NEUROTROPHIN-3 SIGNALS REDISTRIBUTE RNA IN NEURONS

The translocation of specific mRNAs to dendrites and their potential f or locally regulated translation are likely to serve as an effector in neuronal plasticity. Whether translation in dendrites is regulated by delivery of the RNA to sites of plasticity or a stationary pool of lo calized RNA undergoes enhanced translational efficiency is not clear. We show that RNA can translocate into dendrites in response to NT-3, R NA granules were visualized in cultured rat cortical neurons using the dye SYTO 14, which labels poly-ribosome complexes. Long before the mo rphological effects of NT-3 appeared, there was increased distal trans location of labeled complexes. This effect was blocked by K252a, a pot ent inhibitor of tyrosine kinase receptors. Therefore, neurons can uti lize extracellular signals to alter the distribution of protein synthe tic machinery via the active transport of RNA granules.