Open AccessFAM20A is essential for amelogenesis, but is dispensable for dentinogenesis
Author(s) -
Lili Li,
Wuliji Saiyin,
Hua Zhang,
Shuzhen Wang,
Quanhua Xu,
Chunlin Qin,
Yongbo Lu
Publication year - 2019
Publication title -
journal of molecular histology
Language(s) - English
Resource type - Journals
eISSN - 1567-2387
pISSN - 1567-2379
DOI - 10.1007/s10735-019-09851-x
Subject(s) - ameloblast , amelogenesis , odontoblast , amelogenesis imperfecta , dentinogenesis , enamel paint , dentin , microbiology and biotechnology , dentinogenesis imperfecta , dental papilla , biology , mesenchyme , chemistry , anatomy , dentistry , medicine , embryo , osteogenesis imperfecta
Mutations in the gene encoding family with sequence similarity 20, member A (FAM20A) caused amelogenesis imperfecta (AI), in humans. However, the roles of FAM20A in amelogenesis and dentinogenesis are poorly understood. In this study, we generated a Fam20a knockout (Sox2-Cre;Fam20a fl/fl ) mouse model by crossing Fam20a fl/fl mice with Sox2-Cre transgenic mice, in which Fam20a 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 the Sox2-Cre;Fam20a fl/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, the Sox2-Cre;Fam20a fl/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.