On the nature and differential distribution of mRNAs in hippocampal neurites: implications for neuronal functioning

Neurons are highly polarized cells with a mosaic of cytoplasmic and membrane proteins differentially distributed in axons, dendrites, and somata. In Drosophila and Xenopus, mRNA localization coupled with local translation is a powerful mechanism by which regionalized domains of surface or cytoplasmic proteins are generated. In neurons, there is substantial ultrastructural evidence positing the presence of protein synthetic machinery in neuronal processes, especially at or near postsynaptic sites. There are, however, remarkably few reports of mRNAs localized to these regions. We now present direct evidence that an unexpectedly large number of mRNAs, including members of the glutamate receptor family, second messenger system, and components of the translational control apparatus, are present in individual processes of hippocampal cells in culture.