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Osteopontin (OPN), a noncollagenous, extracellular matrix sialoprotein found at relatively high levels in both normal and pathological mineralized tissues, is expressed by tissue-specific cells in bone, calcified cartilage, and teeth. On the other hand, a hallmark of OPN expression in pathologically mineralizing tissue, and in other soft tissues(More)
BACKGROUND Bone sialoprotein (BSP) and osteopontin (OPN), two major noncollagenous proteins (NCPs) in collagen-based mineralized tissues, have been implicated in mineral deposition and cell- and matrix-matrix interactions during root development. However, their role in cementogenesis is still a subject of debate. Since distribution of proteins is indicative(More)
The aim of cytochemical techniques is to localize specific biochemical components in particular tissue and cell compartments. However, since preparation of tissues for structural observation results in major alterations of the properties of their components, a major problem is to retain an adequate degree of their biochemical properties as well as adequate(More)
As part of ongoing studies aimed at clarifying the early events of bone matrix deposition and mineralization, we have characterized primary osteoblast cultures using ultrastructural and immunocytochemical methods. Osteogenic cells were isolated by sequential enzymatic digestion of newborn rat (2-4-day-old) calvariae and grown for periods of 7 to 28 days on(More)
Mineralized tissues are unique in using proteins to attract and organize calcium and phosphate ions into a structured mineral phase. A precise knowledge of the expression and extracellular distribution of matrix proteins is therefore very important in understanding their function. The purpose of this investigation was to obtain comparative information on(More)
In the continuously erupting rat incisor the ameloblasts progress through distinct stages associated with the secretion and maturation of enamel. We have examined the possibility that the so-called "postsecretory" ameloblasts of the maturation stage of amelogenesis remain biosynthetically active and are engaged in the synthesis, secretion, and degradation(More)
The ultrastructural distribution of two noncollagenous proteins, osteopontin (OPN) and osteocalcin (OC), originally extracted from bone matrix and proposed to play an important role in bone formation, was examined in the matrices of bone and cartilage from embryonic and postnatal chicken tibial growth plates by high-resolution immunocytochemistry using the(More)
Currently available data describing the gene expression and regulation, secretion, distribution, and protein chemistry of osteopontin (OPN) all are consistent with the notions of this protein functioning as an inhibitor of mineralization and/or as a mediator of cell-matrix and matrix-matrix/mineral adhesion (cohesion) during the formation, turnover, and(More)
Among the noncollagenous matrix proteins found in mineralized tissues (MTs), colloidal-gold immunocytochemistry has demonstrated that the ultrastructural distribution of osteopontin (OPN) is unique in that this protein preferentially accumulates at MT interfaces. In bone, OPN is present as a major component of cell- and matrix-matrix interfacial structures(More)
Tooth morphogenesis results from reciprocal interactions between oral epithelium and ectomesenchyme culminating in the formation of mineralized tissues, enamel, and dentin. During this process, epithelial cells differentiate into enamel-secreting ameloblasts. Ameloblastin, an enamel matrix protein, is expressed by differentiating ameloblasts. Here, we(More)