Involvement of an Upstream Stimulatory Factor as Well as cAMP-responsive Element-binding Protein in the Activation of Brain-derived Neurotrophic Factor Gene Promoter I

Akiko Tabuchi,Hidemichi Sakaya,Tomochika Kisukeda,Hiroshi Fushiki,Masaaki Tsuda

doi:10.1074/jbc.m204784200

Abstract

The use of different brain-derived neurotrophic factor (BDNF) gene promoters results in the differential production of 5'-alternative transcripts, suggesting versatile functions of BDNF in neurons. Among four BDNF promoters I, II, III, and IV (BDNF-PI, -PII, -PIII, and -PIV), BDNF-PI was markedly activated, as well as BDNF-PIII, by Ca(2+) signals evoked via neuronal activity. However, little is known about the mechanisms for the transcriptional activation of BDNF-PI. Using rat cortical neurons in culture, we assigned the promoter sequences responsible for the Ca(2+) signal-mediated activation of BDNF-PI and found that the Ca(2+)-responsive elements were located in two separate (distal and proximal) regions and that the DNA sequences in the proximal region containing cAMP-responsive element (CRE), which is overlapped by the upstream stimulatory factor (USF)-binding element, were largely responsible for the activation of BDNF-PI. CRE-binding protein (CREB) family transcription factors and USF1/USF2 bind to this overlapping site, depending upon their preferred sequences which also control the magnitude of the activation. Overexpression of dominant negative CREB or USF reduced the BDNF-PI activation. These findings support that not only CREB but also USF1/USF2 contributes to Ca(2+) signal-mediated activation of BDNF-PI through the recognition of an overlapping CRE and USF-binding element.

Highlights

The use of different brain-derived neurotrophic factor (BDNF) gene promoters results in the differential production of 5؅-alternative transcripts, suggesting versatile functions of BDNF in neurons
Production of BDNF Transcripts Containing Exons I, II, III, and IV Induced via Membrane Depolarization— the complicated structure of the BDNF gene is suggested to give rise to at least eight species of BDNF transcript [4], it has already been reported that the exon III-containing transcript is the major form, the expression of which is controlled by BDNFPIII in response to the Ca2ϩ signals evoked via membrane depolarization in rat cortical neurons [8, 9]
By promoter assay using transient DNA transfection in cultures of rat cortical neurons, in addition, we demonstrated that Ca2ϩ-responsive elements of BDNF-PI were located in two regions, distal and proximal (Fig. 2)

Summary

Introduction

The use of different brain-derived neurotrophic factor (BDNF) gene promoters results in the differential production of 5؅-alternative transcripts, suggesting versatile functions of BDNF in neurons. CRE-binding protein (CREB) family transcription factors and USF1/USF2 bind to this overlapping site, depending upon their preferred sequences which control the magnitude of the activation.

Results

Conclusion