T(8;21) in Blood Cell Proliferation and Differentiation

描述(申请人提供)：t(8；21)是急性髓系白血病最常见的遗传异常之一，占所有病例的15%。这种易位产生了融合蛋白AML1-ETO，它包含AML1蛋白的N端区域，包括矮小DNA结合域，以及几乎整个ETO蛋白的C末端区域。这一建议检验了这样的假设，即t(8；21)融合蛋白AML1-ETO需要额外的突变才能导致白血病，并旨在确定与额外突变相关的分子途径。对AML1基因敲除小鼠的研究表明，AML1在造血过程中起着关键作用。我们对AML1-ETO敲入小鼠的分析表明，AML1-ETO在早期造血细胞承诺中主要阻断AML1的功能。此外，我们的数据表明AML1-ETO的表达不足以引起白血病。在特殊目的#1中提出的研究将使用AML1-ETO敲除AML1基因的ES细胞来研究AML1-ETO对造血细胞承诺的影响。在特殊目的#2中提出的研究将利用基因工程小鼠研究性染色体在t(8；21)相关急性髓系白血病的发展中的作用。在特殊目的#3中提出的研究将在转基因小鼠中调查与t(8；21)相关的急性髓系白血病发生相关的额外基因的异常表达或突变。我们已经建立了AML1-ETO的诱导表达或髓系特异性表达的动物模型。提出的实验将解决关于正常血细胞分化的关键因素以及t(8；21)如何与白血病的发展有关的基本问题。

DESCRIPTION (provided by applicant): The t(8;21) is one of the most common genetic abnormalities in acute myeloid leukemia, identified in 15% of all cases. This translocation generates the fusion protein, AML1-ETO, which contains the N-terminal region of the AML1 protein, including the runt DNA binding domain, and almost the entire ETO protein at the C terminal region. This proposal tests the hypothesis that the t(8;21) fusion protein AML1-ETO requires additional mutations for leukemogenesis and aims to identify molecular pathways associated with the additional mutation. Study of AML1 knockout mice demonstrates that AML1 plays a critical role during hematopoiesis. Our analysis with AML1-ETO knock-in mice shows that AML1-ETO dominantly blocks AML1 function during early hematopoietic cell commitment. Furthermore, our data suggest that AML1-ETO expression is not sufficient to cause leukemia. The studies proposed in Specific Aim #1 will investigate the effect of AML1-ETO on hematopoietic cell commitment using ES cells with AML1-ETO knocked into the AML1 locus. The studies proposed in Specific Aim #2 will study the involvement of sex chromosomes in the development of t(8;21) associated acute myeloid leukemia using genetically engineered mice. The studies proposed in Specific Aim #3 will investigate the abnormal expression or the mutation of additional genes associated with the development of t(8;21) involved acute myeloid leukemia in transgenic mice. We have established animal models with either inducible or myeloid specific expression of AML1-ETO. The experiments proposed will address fundamental questions about the factors critical for normal blood cell differentiation and how t(8;21) is related to the development of leukemia.