title: Immunolocalization of skeletal matrix proteins in tissue and mineral of the coral Stylophora pistillata.
abstract: The precipitation and assembly of calcium carbonate skeletons by stony corals is a precisely controlled process regulated by the secretion of an ECM. Recently, it has been reported that the proteome of the skeletal organic matrix (SOM) contains a group of coral acid-rich proteins as well as an assemblage of adhesion and structural proteins, which together, create a framework for the precipitation of aragonite. To date, we are aware of no report that has investigated the localization of individual SOM proteins in the skeleton. In particular, no data are available on the ultrastructural mapping of these proteins in the calcification site or the skeleton. This information is crucial to assessing the role of these proteins in biomineralization. Immunological techniques represent a valuable approach to localize a single component within a calcified skeleton. By using immunogold labeling and immunohistochemical assays, here we show the spatial arrangement of key matrix proteins in tissue and skeleton of the common zooxanthellate coral, Stylophora pistillata. To our knowledge, our results reveal for the first time that, at the nanoscale, skeletal proteins are embedded within the aragonite crystals in a highly ordered arrangement consistent with a diel calcification pattern. In the tissue, these proteins are not restricted to the calcifying epithelium, suggesting that they also play other roles in the coral's metabolic pathways.
authors.affiliation: Environmental Biophysics and Molecular Ecology Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901;
authors.forename: Tali
authors.initials: T
authors.lastname: Mass
authors.affiliation: Environmental Biophysics and Molecular Ecology Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901;
authors.forename: Jeana L
authors.initials: JL
authors.lastname: Drake
authors.affiliation: Department of Environmental Science and Policy, George Mason University, Fairfax, VA 22030;
authors.forename: Esther C
authors.initials: EC
authors.lastname: Peters
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7; and.
authors.forename: Wenge
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Environmental Biophysics and Molecular Ecology Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854 falko@marine.rutgers.edu.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Falkowski
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D037421:Anthozoa / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D000906:Antibodies / Q000494:pharmacology; D015820:Cadherins / Q000737:chemistry / Q000378:metabolism; D002119:Calcium Carbonate / Q000737:chemistry* / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000737:chemistry / Q000378:metabolism; D003460:Crystallization; D016326:Extracellular Matrix Proteins / Q000737:chemistry* / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D016253:Microscopy, Immunoelectron / Q000379:methods; D008903:Minerals / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D049329:Nanostructures
chemical_list: D000199:Actins; D000906:Antibodies; D015820:Cadherins; D016326:Extracellular Matrix Proteins; D008903:Minerals; D002256:Carbonic Anhydrases; D002119:Calcium Carbonate
keywords: CARPs; actin; cadherins; carbonic anhydrase