INHIBITION OF PROTEIN-SYNTHESIS ALTERS THE SUBCELLULAR-DISTRIBUTION OF MESSENGER-RNA IN NEURONS BUT DOES NOT PREVENT DENDRITIC TRANSPORT OF RNA

This study evaluates whether protein synthesis plays a role in targeting RNA molecules to different subcellular domains within neurons. Transport of newly synthesized RNA (labeled with [H-3]uridine) was examined in the presence of the protein synthesis inhibitors puromycin and cycloheximide. In situ hybridization was used to determine whether inhibition of protein synthesis altered the subcellular distribution of mRNAs. Transport of recently synthesized RNA was not disrupted after prolonged exposure to either inhibitor. However, inhibition of protein synthesis caused several mRNAs that are normally confined to the cell body to appear in dendrites. The distribution of mRNAs that are normally present in dendrites was unaffected. These findings suggest that protein synthesis is not required to translocate RNA into the dendrites but may play a role in restricting particular mRNAs to the neuronal cell body.