title: Pericardin, a Drosophila type IV collagen-like protein is involved in the morphogenesis and maintenance of the heart epithelium during dorsal ectoderm closure.
abstract: The steps that lead to the formation of a single primitive heart tube are highly conserved in vertebrate and invertebrate embryos. Concerted migration of the two lateral cardiogenic regions of the mesoderm and endoderm (or ectoderm in invertebrates) is required for their fusion at the midline of the embryo. Morphogenetic signals are involved in this process and the extracellular matrix has been proposed to serve as a link between the two layers of cells. Pericardin (Prc), a novel Drosophila extracellular matrix protein is a good candidate to participate in heart tube formation. The protein has the hallmarks of a type IV collagen alpha-chain and is mainly expressed in the pericardial cells at the onset of dorsal closure. As dorsal closure progresses, Pericardin expression becomes concentrated at the basal surface of the cardioblasts and around the pericardial cells, in close proximity to the dorsal ectoderm. Pericardin is absent from the lumen of the dorsal vessel. Genetic evidence suggests that Prc promotes the proper migration and alignment of heart cells. Df(3)vin6 embryos, as well as embryos in which prc has been silenced via RNAi, exhibit similar and significant defects in the formation of the heart epithelium. In these embryos, the heart epithelium appears disorganized during its migration to the dorsal midline. By the end of embryonic development, cardial and pericardial cells are misaligned such that small clusters of both cell types appear in the heart; these clusters of cells are associated with holes in the walls of the heart. A prc transgene can partially rescue each of these phenotypes, suggesting that prc regulates these events. Our results support, for the first time, the function of a collagen-like protein in the coordinated migration of dorsal ectoderm and heart cells.
authors.affiliation: Laboratoire de Génétique et Physiologie du Développement, UMR 6545 CNRS-Université, IBDM-CNRS-INSERM-Université de la Méditerranée, Campus de Luminy, Case 907, 13288 Marseille Cedex 09, France.
authors.forename: Aymeric
authors.initials: A
authors.lastname: Chartier
authors.forename: Stéphane
authors.initials: S
authors.lastname: Zaffran
authors.forename: Martine
authors.initials: M
authors.lastname: Astier
authors.forename: Michel
authors.initials: M
authors.lastname: Sémériva
authors.forename: Danielle
authors.initials: D
authors.lastname: Gratecos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D002465:Cell Movement; D024141:Collagen Type IV / Q000235:genetics* / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004475:Ectoderm; D004625:Embryo, Nonmammalian; D004848:Epithelium / Q000196:embryology; D005109:Extracellular Matrix / Q000276:immunology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D009154:Mutation; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000235:genetics; D012330:RNA, Double-Stranded; D020449:Repetitive Sequences, Amino Acid
chemical_list: D000911:Antibodies, Monoclonal; D024141:Collagen Type IV; D029721:Drosophila Proteins; D012330:RNA, Double-Stranded; C110854:puc protein, Drosophila; D010749:Phosphoprotein Phosphatases