The Interaction Between Telomerase and the Chromosome

端粒酶是一种重要的核酸聚合酶，它使用其完整RNA亚基的一部分作为模板来合成线性真核生物染色体两端的3'链DNA。端粒酶活性的产物是一条重复的富含g的DNA单链，它是称为端粒的特殊核蛋白复合体的一部分。端粒的功能是防止正常DNA修复机制对染色体末端的降解和错误识别。当端粒酶活性被抑制时，端粒DNA无法维持，每个完整的细胞周期都会导致端粒越来越短。这种端粒侵蚀被认为是决定细胞增殖程度的生物钟。如果细胞在没有端粒维持的情况下继续分裂，遗传不稳定和细胞死亡就会随之而来。端粒在调节细胞增殖中的作用表明，了解端粒酶的机制将具有广泛的意义。为了进一步了解端粒酶，本项目将采用多方面的方法研究端粒酶和染色体之间相互作用的显著特征。本项目的第一个目的是研究端粒酶与合成染色体模型之间的相互作用。包括电子显微镜、酶动力学和DNA足迹在内的技术将用于确定端粒酶-端粒相互作用的全局特征。第二个目标是检查端粒酶和一种叫做g -四重体的特殊DNA结构之间的相互作用。由于端粒富含g的DNA可以折叠成g -四重体结构，因此有必要对g -四重体与端粒酶的相互作用进行表征，以充分理解端粒酶在染色体末端的行为。最后的目标是在单个核苷酸水平上描述端粒酶模板（包含在其RNA亚基中间）和端粒DNA引物之间的特定相互作用。完成这一目标将为端粒酶反应周期中的引物排列和延伸提供一个工作模型。该项目的成功完成将对端粒酶与端粒之间的相互作用提供一个全面的认识，并允许端粒酶与其他核酸聚合酶的催化能力进行更完整的比较。该项目还包括在实验室培训本科生和研究生，以及参加少数族裔本科生暑期项目。

Michael JarstferProposal: 0446019 Telomerase is a remarkable nucleic acid polymerase that uses a portion of its integral RNA subunit as a template for the synthesis of the 3' strand of DNA found at both ends of linear eukaryote chromosomes. The product of telomerase activity is a single strand of repetitive G-rich DNA that is part of a specialized nucleoprotein complex called the telomere. The telomere functions by preventing degradation and untoward recognition of the chromosome ends by the normal DNA repair machinery. When telomerase activity is suppressed, telomeric DNA is not maintained and each complete cell cycle results in increasingly shorter telomeres. This telomere erosion is thought to function as a biological clock that determines the extent of cellular proliferation. If cells continue to divide in the absence of telomere maintenance, genetic instability and cell death ensues. The role of telomeres in regulating cellular proliferation suggests that understanding the mechanism of telomerase will have broad implications. To further the understanding of telomerase, this project will examine the salient features of the interactions between telomerase and the chromosome using a multifaceted approach. The first objective of this project is to examine the interaction between telomerase and synthetic chromosome models. Techniques including electron microscopy, enzyme kinetics, and DNA footprinting will be used to determine the global features of the telomerase-telomere interaction. The second objective is to examine the interaction between telomerase and a specialized structure of DNA called a G-quadruplex. Because the G-rich DNA of the telomere can fold into G-quadruplex structures, it is necessary to characterize the G-quadruplex-telomerase interaction to fully comprehend the behavior of telomerase at the chromosome end. The final objective is to characterize specific interactions at the individual nucleotide level between the template of telomerase, which is contained in the middle of its RNA subunit, and the telomeric DNA primer. Completing this objective will provide a working model for primer alignment and extension during the telomerase reaction cycle. The successful completion of this project will provide a comprehensive view of the interaction between telomerase and the telomere and allow a more complete comparison between the catalytic capabilities of telomerase and other nucleic acid polymerases. The project also involves the training of undergraduate and graduate students in the laboratory, as well as participation in a summer program for undergraduate minorities.