PolySUMOylation of PCNA and Rad52 restricts centromeric recombination in fission yeast
- Katarzyna Markowska
- Ireneusz Litwin
- Dorota Misiorna
- Julia Kończak
- Aleksandra Bogdańska
- Paulina Tomaszewska
- Michał Tracz
- Mika Haenen
- Karol Kramarz
2025-12-02
SUMOylation, a conserved post-translational modification in eukaryotes, regulates protein function, localization, and stability. However, the role of SUMO chains in genome maintenance is still emerging. Using Schizosaccharomyces pombe , we show that loss of SUMO chains results in spontaneous replication stress, DNA damage, and elevated centromeric recombination. To investigate SUMO-dependent interactome at the sites of Rad52 repair, we used a split-SUMO-ID proteomics approach. It allows the analysis of local SUMOylation content at the Rad52 repair sites, and enabled the identification of the essential replication factor PCNA. We found that SUMO chain-modified PCNA antagonizes Rad8-mediated PCNA polyubiquitination, modulating the choice of post-replication repair pathways at stalled forks within centromeres. In the absence of polySUMOylation, excessive PCNA polyubiquitination drives elevated recombination at centromeres. Artificial tethering of a SUMO chain to Rad52 suppresses this defect. Our findings uncover an essential role for SUMO chains in centromere maintenance by modulating DNA repair pathway choice under endogenous replication stress.