FAM20A is essential for amelogenesis, but is dispensable for dentinogenesis

In this study, we generated aFam20a knockout (Sox2-Cre;Fam20afl/fl) mouse model by crossingFam20afl/fl mice withSox2-Cre transgenic mice, in whichFam20a was ablated in both dental epithelium and dental mesenchyme. We found that these mice developed an enamel phenotype that resembles human AI associated with FAM20A mutations, but did not have apparent dentin defects. The secretory stage ameloblasts in the mandibular incisors from theSox2-Cre;Fam20afl/fl mice were shorter and detached from the enamel matrix, and subsequently lost their polarity, became disorganized and formed numerous spherical extracellular matrices in place of normal enamel. At the molecular level, theSox2-Cre;Fam20afl/fl mice displayed dramatically reduced expression levels of the genes encoding the enamel matrix proteins, but unaltered levels of the genes encoding the dentin matrix proteins. Moreover,Fam20a ablation resulted in a great decrease in FAM20C protein level, but it did not alter the intracellular localization of FAM20C protein in ameloblasts and odontoblasts. These results indicate that FAM20A is essential for amelogenesis, but is dispensable for dentinogenesis.
Source: Journal of Molecular Histology - Category: Laboratory Medicine Source Type: research