title: Temporal and spatial gene expression of major bone extracellular matrix molecules during embryonic mandibular osteogenesis in rats.
abstract: It is not known how gene expression of bone extracellular matrix molecules is controlled temporally and spatially, or how it is related with morphological differentiation of osteoblasts during embryonic osteogenesis in vivo. The present study was designed to examine gene expressions of type I collagen, osteonectin, bone sialoprotein, osteopontin, and osteocalcin during mandibular osteogenesis using in situ hybridization. Wistar rat embryos 13-20 days post coitum were used. The condensation of mesenchymal cells was formed in 14-day rat embryonic mandibles and expressed genes of pro-alpha 1 (I) collagen, osteonectin, bone sialoprotein and osteopontin. Cuboidal osteoblasts surrounding the uncalcified bone matrix were seen as early as in 15-day embryonic mandibles, while flat osteoblasts lining the surface of the calcified bone were seen from 16-day embryonic mandibles. Cuboidal osteoblasts expressed pro-alpha 1(I) collagen, osteonectin and bone sialoprotein intensely but osteopontin very weakly. In contrast, flat osteoblasts expressed osteopontin very strongly. Osteocytes expressed the extracellular matrix molecules actively, in particular, osteopontin. The present study demonstrated the distinct gene expression pattern of type I collagen, osteonectin, bone sialoprotein, osteopontin and osteocalcin during embryonic mandibular osteogenesis in vivo.
authors.affiliation: Division of Oral Molecular Biology, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: J X
authors.initials: JX
authors.lastname: Zhu
authors.forename: Y
authors.initials: Y
authors.lastname: Sasano
authors.forename: I
authors.initials: I
authors.lastname: Takahashi
authors.forename: I
authors.initials: I
authors.lastname: Mizoguchi
authors.forename: M
authors.initials: M
authors.lastname: Kagayama
mesh_terms: D000818:Animals; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D005314:Embryonic and Fetal Development; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D058574:Integrin-Binding Sialoprotein; D008334:Mandible / Q000196:embryology* / Q000378:metabolism; D010006:Osteoblasts / Q000378:metabolism; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics*; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism; D053495:Osteopontin; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism
chemical_list: D017931:DNA Primers; D016326:Extracellular Matrix Proteins; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D015676:Osteonectin; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D015675:Osteocalcin; D053495:Osteopontin; D003094:Collagen