Involvement of RUNX1 in Megakaryocytic Differentiation

RUNX1 参与巨核细胞分化

• 批准号: 6740878
• 负责人: Adam N. Goldfarb
• 金额: $ 29.64万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-23 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6740878
• 关键词: binding sites; cell differentiation; cell line; clinical research; erythroid stem cell; flow cytometry; gene expression; gene mutation; genetic promoter element; genetic transcription; high performance liquid chromatography; human tissue; immunoprecipitation; megakaryocytes; myeloid stem cell; polymerase chain reaction; protein structure function; tissue /cell culture; transcription factor

DESCRIPTION (provided by applicant): Understanding the transcriptional regulation of megakaryocytic lineage commitment will provide guidance in designing treatments for many bone marrow disorders associated with thrombocytopenia. We have identified the myeloid transcription factor RUNX1 as a protein upregulated early in megakaryocytic differentiation and downregulated early in erythroid differentiation. This expression pattern is unique in that virtually all other megakaryocytic transcription factors, such as GATA-1, FOG-1, NF-E2, and SCL/tal, display shared expression in both megakaryocytic and erythroid lineages. The restricted coexpression of RUNX1 and GATA-1 in megakaryocytes led us to discover that these factors strongly cooperate in the activation of a megakaryocytic promoter. This cooperation depends on RUNX1 binding sites present in the promoter and on the RUNX1 cofactor CBFbeta. Co-immunoprecipitation assays demonstrate physical association of RUNX1/CBFbeta with GATA. This novel functional and physical association correlates with the recent clinical implications of both the GATA-1 and RUNX1 genes in hereditary syndromes with thrombocytopenia. A dominant-negative variant of RUNX1 consists of a fusion with the ETO transcriptional repressor that results from the t(8;21) chromosomal abnormality frequently found in acute myeloid leukemia. We have found that the RUNX1-ETO oncoprotein, in contrast to wild type RUNX1, potently inhibits GATA-1 activation of a megakaryocytic promoter. In addition, RUNX1-ETO demonstrates physical interaction with GATA-1. Thus, one of the oncogenic effects of RUNX1-ETO may consist of blocking GATA driven hematopoietic differentiation. The major aims of this project are: 1) Delineation of the developmental consequences and molecular mechanisms of RUNX1 synergy with GATA-1 in megakaryopoiesis; 2) Determination of the developmental consequences and molecular mechanisms of RUNX1-ETO inhibition of GATA factors.

描述(由申请人提供)：了解巨核细胞谱系承诺的转录调控将为设计治疗与血小板减少相关的许多骨髓疾病提供指导。我们已经确定髓系转录因子RUNX1是一种在巨核细胞分化早期上调、在红系分化早期下调的蛋白质。这种表达模式是独特的，因为几乎所有其他巨核细胞转录因子，如GATA-1、FOG-1、NF-E2和SCL/TAL，在巨核细胞和红系中都显示出共同的表达。RUNX1和GATA-1在巨核细胞中的限制性共表达使我们发现这些因子在巨核细胞启动子的激活中具有很强的协同作用。这种合作依赖于启动子中存在的RUNX1结合位点和RUNX1辅因子CBFbeta。免疫共沉淀分析表明RUNX1/CBFbeta与GATA有物理联系。这种新的功能和物理关联与最近GATA-1和RUNX1基因在遗传性综合征合并血小板减少症中的临床意义相关。RUNX1的显性负变异体包括与ETO转录抑制因子的融合，这种融合是急性髓系白血病中常见的t(8；21)染色体异常的结果。我们发现，与野生型RUNX1相比，RUNX1-ETO癌蛋白有效地抑制了GATA-1的巨核细胞启动子的激活。此外，RUNX1-ETO展示了与GATA-1的物理相互作用。因此，RUNX1-ETO的致癌作用之一可能是阻断GATA诱导的造血分化。本项目的主要目的是：1)阐明RUNX1与GATA-1在巨核细胞生成中的协同作用的发育后果和分子机制；2)确定RUNX1-ETO抑制GATA因子的发育后果和分子机制。