Mechanistic View and Genetic Control of DNA Recombination during Meiosis

Marie-Claude Marsolier-Kergoat (1, 2) , Md Muntaz Khan , Jonathan Schott (3) , Xuan Zhu , Bertrand Llorente (3)

1 I2BC - Institut de Biologie Intégrative de la Cellule
2 EAE - Eco-Anthropologie et Ethnobiologie
3 CRCM - Centre de Recherche en Cancérologie de Marseille

Meiotic recombination is essential for fertility and allelic shuffling. Canonical recombination models fail to capture the observed complexity of meiotic recombinants. Here, by combining genome-wide meiotic heteroduplex DNA patterns with meiotic DNA double-strand break (DSB) sites, we show that part of this complexity results from frequent template switching during synthesis-dependent strand annealing that yields noncrossovers and from branch migration of double Holliday junction (dHJ)-containing intermediates that mainly yield crossovers. This complexity also results from asymmetric positioning of crossover intermediates relative to the initiating DSB and Msh2-independent conversions promoted by the suspected dHJ resolvase Mlh1-3 as well as Exo1 and Sgs1. Finally, we show that dHJ resolution is biased toward cleavage of the pair of strands containing newly synthesized DNA near the junctions and that this bias can be decoupled from the cross-over-biased dHJ resolution. These properties are likely conserved in eukaryotes containing ZMM proteins, which includes mammals.

Domaines: Sciences du Vivant [q-bio]

Marie-Claude Marsolier-Kergoat, Md Muntaz Khan, Jonathan Schott, Xuan Zhu, Bertrand Llorente. Mechanistic View and Genetic Control of DNA Recombination during Meiosis. Molecular Cell, 2018, 70 (1), pp.9+. ⟨10.1016/j.molcel.2018.02.032⟩. ⟨hal-02397018⟩