title: Rif1 and rif2 inhibit localization of tel1 to DNA ends.
abstract: Chromosome ends, known as telomeres, have to be distinguished from DNA double-strand breaks (DSBs) that activate the DNA-damage checkpoint. In budding yeast, the ATM homolog Tel1 associates preferentially with short telomeres and promotes telomere addition. Here, we show that the telomeric proteins Rif1 and Rif2 attenuate Tel1 recruitment to DNA ends through distinct mechanisms. Both Rif1 and Rif2 inhibit the localization of Tel1, but not the Mre11-Rad50-Xrs2 (MRX) complex, to adjacent DNA ends. Rif1 function is weaker at short telomeric repeats compared with Rif2 function and is partly dependent on Rif2. Rif2 competes with Tel1 for binding to the C terminus of Xrs2. Once Tel1 is delocalized, MRX does not associate efficiently with Rap1-covered DNA ends. These results reveal a mechanism by which telomeric DNA sequences mask DNA ends from Tel1 recognition for the regulation of telomere length.
authors.affiliation: Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Hirano
authors.forename: Kenzo
authors.initials: K
authors.lastname: Fukunaga
authors.forename: Katsunori
authors.initials: K
authors.lastname: Sugimoto
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000089804:Shelterin Complex; D016615:Telomere / Q000378:metabolism; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C086930:RAD50 protein, S cerevisiae; C440829:RAP1 protein, S cerevisiae; C105362:RIF2 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; C086929:XRS2 protein, S cerevisiae; C074461:RIF1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae