Understanding the Physical Mechanism of Telomere End Capping

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Proper capping of telomeres is critical for maintaining chromosomal integrity by preventing degradation, recombination, end-to-end fusions and recognition by DNA damage checkpoints. The absence of telomere capping leads to catastrophic chromosomal damage. While the proteins that participate in these functions in vivo have been identified, scant information on their function in vitro is available. Biochemical and structural data are needed to develop viable mechanistic models for telomere function. The objective of this research program is to obtain detailed biochemical and structural data to determine the mechanism of telomere capping. The proteins comprising the S. cerevisiae chromosomal end cap have been genetically defined as Cdc13, Stn1 and Ten1. The principal investigator will determine the physical basis for capping activity mediated by these proteins. Protein/protein and protein/nucleic acid interactions will be measured to develop a complete biochemical understanding of the telomere end-protection complex. NMR will be used to map intermolecular interfaces of the end-capping complexes. Insights into the mechanism of end protection will be obtained by mutagenesis of these interfaces in vitro and in vivo. Furthermore, the investigator will study telomerase activity in the presence and absence of capping components. This hypothesis-driven research program will, through a series of focused and prioritized objectives, provide significant biochemical and structural insights into the mechanism of capping complex formation. Completion of this program will lead to important mechanistic understanding of telomere maintenance, an essential process in eukaryotic cells. The program will also make extensive use of multi-institutional high-field NMR facilities, providing both an excellent training opportunity for program participants as well as supporting the scientific infrastructure. In addition, the program will increase training opportunities for groups under-represented in science. The PI will continue mentoring activities for students, postdoctoral fellows and young faculty from under-represented groups, and will target undergraduate institutions with minority populations for outreach.