» Articles » PMID: 39174552

Sae2 Controls Mre11 Endo- and Exonuclease Activities by Different Mechanisms

Overview
Journal Nat Commun
Specialty Biology
Date 2024 Aug 22
PMID 39174552
Authors
Affiliations
Soon will be listed here.
Abstract

DNA double-strand breaks (DSBs) must be repaired to ensure cell survival and genomic integrity. In yeast, the Mre11-Rad50-Xrs2 complex (MRX) collaborates with Sae2 to initiate DSB repair. Sae2 stimulates two MRX nuclease activities, endonuclease and 3'-5' exonuclease. However, how Sae2 controls the two nuclease activities remains enigmatic. Using a combined genetic and biochemical approach, we identified a separation-of-function rad50 mutation, rad50-C47, that causes a defect in Sae2-dependent MRX 3'-5' exonuclease activity, but not endonuclease activity. We found that both the endo- and 3'-5' exonuclease activities are essential to release Spo11 from DNA ends, whereas only the endonuclease activity is required for hairpin removal. We also uncovered that MRX-Sae2 endonuclease introduces a cleavage at defined distances from the Spo11-blocked end with gradually decreasing efficiency. Our findings demonstrate that Sae2 stimulates the MRX endo- and exonuclease activities via Rad50 by different mechanisms, ensuring diverse actions of MRX-Sae2 nuclease at DNA ends.

References
1.
ODriscoll M . Diseases associated with defective responses to DNA damage. Cold Spring Harb Perspect Biol. 2012; 4(12). PMC: 3504433. DOI: 10.1101/cshperspect.a012773. View

2.
Bhaskara V, Dupre A, Lengsfeld B, Hopkins B, Chan A, Lee J . Rad50 adenylate kinase activity regulates DNA tethering by Mre11/Rad50 complexes. Mol Cell. 2007; 25(5):647-61. PMC: 3050042. DOI: 10.1016/j.molcel.2007.01.028. View

3.
Li B, Putnam C, Kolodner R . Mechanisms underlying genome instability mediated by formation of foldback inversions in . Elife. 2020; 9. PMC: 7467729. DOI: 10.7554/eLife.58223. View

4.
Wang W, Daley J, Kwon Y, Krasner D, Sung P . Plasticity of the Mre11-Rad50-Xrs2-Sae2 nuclease ensemble in the processing of DNA-bound obstacles. Genes Dev. 2018; 31(23-24):2331-2336. PMC: 5795780. DOI: 10.1101/gad.307900.117. View

5.
Chang H, Pannunzio N, Adachi N, Lieber M . Non-homologous DNA end joining and alternative pathways to double-strand break repair. Nat Rev Mol Cell Biol. 2017; 18(8):495-506. PMC: 7062608. DOI: 10.1038/nrm.2017.48. View