Genetic and Molecular Dissection of Meiotic Silencing by Unpaired DNA

该项目的目标是确定在减数分裂过程中未配对DNA如何沉默的潜在机制，减数分裂是产生配子或孢子的过程。 在细胞周期的这一部分中，未配对基因的存在通常表明存在外源DNA元件。 因此，细胞通常通过沉默（关闭）这些基因的表达而受益。 这种途径被称为“未配对DNA减数分裂沉默（MSUD）”，是一种独特的基于RNA的基因沉默系统，首次在橙子面包霉菌粗糙脉孢菌中描述。 但是，由于缺乏配对伴侣的DNA片段也是蠕虫，小鼠和人类沉默的目标，因此MSUD的研究将揭示染色体配对如何影响高等生物的基因调控。 为了扩大代表性不足群体的参与，本项目的调查人员将从他们自己的大学以及非博士生中招募和培训本科生。资助机构和少数群体服务机构。 该项目的研究活动将用于为各种推广方案制定课程计划。 还将努力促进跨学科伙伴关系和STEM（科学、技术、工程和数学）教育。在各种生物体中，基因组监视系统被维持以控制重复元件的表达并限制其传播。 其中一种机制是MSUD，它检查减数分裂前期I期间任何DNA片段与其同源配偶体的配对。 与相似序列不配对的基因产生沉默信号（小RNA种类），随后关闭来自该未配对DNA以及基因组中任何其他（配对或未配对）拷贝的表达。 MSUD利用常见的RNA干扰（RNAi）因子（例如，Argonaute）以靶向特定的mRNA转录物。 使用他们开发的工具（例如，蛋白质相互作用测定、突变株、RNA谱和细胞标记）和各种互补方法（例如，生物化学、细胞学、遗传学和分子生物学），研究人员计划表征MSUD缺陷的脉孢菌突变体，并检查来自MSUD活性的各个位点的蛋白质如何有助于沉默途径。

The goal of this project is to determine the underlying mechanism for how an unpaired DNA is silenced during meiosis, a process that produces gametes or spores. The presence of unpaired genes during this part of the cell cycle is often indicative of a foreign DNA element. Accordingly, the cell usually benefits by silencing (turning off) the expression of these genes. This pathway is called 'Meiotic Silencing by Unpaired DNA (MSUD)' and is a unique RNA-based gene silencing system first described in the orange bread mold, Neurospora crassa. But since DNA segments lacking a pairing partner are also targeted for silencing in worms, mice, and humans, the study of MSUD will shed light on how chromosome pairing affects gene regulation in higher organisms as well. To broaden the participation of underrepresented groups, the investigators of this project will recruit and train undergraduate students from their own university as well as from non-Ph.D.-granting and minority-serving institutions. Research activities from this project will be used to develop lesson plans for various outreach programs. Efforts will also be made to promote interdisciplinary partnerships and STEM (science, technology, engineering, and mathematics) education. In various organisms, genome surveillance systems are maintained to control the expression of repetitive elements and limit their spreading. One of these mechanisms is MSUD, which examines the pairing of any DNA segment with its homologous partner during meiotic prophase I. A gene not paired with a similar sequence generates a silencing signal (a small RNA species), which subsequently turns off the expression from this unpaired DNA as well as from any other (paired or unpaired) copies in the genome. MSUD utilizes common RNA interference (RNAi) factors (e.g., Argonaute) to target specific mRNA transcripts. Using the tools they have developed (e.g., protein interaction assays, mutant strains, RNA profiles, and cellular markers) and various complementary approaches (e.g., biochemistry, cytology, genetics, and molecular biology), the investigators plan to characterize Neurospora mutants defective in MSUD and examine how proteins from various sites of MSUD activity contribute to the silencing pathway.