Small RNAs in Stem Cell Differentiation and Neural Development

描述（由申请人提供）：了解指导干细胞分化的调控网络对于实现干细胞治疗的前景至关重要。分化需要细胞的mRNA和蛋白质组成发生大而快速的变化。小RNA特别适合执行这项任务。例如，微小RNA，小RNA的一个亚类，被预测同时单独调控数百个靶基因。该提案的总体目标是系统地研究小RNA在胚胎和神经干细胞分化中的作用。这是一项合作资助，包括干细胞和小RNA专家。为了解决赠款的总体目标，开发了一种小鼠胚胎干细胞模型，该模型特异性地敲除microRNA功能，从而分离了两种主要类型的小RNA，microRNA和siRNA在哺乳动物发育中的作用。该模型基于RNA结合蛋白DGCR 8的条件性缺失，该蛋白是加工pri-to pre-microRNA所需的。该基金的具体目标包括：1）基于DGCR 8缺失ES细胞在细胞周期G1期积累的初步结果，分析microRNA在干细胞增殖中的作用，2）基于DGCR 8缺失ES细胞即使在严格的分化条件下也能持续自我更新的初步发现，表征miRNAs在干细胞分化中的作用。3)鉴定干细胞功能所需的新型非microRNA小RNA。该目的是基于DGCR 8无效ES细胞表型不同于Dicer无效表型的发现。这个项目的完成将有助于确定调控网络，可以操纵分化和潜在的去分化细胞沿着特定的发展途径。小RNA是一类相对较新的细胞调节因子，其对基因功能的普遍性和全局性影响表明它们在正常和异常的人类发育中起着核心作用。最近的证据表明，它们在肿瘤的发展中起着重要作用。因此，系统分析它们在胚胎和体干细胞中的功能，如本研究所提出的，应该为它们如何影响和可用于诊断和治疗人类疾病提供重要的见解。

DESCRIPTION (provided by applicant): Understanding the regulatory networks that direct stem cell differentiation is critical to realizing the promise of stem cell therapy. Differentiation requires large and rapid shifts in the mRNA and protein constitution of cells. Small RNAs are particularly well suited to perform this task. For example, microRNAs, a subclass of small RNAs, are predicted to individually regulate hundreds of target genes simultaneously. The overall goal of this proposal is to systematically study the role of small RNAs in embryonic and neural stem cell differentiation. This is a collaborative grant including experts in stem cells and small RNAs. To address the overall objective of the grant, a mouse embryonic stem cell model was developed that specifically knocks-out microRNA function thereby separating the roles of the two main classes of small RNAs, microRNAs and siRNAs, in mammalian development. This model is based on the conditional deletion of the RNA binding protein DGCR8, which is required for the processing of pri- to pre-microRNAs. The specific aims of this grant include: 1) the analysis of role of microRNAs in stem cell proliferation based on preliminary results showing that DGCR8 null ES cells accumulate in the G1 phase of the cell cycle, 2) characterization of the role of miRNAs in stem cell differentiation based on initial findings that DGCR8 null ES cells continue to self-renew even under strict differentiation conditions. 3) identification of novel non-microRNA small RNAs that are required for stem cell function. This aim is based on the finding that the DGCR8 null ES cell phenotype differs from that of the Dicer null phenotype. Completion of this project will help identify regulatory networks that can be manipulated to differentiate and potentially de-differentiate cells along specific developmental pathways. Small RNAs are a relatively new class of cell regulators whose pervasiveness and global effects on gene function suggests they have a central role in both normal and abnormal human development. In support of this, recent evidence shows they have an important role in the development of tumors. Therefore, a systematic analysis of their function in embryonic and somatic stem cells as proposed in this grant should provide important insights into how they influence and can be used to diagnose and treat human disease.