2 E2 BINDING-SITES (E2BS) ALONE OR ONE E2BS PLUS AN A T-RICH REGION ARE MINIMAL REQUIREMENTS FOR THE REPLICATION OF THE HUMAN PAPILLOMAVIRUS TYPE-11 ORIGIN/

Human papillomaviruses (HPVs) cannot be propagated in vitro, but the D NA can be replicated transiently in an assay in the presence of two tr ans-acting viral proteins, E1 and E2. Using this assay, we have define d the minimal cis-acting elements of the origin of replication of HPV type 11. Most HPV genomes are conserved at the origin of replication, and the core contains three E2 binding sites (E2BS) surrounding an A/T -rich spacer region. The present results show that the minimal require ment for replication is either two E2BS alone or the A/T-rich region p lus one E2BS; in the latter case the relative position of the E2BS is important. In all the studies, the presence of both E1 and E2 proteins was essential for replication, yet only the E2BS was required at the origin. We have shown that E1, E2, and the origin of replication conta ining an E2BS from a complex in vitro, and our data are consistent wit h a model in which E2 acts to target E1 to the HPV type 11 replication origin.