title: Connexin43 repression following epithelium-to-mesenchyme transition in embryonal carcinoma cells requires Snail1 transcription factor.
abstract: Embryonic stem (ES) cells and embryonal carcinoma (EC) cells express high amounts of functional connexin43 (Cx43). During mesoderm formation and subsequent cardiac differentiation, Cx43 is initially down-regulated but is up-regulated again as the emerging cardiomyocytes mature. In this study, we investigated the regulation of Cx43 expression during early phases of differentiation in F9 and P19 EC cells. We found a striking inverse correlation between the expression of Cx43 and that of the transcriptional repressor Snail1. No clear relationship was found with Smad-interacting-protein1 (SIP1), another transcription factor inducing epithelium-to-mesenchyme transition (EMT). Promoter-reporter assays indicated Cx43 repression at the promoter level by ectopically expressed Snail1. To establish whether the Cx43 down-regulation depends on endogenous Snail1, MES-1 cells, differentiated derivatives of P19 EC, were stably transfected by an siRNA construct silencing Snail1 expression. This resulted in a mesenchyme-to-epithelium transition, which was accompanied by increased levels of Cx43 mRNA and protein and enhanced metabolic and electrical coupling. We conclude that Snail1-mediated EMT results in a Cx43 repression.
authors.affiliation: Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands.
authors.forename: Teun P
authors.initials: TP
authors.lastname: de Boer
authors.forename: Toon A B
authors.initials: TA
authors.lastname: van Veen
authors.forename: Marti F A
authors.initials: MF
authors.lastname: Bierhuizen
authors.forename: Bart
authors.initials: B
authors.lastname: Kok
authors.forename: Martin B
authors.initials: MB
authors.lastname: Rook
authors.forename: Kristel J M
authors.initials: KJ
authors.lastname: Boonen
authors.forename: Marc A
authors.initials: MA
authors.lastname: Vos
authors.forename: Pieter A
authors.initials: PA
authors.lastname: Doevendans
authors.forename: Jacques M T
authors.initials: JM
authors.lastname: de Bakker
authors.forename: Marcel A G
authors.initials: MA
authors.lastname: van der Heyden
mesh_terms: D000818:Animals; D018236:Carcinoma, Embryonal; D045744:Cell Line, Tumor; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D020868:Gene Silencing; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D018031:Connexin 43; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C000604429:Snai1 protein, mouse; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors