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Joswig JS, Wirth C, Schuman MC, Kattge J, Reu B, Wright IJ, Sippel SD, Rüger N, Richter R, Schaepman ME, van Bodegom PM, Cornelissen JHC, Díaz S, Hattingh WN, Kramer K, Lens F, Niinemets Ü, Reich PB, Reichstein M, Römermann C, Schrodt F, Anand M, Bahn M, Byun C, Campetella G, Cerabolini BEL, Craine JM, Gonzalez-Melo A, Gutiérrez AG, He T, Higuchi P, Jactel H, Kraft NJB, Minden V, Onipchenko V, Peñuelas J, Pillar VD, Sosinski Ê, Soudzilovskaia NA, Weiher E, Mahecha MD. Climatic and soil factors explain the two-dimensional spectrum of global plant trait variation. Nat Ecol Evol 2022; 6:36-50. [PMID: 34949824 PMCID: PMC8752441 DOI: 10.1038/s41559-021-01616-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 11/10/2021] [Indexed: 11/09/2022]
Abstract
Plant functional traits can predict community assembly and ecosystem functioning and are thus widely used in global models of vegetation dynamics and land-climate feedbacks. Still, we lack a global understanding of how land and climate affect plant traits. A previous global analysis of six traits observed two main axes of variation: (1) size variation at the organ and plant level and (2) leaf economics balancing leaf persistence against plant growth potential. The orthogonality of these two axes suggests they are differently influenced by environmental drivers. We find that these axes persist in a global dataset of 17 traits across more than 20,000 species. We find a dominant joint effect of climate and soil on trait variation. Additional independent climate effects are also observed across most traits, whereas independent soil effects are almost exclusively observed for economics traits. Variation in size traits correlates well with a latitudinal gradient related to water or energy limitation. In contrast, variation in economics traits is better explained by interactions of climate with soil fertility. These findings have the potential to improve our understanding of biodiversity patterns and our predictions of climate change impacts on biogeochemical cycles.
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Affiliation(s)
- Julia S. Joswig
- grid.419500.90000 0004 0491 7318Max-Planck-Institute for Biogeochemistry, Jena, Germany ,grid.7400.30000 0004 1937 0650Remote Sensing Laboratories, Department of Geography, University of Zurich, Zurich, Switzerland
| | - Christian Wirth
- grid.419500.90000 0004 0491 7318Max-Planck-Institute for Biogeochemistry, Jena, Germany ,grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany ,grid.9647.c0000 0004 7669 9786Institute of Systematic Botany and Functional Biodiversity, University of Leipzig, Leipzig, Germany
| | - Meredith C. Schuman
- grid.7400.30000 0004 1937 0650Remote Sensing Laboratories, Department of Geography, University of Zurich, Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Jens Kattge
- grid.419500.90000 0004 0491 7318Max-Planck-Institute for Biogeochemistry, Jena, Germany ,grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
| | - Björn Reu
- grid.411595.d0000 0001 2105 7207Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Ian J. Wright
- grid.1004.50000 0001 2158 5405Department of Biological Sciences, Macquarie University, Sydney, New South Wales Australia
| | - Sebastian D. Sippel
- grid.5801.c0000 0001 2156 2780Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland ,grid.454322.60000 0004 4910 9859Norwegian Institute of Bioeconomy Research, Oslo, Norway
| | - Nadja Rüger
- grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany ,grid.9647.c0000 0004 7669 9786Department of Economics, University of Leipzig, Leipzig, Germany ,grid.438006.90000 0001 2296 9689Smithsonian Tropical Research Institute, Ancón, Panama
| | - Ronny Richter
- grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany ,grid.9647.c0000 0004 7669 9786Institute of Systematic Botany and Functional Biodiversity, University of Leipzig, Leipzig, Germany ,grid.9647.c0000 0004 7669 9786Geoinformatics and Remote Sensing, Institute for Geography, University of Leipzig, Leipzig, Germany
| | - Michael E. Schaepman
- grid.7400.30000 0004 1937 0650Remote Sensing Laboratories, Department of Geography, University of Zurich, Zurich, Switzerland
| | - Peter M. van Bodegom
- grid.5132.50000 0001 2312 1970Environmental Biology Department, Institute of Environmental Sciences, CML, Leiden University, Leiden, the Netherlands
| | - J. H. C. Cornelissen
- grid.12380.380000 0004 1754 9227Systems Ecology, Department of Ecological Science, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Sandra Díaz
- grid.10692.3c0000 0001 0115 2557Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET and FCEFyN, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | - Koen Kramer
- grid.4818.50000 0001 0791 5666Chairgroup Forest Ecology and Forest Management, Wageningen University, Wageningen, the Netherlands ,Land Life Company, Amsterdam, the Netherlands
| | - Frederic Lens
- grid.425948.60000 0001 2159 802XResearch Group Functional Traits, Naturalis Biodiversity Center, Leiden, the Netherlands ,grid.5132.50000 0001 2312 1970Plant Sciences, Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
| | - Ülo Niinemets
- grid.16697.3f0000 0001 0671 1127Estonian University of Life Sciences, Tartu, Estonia
| | - Peter B. Reich
- grid.17635.360000000419368657Department of Forest Resources, University of Minnesota, St Paul, MN USA ,grid.1029.a0000 0000 9939 5719Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales Australia ,grid.214458.e0000000086837370Institute for Global Change Biology and School for Environment and Sustainability, University of Michigan, Ann Arbor, MI USA
| | - Markus Reichstein
- grid.419500.90000 0004 0491 7318Max-Planck-Institute for Biogeochemistry, Jena, Germany ,grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
| | - Christine Römermann
- grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany ,grid.9613.d0000 0001 1939 2794Department of Plant Biodiversity, Institute of Ecology and Evolution, Friedrich-Schiller University, Jena, Germany
| | - Franziska Schrodt
- grid.4563.40000 0004 1936 8868School of Geography, University of Nottingham, Nottingham, UK
| | - Madhur Anand
- grid.34429.380000 0004 1936 8198School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Michael Bahn
- grid.5771.40000 0001 2151 8122Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Chaeho Byun
- grid.252211.70000 0001 2299 2686Department of Biological Sciences and Biotechnology, Andong National University, Andong, Korea
| | - Giandiego Campetella
- grid.5602.10000 0000 9745 6549Plant Diversity and Ecosystems Management Unit, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Bruno E. L. Cerabolini
- grid.18147.3b0000000121724807Department of Biotechnologies and Life Sciences (DBSV), University of Insubria, Varese, Italy
| | | | - Andres Gonzalez-Melo
- grid.412191.e0000 0001 2205 5940Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
| | - Alvaro G. Gutiérrez
- grid.443909.30000 0004 0385 4466Departamento de Ciencias Ambientales y Recursos Naturales Renovables, Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago, Chile
| | - Tianhua He
- grid.1032.00000 0004 0375 4078School of Molecular and Life Sciences, Curtin University, Perth, Western Australia Australia ,grid.1025.60000 0004 0436 6763College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia Australia
| | - Pedro Higuchi
- grid.412287.a0000 0001 2150 7271Department of Forestry, Universidade do Estado de Santa, Catarina, Lages, Brazil
| | - Hervé Jactel
- grid.508391.60000 0004 0622 9359INRAE University Bordeaux, BIOGECO, Cestas, France
| | - Nathan J. B. Kraft
- grid.19006.3e0000 0000 9632 6718Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA USA
| | - Vanessa Minden
- grid.8767.e0000 0001 2290 8069Department of Biology, Vrije Universiteit Brussel, Brussels, Belgium ,grid.5560.60000 0001 1009 3608Landscape Ecology Group, Institute of Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
| | - Vladimir Onipchenko
- grid.14476.300000 0001 2342 9668Department of Ecology and Plant Geography, Moscow State Lomonosov University, Moscow, Russia
| | - Josep Peñuelas
- grid.4711.30000 0001 2183 4846CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Spain ,grid.452388.00000 0001 0722 403XCREAF, Cerdanyola del Vallés, Spain
| | - Valério D. Pillar
- grid.8532.c0000 0001 2200 7498Department of Ecology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Ênio Sosinski
- grid.460200.00000 0004 0541 873XEmbrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil
| | - Nadejda A. Soudzilovskaia
- grid.12155.320000 0001 0604 5662Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium ,grid.5132.50000 0001 2312 1970Institute of Environmental Sciences, Leiden University, Leiden, the Netherlands
| | - Evan Weiher
- grid.267460.10000 0001 2227 2494Department of Biology, University of Wisconsin, Eau Claire, WI USA
| | - Miguel D. Mahecha
- grid.9647.c0000 0004 7669 9786German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany ,grid.9647.c0000 0004 7669 9786Remote Sensing Centre for Earth System Research, University of Leipzig, Leipzig, Germany ,grid.7492.80000 0004 0492 3830Helmholtz Centre for Environmental Research, Leipzig, Germany
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Su S, Munganga BP, Tian C, Li J, Yu F, Li H, Wang M, He X, Tang Y. Comparative Analysis of the Intermolt and Postmolt Hepatopancreas Transcriptomes Provides Insight into the Mechanisms of Procambarus clarkii Molting Process. Life (Basel) 2021; 11:480. [PMID: 34070595 PMCID: PMC8228513 DOI: 10.3390/life11060480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 11/17/2022] Open
Abstract
In the present study, we used RNA-Seq to investigate the expression changes in the transcriptomes of two molting stages (postmolt (M) and intermolt (NM)) of the red swamp crayfish and identified differentially expressed genes. The transcriptomes of the two molting stages were de novo assembled into 139,100 unigenes with a mean length of 675.59 bp. The results were searched against the NCBI, NR, KEGG, Swissprot, and KOG databases, to annotate gene descriptions, associate them with gene ontology terms, and assign them to pathways. Furthermore, using the DESeq R package, differentially expressed genes were evaluated. The analysis revealed that 2347 genes were significantly (p > 0.05) differentially expressed in the two molting stages. Several genes and other factors involved in several molecular events critical for the molting process, such as energy requirements, hormonal regulation, immune response, and exoskeleton formation were identified and evaluated by correlation and KEGG analysis. The expression profiles of transcripts detected via RNA-Seq were validated by real-time PCR assay of eight genes. The information presented here provides a transient view of the hepatopancreas transcripts available in the postmolt and intermolt stage of crayfish, hormonal regulation, immune response, and skeletal-related activities during the postmolt stage and the intermolt stage.
