Exploring the assembly and function of the telomerase accessory proteins Est1 and Est3 in Saccharomyces cerevisiae

Abstract

The work presented in this dissertation focuses on a how the telomerase complex assembles both in vivo and in vitro and begins to explore how one member of the telomerase enzyme in the budding yeast, Saccharomyces cerevisiae, termed Est3p, functions within the complex. I have discovered that Est1 protein levels are lower in G1 phase of the cell cycle due to regulated degradation by the ubiquitin-proteasome system. Additionally, I have elucidated a direct protein-protein interaction between the TEN domain of the Est2 protein and a charged region of the Est3 protein. Finally, I have begun to uncover a potential function of the Est3 protein in stimulating or activating telomerase activity in vitro. This activity appears to be dependent upon stable interaction with the Est2 TEN domain.