The Interaction Between Telomerase and the Chromosome

Michael JarstferProposal：0446019端粒酶是一种重要的核酸聚合酶，它使用其完整的核糖核酸亚基的一部分作为模板来合成位于线性真核细胞染色体两端的DNA3‘链。端粒酶活性的产物是重复的富含G的DNA的单链，它是被称为端粒的特殊核蛋白复合体的一部分。端粒的功能是通过防止正常DNA修复机制对染色体末端的降解和不良识别来发挥作用。当端粒酶活性被抑制时，端粒DNA不会保持，每个完整的细胞周期都会导致端粒变短。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，这个项目将使用多方面的方法来研究端粒酶和染色体之间相互作用的显著特征。这个项目的第一个目标是检查端粒酶和合成染色体模型之间的相互作用。电子显微镜、酶动力学和DNA足迹等技术将用于确定端粒酶-端粒相互作用的全球特征。第二个目标是研究端粒酶和一种称为G-四链体的特殊DNA结构之间的相互作用。由于端粒的富含G的DNA可以折叠成G-四链结构，因此有必要研究G-四链-端粒酶的相互作用，以充分理解染色体末端端粒酶的行为。最终的目标是在单个核苷酸水平上表征端粒酶模板和端粒DNA引物之间的特定相互作用。端粒酶模板位于其RNA亚基的中间。完成这一目标将为端粒酶反应周期中的引物比对和延伸提供一个工作模型。该项目的成功完成将使人们对端粒酶和端粒之间的相互作用有一个全面的了解，并使人们能够更全面地比较端粒酶和其他核酸聚合酶的催化能力。该项目还包括在实验室培训本科生和研究生，以及参加一个针对少数族裔本科生的暑期项目。

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.