TRANSCRIPTION-POSITIVE COFACTOR-4 ENHANCES RESCUE OF ADENOASSOCIATED VIRUS GENOME FROM AN INFECTIOUS CLONE

While Rep proteins are required for adenoassociated virus (AAV) replic ation, little is known about cellular proteins that interact with Rep. We demonstrate here that transcription-positive cofactor 4 (PC4, p15) fused to Gal4-activating domain interacted with both AAV-2 and AAV-3 Rep proteins fused to Gal4 DNA-binding domain, leading to reporter act ivation in the:yeast two-hybrid system. In addition to its coactivatin g function, PC4 recently has been shown to be involved in replication of simian virus 40. To study a functional role for the PC4-Rep protein interaction, 293-31 cells were cotransfected with a PC4 expression pl asmid and an infectious clone of AAV-3, followed by superinfection wit h helper adenovirus. A significantly increased number of AAV-3 genomes were rescued in PC4 transfected cells. Our results support a possible involvement of PC4 in AAV replication and may be used in efficient pr oduction of AAV vectors for gene therapy.