The Expression Of Mineralization-Related Gene C4orf26 In Runx2 Knockout Mice In Ameloblasts

Objective:Runx2 is a transcription factor that plays an important role in osteoblasts differentiation and dental development.Runx2 gene mutations can lead to systemic hard tissue diseases including tooth,such as cleidocranial dysplasia(CCD).Runx2 mutations can show severe bone and tooth developmental disorders.The study have found that Runx2 knockout can lead to enamel mineralization disorders,but the mechanism of Runx2 in enamel development remains unclear,Studies have shown that mutations in the human C4orf26 gene cause severe attrition of enamel.Aims of this study:(1)to detect the spatio-temporal expression characteristics of C4orf26 in the enamel development in mice.(2)to further explore the mechanism of Runx2 in regulation enamel development in mouse ameloblasts by constructing Runx2 conditional knockout mice.Material and methods:(1)Collecting the mandibular molar region of the mouse PN10.Real-time PCR was used to detect changes in the expression of enamel matrix proteins in the ameloblasts of Runx2loxp/loxp mice and K14-cre,Runx2loxp/loxp mice.(2)Collecting the mandibular molar region,heart,liver,lung,brain,eyes and bone of C57BL/6 mice at PN10,and we used RT-PCR technique to detect the expression of C4orf26 in different organs.(3)Runx2loxp/loxp mice were used as research models.Immunohistochemistry(IHC)techniques were used for detecting the expression characteristics of C4orf26 protein in different developmental stages of mouse ameloblasts,and further to observe and analyze.Technique to detect the expression of C4orf26 protein in ameloblasts of Runx2 knockout mice.Results:(1)The real-time PCR showed that the expression levels of Amelx,Ambn and Enam mRNA were up-regulated,and the expression of Amtn,Odam,Scpppql and C4orf26 was down-regulated in K14-cre,Runx2loxp/loxp mice during the PN10 compared with Runx2loxp/loxp mice.The effect on C4orf26 gene expression was most pronounced.(2)RT-PCR results showed that C4orf26 was only expressed in the teeth.(3)The results of IHC showed that C4orf26 was expressed at the distal end of ameloblasts.In the apical part of the first molar of Runx2loxp/loxp mice at PN7 and PN10,C4orf26 significantly expressed in ameloblasts.A low point was detected at PN14;The staining of C4orf26 in K14-cre,Runx2l0xp/l0xp mouse ameloblasts was slightly weaker than that in wild-type mice.Conclusion:(1)Compared with wild-type mice,Amelx,Ambn,Enam,Amtn,Odam,Scpppql and C4orf26 in ameloblasts showed different degrees of change in Runx2-cKO mice,,and the Runx2 deletion had the most significant effect on C4orf26.(2)C4orf26 gene is mainly expressed in the basement membrane of mature ameloblasts,suggesting that C4orf26 may be involved in the exchange of ameloblasts and enamel during enamel mineralization.(3)After the deletion of Runx2 gene in ameloblasts,the expression of C4orf26 in the basement membrane of ameloblasts was weakened,indicating that the enamel mineralization disorder caused by Runx2 gene deletion may be closely related to the expression of C4orf26.