REPEAT-ASSOCIATED NON-ATG TRANSLATION IN DM1 AND DM2

DM1 和 DM2 中重复相关的非 ATG 翻译

• 批准号: 8739677
• 负责人: Laura P.W Ranum
• 金额: $ 40.34万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8739677
• 关键词: Animals; Antithymoglobulin; Astrocytes; Autopsy; Biochemical; Blood; Brain; CAG repeat; Categories; Cell Culture Techniques; Cells; Cerebrospinal Fluid; Code; Codon Nucleotides; DNA; Data; Disease; Dominant-Negative Mutation; Functional RNA; Functional disorder; Gene Expression; Genome; Goals; In Vitro; Individual; Infiltration; Inflammatory; Initiator Codon; Knock-out; Length; Link; Location; Microsatellite Repeats; Modeling; Molecular; Molecular Biology; Mus; Mutation; Myotonic Dystrophy; Neuroglia; Neurons; Nuclear; Pathogenesis; Pathologic; Pathology; Patients; Play; Process; Proteins; RNA; RNA Editing; Relative (related person); Research; Role; Signal Transduction; Site; Testing; Therapeutic; Tissues; Toxic effect; Transcript; Translating; Translations; disease-causing mutation; gain of function; in vivo; insight; loss of function; macrophage; monocyte; mouse model; mutant; nervous system disorder; novel; overexpression; protein expression; research study

Repeat-Associated Non-ATG Translation in DM1 and DM2 (Project 1)- Ranum Well-established rules of translational initiation have been used as a cornerstone in molecular biology to understand gene expression and to predict the consequences of disease causing mutations. For myotonic dystrophy (DM) and other microsatellite expansion disorders, repeat expansions (e.g., CAG or CTGs) located in predicted coding- and non-coding regions are thought to cause disease by protein gain-, or loss-of- function or RNA gain-of-function mechanisms. In 2001, we showed that myotonic dystrophy type 2 (DM2) is caused by an intronic CCTG*CAGG expansion in CNBP. The apparent non-coding locations of the DM1 and DM2 expansion mutations and the accumulation of RNA foci in both disorders helped to establish that CUGEXP and CCUGEXP RNAs cause dominant RNA effects. While substantial data support RNA gain-of-function contributions to DM, recent discoveries, which fundamentally change our understanding of how disease-causing mutations are expressed, must also now be considered. First, much of the genome is bidirectionally transcribed, including the DM1 CTG'CAG expansion. Therefore, in addition to DM1 CUGEXP transcripts, mutant DM1 CAGEXP transcripts may also play a role in disease. Second, we recently discovered that the canonical rules of translation do not apply for CTG¿CAG repeat expansions and that CAG and CUG expansion transcripts can express homopolymeric expansion proteins in all three frames without an AUG start codon. This Repeat-Associated Non-ATG (RAN) translation is hairpin dependent, occurs without frameshifting or RNA editing and is observed in cell culture and DMpatient tissues. We propose to test the overall hypothesis that RAN translation contributes to DM disease pathogenesis. Our specific aims are to test the hypotheses: 1) that novel polymeric expansion proteins expressed by RAN translation accumulate in DM1 and DM2 brain and contribute to CNS pathology; 2) that RAN proteins are toxic independent of RNA gain of function effects; 3) that RAN translation can be blocked in vivo.

DM1和DM2中重复关联的非ATG翻译(项目1)-RANUM 成熟的翻译起始规则已被用作分子生物学的基石，以了解基因表达并预测导致疾病的突变的后果。对于强直性肌营养不良(DM)和其他微卫星扩张性疾病，位于预测编码区和非编码区的重复扩张(例如CAG或CTG)被认为是通过蛋白质获得或功能丧失或RNA功能获得机制而导致疾病。2001年，我们发现强直性肌营养不良2型(DM2)是由CNBP内含子CCTG*CAGG扩张引起的。DM1和DM2扩展突变的明显非编码位置以及两种疾病中RNA焦点的积累有助于确定CUGexp和CCUGEXP RNAs导致显性RNA效应。虽然大量数据支持RNA功能增益对糖尿病的贡献，但最近的发现从根本上改变了我们对致病突变如何表达的理解，现在也必须考虑这些发现。首先，基因组的大部分是双向转录的，包括DM1 CTG‘CAG扩增。因此，除了DM1 CUGexp转录本外，突变的DM1 CAGEXP转录本也可能在疾病中发挥作用。其次，我们最近发现，规范的翻译规则不适用于CTG？CAG重复扩展，并且CAG和CUG扩展转录本可以在没有Aug起始密码子的情况下在所有三个框架中表达均聚体扩展蛋白。这种重复相关的非ATG(RAN)翻译是发夹依赖的，没有移码或RNA编辑，在细胞培养和DM患者组织中观察到。我们建议检验RAN翻译在糖尿病发病机制中的作用这一总体假设。我们的具体目的是验证以下假设：1)由RAN翻译表达的新的聚合扩展蛋白在DM1和DM2脑中积累并有助于中枢神经系统的病理；2)RAN蛋白是有毒的，不依赖于RNA获得的功能效应；3)RAN翻译可以在体内被阻断。