title: Recombinant expression and characterization of a novel fibronectin isoform expressed in cartilaginous tissues.
abstract: A novel fibronectin (FN) isoform lacking the segment from IIICS (type III connecting segment) through the I-10 module is expressed predominantly in normal cartilaginous tissues. We expressed and purified recombinant cartilage-type FN using a mammalian expression system and characterized its molecular and biological properties. Although FNs have been shown to be secreted as disulfide-bonded dimers, cartilage-type FN was secreted mainly as a monomer. It was less potent than plasma-type FN in promoting cell adhesion and binding to integrin alpha5beta1, although it was more active than plasma-type FN in binding to chondroitin sulfate E. When added exogenously, cartilage-type FN was poorly assembled into the fibrillar FN matrix, mostly because of its monomeric structure. Given that cartilage is characterized by its non-fibrillar matrix with abundant chondroitin sulfate-containing proteoglycans, it is likely that cartilage-type FN has evolved to adapt itself to the non-fibrillar structure of the cartilage matrix through acquisition of a novel mechanism of alternative pre-mRNA splicing.
authors.affiliation: Division of Protein Chemistry, Institute for Protein Research, Graduate School of Medicine, Osaka University, Suita, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kozaki
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Matsui
authors.forename: Jianguo
authors.initials: J
authors.lastname: Gu
authors.forename: Ryoko
authors.initials: R
authors.lastname: Nishiuchi
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sugiura
authors.forename: Koji
authors.initials: K
authors.lastname: Kimata
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ozono
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Kiyotoshi
authors.initials: K
authors.lastname: Sekiguchi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D016466:CHO Cells; D002356:Cartilage / Q000378:metabolism*; D002448:Cell Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000737:chemistry; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000096:biosynthesis* / Q000737:chemistry*; D019084:Fluorescent Antibody Technique, Indirect; D006025:Glycosaminoglycans / Q000378:metabolism; D006493:Heparin / Q000378:metabolism; D015151:Immunoblotting; D039081:Integrin alpha5beta1 / Q000378:metabolism; D051379:Mice; D008957:Models, Genetic; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms; D011509:Proteoglycans / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012326:RNA Splicing; D011994:Recombinant Proteins / Q000737:chemistry; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D004220:Disulfides; D005353:Fibronectins; D006025:Glycosaminoglycans; D039081:Integrin alpha5beta1; D010455:Peptides; D020033:Protein Isoforms; D011509:Proteoglycans; D011994:Recombinant Proteins; D012313:RNA; D006493:Heparin; D002809:Chondroitin Sulfates