Spatiotemporal control of DNA double strand break formation in mammalian germ cells by a newly discovered meiosis-specific protein, ANKRD31
General Genetics and Functional Genome Biology
Final Report Abstract
DNA double-strand-breaks (DSB) are major contributors to genome instability, deleterious mutations and cancer. Yet, programmed formation of several hundred DSBs is an essential part of meiosis, as DSBs serve to initiate homologous meiotic recombination. Recombination-mediated repair of DSBs generates crossovers, which are indispensable for correct segregation of homologous chromosomes and thus the generation of haploid gametes. Anomalies in recombination cause aneuploidies and infertility in humans, and persistent DSBs are potentially genotoxic. Yet, the mechanism of DSB control has been poorly understood. Mammalian genomes have several thousand sites which are prone to frequent DSB formation during meiosis. These DSB hotspots are thought to depend on “open” chromatin marks such as tri-methylation of lysine4 (H3K4me3) and lysine 36 (H3K36me3) in histone H3. Curiously, active promoters and genes, which carry these marks, do not act as hotspots in wild-type. DSB forming activity is uniquely strong at homologous pseudoautosomal regions (PARs) of X and Y chromosomes, and hotspots depend on distinct factors in PARs and the rest of the genome (non-PAR hotspots). The positions of non-PAR hotspots are defined by PRDM9, which binds hotspot sites and locally catalyses H3K4me3 and H3K36me3 modifications. The combination of these histone modifications and PRDM9-binding is thought to recruit the DSB-forming machinery, represented by multiprotein DSB-factor clusters. In contrast to non-PAR hotspot, PARs do not require PRDM9 for DSBs. We identified a hitherto unknown meiosis-specific protein, ANKRD31, that colocalizes with chromatin-bound DSB- factor clusters. We found that ANKRD31-deficient mice have a severe delay in DSB formation and an abnormal hotspot distribution. DSBs form both at conventional non-PAR hotspots and also, aberrantly, at active promoters. Uniquely, DSB formation seems to be severely reduced at PARs. Given these observations we aimed to gain new insights into the control of meiotic DSBs by focusing on ANKRD31 and its interplay with other DSB factors. Our data suggest that ANKRD31 acts as a scaffold for DSB factor clusters. ANKRD31 enhances both the seeding and the growth of DSB-factor clusters, complementing a pathway that specifically enhances seeding and that depends on the DSB-promoting HOR- MAD1/IHO1 proteins. Thus, we show that DSBs are ensured by genetically separable pathways that differentially support seeding and growth of DSB-machinery clusters on chromatin. Additionally, we uncovered negative feedback mechanisms that prevent excessive DSBs via destabilization of DSB-factor clusters. Thus, the project elucidated key mechanisms controlling DSB formation in mammals, relevant to human reproductive biology.
Publications
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Mouse ANKRD31 Regulates Spatiotemporal Patterning of Meiotic Recombination Initiation and Ensures Recombination between X and Y Sex Chromosomes. Molecular Cell, 74(5), 1069-1085.e11.
Papanikos, Frantzeskos; Clément, Julie A.J.; Testa, Erika; Ravindranathan, Ramya; Grey, Corinne; Dereli, Ihsan; Bondarieva, Anastasiia; Valerio-Cabrera, Sarai; Stanzione, Marcello; Schleiffer, Alexander; Jansa, Petr; Lustyk, Diana; Fei, Ji-Feng; Adams, Ian R.; Forejt, Jiri; Barchi, Marco; de Massy, Bernard & Toth, Attila
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Four-pronged negative feedback of DSB machinery in meiotic DNA-break control in mice. Nucleic Acids Research, 49(5), 2609-2628.
Dereli, Ihsan; Stanzione, Marcello; Olmeda, Fabrizio; Papanikos, Frantzeskos; Baumann, Marek; Demir, Sevgican; Carofiglio, Fabrizia; Lange, Julian; de Massy, Bernard; Baarends, Willy M.; Turner, James; Rulands, Steffen & Tóth, Attila
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Seeding the meiotic DNA break machinery and initiating recombination on chromosome axes. Nature Communications, 15(1).
Dereli, Ihsan; Telychko, Vladyslav; Papanikos, Frantzeskos; Raveendran, Kavya; Xu, Jiaqi; Boekhout, Michiel; Stanzione, Marcello; Neuditschko, Benjamin; Imjeti, Naga Sailaja; Selezneva, Elizaveta; Tuncay, Hasibe; Demir, Sevgican; Giannattasio, Teresa; Gentzel, Marc; Bondarieva, Anastasiia; Stevense, Michelle; Barchi, Marco; Schnittger, Arp; Weir, John R. ... & Tóth, Attila
