DIFFERENTIAL MESSENGER-RNA TRANSPORT AND THE REGULATION OF PROTEIN-SYNTHESIS - SELECTIVE SENSITIVITY OF PURKINJE-CELL DENDRITIC MESSENGER-RNAS TO TRANSLATIONAL INHIBITION

Although the majority of mRNAs expressed in neurons are confined to th e perikaryon, a growing number appear to be transported into dendrites . It is likely that this allows for the local regulation of protein sy nthesis within discrete subcellular compartments. Here, three differen t subcellular distribution patterns are demonstrated for four mRNAs th at encode proteins highly expressed in Purkinje cells and their dendri tes; mRNAs are found in the perikaryon only, perikaryon and proximal d endrite, or perikaryon and proximal plus distal dendrites. Further, it is shown that transport of an mRNA into the dendrites increases its s ensitivity to translational inhibition by diphtheria toxin. These data suggest a simple model whereby the transport machinery can regulate t he translation of selected mRNAs. Thus, environmental signals that gen erally affect translational efficiency in concert with the selectivity provided by the transport machinery could provide a means to locally regulate the synthesis of a restricted pool of proteins.