Telomeric Capping Complex of Drosophila Chromosomes

果蝇染色体的端粒加帽复合物

基本信息

批准号：
6605038
负责人：
HARALD BIESSMANN
金额：
$ 4.01万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-08-01 至 2004-12-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant) This research will be done primarily in Russia as an extension of NIH Grant D/GM-56729-02. The DNA structure of Drosophila melanogaster telomeres has been worked out in sufficient detail, but very little is known about its chromatin structure and the telomere binding proteins. We propose that there are two distinct protein complexes located at Drosophila telomeres: an end-binding complex required for "capping," and another protein complex associated with the subtelomeric repetitive (TAS) region, which is involved in gene silencing. While the parent grant R0l GM56729 (05/01/1998-04/30/03) studies the latter, this FIRCA supplement will focus on the characterization of the end-binding complex, which is located at the termini of Drosophila chromosomes to prevent telomeric fusions and protect the end from being recognized as double strand DNA break by cell cycle checkpoints. No components of this complex have yet been identified, but our preliminary work has, for the first time, provided genetic evidence for the existence of such a terminal capping structure. This newly discovered terminal deficiency effect (called TDE) will be used to characterize protein components of the end-binding complex. To this end, we will investigate if the chromatin structure of a DNA region is altered when it is located at the end of a terminally deleted chromosome. This will provide a "footprint" of the terminal capping complex, and determine the size of the affected region. Effects of TDE modifiers on the terminal chromatin structure will also be studied. Molecular and genetic approaches will be used to investigate a possible role of two candidate proteins (HP1 and Ku) in TDE, and genetic screens will be performed to identify genes and their protein products that may participate in the formation of the telomeric protein complex. Results from these experiments will complement and extend studies supported in the parent grant and greatly increase our understanding of the complex nucleo-protein structure at the chromosome ends.

描述（由申请人提供）作为 NIH 拨款的延伸，这项研究将主要在俄罗斯进行 D/GM-56729-02。果蝇端粒的 DNA 结构已在足够的细节，但对其染色质结构和了解知之甚少端粒结合蛋白。我们认为有两种不同的蛋白质位于果蝇端粒的复合物：末端结合复合物 “加帽”和另一种与亚端粒相关的蛋白质复合物重复（TAS）区域，参与基因沉默。当家长 grant R0l GM56729 (05/01/1998-04/30/03) 研究后者，这个 FIRCA 补充材料将重点关注末端结合复合物的表征，该复合物位于果蝇染色体末端，可阻止端粒融合并保护末端不被识别为双链 DNA 断裂细胞周期检查点。该复合体的任何成分尚未被识别，但我们的前期工作首次提供了基因证据这种末端封盖结构的存在。这个新发现的末端缺陷效应（称为 TDE）将用于表征蛋白质末端结合复合物的组成部分。为此，我们将调查是否当DNA区域位于末端时，染色质结构会发生改变末端删除的染色体。这将提供一个“足迹” 末端封端复合物，并确定受影响区域的大小。 TDE 修饰剂对末端染色质结构的影响也将是研究过。将使用分子和遗传学方法来研究两种候选蛋白（HP1 和 Ku）在 TDE 中的可能作用，以及遗传将进行筛选以识别可能的基因及其蛋白质产物参与端粒蛋白复合物的形成。结果来自这些实验将补充和扩展家长支持的研究授予并大大增加我们对复杂核蛋白的理解染色体末端的结构。