Regulation of Mammalian mRNA decapping

哺乳动物 mRNA 脱帽的调控

• 批准号: 7729816
• 负责人: MEGERDITCH KILEDJIAN
• 金额: $ 32.83万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7729816
• 关键词: Affect; Biochemical; Cells; Development; Disease; Erythrocytes; Funding; Gene Expression; Genes; Genetic Translation; Globin; Human; Hydrolysis; Life; Link; Malignant Neoplasms; Mammalian Cell; Mammals; Mediating; Mental Retardation; Messenger RNA; Modeling; Molecular; Motor Neurons; Nature; Neurons; Nuclear; Pathway interactions; Perception; Post-Transcriptional Regulation; Process; Proteins; Proto-Oncogenes; RNA Cap-Binding Proteins; Regulation; Role; Spinal Muscular Atrophy; Structure; Testing; Thalassemia; Therapeutic; Therapeutic Intervention; Tissues; Transcript; Translations; Work; X-Linked Mental Retardation; base; cell type; clinical phenotype; cytokine; decapping enzyme; drug candidate; genetic manipulation; insight; interest; mRNA Decay; mRNA Stability; mRNA capping; mRNA decapping; novel; novel strategies; novel therapeutics; nuclease; programs; protein function; public health relevance; therapeutic gene

DESCRIPTION (provided by applicant): The control of mRNA stability is a critical determinant in the post-transcriptional regulation of eukaryotic gene expression. Changes in mRNA stability can have profound consequences and may manifest as clinical phenotypes. This is perhaps best illustrated by the ability of aberrantly expressed proto-oncogenes that can give rise to malignancies and by the imbalanced 1 and 2 globin gene expression resulting in thalassemias. Despite the importance of mRNA stability in the control of gene expression, progress has only recently been made in the identification and characterization of the components that control mRNA turnover. We have focused our efforts on the study of nucleases and the pathways involved in mRNA decay in mammals, in particular, the two decapping enzymes, Dcp2 and DcpS. Dcp2 is the mRNA decapping enzyme that functions on capped mRNA while DcpS functions as the clearinghouse to hydrolyze the resulting cap structure following 34 to 54 decay of an mRNA. The long-term objective of this proposal is to understand the mechanisms that regulate mRNA decapping and mRNA decay in mammals and to utilize this information to control gene expression under normal and disease states. We have shown that Dcp2 is a transcript-specific decapping protein that is not uniformly expressed and is even undetectable in certain tissues indicating that there are as yet unknown decapping enzymes in mammals. We have also identified a protein implicated in X-linked mental retardation as a regulator of decapping. Furthermore, we have shown that DcpS is a modulator of the nuclear cap binding protein-mediated functions in addition to its role in mRNA turnover as well as the target substrate of a drug candidate for the treatment of spinal muscular atrophy. In this proposal, i) we will test the impact of Dcp2 and its absence on mRNA decay and identify the non-Dcp2 mRNA decapping enzyme in mammalian cells in Aim I; ii) characterize the mechanism by which the decapping regulator influences mRNA stability in Aim 2; and iii) assess the modulatory role of DcpS on cytoplasmic functions including mRNA stability and translation in Aim 3. This work will provide insights into a fundamental mechanism involved in the post-transcriptional control of gene expression and will provide a framework for novel approaches for therapeutic intervention in human disorders. PUBLIC HEALTH RELEVANCE: Our overall objective is to understand the precise controls involved in mRNA turnover and to utilize this information to regulate gene expression under normal and disease states. Decapping is a key step in the stability and ultimate demise of an mRNA. We will build on our ongoing functional studies of the Dcp2 and DcpS decapping enzymes in mammalian gene expression and their correlation to both mental retardation and spinal muscular atrophy. We will determine the impact of the presence, and surprising natural absence, of Dcp2 in mRNA decay, its regulation and the modulatory function of DcpS on cytoplasmic cap-binding protein processes. This work will provide insight into a fundamental mechanism involved in the post-transcriptional control of gene expression and could provide a framework in novel approaches for therapeutic intervention.

描述（由申请人提供）：mRNA稳定性的控制是真核基因表达转录后调控的关键决定因素。 mRNA 稳定性的变化可能会产生深远的后果，并可能表现为临床表型。异常表达的原癌基因可能导致恶性肿瘤，以及导致地中海贫血的 1 和 2 珠蛋白基因表达失衡，这也许是最好的说明。尽管 mRNA 稳定性在基因表达控制中很重要，但控制 mRNA 周转成分的鉴定和表征直到最近才取得进展。我们主要致力于研究核酸酶和哺乳动物 mRNA 衰变所涉及的途径，特别是两种脱帽酶 Dcp2 和 DcpS。 Dcp2 是 mRNA 脱帽酶，作用于加帽的 mRNA，而 DcpS 则充当交换中心，在 mRNA 34 至 54 次衰变后水解所得帽结构。该提案的长期目标是了解哺乳动物中调节 mRNA 脱帽和 mRNA 衰变的机制，并利用这些信息来控制正常和疾病状态下的基因表达。我们已经证明Dcp2是一种​​转录特异性脱帽蛋白，其表达不均匀，甚至在某些组织中无法检测到，这表明哺乳动物中尚存在未知的脱帽酶。我们还发现了一种与 X 连锁智力低下有关的蛋白质，作为脱帽的调节剂。此外，我们还表明，DcpS 除了在 mRNA 周转中发挥作用外，还是核帽结合蛋白介导功能的调节剂，也是治疗脊髓性肌萎缩症候选药物的靶底物。在此提案中，i) 我们将测试 Dcp2 及其缺失对 mRNA 衰减的影响，并在 Aim I 中鉴定哺乳动物细胞中的非 Dcp2 mRNA 脱帽酶； ii) 描述目标 2 中脱帽调节剂影响 mRNA 稳定性的机制； iii) 评估目标 3 中 DcpS 对细胞质功能（包括 mRNA 稳定性和翻译）的调节作用。这项工作将深入了解涉及基因表达转录后控制的基本机制，并将为人类疾病治疗干预的新方法提供框架。公共健康相关性：我们的总体目标是了解 mRNA 更新所涉及的精确控制，并利用这些信息来调节正常和疾病状态下的基因表达。脱帽是 mRNA 稳定性和最终消亡的关键步骤。我们将继续对哺乳动物基因表达中的 Dcp2 和 DcpS 脱帽酶及其与智力低下和脊髓性肌萎缩症的相关性进行功能研究。我们将确定 Dcp2 的存在和令人惊讶的自然缺失对 mRNA 衰减的影响、其调节以及 DcpS 对细胞质帽结合蛋白过程的调节功能。这项工作将深入了解基因表达转录后控制所涉及的基本机制，并为治疗干预的新方法提供框架。