Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom.
J Neurosci. 2013 Jun 19;33(25):10384-95. doi: 10.1523/JNEUROSCI.5858-12.2013.
The RNA-binding protein Hermes [RNA-binding protein with multiple splicing (RBPMS)] is expressed exclusively in retinal ganglion cells (RGCs) in the CNS, but its function in these cells is not known. Here we show that Hermes protein translocates in granules from RGC bodies down the growing axons. Hermes loss of function in both Xenopus laevis and zebrafish embryos leads to a significant reduction in retinal axon arbor complexity in the optic tectum, and expression of a dominant acting mutant Hermes protein, defective in RNA-granule localization, causes similar defects in arborization. Time-lapse analysis of branch dynamics reveals that the decrease in arbor complexity is caused by a reduction in new branches rather than a decrease in branch stability. Surprisingly, Hermes depletion also leads to enhanced early visual behavior and an increase in the density of presynaptic puncta, suggesting that reduced arborization is accompanied by increased synaptogenesis to maintain synapse number.
RNA 结合蛋白 Hermes（具有多种剪接功能的 RNA 结合蛋白）仅在中枢神经系统的视网膜神经节细胞 (RGC) 中表达，但它在这些细胞中的功能尚不清楚。在这里，我们表明 Hermes 蛋白从 RGC 体沿着生长的轴突在颗粒中易位。在非洲爪蟾和斑马鱼胚胎中丧失 Hermes 功能会导致视顶盖中视网膜轴突树突复杂性显著降低，并且表达 RNA 颗粒定位缺陷的显性作用突变型 Hermes 蛋白也会导致类似的分支化缺陷。分支动态的时程分析表明，树突复杂性的降低是由于新分支的减少而不是分支稳定性的降低所致。令人惊讶的是，Hermes 耗竭也会导致早期视觉行为增强和突触前突密度增加，这表明减少的树突分支伴随着增加的突触发生以维持突触数量。
