Investigation of MeCP2 Function in Rett Syndrome

描述（由申请人提供）：编码甲基CpG结合蛋白2 （MeCP2）基因的新生突变是Rett综合征（RTT）的主要原因，Rett综合征是一种x连锁显性神经发育障碍。Mecp2是一种染色质相关蛋白，长期以来一直被认为是甲基化DNA的非特异性转录抑制因子。然而，最近的数据表明，Mecp2可以与特定的转录调控因子相互作用，从而改变上下文基因的表达。与RTT患者明显的神经表型一致，新出现的证据表明Mecp2活性与神经元功能之间存在密切关联。在哺乳动物神经系统中，Mecp2在有丝分裂后的神经元中表达最高，其中新发现的剪接变体Mecp2e1是主要的转录物。Mecp2突变引起的表型和神经病理的相似性表明，Mecp2的神经元功能在人和小鼠之间是保守的。本课题的目的是为了更好地了解Mecp2在培养的神经细胞细胞核中的调控和活性，并确定突变和丝氨酸磷酸化如何影响其功能。这项工作将使用活细胞成像方法来检查细胞核中Mecp2的移动性，并探索突变、染色质重塑和磷酸化对染色质结合的影响。我们将具体表征一个新发现的剪接变异体的蛋白质是相关的亚型在疾病。我们还将描述神经生长因子和靶神经支配在调节Mecp2表达和交感神经元功能中的作用，并确定Mecp2缺乏如何影响交感神经元对生理信号的反应能力。总之，这些研究应该回答关于交感神经元通过同种异构体特异性表达和翻译后修饰调节Mecp2功能的方式的基本问题。这些研究将有助于阐明Mecp2蛋白的调控方式，并测试导致疾病的突变如何影响该蛋白的功能。长期目标是了解RTT患者神经系统功能障碍的发病机制，并确定调节系统以潜在地改善功能和开发靶向治疗的方法。

DESCRIPTION (provided by applicant): De novo mutations in the gene encoding methyl CpG binding protein 2 (MeCP2) are the primary cause of Rett Syndrome (RTT), an X-linked dominant neurodevelopmental disorder. Mecp2 is a chromatin-associated protein that has long been considered to be a non-specific transcriptional repressor of methylated DNA. However, recent data indicate that Mecp2 can interact with specific transcriptional regulators to alter contextual gene expression. Consistent with the pronounced neurological phenotype in RTT patients, emerging evidence suggests a close association between Mecp2 activity and neuronal function. In the mammalian nervous system, Mecp2 expression is highest in postmitotic neurons, where a newly identified splice variant, Mecp2e1, is the predominant transcript. Similarities in phenotype and neuropathology caused by mutations in Mecp2 suggest that the neuronal function of Mecp2 is conserved between humans and mice. The goals of this proposal are to better understand the regulation and activity of Mecp2 in the nucleus of cultured neuronal cells and determine how mutation and serine phosphorylation affect its function. The work proposed will use live cell imaging approaches to examine the mobility of Mecp2 in the nucleus and explore the consequences of mutation, chromatin remodeling and phosphorylation on chromatin binding. We will specifically characterize a newly identified splice variant of the protein that is the relevant isoform in the disease. We will also characterize the role of nerve growth factor and target innervation in regulation of Mecp2 expression and function in sympathetic neurons and determine how Mecp2 deficiency affects the ability of a sympathetic neuron to respond to physiologic cues. Together these studies should answer fundamental questions about the ways that sympathetic neurons modulate Mecp2 function, through isoform specific expression and post-translational modification. These studies will help clarify the way that the Mecp2 protein is regulated and test the ways in which disease causing mutations affect the protein's function. The long term goals are to understand the pathogenesis of the dysfunction of the nervous system in patients with RTT and determine ways that the system can be modulated to potentially improve function and develop targeted therapies.