A protein-directed RNA switch that regulates translation

调节翻译的蛋白质导向的 RNA 开关

• 批准号: 9026295
• 负责人: PAUL L FOX
• 金额: $ 4.54万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9026295
• 关键词: 3' Untranslated Regions; 5' Untranslated Regions; Amino Acyl-tRNA Synthetases; Bacteria; Beryllium; Binding; Binding Proteins; Binding Sites; Bioinformatics; Blood Vessels; Cells; Complex; Elements; Environment; Funding; Gene Expression; Goals; Growth; Half-Life; Heterogeneous-Nuclear Ribonucleoprotein L; Heterogeneous-Nuclear Ribonucleoproteins; Hydroxylation; Hypoxia; Indium; Inflammation; Inflammatory; Interferon Type II; Interferons; Mammalian Cell; Maps; Masks; Mediating; Messenger RNA; Molecular; Molecular Conformation; Myeloid Cells; Pathway interactions; Pattern; Phosphorylation; Phosphotransferases; Physiological; Process; Procollagen-Proline Dioxygenase; Protein Family; Proteins; RNA; RNA Conformation; RNA Splicing; RNA Stability; RNA-Binding Proteins; RNA-Protein Interaction; Regulation; Regulon; Reporting; Research; Ribonucleoproteins; Role; Signal Transduction; Site; Specificity; Stimulus; Structure; Testing; Tissues; Transcript; Translational Repression; Translations; Ubiquitin; Untranslated Regions; Validation; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; Vertebrates; abstracting; angiogenesis; base; blood vessel development; conformer; ds RNA-Binding Proteins; genome-wide; human VEGF protein; inhibitor/antagonist; insight; mRNA Precursor; macrophage; member; messenger ribonucleoprotein; multicatalytic endopeptidase complex; new therapeutic target; novel; nuclease; prevent; programs; proline-tRNA; protein expression; public health relevance; response; sensor; tumor; tumor growth

DESCRIPTION (provided by applicant): Project Summary/Abstract Our long-term goal is to understand how interactions between elements in noncoding regions of vertebrate mRNAs and their cognate binding proteins integrate signals from disparate stimuli to control translation. Tran- script-selective translationl control is mediated by interactions of RNA-binding proteins to sequence/structural elements in the 5'- or 3'-untranslated region (UTR) of target transcripts. Recently, an additional layer of com plexity has been recognized in which element pairs act as condition-dependent RNA switches. For example, riboswitches are proximate structural elements in the UTR of multiple bacterial mRNAs that undergo conforma- tional changes in response to specific metabolites. We have reported an analogous, stimulus-dependent switch in the 3'UTR of human vascular endothelial growth factor (VEGF)-A mRNA. VEGF-A mRNA contains adjoining elements that function as a novel stimulus-dependent, protein-directed RNA switch that exists in two metastable conformations: a translation-silencing and a translation-permissive conformer. The binary switch is controlled by integration of two signals, interferon (IFN)-γ and hypoxia, that regulate the amount or activity of the binding factors. Upon cell stimulation by IFN-γ, phosphorylation of Glu-Pro tRNA synthetase (EPRS) initiates formation of the GAIT (IFN-Gamma-Activated Inhibitor of Translation) complex. EPRS binds a defined, GAIT element in the VEGF-A mRNA 3'UTR, stabilizing the translation-silencing conformer and inhibiting translation. However, superimposition of hypoxia on IFN-γ stimulation induces phosphorylation of hnRNP L at Tyr359 that initiates assembly of a newly discovered 3-component HILDA complex that binds a CA-rich element directly upstream of the GAIT element, stabilizing the translation-permissive conformer and allowing VEGF-A expression. We propose the following specific hypothesis: Myeloid cells integrate signals from IFN-γ and hypoxia by inducing Tyr359 phosphorylation of hnRNP L and assembly of the HILDA complex, which in turn directs an RNA switch in the 3'-UTR of VEGF-A and other inflammation-related mRNAs to regulate translation. We will test this hypothesis by pursuing the following Specific Aims: Aim 1: Investigate molecular mechanisms regulating hnRNP L expression and localization; Aim 2: Determine the functions of HILDA components in regulating the RNA switch; Aim 3: Identify novel transcripts controlled by protein-directed RNA switches. We suggest that the switch evolved to maintain VEGF-A expression and angiogenesis in hypoxic, inflammatory tissues. Tumors, also residing in hypoxic, inflammatory sites, may take advantage of the VEGF-A switch to stimulate inward blood vessel growth to provide nourishment and permit tumor growth. Thus, the VEGF-A switch represents a novel therapeutic target to specifically inhibit tumor macrophage expression of VEGF-A. We also speculate that the VEGF-A switch may represent the founding member of a family of protein-directed RNA switches in vertebrates that integrate physiological or pathological stimuli to control gene expression.

