Post-transcriptional RNA regulation in mammalian neural stem cells

摘要 这项R21提案的目标是揭示对神经前体细胞重要的转录后机制 通过专注于RNA结合蛋白Rbm8a，对发育中的大脑进行研究。RBM8A拷贝数变异有 与智力残疾、自闭症、小头畸形症和巨头畸形有关。RBM8A突变导致TAR 综合症，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 神经发育病理可由大脑皮层异常的神经发生引起，在大脑皮质中，神经元 是由增殖的神经前体细胞产生的。事实上，我们的实验室已经发现神经前体- 小鼠特异性Rbm8a单倍体缺陷会扰乱祖细胞功能和神经发生，最终 导致小头畸形。Rbm8a与Magoh和Eif4a3一起形成外显子连接复合体，结合 剪接的信使核糖核酸调节包括翻译在内的信使核糖核酸代谢的关键方面。综合这些发现 证明Rbm8a可能通过干扰神经发生来影响疾病。然而，我们对此的理解 Rbm8a影响大脑发育的分子机制仅限于几个候选基因。在这 提议，我们将检验Rbm8a结合并促进转录产物翻译的中心假设 与神经前体细胞的增殖有关。首先，我们将在神经上皮细胞中鉴定Rbm8a的直接靶点 祖细胞，使用一种新的基于体内RNA免疫沉淀的方法。第二，我们将使用生化 在神经上皮祖细胞中发现Rbm8a翻译靶点的方法。我们的建议是建立在 强劲的初步数据，包括发现Rbm8a单态不足的转录组范围的变化 神经上皮祖细胞。成功完成，这些目标将提供新的洞察如何神经 在正常和病理环境下，祖细胞在发育中的大脑中调节命运的决定。 由于RBM8A突变与神经发育障碍有关，这些研究有望提供 对该基因突变如何影响疾病病理的重要分子见解。

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.