MECHANISM OF MEIOTIC PAIRING IN DROSOPHILA MALES

雄性果蝇减数分裂配对机制

• 批准号: 6560235
• 负责人: Bruce D. McKEE
• 金额: $ 7.85万
• 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 2002-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6560235
• 关键词: DNA binding protein; DNA directed RNA polymerase; DNA topoisomerases; Drosophilidae; chromosome movement; cytogenetics; fungal genetics; genetic mapping; genetic promoter element; genetic transcription; histones; male; meiosis; nucleic acid repetitive sequence; oligonucleotides; radionuclides; sex chromosomes; site directed mutagenesis; tissue /cell culture; transfection; yeasts

The major goals of this study are to identify meiotic sites in Drosophila and to use them to gain insight into the mechanisms of meiotic pairing. We have utilized cytogenetic methods to show that pairing capacity is widely distributed throughout the euchromatin of chromosome 2, a major autosome, but that a strong pairing site maps to the base of chromosome arm 2L in the same region occupied by the repeated structural genes of the histone. We have also shown that X-Y pairing is mediated by 240bp intergenic spacer repeats from the rDNA loci on the X and Y. X chromosomal insertions of these repeats can restore pairing capacity to X chromosomes deleted for the native pairing region in the heterochromatin. By contrast, fragments of the rDNA transcription unit without promoters or spacers have no pairing ability. Each of the spacer repeats has a functional copy of the pre-rRNA promoter and we have shown by in vitro mutagenesis and functional testing that disabling the "spacer promoters" in arrays of these repeats also prevents them from stimulating X-Y pairing. We propose that pairing sites in Drosophila consist of transcribed sequences or the promoters thereof. The proposed experiments involve development of a novel mini- chromosome assay that can be used to test any candidate sequence for pairing capacity. It will be used to test transgenic insertions of histone repeats and a variety of other candidate sequences, including arrays of promoter sequences from both Drosophila and yeast. The idea that transcription is required for pairing will be tested by attempting to "activated" sequences that lack autonomous pairing capacity by transcription from heterologous promoters. The possibility that pairing involves formation of joint molecules will be investigated by assessing sensitivity of pairing to mismatches between potential partners, with special attention to whether mismatches upstream or downstream of the initiation site are especially disruptive. This latter test is aimed at discovering evidence for or against direct involvement of nascent transcripts in the pairing process. We will also search for sites outside the promoter region of the 240bp spacer repeats that are essential for pairing function of the repeats.

这项研究的主要目标是识别果蝇中的减数分裂地点 并利用它们深入了解减数分裂配对的机制。我们 是否利用细胞遗传学方法表明配对能力广泛 分布在整个染色体2的整体素中，这是一个主要的自种体， 但是，在染色体ARM 2L的底部的强大配对位点图中 组蛋白的重复结构基因所占据的相同区域。 我们还表明，X-Y配对是由240bp的基因间间隔者介导的 X和Y的rDNA基因座的重复。x的X染色体插入 这些重复可以将配对能力恢复为已删除的X染色体 异染色质中的天然配对区域。相比之下，碎片 没有启动子或垫片的rDNA转录单元没有 配对能力。每个垫片重复序列都有一个功能副本 rRNA前启动子，我们已经通过体外诱变和功能显示 测试这些重复序列中禁用“间隔启动子”的测试 还可以防止它们刺激X-y配对。我们建议配对 果蝇中的位点由转录序列或启动子组成 它。提出的实验涉及开发新型微型 可用于测试任何候选序列的染色体测定 配对能力。它将用于测试组蛋白的转基因插入 重复和各种其他候选序列，包括 果蝇和酵母的启动子序列。这个想法 配对需要进行转录，将通过尝试测试 “激活”序列缺乏自主配对能力的序列 来自异源启动子的转录。配对的可能性 涉及组合分子的形成将通过评估来研究 对潜在伴侣之间的配对对不匹配的敏感性， 特别注意上游或下游的不匹配 启动站点特别破坏。后一个测试的目的是 发现或反对直接参与新生的证据 配对过程中的成绩单。我们还将在外面搜索网站 240bp间隔重复序列的启动子区域至关重要 重复的配对函数。