描述（由申请人提供）： 项目摘要/摘要我们的长期目标是了解脊椎动物mRNA的非编码区域中元素之间的相互作用如何与它们的同源结合蛋白整合了不同刺激的信号以控制翻译。跨文字选择性翻译控制L是由RNA结合蛋白与目标转录本5'-或3'-非翻译区（UTR）中的序列/结构元素的相互作用介导的。最近，已经识别出一个额外的复杂性层，其中元素对充当条件依赖性的RNA开关。例如，核糖开关是多种细菌mRNA的UTR中的近端结构元素，其响应于特定的代谢产物而发生符合性变化。我们报道了人血管内皮生长因子（VEGF）-A mRNA的3'UTR中的类似刺激依赖性转换。 VEGF-A mRNA包含相邻的元素，它们是一种新型刺激依赖性的，蛋白质指导的RNA开关，存在于两个亚稳态构象中：一种翻译成分和一种翻译 - 允许的构象。二进制开关通过两个信号（IFN）-γ和缺氧的两个信号的整合来控制，这些信号调节结合因子的数量或活性。在通过IFN-γ刺激细胞时，GLU-PRO TRNA合成酶（EPRS）的磷酸化启动了步态（IFN-GAMMA激活的翻译抑制剂）复合物的形成。 EPRS在VEGF-A mRNA 3'UTR中结合了一个定义的步态元件，稳定了翻译 - 沉默的构象异构体和抑制翻译。然而，在IFN-γ模拟上的缺氧叠加会在Tyr359诱导HNRNP L的磷酸化，从而启动了新发现的新发现的3组分Hilda复合物的组装，该组件将步态元件的富含CA的元素直接粘合，从而稳定了翻译 - 经验性的构象和允许vegf-a表达。我们提出以下特定假设：通过诱导的HNRNP L的Tyr359磷酸化和HILDA复合物的组装诱导的Tyr359磷酸化和HILDA复合物的组装，从IFN-γ和缺氧整合了信号，这反过来又指导了VEGF-A的3'-UTR中的RNA开关，并引发了其他炎症与其他相关的MRNA相关的MRNA进行调节翻译。我们将通过追求以下特定目的来检验这一假设：目标1：研究分子机制调节HNRNP L表达和定位； AIM 2：确定Hilda组件在调节RNA开关中的功能； AIM 3：确定由蛋白质指导的RNA开关控制的新成绩单。我们建议该开关在低氧，炎症组织中维持VEGF-A表达和血管生成。肿瘤也居住在低氧，炎症部位，可能会利用VEGF-A转换来刺激内部血管生长，以提供营养并允许肿瘤生长。这是VEGF-A开关代表一个新型的热靶标，用于特异性抑制VEGF-A的肿瘤巨噬细胞表达。我们还推测，VEGF-A开关可能代表脊椎动物中蛋白质指导的RNA开关的创始成员，这些脊椎动物将物理或病理刺激整合以控制基因表达。