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Affiliation(s)
- Shengyan Su
- Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China;
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Brian Pelekelo Munganga
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Can Tian
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Jianlin Li
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Fan Yu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Hongxia Li
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Meiyao Wang
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Xinjin He
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
| | - Yongkai Tang
- Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China;
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; (B.P.M.); (C.T.); (J.L.); (F.Y.); (H.L.); (M.W.); (X.H.)
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Novel Insights into Regulation of Human Teeth Biomineralization: Deciphering the Role of Post-Translational Modifications in a Tooth Protein Extract. Int J Mol Sci 2019; 20:ijms20164035. [PMID: 31430851 PMCID: PMC6720696 DOI: 10.3390/ijms20164035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/16/2019] [Accepted: 08/17/2019] [Indexed: 12/11/2022] Open
Abstract
The importance of whole protein extracts from different types of human teeth in modulating the process of teeth biomineralization is reported. There are two crucial features in protein molecules that result in efficient teeth biomineralization. Firstly, the unique secondary structure characteristics within these proteins i.e. the exclusive presence of a large amount of intrinsic disorder and secondly, the presence of post-translational modifications (PTM) like phosphorylation and glycosylation within these protein molecules. The present study accesses the structural implications of PTMs in the tooth proteins through scanning electron microscopy and transmission electron microscopy. The deglycosylated/dephosphorylated protein extracts failed to form higher-order mineralization assemblies. Furthermore, through nanoparticle tracking analysis (NTA) we have shown that dephosphorylation and deglycosylation significantly impact the biomineralization abilities of the protein extract and resulted in smaller sized clusters. Hence, we propose these post-translational modifications are indispensable for the process of teeth biomineralization. In addition to basic science, this study would be worth consideration while designing of biomimetics architecture for an efficient peptide-based teeth remineralization strategy.
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Ashikov A, Abu Bakar N, Wen XY, Niemeijer M, Rodrigues Pinto Osorio G, Brand-Arzamendi K, Hasadsri L, Hansikova H, Raymond K, Vicogne D, Ondruskova N, Simon MEH, Pfundt R, Timal S, Beumers R, Biot C, Smeets R, Kersten M, Huijben K, Linders PTA, van den Bogaart G, van Hijum SAFT, Rodenburg R, van den Heuvel LP, van Spronsen F, Honzik T, Foulquier F, van Scherpenzeel M, Lefeber DJ, Mirjam W, Han B, Helen M, Helen M, Peter VH, Jiddeke VDK, Diego M, Lars M, Katja BH, Jozef H, Majid A, Kevin C, Johann TWN. Integrating glycomics and genomics uncovers SLC10A7 as essential factor for bone mineralization by regulating post-Golgi protein transport and glycosylation. Hum Mol Genet 2018; 27:3029-3045. [DOI: 10.1093/hmg/ddy213] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/29/2018] [Indexed: 01/13/2023] Open
Affiliation(s)
- Angel Ashikov
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Nurulamin Abu Bakar
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Xiao-Yan Wen
- Zebrafish Centre for Advanced Drug Discovery & Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St Michael’s Hospital, Toronto, ON, Canada
- Department of Medicine, Physiology & Institute of Medical Science, Faculty of Medicine, University of Toronto, ON, Canada
| | - Marco Niemeijer
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Glentino Rodrigues Pinto Osorio
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Koroboshka Brand-Arzamendi
- Zebrafish Centre for Advanced Drug Discovery & Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St Michael’s Hospital, Toronto, ON, Canada
- Department of Medicine, Physiology & Institute of Medical Science, Faculty of Medicine, University of Toronto, ON, Canada
| | - Linda Hasadsri
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Hana Hansikova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Kimiyo Raymond
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Dorothée Vicogne
- CNRS-UMR 8576, Structural and Functional Glycobiology Unit, FRABIO, University of Lille, 59655 Villeneuve d’Ascq, France
| | - Nina Ondruskova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Marleen E H Simon
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Sharita Timal
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Roel Beumers
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Christophe Biot
- CNRS-UMR 8576, Structural and Functional Glycobiology Unit, FRABIO, University of Lille, 59655 Villeneuve d’Ascq, France
| | - Roel Smeets
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Marjan Kersten
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Karin Huijben
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Peter T A Linders
- Department of Tumor Immunology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Sacha A F T van Hijum
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- NIZO, 6710 BA Ede, The Netherlands
| | - Richard Rodenburg
- Radboud Center for Mitochondrial Disorders, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | | | - Francjan van Spronsen
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - Tomas Honzik
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Francois Foulquier
- CNRS-UMR 8576, Structural and Functional Glycobiology Unit, FRABIO, University of Lille, 59655 Villeneuve d’Ascq, France
| | - Monique van Scherpenzeel
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Dirk J Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Wamelink Mirjam
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Brunner Han
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Mundy Helen
- Centre for Inherited Metabolic Disease, Evelina Children's Hospital, Guys and St Thomas NHS Foundation Trust, London SE1 7EH, UK
| | - Michelakakis Helen
- Department of Enzymology and Cellular Function, Institute of Child Health, Athens, Greece
| | - van Hasselt Peter
- Department of Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands
| | - van de Kamp Jiddeke
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Martinelli Diego
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Research Hospital, Rome, Italy
| | - Morkrid Lars
- Department of Medical Biochemistry, Oslo University Hospital, and Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | | | | | - Alfadhel Majid
- King Abdullah International Medical Research Centre, King Saud bin Abdul Aziz University for Health Sciences, Division of Genetics, Department of Pediatrics, King Abdullah Specialized Children Hospital, King Abdul Aziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Carpenter Kevin
- NSW Biochemical Genetics Service, The Children's Hospital at Westmead, Disciplines of Genetic Medicine & Child and Adolescent Health, The University of Sydney, NSW 2145, Australia
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Mitani K, Haruyama N, Hatakeyama J, Igarashi K. Amelogenin splice isoforms stimulate chondrogenic differentiation of ATDC5 cells. Oral Dis 2012; 19:169-79. [DOI: 10.1111/j.1601-0825.2012.01967.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 06/03/2012] [Accepted: 06/15/2012] [Indexed: 12/15/2022]
Affiliation(s)
- K Mitani
- Department of Oral Dysfunction Science; Tohoku University Graduate School of Dentistry; Sendai Japan
| | - N Haruyama
- Department of Oral Dysfunction Science; Tohoku University Graduate School of Dentistry; Sendai Japan
- Global Centre of Excellence Program; International Research Centre for Molecular Science in Tooth and Bone Diseases; Tokyo Medical and Dental University; Tokyo Japan
| | - J Hatakeyama
- Functional Structure Section; Fukuoka Dental College; Fukuoka Japan
| | - K Igarashi
- Department of Oral Dysfunction Science; Tohoku University Graduate School of Dentistry; Sendai Japan
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Abstract
Enamel is a hard nanocomposite bioceramic with significant resilience that protects the mammalian tooth from external physical and chemical damages. The remarkable mechanical properties of enamel are associated with its hierarchical structural organization and its thorough connection with underlying dentin. This dynamic mineralizing system offers scientists a wealth of information that allows the study of basic principels of organic matrix-mediated biomineralization and can potentially be utilized in the fields of material science and engineering for development and design of biomimetic materials. This chapter will provide a brief overview of enamel hierarchical structure and properties and the process and stages of amelogenesis. Particular emphasis is given to current knowledge of extracellular matrix protein and proteinases, and the structural chemistry of the matrix components and their putative functions. The chapter will conclude by discussing the potential of enamel for regrowth.
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Affiliation(s)
- Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA.
