液-液相分離によるニューロンの無中心体性微小管核形成

我们之前的研究强调了微管生成途径的局部放大在神经元分化中的关键作用。微管的生成也会因突触活动和神经元损伤而放大，在神经保护和再生中发挥作用。这就提出了这种放大背后的分子机制是什么的问题。在这个项目中，我们寻找神经元中微管生成的新的非规范过程；我筛选了对乔木发育很重要的未经研究的蛋白质，这些蛋白质通过驱动有丝分裂后微管成核起作用。微管成核活性的实时成像（体内 EB1 成像），确定该过程所需的新因子。通过操纵这个因子，我发现果蝇 c4da 感觉神经元在树突尖端的微管成核显着减少，顺行微管数量显着改变。微管成核的减少在整个微管轴上都很明显，但优先在树突尖端减少。 c4da 神经元生长的实时成像显示，c4da 神经元表现出树干延伸率降低和分支频率降低，导致树突树干发育不良。我在体外进一步研究了这种蛋白质的活性，发现它上调微管成核活性。

Our previous studies emphasize a critical role for local amplification of microtubule generation pathways in differentiating neurons. Microtubule generation is also amplified in response to synaptic activity, and to neuron injury, where it plays a role in neuroprotection and regeneration. This raises the question of what molecular mechanisms underlie this amplification. In this project we looked for a new non-canonical process of microtubule generation in neurons; I have screened through unstudied proteins important for arbor development that act by driving postmitotic microtubule nucleation. Live imaging of microtubule nucleation activity (in vivo EB1 imaging), identifying a new factor required for this process. By manipulation of this factor I show that Drosophila c4da sensory neurons exhibit a dramatic reduction in microtubule nucleation at dendrite tips, with a significant modification in anterograde microtubule numbers. This reduction in microtubule nucleation is apparent across the entire microtubule arbor but is preferentially reduced at the dendrite tips. Live imaging of c4da neuron growth reveal that c4da neurons exhibit reduced arbor extension rate, and reduced branching frequency, leading to a stunted dendritic arbor. I have further investigated the activity of this protein in vitro, finding that it upregulates microtubule nucleation activity.