Translating Memories

Formation of long-term memory clearly requires transcriptional responses in neurons, but the identity of the expressed genes has been difficult to track down. Dubnau et al. used a combined strategy in which they analyzed DNA microarrays for transcripts whose abundance was increased during formation of long-term memories and also screened for Drosophila mutants with impaired long-term memory. Several genes that showed up in both screens encode proteins that take part in transport and localized translation of mRNA, a process already implicated in memory storage mechanisms. One gene, pumilio, works to repress translation of specific transcripts, and another, staufen, encodes a protein that functions in translocation of mRNAs. Studies with temperature-sensitive staufen mutants showed that loss of that gene product during a one-day period after training blocked memory formation, effectively ruling out other nonspecific actions of the staufen mutation. The authors propose that particles containing mRNAs are transported to synapses activated during the learning stimulus. Components like pumilio may repress translation along the way until the complex reaches its appropriate synaptic target. Greenspan provides insightful commentary and amusing historical background. J. Dubnau, A.-S. Chiang, L. Grady, J. Barditch, S. Gossweiler, J. McNeil, P. Smith, F. Buldoc, R. Scott, U. Certa, C. Broger, T. Tully, The staufen/pumilio pathway is involved in Drosophila long-term memory. Curr. Biol. 13, 286-296 (2003). [Online Journal] J. Greenspan, RNA and memory: From feeding to localization. Curr. Biol. 13, R126-R127 (2003). [Online Journal]