title: Specification of skeletal muscle differentiation by repressor element-1 silencing transcription factor (REST)-regulated Kv7.4 potassium channels.
abstract: Changes in the expression of potassium (K(+)) channels is a pivotal event during skeletal muscle differentiation. In mouse C(2)C(12) cells, similarly to human skeletal muscle cells, myotube formation increased the expression of K(v)7.1, K(v)7.3, and K(v)7.4, the last showing the highest degree of regulation. In C(2)C(12) cells, K(v)7.4 silencing by RNA interference reduced the expression levels of differentiation markers (myogenin, myosin heavy chain, troponinT-1, and Pax3) and impaired myotube formation and multinucleation. In K(v)7.4-silenced cells, the differentiation-promoting effect of the K(v)7 activator N-(2-amino-4-(4-fluorobenzylamino)-phenyl)-carbamic acid ethyl ester (retigabine) was abrogated. Expression levels for the repressor element-1 silencing transcription factor (REST) declined during myotube formation. Transcript levels for K(v)7.4, as well as for myogenin, troponinT-1, and Pax3, were reduced by REST overexpression and enhanced upon REST suppression by RNA interference. Four regions containing potential REST-binding sites in the 5' untranslated region and in the first intron of the K(v)7.4 gene were identified by bioinformatic analysis. Chromatin immunoprecipitation assays showed that REST binds to these regions, exhibiting a higher efficiency in myoblasts than in myotubes. These data suggest that K(v)7.4 plays a permissive role in skeletal muscle differentiation and highlight REST as a crucial transcriptional regulator for this K(+) channel subunit.
authors.affiliation: Division of Pharmacology, Department of Neuroscience, University of Naples Federico II, 80131 Naples, Italy.
authors.forename: Fabio Arturo
authors.initials: FA
authors.lastname: Iannotti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barrese
authors.forename: Luigi
authors.initials: L
authors.lastname: Formisano
authors.forename: Francesco
authors.initials: F
authors.lastname: Miceli
authors.forename: Maurizio
authors.initials: M
authors.lastname: Taglialatela
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D001665:Binding Sites; D002219:Carbamates / Q000494:pharmacology; D002454:Cell Differentiation; D002460:Cell Line; D055785:Gene Knockdown Techniques; D051656:KCNQ Potassium Channels / Q000235:genetics* / Q000378:metabolism; D049990:Membrane Transport Modulators / Q000494:pharmacology; D051379:Mice; D024510:Muscle Development; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000166:cytology; D010655:Phenylenediamines / Q000494:pharmacology; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D000099229:RE1-Silencing Transcription Factor
chemical_list: D020121:5' Untranslated Regions; D002219:Carbamates; D051656:KCNQ Potassium Channels; D049990:Membrane Transport Modulators; D010655:Phenylenediamines; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D000099229:RE1-Silencing Transcription Factor; C492167:Kcnq4 protein, mouse; C101866:ezogabine