Ubiquitin-Proteolytic Control of HOXA9 in Leukemogenesis

HOXA9 在白血病发生中的泛素蛋白水解控制

• 批准号: 7547053
• 负责人: Pengbo Zhou
• 金额: $ 29.06万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-27 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7547053
• 关键词: Ablation; Acute Myelocytic Leukemia; Address; Affect; Binding; Biochemical; Bone Marrow; Bone Marrow Cells; Chromosomal translocation; Complex; DNA; Data; Development; Future; Gene Delivery; Genes; Goals; HOX protein; HOXA9 gene; HOXA9 protein; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Homeodomain Proteins; In Vitro; Incidence; Investigation; Knock-out; Knockout Mice; Leukocytes; Malignant - descriptor; Maps; Mediating; Molecular; Molecular Genetics; Mus; Myelogenous; NUP98 gene; Oncogenic; Pathogenesis; Patients; Play; Proteins; Proteolysis; Regulation; Research; Research Personnel; Resistance; Role; Signal Transduction; Site-Directed Mutagenesis; Small Interfering RNA; Stem cells; Structure; System; Testing; Transcriptional Regulation; Transplantation; Ubiquitin; Ubiquitination; Yeasts; base; cullin 4A; gene delivery system; homeodomain; in vivo; leukemia; leukemogenesis; mouse model; mutant; novel; peripheral blood; positional cloning; programs; protein degradation; receptor; stem; tool; ubiquitin ligase; yeast two hybrid system

The HOX homeodomain (HD) proteins are key regulators of hematopoiesis. Aberrant expression or chromosomal translocations involving certain HOX proteins, such as HOXA9, have been implicated in the pathogenesis of acute myeloid leukemia (AML). Our understanding of how the intracellular levels and activities of the HOX proteins are controlled during hematopoiesis is current limited to transcriptional regulation and signal transduction. Little isknown about the posttranslational control mechanisms that govern the abundance of the HOX hematopoietic regulators and the functional significance for such regulations. The long-term goal of this study is to understand how ubiquitin- dependent protein degradationregulates normal and malignant hematopoiesis. The central hypothesis of the application is that the cullin 4A (CUL-4A) ubiquitin-ligase controls hematopoietic development throughtargeted degradation of key hematopoietic regulators. The hypothesis has been formulated on the basis of strong preliminary data, which demonstratedthat CUL-4A targets HOXA9 for degradation, and regulates myeloid differentiationand maturation. Hematopoietic-specific knockout of the CUL-4A gene in mice led to an increased expansion of bone marrow progenitor cells and peripheral blood leukocytes. This proposal seeks to determine the biochemical mechanisms underlying the CUL-4A-dependent proteolytic control of HOXA9 and the chromosomal translocation- derived NUP98-HOXA9 fusion, and to elucidate the functional significance of CUL-4A in suppressing leukemic transformation. We are uniquely prepared to undertake the proposed research, since we have recently generateda CUL-4A-resistant HOXA9 mutant, and developed conditional CUL-4A knockout mice and CUL-4A siRNA to eliminate or modulate CUL-4A activity. We have also optimized lentiviral- and retroviral-based gene delivery systemsfor efficient transduction in primary hematopoietic stem and progenitor cells. We propose to combine the biochemical and molecular genetic approachesin Dr. Pengbo Zhou's lab and the expertise in ex vivo and in vivo hematopoieticanalysis in Dr. Malcolm Moore's lab to address the following specific aims: (1) to define the biochemical mechanisms underlying CUL~4A-dependent ubiquitination and degradation of HOXA9. (2) to elucidate the functional significance of HOXA9 degradation by CUL-4A in the pathogenesis of AML. (3) to determine the molecular basis for CUL-4A resistanceby the leukemogenic NUP98-HOXA9fusion and to assess the impact of CUL-4A ablation in the mouse model of NUP98- HOXA9-induced leukemia. Since little information is available regarding the roles of protein degradation during leukemogenesis, successful completion of this proposal will represent a significant advance in understanding a novel posttranslational mechanism that governs the functions of key hematopoietic regulators, and provide a frameworkfor future investigations of targeted protein degradation in normal and malignant hematopoiesis.

HOX同源域（HD）蛋白是造血的关键调节剂。异常表达或染色体 涉及某些HOX蛋白（例如Hoxa9）的易位已与急性发病机理有关 髓样白血病（AML）。我们对HOX蛋白的细胞内水平和活动的理解 造血期间控制的当前仅限于转录调控和信号转导。鲜为人知 关于控制霍克斯造血调节剂和的翻译后控制机制 此类法规的功能意义。这项研究的长期目标是了解泛素如何 依赖性蛋白质降解对正常和恶性造血作用。中心假设 应用是Cullin 4A（CUL-4A）泛素 - 牵引酶控制造血发育。 关键造血调节剂的降解。该假设是根据强有力的初步提出的 数据证明了CUL-4A的靶向HOXA9进行降解，并调节骨髓分化和 成熟。小鼠CUL-4A基因的造血特异性敲除导致骨骼的扩张增加 骨髓祖细胞和外周血白细胞。该建议旨在确定生化 CUL-4A依赖性蛋白水解控制HOXA9和染色体易位 - 派生的NUP98-HOXA9融合，并阐明CUL-4A在抑制白血病中的功能意义 转型。我们已经准备好进行拟议的研究，因为我们最近产生了 CUL-4A耐药HOXA9突变体，并开发了有条件的CUL-4A敲除小鼠和CUL-4A siRNA消除或 调节CUL-4A活性。我们还优化了基于慢病毒和逆转录病毒的基因递送系统，以提高效率 原发性造血干和祖细胞的转导。我们建议将生化和 分子遗传方法在Pengbo Zhou博士的实验室以及体内和体内造血分析方面的专业知识 在Malcolm Moore博士的实验室中，以解决以下特定目的：（1）定义生化机制 HOXA9的依赖性泛素化和降解。 （2）阐明Hoxa9的功能意义 CUL-4A降解在AML的发病机理中。 （3）确定CUL-4A抗性的分子基础 白血病NUP98-HOXA9FUSION并评估CUL-4A消融在NUP98-小鼠模型中的影响 HOXA9引起的白血病。由于很少有有关蛋白质降解作用的信息 白血病生成，该提案的成功完成将代表理解新颖的重大进步 控制关键造血调节剂功能的翻译后机制，并提供一个框架 对正常和恶性造血的靶向蛋白质降解的未来研究。