title: Methyl group acceptance assay for the determination of global DNA methylation levels.
abstract: DNA methylation levels are affected by numerous environmental influences, including diet and xenobiotic exposure, and neoplasia has been firmly associated with genomic hypomethylation and localized hypermethylation of tumor suppressor genes. To reverse methylation-induced gene repression, DNA hypomethylating agents are currently in clinical trials for various malignancies, with two of these now approved for the therapy of myelodysplastic syndrome, and the efficacy of these drugs can be assessed by the monitoring of global DNA methylation levels. Herein, we outline a simple, well-established method for the evaluation of genomic DNA methylation levels, based on the ability of isolated DNA to "accept" radiolabeled methyl groups from S-[3H-methyl] adenosylmethionine, using the bacterial CpG methyltransferase SssI. As this enzyme methylates all unmethylated CpG dinucleotides in the genome, radiolabeled methyl group acceptance is inversely proportional to the level of preexisting methylation. This assay is applicable to a number of translational and basic research questions.
authors.affiliation: Department of Cellular and Integrative Physiology, Medical Sciences Program, Indiana University School of Medicine, Bloomington, IN, USA.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Nephew
authors.forename: Curt
authors.initials: C
authors.lastname: Balch
authors.forename: David G
authors.initials: DG
authors.lastname: Skalnik
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D018899:CpG Islands; D004247:DNA / Q000737:chemistry / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D016147:Genes, Tumor Suppressor; D009190:Myelodysplastic Syndromes / Q000235:genetics; D009369:Neoplasms / Q000737:chemistry / Q000235:genetics
chemical_list: D004273:DNA, Neoplasm; D004247:DNA