MOUSE MODELS FOR FAMILIAL PLATELET DISORDER

RUNX1基因（也称为AML1）的突变导致一种罕见的家族性血小板疾病，并有发展为急性髓性白血病（FPD/AML）的倾向。FPD/AML患者血小板数量减少，血小板功能缺陷，骨髓和外周血造血祖细胞数量减少。FPD/AML患者也有发展为急性髓性白血病的倾向。在FPD/AML谱系中发现的突变只涉及RUNX1基因的一个拷贝。RUNX1编码异二聚体核心结合因子（CBFs）的一个dna结合亚基。Runx1中的“Runt”结构域介导与非dna结合的CBFbeta亚基的dna结合和异源二聚化。FPD/AML患者的突变包括Runt结构域的错义和无义突变，Runt结构域内隐剪接受体位点的产生，以及基因内缺失。最近在大约25%的M-0 AML患者中也发现了Runx1 Runt结构域的双等位基因点突变，这在该疾病中定义了一个新的亚群。FPD/AML患者相似的临床表型表明，单倍体功能不全是该疾病所有病例的潜在机制。然而，FPD/AML家族中血小板缺陷的严重程度各不相同，这表明微妙的表型差异可能是由不同的FPD/AML RUNX1等位基因赋予的。该项目的目标是了解在FPD/AML和AML M-0患者中发现的Runx1 Runt结构域突变如何在体外和体内影响Runx1蛋白的功能。具体目标是：1。确定在FPD/AML和M-0 AML患者中发现的Runx1 Runt结构域突变如何影响dna结合、CBFP异二聚化和Runt结构域结构。2. 确定在FPD/AML患者中发现的Runx1 Runt结构域的点突变是否导致单倍功能不全、产生部分功能的Runx1等位基因或跨显性阴性Runx1等位基因。3. 生成并表征FPD/AML小鼠模型，模拟造血祖细胞缺陷、血小板缺陷和AML倾向。

Mutations in the RUNX1 gene (also known as AML1) cause a rare familial platelet disorder with propensity to develop acute myelogenous leukemia (FPD/AML). FPD/AML patients have reduced platelet numbers, defects in platelet function, and decreased numbers of hematopoietic progenitors in their bone marrow and peripheral blood. FPD/AML patients also have a propensity to progress to acute myelogenous leukemia. The mutations found in FPD/AML pedigrees involve only one copy of the RUNX1 gene. RUNX1 encodes a DNA-binding subunit of the heterodimeric core-binding factors (CBFs). The "Runt" domain in Runx1 mediates DNA-binding and heterodimerization with the non-DNA-binding CBFbeta subunit. Mutations in FPD/AML patients include missense and nonsense mutations in the Runt domain, creation of a cryptic splice acceptor site within the Runt domain, and an intragenic deletion. Biallelic point mutations in the Runx1 Runt domain were also recently documented in approximately 25% of M-0, AML, defining a new subgroup in this disease. The similar clinical phenotypes of FPD/AML patients suggest that haploinsufficiency is the underlying mechanism in all cases of the disease. However, the severity of platelet defects in FPD/AML families varies, suggesting that subtle phenotypic variation may be conferred by the different FPD/AML RUNX1 alleles. The goals of this project are to understand how mutations found in the Runx1 Runt domain in FPD/AML and AML M-0, patients affect the functions of the Runx1 protein, both in vitro and in vivo. The Specific Aims are: 1. Determine how mutations in the Runx1 Runt domain found in FPD/AML and M-0, AML patients affect DNA-binding, CBFP heterodimerization, and the Runt domain structure. 2. Determine whether point mutations in the Runx1 Runt domain found in FPD/AML patients result in haploinsufficiency, in the generation of partially functional Runx1 alleles, or in transdominant negative Runx1 alleles. 3. Generate and characterize mouse models for FPD/AML that mimic the hematopoietic progenitor defects, platelet defects, and propensity for AML.