This project will reveal new insights into the evolution of telomerase in plants. Telomerase is an essential enzyme responsible for making protective caps, called telomeres, located at the ends of chromosomes. Telomeres are important because they help preserve chromosomal integrity by preventing chromosomal shortening associated with cellular aging or cancer. Previous studies have revealed that telomerase in plants is quite different than telomerase in ciliates, fungi, and animals, but the reasons for these differences are poorly understood. Focusing on plants as the study system, this research will uncover the processes that control telomerase evolution and thus provide better understanding of how chromosome stability is maintained. The project will provide research training for undergraduates, graduate students, and a local high school biology teacher, and students in the teacher's AP biology classes will benefit from new research-focused curricula developed through participation of their teacher in the research.
Telomerase is an essential eukaryotic ribonucleoprotein responsible for maintaining the length of telomeres, thus ensuring genomic stability. Mounting evidence from ciliates, fungi and animals supports the idea that a core set of structural elements is required for the interaction of the two critical components of telomerase: the telomerase RNA and the telomerase reverse transcriptase protein. A wealth of structural and functional data suggests that telomerase evolved early in the history of eukaryotes and may therefore represent a key innovation precipitating the evolution of linear chromosomes. As a result, telomerase is expected to be under strong purifying selection to preserve function. However, while the reverse transcriptase is well conserved among eukaryotes, the evolutionary history of telomerase RNA is more complex. For example, the pace of telomerase RNA evolution in plants is dramatically different than it is in ciliates, fungi and animals. Thus, plants provide an unprecedented window into the processes that drive telomerase RNA evolution. Using a biochemical and comparative genomic approaches, plant telomerase RNAs will be studied to learn how changes in these molecules affect genome stability in eukaryotes. This will provide a deeper understanding of how long non-coding RNAs like telomerase RNA contribute to the origin and maintenance of genome complexity in eukaryotes.
