A neural m(6)A/Ythdf pathway is required for learning and memory in Drosophila

Epitranscriptomic modifications can impact behavior. Here, we used Drosophila melanogaster to study N(6)-methyladenosine (m(6)A), the most abundant modification of mRNA. Proteomic and functional analyses confirm its nuclear (Ythdc1) and cytoplasmic (Ythdf) YTH domain proteins as major m(6)A binders. Assays of short term memory in m(6)A mutants reveal neural-autonomous requirements of m(6)A writers working via Ythdf, but not Ythdc1. Furthermore, m(6)A/Ythdf operate specifically via the mushroom body, the center for associative learning. We map m(6)A from wild-type and Mettl3 mutant heads, allowing robust discrimination of Mettl3-dependent m(6)A sites that are highly enriched in 5’ UTRs. Genomic analyses indicate that Drosophila m(6)A is preferentially deposited on genes with low translational efficiency and that m(6)A does not affect RNA stability. Nevertheless, functional tests indicate a role for m(6)A/Ythdf in translational activation. Altogether, our molecular genetic analyses and tissue-specific m(6)A maps reveal selective behavioral and regulatory defects for the Drosophila Mettl3/Ythdf pathway.