A genome-wide screen for Saccharomyces cerevisiae deletion mutants that affect telomere length

Abstract

Telomeres are nucleoprotein structures present at the ends of eukaryotic chromosomes that play a central role in guarding the integrity of the genome by protecting chromosome ends from degradation and fusion. Length regulation is central to telomere function. To broaden our knowledge about the mechanisms that control telomere length, we have carried out a systematic examination of approximately 4,800 haploid deletion mutants of Saccharomyces cerevisiae for telomere-length alterations. By using this screen, we have identified >150 candidate genes not previously known to affect telomere length. In two-thirds of the identified mutants, short telomeres were observed; whereas in one-third, telomeres were lengthened. The genes identified are very diverse in their functions, but certain categories, including DNA and RNA metabolism, chromatin modification, and vacuolar traffic, are overrepresented. Our results greatly enlarge the number of known genes that affect telomere metabolism and will provide insights into how telomere function is linked to many other cellular processes.

Fig. 1.

Representive Southern blot of mutants that alter S. cerevisiae telomere length. Southern blot of XhoI-digested DNA of single gene knockout mutants of S. cerevisiae probed with telomeric sequence. Gene or ORF names are indicated as are strain BY4741 controls (WT). Samples of DNA from mutants were combined with restriction-digested plasmid DNA to provide internal size standards. The two internal control bands are fragments of the plasmid pYt103 containing telomeric sequences that were generated by mixing separate digests done with BsmAI and with TaqI (producing the 1,835- and 644-bp fragments, respectively). The panel on the left shows a strain BY4741 control (WT p–) as well as the size standards without added yeast DNA.