Regulation of Epstein-Barr virus BamHI-H divergent promoter by DNA methylation.
The regulatory mechanisms which control latency and reactivation of the Epstein-Barr virus (EBV) are not fully understood. To determine whether DNA methylation is involved, we examined the BamHI-H divergent promoter, which also encompasses the origin for lytic replication (oriLyt) of EBV. The divergent promoter was highly methylated in the stringently latent HH514cl16 cell line and largely unmethylated in the semipermissive FF41-1 cell line. Expression vectors in which the divergent promoter directed transcription of the chloramphenicol acetyltransferase gene were made. Using in vitro methylation and transient transfections, we found an inverse correlation between the number of sites methylated and level of gene expression. Similar patterns of inhibition were observed when the methylated promoter was activated by BZLF1 or BRLF1 and in lymphoid or epithelial cells. The role of two CpG dinucleotides in the BRLF1 binding sites of the divergent promoter was determined by site-directed mutagenesis. The results indicated that site-specific methylation of these CpGs was not solely responsible for inhibition of expression by methylation. DNA methylation also reduced DNA replication mediated by oriLyt. These results suggest that hypermethylation of the divergent promoter and oriLyt may suppress transcription and lytic replication of EBV.
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Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
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D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002051:Burkitt Lymphoma; D002144:Callithrix; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000378:metabolism; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism*; D015245:Deoxyribonuclease BamHI; D015226:Dinucleoside Phosphates / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D006367:HeLa Cells; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D008745:Methylation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
D015500:Chloramphenicol O-Acetyltransferase; D004279:DNA, Viral; D015245:Deoxyribonuclease BamHI; D015226:Dinucleoside Phosphates; D009838:Oligodeoxyribonucleotides; C015772:CpG dinucleotide