RbFox1-Nestin hippocampus. Mus musculus

Dysregulation of the brain-enriched RNA binding protein Rbfox1 has been linked to neurologic diseases such as epilepsy and autism spectrum disorders. However, it remains unexplored how distinct neuronal populations might contribute to neurologic dysfunction resulting from Rbfox1 loss. To examine these issues we profiled gene expression specifically in the hippocampus of wildtype and Rbfox1-/- mice. We identified transcripts whose expression was strongly Rbfox1-dependent and exhibited significant Rbfox1 binding in their 3’UTRs. One prominent target, Vamp1, was found to be specifically expressed in GABAergic interneurons. Both Vamp1 knockdown and Rbfox1 loss led to decreased synaptic transmission, and altered E/I balance in the Rbfox1-/- hippocampus, indicating that Vamp1 loss is a major component of the Rbfox1-/- physiological phenotype. The cytoplasmic isoform of Rbfox1 was sufficient to rescue Vamp1 expression in Rbfox1-/- neurons. We show that Rbfox1 binding in the Vamp1 3’UTR promotes its expression in part by antagonizing the brain-enriched microRNA-9. These results demonstrate that inhibitory neurons maintain specialized synaptic vesicle release machinery containing Vamp1 that is critically regulated by Rbfox1. Overall design: We performed RNA-seq to profile gene expression and splicing changes. Adult (P60-P70) hippocampal tissue was dissected from 3 pairs of male wildtype (Rbfox1 fl/fl; +/+) and Nes-cKO (Rbfox1 fl/fl; Nes/+) mice. Gene expression and splicing profiles were compared between wildtype and Nes-cKO. 6 total samples were analyzed.