Steward O, Wallace C S, Lyford G L, Worley P F
Department of Neuroscience, University of Virginia, Charlottesville 22908, USA.
Neuron. 1998 Oct;21(4):741-51. doi: 10.1016/s0896-6273(00)80591-7.
Polyribosomal complexes beneath postsynaptic sites on dendrites provide a substrate for local translation of particular mRNAs, but the signals that target mRNAs to synapses remain to be defined. Here, we report that high frequency activation of the perforant path projections to the dentate gyrus causes newly synthesized mRNA for the immediate-early gene (IEG) Arc to localize selectively in activated dendritic segments. Newly synthesized Arc protein also accumulates in the portion of the dendrite that had been synaptically activated. The targeting of Arc mRNA was not disrupted by locally inhibiting protein synthesis, indicating that the signals for mRNA localization reside in the mRNA itself. This novel mechanism through which newly synthesized mRNA is precisely targeted to activated synapses is well suited to play a role in the enduring forms of activity-dependent synaptic modification that require protein synthesis.
树突上突触后位点下方的多核糖体复合物为特定mRNA的局部翻译提供了一个底物，但将mRNA靶向突触的信号仍有待确定。在这里，我们报告称，对齿状回的穿通通路投射进行高频激活会导致立即早期基因（IEG）Arc的新合成mRNA选择性地定位于激活的树突段中。新合成的Arc蛋白也会在已被突触激活的树突部分积累。局部抑制蛋白质合成不会破坏Arc mRNA的靶向，这表明mRNA定位信号存在于mRNA本身。这种新合成的mRNA精确靶向激活突触的新机制非常适合在需要蛋白质合成的活动依赖性突触修饰的持久形式中发挥作用。
