A bifunctional baculovirus homologous region (hr1) sequence: enhancer and orginal of replication functions reside within the same sequence element

Abstract

Analysis of the synergy between transcription regulation and DNA replication as well as the mechanisms of enhancer action has been of interest to us. Our studies on the Autographa californica multi-nucleocapsid nuclear polyhedrosis virus (AcMNPV) have revealed that the viral homologous region sequence, hr1, can function as an enhancer of polyhedron promoter-driven transcription as well as an origin of DNA replication in transfected host insect cells. Minimal sequence requirements for both these activities of hr1 have been delineated. A host factor that interacts at multiple sites within hr1 has also been implicated in the enhancer function of this sequence. While demonstrating the dual function of hr1, our observations also indicate the importance of host factor(s) in regulating crucial processes in the viral infection cycle.