Epigenetics of latent Epstein-Barr virus genomes: high resolution methylation analysis of the bidirectional promoter region of latent membrane protein 1 and 2B genes.
We analysed the methylation patterns of CpG dinucleotides in a bidirectional promoter region (LRS, LMP 1 regulatory sequences) of latent Epstein-Barr virus (EBV) genomes using automated fluorescent genomic sequencing after bisulfite-induced modification of DNA. Transcripts for two latent membrane proteins, LMP 1 (a transforming protein) and LMP 2B, are initiated in this region in opposite directions. We found that B cell lines and a clone expressing LMP 1 carried EBV genomes with unmethylated or hypomethylated LRS, while highly methylated CpG dinucleotides were present at each position or at discrete sites and within hypermethylated regions in LMP 1 negative cells. Comparison of high resolution methylation maps suggests that CpG methylation-mediated direct interference with binding of nuclear factors LBF 2, 3, 7, AML1/LBF1, LBF5 and LBF6 or methylation of CpGs within an E-box sequence (where activators as well as repressors can bind) is not the major mechanism in silencing of the LMP 1 promoter. Although a role for CpG methylation within binding sites of Sp1 and 3, ATF/CRE and a sis-inducible factor (SIF) cannot be excluded, hypermethylation of LRS or regions within LRS in LMP 1 negative cells suggests a role for an indirect mechanism, via methylcytosine binding proteins, in silencing of the LMP 1 promoter.
Takacs
M
M
Division of Virology, National Center for Epidemiology, Budapest, Hungary.
Salamon
D
D
Myöhänen
S
S
Li
H
H
Segesdi
J
J
Ujvari
D
D
Uhlig
J
J
Niller
H H
HH
Wolf
H
H
Berencsi
G
G
Minarovits
J
J
D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D004279:DNA, Viral / Q000302:isolation & purification*; D016679:Genome, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017421:Sequence Analysis; D014763:Viral Matrix Proteins / Q000235:genetics*; D017735:Virus Latency
D004279:DNA, Viral; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D014763:Viral Matrix Proteins