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7
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Kuballa AV, Elizur A. Differential expression profiling of components associated with exoskeletal hardening in crustaceans. BMC Genomics 2008; 9:575. [PMID: 19040762 PMCID: PMC2612702 DOI: 10.1186/1471-2164-9-575] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 12/01/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Exoskeletal hardening in crustaceans can be attributed to mineralization and sclerotization of the organic matrix. Glycoproteins have been implicated in the calcification process of many matrices. Sclerotization, on the other hand, is catalysed by phenoloxidases, which also play a role in melanization and the immunological response in arthropods. Custom cDNA microarrays from Portunus pelagicus were used to identify genes possibly associated with the activation pathways involved in these processes. RESULTS Two genes potentially involved in the recognition of glycosylation, the C-type lectin receptor and the mannose-binding protein, were found to display molt cycle-related differential expression profiles. C-type lectin receptor up-regulation was found to coincide with periods associated with new uncalcified cuticle formation, while the up-regulation of mannose-binding protein occurred only in the post-molt stage, during which calcification takes place, implicating both in the regulation of calcification. Genes presumed to be involved in the phenoloxidase activation pathway that facilitates sclerotization also displayed molt cycle-related differential expression profiles. Members of the serine protease superfamily, trypsin-like and chymotrypsin-like, were up-regulated in the intermolt stage when compared to post-molt, while trypsin-like was also up-regulated in pre-molt compared to ecdysis. Additionally, up-regulation in pre- and intermolt stages was observed by transcripts encoding other phenoloxidase activators including the putative antibacterial protein carcinin-like, and clotting protein precursor-like. Furthermore, hemocyanin, itself with phenoloxidase activity, displayed an identical expression pattern to that of the phenoloxidase activators, i.e. up-regulation in pre- and intermolt. CONCLUSION Cuticle hardening in crustaceans is a complex process that is precisely timed to occur in the post-molt stage of the molt cycle. We have identified differential expression patterns of several genes that are believed to be involved in biomineralization and sclerotization and propose possible regulatory mechanisms for these processes based on their expression profiles, such as the potential involvement of C-type lectin receptors and mannose binding protein in the regulation of calcification.
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Affiliation(s)
- Anna V Kuballa
- Department of Primary Industries and Fisheries, Animal Science, Bribie Island, Queensland 4507, Australia.
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8
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Kobayashi K, Yamakoshi Y, Hu JCC, Gomi K, Arai T, Fukae M, Krebsbach PH, Simmer JP. Splicing determines the glycosylation state of ameloblastin. J Dent Res 2007; 86:962-7. [PMID: 17890672 DOI: 10.1177/154405910708601009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In developing porcine enamel, the space between enamel rods selectively binds lectins and ameloblastin (Ambn) N-terminal antibodies. We tested the hypothesis that ameloblastin N-terminal cleavage products are glycosylated. Assorted Ambn cleavage products showed positive lectin staining by peanut agglutinin (PNA), Maclura pomifera agglutinin (MPA), and Limulus polyphemus agglutinin (LPA), suggesting the presence of an O-linked glycosylation containing galactose (Gal), N-acetylgalactosamine (GalNAc), and sialic acid. Edman sequencing of the lectin-positive bands gave the Ambn N-terminal sequence: VPAFPRQPGTXGVASLXLE. The blank cycles for Pro(11) and Ser(17) confirmed that these residues are hydroxylated and phosphorylated, respectively. The O-glycosylation site was determined by Edman sequencing of pronase-digested Ambn, which gave HPPPLPXQPS, indicating that Ser(86) is the site of the O-linked glycosylation. This modification is within the 15-amino-acid segment (73-YEYSLPVHPPPLPSQ-87) deleted by splicing in the mRNA encoding the 380-amino-acid Ambn isoform. We conclude that only the N-terminal Ambn products derived from the 395-Ambn isoform are glycosylated.
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Affiliation(s)
- K Kobayashi
- Department of Biologic and Materials Sciences, Dental Research Lab, 1210 Eisenhower Place, Ann Arbor, MI 48108, USA
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9
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Iwata T, Yamakoshi Y, Hu JCC, Ishikawa I, Bartlett JD, Krebsbach PH, Simmer JP. Processing of ameloblastin by MMP-20. J Dent Res 2007; 86:153-7. [PMID: 17251515 DOI: 10.1177/154405910708600209] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ameloblastin (AMBN) cleavage products are the most abundant non-amelogenin proteins in the enamel matrix of developing teeth. AMBN N-terminal cleavage products accumulate in the sheath space between enamel rods, while AMBN C-terminal products localize within rods. We tested the hypothesis that MMP-20 is the protease that cleaves AMBN. Glycosylated recombinant porcine AMBN (rpAMBN) was expressed in human kidney 293F cells, and recombinant porcine enamelysin (rpMMP-20) was expressed in bacteria. The purified proteins were incubated together at an enzyme:substrate ratio of 1:100. N-terminal sequencing of AMBN digestion products determined that rpMMP-20 cleaved rpAMBN after Pro(2), Gln(130), Gln(139), Arg(170), and Ala(222). This shows that MMP-20 generates the 23-kDa AMBN starting at Tyr(223), as well as the 17-kDa (Val(1)-Arg(170)) and 15-kDa (Val(1)-Gln(130)) AMBN cleavage products that concentrate in the sheath space during the secretory stage. We conclude that MMP-20 processes ameloblastin in vitro and in vivo.
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Affiliation(s)
- T Iwata
- Department of Biologic and Materials Sciences, Dental Research Lab, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI 48108, USA
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10
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Ravindranath RMH, Basilrose RM. Localization of sulfated sialic acids in the dentinal tubules during tooth formation in mice. Acta Histochem 2005; 107:43-56. [PMID: 15866285 DOI: 10.1016/j.acthis.2004.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Revised: 10/25/2004] [Accepted: 11/11/2004] [Indexed: 11/27/2022]
Abstract
Lectin-like properties of the major enamel protein amelogenin suggest that it binds to glycoconjugates in dentinal tubules released at the dentin-enamel junction (DEJ) during enamel formation. Therefore, a detailed mapping of glycosylation in dentinal tubules during tooth formation was undertaken using histochemistry and lectin-binding assays. The tubular content exhibited sialidase-susceptible gamma-metachromasia with Toluidine Blue (pH 2.5) and staining with Alcian Blue (pH 1.0). The presence of sulfate groups was confirmed by benzidine reactions (Bracco-Curti's and tetrazonium assays). Alpha2,3-, alpha2,6- and alpha2,8-sialidases entirely abolished staining with the benzidine reactions. The presence of sialic acids in dentinal tubules was confirmed with the Bial's reaction and sialidase-susceptible binding of Limax flavus lectin suggesting that sialic acids are the major sulfated sugars in the glycoconjguates. Immunostaining with the monoclonal antibody 5-D-4 before and after treatment with chondroitin-4- and chondroitin-6-sulfatase confirmed the presence of keratan sulfate (KS), a sialylated proteoglycan, in dentinal tubules. We suggest that sulfated sialic acids are part of the KSs. The sulfated glycoconjugates are also found in dentin and the DEJ but not in predentin suggesting that amelogenin binds to the sialoconjugate during enamel formation.
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Affiliation(s)
- Rajeswari M H Ravindranath
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA.
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11
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Dillaman R, Hequembourg S, Gay M. Early pattern of calcification in the dorsal carapace of the blue crab,Callinectes sapidus. J Morphol 2005; 263:356-74. [PMID: 15688443 DOI: 10.1002/jmor.10311] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The pattern of calcium carbonate deposition was observed in the dorsal carapace of premolt (D2-D3) and early postmolt (0-48 h) blue crabs, Callinectes sapidus, using scanning (SEM) and transmission (TEM) electron microscopy. Samples of dorsal carapace for SEM were quick-frozen in liquid nitrogen, subsequently lyophilized, and viewed using secondary and backscattered electrons as well as X-ray maps of calcium. Pieces of lyophilized cuticle were also embedded in epoxy resin and subsequently sectioned and viewed with TEM and SEM. Fresh pieces of dorsal carapace for TEM were also fixed in 2.5% glutaraldehyde in phosphate buffer followed by postfixation in 1% OsO4 in cacodylate buffer. Calcium concentrations were determined using atomic absorption spectrophotometry and quantitative X-ray microanalysis. Calcium accumulation began in the cuticle at 3 h postmolt at the epicuticle/exocuticle boundary and at the distal and proximal margins of the interprismatic septa (IPS). The bidirectional calcification of the IPS continued until the two fronts met at 5-8 h postmolt. The roughly hexagonal walls of the IPS formed a honeycomb-like structure that resulted in a rigid cuticle. The walls of the canal containing sensory neurons also calcified at 3 h, thereby imparting rigidity to the structure and additional strength to the cuticle. Examination of thin sections of lyophilized cuticle and fixed cuticle revealed that the first mineral deposited is more soluble than calcite and is probably amorphous calcium carbonate. The amorphous calcium carbonate is transformed to calcite along a front that follows the original deposition and is probably controlled by a specialized matrix within the IPS. Since amorphous calcium carbonate is isotropic, it would also make the mineral in the exocuticle stronger by an equal distribution of mechanical stress.
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Affiliation(s)
- Richard Dillaman
- Department of Biological Sciences, University of North Carolina at Wilmington, Wilmington, North Carolina 28403, USA.
