Genetic analysis of a microRNA pathway regulating neural tube closure

 描述(由申请人提供)：本提案的总体目标是建立一种新的机制，通过该机制，microRNA(MiRNA)miR-302/367调节神经管关闭(NTC)。NTC的中断会导致神经管缺陷(NTD)，这是人类第二常见的出生缺陷，影响1到1000名新生儿。然而，在转录后基因调控水平上控制NTC的调节器和机制在很大程度上仍不清楚。我们已经建立了第一个NTD的miRNA小鼠模型。我们发现miR-302/367缺失会导致NTD和胚胎死亡。神经前体细胞在突变的胚胎中表现出增殖减少、过早分化和存活率降低的现象。重要的是，我们已经确定了在突变胚胎中受到影响的特定细胞行为中具有潜在作用的单个miRNA靶标。此外，我们发现miR-302/367与调节基因表达的RNA结合蛋白Lin41相关；Lin41的缺失也会导致NTD。这些初步数据导致了一个新的假设，即miR-302/367与Lin41相互作用，通过在神经管关闭(NTC)过程中调节不同的miRNA靶点来协调控制多个神经前体细胞(NPC)的行为。在本项目中，我们将确定miR-302/367在神经管关闭过程中的功能及其作用机制。我们将追求三个具体目标：1)确定miR-302/367突变小鼠神经管缺陷(NTD)的发育和细胞学基础；2)测试我们已确定的miR-302靶基因是否在神经管关闭过程中调节特定的细胞行为；3)测试miR-302与Lin41一起在神经管关闭过程中调节基因表达和NPC行为的假设。总之，这些研究将提高我们对与NTD相关的遗传因素的理解，并为神经管闭合和神经管缺陷(NTD)的机制提供新的见解。

 DESCRIPTION (provided by applicant): The overall goal of this proposal is to establish a novel mechanism whereby microRNA (miRNA) miR-302/367 regulates neural tube closure (NTC). Disruption of NTC leads to neural tube defect (NTD), which is the second most common birth defect in humans affecting 1 to 1,000 births. However, the regulators and mechanisms that control NTC at post-transcriptional gene regulation levels remain largely unknown. We have created the first miRNA mouse model of NTD. We found that depletion of miR-302/367 leads to NTD and embryonic lethality. Neural precursor cells (NPCs) exhibit reduced proliferation, premature differentiation, and decreased survival in the mutant embryos. Importantly, we have identified individual miRNA targets with potent roles in specific cellular behaviors that are affected in mutant embryos. In addition, we found that miR-302/367 is associated with an RNA binding protein Lin41 to regulate gene expression; depletion of Lin41 also leads to NTD. These preliminary data lead to a novel hypothesis that miR-302/367 interacts with Lin41 to coordinately control multiple neural precursor cell (NPC) behaviors by regulating different miRNA targets during neural tube closure (NTC). In this project, we will determine miR-302/367 functions and their action mechanisms during neural tube closure. Three specific aims will be pursued: 1) Determine the developmental and cellular basis of neural tube defect (NTD) in miR-302/367 mutant mice; 2) Test whether individual genes that we have identified as targets of miR-302 mediate specific cellular behaviors during neural tube closure; 3) Test the hypothesis that miR-302 functions together with Lin41 to regulate gene expression and NPC behaviors during neural tube closure. Together, these studies will improve our understanding of genetic factors associated with NTD and provide novel insights into mechanisms underlying neural tube closure and neural tube defect (NTD).