Rif1 Binding and Control of Chromosome-Internal DNA Replication Origins Is Limited by Telomere Sequestration

Lukas Hafner, Aleksandra Lezaja, Xu Zhang, Laure Lemmens, Maksym Shyian, Benjamin Albert, Cindy Follonier, Jose Manuel Nunes, Massimo Lopes, David Shore, Stefano Mattarocci
2018 Cell Reports  
The Saccharomyces cerevisiae telomere-binding protein Rif1 plays an evolutionarily conserved role in control of DNA replication timing by promoting PP1-dependent dephosphorylation of replication initiation factors. However, ScRif1 binding outside of telomeres has never been detected, and it has thus been unclear whether Rif1 acts directly on the replication origins that it controls. Here, we show that, in unperturbed yeast cells, Rif1 primarily regulates late-replicating origins within 100 kb
more » ... a telomere. Using the chromatin endogenous cleavage ChEC-seq technique, we robustly detect Rif1 at late-replicating origins that we show are targets of its inhibitory action. Interestingly, abrogation of Rif1 telomere association by mutation of its Rap1-binding module increases Rif1 binding and origin inhibition elsewhere in the genome. Our results indicate that Rif1 inhibits replication initiation by interacting directly with origins and suggest that Rap1-dependent sequestration of Rif1 increases its effective concentration near telomeres, while limiting its action at chromosome-internal sites. Graphical Abstract Highlights d Rif1 binds directly to DNA replication origins that it regulates d Sequestration through Rap1 binding promotes Rif1 targeting to telomere-proximal origins d Genome-wide replication dynamics are altered by cell synchronization
doi:10.1016/j.celrep.2018.03.113 pmid:29694906 fatcat:6vwvaprn5reaxpevip7g7nakwe