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12
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Ravindranath RMH, Basilrose RM, Ravindranath NH, Vaitheesvaran B. Amelogenin interacts with cytokeratin-5 in ameloblasts during enamel growth. J Biol Chem 2003; 278:20293-302. [PMID: 12657653 DOI: 10.1074/jbc.m211184200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The enamel protein amelogenin binds to GlcNAc (Ravindranath, R. M. H., Moradian-Oldak, R., and Fincham, A.G. (1999) J. Biol. Chem. 274, 2464-2471) and to the GlcNAc-mimicking peptide (GMp) (Ravindranath, R. M. H., Tam, W., Nguyen, P., and Fincham, A. G. (2000) J. Biol. Chem. 275, 39654-39661). The GMp motif in the N-terminal region of the cytokeratin 14 of ameloblasts binds to trityrosyl motif peptide (ATMP) of amelogenin (Ravindranath, R. M. H., Tam, W., Bringas, P., Santos, V., and Fincham, A. G. (2001) J. Biol. Chem. 276, 36586 - 36597). K14 (Type I) pairs with K5 (Type II) in basal epithelial cells; GlcNAc-acylated K5 is identified in ameloblasts. Dosimetric analysis showed the binding affinity of amelogenin to K5 and to GlcNAc-acylated-positive control, ovalbumin. The specific binding of [3H]ATMP with K5 or ovalbumin was confirmed by Scatchard analysis. [3H]ATMP failed to bind to K5 after removal of GlcNAc. Blocking K5 with ATMP abrogates the K5-amelogenin interaction. K5 failed to bind to ATMP when the third proline was substituted with threonine, as in some cases of human X-linked amelogenesis imperfecta or when tyrosyl residues were substituted with phenylalanine. Confocal laser scan microscopic observations on ameloblasts during postnatal (PN) growth of the teeth showed that the K5-amelogenin complex migrated from the cytoplasm to the periphery (on PN day 1) and accumulated at the apical region on day 3. Secretion of amelogenin commences from day 1. K5, similar to K14, may play a role of chaperone during secretion of amelogenin. Upon secretion of amelogenin, K5 pairs with K14. Pairing of K5 and K14 commences on day 3 and ends on day 9. The pairing of K5 and K14 marks the end of secretion of amelogenin.
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Affiliation(s)
- Rajeswari M H Ravindranath
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles 90033-1004, USA.
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13
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Compère P, Jaspar-Versali MF, Goffinet G. Glycoproteins from the cuticle of the Atlantic shore crab Carcinus maenas: I. Electrophoresis and Western-blot analysis by use of lectins. THE BIOLOGICAL BULLETIN 2002; 202:61-73. [PMID: 11842016 DOI: 10.2307/1543223] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The protein and glycoprotein content of four different neutral or acidic solvent extracts (0.5 M KCl, 10% EDTA, 0.1 N HCl, or 2% acetic acid) from the mineralized exoskeleton of a decapod crustacean, the Atlantic shore crab Carcinus maenas, were characterized by quantitative analysis of proteins, SDS-PAGE analysis, and probing with lectins on blots. The lectins used were Conconavalin A, Jacalin, soybean agglutinin, Maackia amurensis agglutinin II, and Sambucus nigra agglutinin. The results show that many proteins can be obtained from the crab cuticle without strong denaturants in the extraction medium. Many of the extracted cuticle proteins appeared to be glycosylated, bearing O-linked oligosaccharides and N-linked mannose-rich glycans. N-acetyl-galactosamine and N-acetylneuraminic acids were revealed, for the first time, as terminal residues on N-linked mannose-rich structures of crab cuticle glycoproteins. Sialylated glycoproteins might thus be involved in organic-mineral interactions in the calcified crab exoskeleton. The amount and variety of glycoproteins extracted with the acidic solvents are obviously different from those extracted with neutral solvents. HCl proved to be the best of the tested extraction solvents and a valuable alternative to EDTA.
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Affiliation(s)
- Philippe Compère
- Laboratoire de Biologie générale et de Morphologie ultrastructurale, Université de Liège, Institut de Zoologie (I1), 22, quai Ed. Van Beneden, B-4020 Liège, Belgium.
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14
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Ravindranath RM, Tam WY, Bringas P, Santos V, Fincham AG. Amelogenin-cytokeratin 14 interaction in ameloblasts during enamel formation. J Biol Chem 2001; 276:36586-97. [PMID: 11425863 DOI: 10.1074/jbc.m104656200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The enamel protein amelogenin binds to the GlcNAc-mimicking peptide (GMp) (Ravindranath, R. M. H., Tam, W., Nguyen, P., and Fincham, A. G. (2000) J. Biol. Chem. 275, 39654-39661). The GMp motif is found in the N-terminal region of CK14, a differentiation marker for ameloblasts. The binding affinity of CK14 and amelogenin was confirmed by dosimetric binding of CK14 to recombinant amelogenin (rM179), and to the tyrosine-rich amelogenin polypeptide. The specific binding site for CK14 was identified in the amelogenin trityrosyl motif peptide (ATMP) of tyrosine-rich amelogenin polypeptide and specific interaction between CK14 and [(3)H]ATMP was confirmed by Scatchard analysis. Blocking rM179 with GlcNAc, GMp, or CK14 with ATMP abrogates the CK14-amelogenin interaction. CK14 failed to bind to ATMP when the third proline was substituted with threonine, as in some cases of human X-linked amelogenesis imperfecta or when tyrosyl residues were substituted with phenylalanine. Morphometry of developing teeth distinguished three phases of enamel formation; growth initiation phase (days 0-1), prolific growth phase (days 1-7), and growth cessation phase (post-day 7). Confocal microscopy revealed co-assembly of CK14/amelogenin in the perinuclear region of ameloblasts on day 0, migration of the co-assembled CK14/amelogenin to the apical region of the ameloblasts from day 1, reaching a peak on days 3-5, and a collapse of the co-assembly. Autoradiography with [(3)H]ATMP and [(3)H]GMp corroborated the dissociation of the co-assembly at the ameloblast Tomes' process. It is proposed that CK14 play a chaperon role for nascent amelogenin polypeptide during amelogenesis.
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Affiliation(s)
- R M Ravindranath
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, California 90033, USA.
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15
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Yamakoshi Y, Pinheiro FH, Tanabe T, Fukae M, Shimizu M. Sites of asparagine-linked oligosaccharides in porcine 32 kDa enamelin. Connect Tissue Res 2001; 39:39-46; discussion 63-7. [PMID: 11062987 DOI: 10.3109/03008209809023910] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The 32 kDa enamelin protein isolated from developing porcine enamel was previously shown to contain eight different asparagine-linked oligosaccharides. However, only three consensus attachment sites were evident in this protein. In this study, glycopeptides containing all three potential glycosylation sites (72-Asn, 79-Asn and 91-Asn) were purified from 32 kDa enamelin. The oligosaccharides were isolated from each glycopeptide following digestion with N-oligosaccharide glycopeptidase, labeled with 2-aminopyridine at the reducing ends, and then characterized by reverse phase HPLC. All three potential sites were found to be glycosylated heterogeneously (i.e., five biantennary complexes at 72-Asn, two biantennary complexes at 79-Asn, three triantennary complexes at 91-Asn), accounting for all eight oligosaccharides characterized previously. These results indicate that 32 kDa enamelin has a complex pattern of asparagine-linked glycosylation localized within a small region (20 residues) of the protein. The functional significance of this glycosylation remains to be established.
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Affiliation(s)
- Y Yamakoshi
- Department of Biochemistry, School of Dental Medicine, Tsurumi University, Yokohama, Japan
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16
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Smith CE, Chen WY. Degradative changes in whole enamel homogenates incubated in vitro in the presence of low calcium ion concentrations. Connect Tissue Res 2001; 39:75-87; discussion 141-9. [PMID: 11062990 DOI: 10.3109/03008209809023914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The purpose of this study was to investigate overall degradative changes occurring to enamel matrix proteins in small, freeze-dried pieces of rat incisor enamel homogenized and incubated directly for 0-48 hours in a synthetic enamel fluid solution (165 mM total ionic strength with 0.153 mM calcium chloride) versus other samples homogenized and incubated for the same time intervals in distilled water. The results indicated that many alterations in the apparent molecular weights of enamel matrix proteins took place under both conditions although the rates for many degradative changes over a 48 hour period were often slower in distilled water than in synthetic enamel fluid. Freeze-dried enamel samples homogenized and incubated in 165 mM Tris-HCl buffer at pH 8.0 showed changes comparable to those seen with distilled water. This suggested that differences observed between samples incubated in enamel fluid versus distilled water were unrelated to pH or ionic strength of the solutions and may be the result of a requirement by some enamel proteinases for small amounts of free calcium ions in incubation media. Of interest were findings that some enamel matrix proteins, especially those in strips taken from the first half of the secretory stage of amelogenesis, were degraded much faster in distilled water than in synthetic enamel fluid. The reasons for this effect are unclear although, in this case, calcium ions could be inhibitory to hydrolysis of certain matrix proteins by the enamel proteinases.
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Affiliation(s)
- C E Smith
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.
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17
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Kirkham J, Brookes SJ, Shore RC, Bonass WA, Smith DA, Wallwork ML, Robinson C. Atomic force microscopy studies of crystal surface topology during enamel development. Connect Tissue Res 2001; 38:91-100; discussion 139-45. [PMID: 11063018 DOI: 10.3109/03008209809017025] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
During the secretory stage of enamel development, the hydroxyapatite crystals appear as thin ribbons which grow substantially in width and thickness during the later maturation stage. In this study, the atomic force microscope (AFM) was used to investigate developmentally-related changes in deproteinized enamel crystal surface topography in normal animals and in those receiving daily doses of fluoride. The AFM revealed previously undescribed surfaces features, some of which may represent growth sites or different crystalline phases. Secretory stage crystals had greater surface rugosity and were more irregular, with spherical sub-structures of 20-30 nm diameter arranged along the "c"-axis. Maturation stage crystals were smoother and larger but revealed both subnanometer steps and lateral grooves running parallel to the "c"-axis. Crystals from fluorotic tissue showed similar features but were more irregular with a higher degree of surface roughness, suggesting abnormal growth. The AFM may prove an important adjunct in determination of the mechanisms controlling crystal size and morphology in skeletal tissues.
