Stimulation of DNA Replication from the Polyomavirus Origin by PCAF and GCN5 Acetyltransferases: Acetylation of Large T Antigen

Abstract

The PCAF and GCN5 acetyltransferases, but not p300 or CBP, stimulate DNA replication when tethered near the polyomavirus origin. Replication stimulation by PCAF and GCN5 is blocked by mutational inactivation of their acetyltransferase domains but not by deletion of sequences that bind p300 or CBP. Acetylation of histones near the polyomavirus origin assembled into chromatin in vivo is not detectably altered by expression of these acetyltransferases. PCAF and GCN5 interact with polyomavirus large T antigen in vivo, PCAF acetylates large T antigen in vitro, and large T-antigen acetylation in vivo is dependent upon the integrity of the PCAF acetyltransferase domain. These data suggest replication stimulation occurs through recruitment of large T antigen to the origin and acetylation by PCAF or GCN5.

We thank the members of the Folk laboratory for helpful suggestions and Sarah Scanlon for her invaluable assistance. We also thank S. L. Berger for GCN5_SF expression vectors, J. C. Chrivia for pRc/RSVGalCBPFL-flag, S. Y. Dent for pCMVSPORT2mGCN5fl, A. J. Giordano for pcDNA3Galp300, B. Milavetz for pBM129, and X. J. Yang for PCAF expression vectors. We are greatly indebted to S. L. Berger and S. Y. Dent for insightful discussions during the course of these studies and for their suggestions about the manuscript.

This work was supported in part by National Institutes of Health grant R01 CA38538, U.S. Army grant DAMD17-98-1-8321, and by the University of Missouri—Columbia.