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To identify molecular mechanisms that control activity-dependent gene expression in the CNS, we have characterized the factors that mediate activity-dependent transcription of BDNF promoter III. We report the identification of a Ca(2+)-responsive E-box element, CaRE2, within BDNF promoter III that binds upstream stimulatory factors 1 and 2 (USF1/2) and show that USFs are required for the activation of CaRE2-dependent transcription from BDNF promoter III. We find that the transcriptional activity of the USFs is regulated by Ca(2+)-activated signaling pathways in neurons and that the USFs bind to the promoters of a number of neuronal activity-regulated genes in vivo. These results suggest a new function for the USFs in the regulation of activity-dependent transcription in neurons.

The primary objectives of the work described in this paper were to evaluate the concentration and diffusion coefficient of O2 in a commercial perfluorosulfonate ionomer (Nafion) and to assess the effect of a film of this ionomer on the rate of O2 reduction at a substrate Pt electrode surface. Electrochemical experiments at Nafion film‐coated electrodes were used to obtain these data. A high temperature film‐casting procedure, which has been shown to yield high quality solution‐cast Nafion films, was used to prepare the Nafion‐coated electrodes. The Nafion film‐coated electrodes were equilibrated with and exposed to 0.7M H3PO4 during the electrochemical experiments; it was of particular interest to compare the diffusion, solubility, and kinetic data obtained at the film‐coated electrode to analogous data obtained at a bare electrode, exposed to this electrolyte. We have found that the diffusion coefficient is lower in Nafion than in the electrolyte solution but that the solubility and oxygen reduction rate are higher.

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