S100A1 expression in mouse embryos

Abstract

S100A1 protein is an EF‐hand type calcium‐binding protein with unique functions in adult tissues. However, its role in the embryonic development is largely unknown. To better understand its developmental role, we sought to determine the spatio‐temporal expression of S100A1 with reverse transcription‐PCR and specific immunohistochemical localization in normal and S100A1‐deficient mouse embryos which were generated previously by gene trap mutagenesis. The S100A1 mRNA started to express in normal embryos at E9.5 and was steadily increased until birth. At E15.5 and E17.5, S100A1 protein expression was observed in the heart, cartilages, bones, liver, lung and hindbrain. The expression was not detected in S100A1‐deficient embryos at all stages examined and S100A1‐deficient embryos did not exhibit any morphological anomalies. The S100B protein, which forms heterodimers with the S100A1 protein, was expressed in both normal and S100A1‐deficient embryos, indicating that the absence of the S100A1 protein did not influence S100B protein expression. Taken together, our results suggest that the widely expressed S100A1 protein in embryos may be a functionally redundant protein whose developmental functions can be supplemented by other proteins.Acknowledgements: The work was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project no. CUHK4421/05M).