title: Transient cyclical methylation of promoter DNA.
abstract: Methylation of CpG dinucleotides is generally associated with epigenetic silencing of transcription and is maintained through cellular division. Multiple CpG sequences are rare in mammalian genomes, but frequently occur at the transcriptional start site of active genes, with most clusters of CpGs being hypomethylated. We reported previously that the proximal region of the trefoil factor 1 (TFF1, also known as pS2) and oestrogen receptor alpha (ERalpha) promoters could be partially methylated by treatment with deacetylase inhibitors, suggesting the possibility of dynamic changes in DNA methylation. Here we show that cyclical methylation and demethylation of CpG dinucleotides, with a periodicity of around 100 min, is characteristic for five selected promoters, including the oestrogen (E2)-responsive pS2 gene, in human cells. When the pS2 gene is actively transcribed, DNA methylation occurs after the cyclical occupancy of ERalpha and RNA polymerase II (polII). Moreover, we report conditions that provoke methylation cycling of the pS2 promoter in cell lines in which pS2 expression is quiescent and the proximal promoter is methylated. This coincides with a low-level re-expression of ERalpha and of pS2 transcripts.
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
authors.forename: Sara
authors.initials: S
authors.lastname: Kangaspeska
authors.forename: Brenda
authors.initials: B
authors.lastname: Stride
authors.forename: Raphaël
authors.initials: R
authors.lastname: Métivier
authors.forename: Maria
authors.initials: M
authors.lastname: Polycarpou-Schwarz
authors.forename: David
authors.initials: D
authors.lastname: Ibberson
authors.forename: Richard Paul
authors.initials: RP
authors.lastname: Carmouche
authors.forename: Vladimir
authors.initials: V
authors.lastname: Benes
authors.forename: Frank
authors.initials: F
authors.lastname: Gannon
authors.forename: George
authors.initials: G
authors.lastname: Reid
mesh_terms: D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D047628:Estrogen Receptor alpha; D012333:RNA, Messenger; C051838:TFF1 protein, human; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; D004317:Doxorubicin; D004247:DNA; D012319:RNA Polymerase II