Biochemistry, Department of
Date of this Version
1-1-2005
Abstract
The field of epigenetics is the study of modifications of DNA and DNA-binding proteins that alter the structure of chromatin without altering the nucleotide sequence of DNA; some of these modifications may be associated with heritable changes in gene function. Nutrients play essential roles in the following epigenetic events. First, folate participates in the generation of S-adenosylmethionine, which acts as a methyl donor in the methylation of cytosines in DNA; methylation of cytosines is associated with gene silencing. Second, covalent attachment of biotin to histones (DNA-binding proteins) plays a role in gene silencing and in the cellular response to DNA damage. Third, tryptophan and niacin are converted to nicotinamide adenine dinucleotide, which is a substrate for poly(ADP-ribosylation) of histones and other DNA-binding proteins; poly(ADP-ribosylation) of these proteins participates in DNA repair and apoptosis. Here we present a novel procedure to map nutrient-dependent epigenetic marks in the entire genomes of any given species: the combined use of chromatin immunoprecipitation assays and DNA microarrays. This procedure is also an excellent tool to map the enzymes that mediate modifications of DNA and DNA-binding proteins in chromatin. Given the tremendous opportunities offered by the combined use of chromatin immunoprecipitation assays and DNA microarrays, the nutrition community can expect seeing a surge of information related to roles for nutrients in epigenetic events.
Comments
Published in Journal of Nutritional Biochemistry 16 (2005) 74– 77.