Qri2/Nse4, a component of the essential Smc5/6 DNA repair complex

Bin Hu, Chunyan Liao, Stefan H. Millson, Mehdi Mollapour, Chrisostomos Prodromou, Laurence H. Pearl, Peter W. Piper, Barry Panaretou* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Saccharomyces cerevisiae. We generated temperature-sensitive (ts) mutants in QRI2 and characterized their properties. The mutants arrest after S phase and prior to mitosis. Furthermore, the arrest is dependant on the Rad24 checkpoint, and is also accompanied by phosphorylation of the Rad53 checkpoint effector kinase. The mutants also display genome instability and are sensitive to agents that damage DNA. Two-hybrid screens reveal a physical interaction between Qri2 and proteins that are non-Smc elements of the Smc5/6 DNA repair complex, which is why we propose the name NSE4 for the open reading frame previously known as QRI2. A key role for Nse4 in Smc5/6 function is likely, as overexpressing known subunits of the Smc5/6 complex suppresses nse4(ts) cell cycle arrest. The nse4(ts) growth arrest is non-lethal and unlike the catastrophic nuclear fragmentation phenotype of smc6(ts) mutants, the nucleus remains intact; replicative intermediates and sheared DNA are not detected. This could imply a role for Nse4 in maintenance of higher order chromosome structure.
Original languageEnglish
Pages (from-to)1735-1750
Number of pages15
JournalMolecular Microbiology
Issue number6
Publication statusPublished - 12 Mar 2005
Externally publishedYes


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