title: Distribution of small integrin-binding ligand, N-linked glycoproteins (SIBLING) in the articular cartilage of the rat femoral head.
abstract: The small integrin-binding ligand, N-linked glycoprotein (SIBLING) family is closely related to osteogenesis. Until recently, little was known about their existence in articular cartilage. In this study, we systematically evaluated the presence and distribution of four SIBLING family members in rat femoral head cartilage: dentin matrix protein 1 (DMP1), bone sialoprotein (BSP), osteopontin (OPN), and dentin sialophosphoprotein (DSPP). First, non-collagenous proteins were extracted and then separated by ion-exchange chromatography. Next, the protein extracts eluted by chromatography were analyzed by Stains-all staining and Western immunoblotting. IHC was used to assess the distribution of these four SIBLING family members in the femoral head cartilage. Both approaches showed that all the four SIBLING family members are expressed in the femoral head cartilage. IHC showed that SIBLING members are distributed in various locations throughout the articular cartilage. The NH₂-terminal fragments of DMP1, BSP, and OPN are present in the cells and in the extracellular matrix, whereas the COOH-terminal fragment of DMP1 and the NH₂-terminal fragment of DSPP are primarily intracellularly localized in the chondrocytes. The presence of the SIBLING family members in the rat femoral head cartilage suggests that they may play important roles in chondrogenesis.
authors.affiliation: Dept. of Biomedical Sciences, Baylor College of Dentistry, Texas A&M University System Health Science Center, Dallas, TX 75246, USA.
authors.forename: Yao
authors.initials: Y
authors.lastname: Sun
authors.forename: Su
authors.initials: S
authors.lastname: Ma
authors.forename: Jin
authors.initials: J
authors.lastname: Zhou
authors.forename: Albert K
authors.initials: AK
authors.lastname: Yamoah
authors.forename: Jian Q
authors.initials: JQ
authors.lastname: Feng
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hinton
authors.forename: Chunlin
authors.initials: C
authors.lastname: Qin
mesh_terms: D000375:Aging; D000818:Animals; D002358:Cartilage, Articular / Q000254:growth & development / Q000378:metabolism*; D020219:Chondrogenesis; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005270:Femur Head / Q000254:growth & development; D058574:Integrin-Binding Sialoprotein; D008297:Male; D010012:Osteogenesis; D053495:Osteopontin / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000378:metabolism*; D000099311:Dentin Sialophosphoprotein
chemical_list: D016326:Extracellular Matrix Proteins; D058574:Integrin-Binding Sialoprotein; D053495:Osteopontin; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C081635:Dmp1 protein, rat; C546873:Ibsp protein, rat