In vitro and in vivo translational efficiencies of the 5' untranslated region from eight genotype 2 bovine viral diarrhea virus field isolates.

We determined the in vitro and in vivo translational efficiency mediated by the internal ribosomal entry site (IRES) from eight BVDV2 field isolates varying in virulence using a bicistronic reporter vector in rabbit reticulocyte lysates (RRL), and in primate and bovine cell lines. Using a T7-promoter system, the high virulence isolates had greater translational efficiencies in bovine lymphocytes (BL-3 cells), than did the low virulence isolates. The low virulence isolates translated with greater efficiencies than the high virulence isolates in RRL, African green monkey kidney (CV-1) and bovine turbinate (BT) cells. Our results demonstrate that despite a high degree of sequence identity in the 5' untranslated region (UTR), subtle differences in the primary and secondary structures, as well as differences in cell lines, influence translational efficiencies.