MicroRNAs' Role in Hematopoietic Lineage Differentiation

描述（由申请人提供）：最近发现的microRNAs （miRNAs）、RNA干扰、短干扰RNA和小调节RNA揭示了短RNA在动植物发育中介导的潜在广泛的基因调控机制。mirna是一类丰富的~ 22nt内源性非编码rna。一些已被证明在植物和动物的发育中通过控制转录后水平的基因表达发挥重要作用。最近有研究表明，miR-181可以促进体外和体内的b细胞分化，首次证明mirna在脊椎动物发育中具有调节作用（Chen et al., Science, 2004,303:83）。然而，mirna在脊椎动物发育中发挥作用的例子仍然很少，mirna发挥其功能的分子机制在很大程度上是不清楚的。本研究计划解决这些基本问题，旨在确定mirna介导的转录后基因调控回路在造血过程中的潜在广泛影响。通过miRNA的克隆和表达分析，我们已经鉴定出一组造血miRNA可能在谱系分化中发挥重要作用。我们将尝试定义这些mirna在造血谱系分化的各个方面的功能，以便我们可以确定mirna在造血中的更广泛作用（目的1）。通过明确的体外和体内分化分析，我们将能够剖析受miRNA调控的潜在信号通路，确定miRNA基因的结构和功能关系，确定miRNA作用的祖细胞群，并描述由miRNA控制的细胞过程（目标2）。最后，我们将结合计算和实验方法来鉴定造血mirna的功能相关靶基因（目的3）。了解mirna在造血中的生物学功能将揭示mirna在血液系统疾病中的作用，并可能导致新的治疗策略来纠正许多血液系统疾病，包括白血病。拟议的研究还将为那些寻求将mirna置于其他生物过程中的人提供方法、见解和灵感。

DESCRIPTION (provided by applicant): The recent discoveries of microRNAs (miRNAs), RNA interference, short interfering RNAs, and small modulatory RNAs have revealed potentially widespread gene regulatory mechanisms that are mediated by short RNAs in animal and plant development. miRNAs are an abundant class of~22 nt endogenous noncoding RNAs. Some have been shown to play an important role in plant and animal development by controlling gene expression at the posttranscriptional level. Recently it was demonstrated that miR-181 could promote B-cell differentiation in vitro and in vivo, providing the first evidence that miRNAs have regulatory roles in vertebrate development (Chen et al., Science, 2004, 303:83). However, examples of miRNAs functioning in vertebrate development are still rare, and the molecular mechanisms through which miRNAs exert their functions are largely unclear. This research proposal addresses these fundamental questions and aims to establish the potential widespread influences of miRNA-mediated posttranscriptional gene regulatory circuitries during hematopoiesis. Through miRNA cloning and expression analyses, we have identified a set of hematopoietic miRNAs that may play important roles in lineage differentiation. We will try to define the functions of these miRNAs in various aspects of hematopoietic lineage differentiation so that we can establish broader roles for miRNAs in hematopoiesis (aim 1). With defined in vitro and in vivo differentiation assays we will be able to dissect the potential signaling pathways that are regulated by miRNAs, determine the structural and functional relationships of miRNA genes, define the progenitor cell population(s) that miRNAs act on, and delineate the cellular processes controlled by miRNAs (aim 2). Finally, we will combine computational and experimental approaches to identify the functionally relevant target genes of hematopoietic miRNAs (aim 3). Understanding the biological functions of miRNAs in hematopoiesis will shed light on the roles of miRNAs in hematological disorders and could lead to novel therapeutic strategies to correct many hematological disorders, including leukemias. The proposed research will also provide methods, insights, and inspiration to those seeking to place miRNAs into other biological processes.