WD repeat-containing protein 72 (WDR72) has been localized in enamel organ, kidney and brain although its physiological function is not known. Mutations in the human WDR72 gene result in amelogenesis imperfecta. The affected enamel is poorly mineralized, indicating a potential role of WDR72 at the maturation stage of enamel formation. Our preliminary structure predictions suggest that WDR72 functions as a vesicle coatomer, like its homolog WDR7, playing a role in vesicle trafficking. To investigate the potential role of WDR 72 in vesicle trafficking in ameloblasts, we will use the homozygous mouse line with a Wdr72 null allele, which we generated from the NIH funded Knockout Mouse Project (KOMP), since our previous submission. We will determine whether WDR72 co-localizes with intracellular vesicles of ameloblasts. The role of WDR72 in the enamel matrix removal by forming endocytotic vesicles, and the potential function of these vesicles in either removing hydrolyzed amelogenins, or transporting proteinases to the maturation stage enamel matrix will be investigated. The long-term goal of this proposal is to determine the function of WDR72 in tooth organ development. These studies will also shed light on the role of WDR72 in other organ systems. To test the hypothesis that WDR72 is involved in vesicle trafficking, we will focus on the following 2 specific aims: 1) To determine whether WDR72 mediates vesicle trafficking in ameloblasts;2) To determine the effects of WDR72 on enamel matrix protein deposition, processing and reabsorption These findings in these studies will direct our understanding of the role of WDR72 on enamel matrix removal, vesicle trafficking and enamel mineralization, We anticipate that these studies will lead to a larger R01 proposal on the role of WDR72 in teeth, and translational studies related to amelogenesis imperfecta. .

Public Health Relevance

Alterations in WDR72 expression have been linked to amelogenesis imperfecta. However, the function of WDR72 is not known. In these proposed studies, we will use a WDR72 knockout mouse model to determine the cellular function of WDR72 and its function in enamel formation and biomineralization.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21DE023411-01A1
Application #
8702834
Study Section
Skeletal Biology Development and Disease Study Section (SBDD)
Program Officer
Wan, Jason
Project Start
2014-03-01
Project End
2016-02-29
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
1
Fiscal Year
2014
Total Cost
$197,083
Indirect Cost
$72,083
Name
University of California San Francisco
Department
Dentistry
Type
Schools of Dentistry
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Katsura, K A; Horst, J A; Chandra, D et al. (2014) WDR72 models of structure and function: a stage-specific regulator of enamel mineralization. Matrix Biol 38:48-58