Regulation of SMN and Identification of its Downstream Target

SMN的调控及其下游目标的识别

• 批准号: 8449148
• 负责人: Judith A Steen
• 金额: $ 43.32万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8449148
• 关键词: 2 year old; 3' Untranslated Regions; APC2 gene; Affect; Axon; Binding; Biogenesis; Biology; Brain Stem; Candidate Disease Gene; Caspase; Cell Cycle; Cell Nucleus; Cessation of life; Co-Immunoprecipitations; Complex; Data; Defect; Disease; Elements; Genes; Genetic; Growth; Growth Factor; Half-Life; Human; Indium; Individual; Infant Mortality; Knockout Mice; Kugelberg-Welander Disease; Length; Maintenance; Maps; Mass Spectrum Analysis; Measures; Messenger RNA; Modeling; Molecular Profiling; Motor Neurons; Muscle; Mutate; Mutation; Neurites; Neurons; Pathology; Pathway interactions; Patients; Phenotype; Play; Proteins; Proteomics; RNA; RNA Splicing; RNA analysis; RNA-Binding Proteins; Regulation; Respiratory Failure; Role; SMN1 gene; SMN2 gene; Severity of illness; Site; Spinal; Spinal Cord; Spinal Muscular Atrophy; Testing; Therapeutic Intervention; Transcript; Translations; Ubiquitination; United States; Western Blotting; Work; anaphase-promoting complex; axon growth; crosslink; deprivation; disease-causing mutation; infant death; insight; interest; loss of function; mRNA Expression; member; multicatalytic endopeptidase complex; neuron apoptosis; neuronal survival; novel; overexpression; prevent; protein complex; protein degradation; research study; survival motor neuron gene; synaptic function; synaptogenesis; therapy design; ubiquitin-protein ligase

TITLE: Regulation of SMN stability and identification of its downstream targets SUMMARY Spinal Muscular Atrophy (SMA), a disease caused by the mutations of Survival Motor Neuron 1 (SMN1) gene, is the most common genetic cause of infant mortality. Humans have two copies of the SMN gene, the telomeric SMN1, which encodes for a full-length form (FL-SMN), and the centromeric SMN2, which encodes primarily for a rapidly-degraded truncated form (SMN7) as well as the full-length form. In the most severe form, Type 1 SMA, there are 1 or 2 copies of the SMN2 gene, and patients die within 2 years of age due to respiratory failure. Patients with more copies of the SMN2 gene, however, manifest a less severe form of SMA (Type III SMA). SMA occurs due to decreased amount of FL-SMN protein in spinal motor neurons. Therefore, much of the effort for therapeutic interventions in SMA has focused on increasing the level of FL-SMN protein products. Our preliminary results show that SMN is found in a complex containing an E3 ubiquitin ligase the Anaphase- Promoting Complex (APC) and HuD, a RNA binding protein. The APC targets proteins to the proteasome for degradation whereas HuD stabilizes mRNAs. Furthermore, evidence indicates a role for APC in neuronal survival, axonal growth, and synaptic function, and HuD is involved in the maturation and maintenance of neurons. We also know from previous studies that SMN may be necessary for the transport, stability and/or translation of certain mRNAs in neurites. These data together prompted us to formulate a working model in which: 1) ubiquitination by APC regulates the stability and/or function of SMN or other members of the SMN complex and 2) the putative HuD-SMN-associated mRNAs in axons are important for the growth and survival of motor neurons. In the first part of this proposal, we will investigate the role of APC in regulation of SMN stability and function. We will first characterize the interaction between APC and SMN in neurons. Then, we will investigate the effect of inhibiting the APC-SMN interaction on the function, stability, localization, of SMN protein. In the second part, we will focus on one axonal SMN target mRNA which is likely to play a role in axon outgrowth. Since there is a tight correlation between the amount of FL-SMN and the severity of disease, understanding the interaction between APC and SMN as well as elucidating the downstream targets of SMN will provide important insights into the biology of SMA and has the potential to generate new treatment options for this disease.

标题： SMN稳定性调节及其下游靶标的识别 概括 脊髓性肌萎缩症（SMA）是一种由运动神经元存活1（SMN1）基因突变引起的疾病， 是婴儿死亡最常见的遗传原因。人类有两个 SMN 基因拷贝，即端粒 SMN1，编码全长形式（FL-SMN），着丝粒 SMN2，主要编码 快速降解的截短形式 (SMN 7) 以及全长形式。最严重的形式是 1 型 SMA，有1~2个SMN2基因拷贝，患者2岁内因呼吸道疾病死亡 失败。然而，具有更多 SMN2 基因拷贝的患者表现出不太严重的 SMA（III 型 SMA）。 SMA 的发生是由于脊髓运动神经元中 FL-SMN 蛋白数量减少所致。因此，很多 SMA 治疗干预的重点是提高 FL-SMN 蛋白产品的水平。 我们的初步结果表明，SMN 存在于含有 E3 泛素连接酶的复合物中。 促进复合物 (APC) 和 HuD（一种 RNA 结合蛋白）。 APC 将蛋白质靶向蛋白酶体 降解，而 HuD 稳定 mRNA。此外，有证据表明 APC 在神经元中发挥作用 HuD 参与生存、轴突生长和突触功能的成熟和维持 神经元。我们还从之前的研究中得知，SMN 可能对于运输、稳定性和/或 神经突中某些 mRNA 的翻译。这些数据共同促使我们制定了一个工作模型 其中：1) APC 的泛素化调节 SMN 或 SMN 其他成员的稳定性和/或功能 复合体和 2) 轴突中假定的 HuD-SMN 相关 mRNA 对于生长和存活很重要 运动神经元。在本提案的第一部分，我们将研究 APC 在 SMN 监管中的作用 稳定性和功能。我们将首先描述神经元中 APC 和 SMN 之间的相互作用。那么，我们将 研究抑制 APC-SMN 相互作用对 SMN 功能、稳定性、定位的影响 蛋白质。在第二部分中，我们将重点关注一种可能在轴突中发挥作用的轴突 SMN 靶标 mRNA 生长出来的。由于 FL-SMN 的量与疾病的严重程度之间存在紧密相关性， 了解APC和SMN之间的相互作用以及阐明SMN的下游靶点 将为 SMA 的生物学提供重要见解，并有可能产生新的治疗方案 对于这种疾病。