Complex interactions regulate histone methylation reprogramming at fertilization

复杂的相互作用调节受精时的组蛋白甲基化重编程

• 批准号: 9470211
• 负责人: Brandon Scott Carpenter
• 金额: $ 5.71万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9470211
• 关键词: Behavioral; Biological; Caenorhabditis elegans; Cells; ChIP-seq; Chromatin; Clinical Research; Complex; Congenital Abnormality; Craniofacial Abnormalities; DNA; Data; Defect; Development; Developmental Delay Disorders; Disease; Ectopic Expression; Embryo; Enzymes; Epigenetic Process; Event; Excision; Exhibits; Failure; Fertilization; Fluorescent in Situ Hybridization; Foundations; Gene Expression; Generations; Genes; Genetic Transcription; Germ Cells; Histones; Homologous Gene; Human; Intestines; KDM1A gene; Lead; Licensing; Lysine; Mammals; Methylation; Methyltransferase; Modeling; Morphology; Mus; Mutation; Nematoda; Oogenesis; Orthologous Gene; Patients; Phenocopy; Phenotype; Physiological; Process; Proteins; Quantitative Reverse Transcriptase PCR; Regulation; SETDB1 gene; Solid; Somatic Cell; Specificity; Tail; Testing; Tissues; Totipotency; Totipotent; Vulva; Work; base; cell type; chromatin modification; histone methylation; human disease; insight; knock-down; mutant; neuronal cell body; novel; prevent; programs; single molecule; sperm cell; transcriptome sequencing; zygote

PROJECT SUMMARY/ABSTRACT Cell fate is determined by gene expression, which in turn is determined by chromatin modifications that regulate access to DNA. Gametes are a highly specialized cell type, and as such, have a distinctive chromatin landscape. This necessitates that after fertilization, an epigenetic reprogramming event must occur to erase the gamete fate and allow the single-celled zygote to achieve totipotency. In this process, some chromatin modifications are erased by maternally-provided factors, while others are maintained to be propagated throughout its development. The failure to reprogram the chromatin landscape at fertilization is debilitating for development and may be a factor in human disease. A critical aspect of reprogramming is the addition and removal of methylation marks at histone protein tails, which regulate access to DNA (and therefore gene expression). In the nematode C. elegans, we have recently demonstrated that the histone 3 lysine 4 (H3K4) demethylase SPR-5 is required to remove H3K4 methylation (commonly considered a mark of active transcription), while the histone 3 lysine 9 (H3K9) methyltransferase MET-2 is subsequently required to add H3K9 methylation (considered a repressive mark). The progeny of mutants lacking both enzymes aberrantly accumulate H3K4 di-methylation at sperm genes, which correlates with the increased expression of these genes in somatic cells. These double mutant progeny have a severe developmental delay, along with defects in intestinal morphology, oogenesis, and vulva formation. In mice, the maternal loss of the SPR-5 homolog, LSD1/KDM1A, or the MET-2 homolog, SETDB1, leads to embryonic arrest by the 2-cell stage, demonstrating that histone modifiers are indispensable for vertebrate development. Furthermore, a recent clinical study showed that human patients with disruptions in LSD1 function exhibit developmental delay and craniofacial abnormalities. Together, these findings suggest a new disease paradigm where the inappropriate inheritance of histone methylation leads to developmental defects. Although chromatin reprogramming is essential for the proper regulation of development, we do not understand how the inappropriate propagation of histone methylation compromises normal development. The aims proposed here will begin to decipher this mechanism by AIM 1) characterizing the failure to distinguish between a germline or somatic fate, AIM 2) determining the mechanism that allows the misexpression of germline genes in somatic tissues, and AIM 3) examining how the inappropriate expression of germline genes in specific tissues leads to physiological defects. Human studies have indicated that the inappropriate inheritance of histone methylation between generations might be a novel mechanism of disease. Our work will provide basic insight into this new mechanism to generate a solid foundation for later translational efforts. !

项目概要/摘要 细胞命运由基因表达决定，而基因表达又由染色质修饰决定， 调节 DNA 的获取。配子是一种高度特化的细胞类型，因此具有独特的染色质 景观。这使得受精后必须发生表观遗传重编程事件来消除 配子命运并允许单细胞受精卵实现全能性。在此过程中，一些染色质 修饰被母体提供的因素消除，而其他修饰则维持传播 在其整个发展过程中。受精时染色质景观的重新编程失败正在使人衰弱 发育并可能是人类疾病的一个因素。重编程的一个关键方面是添加和 去除组蛋白尾部的甲基化标记，这些标记调节 DNA 的获取（因此基因 表达）。在线虫中，我们最近证明组蛋白 3 赖氨酸 4 (H3K4) 需要去甲基化酶 SPR-5 来去除 H3K4 甲基化（通常被认为是活性的标志） 转录），而组蛋白 3 赖氨酸 9 (H3K9) 甲基转移酶 MET-2 随后需要添加 H3K9 甲基化（被认为是抑制标记）。异常缺乏这两种酶的突变体的后代 在精子基因处积累 H3K4 二甲基化，这与这些基因的表达增加相关 体细胞中的基因。这些双突变后代具有严重的发育迟缓以及缺陷 肠道形态、卵子发生和外阴形成。在小鼠中，母体失去 SPR-5 同源物， LSD1/KDM1A 或 MET-2 同源物 SETDB1 导致胚胎在 2 细胞阶段停滞，证明 组蛋白修饰剂对于脊椎动物的发育是不可或缺的。此外，最近的一项临床研究 研究表明，LSD1 功能受损的人类患者表现出发育迟缓和颅面畸形 异常。总之，这些发现提出了一种新的疾病范式，其中不适当的遗传 组蛋白甲基化会导致发育缺陷。尽管染色质重编程对于 发育的适当调节，我们不明白组蛋白的不适当增殖是如何发生的 甲基化会损害正常发育。这里提出的目标将开始破译这个机制 通过 AIM 1) 表征无法区分种系命运或体细胞命运，AIM 2) 确定 允许体细胞组织中种系基因错误表达的机制，以及 AIM 3) 检查如何 种系基因在特定组织中的不适当表达会导致生理缺陷。人类研究 表明组蛋白甲基化在代际间的不适当遗传可能是一个新奇的现象 发病机制。我们的工作将为这种新机制提供基本的见解，以产生可靠的 为以后的翻译工作奠定基础。 ！