New frontiers in RNA transport and local translation in neurons.

RNA localization to neuronal dendrites and axons is increasingly recognized as a significant and widespread mechanism of gene expression control in neurons. High-throughput RNA sequencing is rapidly expanding the universe of known localized mRNAs. Although there are inherent difficulties in preparing sequencing libraries from dendrites and axons in the context of intact brain, genetic labeling strategies have paved the way for improved studies of this type. As the list of localized mRNAs grows, there is increasing need for functional validation of localized transcripts-that is, do particular localized transcripts serve demonstrable physiologic functions in axons or dendrites? Finally, specific details about what localized mRNAs do once they reach distal processes have long been elusive. Recent work using single-molecule imaging and other techniques is starting to fill in the picture of how transcripts navigate the localized environment and undergo activity-dependent translational de-repression.