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.