Selective dendritic localization of mRNA in Drosophila Mushroom Body Output Neurons

Memory-relevant neuronal plasticity is believed to require local translation of new proteins at synapses. Understanding this process requires the visualization of the relevant mRNAs within these neuronal compartments. Here we used single-molecule fluorescence <i>in situ</i> hybridization (smFISH) to localize mRNAs at subcellular resolution in the adult <i>Drosophila</i> brain. mRNAs for subunits of nicotinic acetylcholine receptors and kinases could be detected within the dendrites of co-labelled Mushroom Body Output Neurons (MBONs) and their relative abundance showed cell-specificity. Moreover, aversive olfactory learning produced a transient increase in the level of <i>CaMKII</i> mRNA within the dendritic compartments of the gamma-5-beta-prime-2a MBONs. Localization of specific mRNAs in MBONs before and after learning represents a critical step towards deciphering the role of dendritic translation in the neuronal plasticity underlying behavioural change in <i>Drosophila</i>. <br>