Leukemogenic Mechanism by genomic mutations of hematopoietic-speci is transcription factor, AML1/RUNX1

造血特异性基因组突变导致的白血病机制是转录因子 AML1/RUNX1

基本信息

批准号：
18591078
负责人：
OKUDA Tsukasa
金额：
$ 2.57万
依托单位：
Kyoto Prefectural University of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18591078/
关键词：
cancer leukemia genome-modified mouse transcription factor RUNX1 AML1 retrovirus

项目摘要

Hematopoietic transcription factor AML1 (RUNX1) is a frequent target of leukemia-associated chromosome translocations. AML1 is rearranged by chromosome translocations to form chimera protein which acts as a strong trans-dominant inhibitor against wild-type AML1 and contributes to leukemia development, while mis-sense mutations at DNA-contacting residues of the molecule have also been recognized as leukemia-associated mutations recently. In this study we assessed the consequences of these point mutations in context of entire animal. We successfully introduced each of the mutations, R139Q, R174Q, R177Q, or I150ins, into mouse germline through the knock-in approach. All mouse lines were embryonic lethal when inherited homozygously, indicating that these alleles are all loss-of-function type mutations. In contrast, heterozygotes for each mutation were normally born and developed healthy. They were fertile and developed no overt leukemia through their lives. Thus, these mutations seem to be insufficient to cause clinical leukemia as single allele, showing sharp contrast to the case for human diseases. Thus, it was suggested that additional co-operative mutation (s) are required to develop the disease. In order to address this issue, we performed retroviral-infection experiment using R174Q mice, and found that heterozygotes had tendency to develop leukemia earlier than their wild-type littermates did. This observation indicates that one allele mutation of AML1 serves to promote leukemia-onset one step further. In addition, cloning-analysis for proviral integration sites within the leukemia genome revealed a number of candidate co-operative genes. We are currently analyzing these gene products to see if they collaborate in human diseases.

造血转录因子 AML1 (RUNX1) 是白血病相关染色体易位的常见靶标。 AML1 通过染色体易位重排形成嵌合蛋白，该蛋白作为野生型 AML1 的强反式显性抑制剂，有助于白血病的发展，而该分子 DNA 接触残基的错义突变也被认为是白血病的致病因素。最近发生了相关突变。在这项研究中，我们评估了这些点突变对整个动物的影响。我们通过敲入方法成功地将每个突变 R139Q、R174Q、R177Q 或 I150ins 引入小鼠种系中。所有小鼠系在纯合遗传时都是胚胎致死的，表明这些等位基因都是功能丧失型突变。相比之下，每种突变的杂合子都正常出生并健康发育。他们具有生育能力，一生中没有患上明显的白血病。因此，这些突变似乎不足以作为单一等位基因引起临床白血病，与人类疾病的情况形成鲜明对比。因此，有人建议需要额外的协同突变来发展该疾病。为了解决这个问题，我们用R174Q小鼠进行了逆转录病毒感染实验，发现杂合子比野生型同窝小鼠更容易患上白血病。这一观察结果表明，AML1 的一个等位基因突变进一步促进了白血病的发病。此外，对白血病基因组内原病毒整合位点的克隆分析揭示了许多候选协同基因。我们目前正在分析这些基因产物，看看它们是否在人类疾病中发挥作用。