Expression of Dentin Sialophosphoprotein in Mouse Nasal Cartilage and Tooth

Dentin sialophosphoprotein(DSPP) is generally regarded as a dentin specific protein,although low levels of expression have recently also been reported in bone.Our recent studies have also demonstrated the expression of DSPP in mouse nasal cartilage.However,the expression pattern in cartilage during development is unclear.Objectives: To investigate the pattern of DSPP expression in cartilage during development and to compare it with that in tooth germs at the same stages. Materials and Methods: Nasal cartilage and first molar tooth germs from day 18 embryonic and postnatal 1-12 day old Balb/C mice were dissected and RNA extracted with Trizol reagent according to the manufacturer's instructions.1µg of total RNA was used for oligo-dT reverse transcription to generate single stranded cDNA using the OmniscriptTM Reverse Transcriptase kit. Semi-quantitative RT-PCR for DSPP was then performed using the housekeeping gene glyceraldehydes-3-phosphate dehydrogenase (GAPDH) as a control. Results: The expression pattern of DSPP in cartilage was similar to that in tooth germs with the greatest expression in both nasal cartilage and tooth germs observed in postnatal 3 day old mice. However, greater differences between adjacent stages were seen in cartilage than in tooth germs. Conclusions: Although similar temporal expression profiles exist for DSPP in both mouse nasal cartilage and tooth germs, differences in the intensity of expression suggest that the gene may not be regulated similarly in these two tissues and requires further investigation.