Mechanism of Meiotic Pairing in Drosophila

果蝇减数分裂配对机制

• 批准号: 6548541
• 负责人: Bruce D. McKEE
• 金额: $ 22.96万
• 依托单位: UNIVERSITY OF TENNESSEE KNOXVILLE
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6548541
• 关键词: DNA binding protein; DNA directed RNA polymerase; DNA topoisomerases; Drosophilidae; chromosome movement; cytogenetics; fungal genetics; gene mutation; genetic crossing over; genetic mapping; genetic promoter element; genetic transcription; male; meiosis; nucleic acid repetitive sequence; nucleoproteins; phenotype; protein localization; protein protein interaction; regulatory gene; ribosomal RNA; sex chromosomes; sperm; tissue /cell culture; yeast two hybrid system; yeasts

DESCRIPTION (provided by applicant): Meiotic pairing is essential for proper segregation of homologs and production of chromosomally normal gametes. Pairing abnormalities cause homolog nondisjunction, resulting in aneuploidy, a major cause of spontaneous abortion and developmental abnormalities in humans. The proposed experiments utilize Drosophila male meiosis as a model system to explore how homologs align in early meiosis, how they develop cohesive bonds stable enough to resist spindle forces and how those bonds are rapidly broken when homologs segregate at anaphase. The experiments build on the prior identification of a 240bp repeated sequence located in the intergenic spacer of the rRNA genes on the X and Y chromosomes that functions as the primary X-Y meiotic pairing site. In the previous funding period we demonstrated that an RNA polymerase I promoter located in each repeat is essential for meiotic pairing. We also generated a large collection of novel meiotic mutations that define nine genes (pairing failure (pf) 1-9) needed for proper meiotic segregation of all chromosomes. We discovered that one of the genes identified in this screen (pf-1) encodes a novel member of the stromalin family of cohesin proteins (dSA-2) that we postulate to function specifically in homolog pairing. Aim 1 of this proposal is a further exploration of the link between transcription and pairing, examining both the role of rDNA transcripts in X-Y pairing, and the role of transcription generally in pairing. In aim 2 we will further characterize the phenotypes of pf mutations, focusing particularly on the kinetics of pairing failure in. male meiosis, and on possible roles in other pairing pathways in female meiosis and in somatic tissues. Aim 3 will be a comprehensive molecular analysis of the dSA-2 protein, focused especially on testing the hypothesis that it is a meiotic cohesin with a specialized role in homolog pairing. In aim 4, we propose to identify and analyze additional genes involved in male meiotic homolog pairing. Taken together, these experiments are expected to advance our understanding of chromosome pairing in Drosophila and to provide models for pairing mechanisms that can be tested in mammals.

描述（由申请人提供）：减数分裂配对对于正确分离同源物和染色体正常配子的产生至关重要。配对异常会导致同源性非分离，导致非整倍性，这是人类自发流产和发育异常的主要原因。提出的实验利用果蝇男性减数分裂作为模型系统，以探索同源物在早期减数分裂中如何保持一致，它们如何形成足够稳定的凝聚力键以抵抗纺锤力的力以及当同源物分离过后期时如何迅速损坏这些键。该实验建立在X和Y染色体上rRNA基因的基因间间隔物中的240bp重复序列的先前鉴定上，该序列可作为主要的X-Y减数分裂配对位点。在上一个资金期间，我们证明了每个重复中的RNA聚合酶I启动子对于减数分裂配对至关重要。我们还产生了大量新型的减数分裂突变，这些突变定义了所有染色体适当的减数分裂隔离所需的九个基因（配对失败（PF）1-9）。我们发现，在此筛选中鉴定出的一个基因（PF-1）编码了我们假设在同源配对中专门起作用的粘蛋白蛋白（DSA-2）的Stromalin家族的新成员。该提案的目标1是对转录与配对之间的联系的进一步探索，既研究rDNA转录物在X-Y配对中的作用，又研究转录在配对中的作用。在AIM 2中，我们将进一步表征PF突变的表型，特别关注男性减数分裂的配对衰竭的动力学，以及女性减数分裂和体细胞组织中其他配对途径的可能作用。 AIM 3将是对DSA-2蛋白的综合分子分析，尤其集中在测试以下假设：它是一种减数分裂粘着蛋白，在同源配对中具有专门作用。在AIM 4中，我们建议识别和分析与男性减数分裂同源配对有关的其他基因。综上所述，这些实验有望提高我们对果蝇中染色体配对的理解，并为可以在哺乳动物中测试的配对机制提供模型。