Files in this Data Supplement:

• Supplemental file 1 - Supplemental Table S1: Plasmids used in this study.
  Supplemental Table S2: Oligonucleotides used in this study.
  Supplementary Figure S1: Negative telomere length regulation by tethered Rif proteins and by PDZ-mediated protein interactions is not dependent of RAD52.
  Supplementary Figure S2: Levels of rap1∆Cp are comparable to wild-type while rap1-17p levels are much reduced.
  Supplementary Figure S3: Levels of Rap1-PDZp and Rap1∆C-PDZp are comparable to wild-type Pap1p levels.
  Supplementary Figure S4: PDZ-mediated protein interactions at the telomere confer length regulation.
  Other supplementary information:
  Strain passaging on plates versus liquid culture and "jumpy" telomers.
  rap1∆C versus rap1-17.
  PAP1-PDX confers telomere length regulation in the absence of the Rif proteins.
  Rap1p fusion proteins that do not lead to shorter telomeres.
  Supplementary references.