piRNA-mediated genome surveillance of germline transcripts

piRNA介导的种系转录本基因组监测

• 批准号: 10557913
• 负责人: Heng-Chi Lee
• 金额: $ 33.57万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10557913
• 关键词: Address; Animals; Antibodies; Antigens; Autoimmunity; Binding; Biochemical; Biochemistry; Biological Assay; Caenorhabditis elegans; Cell Nucleus; Cells; Cellular biology; Chromatin; Cytoplasmic Granules; DNA; DNA Transposable Elements; Data; Defect; Deposition; Detection; Development; Disease; Elements; Engineering; Epigenetic Process; Exhibits; Fertility Disorders; Gene Expression; Gene Expression Regulation; Gene Silencing; Generations; Genes; Genetic; Genetic Screening; Genome; Genome Stability; Genomic Instability; Genomics; Germ; Germ Cells; Goals; Human; Immune system; Infertility; Inherited; Investigation; Knowledge; Laboratories; Length; Licensing; Licensing Factor Gene; Logic; Maintenance; Malignant Neoplasms; Mediating; Messenger RNA; Modeling; Molecular; Mus; Mutation; Nature; Nuclear; Nucleic Acids; Organism; Pathway interactions; Periodicals; Play; Positioning Attribute; Process; Production; Protein Family; Proteins; RNA; Reporter; Repression; Research; Resistance; Retroviridae; Role; Science; Selfish DNA; Signal Transduction; Site; Small RNA; System; Testing; Transcript; Virus; chromatin modification; genetic analysis; insight; model organism; mutant; novel; nucleic acid stability; piRNA; prevent; tool

PROJECT SUMMARY / ABSTRACT Invasive foreign nucleic acids such as transposons and viruses pose a threat to all organisms, potentially causing genome instability and diseases including cancer and infertility. In animals, germline-expressed small RNAs known as piRNAs interact with PIWI-clade Argonaute proteins and act as a guardian of the genome by silencing transposable elements. The long-term goal of my laboratory is to address two critical functions of small RNA-mediated genome defense: (1) How do cells distinguish “self” from “non-self” nucleic acids? (2) How do cells epigenetically silence foreign nucleic acids for generations. One astonishing feature of piRNAs is their sequence diversity. Despite their critical role in transposon silencing, tens of thousands of piRNAs exhibit remarkable sequence diversity and do not map to transposons. Using C. elegans as a model organism, our recent research suggests diverse piRNAs provide sequence complexity needed for germ cells to recognize various foreign nucleic acids. Remarkably, endogenous genes carry licensing signals that confer resistance to piRNA silencing. Therefore, our research suggests gene-licensing as a key mechanism that prevents endogenous genes from silencing. However, the nature of the gene-licensing signals and how they counter gene silencing remain poorly understood. piRNAs can trigger epigenetically stable silencing of foreign nucleic acids for generations. The inheritance of gene silencing requires germline secondary small RNAs (22G-RNAs) and chromatin modifications. However, only some foreign nucleic acids are stably silenced by piRNAs. It is unknown what determines the stability of piRNA silencing. We will test the hypothesis that the competition between silencing and licensing signals act on mRNAs determines their expression states, and only genes of strongly silenced states are stably silenced for generations. Taken together, this proposal will investigate the mechanisms that protect self genes from gene silencing. In addition, we will examine how the inheritance of piRNA silencing is determined. In Aim-1, we will adapt genetic and biochemical approaches to investigate the mechanism of gene licensing. In Aim-2, We will investigate how the licensing and silencing pathways compete to determine the expression or silencing of germline transcripts over generations. In Aim-3 we will use our piRNA reporter to identify novel factors that promote and inhibit piRNA silencing. These studies will provide fundamental insights into the small RNA-mediated genome defense system, as well as into the molecular basis of epigenetic inheritance. As PIWI mutants exhibit fertility defects in various animals, our research will uncover the molecular mechanism underlying some fertility defects in humans.

项目摘要 /摘要 侵入性外国核酸（例如转座子和病毒）对所有生物构成威胁， 可能导致基因组不稳定性和包括癌症和不育症在内的疾病。在动物中 种系表达的小RNA被称为piRNA与Piwi-Clade Argonaute蛋白相互作用 通过沉默可转移元素来充当基因组的监护人。我的长期目标 实验室将解决小RNA介导的基因组防御的两个关键功能：（1）如何如何 细胞将“自我”与“非自我”核酸区分开？ （2）细胞如何表观遗传沉默异物 几代人的核酸。 PIRNA的一个惊人特征是它们的序列多样性。尽管它们在 转座子沉默，成千上万的piRNA暴露了显着的序列多样性，不要 地图到转座。我们最近的研究表明，使用秀丽隐杆线虫作为模型生物体， PIRNA提供了生殖细胞识别各种外国核所需的序列复杂性 酸。值得注意的是，内源性基因带有许可信号，该信号是对PIRNA的抗拒 沉默。因此，我们的研究表明，基因许可作为阻止的关键机制 沉默中的内源基因。但是，基因许可信号的性质及其如何 反基因沉默仍然很少理解。 PIRNA可以世代相传外核酸的表观遗传稳定的沉默。这 基因沉默的遗传需要种系次级小RNA（22G-RNA）和染色质 修改。但是，只有一些外国核酸被PIRNA稳定地沉默。这是未知的 什么决定了pirna沉默的稳定性。我们将检验竞争的假设 在沉默和许可信号上，关于mRNA的法案决定其表达状态，仅 世代相传的强烈沉默状态基因稳定地沉默。 综上所述，该建议将研究保护自我基因免受基因的机制 沉默。此外，我们将研究如何确定piRNA沉默的遗传。在AIM-1中， 我们将适应遗传和生化方法来研究基因许可的机制。在 AIM-2，我们将调查许可和沉默途径如何竞争以确定 世代相传种系转录本的表达或沉默。在AIM-3中，我们将使用我们的Pirna 记者确定促进和抑制pirna沉默的新因素。这些研究将提供 对小的RNA介导的基因组防御系统的基本见解，以及 表观遗传遗传的分子基础。由于Piwi突变体在各种动物中表现出生育缺陷，因此 我们的研究将揭示人类某些生育能力缺陷的分子机制。