Subcellular profiling reveals distinct and developmentally regulated repertoire of growth cone mRNAs.
Subcellular profiling reveals distinct and developmentally regulated repertoire of growth cone mRNAs.
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DOI：
10.1523/jneurosci.1800-10.2010
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发表时间：
2010-11-17
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影响因子：
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通讯作者：
Holt CE
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文献类型：
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作者：
Zivraj KH;Tung YC;Piper M;Gumy L;Fawcett JW;Yeo GS;Holt CE
线索导向的轴突导向部分依赖于生长锥中的局部翻译。已知许多mRNA转录物存在于发育中的轴突中，但对它们的亚细胞分布或特别是哪些转录物存在于生长锥中知之甚少。在这里，激光捕获显微切割（LCM）被用来分离视网膜神经节细胞（RGC）轴突的两种脊椎动物物种，小鼠和非洲爪蟾的生长锥，加上公正的全基因组微阵列分析。一个意想不到的大池的mRNA定义蛋白质合成，氧化磷酸化，癌症，神经疾病和信号转导的主要途径。“年轻”（寻路）与“老”（目标到达）非洲爪蟾生长锥的比较分析显示，转录本的数量和复杂性随着年龄的增长显着增加。许多突触前蛋白质mRNA只存在于旧的生长锥中，这表明功能相关的mRNA组以发育调节的方式靶向生长锥。值得注意的是，一个子集的mRNA是显着丰富的生长锥相比，轴突隔室，表明机制存在本地化的mRNA选择性的生长锥。此外，一些受体转录物（例如，EphB4），只存在于老的生长锥中，在年轻和老的细胞体中同样丰富，表明来自索马的RNA运输是发育调节的。我们的研究结果表明，生长锥中的mRNA库随年龄的变化而动态调节，并表明mRNA定位是定制的，以匹配生长轴突尖端转化为突触前末端的功能需求。
Cue-directed axon guidance depends partly on local translation in growth cones. Many mRNA transcripts are known to reside in developing axons, yet little is known about their subcellular distribution or, specifically, which transcripts are in growth cones. Here laser capture microdissection (LCM) was used to isolate the growth cones of retinal ganglion cell (RGC) axons of two vertebrate species, mouse and Xenopus, coupled with unbiased genomewide microarray profiling. An unexpectedly large pool of mRNAs defined predominant pathways in protein synthesis, oxidative phosphorylation, cancer, neurological disease, and signaling. Comparative profiling of “young” (pathfinding) versus “old” (target-arriving) Xenopus growth cones revealed that the number and complexity of transcripts increases dramatically with age. Many presynaptic protein mRNAs are present exclusively in old growth cones, suggesting that functionally related sets of mRNAs are targeted to growth cones in a developmentally regulated way. Remarkably, a subset of mRNAs was significantly enriched in the growth cone compared with the axon compartment, indicating that mechanisms exist to localize mRNAs selectively to the growth cone. Furthermore, some receptor transcripts (e.g., EphB4), present exclusively in old growth cones, were equally abundant in young and old cell bodies, indicating that RNA trafficking from the soma is developmentally regulated. Our findings show that the mRNA repertoire in growth cones is regulated dynamically with age and suggest that mRNA localization is tailored to match the functional demands of the growing axon tip as it transforms into the presynaptic terminal.