Investigation of roles and mechanisms of DNA and histone modification networks in trans-generational epigenetic inheritance

DNA和组蛋白修饰网络在跨代表观遗传中的作用和机制研究

• 批准号: 9753026
• 负责人: Yang Shi
• 金额: $ 40.36万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-19 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9753026
• 关键词: Address; Adenine; Adenosine; Affect; Angelman Syndrome; Animal Model; Architecture; Attention; Binding Proteins; Biochemical; CRISPR/Cas technology; Caenorhabditis elegans; Cell physiology; ChIP-seq; Chemicals; Chromatin; Chromatin Structure; Cytosine; DNA; DNA Methylation; DNA Modification Process; Development; Disease susceptibility; Engineering; Enzymes; Epigenetic Process; Event; Female; Fertility; Foundations; Gene Expression; Gene Expression Regulation; Generations; Genetic Transcription; Genome Stability; Genomics; Germ Cells; Heritability; Histone H3; Histones; Homologous Gene; Human; In Vitro; Infertility; Inheritance Patterns; Inherited; Investigation; KDM1A gene; Length; Longevity; Lysine; Macromolecular Complexes; Malignant Neoplasms; Mammals; Mass Spectrum Analysis; Mediating; Methylation; Methyltransferase; Modification; Molecular; Obesity; Organism; Outcome; Phenotype; Play; Positioning Attribute; Proteins; Reader; Regulation; Role; Site; Sterility; System; Testing; Work; epigenetic memory; epigenetic regulation; epigenetic therapy; experimental study; fascinate; genome-wide; genome-wide analysis; histone modification; human disease; in vivo; insight; male; mutant; novel; programs; protein purification; telomere; trait; transgenerational epigenetic inheritance; transmission process

Summary: Most heritable information is transmitted by DNA, following Mendelian inheritance patterns; but some traits, such as longevity, fertility, disease susceptibility, and obesity, can be inherited non-genetically in several model organisms. The underlying molecular mechanisms of trans-generational epigenetic transmission remain unclear, but chromatin changes may play a role. Chromatin is composed of DNA and histone proteins, both of which are extensively chemically modified. These modifications are recognized by so called “reader” proteins, and they regulate chromatin structure and function, together with the enzymes that add and remove modification marks. Previous work identified a fascinating trans-generational epigenetic inheritance phenomenon in C. elegans, whereby worms lacking spr-5, the human homolog of the histone H3K4me2 demethylase LSD1, do not exhibit sterility initially; however, successive generations lacking spr-5 display increasing infertility concomitant with global accumulation of H3K4me2. This progressive phenotype can be reversed by introducing a single copy of SPR-5, but how this epigenetic memory is transmitted across generations is still unknown. In many species DNA methylation at the 5th position of cytosine (5mC) is well- documented as one of the major regulatory mechanisms of epigenetic inheritance. However, 5mC is absent in C. elegans, as is the enzymatic machinery that installs methylation on cytosine, raising the question as to how epigenetic inheritance is accomplished in species such as C. elegans that lack cytosine methylation. Our recent work has uncovered an exciting new facet to epigenetic inheritance in C. elegans: we have discovered a novel DNA modification-- methylation of adenine at the 6th position (6mA)-- and have also identified the enzymes responsible for adding and removing this mark. Interestingly, this modification accumulates over the generations in mutants lacking SPR-5, paralleling the increase in H3K4me2 and the decrease in fertility, suggesting that 6mA participates in a network of epigenetic interactions that regulate germline immortality. However, little is known about how 6mA is regulated, its mechanism of accumulation in spr-5 mutants, or its role in regulating gene expression or chromatin architecture in a manner that affects fertility in spr-5 mutants. In this application, we will investigate the genome-wide distribution of 6mA (paying special attention to its accumulation in late-generation spr-5 worms) and its effects on transcription in wild-type and spr-5 mutants; determine the sites of action of the 6mA methyltransferase and demethylase as well as their means of regulation, particularly in the context of maintaining fertility; and finally identify proteins that recognize 6mA to promote downstream events such as appropriate germline gene expression programs. The proposed studies are built upon the recent discovery of 6mA and are expected to elucidate an unappreciated mode of gene regulation, providing insight into mechanisms that control epigenetic inheritance and informing studies in other species.

总结： 大多数遗传信息是通过DNA传递的，遵循孟德尔遗传模式;但有些特征， 例如长寿、生育力、疾病易感性和肥胖，可以在几种模型中非遗传地遗传 有机体跨代表观遗传传递的潜在分子机制仍然存在 尚不清楚，但染色质变化可能起作用。染色质由DNA和组蛋白组成，两者都是 它们被广泛地化学修饰。这些修饰被所谓的“阅读器”蛋白识别， 它们调节染色质的结构和功能， 修改标记。以前的工作确定了一个迷人的跨代表观遗传 现象C.秀丽线虫，其中蠕虫缺乏组蛋白H3 K4 me 2的人类同源物spr-5 脱甲基酶LSD 1最初不显示不育性;然而，缺乏spr-5显示的连续世代 增加不孕症伴随H3 K4 me 2的全面积累。这种进行性表型可以是 通过引入SPR-5的单个拷贝来逆转，但是这种表观遗传记忆是如何通过 几代人都不知道。在许多物种中，胞嘧啶第5位（5 mC）的DNA甲基化是很好的- 作为表观遗传的主要调节机制之一。然而，5 mC是缺席， C.这是一种酶机制，在胞嘧啶上安装甲基化，提出了一个问题， 表观遗传在诸如C.缺少胞嘧啶甲基化的线虫。 我们最近的工作揭示了一个令人兴奋的新方面，表观遗传遗传在C。Elegans：我们有 发现了一种新的DNA修饰--第6位腺嘌呤的甲基化（6 mA）--并且还发现了一种新的DNA修饰--第6位腺嘌呤的甲基化（6 mA）-- 确定了负责添加和删除该标记的酶。有趣的是，这种改变 在缺乏SPR-5的突变体中，H3 K4 me 2的增加与H3 K4 me 2的增加平行， 生育力下降，表明6 mA参与了一个表观遗传相互作用的网络，调节 生殖细胞永生然而，关于6 mA是如何调节的，其在细胞中积累的机制， SPR-5突变体，或其在调节基因表达或染色质结构中的作用， SPR-5突变体的育性。在本申请中，我们将研究6 mA的全基因组分布（支付 特别注意其在晚代Spring-5蠕虫中积累）及其对野生型中转录的影响 和spr-5突变体;确定6 mA甲基转移酶和脱甲基酶的作用位点，以及 它们的调节方式，特别是在维持生育力的背景下;最后确定 识别6 mA以促进下游事件，例如适当的种系基因表达程序。的 建议的研究是建立在最近发现的6 mA，并有望阐明一个未被重视的 基因调控模式，提供控制表观遗传遗传和告知机制的见解 研究其他物种。