title: A Cranial Mesoderm Origin for Esophagus Striated Muscles.
abstract: The esophagus links the oral cavity to the stomach and facilitates the transfer of bolus. Using genetic tracing and mouse mutants, we demonstrate that esophagus striated muscles (ESMs) are not derived from somites but are of cranial origin. Tbx1 and Isl1 act as key regulators of ESMs, which we now identify as a third derivative of cardiopharyngeal mesoderm that contributes to second heart field derivatives and head muscles. Isl1-derived ESM progenitors colonize the mouse esophagus in an anterior-posterior direction but are absent in the developing chick esophagus, thus providing evolutionary insight into the lack of ESMs in avians. Strikingly, different from other myogenic regions, in which embryonic myogenesis establishes a scaffold for fetal fiber formation, ESMs are established directly by fetal myofibers. We propose that ESM progenitors use smooth muscle as a scaffold, thereby bypassing the embryonic program. These findings have important implications in understanding esophageal dysfunctions, including dysphagia, and congenital disorders, such as DiGeorge syndrome.
authors.affiliation: Department of Developmental & Stem Cell Biology, Institut Pasteur, Stem Cells & Development, CNRS URA 2578, 25 Rue du Dr. Roux, 75015 Paris, France.
authors.forename: Swetha
authors.initials: S
authors.lastname: Gopalakrishnan
authors.affiliation: Department of Developmental & Stem Cell Biology, Institut Pasteur, Stem Cells & Development, CNRS URA 2578, 25 Rue du Dr. Roux, 75015 Paris, France.
authors.forename: Glenda
authors.initials: G
authors.lastname: Comai
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, GKVK P.O., Bellary Road, Bangalore 560065, India.
authors.forename: Ramkumar
authors.initials: R
authors.lastname: Sambasivan
authors.affiliation: Aix Marseille Université, CNRS, IBDM UMR 7288, 13288 Marseille, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Francou
authors.affiliation: Aix Marseille Université, CNRS, IBDM UMR 7288, 13288 Marseille, France.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Kelly
authors.affiliation: Department of Developmental & Stem Cell Biology, Institut Pasteur, Stem Cells & Development, CNRS URA 2578, 25 Rue du Dr. Roux, 75015 Paris, France. Electronic address: shahragim.tajbakhsh@pasteur.fr.
authors.forename: Shahragim
authors.initials: S
authors.lastname: Tajbakhsh
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation; D002478:Cells, Cultured; D002645:Chickens; D004622:Embryo, Mammalian / Q000166:cytology* / Q000378:metabolism; D004947:Esophagus / Q000196:embryology*; D005260:Female; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology; D007124:Immunoenzyme Techniques; D060850:LIM-Homeodomain Proteins / Q000502:physiology; D008297:Male; D008648:Mesoderm / Q000196:embryology*; D051379:Mice; D018345:Mice, Knockout; D024510:Muscle Development / Q000502:physiology*; D054792:Muscle, Striated / Q000196:embryology*; D009432:Neural Crest / Q000166:cytology; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012886:Skull / Q000196:embryology*; D019170:Somites / Q000166:cytology; D020825:T-Box Domain Proteins / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology
chemical_list: D060850:LIM-Homeodomain Proteins; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; C491573:Tbx1 protein, mouse; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1; C068686:Pax3 protein, mouse