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bioRxiv · 10.1101/2023.11.08.566226

Cohesin complex oligomerization maintains end-tethering at DNA double-strand breaks

Phipps, J.·Toulouze, M.·Ducrot, C.·Costa, R.·Brocas, C.·Dubrana, K.
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Abstract

DNA double-strand breaks (DSB) must be repaired to ensure genome stability. Crucially, DSB ends must be kept together for timely repair. In Saccharomyces cerevisiae, two poorly understood pathways mediate DSB end-tethering. One employs the Mre11-Rad50-Xrs2 (MRX) complex to physically bridge DSB ends. Another requires the conversion of DSB ends into single-strand DNA (ssDNA) by Exo1, but the bridging proteins are unknown. We uncover that cohesin, its loader and Smc5/6 act with Exo1 to tether DSB ends. Remarkably, cohesin specifically impaired in oligomerization fails to tether DSB ends, revealing a new function for cohesin oligomerization. In addition to the known importance of sister chromatid cohesion, microscopy-based microfluidic experiments unveil a new role for cohesin in repair by ensuring DSB end-tethering. Altogether, our findings demonstrate that oligomerization of cohesin prevents DSB end separation and promotes DSB repair, revealing a novel mode of action and role for cohesin in safeguarding genome integrity.

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Phipps, J., Toulouze, M., Ducrot, C., Costa, R., Brocas, C., Dubrana, K.. 2023-11-08. Cohesin complex oligomerization maintains end-tethering at DNA double-strand breaks. https://doi.org/10.1101/2023.11.08.566226

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