A comparison of BKV, JCV, and SV 40 transcriptional enhancers in primate cells. Application of the two-phase partition assay for chloramphenicol acetyl transferase (CAT).

The activities of the transcriptional enhancers of the prototype human polyomaviruses, BKV (Dun) and JCV (MAD-1), were compared with that of the rhesus virus SV 40 in Old World African green monkey kidney cells (CV-1) and in New World owl monkey kidney cells (OMK). Enhancer activities were tested in CAT-expression plasmids. CAT activity in transfected cell extracts were measured by the novel two-phase partition assay. The activities of the BKV and JCV enhancers were 45% and 20% that of SV 40, respectively, in CV-1 cells. The effectiveness of each viral enhancer was less in OMK cells than in CV-1 cells, as would be expected if the viruses co-evolved with their natural hosts. In CV-1 cells, the BKV enhancer was more active than that of JCV, but in OMK cells the reverse was true. This result is significant in view of the fact that JCV, but not BKV, is oncogenic in owl monkeys.