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Affiliation(s)
- J Kirkham
- Division of Oral Biology, Leeds Dental Institute, UK.
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18
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Ravindranath RM, Tam WY, Nguyen P, Fincham AG. The enamel protein amelogenin binds to the N-acetyl-D-glucosamine-mimicking peptide motif of cytokeratins. J Biol Chem 2000; 275:39654-61. [PMID: 10980199 DOI: 10.1074/jbc.m006471200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Amelogenins bind to GlcNAc of the dentine-enamel matrix proteins (Ravindranath, R. M. H., Moradian-Oldak, J., Fincham, A. G. (1999) J. Biol. Chem. 274, 2464-2471). The hypothesis that amelogenins may interact with the peptides that mimic GlcNAc is tested. GlcNAc-mimicking peptide (SFGSGFGGGY) but not its variants with single amino acid substitution at serine, tyrosine, or phenylalanine residues inhibited hemagglutination of amelogenins and the terminal tyrosine-rich amelogenin polypeptide (TRAP). The binding affinity of SFGSGFGGGY to amelogenins was confirmed by dosimetric binding of amelogenins or TRAP with [(3)H]peptide, specific binding in varying concentrations of the peptide, Scatchard plot analysis, and competitive inhibition with the unlabeled peptide. The ability of the peptide or GlcNAc to stoichiometrically inhibit TRAP binding of [(14)C]GlcNAc or [(3)H]peptide indicated that both the peptide and GlcNAc compete for a single binding site. Using different fragments of amelogenins, we have identified the peptide-binding motif in amelogenin to be the same as the GlcNAc-binding "amelogenin trityrosyl motif peptide." The GlcNAc-mimicking peptide failed to bind to the amelogenin trityrosyl motif peptide when the tyrosyl residues were substituted with phenylalanine or when the third proline was replaced with threonine, as in some cases of human X-linked amelogenesis imperfecta. This study documents that molecular mimicry may play a role in stability and organization of amelogenin during amelogenesis.
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Affiliation(s)
- R M Ravindranath
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, California 90033, USA.
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19
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Kirkham J, Zhang J, Brookes SJ, Shore RC, Wood SR, Smith DA, Wallwork ML, Ryu OH, Robinson C. Evidence for charge domains on developing enamel crystal surfaces. J Dent Res 2000; 79:1943-7. [PMID: 11201043 DOI: 10.1177/00220345000790120401] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The control of hydroxyapatite crystal initiation and growth during enamel development is thought to be mediated via the proteins of the extracellular matrix. However, the precise nature of these matrix-mineral interactions remains obscure. The aim of the present study was to use a combination of atomic and chemical force microscopy to characterize developing enamel crystal surfaces and to determine their relationship with endogenous enamel matrix protein (amelogenin). The results show regular and discrete domains of various charges or charge densities on the surfaces of hydroxyapatite crystals derived from the maturation stage of enamel development. Binding of amelogenin to individual crystals at physiological pH was seen to be coincident with positively charged surface domains. These domains may therefore provide an instructional template for matrix-mineral interactions. Alternatively, the alternating array of charge on the crystal surfaces may reflect the original relationship with, and influence of, matrix interaction with the crystal surfaces during crystal growth.
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Affiliation(s)
- J Kirkham
- Division of Oral Biology, Leeds Dental Institute, The University of Leeds, UK.
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20
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Fincham AG, Moradian-Oldak J, Simmer JP. The structural biology of the developing dental enamel matrix. J Struct Biol 1999; 126:270-99. [PMID: 10441532 DOI: 10.1006/jsbi.1999.4130] [Citation(s) in RCA: 474] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The biomineralization of the dental enamel matrix with a carbonated hydroxyapatite mineral generates one of the most remarkable examples of a vertebrate mineralized tissue. Recent advances in the molecular biology of ameloblast gene products have now revealed the primary structures of the principal proteins involved in this extracellular mineralizing system, amelogenins, tuftelins, ameloblastins, enamelins, and proteinases, but details of their secondary, tertiary, and quaternary structures, their interactions with other matrix and or cell surface proteins, and their functional role in dental enamel matrix mineralization are still largely unknown. This paper reviews our current knowledge of these molecules, the probable molecular structure of the enamel matrix, and the functional role of these extracellular matrix proteins. Recent studies on the major structural role played by the amelogenin proteins are discussed, and some new data on synthetic amelogenin matrices are reviewed.
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Affiliation(s)
- A G Fincham
- Center for Craniofacial Molecular Biology, School of Dentistry, Los Angeles, California 90089, USA
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21
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Ravindranath RM, Moradian-Oldak J, Fincham AG. Tyrosyl motif in amelogenins binds N-acetyl-D-glucosamine. J Biol Chem 1999; 274:2464-71. [PMID: 9891017 DOI: 10.1074/jbc.274.4.2464] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ameloblasts secrete amelogenins on the pre-existing enamel matrix glycoproteins at the dentine-enamel junction. The hypothesis that amelogenins may interact with enamel matrix glycoproteins is tested by hemagglutination of purified, native (porcine) and recombinant murine amelogenins (rM179 and rM166) and hemagglutination inhibition with sugars. Amelogenin agglutination of murine erythrocytes was specifically inhibited by N-acetylglucosamine (GlcNAc), chitobiose, and chitotetraose and by ovalbumin with terminal GlcNAc. The GlcNAc affinity was confirmed by dosimetric binding of rM179 with [14C]GlcNAc, specific binding in relation to varying concentrations of GlcNAc, Scatchard plot analysis and competitive inhibition with cold GlcNAc. The hemagglutination activity and [14C]GlcNAc affinity were retained by the NH2-terminal tyrosine-rich amelogenin peptide (TRAP) but not by the leucine-rich amelogenin peptide, LRAP (a polypeptide sharing 33 amino acid residues of TRAP), or by the C-terminal 13 residue polypeptide of amelogenin (rM179). Since TRAP but not the 33-residue sequence of the TRAP shared by LRAP bound to [14C]GlcNAc, we inferred that the GlcNAc binding motif was located in the 13-residue tyrosyl C-terminal domain of TRAP (PYPSYGYEPMGGW), which was absent from LRAP. [14C]GlcNAc did indeed bind to this "amelogenin tyrosyl motif peptide" but not when the tyrosyl residues were substituted with phenylalanine or when the third proline was replaced by threonine. Significantly, this latter modification mimics a point mutation identified in a case of human X-linked amelogenesis imperfecta. The amelogenin tyrosyl motif peptide sequence showed a similarity to the secondary GlcNAc-binding site of wheat germ agglutinin.
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Affiliation(s)
- R M Ravindranath
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, California 90033, USA
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22
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Cuticular proteins from the blue crab alter in vitro calcium carbonate mineralization. Comp Biochem Physiol B Biochem Mol Biol 1998. [DOI: 10.1016/s0305-0491(98)10117-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
The present paper evaluates the enamel growth tracks as tools in the chronological mapping of dental development, with special reference to hominids. Dental enamel consists of tightly packed hydroxyapatite crystals organized by differential orientation into a pattern of prisms and interprisms. The crystal organization is probably under the influence of both cellular and physico-chemical factors. The structure of mature enamel testifies to events that took place during enamel formation. The prisms are the fossilized tracks traced out by ameloblasts. The tangential diameter of ameloblasts and the central distance of prisms increase from the enamel-dentine junction to the enamel surface. Available evidence suggests that prism cross-striations are light microscopic expressions of prism varicosities and/or compositional variations, that these are due to a rhythm in enamel formation, and that this rhythm is diurnal. In human enamel the mean daily rate of enamel production is about 3.5 micron, but increases from inner to outer enamel and decreases from incisal/cuspal to cervical enamel. Conclusive evidence has shown that Retzius lines are incremental lines. Evenly spaced Retzius lines probably represent a 6-11 day rhythm in enamel formation, while other Retzius lines may be due to various types of stress. The geometry of the enamel growth tracks and their chronological significance are valuable tools in chronological mapping of dental development and for understanding temporal and spatial patterns in tooth morphogenesis. The taxonomic significance of prism packing patterns, prism decussation and enamel thickness should be clarified through further systematic descriptive research.
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Affiliation(s)
- S Risnes
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, N-0316, Norway.
