DIFFERENTIAL INTRACELLULAR SORTING OF IMMEDIATE-EARLY GENE MESSENGER-RNAS DEPENDS ON SIGNALS IN THE MESSENGER-RNA SEQUENCE

This study characterizes the differential targeting of recently synthe sized immediate early gene (IEG) mRNAs to neuronal cell bodies versus dendrites and tests the hypothesis that this targeting is based on sig nals in the encoded proteins. A single electroconvulsive seizure induc es the expression of a number of IEG mRNAs in granule cells of the den tate gyrus. Most of these IEG mRNAs remain in the cell body, including two that are characterized in the present study (the mRNAs for NGFI-A and COX-2). In contrast, the mRNA for Are moved rapidly into dendrite s at an apparent rate of similar to 300 mu m/hr. Inhibiting protein sy nthesis with cycloheximide did not disrupt the differential mRNA sorti ng, demonstrating that the differential targeting of mRNAs is not depe ndent on translation.