NHEJ regulation by mating type is exercised through a novel protein, Lif2p, essential to the Ligase IV pathway
Abstract
In the yeast Saccharomyces cerevisiae, DNA double strand break (DSB) repair by nonhomologous end-joining (NHEJ) requires the DNA end-binding heterodimer Yku70p–Yku80p and the ligase Dnl4p associated with its cofactor Lif1p. NHEJ efficiency is down-regulated inMATa/MATα cells relative to MATa or MATαcells, but the mechanism of this mating type regulation is unknown. Here we report the identification of Lif2p, a S. cerevisiaeprotein that interacts with Lif1p in a two-hybrid system. Disruption ofLIF2 abolishes the capacity of cells to repair DSBs by end-joining to the same extent than lif1 and dnl4mutants. In MATa/MATα cells, Lif2p steady-state level is strongly repressed when other factors involved in NHEJ are unaffected. Increasing the dosage of the Lif2p protein can suppress the NHEJ defect in a/α cells. Together, these results indicate that NHEJ regulation by mating type is achieved, at least in part, by a regulation of Lif2p activity.
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Footnotes
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↵1 Corresponding author.
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E-MAIL marcand{at}jonas.saclay.cea.fr; FAX 33-1-69-08-47-12.
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Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.206801.
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- Received April 30, 2001.
- Accepted September 26, 2001.
- Cold Spring Harbor Laboratory Press