemaviruses". Nucleic acid was purified from the concentrate by the phenol/chloroform extraction procedure and by alkaline gel electrophoresis; a single band of ssDNA corresponding to about 1.2 kb was visualized. The gel-purified ssDNA was mixed before inoculation with (a) MgCl2, (b) lipofectin, (c) ssDNA-binding protein and (d) normal brain homogenate. Hamsters in group b, c and d injected with a mixture of ssDNA developed the clinical disease. Brain pathology revealed generalized vacuolation, while animals injected with ssDNA mixed with MgCl2 and controls remained healthy. These results suggest that ssDNA is the genome of the scrapie agent.