Fragile X Mental Retardation Protein translation regulator function: interactions

脆性 X 精神发育迟滞 蛋白质翻译调节功能：相互作用

• 批准号: 8494883
• 负责人: MIHAELA R MIHAILESCU
• 金额: $ 39.42万
• 依托单位: DUQUESNE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8494883
• 关键词: 3' Untranslated Regions; Address; Adopted; Affect; Affinity; Alternative Splicing; Arginine; Belgium; Binding; Binding Sites; Biochemical; Biogenesis; Biological Process; Boxing; Code; Complex; Enhancers; Exons; FMR1; FMR1 Gene; Feedback; Female; Fragile X Mental Retardation Protein; Fragile X Syndrome; Functional RNA; G-Quartets; Glycine; Goals; Guide RNA; Inherited; KH Domain; Laboratories; Length; Mediating; Mental Retardation; Messenger RNA; Methylation; MicroRNAs; Molecular; Mutate; Names; Nucleotides; Pathway interactions; Patients; Phenotype; Phosphorylation; Phosphorylation Site; Post-Translational Protein Processing; Production; Property; Protein Biosynthesis; Protein Isoforms; Proteins; RNA; RNA Binding; RNA Interference; RNA Recognition Motif; RNA Sequences; RNA Splicing; RNA-Binding Proteins; Regulation; Research; SUI1 gene; Site; Specificity; Structure; Synapses; Syndrome; Testing; Translations; Work; in vivo; male; novel; postsynaptic density protein; prevent; public health relevance; research study; response

DESCRIPTION (provided by applicant): Fragile X mental retardation syndrome is the most common form of inherited mental retardation, affecting ~ 1 in 3600 males and ~ 1 in 6000 females. The syndrome is caused by the loss of a normal cellular protein, named the fragile X mental retardation protein (FMRP). Despite extensive research in the past two decades, the relationship between the absence of FMRP and the phenotype of the fragile X syndrome is still not fully understood. FMRP is an RNA binding protein involved in the transport and translation regulation of specific messenger RNA (mRNA) targets. Biochemical studies have determined that FMRP uses its arginine-glycine- glycine (RGG) box to bind with high affinity to RNA sequences that form G quadruplex structures. The mechanisms by which FMRP exerts its translation regulator function are not known, however it has recently been proposed that the protein works in conjunction with the microRNA pathway to regulate local protein synthesis in response to synaptic input. This proposal has the following specific aims: 1. Biochemical analysis of the miRNA-mediated translational regulator function of FMRP. We hypothesize that FMRP exerts its translation regulator function on a sub-class of its mRNA targets containing miRNA- binding sites, by altering their structures to facilitate/prevent their interactions with th miRNA-guided RISC, which will suppress/allow their translation in response to synaptic input. 2. Biochemical characterization of FMRP isoforms 2 and 3: interactions with FMR1 mRNA and translational regulator function in the context of the miRNA pathway. It has been shown that phosphorylation is essential in modulating the miRNA-mediated translation regulator function of FMRP. We will determine how the FMRP isoforms 2 and 3 interactions with the miRNA pathway are affected by their inability to be regulated through phosphorylation, due to the loss of the sites of phosphorylation from their sequence through alternative splicing. We will also determine if the production of the FMRP isoforms 2 and 3 is regulated through feedback inhibition due to their high binding affinity for the G quadruplex exonic splicing enhancer site within FMR1 mRNA. 3. Functional characterization of a C-terminus frame-shifted FMRP, which causes fragile X syndrome. There is recent evidence that the fragile X syndrome is caused in a patient in Belgium by a G insertion in the RGG box coding region of the FMR1 gene, which leads to a C-terminus frame shifted FMRP. We will determine if this C-terminus frame-shifted FMRP leads to fragile X syndrome due to the altered sequence of its RGG box, which will impair its ability to bind to G quadruplex RNA and exert its translation regulator function within or outside of the miRNA pathway context.

描述（由申请人提供）：脆性X染色体智力低下综合征是遗传性智力低下的最常见形式，影响约1/3600男性和约1/6000女性。这种综合征是由一种正常细胞蛋白质的丢失引起的，这种蛋白质被称为脆性X智力低下蛋白（FMRP）。尽管在过去的二十年中进行了广泛的研究，但FMRP缺失与脆性X综合征表型之间的关系仍未完全了解。FMRP是一种RNA结合蛋白，参与特异性信使RNA（mRNA）靶点的转运和翻译调节。生物化学研究已经确定FMRP使用其甘氨酸-甘氨酸-甘氨酸（RGG）盒以高亲和力结合形成G四链体结构的RNA序列。FMRP发挥其翻译调节功能的机制尚不清楚，但最近有人提出，该蛋白与microRNA通路结合，以调节局部蛋白质合成，以响应突触输入。这项建议的具体目标如下：1. FMRP的miRNA介导的翻译调节功能的生化分析。我们假设FMRP通过改变其结构以促进/阻止其与miRNA引导的RISC的相互作用，从而在其含有miRNA结合位点的mRNA靶点的亚类上发挥其翻译调节剂功能，这将抑制/允许其响应于突触输入的翻译。 2. FMRP亚型2和3的生物化学表征：在miRNA途径中与FMR 1 mRNA和翻译调节因子功能的相互作用。已经显示磷酸化在调节FMRP的miRNA介导的翻译调节剂功能中是必需的。我们将确定FMRP亚型2和3与miRNA通路的相互作用如何受到它们无法通过磷酸化调节的影响，这是由于通过选择性剪接从它们的序列中丢失了磷酸化位点。我们还将确定FMRP亚型2和3的产生是否通过反馈抑制来调节，因为它们对FMR 1 mRNA内的G四链体外显子剪接增强子位点具有高结合亲和力。 3.导致脆性X综合征的C-末端移码FMRP的功能表征最近有证据表明，脆性X综合征是由比利时的一名患者在FMR 1基因的RGG盒编码区插入G引起的，这导致了C端移码FMRP。我们将确定这种C-末端移码FMRP是否会由于其RGG盒序列的改变而导致脆性X综合征，这将损害其与G四链体RNA结合的能力，并在miRNA通路内或外发挥其翻译调节功能。