Dental enamel is the hardest substance produced by the human body, but it does not start out that way. When it first begins forming on an unerupted developing tooth, enamel tissue is as soft as cheese. As the enamel matures, it becomes progressively harder and develops ultimately into a mineralized product.
Research on Proteinases in Enamel Development
Enamel matrix proteins, such as amelogenin, ameloblastin, and enamelin, are cleaved by proteinases soon after they are secreted. The cleavage products accumulate in the deeper, more mature enamel layers while the full-length proteins are only observed at the surface. This observation suggests that proteinases are necessary for “activating” enamel proteins so the parent proteins and their cleavage products may perform different functions.
We have cloned a novel matrix metalloproteinase enamelysin (MMP-20), from tooth tissues and have shown that it localizes primarily within the most recently formed enamel. We have found that MMP-20 transcripts are produced early in development in both the ameloblasts of the enamel organ and the odontoblasts of the pulp organ. These cell types are located adjacent to their respective mineralizing tissues; enamel and dentin, and each cell type is responsible for producing the organic components of its mineralizing matrix.
Ohio Wesleyan University, B.A., 1979, Zoology/Psychology
University of New Hampshire, M.S., 1984, Microbiology
University of Vermont, Ph.D., 1990, Cell & Molecular Biology
NSF Graduate Research Fellowship, 2001
HHMI Fellow, Life Sciences Research Foundation, 2006
Pew Scholar in the Biomedical Sciences, 2011