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

The development of technologies for high-resolution nucleic acid localizati on 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 ele ctron microscopy, and fluorescent tagging for the study of nucleic acid beh avior in living cells. Ii I sifts hybridization to detect messenger RNA has led to the discovery that individual transcripts may be selectively target ed to particular subcellular domains. In the nervous system, certain specie s 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 pore s, have been achieved. Of particular interest is the presence of mRNA and r ibosomes in dendrites, beneath synaptic contacts, suggesting the possibilit y of synaptic regulation of protein synthesis. The following article will d escribe the application of high-resolution in situ hybridization and live i maging techniques to the study of mRNA targeting in neurons.