A NOVEL DISTAL ENHANCER REGION INVOLVED IN THE REGULATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR EXPRESSION

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that supports neuronal survival, differentiation, and synaptic plasticity during development and in the adult nervous system. Through these functions, BDNF plays an important role in learning and memory, and its dysregulation is associated with various neurodegenerative and neuropsychiatric disorders. The BDNF gene exhibits a highly complex, transcript-specific expression pattern across different cell types and in response to distinct stimuli. While the promoter regions of BDNF have been thoroughly investigated, BDNF enhancers have been less studied. Characterization of the complete set of enhancers involved in the precise regulation of BDNF would provide a better understanding of the mechanisms underlying its stimulus- and cell type-specific expression. Here, we used a chromatin conformation capture method named CAPTURE sequencing to identify putative enhancers that control BDNF expression in rat primary cortical neurons. Next, we focused on a distal upstream region, which showed the strongest interaction with the BDNF gene. We utilized publicly available transcriptomic and epigenetic data and performed histone modification ChIP sequencing and MAPCap sequencing to evaluate active enhancer-associated characteristics of the potential enhancer. Finally, we used CRISPR interference and activation systems to experimentally validate the region as a BDNF enhancer. Altogether, our findings reveal a novel enhancer of BDNF and show its multifaceted involvement in the control of BDNF expression in neurons.