Meiotic recombination cold spots in chromosomal cohesion sites

Meiotic chromosome architecture called ‘axis–loop structures’ and histone modifications have been shown to regulate the S po11‐dependent formation of DNA double‐strand breaks ( DSB s) that trigger meiotic recombination. Using genome‐wide chromatin immunoprecipitation ( C h IP ) analyses followed by deep sequencing, we compared the genome‐wide distribution of the axis protein R ec8 (the kleisin subunit of meiotic cohesin) with that of oligomeric DNA covalently bound to S po11, indicative of DSB sites. The frequency of DSB sites is overall constant between R ec8 binding sites. However, DSB cold spots are observed in regions spanning ±0.8 kb around R ec8 binding sites. The axis‐associated cold spots are not due to the exclusion of S po11 localization from the axis, because C h IP experiments showed that substantial S po11 persists at R ec8 binding sites during DSB formation. S po11 fused with G al4 DNA binding domain ( G al4 BD ‐ S po11) tethered in close proximity (≤0.8 kb) to R ec8 binding sites hardly forms meiotic DSB s, in contrast with other regions. In addition, H 3 K 4 trimethylation ( H 3 K 4me3) remarkably decreases at Rec8 binding sites. These results suggest that reduced histone H 3 K 4me3 in combination with inactivation of S po11 activity on the axis discourages DSB hot spot formation.