CONTROL OF LONG GENE EXPRESSION AS A NOVEL THERAPEUTIC APPROACH FOR RETT SYNDROME

项目概要： Rett综合征是女孩智力残疾的最常见遗传原因，其特征是： 神经发育迟缓、异常手臂运动、癫痫发作和自闭症谱系行为。已经 近十年来，Rett综合征是由MECP2基因突变引起的， 啮齿动物模型中的正常水平的MECP2，即使在症状发作后，也可以逆转大多数症状。虽然这 遗传洞察力为治疗提供了希望，神经元中MeCP2功能的令人难以置信的复杂性， 挑战了可行的治疗策略的发展。已知MeCP2高度富集于 神经元，并结合甲基化的DNA，但其对转录的微妙影响一直难以理解， 与Rett综合征表型的严重程度一致。我们的实验室最近进行了一项荟萃分析， 近十几项关于MeCP2调控基因的独立研究发现，MeCP2选择性地控制着 长基因的表达。该观察结果对MeCP 2具有高度特异性，并且在两种啮齿动物中均观察到。 模型和Rett综合征患者。MeCP 2在神经元中的高水平和神经元蛋白的倾向 大，由长基因编码，可以解释为什么MeCP2突变优先引起神经元 功能障碍我们的初步数据支持长基因失调在Rett发病机制中的作用。 由于直接用拓扑异构酶抑制剂使长基因表达正常化， 表型在体外和体内。在神经元中，拓扑异构酶的功能是在转录过程中解开DNA， 需要长基因的表达。MeCP 2和MeCP 2之间对长基因表达的相互控制 拓扑异构酶，以及初步的数据表明，这些蛋白质之间的物理相互作用，提高 几个重要的机制和治疗相关的问题，这是这个建议的重点。1)到 在Rett小鼠模型中表征拓扑异构酶抑制的细胞和行为效应 综合征，和2）表征MeCP2和拓扑异构酶之间的相互作用。所有这些 研究旨在为Rett综合征提供一种新的治疗策略， 通过直接控制拓扑异构酶的活性。

PROJECT SUMMARY: Rett syndrome is the most common genetic cause of intellectual disability in girls and is characterized by neurodevelopmental delay, abnormal arm movements, seizures, and autism spectrum behavior. It has been known for nearly a decade that Rett syndrome is caused by mutations in the MECP2 gene and that restoring normal levels of MECP2 in rodent models, even after symptom onset, can reverse most symptoms. While this genetic insight has provided hope for treatment, the incredible complexity of MeCP2 function in neurons has challenged the development of actionable therapeutic strategies. MeCP2 is known to be highly enriched in neurons and bind to methylated DNA, but its subtle effects on transcription have been difficult to understand and reconcile with the severity of Rett syndrome phenotypes. Our laboratory recently performed a meta-analysis of nearly a dozen independent studies of MeCP2-regulated genes and found that MeCP2 selectively controls the expression of very long genes. This observation is highly specific to MeCP2 and is observed in both rodent models and Rett syndrome patients. The high level of MeCP2 in neurons and the tendency for neuronal proteins to be large and encoded by long genes, may explain why MeCP2 mutations preferentially cause neuronal dysfunction. Our preliminary data supports a role of long gene misregulation in the pathogenesis of Rett syndrome because normalizing long gene expression directly with topoisomerase inhibitors improves Rett phenotypes in vitro and in vivo. In neurons, topoisomerases function to unwind DNA during transcription and are required for expression of long genes. The reciprocal control over long gene expression between MeCP2 and topoisomerase, as well as preliminary data demonstrating a physical interaction between these proteins, raise several important mechanistic and therapeutically relevant questions that are the focus of this proposal. 1) to characterize the cellular and behavioral effects of topoisomerase inhibition in the mouse model of Rett syndrome, and 2) to characterize the interaction between MeCP2 and topoisomerase. Together, these studies aim to inform a new therapeutic strategy for Rett syndrome focused on correcting long gene misregulation through direct control of topoisomerase activity.