Expression, localization and synthesis of small leucine-rich proteoglycans in developing mouse molar tooth germ

The gene expression and protein synthesis of small leucine-rich proteoglycans (SLRPs), including decorin, biglycan, fibromodulin, and lumican, was analyzed in the context of the hypothesis that they are closely related to tooth formation.In situ hybridization, immunohistochemistry, and organ culture with metabolic labeling of [35S] were carried out in mouse first molar tooth germs of different developmental stages using ICR mice at embryonic day (E) 13.5 to postnatal day (P) 7.0. At the bud and cap stage,decorin mRNA was expressed only in the surrounding mesenchyme, but not within the tooth germ.BiglycanmRNA was then expressed in the condensing mesenchyme and the dental papilla of the tooth germ. At the apposition stage (late bell stage), bothdecorinand biglycanmRNA were expressed in odontoblasts, resulting in a switch of the pattern of expression within the different stages of odontoblast differentiation.DecorinmRNA was expressed earlier in newly differentiating odontoblasts thanbiglycan. With odontoblast maturation and dentin formation,decorinmRNA expression was diminished and localized to the newly differentiating odontoblasts at the cervical region. Simultaneously,biglycanmRNA took over and extended its expression throughout the new and mature odontoblasts. Both mRNAs were expressed in the dental pulp underlying the respective odontoblasts. At P7.0, both mRNAs were weakly expressed but maintained their spatial expression patterns. Immunostaining showed that biglycan was l...
Source: European Journal of Histochemistry - Category: Biomedical Science Source Type: research