title: Methylation of miRNA genes and oncogenesis.
abstract: Interaction between microRNA (miRNA) and messenger RNA of target genes at the posttranscriptional level provides fine-tuned dynamic regulation of cell signaling pathways. Each miRNA can be involved in regulating hundreds of protein-coding genes, and, conversely, a number of different miRNAs usually target a structural gene. Epigenetic gene inactivation associated with methylation of promoter CpG-islands is common to both protein-coding genes and miRNA genes. Here, data on functions of miRNAs in development of tumor-cell phenotype are reviewed. Genomic organization of promoter CpG-islands of the miRNA genes located in inter- and intragenic areas is discussed. The literature and our own results on frequency of CpG-island methylation in miRNA genes from tumors are summarized, and data regarding a link between such modification and changed activity of miRNA genes and, consequently, protein-coding target genes are presented. Moreover, the impact of miRNA gene methylation on key oncogenetic processes as well as affected signaling pathways is discussed.
authors.affiliation: Institute of General Pathology and Pathophysiology, Moscow, 125315, Russia. eleonora10_45@mail.ru.
authors.forename: V I
authors.initials: VI
authors.lastname: Loginov
authors.forename: S V
authors.initials: SV
authors.lastname: Rykov
authors.forename: M V
authors.initials: MV
authors.lastname: Fridman
authors.forename: E A
authors.initials: EA
authors.lastname: Braga
mesh_terms: D063646:Carcinogenesis / Q000235:genetics* / Q000378:metabolism; D018899:CpG Islands; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D005796:Genes; D035683:MicroRNAs / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000235:genetics
chemical_list: D035683:MicroRNAs