STIMULATION OF CHROMOSOME PAIRING AND EXCHANGE BY RDNA

RDNA 刺激染色体配对和交换

• 批准号: 3298080
• 负责人: Bruce D. McKEE
• 金额: $ 9.91万
• 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 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3298080
• 关键词: DNA binding protein; Drosophilidae; alleles; chromosome aberrations; cytogenetics; gene conversion; gene expression; genes; genetic manipulation; genetic mapping; genetic recombination; genetic transcription; immunoelectrophoresis; meiosis; microinjections; molecular cloning; molecular genetics; natural gene amplification; nucleic acid hybridization; nucleic acid probes; nucleic acid sequence; radionuclides; ribosomal DNA; sex chromosomes; transposon /insertion element

The objectives are to analyze the role of rDNA in stimulation of asynoptonemal X:Y pairing and to explore the maintenance of rDNA sequence homogeneity through non-allelic recombination in Drosophila. The experiments are motivated in part by the observation, described in Preliminary Studies, that a cloned transformed rDNA cistron stimulates X:Y pairing when located at a euchromatic site on a pairing deficient X chromosome but not when located on an autosome. Cloned rDNA cistrons transformed into the germ line via P-element vectors will be a) remobilized to obtain new X-linked insertions, and b) destabilized to obtain overlapping internal deletions, using a high efficiency hybrid dysgenesis method. The resulting variants will be mapped and analyzed at the molecular level and used to: 1) assess the relative importance of DNA homology versus gene expression in promotion of X:Y pairing by comparing rDNA sequence requirements for pairing stimulation, transcription, nucleolus formation, and ribosome assembly. 2) test for position and copy number effects on rDNA stimulation of X:Y pairing and rDNA expression. 3) determine the rate and mechanism of rDNA recombination by screening for exchanges and conversions between allelic and non- allelic euchromatic rDNA cistrons. 4) test for magnification (heritable amplification triggered by partial rDNA deficiency) of isolated euchromatic cistrons 5) assess the relative importance of homology versus expression in recombination and magnification by identifying sequence requirements via deletion mapping. In addition, clones of ribosomal insertion sequences will be tested by P-element transformation for effects on X:Y pairing. This research has possible significance for human health. Participation of nucleoli in meiotic chromosome pairing has been linked to non-homologous segregation of nucleolus organizer- containing chromosomes, leading to nondisjunction and Down's syndrome. In addition, non-allelic homologous recombination between dispersed repeated genes is a likely cause of chromosome rearrangements responsible for birth defects and cancer.

目的是分析rDNA在刺激中的作用 异步to x：y配对并探索维护 rDNA序列均匀性通过非平行性重组 果蝇。 实验是由 在初步研究中描述的观察结果是克隆 转化的rDNA Cistron刺激X：y配对。 配对缺陷X染色体上的圣体位点，但没有 当位于加体上时。 克隆的rDNA cistron转换 通过P元素向量进入种系将是a）重新验证 获得新的X连锁插入，b）不稳定以获得 使用高效率混合动力车重叠的内部缺失 失去障碍法。 由此产生的变体将被映射，并且 在分子水平上进行分析，并用于： 1）评估DNA同源性与基因的相对重要性 通过比较rDNA促进X：Y配对的表达 配对刺激，转录的序列要求， 核仁形成和核糖体组装。 2）测试位置和拷贝数对rDNA刺激的影响 x：y配对和rDNA表达。 3）确定rDNA重组的速率和机制 筛查等位基因和非 - 等位基因rDNA cistron。 4）放大测试（可遗传放大由 孤立的圣经cistron的部分rDNA缺乏症） 5）评估同源与表达的相对重要性 通过识别序列的重组和放大 通过删除映射的要求。 此外，将测试核糖体插入序列的克隆 通过p元素转换，以对x：y配对的影响。 这项研究对人类健康具有可能的意义。 核仁在减数分裂染色体配对中的参与已经 与核仁组织者的非同源分离有关 含有染色体，导致非分离和唐 综合征。 另外，非平行同源重组 分散的重复基因之间可能是染色体的原因 负责先天缺陷和癌症的重排。