AN EVOLUTIONARY LINK BETWEEN TELOMERES AND TRANSPOSONS

端粒和转座子之间的进化联系

• 批准号: 6752470
• 负责人: MARY-LOU PARDUE
• 金额: $ 38.69万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-03-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6752470
• 关键词: Drosophilidae; RNA interference; arthropod genetics; biochemical evolution; gene expression; genetic regulation; green fluorescent proteins; heterochromatin; immunoprecipitation; in situ hybridization; molecular cloning; nucleic acid repetitive sequence; polymerase chain reaction; protein structure function; species difference; telomere; tissue /cell culture; transfection; transposon /insertion element; yeast two hybrid system

DESCRIPTION (provided by applicant): Telomere molecular biology is far more complex than originally thought; understanding it is aided by study of evolutionary variants, and Drosophila telomeres are remarkable variants: Drosophila lack telomerase. Instead, Drosophila telomeres are long tandem arrays of two non-LTR retrotransposons, HeT-A and TART, not the arrays of simple repeats generated by telomerase in almost all other organisms. HeT-A and TART are the first transposable elements found with a bona fide role in cell structure; thus, they offer opportunity for better understanding of both telomeres and non-LTR retrotransposons, a major class of retroelements. Having discovered that D.virilis has transposon telomeres, one of our major goals is to use the approximately 60 MY divergence between this species and D. melanogaster to find conserved features in transposon structure and interactions within their host cells by sequence analysis and by cross-species cell biological interaction assays. Another major goal derives from our D. melanogaster studies that provided the first information on the intracellular Iocalizations of Gag proteins from non-LTR retrotransposons and have identified proteins that may be involved in the localization of HeT-A and TARTGags, both at the telomere and in transit. We will use molecular studies to determine the involvement of these proteins with Gag and/or telomere DNA. We wilt also use molecular techniques to study proteins whose telomeric association was detected by genetic analysis. Thus, we now propose (1) to compare the sequences and cell biology of telomere transposons from distantly related species to deepen insight into the evolution of transposon telomeres, (2) to understand the significance of the developmentally regulated transcription of telomere transposons by using RNAi to specifically deplete transcripts and thereby determine which cell types show phenotypic effects and then to study those effects, (3) to analyze the cell biology of retrotransposon targeting to telomeres, using genetic and biochemical techniques to determine the molecular interactions of proteins involved in determining the path of the retrotransposon from the cytoplasm to its target at the end of the chromosome, and (4) to compare the chromatin formed by telomeric transposon arrays with that found in other telomeres.

描述（由申请人提供）：端粒分子生物学远比最初想象的复杂;通过研究进化变体来帮助理解它，果蝇端粒是显着的变体：果蝇缺乏端粒酶。相反，果蝇端粒是两个非LTR反转录转座子HeT-A和TART的长串联阵列，而不是几乎所有其他生物中端粒酶产生的简单重复序列。HeT-A和TART是发现的第一个在细胞结构中具有真正作用的转座因子;因此，它们为更好地理解端粒和非LTR反转录转座子（一种主要的反转录因子）提供了机会。 在发现D.virilis具有转座子端粒之后，我们的主要目标之一是利用该物种与D.通过序列分析和跨物种细胞生物学相互作用测定法，另一个主要目标来自我们的D。黑腹果蝇的研究提供了关于来自非LTR反转录转座子的Gag蛋白的细胞内定位的第一个信息，并且已经鉴定了可能参与HeT-A和TARTGag在端粒和转运中的定位的蛋白。我们将使用分子研究来确定这些蛋白质与Gag和/或端粒DNA的参与。我们也将使用分子技术来研究蛋白质的端粒协会检测的遗传分析。 因此，我们现在提出（1）比较来自远亲物种的端粒转座子的序列和细胞生物学，以加深对转座子端粒进化的理解，（2）通过使用RNAi特异性地消耗转录物来理解端粒转座子的发育调节转录的意义，从而确定哪些细胞类型表现出表型效应，然后研究这些效应，（3）分析逆转录转座子靶向端粒的细胞生物学，使用遗传和生物化学技术来确定参与确定逆转录转座子从细胞质到其在染色体末端的靶标的路径的蛋白质的分子相互作用，以及（4）比较端粒转座子阵列形成的染色质与在其他端粒中发现的染色质。