Clustering of undermethylated CCGG and GCGC sequences in the 5' region of the Ha-ras-1 oncogene of human leukemic K562 cells.
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.
Barbieri
R
R
Piva
R
R
Buzzoni
D
D
Volinia
S
S
Gambari
R
R
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