Papers In Press, published online ahead of print September 6, 2006
J. Biol. Chem, 10.1074/jbc.M600468200
Submitted on January 17, 2006
Revised on August 30, 2006
Accepted on September 6, 2006
Epstein-Barr virus induces cellular transcription factors to allow active expression of EBER genes by RNA polymerase III
Zoe A. Felton-Edkins, Alexander Kondrashov, Dimitra Karali, Jennifer A. Fairley, Christopher W. Dawson, John R. Arrand, Lawrence S. Young, and Robert J. White
Biochemistry and Molecular Biology, University of Glasgow, Glasgow G12 8QQ
Corresponding Author: rwhite{at}udcf.gla.ac.uk
The EBER genes of Epstein-Barr virus (EBV) are transcribed by RNA polymerase (pol) III to produce untranslated RNAs that are implicated in oncogenesis. These EBER transcripts are the most highly expressed viral gene products in EBV-transformed cells. We have identified changes to the cellular transcription machinery that may contribute to the high levels of EBER RNA. These include phosphorylation of ATF2, which interacts with EBER promoters. A second is induction of TFIIIC, a pol III-specific factor that activates EBER genes; all five subunits of TFIIIC are overexpressed in EBV-positive cells. In addition, EBV induces Bdp1, a subunit of the pol III-specific factor TFIIIB. Although Bdp1 is the only TFIIIB subunit induced by EBV, its induction is sufficient to stimulate EBER expression in vivo, implying a limiting function. The elevated levels of Bdp1 and TFIIIC in EBV-positive cells stimulate production of tRNA, 7SL and 5S rRNA. Abnormally high expression of these cellular pol III products may contribute to the ability of EBV to enhance growth potential.