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Smith CE. Cellular and chemical events during enamel maturation. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1998; 9:128-61. [PMID: 9603233 DOI: 10.1177/10454411980090020101] [Citation(s) in RCA: 497] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This review focuses on the process of enamel maturation, a series of events associated with slow, progressive growth in the width and thickness of apatitic crystals. This developmental step causes gradual physical hardening and transformation of soft, newly formed enamel into one of the most durable mineralized tissues produced biologically. Enamel is the secretory product of specialized epithelial cells, the ameloblasts, which make this covering on the crowns of teeth in two steps. First, they roughly "map out" the location and limits (overall thickness) of the entire extracellular layer as a protein-rich, acellular, and avascular matrix filled with thin, ribbon-like crystals of carbonated hydroxyapatite. These initial crystals are organized spatially into rod and interrod territories as they form, and rod crystals are lengthened by Tomes' processes in tandem with appositional movement of ameloblasts away from the dentin surface. Once the full thickness of enamel has been formed, ameloblasts initiate a series of repetitive morphological changes at the enamel surface in which tight junctions and deep membrane infoldings periodically appear (ruffle-ended), then disappear for short intervals (smooth-ended), from the apical ends of the cells. As this happens, the enamel covered by these cells changes rhythmically in net pH from mildly acidic (ruffle-ended) to near-physiologic (smooth-ended) as mineral crystals slowly expand into the "spaces" (volume) formerly occupied by matrix proteins and water. Matrix proteins are processed and degraded by proteinases throughout amelogenesis, but they undergo more rapid destruction once ameloblast modulation begins. Ruffle-ended ameloblasts appear to function primarily as a regulatory and transport epithelium for controlling the movement of calcium and other ions such as bicarbonate into enamel to maintain buffering capacity and driving forces optimized for surface crystal growth. The reason ruffle-ended ameloblasts become smooth-ended periodically is unknown, although this event seems to be crucial for sustaining long-term crystal growth.
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Affiliation(s)
- C E Smith
- Faculty of Dentistry, and Department of Anatomy & Cell Biology, McGill University, Montreal, Quebec, Canada
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Hu CC, Fukae M, Uchida T, Qian Q, Zhang CH, Ryu OH, Tanabe T, Yamakoshi Y, Murakami C, Dohi N, Shimizu M, Simmer JP. Cloning and characterization of porcine enamelin mRNAs. J Dent Res 1997; 76:1720-9. [PMID: 9372788 DOI: 10.1177/00220345970760110201] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Dental enamel forms by matrix-mediated biomineralization. The components of the developing enamel matrix are generally specific for that matrix. The primary structures of three enamel proteins-amelogenin, tuftelin, and sheathlin (ameloblastin/amelin)-have been derived from cDNA sequences. Here we report the cloning and characterization of mRNA encoding a fourth enamel protein: enamelin. The longest porcine enamelin cDNA clone has 3907 nucleotides, exclusive of the poly(A) tail. The primary structure of the secreted protein is 1104 amino acids in length. Without post-translational modifications, the secreted protein has an isotope-averaged molecular mass of 124.3 kDa and an isoelectric point of 6.5. Polymerase chain-reaction phenotyping of enamelin cDNA suggests that porcine enamelin transcripts are not alternatively spliced and use a single polyadenylation/cleavage site. Immunohistochemical and Western blot analyses with an affinity-purified antipeptide antibody specific for the enamelin carboxyl terminus demonstrate that enamelin is synthesized and secreted by secretory-phase ameloblasts. The parent protein is a 186-kDa glycoprotein that concentrates along the secretory face of the ameloblast Tomes' process. Intact enamelin and proteolytic cleavage products containing its carboxyl terminus are limited to the most superficial layer of the developing enamel matrix, while other enamelin cleavage products are observed in deeper enamel.
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Affiliation(s)
- C C Hu
- University of Texas Health Science Center at San Antonio, School of Dentistry, Department of Pediatric Dentistry 78284-7888, USA
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Hu CC, Fukae M, Uchida T, Qian Q, Zhang CH, Ryu OH, Tanabe T, Yamakoshi Y, Murakami C, Dohi N, Shimizu M, Simmer JP. Sheathlin: cloning, cDNA/polypeptide sequences, and immunolocalization of porcine enamel sheath proteins. J Dent Res 1997; 76:648-57. [PMID: 9062558 DOI: 10.1177/00220345970760020501] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Sheath proteins designate low-molecular-weight non-amelogenin enamel polypeptides and their parent protein, which concentrate in the sheath space separating rod and inter-rod enamel (Uchida et al., 1995). Two porcine sheath proteins, with apparent molecular weights of 13 and 15 kDa, are characterized by protein sequencing. The primary structures of these polypeptides match a portion of the derived amino acid sequences of clones isolated from a porcine enamel organ epithelia-specific cDNA library. Sheath protein RNA messages differ by the inclusion or deletion of a 45-nucleotide segment and by the use of three alternative polyadenylation/cleavage sites. The secreted proteins are 395 and 380 residues in length, with molecular masses of 42,358 and 40,279 Daltons and calculated isoelectric points of 6.3 and 6.7, respectively. Polyclonal antibodies were raised against a synthetic peptide having the sheathlin-specific sequence EHETQQYEYSGGC. Immunohistochemistry with this antibody demonstrates that the protein encoded by the sheathlin cDNA is preferentially localized in the sheath space. We propose that the porcine sheath proteins and their proteolytic cleavage products be designated "sheathlin".
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Affiliation(s)
- C C Hu
- University of Texas Health Science Center at San Antonio, School of Dentistry, Department of Pediatric Dentistry 78284-7888, USA
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Nanci A, Hashimoto J, Zalzal S, Smith CE. Transient accumulation of proteins at interrod and rod enamel growth sites. Adv Dent Res 1996; 10:135-49. [PMID: 9206330 DOI: 10.1177/08959374960100020501] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Conceptually, there should be a brief interval in time when newly secreted proteins "pile up" at secretory sites just outside the membrane of ameloblasts. Indeed, previous cytochemical studies have suggested that glycosylated and/or sulfated glycoproteins accumulate at enamel growth sites. Colloidal gold lectin cytochemistry and immunocytochemistry with antibodies to enamel proteins and phosphoserine, combined with cycloheximide and brefeldin A to inhibit protein synthesis and secretion, were applied to characterize the distribution of newly formed proteins at enamel interrod and rod growth sites. Although enamel growth sites show a "rarefied" appearance, the results indicate that one or more subclasses of enamel proteins accumulate near the cell surface at sites where elongation of enamel crystallites contributes to thickening of the enamel layer. These proteins are glycosylated and/or phosphorylated and, at least in the case of the glycosylated ones, are rapidly processed after they are released extracellularly. In contrast, immunolabeling for amelogenins is generally weaker near the cell surface and more intense at a short distance away from the site where crystallites elongate. The data suggest that the enamel proteins accumulating at growth sites likely belong to the non-amelogenin category and play a transient role in promoting the lengthening of crystallites. It is concluded that areas near the ameloblast membrane where certain enamel proteins accumulate in fact constitute the equivalent of a mineralization front.
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Affiliation(s)
- A Nanci
- Department of Stomatology, Faculty of Dentistry, Université de Montréal, Québec, Canada
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28
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Hu CC, Bartlett JD, Zhang CH, Qian Q, Ryu OH, Simmer JP. Cloning, cDNA sequence, and alternative splicing of porcine amelogenin mRNAs. J Dent Res 1996; 75:1735-41. [PMID: 8955667 DOI: 10.1177/00220345960750100501] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In mammals, the organic matrix of developing enamel is dominated by amelogenins. To investigate the expression of proteins secreted into the developing enamel matrix, we have constructed a porcine enamel organ epithelia-specific cDNA library. The amelogenin fraction of the cDNA library was characterized by the cloning of amelogenin-specific polymerase chain-reaction (PCR) amplification products, 5' and 3' rapid amplification of cDNA ends (RACE), and by helper phage rescue of unamplified clones. Clones were characterized that encode porcine amelogenin isoforms 173, 157, 56, 41, and 40 amino acids in length. The structure of the porcine amelogenin gene differs from that of any of those yet described. There are two homologous but distinct exons 1, 2, and 7. One of the two exon 7s can vary in length depending upon the selection of either of two polyadenylation signal/cleavage sites. As a rule, a given exon 1 always pairs with the same exon 2 but can be associated with either exon 7. Despite significant sequence divergence within these exons, no differences are observed in exons 3, 5, and 6. We interpret these findings as evidence of a single amelogenin gene expressed from two promoters; however, the results do not exclude the existence of a second amelogenin gene. The variability generated through the use of alternate promoters and exon 7s primarily affects the non-coding regions of the message. A given amelogenin isoform expressed from the two promoters displays four amino acid differences within the signal peptide, while the secreted proteins are identical. Similarly, the alternative use of exon 7 does not alter the structure of the protein products. The pattern of RNA splicing of amelogenin pre-mRNAs is different for the transcripts expressed from the two promoters. The 173- and the 56-residue amelogenins can be expressed from either promoter, while the 157-residue amelogenin is generated by only one of the two promoters.
