RT Journal Article SR Electronic T1 PRDM9 forms a multiprotein complex tethering recombination hotspots to the chromosomal axis JF bioRxiv FD Cold Spring Harbor Laboratory SP 056713 DO 10.1101/056713 A1 Emil D. Parvanov A1 Hui Tian A1 Timothy Billings A1 Ruth L. Saxl A1 Rakesh Aithal A1 Lumir Krejci A1 Kenneth Paigen A1 Petko M. Petkov YR 2016 UL http://biorxiv.org/content/early/2016/06/02/056713.abstract AB 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