剪接体蛋白U2AF1突变体在小鼠骨髓微环境调控异常及促进血液肿瘤发生中的作用及机制研究

骨髓微环境作为外在因素调控正常造血干细胞的生长发育、分化成熟，微环境调控异常则会引起造血紊乱甚至血液肿瘤的发生。剪接体蛋白U2AF1是选择性剪接的关键分子，其突变体U2AF1S34F可引起细胞内剪接错误从而使细胞功能异常。本项目在白血病患者中发现U2AF1S34F的基础上，以剪接体突变作为研究骨髓微环境促进白血病发生的切入点，探索骨髓基质细胞中的U2AF1S34F是否会引起调控造血的剪接产物异常，进而引起造血调控紊乱及白血病的发生。本项目通过骨髓基质细胞中U2AF1S34F对造血调节作用异常的体外实验研究、Prx1启动子下骨髓间充质干细胞特异表达U2AF1S34F的Knock in小鼠的构建及其造血调控异常研究、U2AF1S34F-MSC Knock in小鼠体内促进白血病发生的二次打击研究，将阐明骨髓基质细胞中剪接体突变在造血调控异常及促进血液肿瘤中发生中的作用，并阐明其分子机制。

As an extrinsic event, bone marrow microenvironment takes an important role in regulating hematopoietic stem cell (HSC) growth, differentiation and self-renewal. Changes in bone marrow microenvironment could initiate unbalance of hematopoisis， as well as hematopoietic malignancies development. As a splicing factor, U2AF1 is a key regulator of mRNA transcripts and protein isoforms. U2AF1 mutant, U2AF1S34F, can cause differential splicing of pre-mRNA, affecting biological pathways and cell functions. Based on our previous study that U2AF1S34F has been found in AML patients, in this project, we select U2AF1S34F in bone marrow stromal cells as the breakthrough point of study on the role of abnormal micronenvironment in leukemogenesis. We propose to determine whether U2AF1 mutations in bone marrow stromal cells could cause abnormal splicing of genes and affecting biological pathways of molecules mediated interaction of bone marrow microenvironment and HSC, and further promote leukemogenisis. Via in vitro study of U2AF1S34F mediated abnormal interaction of stroma cells with HSC and construction of U2AF1S34F knock in mice, in which U2AF1S34F specifically expressed in MSC under Prx1 promoter, and investigation of abnormal hematopoisis effects of U2AF1S34F-MSC in U2AF1S34F MSC knock in mice, we would elucidate the contribution of splicing factor mutations of bone marrow stroma cells in abnormal hematopoisis and leukemogenesis, and further define its molecular machanism.