CpG-methylation silences the activity of the RNA polymerase III transcribed EBER-1 promoter of Epstein-Barr virus

CpG-methylation blocks the activity of RNA polymerase II transcribed promoters in most cases. In contrast, the role of DNA methylation in the regulation of RNA polymerase III transcribed promoters is less clarified. There are two untranslated viral RNAs (EBER-1 and EBER-2) in most malignant cells carrying latent Epstein-Barr virus (EBV) genomes. We found that in vitro methylation blocked binding of the cellular proteins c-Myc and ATF to the 5'-region of the EBER-1 gene, and silenced the expression of the EBER-1 and EBER-2 genes, transcribed by RNA polymerase III, in transfected cells.