TY - JOUR T1 - PRDM9 forms a multiprotein complex tethering recombination hotspots to the chromosomal axis JF - bioRxiv DO - 10.1101/056713 SP - 056713 AU - Emil D. Parvanov AU - Hui Tian AU - Timothy Billings AU - Ruth L. Saxl AU - Rakesh Aithal AU - Lumir Krejci AU - Kenneth Paigen AU - Petko M. Petkov Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/06/02/056713.abstract N2 - In mammals, meiotic recombination occurs at 1-2 kb genomic regions termed hotspots, whose positions and activities are determined by PRDM9, a DNA-binding histone methyltransferase. We now show that the KRAB domain of PRDM9 binds additional proteins into complexes that bring hotspots into the next phase of recombination. By a combination of yeast-two hybrid assay, in vitro binding, and co-immunoprecipitation from mouse spermatocytes, we identified four proteins that directly interact with PRDM9's KRAB domain, CXXC1, EWSR1, EHMT2, and CDYL. These proteins are co-expressed in spermatocytes at the early stages of meiotic prophase I to which PRDM9 expression is restricted. We also detected association of PRDM9-bound complexes with the meiotic cohesin REC8 and the synaptonemal complex proteins SYCP3 and SYCP1. Our results suggest a model in which PRDM9-bound hotspot DNA is brought to the chromosomal axis by the action of these proteins, which also ensure proper chromatin and spatial environment for the subsequent recombination events. Double-strand breaks are initiated on the chromosomal axis; homology search and their subsequent repair are restricted to the synaptonemal complex space.SUMMARY STATEMENT This paper shows how the recombination regulator PRDM9 brings the hotspot DNA to the chromosomal axis to facilitate meiotic recombination initiation ER -