Spo11-Accessory Proteins Link Double-Strand Break Sites to the Chromosome Axis in Early Meiotic Recombination

SummaryMeiotic recombination between homologous chromosomes initiates via programmed DNA double-strand breaks (DSBs), generated by complexes comprising Spo11 transesterase plus accessory proteins. DSBs arise concomitantly with the development of axial chromosome structures, where the coalescence of axis sites produces linear arrays of chromatin loops. Recombining DNA sequences map to loops, but are ultimately tethered to the underlying axis. How and when such tethering occurs is currently unclear. Using ChIPchip in yeast, we show that Spo11-accessory proteins Rec114, Mer2, and Mei4 stably interact with chromosome axis sequences, upon phosphorylation of Mer2 by S phase Cdk. This axis tethering requires meiotic axis components (Red1/Hop1) and is modulated in a domain-specific fashion by cohesin. Loss of Rec114, Mer2, and Mei4 binding correlates with loss of DSBs. Our results strongly suggest that hotspot sequences become tethered to axis sites by the DSB machinery prior to DSB formation.

Graphical AbstractFigure optionsDownload high-quality image (269 K)Download as PowerPoint slideHighlights
► Pre-DSB recombinosome components Rec114, Mer2, and Mei4 bind to chromosome axis sites
► Binding requires S phase Cdk and axial element components and is modulated by cohesion
► Loss of axis site binding correlates with loss of DSBs in budding yeast
► The DSB machinery may link hotspots to axis sites prior to DSB formation