title: Methylation of chromatin in vitro.
abstract: The endogenous DNA methylase in nuclei isolated from growing mouse cells preferentially methylates DNA in micrococcal nuclease-resistant regions probably as a result of the location in these regions of the preponderance of hemimethylated sites. Added mouse ascites cell DNA methylase catalyses the methylation of exposed, nuclease-sensitive DNA in chromatin from growing or non-growing mouse or insect cells. The poor acceptor ability of nuclease-resistant regions in this situation is due to the presence of histone proteins which block de novo methylation. Transcriptionally active regions of chromatin are selectively methylated in vitro by either endogenous or added DNA methylase.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000032:analysis; D006609:High Mobility Group Proteins / Q000494:pharmacology; D008745:Methylation; D051379:Mice; D009698:Nucleoproteins / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D006609:High Mobility Group Proteins; D009698:Nucleoproteins; D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases