Efficient transfection of novel bovine papillomavirus 1 expression plasmids

A series of novel bovine papillomavirus type 1 (BPV-1)-based expression plasmids was constructed and characterized in vitro as a starting point for the development of an in vivo gene therapeutic method. The order of transfection efficiency for different pBPVlacZ plasmids was pCGalBPV > pTKBPV > pSRalphaBPV in CV1-P cells. In the absence of selection pressure, the expression of pCGalBPVlacZ and pTKBPVlacZ was associated with long-term maintenance. In a comparison of pBPVlacZ with pSVlacZ, expression was maintained up to 12-17 and 8-12 days, respectively. The transfection of pBPVlacZ plasmids was efficient in secondary and primary, dividing and nondividing, neural and nonneural, and human cells and, furthermore, independent of the cell cycle as seen in growing as well as resting cells. All these characteristics are likely to be relevant for in vivo conditions, under which the percentage of proliferating cells could be quite low. In conclusion, the pBPV plasmids were efficiently delivered and expressed in different host cells, and therefore their performance in gene therapy is worth testing.