Dynamic regulation of NAT10-mediated mRNA acetylation at synapses by learning and memory in mouse hippocampus

Precise regulation of protein synthesis is critical to a variety of brain functions including long-term memory. Dysregulated protein synthesis has been implicated in several disorders characterized by memory deficits. In contrast to mRNA methylation such as N6-methyladenosine (m6A) that was widely studied in memory, the regulation and function of mRNA acetylation in memory remain largely unknown. N4-acetylcytidine (ac4C), the only known form of RNA acetylation in eukaryotes, has recently been shown to regulate mRNA stability and translation efficiency. In this study, we identified the ac4C epitranscriptome through ac4C-RNA immunoprecipitation followed by next-generation sequencing (acRIP-seq) in the homogenates and synaptosomes of mouse hippocampus, a brain region critical for spatial memory. The task of Morris water maze (MWM) was employed to induce and evaluate memory acquisition and forgetting processes. Interestingly, the levels of ac4C mRNA were upregulated in the synaptosomes after memory formation but returned to normal levels after memories were naturally forgotten. The dynamic changes of ac4C-mRNAs regulated by memory were validated by ac4C dot-blot, Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), and acRIP-qPCR analysis. We further demonstrate that NAT10, the ac4C writer, in mouse hippocampus is important for spatial memory via regulating memory-related mRNAs, proteins, and ultimately synaptic plasticity. Lastly, we generated a freely-accessible website ( http://ac4catlas.com ) that included the dataset of ac4C epitranscriptome in mouse hippocampus. Altogether these results reveal a previously unappreciated mechanism underlying memory.