Title: CELF Control in the Neuron
Description: CELF4 is a brain-specific member of the CELF RNA binding protein (RBP) family that binds a significant portion of the transcriptome with striking selectivity for the 3’UTR of neuronal and synapse-specific functional targets in the hippocampus. Celf4 knockout and haploinsufficient mice have a complex neurobehavioral phenotype similar to human patient groups identified with CELF4 mutations, specifically CELF4-inclusive deletions and translocations. We hypothesize that CELF4 operates in multiple aspects of post-transcriptional gene regulation; interacting with RNA molecules from synthesis to decay. Tissue-level ribosome profiling experiments demonstrate that loss of CELF4 results in global ribosome occupancy changes across CELF4 mRNA targets and refined our ability to interrogate the synaptic function of CELF4. Turning intra-cellularly, a snRNA-seq approach implicated the CA3 region of the hippocampus in CELF4-mediated mRNA regulation and identified synaptic targets regulated by CELF4. By leveraging both ribosome profiling footprinting and snRNA-seq differential gene expression data, we identified synaptic and epilepsy disease genes that contribute to, and drive, neurobehavioral phenotypes.

In part two of this work we focus on DEE disease gene DNM1, a known target of CELF4 at the synapse. Using in vitro and in vivo approaches, we validate the regulatory relationship between mouse Dnm1 RNA and CELF4 RBP function. Lastly, we introduce a novel preclinical model of DNM1 DEE that recapitulates the seizure and behavioral phenotypes of patients suffering from dominant negative DNM1 mutations. In characterization of this model, we lay the groundwork for future investigations of cellular etiology of DNM1 pathogenic variants and therapeutic development for patient groups suffering from DEE.