Function of β1 Integrin in Oral Epithelia and Tooth Bud Morphogenesis

Abstract

Integrin β1 is critical for basement membrane organization and hair follicle morphogenesis in the skin epidermis; however, less is known about its function in the developing oral epithelium. Since the skin and oral epithelia share structural similarity, we hypothesized that β1 integrin function would be critical for the normal development of oral epithelium and tooth buds. The conditional (oral mucosa-specific) β1 integrin knockout (KO) mice displayed severe disruption of the basement membrane of the tongue epithelium and developing tooth buds. Interestingly, unlike the developing hair follicles, early morphological development of the KO molar tooth buds was normal. However, subsequent morphogenetic events, such as cusp formation, cervical loop down-growth, and ameloblast polarization, did not occur normally. Primary KO oral keratinocytes showed defective cell spreading and robust focal adhesions. Our studies indicate that β1 integrin plays an essential role in the normal development of the oral epithelium and its appendages.