Systematic investigation of microRNA function in developing neurons

正常的大脑功能关键依赖于调节基因表达的生物网络的完整性。最近在对蠕虫的研究中发现，microRNAs构成了一类新的关键调控因子，在细胞转录后水平上调节基因表达。对缺乏所有microRNAs的动物模型的研究表明，它们对生命和大脑的正常发育都是必不可少的。目前，诸如microRNAs如何相互作用以及它们如何在全球范围内牵涉到神经生物学等基本问题仍然没有答案。此外，与神经元发育有关的microRNAs(及其调控基因)的数量和身份尚不清楚，特别是在哺乳动物系统中。在目前的项目中，我们希望利用定义良好的初级海马神经元系统来解决这些问题。由于几乎所有培养的细胞都遵循脑中所见的不同分化步骤，从神经元圆形前体细胞到具有明确轴突和树突亚域和突触活性的完全极化的神经元，因此有可能以定量和定性的方式跟踪基因表达的逐渐变化。我们建议首先在全球水平上研究microRNAs在调节神经元表型中的作用，然后再单独研究。这些实验将首次系统地研究microRNAs如何导致神经元网络的复杂性。

Normal brain function critically depends on the integrity of biological networks that regulate the expression of genes. Discovered recently from studies in worms, microRNAs constitute a novel class of key regulators of gene expression regulation at the posttranscriptional level in the cell. Studies in animal models lacking all microRNAs have shown that they are essential for life as well as proper brain development. At this moment, fundamental questions such as how microRNAs interact and how they are globally implicated in neurobiology remain unanswered. Furthermore, the number and identity of microRNAs (and genes they regulate) implicated in neuronal development, particularly in a mammalian system, are unknown. In the current project we want to make use of the very well defined primary hippocampal neuron system to address these questions. As almost all the cells in culture follow in a synchronized way the different differentiation steps as seen in brain, from a neuronal round precursor cell towards fully polarized neurons with clear axon and dendritic subdomains and synaptic activity, it is possible to follow in a quantitative and qualitative way gradual changes in gene expression. We propose to investigate the role of microRNAs, first at a global level and then individually, in modulating the neuronal phenotype. These experiments will allow a first systematic investigation of how microRNAs contribute to the complexity of the neuronal network.