Development of an artificial calcium-dependent transcription factor to detect sustained intracellular calcium elevation.

The development of a synthetic transcription factor that responds to intracellular calcium signals enables analyzing cellular events at the single-cell level or "rewiring" the intracellular information networks. In this study, we developed the calcium-dependent transcription factor (CaTF), which was cleaved by calpain and then translocated to the nuclei where it induced reporter expression. Our results demonstrated that CaTF-mediated reporter expression was stable and responded to the intracellular calcium level and calpain activity. In addition, CaTF detected the sustained calcium increase that was induced by physiological stimulation with epidermal growth factor (EGF). These results suggest that CaTF could be a useful tool to analyze intracellular calcium signals and be an interface between an endogenous signal network and synthetic gene network.