title: Enzymatic approaches and bisulfite sequencing cannot distinguish between 5-methylcytosine and 5-hydroxymethylcytosine in DNA.
abstract: DNA cytosine methylation (5mC) is highly abundant in mammalian cells and is associated with transcriptional repression. Recently, hydroxymethylcytosine (hmC) has been detected at high levels in certain human cell types; however, its roles are unknown. Due to the structural similarity between 5mC and hmC, it is unclear whether 5mC analyses can discriminate between these nucleotides. Here we show that 5mC and hmC are experimentally indistinguishable using established 5mC mapping methods, thereby implying that existing 5mC data sets will require careful re-evaluation in the context of the possible presence of hmC. Potential differential enrichment of 5mC and hmC DNA sequences may be facilitated using a 5mC monoclonal antibody.
authors.affiliation: MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, Scotland.
authors.forename: Colm
authors.initials: C
authors.lastname: Nestor
authors.forename: Alexey
authors.initials: A
authors.lastname: Ruzov
authors.forename: Richard
authors.initials: R
authors.lastname: Meehan
authors.forename: Donncha
authors.initials: D
authors.lastname: Dunican
mesh_terms: D044503:5-Methylcytosine / Q000737:chemistry* / Q000031:analogs & derivatives; D018899:CpG Islands; D003596:Cytosine / Q000031:analogs & derivatives* / Q000737:chemistry; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D019175:DNA Methylation; D004262:DNA Restriction Enzymes / Q000378:metabolism; D019398:Genes, BRCA1; D006801:Humans; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA / Q000379:methods*; D013447:Sulfites
chemical_list: D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D013447:Sulfites; C011865:5-hydroxymethylcytosine; D044503:5-Methylcytosine; D003596:Cytosine; D004247:DNA; D004262:DNA Restriction Enzymes; C042345:hydrogen sulfite