Genetic and Molecular Dissection of Meiotic Silencing by Unpaired DNA

不配对 DNA 减数分裂沉默的遗传和分子解析

• 批准号: 0544237
• 负责人: Patrick Shiu
• 金额: $ 52.64万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0544237&HistoricalAwards=false
• 关键词: Genetic; Molecular; Dissection; Meiotic; Silencing

The overall goal of this project is to delineate the mechanism of Meiotic Silencing by Unpaired DNA (MSUD), a novel gene silencing system in Neurospora crassa. MSUD operates during the brief period of diploidy and the subsequent meiotic divisions in the sexual phase of the life cycle. The diploid cell examines the entire genome and compares the pairing of any DNA segment with its homologue during the homologous pairing stage. Any gene-sized or larger segments of DNA not paired with a homologous sequence generates a sequence-specific signal, which subsequently silences the expression of this unpaired DNA, as well as any sequences homologous to it, whether they are paired or not. Since an RNA-directed RNA polymerase (and presumably a double-stranded RNA species) is required for this process, MSUD is likely to depend on the specific destruction of mRNA transcripts, a mechanism shared by RNA interference (RNAi) and other post-transcriptional gene silencing systems. Owing to its ability to compare the genomes of two mating partners, MSUD represents a defense system for the maintenance of genome integrity as well as a possible isolation mechanism for speciation. N. crassa is an excellent model organism to assess the process of meiotic silencing because of its superior genetics and mutant selection, the ease of molecular techniques, and the availability of full genome sequence information. Genetics, cell biology, and other approaches will be used to identify the machinery and the mechanistic steps required for the meiotic silencing system. The study of MSUD in N. crassa will provide an excellent model for the delineation of the mechanism targeting unpaired DNA for silencing during meiosis, a process that could be important for imprinted X-chromosome inactivation and numerous other phenomena. Since RNAi has tremendous potential as an experimental tool to reveal gene functions, the understanding of MSUD and other RNA-based silencing systems could have a broad impact on research in all areas of biology. Furthermore, the P.I. is involved in a number of teaching and mentoring activities and is registered as a mentor for the Ronald McNair Scholars Program, which aims to promote graduate enrollment for underprivileged first-generation college students and members of underrepresented groups.

摘要本项目旨在研究一种新的基因沉默系统MSUD （Meiotic Silencing by Unpaired DNA）的机制。MSUD在二倍体的短暂时期和随后的减数分裂生命周期的有性阶段起作用。二倍体细胞检查整个基因组，并在同源配对阶段比较任何DNA片段与其同源物的配对。任何未与同源序列配对的基因大小或更大的DNA片段都会产生序列特异性信号，该信号随后使该未配对的DNA及其任何同源序列的表达沉默，无论它们是否配对。由于这一过程需要RNA导向的RNA聚合酶（可能是双链RNA），因此MSUD可能依赖于mRNA转录物的特异性破坏，这是RNA干扰（RNAi）和其他转录后基因沉默系统共有的机制。由于能够比较两个交配伴侣的基因组，MSUD代表了维持基因组完整性的防御系统以及物种形成的可能隔离机制。由于其优越的遗传和突变体选择能力、分子技术的易用性以及全基因组序列信息的可获得性，黑草是评估减数分裂沉默过程的良好模式生物。遗传学、细胞生物学和其他方法将用于确定减数分裂沉默系统所需的机制和机制步骤。该研究将为描述在减数分裂过程中靶向未配对DNA沉默的机制提供一个很好的模型，这一过程可能对印迹x染色体失活和许多其他现象很重要。由于RNAi作为揭示基因功能的实验工具具有巨大的潜力，因此对MSUD和其他基于rna的沉默系统的理解可能对生物学所有领域的研究产生广泛的影响。此外，P.I.参与了许多教学和指导活动，并注册为罗纳德·麦克奈尔学者计划的导师，该计划旨在促进贫困的第一代大学生和弱势群体成员的研究生入学。