Telomerase function and regulation in a new model system

新模型系统中的端粒酶功能和调节

• 批准号: 7094239
• 负责人: NEAL F LUE
• 金额: $ 29.2万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7094239
• 关键词: Candida albicans; enzyme activity; enzyme mechanism; fungal genetics; genetic recombination; immunoprecipitation; intermolecular interaction; mutant; protein protein interaction; protein purification; protein structure function; site directed mutagenesis; telomerase; telomere

DESCRIPTION (provided by applicant): Telomerase is a ribonucleoprotein complex responsible for extending the dG-rich strand of the telomere terminal repeats. It employs a small segment of a stably associated RNA component as template, and pre-existing chromosomal ends as primers to accomplish reverse transcription. Telomerase activity isspecifically activated in cancer cells, and promotes neoplastic transformation by endowing cells with unlimited replicative potential. Selective inactivation of telomerase in tumor cells leads to telomere shortening and apoptosis, validating the potential of telomerase inhibitors in anti-cancer therapy. The goal of this research is to investigate telomerase regulation and function in Candida albicans, a relatively unexplored experimental system. In contrast to other well-studied fungi, Candida possesses longer telomere tracts, a regular extended telomere repeat, and exhibits more active recombination at telomeres. Because of these unusual features, we have been able to develop unique biochemical and molecular toolsfor addressing fundamental issues in the field. Most importantly, we have been able to demonstrate for the first time the effects of two regulatory factors on telomerase activity in vitro, and are thus in a position to approach telomerase regulation using the powerful combination of yeast genetics and biochemistry. Our preliminary studies suggest two major hypotheses: (1) the CaEstlp and CaEst3p subunit of the telomerase complex can activate telomerase function through protein-protein and/or protein-DNA interaction, and (2) some telomerase subunits can participate in the protection of telemere ends independent of their telomere extension function. To examine these hypotheses, we will utilize a series of biochemical, genetic, and cell biological assays to analyze Candida telomeres and telomerase inappropriate mutant strains. We will also develop purified in vitro systems to assess telomerase activation by regulatory factors, and to investigate relevant protein-DNA and protein-protein interactions. We anticipate that our findings will contribute to a detailed molecular understanding of telomerase function and regulation.

描述（由申请人提供）：端粒酶是一种核糖核蛋白复合物，负责延伸端粒末端重复序列的富含 dG 的链。它采用一小段稳定相关的RNA成分作为模板，并以预先存在的染色体末端作为引物来完成逆转录。端粒酶活性在癌细胞中被特异性激活，并通过赋予细胞无限的复制潜力来促进肿瘤转化。肿瘤细胞中端粒酶的选择性失活导致端粒缩短和细胞凋亡，验证了端粒酶抑制剂在抗癌治疗中的潜力。 本研究的目的是研究白色念珠菌（一个相对未经探索的实验系统）中端粒酶的调节和功能。与其他经过充分研究的真菌相比，念珠菌拥有更长的端粒束、有规律的延长端粒重复序列，并且在端粒处表现出更活跃的重组。由于这些不寻常的特征，我们已经能够开发独特的生化和分子工具来解决该领域的基本问题。最重要的是，我们首次能够在体外证明两种调控因子对端粒酶活性的影响，因此能够利用酵母遗传学和生物化学的强大组合来实现端粒酶调控。我们的初步研究提出了两个主要假设：（1）端粒酶复合物的CaEstlp和CaEst3p亚基可以通过蛋白质-蛋白质和/或蛋白质-DNA相互作用激活端粒酶功能，（2）一些端粒酶亚基可以参与端粒的保护末端独立于其端粒延伸功能。为了检验这些假设，我们将利用一系列生化、遗传和细胞生物学测定来分析念珠菌端粒和端粒酶不适当的突变株。我们还将开发纯化的体外系统来评估调节因素对端粒酶的激活，并研究相关的蛋白质-DNA 和蛋白质-蛋白质相互作用。我们预计我们的发现将有助于对端粒酶功能和调节的详细分子理解。