Ufd2p promotes meiotic crossover formation by destabilizing Top2p in budding yeast

Meiotic crossover (CO) serves dual essential roles in ensuring accurate chromosome segregation and generating genetic diversity. While protein ubiquitination has been implicated in meiotic CO formation, the specific E3 ligases involved and their molecular mechanisms remain largely characterized. Through systematic screening, we identified Ufd2p as a key meiotic CO regulator. Depletion of Ufd2p severely impaired meiotic recombination by reducing CO numbers and enhancing CO interference strength. Multi-omics analysis identified topoisomerase II (Top2p) as a specific substrate of Ufd2p, and Ufd2p could catalyze Top2p ubiquitination to promote its degradation through ubiquitin-proteasome pathway. Accumulated Top2p in Ufd2p depletion strains resolves DNA negative supercoils, which in turn enhances CO interference strength and reduces CO numbers. Remarkably, expression of either mouse or human UBE4B in yeast effectively rescued the meiotic and recombination defects caused by Ufd2p depletion. These findings provide important insights into the ubiquitin-mediated regulatory network governing chromatin structure and meiotic recombination pattern Overall design: Wild type(UFD2-9MYC) cells were induced to synchronously enter meiosis and samples were collected at 4h in SPM and fixed with 1% formaldehyde for chromatin crosslinking and mechanically lysed using glass beads. Chromatin fragments were sonicated to 200-500 bp, followed by overnight incubation with mouse monoclonal anti-Myc antibodies and Protein A/G magnetic beadsl After sequential washing, immunoprecipitated complexes were eluted and reverse-crosslinked. DNA purification was conducted using the QIAquick PCR Purification Kit. Libraries were prepared and sequenced in paired-end 150-bp (PE150) mode on an Illumina platform.