title: Evidence for gene silencing by DNA methylation in normal human diploid fibroblasts.
abstract: Human diploid fibroblasts, strain MRC-5, were permeabilized by electroporation and treated with 5-methyl deoxycytidine triphosphate (5-methyl dCTP) in the S phase of the cell cycle. The frequency of TGR HPRT- cells was increased up to 20-fold in comparison to control untreated cultures. Representative TGR clones were unable to grow in HAT, and these were treated with 5-azacytidine (5-aza-CR). In many cases subsequent growth in HAT medium was observed, but in others it is likely that the cells had run out of growth potential. The results provide the first evidence of the silencing and reactivation of a gene in normal diploid mammalian cells.
mesh_terms: D001374:Azacitidine / Q000494:pharmacology; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D003845:Deoxycytosine Nucleotides / Q000494:pharmacology; D004171:Diploidy; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D008040:Genetic Linkage; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D008297:Male; D008745:Methylation; D014960:X Chromosome
chemical_list: D003845:Deoxycytosine Nucleotides; C034817:5-methyldeoxycytidine triphosphate; D004247:DNA; D007041:Hypoxanthine Phosphoribosyltransferase; D001374:Azacitidine