title: Msx1CreERT2 knock-In allele: A useful tool to target embryonic and adult cardiac valves.
abstract: Heart valve development begins with the endothelial-to-mesenchymal transition (EMT) of endocardial cells. Although lineage studies have demonstrated contributions from cardiac neural crest and epicardium to semilunar and atrioventricular (AV) valve formation, respectively, most valve mesenchyme derives from the endocardial EMT. Specific Cre mouse lines for fate-mapping analyses of valve endocardial cells are limited. Msx1 displayed expression in AV canal endocardium and cushion mesenchyme between E9.5 and E11.5, when EMT is underway. Additionally, previous studies have demonstrated that deletion of Msx1 and its paralog Msx2 results in hypoplastic AV cushions and impaired endocardial signaling. A knock-in tamoxifen-inducible Cre line was recently generated (Msx1CreERT2) and characterized during embryonic development and after birth, and was shown to recapitulate the endogenous Msx1 expression pattern. Here, we further analyze this knock-in allele and track the Msx1-expressing cells and their descendants during cardiac development with a particular focus on their contribution to the valves and their precursors. Thus, Msx1CreERT2 mice represent a useful model for lineage tracing and conditional gene manipulation of endocardial and mesenchymal cushion cells essential to understand mechanisms of valve development and remodeling.
authors.affiliation: Aix Marseille Université, GMGF, UMR_S910, Faculté de Médecine, 27 Bd Jean Moulin, 13385, Marseille, France.|Inserm, U910, Faculté de Médecine, 27 Bd Jean Moulin, 13005, Marseille, France.|Intercellular Signalling in Cardiovascular Development & Disease Laboratory, Centro Nacional De Investigaciones Cardiovasculares (CNIC), Madrid, Spain.
authors.forename: Tania
authors.initials: T
authors.lastname: Papoutsi
authors.affiliation: Aix Marseille Université, GMGF, UMR_S910, Faculté de Médecine, 27 Bd Jean Moulin, 13385, Marseille, France.|Inserm, U910, Faculté de Médecine, 27 Bd Jean Moulin, 13005, Marseille, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Odelin
authors.affiliation: Aix Marseille Université, GMGF, UMR_S910, Faculté de Médecine, 27 Bd Jean Moulin, 13385, Marseille, France.|Inserm, U910, Faculté de Médecine, 27 Bd Jean Moulin, 13005, Marseille, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Moore-Morris
authors.affiliation: Aix Marseille Université, GMGF, UMR_S910, Faculté de Médecine, 27 Bd Jean Moulin, 13385, Marseille, France.|Inserm, U910, Faculté de Médecine, 27 Bd Jean Moulin, 13005, Marseille, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Pucéat
authors.affiliation: Intercellular Signalling in Cardiovascular Development & Disease Laboratory, Centro Nacional De Investigaciones Cardiovasculares (CNIC), Madrid, Spain.
authors.forename: José Luis
authors.initials: JL
authors.lastname: de la Pompa
authors.affiliation: Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Robert
authors.affiliation: Aix Marseille Université, GMGF, UMR_S910, Faculté de Médecine, 27 Bd Jean Moulin, 13385, Marseille, France.|Inserm, U910, Faculté de Médecine, 27 Bd Jean Moulin, 13005, Marseille, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Zaffran
mesh_terms: D000483:Alleles; D000818:Animals; D004699:Endocardium / Q000201:enzymology / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D055879:Gene Knock-In Techniques; D006351:Heart Valves / Q000196:embryology* / Q000378:metabolism*; D019426:Integrases / Q000235:genetics* / Q000378:metabolism; D051957:MSX1 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D038081:Organogenesis / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics* / Q000378:metabolism
chemical_list: D051957:MSX1 Transcription Factor; D011960:Receptors, Estrogen; C045073:Cre recombinase; D019426:Integrases
keywords: Msx; heart; lineage tracing; mouse development; tamoxifen-inducible Cre; valvulogenesis