Epigenetic Mechanisms of Gene Regulation in Long-Term Memory Formation

描述（由申请人提供）：新获得的记忆通过称为记忆巩固的过程变得稳定，可长期储存，这需要从头基因表达。在这一过程中，基因转录的中断会特别阻碍长期记忆的形成。脑源性神经营养因子（BDNF）已被证明在长期记忆的巩固或储存中发挥重要作用。然而，很少有人知道在大脑中的BDNF转录的外显子特异性的调节，以及这种水平的BDNF基因调节功能在记忆形成的过程中。这项应用的主要科学目标是确定BDNF基因表达变化的表观遗传调节机制，这些变化有助于稳定长期记忆。这项授权的基本假设是，异常的表观遗传标记，如组蛋白的翻译后修饰，DNA甲基化和转录因子激活在记忆形成中的外显子特异性BDNF基因调控中发挥作用。本申请的指导阶段将使用多种方法的组合来剖析记忆巩固过程中外显子特异性BDNF基因调控的表观遗传机制，包括测量与外显子特异性BDNF转录物相关的DNA甲基化，使用染色质免疫印迹（ChIP）技术分析组蛋白、甲基CpG结合蛋白2和BDNF启动子区组蛋白脱乙酰酶的翻译后修饰水平，并研究DNMT抑制是否改变记忆巩固过程中BDNF外显子特异性mRNA的表达。在该项目的第一个独立阶段的目标，NMDA受体（NMDA-R）激活的BDNF基因的表观遗传调控的作用将进行分析，使用新技术的组合，以评估海马BDNF转录的细胞类型特异性染色质重塑。第二个独立阶段的目标是评价NMDA-R介导的转录因子核因子κ B（NF-κ B）募集到DNA内BDNF调控元件的功能影响，并鉴定NF-κ B DNA结合复合物在调节BDNF基因染色质重塑中的作用。该应用程序探讨了BDNF基因调控的表观遗传机制在长期记忆形成中的作用，重点是确定可能导致药物发现和开发的分子机制，以干预精神障碍的临床特征。事实上，表观遗传机制与精神疾病的病因学有关，如精神分裂症、抑郁症和双相情感障碍。通过了解记忆形成过程中以及潜在的精神障碍中涉及脑源性神经营养因子基因表达的表观遗传调节机制，参与这一过程的其他基因可能会落入一个共同的生化途径，其中疾病干预是可能的。

DESCRIPTION (provided by applicant): A newly acquired memory becomes stable for long-term storage through a process known as memory consolidation, which requires de novo gene expression. Disruption of gene transcription during this process specifically blocks long-term memory formation. The brain-derived neurotrophic factor (BDNF) has been shown to play an essential role in the consolidation or storage of long-term memory. However, little is known about the regulation of exon-specific BDNF transcripts in the brain and how this level of BDNF gene regulation functions in the process of memory formation. The major scientific goal of this application is to identify epigenetic-regulating mechanisms for BDNF gene expression changes that serve to stabilize long-term memory. The underlying hypothesis of this grant is that aberrant epigenetic markings such as post- translational modification of histones, DNA methylation and transcription factor activation plays a role in exon-specific BDNF gene regulation in memory formation. The mentored phase of this application will dissect epigenetic mechanisms of exon-specific BDNF gene regulation during memory consolidation using a combination of approaches including measuring DNA methylation associated with exon-specific BDNF transcripts, using chromatin immunoprecipition (ChIP) technology to analyze levels of post-translational modification of histones, methyl CpG binding protein 2, and histone deacetylases at BDNF promoter regions, and investigating whether DNMT inhibition alters BDNF exon-specific mRNA expression during memory consolidation. During the first independent phase aim of the project, the role for NMDA receptor (NMDA-R) activation in the epigenetic regulation of the BDNF gene will be analyzed using a combination of novel technologies to assess cell-type specific chromatin remodeling of BDNF transcripts in hippocampus. The second independent phase aim will evaluate the functional impact of NMDA -R-mediated recruitment of the transcription factor nuclear factor kappa B (NF-KB) to BDNF regulatory elements within DNA and to identify the role of the NF-KB DNA-binding complex in the regulation of chromatin remodeling of the BDNF gene. This application explores the role of epigenetic mechanisms of BDNF gene regulation in long-term memory formation with a focus on identifying molecular mechanisms that may lead to drug discovery and development to intervene in the clinical features of mental disorders. Indeed, epigenetic mechanisms have been implicated in the etiology of mental illnesses, such as schizophrenia, depression, and bipolar disorder. Through the understanding of epigenetic-regulating mechanisms involved in BDNF gene expression during memory formation and potentially in mental disorders, other genes involved in this process may fall into a common biochemical pathway where disease intervention is possible.