title: Clustering of undermethylated CCGG and GCGC sequences in the 5' region of the Ha-ras-1 oncogene of human leukemic K562 cells.
abstract: The methylation state of the CCGG and GCGC sites of the Ha-ras-1 oncogene was analysed in the human leukemic K562 cell line, which was found to actively transcribe this gene. The results obtained demonstrate that the Ha-ras-1 oncogene is extensively methylated in both exonic, intronic, VTR and 3' untranslated portions, while undermethylations are present in a CG-rich island localized upstream of exon 1, near putative transcription initiation signals. Treatment of K562 cells with 5-azacytidine induces undermethylation of the Ha-ras-1 oncogene without major differences in the accumulation of Ha-ras-1 mRNA transcripts.
authors.forename: R
authors.initials: R
authors.lastname: Barbieri
authors.forename: R
authors.initials: R
authors.lastname: Piva
authors.forename: D
authors.initials: D
authors.lastname: Buzzoni
authors.forename: S
authors.initials: S
authors.lastname: Volinia
authors.forename: R
authors.initials: R
authors.lastname: Gambari
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D006801:Humans; D007951:Leukemia, Myeloid / Q000235:genetics*; D008545:Melanoma / Q000235:genetics; D008745:Methylation; D009693:Nucleic Acid Hybridization; D009857:Oncogenes; D011401:Promoter Regions, Genetic