title: Cellular differentiation, cytidine analogs and DNA methylation.
abstract: The nucleoside analog 5-azacytidine (5-aza-CR) induced marked changes in the differentiated state of cultured mouse embryo cells and also inhibited the methylation of newly synthesized DNA. The DNA strand containing 5-aza-CR remained undermethylated in the round of DNA synthesis following analog incorporation. The extent of inhibition of DNA modification and induction of muscle cells in treated cultures were dependent on the 5-aza-CR concentration over a narrow dose range. Experiments with the restriction enzyme Hpa II, which is sensitive to cytosine methylation in the sequence CCGG, demonstrated that the DNA synthesized in 5-aza-CR-treated cultures was maximally undermethylated 48 hr after treatment. Three other analogs of cytidine, containing a modification in the 5 position of the pyrimidine ring [5-aza-2'-deoxycytidine(5-aza-CdR), pseudoisocytidine (psi ICR) and 5-fluoro-2'-deoxycytidine(FCdR)] also induced the formation of muscle cells and inhibited DNA methylation. In contrast, 1-beta-D-arabinofuranosylcytosine (araC) and 6-azacytidine (6-aza-CR) did not inhibit DNA methylation or induce muscle formation, whereas 5-6-dihydro-5-azacytidine (dH-aza-CR) was a poor inducer of muscle cells and a poor inhibitor of DNA methylation. These results provide experimental evidence for a role for DNA modification in differentiation, and suggest that cytidine analogs containing an altered 5 position perturb previously established methylation patterns to yield new cellular phenotypes.
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000818:Animals; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D003561:Cytarabine / Q000494:pharmacology; D003562:Cytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004247:DNA / Q000235:genetics*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D000077209:Decitabine; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism*; D051379:Mice; D009132:Muscles / Q000166:cytology; D013329:Structure-Activity Relationship
chemical_list: D003561:Cytarabine; D003841:Deoxycytidine; D003562:Cytidine; D000077209:Decitabine; D004247:DNA; D008780:Methyltransferases; D004248:DNA (Cytosine-5-)-Methyltransferases; C007746:5-fluoro-2'-deoxycytidine; D001374:Azacitidine; C012518:pseudoisocytidine