Novel Role for Piwi/piRNA pathway in developmental robustness

Piwi/piRNA 通路在发育稳健性中的新作用

• 批准号: 8787737
• 负责人: VAMSI GANGARAJU
• 金额: $ 24.9万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-20 至 2016-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8787737
• 关键词: Affect; Apoptosis; Aubergine; Binding; Biochemical; Biogenesis; Biological Assay; Biological Models; Cell Nucleus; Cell physiology; Cells; Chromatin; Column Chromatography; Complex; DNA Fragmentation; Development; Developmental Biology; Disease; Drosophila genus; Embryo; Embryonic Development; Enhancers; Environment; Environmental Pollutants; Evolution; Eye Development; Female sterility; Foundations; Functional disorder; Future; Gene Expression Profile; Generations; Genes; Genetic; Genetic Screening; Genotype; Germ Lines; Goals; Human; Human Development; Industrial Waste; Inherited; Learning; Light; Maintenance; Mediating; Molecular; Molecular Chaperones; Mutagenesis; Organism; Pathway interactions; Peptides; Phosphorylation; Play; Population; Process; Proteins; Research; Resources; Role; Stem cells; Stress; Testing; Time; Toxic effect; Untranslated RNA; Variant; Work; abstracting; chromium hexavalent ion; combinatorial; dosage; epigenetic regulation; epigenetic variation; genetic analysis; genome-wide; human disease; in vivo; insight; novel; piRNA; pollutant; prevent; protein crosslink; research study; self-renewal; tool

Project Summary/Abstract: The long term goal of our proposal is to delineate the mechanisms by which Piwi/piRNA pathway normalizes phenotypic variation induced by severe environmental stress and inherent genotype variations. Canalization or developmental robustness provides a framework in which organisms resist displaying phenotypic variation in the face of combined genotype variations and severe environmental stress. Recent research has shown that Hsp90, a molecular chaperone, plays a critical role in canalization. Despite the known role for Hsp90, the lack of a detailed molecular mechanism underlying canalization has provoked great debate for decades. Our lab recently validated the existence of 'canalization' and uncovered a major molecular pathway involving Piwi, Hsp90 and Hop. Using a sensitized eye development assay, we showed that a reduction in the maternal dosage of Drosophila Piwi and Aubergine, which bind to novel germline-enriched small non-coding RNAs called piRNAs, induces phenotypic variations that can be fixed in a population and stably inherited in later generations. The study also showed that Piwi directly interacts with Hop and Hsp90 and functions in the same pathway as Hsp90 in suppressing phenotypic variations. Further, we demonstrate for the first time that Piwi becomes phosphorylated in an Hsp90 dependent manner, thus providing insights into how Hsp90 may modulate Piwi's function in canalization. Crucially, this study also revealed two related yet distinct Piwi/piRNA pathway-dependent mechanisms responsible for suppression of phenotypic variation: epigenetic silencing of inherent genotype variations and suppression of transposon-mediated mutagenesis. Our work revealed a framework of a pathway that suppresses phenotypic variation. Our working hypothesis is that Hsp90 and Hop modulate Piwi function via its phosphorylation which then modulates Piwi function in canalization. By further unraveling the inner workings of each step of this pathway, we aim to shed light on the mechanisms that mediate this very important, yet poorly understood cellular phenomenon. The aims of the proposal are to- 1) Discover new components that mediate and/or regulate Piwi function in canalization using genetic screens, 2) Unravel the biochemical mechanism of Piwi mediated epigenetic regulation in canalization and finally 3) Understand how Hsp90-Piwi/piRNA pathway counteracts environmental stress induced by industrial pollutants like hexavalent chromium. Piwi proteins are present from protozoans to humans with conserved functions in stem cell self-renewal and germ line maintenance. However their role in suppression of phenotypic variation is a novel function that requires further characterization. Unraveling the mechanism by which Piwi functions in canalization using Drosophila as a model system will provide the necessary context for understanding its roles in humans and learning how the dysfunction of this process might affect human development and cause diseases.

项目摘要/摘要： 我们提议的长期目标是描述Piwi/Pirna途径的机制 严重的环境应力和固有基因型变异引起的表型变异归一化。 携带或发育鲁棒性提供了一个框架，在该框架中，有机体抵抗显示 面对结合基因型变化和严重的环境应力的表型变化。最近的 研究表明，HSP90是一种分子伴侣，在口腔化中起着至关重要的作用。尽管已知 HSP90的作用，缺乏详细的分子机制，引发了巨大的辩论 几十年来。我们的实验室最近验证了“渠化”的存在，并发现了一个主要的分子 涉及Piwi，HSP90和Hop的路径。使用灵敏的眼睛发育测定法，我们表明了 果蝇piwi和Aubergine的母体剂量的降低，它们与新型种系结合 小型非编码RNA称为piRNA，诱导表型变异，可以固定在人群中，并且 后来稳定继承。该研究还表明，Piwi直接与HOP和HSP90相互作用 在抑制表型变化中与HSP90相同的途径中的功能。此外，我们为 第一次以Hsp90的方式磷酸化的第一次，从而提供了有关如何方式的见解。 HSP90可能会调节Piwi在管道中的功能。至关重要的是，这项研究还揭示了两个相关但不同的不同 PIWI/PIRNA途径依赖于抑制表型变异的机制：表观遗传学 固有基因型变化的沉默和转座子介导的诱变的抑制。我们的工作 揭示了抑制表型变化的途径的框架。我们工作的假设是 HSP90和Hop通过其磷酸化调节PIWI功能，然后调节PIWI功能 流管。通过进一步阐明该路径的每个步骤的内部运作，我们的目标是阐明 介导这种非常重要但知之甚少的细胞现象的机制。目的 提案是 - 1）发现使用介导和/或调节PIWI功能的新组件，并使用 遗传筛选，2）阐明PIWI介导的表观遗传学调节的生化机制 最后3）了解HSP90-PIWI/PIRNA途径如何抵消由 六价铬等工业污染物。 PIWI蛋白从原生动物到人类存在 干细胞自我更新和生殖线维护中的保守功能。但是它们在压制中的作用 表型变异是需要进一步表征的新功能。通过 哪种PIWI使用果蝇作为模型系统在载渠中起作用 将提供必要的背景 了解其在人类中的作用，并了解该过程的功能障碍如何影响人类 发展和引起疾病。