Synapse-Enriched m<sup>6</sup>A-Modified Malat1 Interacts with the Novel m<sup>6</sup>A Reader, DPYSL2, and Is Required for Fear-Extinction Memory
Sachithrani U. Madugalle, Wei‐Siang Liau, Qiongyi Zhao, Xiang Li, Hao Gong, Paul R. Marshall, Ambika Periyakaruppiah, Esmi L. Zajaczkowski, Laura J. Leighton, Haobin Ren, Mason Musgrove, Joshua Davies, Gwangmin Kim, Simone Rauch, Chuan He, Bryan C. Dickinson, Barbora Fulopova, Lee N. Fletcher, Stephen R. Williams, Robert C. Spitale, Timothy W. Bredy
Abstract
The RNA modification N 6 -methyladenosine (m 6 A) regulates the interaction between RNA and various RNA binding proteins within the nucleus and other subcellular compartments and has recently been shown to be involved in experience-dependent plasticity, learning, and memory. Using m 6 A RNA-sequencing, we have discovered a distinct population of learning-related m 6 A- modified RNAs at the synapse, which includes the long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 ( Malat1 ). RNA immunoprecipitation and mass spectrometry revealed 12 new synapse-specific learning-induced m 6 A readers in the mPFC of male C57/BL6 mice, with m 6 A-modified Malat1 binding to a subset of these, including CYFIP2 and DPYSL2. In addition, a cell type- and synapse-specific, and state-dependent, reduction of m 6 A on Malat1 impairs fear-extinction memory; an effect that likely occurs through a disruption in the interaction between Malat1 and DPYSL2 and an associated decrease in dendritic spine formation. These findings highlight the critical role of m 6 A in regulating the functional state of RNA during the consolidation of fear-extinction memory, and expand the repertoire of experience-dependent m 6 A readers in the synaptic compartment. SIGNIFICANCE STATEMENT We have discovered that learning-induced m 6 A-modified RNA (including the long noncoding RNA, Malat1 ) accumulates in the synaptic compartment. We have identified several new m 6 A readers that are associated with fear extinction learning and demonstrate a causal relationship between m 6 A-modified Malat1 and the formation of fear-extinction memory. These findings highlight the role of m 6 A in regulating the functional state of an RNA during memory formation and expand the repertoire of experience-dependent m 6 A readers in the synaptic compartment.