A recent essay described the process of cytoplasmic polyadenylation, and the functioning of the process in animal oocyte maturation and early development. Cytoplasmic control of translation is important, not only in the oocyte, but in other settings as well. One of these is in the neuron, where gene expression in repsonse to synaptic stimulation can be controlled by the activation of stored mRNAs in the cytoplasm. While details of this control have remained poorly understood, a suggestive requirement (well, it’s suggestive when it comes to the general subject of this blog) of CPEB for memory in Drosophila lends itself to the hypothesis that the activation of stored mRNAs in the neuron involves cytoplamsic polyadenylation.
It is thus of interest to see that Drosophila homologue of Gld2 (the cytoplasmic poly(A) polymerase mentioned here) is required for long-term memory. The abstract of the recent report follows. As always, enjoy.
The formation of long-term memory is believed to require translational control of localized mRNAs. In mammals, dendritic mRNAs are maintained in a repressed state and are activated upon repetitive stimulation. Several regulatory proteins required for translational control in early development are thought to be required for memory formation, suggesting similar molecular mechanisms. Here, using Drosophila, we identify the enzyme responsible for poly(A) elongation in the brain and demonstrate that its activity is required specifically for long-term memory. These findings provide strong evidence that cytoplasmic polyadenylation is critical for memory formation, and that GLD2 is the enzyme responsible.
J. E. Kwak, E. Drier, S. A. Barbee, M. Ramaswami, J. C. P. Yin, M. Wickens (2008). GLD2 poly(A) polymerase is required for long-term memory Proceedings of the National Academy of Sciences, 105 (38), 14644-14649 DOI: 10.1073/pnas.0803185105