title: DNA-osmium complexes: recent developments in the operative chemical analysis of DNA epigenetic modifications.
abstract: The development of a reaction for the detection of one epigenetic modification in a long DNA strand is a chemically and biologically challenging research subject. Herein, we report and discuss the formation of 5-methylcytosine-osmium complexes that are used as the basis for a bisulfite-free chemical assay for DNA methylation analysis. Osmium in the oxidized state reacts with C5-methylated pyrimidines in the presence of a bipyridine ligand to give a stable ternary complex. On the basis of this reaction, an adenine derivative with a tethered bipyridine moiety has been designed for sequence-specific osmium complex formation. Osmium complexation is then achieved by hybridization of a short DNA molecule containing this functional nucleotide to a target DNA sequence and results in the formation of a cross-linked structure. This novel concept of methylation-specific reaction, based on a straightforward chemical process, expands the range of methods available for the analysis of epigenetic modifications. Advantages of the described method include amplification-insensitive detection, 5-hydroxymethylcytosine complexation, and visualization through methylation-specific in situ hybridization.
authors.affiliation: Research Center for Advanced Science & Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan). okamoto@chembio.t.u-tokyo.ac.jp.
authors.forename: Akimitsu
authors.initials: A
authors.lastname: Okamoto
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry* / Q000187:drug effects; D019175:DNA Methylation / Q000187:drug effects; D044127:Epigenesis, Genetic; D057890:Epigenomics / Q000379:methods*; D006801:Humans; D017892:Osmium Compounds / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D017892:Osmium Compounds; D004247:DNA
keywords: DNA methylation; epigenetics; fluorescent probes; genomics; osmium