12 Budding Yeast Telomeres

Abstract

Yeast telomere biology emerged in the early 1980s with a seminal study by Szostak and Blackburn (1982). Combining their respective interests in yeast artificial chromosomes and ciliate telomeres, they constructed a trans-kingdom chromosome: a linear yeast episome with ciliate telomeric DNA on its ends. When introduced into budding yeast, these evolutionarily distant ciliate termini were elongated by the direct addition of yeast telomeric DNA. This lent impetus to the hypothesis that cells contained a telomere-specific enzymatic activity, analogous to terminal transferase, that was capable of extending the ends of chromosomes (see the Appendix). Of more immediate importance to the nascent yeast telomere biology field, however, was the molecular cloning of yeast telomeres, which provided a crucial molecular reagent that could be used to monitor the behavior of yeast chromosome termini (Shampay et al. 1984; Walmsley et al. 1984). This prompted a flurry of studies that probed the dynamic nature of chromosome ends in yeast (Dunn et al. 1984; Horowitz et al. 1984; Pluta et al. 1984) and also initiated the process of identifying the genes required for telomere length regulation (Carson and Hartwell 1985; Lustig and Petes 1986). Over the past 20 years, studies from numerous laboratories have greatly expanded our knowledge of the details of yeast telomere structure, as well as the gene products that maintain yeast chromosome ends. This chapter discusses some of the main insights that have resulted from these studies and highlights several major unanswered questions.

YEAST TELOMERE STRUCTURE
Telomeric DNA: An Irregular repeat Sequence with...