A boost in microRNAs shapes up the neuron

Neuronal activity regulates dendritic and synaptic development through both a global response in the form of transcription and a local control in the form of synaptic translation. Understanding how transcription and translation might be linked would provide new insight into signals connecting the nucleus to the synapse. Reported in this issue of The EMBO Journal, Fiore et al elucidate a novel mechanism controlling dendritic growth that involves the transcription factor, myocyte-enhancing factor (Mef2), which turns on the expression of a microRNA gene cluster after neuronal depolarization. One of these is miR-134, which turns off the translation of Pumilio2, a known translation repressor. MicroRNAs may thus fine-tune translational and transcriptional output needed for dendritogenesis.