CHAI'S DESIGNER MICE SPOTLIGHTED IN JOURNAL OF DENTAL RESEARCH
Animal model shows gene's role in forming healthy tooth enamel.
3/01/08
By Beth Dunham

This month, the Journal of Dental Research (JDR) features the work of Yang Chai, whose genetically engineered mice shed light on the molecular workings behind a devastating dental disease.

Not only does "Epithelial Fibroblast Growth Factor Receptor 1 Regulates Enamel Formation" appear in the March issue of JDR, but one of its images appears on the cover of the issue as well.

The mouse model demonstrates a specific gene's crucial regulatory role in the formation of the animal's tooth enamel, says Chai, Director of the School of Dentistry's Center for Craniofacial Molecular Biology.  The failure of the gene causes the mice to have symptoms of amelogenesis imperfecta, a disease that can also cause serious problems for human teeth.

"In amelogenesis imperfecta, the tooth enamel does not form properly; the enamel appears chalky instead of hard and shiny and the teeth are very vulnerable to decay," he says.  "It's a very difficult condition to treat."

When a gene called epithelial fibroblast growth factor receptor 1 (FGFR1) is completely inactive in a mouse embryo, the embryo dies after only 7 to 9 days of gestation.  However, in the genetically engineered mice, called K14-Cre;Fgfr1fl/fl mice, the FGFR1 gene inactivation takes place only in certain kinds of tissue, enabling the mice to grow to adulthood and be analyzed for amelogenesis imperfecta symptoms.

All of the mice with the inactivated gene displayed the symptoms, including weak, chalky enamel and rough, pitted teeth, Chai says, confirming FGFR1's role in tooth enamel development.