CAREER: Molecular Evolution of Telomerase Ribonucleoprotein: A Phylogenetic Study of Telomerase RNA Structure and Function

Arizona State University, Scottsdale AZ

Investigators

Abstract

Telomerase is a unique ribonucleoprotein (RNP) that varies dramatically among ciliates, yeasts and vertebrates in its biochemical composition and biogenesis pathway. In different species, telomerase RNA associates with different proteins and shares distinct biogenesis pathways with other RNP enzymes. The molecular mechanism underlying the unusual course of telomerase RNP evolution remains unclear. To better understand the diverse mechanisms of telomerase biogenesis and regulation, it is essential to identify and characterize telomerase RNA and its associated proteins from all major representatives of eukaryotes. One of the most difficult challenges in studying the telomerase RNP is identifying telomerase RNA homologues, mainly due to the lack of sequence similarity between groups of species. The goal of this research project is to identify telomerase RNA genes from invertebrates, plants, algae and some early-branching protozoa for comparative studies. To achieve this challenging goal, a novel strategy is designed to clone unknown telomerase RNA genes. In spite of its unusual sequence and size variation, telomerase RNA forms a stable complex with telomerase reverse transcriptase (TERT) protein in vitro. Taking advantage of this specific RNA-protein interaction, recombinant TERT proteins will be used as bait to affinity-purify their telomerase RNA counterparts using a modified in vitro selection scheme. The identification of telomerase RNAs from different branches of eukaryotes will be followed by structural and functional characterization of the reconstituted RNP. Collectively, the results from this project will provide new insights into the molecular evolution of telomerase structure and function. Telomerase ribonucleoprotein is a unique RNA-protein enzyme that maintains genomic stability in eukaryotic cells. The telomerase RNA unusually adopts various species-specific structural domains and interacts with various protein components in different groups of species. This project aims to determine the structure of telomerase RNAs from all major groups of eukaryotic species and to understand the structure-function relationship of these RNAs. Insights gained from this work will not only offer a comprehensive picture of the molecular evolution of telomerase enzyme, but also provide fundamental knowledge applicable to the studies of other ribonucleoprotein enzymes. This research project also involves training and mentoring students at the high school, undergraduate and graduate levels. The hands-on experience in conducting real research projects will help motivate and encourage students to pursue research careers in science.