NEURALIZED MESSENGER RIBONUCLEIC ACID IS LOCALIZED IN DENDRITES BUT IS NOT TARGETED TO ACTIVE SYNAPSES.

Abstract

Previous studies have revealed that a small subset of mRNAs expressed by neurons are transported into dendrites. One of these (the mRNA for activity-regulated cytoskeleton-associated gene Arc) has a unique property in that it is rapidly targeted to active synapses, but only a few of the known dendritic mRNAs have been tested. Here we assess whether the mRNA for a transcription factor (Neuralized), which has been shown to be present in dendrites, localizes to active synapses in the way that Arc does. A cloned cDNA encompassing 1.71 kilobases of the Neuralized gene was generated by RT-PCR and inserted into expression vectors for producing c-RNA probes for in situ hybridization. The probe was used for in situ hybridization of Sprague-Dawley rat brain sections collected from rats in which afferent pathways to the hippocampus had been strongly activated in a manner that causes Arc mRNA localization at the active dendrites. We found that stimulation patterns that induced dramatic reorganization of Arc mRNA did not cause any detectable alteration in the distribution of Neuralized mRNA. The expression pattern for Neuralized mRNA seems to resemble other mRNAs whose dendritic distribution is not affected by synaptic activation, including the mRNAs for CAM kinase II and dendrin. These results suggest that Arc mRNA possesses unique characteristics not shared by other dendritic mRNAs that have been tested to date. Supported by NIH-NS12333 to OS.