title: Isl2b regulates anterior second heart field development in zebrafish.
abstract: After initial formation, the heart tube grows by addition of second heart field progenitor cells to its poles. The transcription factor Isl1 is expressed in the entire second heart field in mouse, and Isl1-deficient mouse embryos show defects in arterial and venous pole development. The expression of Isl1 is conserved in zebrafish cardiac progenitors; however, Isl1 is required for cardiomyocyte differentiation only at the venous pole. Here we show that Isl1 homologues are expressed in specific patterns in the developing zebrafish heart and play distinct roles during cardiac morphogenesis. In zebrafish, isl2a mutants show defects in cardiac looping, whereas isl2b is required for arterial pole development. Moreover, Isl2b controls the expression of key cardiac transcription factors including mef2ca, mef2cb, hand2 and tbx20. The specific roles of individual Islet family members in the development of distinct regions of the zebrafish heart renders this system particularly well-suited for dissecting Islet-dependent gene regulatory networks controlling the behavior and function of second heart field progenitors in distinct steps of cardiac development.
authors.affiliation: Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
authors.forename: Hagen R
authors.initials: HR
authors.lastname: Witzel
authors.affiliation: Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
authors.forename: Sirisha
authors.initials: S
authors.lastname: Cheedipudi
authors.affiliation: Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
authors.forename: Rui
authors.initials: R
authors.lastname: Gao
authors.affiliation: Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
authors.forename: Didier Y R
authors.initials: DY
authors.lastname: Stainier
authors.affiliation: Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.|Medical Faculty, University of Frankfurt, 60590 Frankfurt am Main, Germany.
authors.forename: Gergana D
authors.initials: GD
authors.lastname: Dobreva
mesh_terms: D000818:Animals; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000254:growth & development*; D060850:LIM-Homeodomain Proteins / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D015027:Zebrafish
chemical_list: D060850:LIM-Homeodomain Proteins; D014157:Transcription Factors; C558563:isl2b protein, zebrafish