Negative supcoils pattern meiotic crossovers

Interference exists ubiquitously in many biological processes. Crossover interference patterns meiotic crossovers, which are required for faithful chromosome segregation and evolutionary adaption. However, what the interference signal is and how it is generated and regulated are unknown. We show that yeast top2 alleles cannot bind or cleave DNA accumulate a higher level of negative supercoils and show weaker interference. However, top2 alleles cannot religate the cleaved DNA or release the religated DNA accumulate less negative supercoils and show stronger interference. Moreover, the level of negative supercoils is negatively correlated with crossover interference strength in various strains. Furthermore, negative supercoils preferentially enrich at crossover-associated Zip3 regions before the formation of meiotic DNA double-strand breaks, and regions with more negative supercoils tend to have more Zip3. Additionally, the strength of crossover interference and homeostasis change coordinately in mutants. These findings suggest that the accumulation and relief of negative supercoils pattern meiotic crossovers. ChIP-seq analysis of binding of TMP(marker of negative supercoils) in S. cerevisiae during meiosis. Total 36 samples were analyzed. ChIP: 3 time point(3, 4 and 5h in SPM) from WT, spo11-Y135F, pCLB2-TOP2, top2-L475A and fragmental DNA of WT (negative control; 4h in SPM) . Input: 4h in SPM from WT, spo11-Y135F, pCLB2-TOP2, top2-L475A and fragmental DNA of WT(negative control; 4h in SPM). Each sample was with two biological repeats.