Essential functions of amino-terminal domains in the yeast telomerase catalytic subunit revealed by selection for viable mutants

Amino terminal domains in the yeast telomerase catalytic subunit are discussed with consideration of their essential functions shown by selection for viable mutants. A large library having in it random mutations in the amino terminus of the EST2 gene, the one that encodes the Saccharomyces cerevisiae telomerase reverse transcriptases (TERTs), was set up. Certain functional alleles were selected by ability to rescue senescence of telomerase-negative cells. Analysis was carried out on 265 mutations.