GABP Transcription Factor in Myeloid Differentiation

骨髓分化中的 GABP 转录因子

基本信息

批准号：
6920084
负责人：
ALAN G ROSMARIN
金额：
$ 37.41万
依托单位：
RHODE ISLAND HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-08-01 至 2009-07-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The goal of this proposal is to comprehensively characterize the role of the transcription factor, GA-Binding Protein (GABP). in myeloid differentiation and gene expression. Transcription factors regulate development of myeloid cells (granulocytes and monocytes) from hematopoietic progenitor cells, and defects in transcription factors are associated with acute myelogenous leukemia. GABP is 1 of a limited number of transcription factors that regulate myeloid genes. It is a tetrameric complex that consists of 2 distinct proteins: 1) GABPalpha, an ets factor which binds to DNA, and 2) GABPbeta, a Notch-related protein which contains transcription activation and multimerization domains. GABP transcriptionally activates CD 18 (beta2 leukocyte integrin) and other myeloid genes; it is required for transcriptional activation of CD18 in response to retinoic acid. As granulocytes and monocytes differentiate, distinct isoforms of GABPbeta with specific transcriptional activation properties are expressed; conditional expression some GABP beta isoforms induces granulocytic differentiation and characteristic gene expression. The proposal will test the hypothesis that GABP mediates an alternative pathway to granulocytic differentiation and that specific GABPbeta isoforms are required during myeloid differentiation. GABP cooperates with PU.1, Sp1, RARalpha, and p300 to activate CD18. This proposal will use pull-down assays, co-immunoprecipitation, and chromatin immunoprecipitation to define the physical and functional interactions of GABP with other key myeloid transcription factors and co-activators. It will test the hypothesis that GABP participates in an enhanceosome - a multiprotein complex that regulates myeloid gene expression. Mice were generated with loxP recombination sites that flank the GABPalpha ets domain. GABPalpha is efficiently deleted in vivo and in vitro; homozygous deletion of GABPalpha in mice causes an early embryonic lethal defect. Selective disruption of GABPalpha in myeloid cells indicates that they require GABP for survival and/or differentiation. Downstream targets of GABP that may account for cellular defects of GABPalpha null cells have been identified. The proposal will test the hypothesis that GABP is required for granulocytic survival and/or differentiation and it will define mechanisms by which GABP drives myeloid cell development. These studies will provide a comprehensive demonstration of the role of GABP in myeloid gene expression and provide important new information regarding transcription factor and co-activator interactions that regulate myeloid differentiation.

描述（由申请人提供）：该提案的目的是全面表征转录因子GA结合蛋白（GABP）的作用。在髓样分化和基因表达中。转录因子调节造血祖细胞的髓样细胞（粒细胞和单核细胞）的发育，转录因子的缺陷与急性骨髓性白血病有关。 GABP是调节髓样基因的有限数量的转录因子的1。这是一种四聚体复合物，由2种不同的蛋白质组成：1）Gabpalpha，一种与DNA结合的ETS因子，以及2）Gabpbeta，gabpbeta是一种与凹槽相关的蛋白质，其中包含转录激活和多聚体域。 GABP转录激活CD 18（β2白细胞整合素）和其他髓样基因；响应视黄酸的转录激活是必需的。随着粒细胞和单核细胞的区分，具有特定转录激活特性的GABPBETA的不同同工型。条件表达一些GABPβ同工型诱导粒细胞分化和特征基因表达。该提案将检验以下假设：GABP介导粒细胞分化的替代途径，并且在髓样分化过程中需要特定的GABPBETA同工型。 GABP与PU.1，SP1，Raralpha和P300合作以激活CD18。该建议将使用下拉测定，共免疫沉淀和染色质免疫沉淀来定义GABP与其他关键的髓样转录因子和共激活剂的物理和功能相互作用。它将测试GABP参与增强酶体的假设 - 一种调节髓样基因表达的多蛋白络合物。小鼠是用侧面Gabpalpha ETS结构域的LOXP重组位点产生的。 gabpalpha在体内和体外有效删除；小鼠Gabpalpha的纯合缺失会导致早期的胚胎致命缺陷。髓样细胞中GABPALPHA的选择性破坏表明它们需要GABP才能生存和/或分化。已经确定了可能解释GABPALPHA无效细胞细胞缺陷的GABP的下游靶标。该提案将检验以下假设：GABP是粒细胞存活和/或分化所必需的，它将定义GABP驱动髓样细胞发育的机制。这些研究将为GABP在髓样基因表达中的作用提供全面的证明，并提供有关调节髓样分化的转录因子和共激活因子相互作用的重要新信息。