title: Transcriptional regulation mechanism mediated by miRNA-DNA•DNA triplex structure stabilized by Argonaute.
abstract: Transcription regulation depends on interactions between repressor or activator proteins with promoter sequences, while post-transcriptional regulation typically relies on microRNA (miRNA) interaction with sequences in 5' and 3'-Untranslated regions (UTRs) of messenger RNA (mRNA). However, several pieces of evidence suggest that miRNA:Argonaute (AGO) complexes may also suppress transcription through RNA interference (RNAi) components and epigenetic mechanisms. However, recent observations suggest that miRNA-induced transcriptional silencing could be exerted by an unknown mechanism independent of chromatin modifiers. The RNA-DNA•DNA triplex structure has emerged as an important RNA tertiary motif in which successive non-canonical base pairs form between a DNA-DNA duplex and a third strand. Frequently, promoters have Purine (PU)-rich tracts, and some Triplex-forming oligonucleotides (TFOs) targeting these regulatory regions have been shown to inhibit transcription selectively. Here, we summarize observations suggesting that miRNAs exert regulation over promoter regions through miRNA-DNA•DNA triplex structure formation stabilized by AGO proteins which represents a plausible model of RNA-mediated Transcriptional gene silencing (TGS).
authors.affiliation: Laboratorio de Medicina Regenerativa, Dirección de Investigación, Hospital Juárez de México, Av. Instituto Politécnico Nacional 5160, Col. Magdalena de las Salinas Del., Gustavo A. Madero, Distrito Federal C.P. 07760, Mexico.
authors.forename: Julia D
authors.initials: JD
authors.lastname: Toscano-Garibay
authors.affiliation: Laboratorio de Genómica, Genética y Bioinformática, Hospital Infantil de México Federico Gómez, Dr. Márquez No. 162, Col. Doctores, Delegación: Cuauhtémoc, México D.F. C.P. 06720, Mexico. Electronic address: guillaqui@himfg.edu.mx.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Aquino-Jarquin
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D014158:Transcription, Genetic
chemical_list: D060565:Argonaute Proteins; D035683:MicroRNAs; C051802:triplex DNA; D004247:DNA
keywords: Argonaute; Transcriptional regulation; Triple-helix structure; Triplex-forming miRNA; Triplex-forming oligonucleotide; microRNA