Figure 4.

Three transcription factors bind to the BDNF promoter III CaREs and coordinately regulate transcription. Three elements within BDNF promoter III are required for calcium-dependent induction of a luciferase reporter gene, and three distinct transcription factors bind to these elements. “A” represents the novel calcium-regulated transcription factor that binds to CaRE1, and “B” represents the basic helix–loop–helix family member that binds the CaRE2/E-box element. CREB binds the CaRE3/CRE. In response to depolarization and the activation of calcium-signaling pathways, all three factors are activated to promote transcription, potentially through the phosphorylation-dependent recruitment of a common transcriptional coactivator.