FIG 2.
Selective degradation of DY PrPSc enhances the emergence of HY PrPSc from a mixture. Western blotting (A) and migration analysis (B) of PrPSc from PMCAsi reactions. Negative-control brain homogenate reactions did not amplify PrPSc (lane [Ln] 1). Positive-control PMCA reaction mixtures seeded with either HY-infected (lane 8) or DY-infected (lane 2) brain homogenate maintained the 21-kDa (lane 15) or 19-kDa (lane 9) strain-specific unglycosylated PrPSc migration pattern, respectively, following 5 rounds of amplification. Positive-control PMCAsi reaction mixtures seeded with both HY and DY (lanes 3 to 7) in the absence of PK digestion resulted in HY PrPSc emerging by round 5. Experimental PMCAsi reaction mixtures seeded with both HY and DY (lanes 10 to 14) that were digested with PK for 24 h resulted in HY PrPSc emerging in round 2. Migration of 19-kDa and 21-kDa molecular weight marker is indicated on the left of the Western blot. This experiment was repeated a minimum of 3 times with similar results.