Neuronal Nsun2 deficiency is associated with codon-specific epitranscriptomic dysregulation of Gly-tRNAs and corresponding proteomic shift impacting synaptic signaling and behavior

The role of transfer (t)RNA cytosine methyl-transferases as epitranscriptomic regulators of brain proteomes remains unexplored. We report that fear memory and antidepressant-like behaviors are highly sensitive to bi-directional changes in Nsun2 tRNA methyltransferase activity in prefrontal cortex (PFC) neurons. Nsun2-deficient mutant cortex showed a selective deficit in multiple glycine tRNAs, resulting in codon-specific shifts in translational efficiencies and a distorted proteomic landscape with deficits in glycine-rich neuronal proteins impacting synaptic signaling and behavior.