Post-transcriptional RNA regulation in mammalian neural stem cells

摘要 这个R21建议的目标是揭示神经祖细胞重要的转录后机制 通过关注RNA结合蛋白Rbm 8a，RBM 8A拷贝数变异是 与智力残疾、自闭症、小头症和大头症有关。RBM 8A突变导致TAR 综合征，一种罕见的血液和骨骼疾病，也可以表现为神经发育缺陷。这些 神经发育病理学可由大脑皮层的异常神经发生引起，其中神经元 是由增殖的神经祖细胞产生的实际上，我们的实验室已经发现神经祖细胞- 小鼠中特异性Rbm 8a单倍不足破坏了祖细胞功能和神经发生，最终 导致小头畸形。Rbm 8a与Magoh和Eif 4a 3一起形成外显子连接复合物，其结合 剪接的mRNA介导mRNA代谢的关键方面，包括翻译。这些发现 Rbm 8a可能通过破坏神经发生来影响疾病。然而，我们对 Rbm 8a影响大脑发育的分子机制仅限于少数候选者。在这 建议，我们将测试中心假设，Rbm 8a结合并促进转录本的翻译 与神经祖细胞增殖有关。首先，我们将确定Rbm 8a在神经上皮细胞中的直接靶点。 祖细胞，使用一种新的RNA免疫沉淀为基础的方法在体内。其次，我们将使用生物化学 发现神经上皮祖细胞中Rbm 8a翻译靶点的方法。我们的建议是建立在 强有力的初步数据，包括发现Rbm 8a单倍体的全转录组变化， 神经上皮祖细胞。成功完成，这些目标将提供新的见解如何神经 在正常和病理情况下，祖细胞调节发育中的脑中的命运决定。 由于RBM 8A突变与神经发育障碍有关，这些研究有望提供 重要的分子见解如何在这个基因的突变影响疾病的病理。

ABSTRACT This goal of this R21 proposal is to uncover post-transcriptional mechanisms important for neural progenitors of the developing brain, by focusing on the RNA binding protein, Rbm8a. RBM8A copy number variations are associated with intellectual disability, autism, microcephaly and macrocephaly. RBM8A mutations cause TAR syndrome, a rare blood and bone disorder which can also present with neurodevelopmental deficits. These neurodevelopmental pathologies can arise from aberrant neurogenesis of the cerebral cortex, in which neurons are produced from proliferating neural progenitors. Indeed, our lab has discovered that neural progenitor- specific Rbm8a haploinsufficiency in mice disrupts progenitor function and neurogenesis, which ultimately causes microcephaly. Rbm8a, together with Magoh and Eif4a3, form the exon junction complex, which binds spliced mRNAs to mediate key aspects of mRNA metabolism including translation. Together these findings demonstrate Rbm8a may influence disease by disrupting neurogenesis. However, our understanding of molecular mechanisms by which Rbm8a impacts brain development is limited to just a few candidates. In this proposal, we will test the central hypothesis that Rbm8a binds to and promotes translation of transcripts relevant for neural progenitor proliferation. First we will identify direct targets of Rbm8a in neuroepithelial progenitors, using a novel RNA immunoprecipitation-based approach in vivo. Second, we will use biochemical approaches to discover Rbm8a translational targets in neuroepithelial progenitors. Our proposal is built upon strong preliminary data, including the discovery of transcriptome-wide changes in Rbm8a hapoloinsufficient neuroepithelial progenitors. Successfully completed, these aims will provide new insights into how neural progenitors regulate fate decisions in the developing brain under both normal and pathological settings. Because RBM8A mutation is associated with neurodevelopmental disorders, these studies promise to provide important molecular insights into how mutations in this gene influence disease pathology.