Epigenetic control of metazoan transcription and pre-mRNA processing by histone PTMs

摘要 多细胞生物的发育和生存能力需要对基因表达进行稳健、准确的控制。 尽管控制这一过程的一些信息被编码在DNA中， “表观遗传学”（即独立于DNA序列）。重要的是，组蛋白翻译后修饰 （PTM）调节染色质的组织，并被广泛假设为表观遗传的重要载体 信息.直到最近，还不可能在多细胞真核生物中严格检验这一前提， 因为组蛋白基因簇的重复性质使它们难以进行遗传操作。然而，在这方面， 我们在果蝇中开发了一个创新的遗传平台，可以直接询问 特定组蛋白残基的功能。我们现在可以研究一个特定的组蛋白PTM的生物学功能， 将受体残基改变为不能被适当修饰的氨基酸。关键是，我们的方法 使该组蛋白基因的所有野生型拷贝能够被突变拷贝取代。在本提案中，我们 研究组蛋白H3 K36甲基化（H3 K36 me）在维持后生动物转录组保真度中的作用。 该提案的具体目标是利用我们的新平台直接分析复制- 转录、前mRNA加工和mRNA表达中的依赖性H3 K36和非依赖性H3.3K36组蛋白PTM 稳定这项研究对人类健康很重要，因为H3 K36的突变和进化上的 催化该残基修饰的保守酶（例如Set 2和NSD）涉及许多人类细胞中， 疾病，包括癌症。

Abstract The development and viability of multicellular organisms requires robust, accurate control of gene expression. Although some of the information governing this process is encoded within the DNA, much is passed on `epigenetically' (i.e. independent of the DNA sequence). Importantly, histone post-translational modifications (PTMs) modulate the organization of chromatin and are widely hypothesized to be essential carriers of epigenetic information. Until recently, it has been impossible to rigorously test this premise in multicellular eukaryotes, because the repetitive nature of histone gene clusters makes them difficult to manipulate genetically. However, we have developed an innovative genetic platform in Drosophila melanogaster that allows direct interrogation of the function of specific histone residues. We can now study the biological function of a specific histone PTM, by changing the acceptor residue to an amino acid that cannot be appropriately modified. Critically, our approach enables all wild-type copies of that histone gene to be replaced with mutant copies. In this proposal, we investigate the function of histone H3K36 methylation (H3K36me) in maintaining metazoan transcriptome fidelity. Specific aims for the proposal leverage our novel platform to directly assay the roles of both replication- dependent H3K36 and -independent H3.3K36 histone PTMs in transcription, pre-mRNA processing and mRNA stability. This research is important for human health because mutations in H3K36 and the evolutionarily conserved enzymes that catalyze modification of this residue (e.g. Set2 and NSD) are implicated in many human diseases, including cancer.