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Affiliation(s)
- C C Hu
- University of Texas School of Dentistry, Health Science Center at San Antonio, Department of Pediatric Dentistry 78284-7888, USA
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Abstract
BACKGROUND The synthesis, secretion, and fate of matrix proteins released by ameloblasts during enamel formation was studied in continuously erupting rat incisors. METHODS Computerized image processing was used to quantify silver grain distribution in radioautographs of sections prepared from rats injected with 3H-methionine, and this was correlated with fluorographs defining radiolabeling patterns of proteins in enamel organ cell and enamel homogenates prepared from freeze-dried teeth of rats injected with 35S-methionine and other radioactive amino acids and precursors such as sugar, sulfate, and phosphate. Some rats were also treated with brefeldin A to characterize newly formed proteins blocked from being secreted from ameloblasts. RESULTS The results indicate that ameloblasts rapidly synthesize and secrete (minutes) at least five primary enamel matrix proteins, including a 65 kDa sugar-containing sulfated enamel protein and four nonsulfated proteins with molecular weights near 31, 29, 27, and 23 kDa as estimated by SDS-PAGE. The 27 kDa protein appears to correspond to the primary amelogenin described in many species. The cells also appear to release at least one phosphoprotein with molecular weight near 27 kDa, which may be an amelogenin, and up to five cysteine-containing proteins with molecular weights near 94, 90, 72, 55, and 27 kDa. The proteins collectively are released at interrod and rod growth sites where they appear to remain close to their point of release from ameloblasts. The 65 kDa sulfated protein and 31 kDa nonsulfated protein are rapidly converted into lower molecular weight forms (hours), whereas nonsulfated proteins near 29, 27, and 23 kDa are more slowly transformed into fragments near 20, 18, and 10 kDa in molecular weight (days). These fragments do not accumulate but appear to be removed from the enamel layer as they are created. CONCLUSIONS Enamel proteins seen by Coomassie blue (or silver) staining of one-dimensional polyacrylamide gels, therefore, represent a composite image of newly secreted and derived forms of sulfated and nonsulfated proteins that sometimes have similar molecular weights.
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Affiliation(s)
- C E Smith
- Department of Anatomy, McGill University, Montreal, Quebec, Canada
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Sawada T, Nanci A. Spatial distribution of enamel proteins and fibronectin at early stages of rat incisor tooth formation. Arch Oral Biol 1995; 40:1029-38. [PMID: 8670021 DOI: 10.1016/0003-9969(95)00073-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Enamel proteins are secreted very early during amelogenesis, that is prior to mantle dentine formation, raising the possibility that they may participate in epithelial-mesenchymal interactions taking place during tooth development. These first enamel proteins associate with elements of the basement membrane interposed between the differentiating ameloblasts and odontoblasts. Fibronectin, a component of the basement membrane, is redistributed and accumulates along the apical portion of odontoblasts during their terminal differentiation. In order to determine whether any correlation exists between the redistribution of fibronectin and the secretion of the first enamel proteins, the spatial distribution of these two extracellular matrix proteins was examined during the presecretory stage of amelogenesis. Male Wistar rats were perfused with a formaldehyde-based fixative, and undemineralized and EDTA demineralized incisors were dehydrated in methanol and embedded in Lowicryl K4M resin. Ultrathin tissue sections were then processed for post-embedding, colloidal-gold immunocytochemistry with antibodies to enamel proteins, fibronectin or type III collagen. In the region of ameloblasts facing pulp, labelling for fibronectin was weak and mostly associated with the lamina fibroreticularis of the basement membrane separating differentiating ameloblasts and odontoblasts. As the mantle predentine formed the immunoreaction for fibronectin increased, particularly in the region of the basement membrane. Enamel proteins were also immunodetected in association with the lamina fibroreticularis and gradually accumulated as patches within mantle dentine and at its interface with ameloblasts. Von Korff collagen bundles, present between odontoblasts and in dentine, were immunolabelled for fibronectin and for type III collagen. Patches of granular material, immunoreactive for fibronectin and/or enamel proteins, were found along the odontoblastic processes and cell bodies. Although no evidence was obtained indicating a precise colocalization of fibronectin and enamel proteins, the results confirm that these two proteins can be found within similar extracellular compartments during mantle predentine-dentine formation. These data suggest that enamel proteins, by themselves or synergistically with other proteins, may play a part in the differentiation and/or formative events taking place at the ameloblast-odontoblast interface during the early stages of tooth development.
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Affiliation(s)
- T Sawada
- Department of Ultrastructural Science, Tokyo Dental College, Chiba, Japan
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31
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Chen WY, Nanci A, Smith CE. Immunoblotting studies on artifactual contamination of enamel homogenates by albumin and other proteins. Calcif Tissue Int 1995; 57:145-51. [PMID: 7584875 DOI: 10.1007/bf00298435] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The reason for the presence of albumin and other serum, cytoskeletal, cytosolic, and extracellular matrix proteins in enamel fractions was investigated by immunoblotting using homogenates prepared from freeze-dried and freshly dissected rat incisors, and antibodies capable of resolving at least 1 ng of the primary antigen. The data indicated that most of the 16 antibodies examined in this study reacted with antigens present only within "cell" homogenates (enamel organ cells + adhering labial connective tissue and blood vessels). One exception was rat serum albumin which was detected routinely in enamel homogenates prepared from freshly dissected, wiped incisors but rarely within enamel homogenates prepared from freeze-dried incisors. Another exception was calbindin-D 28 kDa which was consistently found within secretory stage enamel homogenates irrespective of preparative technique. A third exception was enamel proteins (amelogenins) which were enriched in secretory and early maturation stage enamel homogenates compared with cell homogenates and distributed as multiple molecular weight, antigenic bands in enamel homogenates (14-30 kDa), but mostly as a single antigenic band in cell homogenates (near 27 kDa). Overall, the results of this study suggest that developing rat incisor enamel naturally contains few exogenous proteins such as albumin. High concentrations of albumin (or other serum proteins) in crude homogenates, or purified fractions, derive mostly from blood and/or tissue fluids soaking into the enamel during sample preparation. This type of artifact can be avoided by using freeze-dried teeth for biochemical analyses.
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Affiliation(s)
- W Y Chen
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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32
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Smith CE, Chen WY, Issid M, Fazel A. Enamel matrix protein turnover during amelogenesis: basic biochemical properties of short-lived sulfated enamel proteins. Calcif Tissue Int 1995; 57:133-44. [PMID: 7584874 DOI: 10.1007/bf00298434] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The formation and turnover of sulfated enamel proteins was investigated by SDS-PAGE, fluorography, and TCA-precipitations using freeze-dried incisors of rats injected intravenously with 35S-sulfate (35SO4) and processed at various intervals from 1.6 minutes to 4 hours thereafter. Some rats were injected first with 35SO4 followed 5 minutes later by 0.3 mg of cycloheximide. This was done to terminate protein translation and allow events related to extracellular processing and degradation of the sulfated enamel proteins to be visualized more distinctly. Other rats were injected with cycloheximide followed at 0 minutes (simultaneous injection) to 30 minutes later by 35SO4. This was done to characterize the time required for proteins to travel from endoplasmic reticulum to Golgi apparatus, where they became sulfated. The results indicated that enamel organ cells (ameloblasts) rapidly incorporated 35SO4 into a major approximately 65 kDa protein that was secreted into the enamel within 6-7.5 minutes. This parent protein appeared to be processed extracellularly within 15 minutes into major approximately 49 kDa and approximately 25 kDa fragments which themselves had apparent half-lives of about 1 and 2 hours, respectively. There were also many minor sulfated fragments varying in molecular weight (Mr) from approximately 13-42 kDa, which appeared to originate from extracellular processing and/or degradation of the parent approximately 65 kDa sulfated enamel protein or its major approximately 49 kDa and approximately 25 kDa fragments. Experiments with glycosidases further suggested that the majority of sulfate groups were attached to sugars N-linked by asparagine to the core of the approximately 65 kDa sulfated enamel protein.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C E Smith
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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33
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Bronckers AL, Bervoets TJ, Lyaruu DM, Wöltgens JH. Degradation of hamster amelogenins during secretory stage enamel formation in organ culture. Matrix Biol 1995; 14:533-41. [PMID: 8535603 DOI: 10.1016/s0945-053x(05)80002-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Increasing amelogenin heterogeneity during pre-eruptive enamel formation has been explained by proteolytic cleavage of a parent amelogenin, differences in posttranslational modifications, translation of multiple alternative spliced mRNA transcripts or combinations of these possibilities. We investigated the possibility of proteolytic degradation of amelogenins during secretory amelogenesis by pulse-labelling amelogenins with [3H]proline followed by a pulse chase, all under organ culture conditions. The results indicate that during pulse chase, hamster molar tooth explants rapidly released substantial amounts of the radioactivity into the culture medium, as non-trichloroacetic-acid precipitable, noncollagenous 3H-activity at the expense of radioactivity associated with the proteins in the enamel space. Simultaneously, there was a continuous mineralization of the forming enamel in vitro as shown by an increase in total calcium content of the explants. Western blotting, microdissection studies and fluorography of radiolabelled matrix proteins after SDS-PAGE indicated that after an 8-h labelling, three radioactive amelogenin species could be extracted from forming enamel, one prominent species of molecular mass 26 kDa and two less prominent ones of 28 and 22 kDa. During pulse chase more amelogenin bands with lower molecular mass became apparent, a pattern similar to that observed in vivo. Examination of amelogenin blots with the glycan assay showed that none of the hamster amelogenins stained for carbohydrate. We conclude that changes in the amelogenin profiles during enamel development of cultured hamster explants are similar to those observed in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A L Bronckers
- Department of Oral Cell Biology, Academic Center for Dentistry Amsterdam, (ACTA), The Netherlands
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34
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Kumari SS, Skinner DM. Proteins of crustacean exoskeleton: III. Glycoproteins in the Bermuda land crabGecarcinus lateralis. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/jez.1402710602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
The structures of asparagine-linked oligosaccharides of porcine 32 kDa enamelin are reported. The oligosaccharides were released by N-oligosaccharide glycopeptidase digestion, and the reducing ends of the oligosaccharides were derivatized with a fluorescent reagent, 2-aminopyridine. The pyridylamino oligosaccharides were separated into eight kinds of oligosaccharides. The structures of these oligosaccharides were determined by a combination of a sequential exoglycosidase digestion and a two-dimensional sugar mapping technique. The oligosaccharides consisted of fucose, galactose, mannose, N-acetylglucosamine, and N-acetylneuraminic acid, and were classified into two groups according to their core-sugar chain structures; one was a biantennary-type and the other was a triantennary-type oligosaccharide. The variation of the oligosaccharides in each of these groups was caused by the differences in the number, the site, and the mode of linkage of N-acetylneuraminic acid to the core-sugar chains.
