title: Isl1 expression at the venous pole identifies a novel role for the second heart field in cardiac development.
abstract: The right ventricle and outflow tract of the developing heart are derived from mesodermal progenitor cells from the second heart field (SHF). SHF cells have been characterized by expression of the transcription factor Islet-1 (Isl1). Although Isl1 expression has also been reported in the venous pole, the specific contribution of the SHF to this part of the heart is unknown. Here we show that Isl1 is strongly expressed in the dorsal mesenchymal protrusion (DMP), a non-endocardially-derived mesenchymal structure involved in atrioventricular septation. We further demonstrate that abnormal development of the SHF-derived DMP is associated with the pathogenesis of atrioventricular septal defects. These results identify a novel role for the SHF.
authors.affiliation: Department of Cell Biology and Anatomy, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Snarr
authors.forename: Jessica L
authors.initials: JL
authors.lastname: O'Neal
authors.forename: Mastan R
authors.initials: MR
authors.lastname: Chintalapudi
authors.forename: Elaine E
authors.initials: EE
authors.lastname: Wirrig
authors.forename: Aimee L
authors.initials: AL
authors.lastname: Phelps
authors.forename: Steven W
authors.initials: SW
authors.lastname: Kubalak
authors.forename: Andy
authors.initials: A
authors.lastname: Wessels
mesh_terms: D000818:Animals; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006321:Heart / Q000196:embryology* / Q000502:physiology*; D006330:Heart Defects, Congenital / Q000235:genetics / Q000503:physiopathology*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D060850:LIM-Homeodomain Proteins; D008648:Mesoderm / Q000196:embryology / Q000502:physiology; D051379:Mice; D008817:Mice, Mutant Strains; D011247:Pregnancy; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; C484469:Nkx2-5 protein, mouse; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1