Publication Date:
2017-03-12
Description:
Vacuolar H + -ATPases (V-ATPases) are ubiquitous multisubunit proton pumps responsible for organellar pH maintenance. Mutations in the a 3 subunit of V-ATPases cause autosomal recessive osteopetrosis; a rare disease due to impaired bone resorption. Patients with osteopetrosis also display dental anomalies, such as enamel defects; however, it is not clear whether these enamel abnormalities are a direct consequence of the a 3 mutations. We investigated enamel mineralization, spatiotemporal expression of enamel matrix proteins and the a 3 protein during tooth development using an osteopetrotic mouse model with a R740S point mutation in the V-ATPase a 3 subunit. Histology revealed aberrations in both crown and root development, whereas SEM analysis demonstrated delayed enamel mineralization in homozygous animals. Enamel thickness and mineralization were significantly decreased in homozygous mice as determined by µCT analysis. The expression patterns of the enamel matrix proteins amelogenin, amelotin, and odontogenic ameloblast-associated protein (ODAM) suggested a delay in transition to the maturation stage in homozygous animals. Protein expression of the a 3 subunit was detected in ameloblasts in all three genotypes, suggesting that a 3-containing V-ATPases play a direct role in amelogenesis, and mutations in a 3 delay transition from the secretory to the maturation stage, resulting in hypomineralized and hypoplastic enamel. This article is protected by copyright. All rights reserved
Electronic ISSN:
0091-7419
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
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