Specific Chemical Probes for Histone Demethylases

描述(由申请人提供)：共价组蛋白修饰被认为是最重要的表观遗传现象之一。组蛋白去甲基酶是最近发现的一类组蛋白修饰酶。到目前为止，已经鉴定了十几个含有Jumonji C结构域的组蛋白去甲基酶(JHDM)。它们可以在所有甲基化状态下修饰组蛋白上许多不同位置的赖氨酸残基。它们通常表现出组织特异性的表达，并在各种细胞过程中发挥关键作用，如 如基因表达、减数分裂和胚胎干细胞自我更新。此外，一些JHDM，如JMJD2C，与人类疾病有关，如智力低下和癌症。然而，JHDM的细胞功能和底物范围仍然不清楚。目前，研究JHDM及其细胞功能的研究工具非常有限。目前还不存在针对JHDM的高活性和特定的化学探针。各种JHDM亚型的统一生化分析也不发达。在这项计划中，我们计划开发一系列针对JHDM的特异性化学探针，包括高活性和特异性的细胞探针、荧光小分子探针和专门针对H3K9-JHDMS的高度功能化的多肽探针。该细胞探针可用于研究JHDMS的细胞功能以及广泛的生物学过程和疾病过程中的组蛋白甲基化动力学。该荧光探针正被应用于开发一种基于荧光偏振的分析方法，它不仅使我们能够验证我们的二价抑制剂设计，而且还提供了一种统一的JHDM生化分析方法来分析JHDM抑制剂的异构体特异性。多肽探针不仅对研究JHDM的底物范围很重要，而且对提供有关组蛋白串扰的有价值的信息也很重要。此外，我们在这里开发的策略可以应用于发现修饰H3K79me3和H4K20me3的新型JHDM，最终导致组蛋白甲基化及其相应JHDM的系统图谱。此外，这些探针还可以用来验证JHDMS作为癌症等疾病的潜在新治疗靶点的有效性，并可以作为进一步开发这些疾病的新疗法的先导化合物。

DESCRIPTION (provided by applicant): Covalent histone modifications are considered one of the most important epigenetic phenomena. Histone demethylases are the most recently discovered class of histone-modifying enzymes. Over a dozen Jumonji C domain-containing histone demethylases (JHDMs) have been characterized so far. They can modify lysine residues at many different positions on histone proteins at all methylation states. They often display tissue-specific expression and play critical roles in a variety of cellular processes, such as gene expression, meiosis, and embryonic stem cell self-renewal. In addition, several JHDMs such as JMJD2C have been associated with human diseases, such as mental retardation and cancers. However, the cellular functions and the substrate scope of JHDMs are still unclear. Currently, research tools to study JHDMs and their cellular functions are very limited. Highly active and specific chemical probes for JHDMs currently do not exist. A uniform biochemical assay for various JHDM isoforms is also underdeveloped. In this proposal, we plan to develop a series of specific chemical probes for JHDMs, including a highly active and specific cellular probe, a fluorescent small-molecule probe, and a highly functionalized peptidic probe specifically targeting H3K9-JHDMs. The cellular probe can be used for the studies of the cellular functions of JHDMs and histone methylation dynamics in a wide range of biological processes and disease processes. The fluorescent probe is being applied to develop a fluorescence polarization-based assay, which will not only enable us to validate our bivalent inhibitor design, but also provide a uniform JHDM biochemical assay to analyze isoform specificity of JHDM inhibitors. The peptidic probe is important not only to study the substrate scope of JHDMs, but also to provide valuable information on the histone crosstalk. In addition, the strategy we develop here can be applied to the discovery of novel JHDMs that modify H3K79me3 and H4K20me3, eventually leading to a systematic map of histone methylations and their corresponding JHDMs. Furthermore, these probes can also be used to validate JHDMs as potential novel therapeutic targets for diseases such as cancers, and can serve as lead compounds for further development of novel therapeutics for these diseases.