Evolutionary conservation of the structure and function of meiotic Rec114−Mei4 and Mer2 complexes
- Dima Daccache1,
- Emma De Jonge1,
- Pascaline Liloku1,
- Karen Mechleb1,
- Marita Haddad1,
- Sam Corthaut2,
- Yann G.-J. Sterckx2,
- Alexander N. Volkov3,4 and
- Corentin Claeys Bouuaert1
- 1Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-La-Neuve, Belgium;
- 2Laboratory of Medical Biochemistry (LMB), the Infla-Med Centre of Excellence, University of Antwerp, 2610 Wilrijk, Belgium;
- 3Vlaams Instituut voor Biotechnologie (VIB)-Vrije Universiteit Brussel (VUB) Center for Structural Biology, VIB, 1050 Brussels, Belgium;
- 4Jean Jeener NMR Centre, Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Corresponding authors: corentin.claeys{at}uclouvain.be, ovolkov{at}vub.be
Abstract
Meiosis-specific Rec114−Mei4 and Mer2 complexes are thought to enable Spo11-mediated DNA double-strand break (DSB) formation through a mechanism that involves DNA-dependent condensation. However, the structure, molecular properties, and evolutionary conservation of Rec114−Mei4 and Mer2 are unclear. Here, we present AlphaFold models of Rec114−Mei4 and Mer2 complexes supported by nuclear magnetic resonance (NMR) spectroscopy, small-angle X-ray scattering (SAXS), and mutagenesis. We show that dimers composed of the Rec114 C terminus form α-helical chains that cup an N-terminal Mei4 α helix, and that Mer2 forms a parallel homotetrameric coiled coil. Both Rec114−Mei4 and Mer2 bind preferentially to branched DNA substrates, indicative of multivalent protein–DNA interactions. Indeed, the Rec114−Mei4 interaction domain contains two DNA-binding sites that point in opposite directions and drive condensation. The Mer2 coiled-coil domain bridges coaligned DNA duplexes, likely through extensive electrostatic interactions along the length of the coiled coil. Finally, we show that the structures of Rec114−Mei4 and Mer2 are conserved across eukaryotes, while DNA-binding properties vary significantly. This work provides insights into the mechanism whereby Rec114−Mei4 and Mer2 complexes promote the assembly of the meiotic DSB machinery and suggests a model in which Mer2 condensation is the essential driver of assembly, with the DNA-binding activity of Rec114−Mei4 playing a supportive role.
Keywords
- DNA double-strand break
- S. cerevisiae
- biomolecular condensation
- meiotic recombination
- multivalent protein–DNA interactions
- protein structure
Footnotes
-
Supplemental material is available for this article.
-
Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.350462.123.
- Received January 22, 2023.
- Accepted June 22, 2023.
This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first six months after the full-issue publication date (see http://genesdev.cshlp.org/site/misc/terms.xhtml). After six months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.