EZH2 in lymphoid lineage specification and commitment

描述（由申请人提供）：EZH2是多梳阻遏物复合物2（PRC2）的组蛋白甲基转移酶组分，其是发育期间抑制多种谱系特异性转录因子所必需的。最近的研究表明，EZH2功能的获得和丧失都可能导致淋巴恶性肿瘤。在这里，我们将检验EZH2是普通淋巴祖细胞向适应性淋巴细胞（B和T细胞）命运而不是先天淋巴细胞（ILC1和ILC2）命运定型所必需的假设。我们将测试这一假设，通过检查Ezh2失活的后果，在竞争性和非竞争性条件下，通过流式细胞术分析的淋巴样细胞，并通过使用在体外测定，测量的分化和承诺的频率，以一个给定的谱系在共同的淋巴祖细胞。与此同时，我们将通过检查由EZH2缺陷引起的淋巴细胞及其祖细胞中基因表达的总体变化来鉴定EZH2靶基因，以及鉴定在EZH2缺陷细胞中被EZH2结合且未能经历H3K27三甲基化（EZH2活性的标志）的基因。总之，我们的研究将提供显着的洞察机制控制基因表达在淋巴细胞谱系规范和承诺。此外，我们将更好地了解EZH2突变如何导致白血病和淋巴瘤，以及EZH2抑制剂治疗这些疾病如何影响正常的淋巴细胞发育。

DESCRIPTION (provided by applicant): EZH2 is the histone methyltransferase component of the polycomb repressor complex 2 (PRC2), which is required for repression of numerous lineage specifying transcription factors during development. Recent studies have revealed that both gain and loss of function of EZH2 can contribute to lymphoid malignancy. Here we will test the hypothesis that EZH2 is required for commitment of common lymphoid progenitors to the adaptive lymphocyte (B and T cell) fates but not to innate lymphocyte (ILC1 and ILC2) fates. We will test this hypothesis by examining the consequences of Ezh2 inactivation in common lymphoid progenitors under competitive and non-competitive conditions by flow cytometric analysis of lymphoid cells and through the use of in vitro assays that measure both frequency of differentiation and commitment to a given lineage. In parallel we will identify EZH2 target genes by examining the global changes in gene expression in lymphocytes and their progenitors caused by EZH2-deficiency as well as identifying genes that are bound by EZH2 and fail to undergo H3K27 trimethylation, the hallmark of EZH2 activity, in EZH2-deficient cells. Taken together, our study will provide significant insight into the mechanisms controlling gene expression during lymphocyte lineage specification and commitment. In addition, we will gain a better understanding of how EZH2 mutations lead to leukemia and lymphoma and how treatment of these diseases with EZH2 inhibitors might influence normal lymphocyte development.