piRNA-mediated genome surveillance of germline transcripts

piRNA介导的种系转录本基因组监测

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/摘要转座子和病毒等入侵性外来核酸对所有生物体构成威胁，可能导致动物基因组不稳定和疾病，包括癌症和不育症。种系表达的小 RNA（称为 piRNA）与 PIWI 进化枝 Argonaute 蛋白相互作用，通过沉默转座元件充当基因组的守护者是我的长期目标。实验室的目标是解决小RNA介导的基因组防御的两个关键功能：（1）如何细胞如何区分“自身”和“非自身”核酸？（2）细胞如何通过表观遗传学沉默外源核酸？核酸世代相传。 piRNA 的一个惊人特征是其序列多样性，尽管它们在其中发挥着关键作用。转座子沉默，数以万计的 piRNA 表现出显着的序列多样性，并且不使用秀丽隐杆线虫作为模式生物，我们最近的研究表明存在多种转座子。 piRNA 提供生殖细胞识别各种外源核酸所需的序列复杂性值得注意的是，内源基因携带许可信号，赋予对 piRNA 的抗性。因此，我们的研究表明基因许可是防止沉默的关键机制。然而，基因许可信号的性质及其如何产生。反基因沉默仍然知之甚少。 piRNA 可以触发外源核酸几代人的表观遗传稳定沉默。基因沉默的遗传需要种系次级小RNA（22G-RNA）和染色质然而，只有一些外源核酸能够被 piRNA 稳定沉默。是什么决定了 piRNA 沉默的稳定性我们将检验竞争的假设。沉默和许可信号作用于 mRNA 之间决定了它们的表达状态，并且只有高度沉默状态的基因在几代人的时间里都处于稳定的沉默状态。总而言之，该提案将研究保护自身基因免受基因侵害的机制此外，我们将研究 Aim-1 中 piRNA 沉默的遗传是如何确定的。我们将采用遗传和生化方法来研究基因许可机制。 Aim-2，我们将调查许可和沉默途径如何竞争以确定在 Aim-3 中，我们将使用我们的 piRNA。这些研究将提供促进和抑制 piRNA 沉默的新因素。对小RNA介导的基因组防御系统以及对小RNA介导的基因组防御系统的基本见解表观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，我们的研究将揭示人类某些生育缺陷背后的分子机制。