THE ACIDIC TRANSCRIPTIONAL ACTIVATION DOMAINS OF VP16 AND P53 BIND THE CELLULAR REPLICATION PROTEIN-A AND STIMULATE INVITRO BPV-1 DNA-REPLICATION

For papillomavirus DNA replication, the E2 enhancer protein cooperativ ely assists in binding of the E1 helicase to the origin. We report tha t, at limiting E1 and E2 levels, the enhancer proteins GAL4-VP16 and G AL4-p53(1-73) stimulate BPV in vitro DNA replication. This cell-free s ystem was used to ascertain whether the acidic activation domains have a cellular target important for replication. Cellular extracts were d epleted of replication activity by passage through a VP16 affinity col umn. The protein depleted was the cellular factor replication protein A. The direct interaction between replication protein A and VP16, as w ell as the activation of replication by VP16, is dependent upon the C- terminus of the VP16 activation domain. E2 and the activation domain o f p53 also interact with replication protein A. We suggest that a link between transcription and replication involves factors that help conv ert a closed DNA complex to an open complex.