Dentin sialophosphoprotein [designated DSPP and cleaved into dentin sialoprotein (DSP) and dentin phosphoprotein (DPP)], enamelysin and ameloblastin are each expressed in unique fashions during tooth development. It is possible that these components participate in cell differentiation and the conversion of unmineralized matrix into mineralized structures. In order to delineate the timing and the positioning of these three molecules in a physiological context, we compared their expression profiles by performing in situ hybridization experiments on consecutive sections in developing mouse tissues. Hybridization signals were uniquely detected for DSPP mRNA in odontoblasts and preameloblasts, for enamelysin mRNA in odontoblasts and in the facing ameloblast layer, and for ameloblastin mRNA in preodontoblasts, polarizing odontoblasts and ameloblasts. Immunohistochemistry showed that DSP and ameloblastin transcripts were translated into proteins that were deposited at the apical pole of the differentiated cells (odontoblasts and ameloblasts, respectively). The interrelated expression profiles found for these tooth-specific molecules illustrate the importance of a specific molecular network to initiate highly regulated processes such as cytodifferentiation and the subsequent mineralization.
The biological effects of isolated soluble dentin extracellular matrix components on the induction of reparative dentinogenesis in exposed cavities in ferret canine teeth have been shown to be blocked by immobilizing the extracellular matrix components on nitrocellulose or Millipore membranes during implantation. This contrasts with the picture of induction of odontoblast-like cell differentiation and reparative dentin deposition on existing insoluble dentin matrix of the exposure walls when the extracellular matrix components are implanted in lyophilized form. These data indicate the importance of an existing insoluble dentin matrix in providing a substrate to potentiate the growth factor-like activity of soluble isolated dentin extracellular matrix components in the induction of reparative dentinogenesis.
Eur J Oral Sci /998; /06 ( lllpp/1 ): 254 259 Printed m UK. All rights reserved Comparative analysis of mouse DSP and DPP expression in odontoblasts, preameloblasts, and experimentally induced odontoblast-like cells Begue-Kirn C. Rucll J-V. Rida/1 AL. Butler WT: Comparative analysis of mouse DSP and DPP expression in odontobla.\·ts, preameloblasts. and experimentally induced odontohlast-/ike cells. Eur J Oral Sci 1998: 106 (suppl l ): 254-259. 0 Eur J Oral Sci, 1998Dentin sialoprotein ( DSP) a nd dentin phosphoproteins (DPP) are uniquely expressed by differentiating a nd fu ll y differentia ted mature odontob lasts. Tt is li kely that DSP a nd DPP actively participate in the conversion of predentin to dentin . To compare the expression patterns of DPP a nd DSP, we constructed mouse eDNA probes. Northern analyses confirmed their specific expressions in tooth germ-derived RNA and showed that the probes reacted with si mila r or jdentica l multiple transcripts. In situ hybridiza tion indicated that DSP and DPP transcripts were uniquely detected and codistributed in developin g mouse odontoblasts and preameloblasts. These data, as well as the adj acent positioning of the DSP and DPP coding seq uences, suggest that common regulatory mechanisms co ntrol DSP and DPP expression . Dental pa pillae cultures, in which odonto blas t differentiation was experimenta ll y induced with TGF/31 combi ned with heparin , were used to show that the two molecules are also coexpressed under in vitro conditio ns.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.