2 PARVOVIRUSES THAT CAUSE DIFFERENT DISEASES IN MINK HAVE DIFFERENT TRANSCRIPTION PATTERNS - TRANSCRIPTION ANALYSIS OF MINK ENTERITIS VIRUSAND ALEUTIAN MINK DISEASE PARVOVIRUS THE SAME CELL-LINE

The two parvoviruses of mink cause very different diseases, Mink enter itis virus (MEV) is associated with rapid, high-level viral replicatio n and acute disease, In contrast, infection with Aleutian mink disease parvovirus (ADV) is associated with persistent, low-level viral repli cation and chronic severe immune dysregulation, In the present report, we have compared viral transcription in synchronized CRFK cells infec ted with either MEV or ADV using a nonradioactive RNase protection ass ay, The overall level of viral transcription was 20-fold higher in MEV - than in ADV-infected cells. Furthermore, MEV mRNA encoding structura l proteins (MEV mRNA R3) was dominant throughout the infectious cycle, comprising approximately 80% of the total viral transcription product s, In marked contrast, in ADV-infected cells, transcripts encoding non structural proteins (ADV mRNA R1 and R2) comprised more than 84% of th e total transcripts at all times after infection? whereas ADV mRNA R3 comprised less than 16%, Thus, the ADV mRNA coding for structural prot eins (ADV mRNA R3) was present at a level at least 100-fold lower than the corresponding MEV mRNA R3, These findings paralleled previous bio chemical studies analysing in vitro activities of the ADV and MEV prom oters (J. Christensen. T. Storgaard, E. Viuff, B. Aasted, and S. Alexa ndersen, J. Virol. 67:1877-1886, 1993). The overall low levels of ADV mRNA and the paucity of the mRNA coiling for ADV structural proteins m ay reflect an adaptation of the virus for low-level restricted infecti on.