title: Intragenomic distribution of 5-methylcytosine in various forms of human and murine leukemic cells.
abstract: The degree of 5-methylcytosine formation in DNA sequences differing in reassociation rate and susceptibility to DNase II digestion has been investigated in human chronic myelogenic leukemia and acute leukemia leukocytes, human PHA-stimulated lymphocytes and murine L5178Y lymphoblasts cultured in various phases of growth. The results indicate that in all forms of cells studied by us the general pattern of intragenomic 5-methylcytosine distribution is similar, with two preferentially methylated regions: the sequences fast reassociating and rendered Mg++-soluble after DNase II digestion of nuclei. The most variable fraction as regards the level of methylation seemed to be DNA of Mg++-soluble fraction of DNase II digest, which in acute leukemia leukocytes, PHA-stimulated lymphocytes and exponentially growing L5178Y cells revealed about twice greater relative proportion of methylated cytosines than in leukocytes of chronic myelogenic leukemia and L5178Y cells maintained at saturation density.
mesh_terms: D044503:5-Methylcytosine; D000818:Animals; D002843:Chromatin / Q000032:analysis; D003596:Cytosine / Q000031:analogs & derivatives* / Q000032:analysis*; D004273:DNA, Neoplasm / Q000032:analysis* / Q000096:biosynthesis; D003851:Deoxyribonucleases; D006801:Humans; D007938:Leukemia / Q000032:analysis* / Q000097:blood; D007940:Leukemia L5178 / Q000032:analysis; D007962:Leukocytes / Q000032:analysis; D008214:Lymphocytes / Q000032:analysis; D008274:Magnesium; D008745:Methylation; D051379:Mice; D010835:Phytohemagglutinins; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D004273:DNA, Neoplasm; D010835:Phytohemagglutinins; D044503:5-Methylcytosine; D003596:Cytosine; D003851:Deoxyribonucleases; D008274:Magnesium