Organic components of crystal sheaths in bones.
Crystals in bones are enveloped within organic crystal sheaths of 5-10 nm widths. In order to analyse their components, we investigated the immunolocalizations of chondroitin 4- and 6-sulphate, keratan sulphate, bone sialoprotein and osteopontin. All of these, except chondroitin 6-sulphate, were found in bone matrix. Although the localizations of chondroitin 4-sulphate and keratan sulphate tended to focus within calcified nodules, bone sialoprotein and osteopontin were widely distributed in the area, being linearly arranged along electron-dense structures corresponding to crystal sheaths. These two proteins possess the ability to affect nucleation or elongation of hydroxyapatite, positively or negatively, in vitro. Our results suggested that bone sialoprotein and osteopontin may combine to form the crystal sheaths which are thought to control crystal formation and growth, using the seemingly opposite functions of bone sialoprotein and osteopontin.
Hoshi
K
K
First Department of Oral Anatomy, Niigata University Faculty of Dentistry, Japan. pochi@dent.niigata-u.ac.jp
Ejiri
S
S
Ozawa
H
H
D000818:Animals; D001842:Bone and Bones / Q000737:chemistry* / Q000196:embryology / Q000648:ultrastructure*; D002809:Chondroitin Sulfates / Q000302:isolation & purification; D058574:Integrin-Binding Sialoprotein; D007632:Keratan Sulfate / Q000302:isolation & purification; D010012:Osteogenesis; D053495:Osteopontin; D051381:Rats; D017208:Rats, Wistar; D012795:Sialoglycoproteins / Q000302:isolation & purification
C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; D002809:Chondroitin Sulfates; D007632:Keratan Sulfate