FIG. 2.

The lcr/tk hybrid promoter retains the enhanced epithelial response of the BPV-4 promoter to upstream activators. PalK and PalF cells were cotransfected with the indicated amounts of pCMV HPV16-E2 and pCGVP16-E2 expression vectors and 1 μg of either the PV2 6E2 (A), tk 6E2 (B), or lcr/tk 6E2 (C) reporter construct. The total amount of DNA transfected was made equal in each case with pCMV or pCG containing no insert. Results are expressed as fold transactivation relative to the luciferase activity in the absence of E2 or VP16-E2 expression vector.