Stable maintenance of linear bovine papillomavirus 1 molecules in C127I cells

This paper describes the characterization of cell lines that stably maintai n linear copies of bovine papillomavirus 1 (BPV-1). Cell lines were generat ed by liposome-mediated transfection of BamH1-linearized virus into C127I c ells. Two transfectants with morphologies differing from each other and fro m that of the parental cell line were characterized. Southern blots indicat ed that they contain ten to twelve copies of the BPV-1 genome per cell and that the predominant species in both cell Lines are linear BPV-1 episomes. One to two copies per genome of a slow migrating species are also present. Both BPV-1 species found in these cells are sensitive to BAL31 digestion. V iral chromosomal ends were amplified by anchored PCR, cloned and sequenced. Our results indicate that no major rearrangements have occurred in the seq uence flanking the BamH1 site where the virus used for transfection was lin earized. No circular BPV-1 molecules were detected by PCR. The slow migrati ng species may serve as templates for replication for the linear forms by a yet unidentified mechanism.