Rtf1-Mediated Eukaryotic Site-Specific Replication Termination

摘要

High-fidelity chromosome segregation requires that the sister chromatids produced during S phase alsonbecome paired during S phase. Ctf7p (Eco1p) is required to establish sister chromatid pairing specificallynduring DNA replication. However, Ctf7p also becomes active during G2/M in response to DNA damage.nCtf7p is a phosphoprotein and an in vitro target of Cdc28p cyclin-dependent kinase (CDK), suggesting onenpossible mechanism for regulating the essential function of Ctf7p. Here, we report a novel synthetic lethalninteraction between ctf7 and cdc28. However, neither elevated CDC28 levels nor CDC28 Cak1p-bypass allelesnrescue ctf7 cell phenotypes. Moreover, cells expressing Ctf7p mutated at all full- and partial-consensus CDKphosphorylationnsites exhibit robust cell growth. These and other results reveal that Ctf7p regulation is morencomplicated than previously envisioned and suggest that CDK acts in sister chromatid cohesion parallel tonCtf7p reactions.