MicroRNAs' Role in Hematopoietic Lineage Differentiation

描述(申请人提供)：最近发现的microRNAs(MiRNAs)、RNA干扰、短干扰RNAs和小调节RNAs揭示了在动植物发育中由短RNAs介导的潜在的广泛的基因调控机制。MiRNAs是一类丰富的~22nT内源性非编码RNA。一些基因已被证明通过在转录后水平上控制基因表达而在植物和动物的发育中发挥重要作用。最近发现miR-181在体外和体内均能促进B细胞分化，首次证明miRNAs在脊椎动物发育中具有调控作用(Chen等，Science，2004,303：83)。然而，miRNAs在脊椎动物发育中发挥作用的例子仍然很少，而且miRNAs发挥其功能的分子机制在很大程度上还不清楚。这项研究计划解决了这些基本问题，并旨在建立miRNA介导的转录后基因调控电路在造血过程中潜在的广泛影响。通过miRNA克隆和表达分析，我们已经鉴定出一组可能在谱系分化中发挥重要作用的造血miRNAs。我们将试图确定这些miRNAs在造血谱系分化的各个方面的功能，以便我们能够确定miRNAs在造血中的更广泛作用(目标1)。通过体外和体内分化实验，我们将能够剖析受miRNAs调控的潜在信号通路，确定miRNA基因的结构和功能关系，定义miRNAs作用的祖细胞群(S)，并描述由miRNAs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确定造血miRNAs的功能相关的目标基因(目标3)。了解miRNAs在造血中的生物学功能将有助于阐明miRNAs在血液病中的作用，并可能导致纠正包括白血病在内的许多血液病的新的治疗策略。这项拟议的研究还将为那些寻求将miRNAs植入其他生物过程的人提供方法、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.