FAILURE TO TRANSMIT DISEASE FROM GRAY TREMOR MUTANT MICE

Mice homozygous for mutant alleles at the gray tremor (gt) locus devel op a marked non-intention tremor beginning at 8 days of age, Most homo zgous mice die by 3 months. Homozygotes exhibit intense vacuolation of the central nervous system gray matter and vacuolation and hypomyelin ation of some white matter tracts, Based on neuropathological similari ties with scrapie, other investigators inoculated wild-type mice with gray tremor brain homogenates to test the hypothesis of transmissibili ty, Published reports indicated that spongiform encephalopathy. (R. L. Sidman, H. C. Kinney, and H. O. Sweet, Proc. Natl. Acad. Sci. USA 82: 253-257, 1985) and disease, including hind limb paralysis in NFS mice (P. M. Hoffman, R. G. Rohwer, C. MacAuley, J. A. Bilello, J. W. Hartle y, and H. C. Morse III, Proc. Natl. Acad. Sci. USA 84:3866-3870, 1987) , were transmitted by inoculation of gt/gt brain homogenates, In our h ands, however, no NFS/NCr animals inoculated intracerebrally with gt/g t or +/+ brain preparations showed any signs of disease or pathologica l changes in the brain, Positive transmission by other investigators m ay reflect the microbiological status of their donor or recipient mice .