title: Generation of a Cre knock-in into the Myocardin locus to mark early cardiac and smooth muscle cell lineages.
abstract: The molecular events that control cell fate determination in cardiac and smooth muscle lineages remain elusive. Myocardin is an important transcription cofactor that regulates cell proliferation, differentiation, and development of the cardiovascular system. Here, we describe the construction and analysis of a dual Cre and enhanced green fluorescent protein (EGFP) knock-in mouse line in the Myocardin locus (Myocd(KI)). We report that the Myocd(KI) allele expresses the Cre enzyme and the EGFP in a manner that recapitulates endogenous Myocardin expression patterns. We show that Myocardin expression marks the earliest cardiac and smooth muscle lineages. Furthermore, this genetic model allows for the identification of a cardiac cell population, which maintains both Myocardin and Isl-1 expression, in E7.75-E8.0 embryos, highlighting the contribution and merging of the first and second heart fields during cardiogenesis. Therefore, the Myocd(KI) allele is a unique tool for studying cardiovascular development and lineage-specific gene manipulation.
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ramón A
authors.initials: RA
authors.lastname: Espinoza-Lewis
authors.forename: Da-Zhi
authors.initials: DZ
authors.lastname: Wang
mesh_terms: D000818:Animals; D019070:Cell Lineage; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D055879:Gene Knock-In Techniques; D056426:Genetic Loci; D019426:Integrases / Q000235:genetics*; D060850:LIM-Homeodomain Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D032383:Myocytes, Cardiac / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D009928:Organ Specificity; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D000099251:Myocardin
chemical_list: D019426:Integrases; D060850:LIM-Homeodomain Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000099251:Myocardin; C063843:insulin gene enhancer binding protein Isl-1; C045073:Cre recombinase
keywords: Cre; EGFP; heart; myocardin; smooth muscle