Spatio-temporal expression of PHEX during tooth germ development in mouse

AIM:To investigate spatio-temporal expression and possible roles of PHEX during tooth germ development in mouse.METHODS:Expression of PHEX protein was detected by method of immunohistochemistry in different developmental stages of tooth germ in mouse.RESULTS:No positive staining of PHEX was found in bud stage.In cap stage PHEX expressed weakly and sporadically in inner/outer enamel epithelium and dental sac.In early bell stage,PHEX mainly expressed in inner enamel epithelium and dental sac.Weakly positive signals were also found in outer enamel epithelium,stratum intermedium and dental papilla cells adjacent to basement.In late bell stage PHEX which showed stronger positive expression gradually in ameloblasts and odontoblasts with the development of tooth germ.Expression of PHEX in enamel knots was stronger than in other positions.Positive PHEX expression was also detected in inner enamel epithelium at cervical loop,whereas it was negative in nearby dental papilla and outer enamel epithelium.CONCLUSION:Expression of PHEX in tooth germs has its special spatio-temporal patterns,which indicated that it might play an important role in tooth morphogenesis and mineralization.