Generation of a C re knock‐in into the M yocardin locus to mark early cardiac and smooth muscle cell lineages

• Published in: Genesis (New York, N.Y. : 2000) N.Y. : 2000), 2014-10, Vol.52 (10), p.879-887
• Main Authors: Espinoza‐Lewis, Ramón A, Wang, Da‐Zhi
• Format: Article
• Language: English
• ISSN: 1526-954X; 1526-968X
• DOI: 10.1002/dvg.22819

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. genesis 52:879–887, 2014. © 2014 Wiley Periodicals, Inc.