The Expression Of Polarity Molecules Cdc42,Par3 And ZO-1 In The Development Of Runx2 Transgenic Mouse Odontoblasts

As the only cell to synthesize and secrete dentin matrix,odontoblast is the important foundation for tooth development and repair of dental pulp injury.And as the terminal differentiation and typical polar cells,odontoblasts experience the process of differentiation from nonpolar cells to polar cells,accompanied by the secretion and mineralization of dentin matrix.Runx2 is a regulatory factor that plays an important role in the development of teeth and some of the specific matrix proteins in the teeth are regulated by the transcriptional level.It has been found that there are differences in the expression of Runx2 in the process of tooth germ development,which not only play an important role in the differentiation of odontoblasts,but also play a significant role in the process of polarity.The formation of cell junctions and the location of polarity protein complexes is the essential step in the process of the apico-basal polarity establishment.As a kind of cell polarity switch molecules,the Rho protein family's small GTP enzyme-Cdc42 plays an important role in the process of cell polarity.Par3 is one of the important regulatory molecules in the above steps,and as an important protein molecule,ZO-1 also plays a crucial role in the process of cell polarity.Then what is the role of polar molecules Cdc42,Par3 and ZO-1 in odontoblast differentiation and maturation process? Whether Runx2 is involved in the regulation of odontoblasts' polarity process? This issue using a variety of molecular biology methods confirmed the expression of some polar molecules related to odontoblasts polarity establishment and Runx2,which may provide further understanding for the development of odontoblasts' process.1.The expression of polar molecules Cdc42,Par3 and ZO-1 in the development of wild mouse odontoblasts.After the extraction of total RNA was extracted from mature wild mice pulp and OLCs,the m RNA expression of Cdc42,Par3,ZO-1 were tested by PCR.With the tissue sections of mouse molar at prenatal 13 day,15day,18 day and postnatal 3day and 2 week,the expression of Cdc42,Par3,ZO-1 during the development of dental germ were detected by organ immunofluorescence.The results showed that the m RNA of Cdc42,Par3,ZO-1were expressed in both dental pulp and OLCs in mice,and Cdc42,Par3,ZO-1 participated in the whole process of mouse molar tooth germ development and the genesis process of odontoblast polarization.2.The expression of polar molecules Cdc42,Par3 and ZO-1 in the development of Runx2 transgenic mice odontolbasts.After the mice at prenatal 13 day,15 day,18 day and postnatal 3 day and 2 week were taken,we extracted the DNA from the mice tail tissue and identified the transgenic mice of the nest mice with PCR test.With the tissue sections of wild-type and transgenic mouse molar germ in different development stage,we took HE staining to find the histological morphology difference and the expression level difference of Cdc42,Par3 and ZO-1 in molar germ of different stages transgenic mice.At the same time,after extracting the molar germ m RNA from the mice of wild-type and transgenic mice at postnatal 3day,1week and 2 week stages,we took q RT-PCR to quantify the expression of Cdc42,Par3 and ZO-1.The results showed that the mice corresponding the strip of 461 bp were the transgenic mice.All of three polarity molecules were differently expressed in the development of Runx2 transgenic mouse molar germ.And in the process of odontoblast maturation,to Cdc42 and ZO-1,the molecule of Runx2 took inhibitory effect;To Par3,it took promoting effect at the early stage of odontoblast,contrarily it took inhibitory effect in later stage.In all,there probably were some certain correlation between Runx2 and three polarity molecules in the polarity process of odontoblasts.