ACTIVE DOMAINS OF HUMAN-PAPILLOMAVIRUS TYPE-11 E1 PROTEIN FOR ORIGIN REPLICATION

Viral proteins El and E2 are essential for transient human papillomavi rus (HPV) DNA replication. El is a multifunctional protein which can b ind DNA and complex with E2, has ATPase and helicase activities, and i nteracts with DNA polymerase alpha-primase. E2 is a transactivator-rep ressor protein, playing an important role in replication and transcrip tional regulation. A series of deletion mutants of HPV-11 El were cons tructed and tested in functional assays to define those domains of HPV -11 El which are important for binding to the origin DNA and E2. The d omain of HPV-11 El involved in binding to the origin was located betwe en aa 186 and 649, and that for binding to E2 was between aa 346 and 6 49. Since El binds to the origin more efficiently in the presence of E 2, we also mapped the DNA binding domain of El in the presence of E2, and found that when binding was enhanced, the region of El involved in binding was similar to that observed with El alone. The same deletion mutation constructs of El were subcloned into an expression vector fo r use in transient replication assays to study the effect of the delet ions on the replication of the origin DNA in vivo and the data suggest that the C-terminal domain contains important functions for replicati on.