Runx1 Binding Sites as Scaffolds That Mediate Chromosome Translocation

人类急性和慢性白血病的一个显著特征是发现它们是由 非随机的体细胞获得性染色体易位。我们研究的长期目标是 确定染色体易位的产生是否有共同的机制。作为一名 生物模型，我们使用的是RUNX1基因，它编码一种重要的造血转录 是急性髓系白血病(AMI)最常见的染色体易位靶点。这个 RUNX1基因位于21号染色体上，有趣的是，与(8；21)和(16；21)AML相关的 易位，所有的基因组断裂点都在内含子5中被发现。因此，一个关键的问题是什么是 使RUNX1基因参与染色体易位的因素？我们的工作 假设存在于断点区的染色质结构是t(8；21)的决定因素。 易位。此外，我们假设基因的亚核定位可能是决定性的。 对dsDNA断裂的易感性和易位时伴侣基因的选择 是生成的。染色质与细胞核结构特征的详细比较 定位RUNX1、ETO和重组的AML/ETO基因座将使我们能够识别 可以解释在断点区域观察到的可访问性增加的共同特征。这个 根据我们的初步数据提出的实验将结合合作的专业知识 实验室研究可作为RUNX1基因座决定因素的顺式和反式作用因素 重组频率。母基金的重点是染色质之间的相互关系。 组织、RUNX因子的核区划和基因表达。在FIRCA的这份提案中， 我们扩大了这些研究的范围，以解决RUNX调控因素、核 定位和对染色体易位的易感性。这项研究将主要在智利进行，时间为 康塞普西翁大学与索拉亚·古铁雷斯合作，作为NIH赠款5P01的延伸 AR48818，项目。

A striking characteristic of the human acute and chronic leukemias is the finding that they are the result of nonrandom, somatically acquired chromosomal translocations. The long-term goal of our research is to determine if there is a common mechanism involved in the generation of chromosomal translocations. As a biological model, we are using the RUNX1 gene, which encodes an important hematopoietic transcription factor and is the most frequent target of chromosomal translocations in acute myeloid leukemia (AMI). The RUNX1 gene is located on chromosome 21, and interestingly, for both the (8; 21) and (16; 21) AML-related translocations, all the genomic breakpoints are found in intron 5. Therefore, a key question is what are the factors that predispose the RUNX1 gene to be involved in chromosomal translocations? Our working hypothesis is that the chromatin structure present at the breakpoint regions is determinant for the t(8;21) translocation. Moreover, we hypothesize that the sub-nuclear localization of a gene may be determinant both of the gene susceptibility to dsDNA breaks and in the selection of the partner gene when a translocation is generated. A detailed comparison between the structural characteristics of chromatin and the nuclear positioning of the RUNX1, ETO and the recombinant AML/ETO locus will allow us to identify the presence of common features that may account for the increased accessibility observed at the breakpoint regions. The proposed experiments based on our preliminary data will combine the expertise of the collaborating laboratories to investigate the cis and trans acting factors that can be determinants of the RUNX1 locus recombination frequency. The focus of the parent grant is the interrelationship between chromatin organization, nuclear compartmentalization of Runx factors, and gene expression. In this FIRCA proposal, we extend the scope of these studies to address the relationship between Runx regulatory factors, nuclear localization, and susceptibility to chromosomal translocations. This research will be done primarily in Chile at the Universidad de Concepcion in collaboration with Soraya Gutierrez, as an extension of NIH grant 5P01 AR48818, projects.