RNA insertions and gene duplications in the nonstructural protein p125 region of pestivirus strains and isolates in vitro and in vivo.

Sixteen cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strains/isolates were screened for the existence of RNA insertions in the p125 gene region and/or for p80 gene duplications using the polymerase chain reaction after reverse transcription. Three strains/isolates were shown to contain insertions, and in three others gene duplications were demonstrated. One strain was shown to contain a gene duplication in addition to an insertion. Insertions or duplications were absent in the genomes of 10 non-cp BVD virus strains/isolates, in 4 hog cholera (HC) virus strains, and in 9 of the 16 cp BVD virus strains/isolates analyzed. These results indicate that RNA insertions and gene duplications, although significant, are not the only mechanism contributing to cytopathogenicity in vitro. The RT-PCR was also applied to RNA isolated from tissues of a calf suffering from mucosal disease. Insertion-containing amplification products could be demonstrated in an organ-specific pattern.