Functional sirtuin enrichment at telomeric repeat clusters. (a) Enrichment of Sir2, Hst1 and Sum1 at terminal TG1-3 repeats at the left telomere of chromosome XV (Tel_ChrXV_L). The black rectangle represents the end of the chromosome and the circle represents the centromere. (b) Enrichment of Sir2, Hst1 and Sum1 at an internal TG1-3 subtelomeric cluster on the right arm of chromosome VIII (Tel_ChrVIII_R). (c) Quantitative ChIP assays measuring the effect of a rap1-17 mutation on telomeric Sir2-myc enrichment (left panel) or Hst1-myc and Sum1-myc enrichment (right panel). The amplified region was either 70 bp or 7,000 bp away from the terminal TG1-3 cluster on the right arm of chromosome VI. The immunoprecipitated PCR signal is relative to the input chromatin PCR signal (Relative ChIP). In this experiment the untagged background signal was subtracted out. Error bars represent standard deviation. (d) Southern blot detection of telomere (TEL) lengths using a probe that hybridizes to poly (TG1-3) sequences. WT, wild type.
Li et al. Genome Biology 2013 14:R48 doi:10.1186/gb-2013-14-5-r48