Genome-wide binding site of Rec10 and Rec15 during meiosis

Higher-order chromosome structure is assumed to control various DNA-templated reactions in eukaryotes. Meiotic chromosomes implement developed structures called “axes” and “loops”; both are suggested to tether each other, activating Spo11 to catalyze meiotic DNA double-strand breaks (DSBs) at recombination hotspots. We found that the Schizosaccharomyces pombe Spo11 homolog Rec12 and its partners form two distinct subcomplexes, DSBC (Rec6-Rec12-Rec14) and SFT (Rec7-Rec15-Rec24). Additionally, Mde2, whose expression is strictly regulated by the replication checkpoint, interacts with a component of each subcomplex. The SFT subcomplex binds to both axes via direct interaction of Rec15 with Rec10 in axes and DSB sites, hence axial Rec10 can partially tether DSB sites located in loops. Importantly, this multiprotein-based tethered axis-loop complex is destabilized in the absence of Mde2. We therefore propose a novel mechanism by which Mde2 functions as a recombination initiation mediator to tether axes and loops, in liaison with the meiotic replication checkpoint. ChIP-chip analyses of Rec10 (in wild type), Mde2 (in wild type and rec15∆), and Rec15 (in wild type, rec10∆, rec24∆ and mde2∆) at meiosis 4 hours.