Role of C-myb in Hematopoiesis and Cancer

C-myb 在造血和癌症中的作用

• 批准号: 7629613
• 负责人: E Premkumar Reddy
• 金额: $ 37.5万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7629613
• 关键词: Address; Adult; Alternative Splicing; Anemia; Biological; Biological Models; Bone Marrow; Bone Marrow Cells; C-terminal; Cell Proliferation; Cell Survival; Cell physiology; Cells; Competence; Development; Embryo; Erythropoiesis; Exhibits; Exons; Gene Family; Gene Proteins; Genes; Genetic Models; Genetic Recombination; Genetic Transcription; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Hepatic; IL2RA gene; Impairment; In Vitro; Interferon Type I; Knockout Mice; Lead; Lymphoid; MYB gene; Maintenance; Malignant Neoplasms; Mediating; Molecular; Molecular Analysis; Mouse Strains; Mus; Mutant Strains Mice; Myelogenous; Myeloid Cells; Myeloid Leukemia; Myelopoiesis; Names; Nuclear Protein; Nuclear Proteins; Play; Population; Protein Binding; Protein Isoforms; Proteins; Proteomics; Proto-Oncogene Proteins c-myb; Publishing; RNA Splicing; Retroviridae; Role; Staging; Stem Cell Development; System; T-Cell Development; T-Lymphocyte; Tissues; Transactivation; Transgenic Organisms; base; embryonic stem cell; fetal; gene function; hematopoietic tissue; in utero; in vivo; leukemia; leukemogenesis; member; mouse development; mouse model; mutant; myb Genes; progenitor; research study; self-renewal; transcriptional coactivator p75; tumorigenesis

DESCRIPTION (provided by applicant): It is now well established that the c-myb gene encodes for two proteins, p75-Myb and p89-Myb, and plays a critical role in the development, proliferation and oncogenesis of hematopoietic cells. Because constitutive loss of the c-myb gene leads to embryonic lethality, it has not been possible to accurately assess the role of this gene in the maintenance of adult hematopoiesis. To overcome this problem and to investigate the function of this gene in adult hematopoiesis, we used the Cre-LoxP recombination system to achieve tissue-specific deletion of c-myb. In a recently published study, we have generated two T cell-specific c-myb knockout mouse models mybF/F/LckCre and mybF/F/CD4Cre, which delete c-myb at two specific stages of T cell development. Studies with these mice have allowed us to define the role of c-myb in T cell development and function. In contrast to the function of p75-c-Myb, the role of p89c-Myb in hematopoiesis is not known. To examine the function of the p89c- myb isoform, we have generated a mouse model where exon 9A is deleted, and as a consequence, this mutant mouse is incapable of producing the p89-c-Myb. A role for c-myb in leukemogenesis was established when It was shown that retrovirus-induced mouse myeloid leukemias express a C- terminal truncated form of c-myb (termed t-myb), which exhibits enhanced transactivating and transformation activities. To determine the biological effects of myb gene truncation during mouse development and hematopoiesis, we have generated a strain of mice which express a C-terminal deletional mutant of c-Myb conditionally. In this application, we propose to use these powerful mouse genetic models to determine the roles played by p75 and p89 isoforms of c-Myb in hematopoiesis and the consequence of C-terminal truncation of c-Myb in hematopoiesis and leukemogenesis. The aims are: 1. To ascertain the molecular mechanisms by which c-Myb regulates T-cell development at the DP stage, gene array and proteomics analysis will be performed, and the functions of those altered genes and proteins will be assessed using both in vivo and in vitro conditions. 2. To determine the role of c-myb in adult hematopoiesis and myeloid development. 3. To define the role of c-myb in Hematopoietic Stem Cell (HSC) development and function. 4. To determine the roles of an alternatively spliced form of c-myb, the p89c-myb, and a genetically truncated version of c-myb, t- myb, in lineage commitment, proliferation and survival of myeloid progenitors and HSCs; and 5. To examine the role of c-myb in BCRABL-mediated transformation of myeloid cells.

描述（由申请人提供）：现在已经很好地确定，C-MYB基因编码两种蛋白质P75-MYB和P89-MYB，并且在造血细胞的发育，增殖和发作中起着至关重要的作用。由于c-MYB基因的构型丧失会导致胚胎致死性，因此无法准确评估该基因在维持成年造血的作用。为了克服这个问题并研究该基因在成年造血中的功能，我们使用CRE-LoxP重组系统实现了C-MYB的组织特异性缺失。在最近发表的一项研究中，我们已经生成了两个T细胞特异性的C-MYB敲除小鼠模型MYBF/F/LCKCRE和MYBF/F/CD4CRE，它们在T细胞开发的两个特定阶段删除C-MYB。对这些小鼠的研究使我们能够定义C-MYB在T细胞发育和功能中的作用。与p75-c-myb的功能相反，尚不清楚p89c-myb在造血中的作用。为了检查p89c- myb同工型的功能，我们生成了一个小鼠模型，其中删除了外显子9a，因此，该突变小鼠无法产生p89-c-myb。当表明逆转录病毒诱导的小鼠髓样白血病表达c-Myb（称为T-MYB）的C-末端截断形式（称为T-MYB）时，C-MYB在白血病发生中的作用，该作用表现出增强的反式激活和转化活性。为了确定小鼠发育和造血过程中Myb基因截断的生物学作用，我们产生了一小鼠，该菌株有条件地表达了C-MYB的C末端缺失突变体。在此应用中，我们建议使用这些强大的小鼠遗传模型来确定C-MYB在造血中的P75和P89同工型的作用，以及C-MYB在造血和白血病发生中C末端截断的结果。目的是：1。要确定C-MYB在DP阶段调节T细胞发育的分子机制，将进行基因阵列和蛋白质组学分析，并且将使用体内和体外条件来评估这些改变的基因和蛋白质的功能。 2。确定C-MYB在成年造血和髓样发育中的作用。 3。定义C-MYB在造血干细胞（HSC）发育和功能中的作用。 4。确定C-MYB的剪接形式的作用，P89C-MYB以及C-Myb，T-MYB的遗传截断版本在谱系承诺，髓样祖细胞和HSC的谱系承诺，增殖和存活中； 5。检查c-Myb在BCRABL介导的髓样细胞转化中的作用。