Asy2/Mer2: an evolutionarily conserved mediator of meiotic recombination, pairing, and global chromosome compaction
- Sophie Tessé1,6,
- Henri-Marc Bourbon2,6,
- Robert Debuchy1,
- Karine Budin1,
- Emeline Dubois1,
- Zhang Liangran3,
- Romain Antoine1,
- Tristan Piolot4,
- Nancy Kleckner5,
- Denise Zickler1 and
- Eric Espagne1
- 1Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS), Commissariat Energie Atomique (CEA), Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France;
- 2Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI) Université de Toulouse, CNRS, 31062 Toulouse, France;
- 3Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, China;
- 4UMR 3215, U934, Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Curie, 75005 Paris, France;
- 5Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Corresponding authors: denise.zickler{at}i2bc.paris-saclay.fr, eric.espagne{at}i2bc.paris-saclay.fr
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↵6 These authors contributed equally to this work.
Abstract
Meiosis is the cellular program by which a diploid cell gives rise to haploid gametes for sexual reproduction. Meiotic progression depends on tight physical and functional coupling of recombination steps at the DNA level with specific organizational features of meiotic-prophase chromosomes. The present study reveals that every step of this coupling is mediated by a single molecule: Asy2/Mer2. We show that Mer2, identified so far only in budding and fission yeasts, is in fact evolutionarily conserved from fungi (Mer2/Rec15/Asy2/Bad42) to plants (PRD3/PAIR1) and mammals (IHO1). In yeasts, Mer2 mediates assembly of recombination–initiation complexes and double-strand breaks (DSBs). This role is conserved in the fungus Sordaria. However, functional analysis of 13 mer2 mutants and successive localization of Mer2 to axis, synaptonemal complex (SC), and chromatin revealed, in addition, three further important functions. First, after DSB formation, Mer2 is required for pairing by mediating homolog spatial juxtaposition, with implications for crossover (CO) patterning/interference. Second, Mer2 participates in the transfer/maintenance and release of recombination complexes to/from the SC central region. Third, after completion of recombination, potentially dependent on SUMOylation, Mer2 mediates global chromosome compaction and post-recombination chiasma development. Thus, beyond its role as a recombinosome–axis/SC linker molecule, Mer2 has important functions in relation to basic chromosome structure.
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Footnotes
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Supplemental material is available for this article.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.304543.117.
- Received July 11, 2017.
- Accepted September 15, 2017.
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