Localization of FMRP-associated mRNA granules and requirement of microtubules for activity-dependent trafficking in hippocampal neurons
Localization of FMRP-associated mRNA granules and requirement of microtubules for activity-dependent trafficking in hippocampal neurons
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DOI：
10.1111/j.1601-183x.2005.00128.x
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发表时间：
2005-08-01
影响因子：
2.5
通讯作者：
Basselll, GJ
中科院分区：
文献类型：
--
作者：
Antar, LN;Dictenberg, JB;Basselll, GJ
脆性X综合征是由脆性X智力迟钝蛋白（FMRP）的缺失引起的，FMRP是一种mRNA结合蛋白，其可能在调节树突mRNA定位和/或突触蛋白合成中起重要作用。我们最近应用高分辨率荧光成像方法来记录FMRP颗粒在培养的海马神经元树突和棘中的存在、运动性和活性依赖性调节。在这项研究中，我们表明，FMRP颗粒分布到富F-肌动蛋白的车厢，包括丝状伪足，棘和生长锥在海马神经元的阶段性发展的文化。脆性X智力低下蛋白颗粒与核糖体、核糖体RNA和MAP 1B mRNA共定位，MAP 1B mRNA是一种已知的FMRP靶点，编码一种对微管和肌动蛋白稳定很重要的蛋白。树突内的FMRP水平减少破坏微管动力学，但不破坏F-肌动蛋白。FMRP运输动力学的直接测量使用荧光恢复后，在活的神经元中的光漂白表明，微管诱导mGluR依赖的易位到树突。这项研究提供了进一步的表征的组成和调控运输的FMRP颗粒在树突的海马神经元。
Fragile X syndrome is caused by the absence of the fragile X mental-retardation protein (FMRP), an mRNA-binding protein, which may play important roles in the regulation of dendritic mRNA localization and/or synaptic protein synthesis. We have recently applied high-resolution fluorescence imaging methods to document the presence, motility and activity-dependent regulation of FMRP granule trafficking in dendrites and spines of cultured hippocampal neurons. In this study, we show that FMRP granules distribute to F-actin-rich compartments, including filopodia, spines and growth cones during the staged development of hippocampal neurons in culture. Fragile X mental-retardation protein granules were shown to colocalize with ribosomes, ribosomal RNA and MAP1B mRNA, a known FMRP target, which encodes a protein important for microtubule and actin stabilization. The levels of FMRP within dendrites were reduced by disruption of microtubule dynamics, but not by disruption of F-actin. Direct measurements of FMRP transport kinetics using fluorescence recovery after photobleaching in living neurons showed that microtubules were required to induce the mGluR-dependent translocation into dendrites. This study provides further characterization of the composition and regulated trafficking of FMRP granules in dendrites of hippocampal neurons.