Molecular Mechanism of Telomerase Action

端粒酶作用的分子机制

• 批准号: 8849458
• 负责人: Julian J-L Chen
• 金额: $ 28.25万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8849458
• 关键词: Active Sites; Affect; Affinity; Aging; Binding; Biochemical; Biological Assay; Biology; Chromosomes; Comparative Study; DNA; DNA Primers; DNA-Directed DNA Polymerase; Data; Dissociation; Elements; Enzymes; Foundations; Goals; Inosine; Kinetics; Left; Malignant Neoplasms; Measures; Mediating; Modeling; Modification; Molecular; Natural regeneration; Nucleotides; Oligonucleotides; Outcome; Polymerase; Property; RNA; RNA Sequences; RNA-Directed DNA Polymerase; Research; Ribonucleoproteins; Role; Site-Directed Mutagenesis; Specificity; Telomerase; Telomerase RNA Component; Testing; Work; base; innovation; insight; mutant; novel; programs; research study; screening; telomerase reverse transcriptase; telomere; transcriptome sequencing

DESCRIPTION (provided by applicant): Project Summary Telomerase is a specialized reverse transcriptase (RT) that synthesizes telomere DNA repeats at chromosome ends, using only a very short region of its intrinsic telomerase RNA (TR) subunit as template. This highly specialized function of telomerase relies on a special mechanism whereby the template RNA and the telomeric DNA dissociate and realign during the processive synthesis of repeats. However, the detailed mechanism of telomerase template translocation remains to be determined. This research program aims to articulate the unique mechanism of telomerase action and identify elements that regulate specific steps of template translocation. Although telomerase uses the single-stranded telomeric DNA as its native substrate, we have recently discovered that telomerase can act as a conventional RT utilizing RNA/DNA duplex as substrate. More surprisingly, telomerase recognizes the duplex substrate with a sequence-specificity. These crucial findings have provided great insights into the molecular mechanism of telomerase action. We hypothesize that duplex- binding and duplex-dissociation are important steps of the telomere-repeat synthesis cycle, and regulate telomere-repeat addition rate and processivity. Specific Aims of the research program include (1) Determining the role duplex-binding affinity in template translocation efficiency, (2) Determining the rate-limiting step of template translocation, and (3) characterize the sequence- dependent termination of nucleotide addition by telomerase. We expect the outcomes of these experiments will greatly add to our understanding of telomerase mechanism.

描述（由申请人提供）： Project摘要端粒酶是一种专业的逆转录酶（RT），它仅使用其固有的端粒酶RNA（TR）亚基作为模板，合成染色体末端的端粒DNA重复序列。端粒酶的高度专业化功能取决于一种特殊的机制，在该机制中，在重复序列的过程合成过程中，模板RNA和端粒DNA分离和重新对准。但是，端粒酶模板易位的详细机制尚待确定。该研究计划旨在阐明端粒酶作用的独特机制，并确定调节模板转运特定步骤的元素。尽管端粒酶使用单链端粒DNA作为天然底物，但我们最近发现端粒酶可以用RNA/DNA双链体作为底物充当常规RT。更令人惊讶的是，端粒酶以序列特异性识别双链底物。这些关键发现为端粒酶作用的分子机制提供了很好的见解。我们假设双链结合和双链分解是端粒重复合成周期的重要步骤，并调节了端粒重复的加法率和加工率。研究计划的具体目的包括（1）确定模板易位效率中的双相结合亲和力，（2）确定模板易位的速率限制步骤，（3）表征通过端粒酶添加核苷酸的序列终止。我们预计这些实验的结果将极大地增加我们对端粒酶机制的理解。