title: The function and interrelationship between GDF5 and ERG-010 during chondrogenesis in vitro.
abstract: Joint formation begins with the establishment of an interzone within the cartilaginous anlagen of the future skeleton. Both GDF5 and ERG are proposed as regulators of chondrocyte differentiation during and post interzone formation. The aim of this study was to examine the relationship between Gdf5 and Erg expression and downstream effects on chondrocyte gene expression. Erg expression was identified in mouse knee joints at E13.5. Expression analyses were performed using micromass cultures of murine C3H10T1/2 mesenchymal cells undergoing induced chondrogenesis in the presence and absence of GDF5 and ERG. At E13.5, Erg expression was found to surround epiphyseal chondrocytes and span the interzone up to the intermediate zone. Erg splice forms were expressed in micromass cultures, and their expression profile was altered by the addition of recombinant GDF5 depending on the stage of differentiation. Overexpression of Erg-010 resulted in a downregulation of Col2a1 and Col10a1. Microarray analysis following Erg-010 overexpression identified two potential downstream targets, Ube2b and Osr2, which were also differentially regulated by GDF5. Erg regulation by GDF5 in induced mesenchymal cells in vitro is dependent on the stage of chondrogenesis, and its expression in vivo demarcates chondrocytes that are not destined to be consumed by endochondral ossification. Functionally, Erg expression causes downregulation of Col2a1 and Col10a1 expression and this effect is potentially mediated by Osr2 and/or Ube2b. Combined, these data suggest a possible pathway linking GDF5, ERG and downstream factors in the processes of chondrocyte differentiation during articular joint formation.
authors.affiliation: Wellcome Trust Centre for Cell Matrix Research, University of Manchester, Manchester, M13 9PL, UK. mark.howard@sbcna.com.|Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, 450 Technology Drive, Room 221, Pittsburgh, PA, 15219, USA. mark.howard@sbcna.com.|Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK. mark.howard@sbcna.com.
authors.forename: Mark
authors.initials: M
authors.lastname: Howard
authors.affiliation: Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, 450 Technology Drive, Room 221, Pittsburgh, PA, 15219, USA. rst13@pitt.edu.
authors.forename: Rocky S
authors.initials: RS
authors.lastname: Tuan
authors.affiliation: Wellcome Trust Centre for Cell Matrix Research, University of Manchester, Manchester, M13 9PL, UK. g.wallis@manchester.ac.uk.
authors.forename: Gillian A
authors.initials: GA
authors.lastname: Wallis
mesh_terms: D000818:Animals; D002356:Cartilage / Q000254:growth & development / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics*; D019902:Chondrocytes / Q000378:metabolism; D020219:Chondrogenesis / Q000235:genetics*; D024043:Collagen Type II / Q000096:biosynthesis; D024121:Collagen Type X / Q000096:biosynthesis; D047108:Embryonic Development / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D055428:Growth Differentiation Factor 5 / Q000096:biosynthesis* / Q000235:genetics; D007719:Knee Joint / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D015513:Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D000071230:Transcriptional Regulator ERG
chemical_list: C570620:Col10a1 protein, mouse; C447413:Col2a1 protein, mouse; D024043:Collagen Type II; D024121:Collagen Type X; C531115:ERG protein, mouse; C525894:Gdf5 protein, mouse; D055428:Growth Differentiation Factor 5; D015513:Oncogene Proteins; D014157:Transcription Factors; D000071230:Transcriptional Regulator ERG
keywords: Articular cartilage; Chondrogenesis; Endochondral ossification; Erg; Gdf5