How MeCP2 discriminates epigenetic marks is still a mystery

摘要 X染色体编码的‘甲基CpG结合蛋白2’(MECP2)在神经元中高表达。 并因其识别甲基-CpG(MCpG)表观遗传修饰而得名。这个 MeCP2在神经元和脑发育中的重要性被突显出来 基因突变导致了90%的自闭症谱系障碍Rett综合征的确诊病例。 最近的基因组研究提出了关于DNA全序列的重要问题 以及蛋白质结合的碱基修饰的类型。我们建议的研究旨在确定 核苷酸修饰类型DNA特异性识别的分子机制 序列和结合协同性，整合以介导MeCP2在染色质上的定位。我们的 该项目将能量分析和结构分析交织在一起，提出了定量组装研究 确定核苷酸修饰与局部和侧翼DNA序列的组合 赋予MeCP2高度特异性结合，MeCP2-DNA复合体的结构揭示IF 结合的目标站点之间存在差异，这决定了MeCP2如何与链接器竞争 组蛋白位于染色质上，随后定位于特定部位。我们的提案整合了 已建立的新的量化和结构方法，以探讨这一关键字如何具有约束力 染色质调节蛋白启动一系列分子相互作用，引导神经元 发展。

Abstract The X chromosome coded `Methyl CpG binding protein 2' (MECP2) is highly expressed in neuronal tissues and named for its recognition of the methyl-CpG (mCpG) epigenetic modification. The importance of MeCP2 to neuronal and brain development is highlighted by the fact that MeCP2 mutations cause >90% of the diagnosed cases of the autism spectrum disorder Rett syndrome. Recent genomic studies have raised important questions regarding the full range of DNA sequences and types of base modifications bound by the protein. Our proposed studies seek to determine the molecular mechanisms underlying specific recognition of the type of nucleotide modification, DNA sequence, and binding cooperativity that meld to mediate localization of MeCP2 on chromatin. Our project interleaves energetic and structural analyses proposing quantitative assembly studies to determine the combinations of nucleotide modification with local and flanking DNA sequences that confer high specificity MeCP2 binding, the structure of MeCP2 - DNA complexes to reveal if differences exist among the bound target sites, and determine how MeCP2 competes with linker histones on chromatin and subsequently localizes to specific sites. Our proposal integrates established and novel quantitative and structural approaches to explore how binding of this key regulatory protein to chromatin initiates a cascade of molecular interactions that guides neuronal development.