title: MIR-206 regulates connexin43 expression during skeletal muscle development.
abstract: Skeletal myoblast fusion in vitro requires the expression of connexin43 (Cx43) gap junction channels. However, gap junctions are rapidly downregulated after the initiation of myoblast fusion in vitro and in vivo. In this study we show that this downregulation is accomplished by two related microRNAs, miR-206 and miR-1, that inhibit the expression of Cx43 protein during myoblast differentiation without altering Cx43 mRNA levels. Cx43 mRNA contains two binding sites for miR-206/miR-1 in its 3'-untranslated region, both of which are required for efficient downregulation. While it has been demonstrated before that miR-1 is involved in myogenesis, in this work we show that miR-206 is also upregulated during perinatal skeletal muscle development in mice in vivo and that both miR-1 and miR-206 downregulate Cx43 expression during myoblast fusion in vitro. Proper development of singly innervated muscle fibers requires muscle contraction and NMJ terminal selection and it is hypothesized that prolonged electrical coupling via gap junctions may be detrimental to this process. This work details the mechanism by which initial downregulation of Cx43 occurs during myogenesis and highlights the tight control mechanisms that are utilized for the regulation of gap junctions during differentiation and development.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miller School of Medicine, Gautier Building 303, 1011 NW 15 Street, Miami, FL 33136, USA.
authors.forename: Curtis
authors.initials: C
authors.lastname: Anderson
authors.forename: Heath
authors.initials: H
authors.lastname: Catoe
authors.forename: Rudolf
authors.initials: R
authors.lastname: Werner
mesh_terms: D020413:3' Untranslated Regions / Q000737:chemistry; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D019295:Computational Biology; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000032:analysis / Q000502:physiology*; D008969:Molecular Sequence Data; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D020413:3' Untranslated Regions; D018031:Connexin 43; D035683:MicroRNAs