Transcriptome analysis reveals the population of dendritic RNAs and their redistribution by neural activity.

Subcellular localization of RNA is an efficient way to localize proteins to a specific region of a cell. The dendritic localization of RNAs underlies the establishment and maintenance of the synaptic functions of neuronal cells. A requirement for dendritic RNA localization and subsequent local translation has been demonstrated in several forms of experience-dependent synaptic plasticity. In spite of several attempts to identify these RNAs, the population of RNA species present in dendrites as a whole has not been well described. Here we show the results of microarray analyses with RNAs isolated from heavy portion of polysome (HP) fraction where RNA granules are enriched in and synaptosome fraction, prepared from the rat brain. These analyses revealed the complex nature of the dendritic RNA population, which included RNAs that were not expected to be in the dendrites. Neural activity caused by an electroconvulsive shock triggered a redistribution of the population of dendritic transcriptome towards the area of overlap between the HP and the synaptosome, which is assumed to be neck of spine. This redistribution may accompany some changes in the translatability of those transcriptome, which suggests complex mechanisms of local translation in response to synaptic inputs.