Objectives: Homo sapiens cyclin and CBS domain divalent metal cation transport mediator 4 (CNNM4) is a protein that is suggested to play an important role in Mg2+ ion transport. Mutations in this gene are associated with Jalili syndrome which consists of cone-rod dystrophy and enamel defects. These results highlighted the importance of the CNNM4 during enamel formation, so our work aimed to study the localisation of CNNM4 during different stages of lower incisor and first molar murine amelogenesis.
Material and Methods: Adult incisors (n: 16) of 4 week mice (C57BL) and pups at PNO, PN4 and PN14 were used to study Cnnm4 expression in different stages of mouse incisor and first molar respectively. The pups were obtained from time mated pregnant mice.
Results: In lower incisor, Cnnm4 was detected in ameloblast only in the maturation stage while in the secretory stage the signals was detected in a very specific way to stratum intermedium (SI). While in lower first molar, Cnnm4 was localised in inner enamel epithelium (pre-ameloblast) and stratum intermedium of the enamel organ at early bell stage (pre-secretory stage) while stellate reticulum and outer enamel epithelium were negative. In addition to that during the secretory stage, Cnnm4 signal was detected in secretory ameloblast under the cusp tip. Dental papilla, odontoblasts and dental follicles were appeared completely negative in both lower incisor and first molar.
Conclusion: CNNM4 has a specific expression pattern in enamel forming cells during different stages of teeth development in mice amelogenesis.