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Affiliation(s)
- Y Yamakoshi
- Department of Biochemistry, School of Dental Medicine, Tsurumi University, Yokohama, Japan
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36
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Simmer JP, Fincham AG. Molecular mechanisms of dental enamel formation. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1995; 6:84-108. [PMID: 7548623 DOI: 10.1177/10454411950060020701] [Citation(s) in RCA: 316] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Tooth enamel is a unique mineralized tissue in that it is acellular, is more highly mineralized, and is comprised of individual crystallites that are larger and more oriented than other mineralized tissues. Dental enamel forms by matrix-mediated biomineralization. Enamel crystallites precipitate from a supersaturated solution within a well-delineated biological compartment. Mature enamel crystallites are comprised of non-stoichiometric carbonated calcium hydroxyapatite. The earliest crystallites appear suddenly at the dentino-enamel junction (DEJ) as rapidly growing thin ribbons. The shape and growth patterns of these crystallites can be interpreted as evidence for a precursor phase of octacalcium phosphate (OCP). An OCP crystal displays on its (100) face a surface that may act as a template for hydroxyapatite (OHAp) precipitation. Octacalcium phosphate is less stable than hydroxyapatite and can hydrolyze to OHAp. During this process, one unit cell of octacalcium phosphate is converted into two unit cells of hydroxyapatite. During the precipitation of the mineral phase, the degree of saturation of the enamel fluid is regulated. Proteins in the enamel matrix may buffer calcium and hydrogen ion concentrations as a strategy to preclude the precipitation of competing calcium phosphate solid phases. Tuftelin is an acidic enamel protein that concentrates at the DEJ and may participate in the nucleation of enamel crystals. Other enamel proteins may regulate crystal habit by binding to specific faces of the mineral and inhibiting growth. Structural analyses of recombinant amelogenin are consistent with a functional role in establishing and maintaining the spacing between enamel crystallites.
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Affiliation(s)
- J P Simmer
- University of Texas School of Dentistry, Health Science Center at San Antonio, Department of Pediatric Dentistry 78284-7888, USA
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37
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Shafer TH, Roer RD, Midgette-Luther C, Brookins TA. Postecdysial cuticle alteration in the blue crab,Callinectes sapidus: Synchronous changes in glycoproteins and mineral nucleation. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/jez.1402710303] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bonucci E, Lozupone E, Silvestrini G, Favia A, Mocetti P. Morphological studies of hypomineralized enamel of rat pups on calcium-deficient diet, and of its changes after return to normal diet. Anat Rec (Hoboken) 1994; 239:379-95. [PMID: 7978362 DOI: 10.1002/ar.1092390405] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Micro-hardness investigations have shown that rat pups nursed by mothers on a low calcium diet and weaned with the maternal calcium-deficient diet develop hypomineralized enamel. The inorganic and organic components of this enamel, their relationships, and their changes after return to normal diet have been studied by light and electron microscopy. METHODS The maturation zone of incisor enamel has been studied in: (1) rats nursed for 20 days by mothers on a low calcium diet and weaned for 30 days with the same diet (E1 enamel); (2) rats that after the calcium-deficient diet were fed normal diet for 10 days (E2 enamel); and (3) rats nursed for 20 days by mothers on a normal diet and weaned for 30 days with a normal diet (controls). RESULTS The results showed that E1 enamel was hypomineralized, as noted by its Azure II-Methylene blue stainability in undecalcified sections, its light staining with the von Kossa method, and its ultrastructure. E1 crystallites, although present throughout the whole enamel, were thinner than those of E2 enamel, which were similar to those of controls. E1 interrod crystallites were thicker in the intermediate than in the dentinal zone and were thicker than rod crystallites. Organic matrix was present throughout the whole E1 enamel. Its organic components (crystal ghosts) had the same shape, arrangement, and organization as those of inorganic crystallites. Crystal ghosts were greatly reduced in E2 enamel and in controls. CONCLUSIONS The results lead to the conclusions that: (1) E1 enamel is hypomineralized, and its degree of calcification is restored by return to a normal calcium diet; (2) intra- and interprismatic calcification occurs in a different way; (3) crystallite thickness is initially greater in dentinal than in the superficial zone and is reversed as crystallite growth is completed; and (4) loss of enamel proteins is necessary for completion of crystallite growth and not for crystallite formation.
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Affiliation(s)
- E Bonucci
- Department of Experimental Medicine and Pathology, University La Sapienza, Rome, Italy
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39
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Aoba T. Strategies for improving the assessment of dental fluorosis: focus on chemical and biochemical aspects. Adv Dent Res 1994; 8:66-74. [PMID: 7993562 DOI: 10.1177/08959374940080011201] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In order to assess fluoride accumulation and effects in developing dental tissues, one must determine the concentration profile of fluoride in the tissue and to assess separately the labile (i.e., free ions in fluid and ions associated with organic matter) and stable (i.e., incorporated into apatite lattice) pools of fluoride. Free fluoride ions in the mineralizing milieu markedly affect the driving force for precipitation and, as a result, the nature of precipitating crystals. The fluoride incorporated into the crystalline lattice increases the stability of the formed mineral. Improvement in the understanding of the mechanism of dental fluorosis requires more comprehensive information about the effects of fluoride on the ionic composition of the fluid phase, the nature of the initially precipitating mineral(s), the interactions between crystals and matrix proteins, and the enzymatic degradation of the proteins. Recent observations relevant to the role of fluoride in enamel formation include: (1) that there are threshold concentrations of fluoride below which the precipitation and hydrolysis of thin-platy octacalcium phosphate is facilitated but beyond which de novo apatite precipitation prevails; (2) that the presence of fluoride in the mineralizing milieu most likely affects the steady-state concentrations of mineral lattice ions; (3) that incorporation of fluoride into the stable pool is retarded by the presence of matrix proteins, particularly amelogenins, which inhibit the growth of apatite crystals; (4) that increasing the degree of fluoridation of apatite crystals enhances the adsorption of amelogenins onto the crystal surface, and (5) that amelogenins pre-adsorbed onto apatite crystals are more resistant to enzymatic cleavages by trypsin (used as a prototype of amelogeninases).
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Affiliation(s)
- T Aoba
- Nippon Dental University, Department of Pathology, Tokyo, Japan
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40
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41
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Abstract
Amelogenins were extracted from the thin outer layer of porcine secretory enamel and purified by gel filtration and reverse-phase HPLC. The results of amino acid sequencing of the purified porcine amelogenins indicated the presence of at least four prototype amelogenins translated from alternatively spliced transcripts. The results of mass spectroscopy of the CNBr-cleaved peptides derived from the 25 kDa amelogenin indicated that porcine 25 kDa amelogenin is neither phosphorylated nor glycosylated.
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Affiliation(s)
- Y Yamakoshi
- Department of Biochemistry, School of Dental Medicine, Tsurumi University, Yokohama, Japan
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42
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Nanci A, Zalzal S, Kogaya Y. Cytochemical characterization of basement membranes in the enamel organ of the rat incisor. HISTOCHEMISTRY 1993; 99:321-31. [PMID: 8500995 DOI: 10.1007/bf00269105] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ameloblasts are unique epithelial cells, in that once they have deposited the entire thickness of enamel and the process of maturation begins, they reform a basal lamina-like structure at their apical surface. In order to characterize further this basal lamina, its composition was analysed using (1) lectin-gold cytochemistry for glycoconjugates, (2) high-iron diamine (HID) staining for sulfated glycoconjugates and (3) immunogold labeling for collagen type IV and laminin. The labeling patterns were compared to that of other more "typical" basement membranes found in the enamel organ. Sections of rat incisor enamel organs embedded in Lowicryl K4M were stained with Helix pomatia agglutinin (HPA), Ricinus communis I agglutinin (RCA), wheat germ agglutinin (WGA) and Ulex europaeus I agglutinin (UEA). Samples from the late maturation stage were also reacted en bloc with lectins and embedded in Epon for transmission electron microscopic examination or prepared for scanning electron microscopy. Such samples were also stained with HID and conventionally processed for Epon embedding. Tissue sections were then reacted with thiocarbohydrazide-silver proteinate (TCH-SP). Analysis of the lectin labeling suggested that the region of extracellular matrix immediately adjacent to ameloblasts, where the basal lamina is situated, was intensely reactive with HPA and RCA, moderately reactive with WGA, and weakly reactive with UEA. In general, other basement membranes were mildly reactive with all lectins used. No HID-TCH-SP staining was observed directly over the basal lamina while numerous stain deposits were present over other basement membranes of the enamel organ. Immunolocalization of collagen type IV and laminin yielded a weak and variable labeling over the basal lamina.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A Nanci
- Department of Stomatology, Université de Montréal, QC, Canada
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