title: The methylation pattern of normal and truncated amplified human c-myc oncogenes.
abstract: COLO320DM and COLO320HSR are two human cell lines with 30-40-fold c-myc amplification. Half of the c-myc gene copies in COLO320DM are truncated and expressed as the predominant mRNA, while half are normal. Most c-myc copies in COLO320HSR are normal and expressed. Truncated c-myc genes are fully methylated, while the normal ones are fully demethylated irrespective of their stage of expression. The normal transcriptionally active c-myc from fibroblast cells is fully methylated, while c-myc from granulocytes (probably downregulated) is almost fully demethylated. These results indicate a lack of correlation between expression and the state of methylation for human c-myc oncogenes. Furthermore, exons 1 and 2 and intron 1 of c-myc are CpG-rich islands. Since these islands are constitutively demethylated, it is assumed that demethylation is the constitutive state and methylation the facultative state of the c-myc oncogene.
authors.affiliation: IMBICE, La Plata, Argentina.
authors.forename: N O
authors.initials: NO
authors.lastname: Bianchi
authors.forename: M S
authors.initials: MS
authors.lastname: Bianchi
authors.forename: K
authors.initials: K
authors.lastname: Alitalo
authors.forename: A
authors.initials: A
authors.lastname: de la Chapelle
mesh_terms: D001482:Base Composition; D005091:Exons; D005347:Fibroblasts / Q000502:physiology; D005784:Gene Amplification; D005786:Gene Expression Regulation; D005796:Genes; D006098:Granulocytes / Q000502:physiology; D006801:Humans; D008745:Methylation; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D015183:Restriction Mapping; D014407:Tumor Cells, Cultured
chemical_list: D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc