Subcommissural organ/Reissner's fiber complex: Characterization of SCO-spondin, a glycoprotein with potent activity on neurite outgrowth

• Published in: Glia Vol. 32; no. 2; pp. 177 - 191
• Main Authors: Gobron, Stéphane, Creveaux, Isabelle, Meiniel, Robert, Didier, Robert, Herbet, Alain, Bamdad, Mahchid, El Bitar, Fadia, Dastugue, Bernard, Meiniel, Annie
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.11.2000; Wiley-Liss
• Subjects: Age Factors; Amino Acid Sequence - physiology; Animals; Biological and medical sciences; Cattle; Cell Adhesion Molecules, Neuronal - chemistry; Cell Adhesion Molecules, Neuronal - metabolism; Central Nervous System - cytology; Central Nervous System - embryology; Central Nervous System - metabolism; Cerebral Aqueduct - cytology; Cerebral Aqueduct - embryology; Cerebral Aqueduct - secretion; Ependyma - cytology; Ependyma - embryology; Ependyma - secretion; ependymal secretion; Fetus; Fundamental and applied biological sciences. Psychology; Growth Cones - metabolism; Growth Cones - ultrastructure; Isolated neuron and nerve. Neuroglia; Molecular Sequence Data; Nerve Growth Factors - analysis; Nerve Growth Factors - chemistry; Nerve Growth Factors - metabolism; Neurites - drug effects; Neurites - metabolism; Neurites - ultrastructure; neuron-glia interaction; Peptide Fragments - analysis; Peptide Fragments - chemistry; Peptide Fragments - pharmacology; Reissner's fiber; SCO-spondin; Spinal Cord - cytology; Spinal Cord - embryology; Spinal Cord - metabolism; spondin; subcommissural organ; Subcommissural Organ - cytology; Subcommissural Organ - embryology; Subcommissural Organ - secretion; thrombospondin superfamily; Thrombospondins - analysis; Thrombospondins - chemistry; Thrombospondins - metabolism; Tumor Cells, Cultured - cytology; Tumor Cells, Cultured - drug effects; Tumor Cells, Cultured - metabolism; Vertebrates: nervous system and sense organs; Ependymal organ; Glial cell; Neurite; Growth; Secretion; Central nervous system; Glycoprotein; Cell cell interaction; Characterization; Reissner fiber; Neuron; Development; Ependyma; Subcommissural organ; Brain (vertebrata); Thrombospondin
• ISSN: 0894-1491; 1098-1136
• DOI: 10.1002/1098-1136(200011)32:2<177::AID-GLIA70>3.0.CO;2-V

In the developing vertebrate nervous system, several proteins of the thrombospondin superfamily act on axonal pathfinding. By successive screening of a SCO‐cDNA library, we have characterized a new member of this superfamily, which we call SCO‐spondin. This extracellular matrix glycoprotein of 4,560 amino acids is expressed and secreted early in development by the subcommissural organ (SCO), an ependymal differentiation located in the roof of the Sylvian aqueduct. Furthermore, SCO‐spondin makes part of Reissner's fiber (RF), a thread‐like structure present in the central canal of the spinal cord. This novel protein shows a unique arrangement of several conserved domains, including 26 thrombospondin type 1 repeats (TSR), nine low‐density lipoprotein receptor (LDLr) type A domains, two epidermal growth factor (EGF)‐like domains, and N‐ and C‐terminal von Willebrand factor (vWF) cysteine‐rich domains, all of which are potent sites of protein‐protein interaction. Regarding the huge number of TSR, the putative function of SCO‐spondin on axonal guidance is discussed in comparison with other developmental molecules of the CNS exhibiting TSR. To correlate SCO‐spondin molecular feature and function, we tested the effect of oligopeptides, whose sequences include highly conserved amino acids of the consensus domains on a neuroblastoma cell line B 104. One of these peptides (WSGWSSCSRSCG) markedly increased neurite outgrowth of B 104 cells and this effect was dose dependent. Thus, SCO‐spondin is a favorable substrate for neurite outgrowth and may participate in the posterior commissure formation and spinal cord differentiation during ontogenesis of the central nervous system. GLIA 32:177–191, 2000. © 2000 Wiley‐Liss, Inc.