Subcellular localization of mRNA in neuronal cells. Contributions of high-resolution in situ hybridization techniques.

The development of technologies for high-resolution nucleic acid localization in cells and tissues has contributed significantly to our understanding of transcriptional and translational regulation in eukaryotic cells. These methods include nonisotopic in situ hybridization methods for light and electron microscopy, and fluorescent tagging for the study of nucleic acid behavior in living cells. In situ hybridization to detect messenger RNA has led to the discovery that individual transcripts may be selectively targeted to particular subcellular domains. In the nervous system, certain species of mRNA have been localized in distal processes in nerve cells and glia. Direct visualization of mRNA and its interactions with subcellular features, such as synaptic specializations, cytoskeletal elements, and nuclear pores, have been achieved. Of particular interest is the presence of mRNA and ribosomes in dendrites, beneath synaptic contacts, suggesting the possibility of synaptic regulation of protein synthesis. The following article will describe the application of high-resolution in situ hybridization and live imaging techniques to the study of mRNA targeting in neurons.