RNA protein interaction in neurons

Abstract

Neurons have their own systems for regulating RNA. Several multigene families encode RNA binding proteins (RNABPs) that are uniquely expressed in neurons, including the well-known neuron-specific markers ELAV and NeuN and the disease antigen NOVA. New technologies have emerged in recent years to assess the function of these proteins in vivo, and the answers are yielding insights into how and why neurons may regulate RNA in special ways-to increase cellular complexity, to localize messenger RNA (mRNA) spatially, and to regulate their expression in response to synaptic stimuli. The functions of such restricted neuronal proteins are likely to be complemented by more widely expressed RNABPs that may themselves have developed specialized functions in neurons, including Argonaute/microRNAs (miRNAs). Here we review what is known about such RNABPs and explore the potential biologic and neurologic significance of neuronal RNA regulatory systems.

Figure 1. Schematic of the HITS-CLIP Method

Schematic of major steps in HITS-CLIP (modified from (Licatalosi and Darnell, 2010); see SIDEBAR for details about CLIP). In brief, tissues or cells to be analyzed are irradiated with UV-light, inducing crosslinking between RNA-protein complexes within the cell, in situ. RNA is partially hydrolyzed, using nucleases or chemical hydrolysis, to a desired modal size (e.g. 30-50 nt), RNA-protein complexes are purified (typically by immunoprecipitation), RNA is labeled and run on autoradiograms to separate crosslinked RNA-protein complexes by size and transferred to nitrocellulose (through which any free RNA passes). The RNABP is the removed by Proteinase K treatment, RNA linker ligation is completed, and RNA PCR amplified and sequenced.