Remote control of activity-dependent BDNF gene promoter-I transcription mediated by REST/NRSF

To know the role of repressor element-1 (RE-1)-silencing transcription factor (REST) in activity-dependent gene transcription in neurons, we investigated whether the Ca2+ signal-induced transcription of brain-derived neurotrophic factor promoter-I (BDNF-PI) is repressed by RE-1 located in exon II from far downstream of BDNF promoter-II (BDNF-PII). By constructing plasmids in which the location between BDNF-PI, -PII, and -RE-1 is maintained, we found, by conducting promoter assays with cortical neurons, that the promoter activity was constitutively repressed through the actions of BDNF-RE-1 but activated by Ca2+ signals evoked via membrane depolarization, which was due to BDNF-PI but not to BDNF-PII. The over-expression of REST reduced the level of transcriptional activation through the N- and C-terminals, suggesting the recruitment of a histone deacetylase. On over-expression of REST, an increased depolarization did not allow the activation. Thus, REST remotely represses activity-dependent gene transcription, the level of which controls the magnitude of the repression.