Expression patterns of the Stim1 protein during different stages of mouse tooth development

Objectives: Stromal interaction molecule 1 (STIM1), a calcium sensor protein, was shown to be significantly up-regulated during the maturation stage of amelogenesis. This result highlighted a potentially important role for STIM1 in calcium ion handling during the latter stages of enamel formation. Our work aimed to study in detail the expression patterns of STIM1 during all stages of mouse tooth development.
Material and Methods: C57BL mice were used for all the experiments in this study. The embryos were obtained from time mated pregnant mice. Embryonic day 0 (E0) was designated as the day on which a vaginal plug was confirmed. Embryos at E12.5, E14.5, E15.5 and pups at PNO, PN4, PN8 and PN14 were used to describe different developmental stages of incisors (E12.5 – E15.5) and molars (PN0 – PN14).
Results: Stim1 signals start to be detectable in the cells of the enamel organ at the beginning of the cap stage. Its expression was similar between the incisor and molar tooth germs. Odontoblasts appeared completely negative, while there was some strong expression in the middle of the dental papilla.
Conclusion: In our study, we have shown that Stim1 was most highly expressed in the ameloblasts during the maturation stage. This highly expression of Stim-1 at the maturation stages of enamel development supports the contention that stored operated calcium channels are central to Ca2+ transport/extrusion mechanism during the final phase of enamel crystal growth.