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。分化需要细胞的信使核糖核酸和蛋白质组成发生大而迅速的变化。小RNA特别适合执行这一任务。例如，微小RNA是小RNA的一个子类，据预测，它将分别同时调控数百个靶基因。这项建议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。这是一项合作赠款，包括干细胞和小RNA方面的专家。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，该模型专门敲除了microRNA的功能，从而分离了两类主要的小RNA，即microRNAs和siRNAs，在哺乳动物发育中的作用。这个模型是基于有条件地删除RNA结合蛋白Dgcr8，它是处理Pri-to-Pre-microRNAs所必需的。这项资助的具体目的包括：1)基于初步结果分析microRNAs在干细胞增殖中的作用，初步结果表明Dgcr8缺失的ES细胞在细胞周期的G1期积累，2)基于Dgcr8缺失的ES细胞即使在严格的分化条件下也能继续自我更新的初步发现，鉴定miRNAs在干细胞分化中的作用。3)鉴定干细胞功能所需的新的非microRNA小RNA。这一目的是基于Dgcr8缺失的ES细胞表型不同于Dice缺失的表型的发现。该项目的完成将有助于确定可被操纵的调控网络，以沿着特定的发育途径分化和潜在地去分化细胞。小RNA是一类相对较新的细胞调节因子，其普遍性和对基因功能的全球性影响表明，它们在人类正常和异常发育中都发挥着核心作用。为了支持这一点，最近的证据表明，它们在肿瘤的发展中起着重要作用。因此，按照这项拨款的建议，对它们在胚胎和躯体干细胞中的功能进行系统分析，应该会为它们如何影响和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.