Corentin Claeys Bouuaert

RPA directly stimulates Mer3/HFM1 helicase processivity to ensure normal crossover formation in meiosis Meiotic crossover formation is critical for generating viable gametes and enhancing genetic diversity. The helicase Mer3 (HFM1 in humans) is a highly conserved factor essential for promoting crossover...

www.biorxiv.org/content/10.1...

We are hiring!
We are looking for a motivated and enthusiastic postdoc to study mammalian DSB repair using innovative genomic approaches.
Our lab is at the Curie Institute in Paris and offers vibrant scientific environnement and cutting edge platforms.
Please repost or apply here:
lnkd.in/eJ9q3QrR

We found a new asymmetry in the large-scale chromosome structure: sister chromatids are systematically shifted by hundreds of kb in the 5′→3′ direction of their inherited strands! The work was led by Flavia Corsi, in close collaboration with the Daniel Gerlich lab.
www.biorxiv.org/content/10.1...
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Thank you Valérie!

We’re happy to present a new preprint from the lab, where we identify new mechanisms that drive the recruitment of Mre11 to recombination sites during meiosis. Work led by star student Priyanka Priyadarshini with help from colleagues and funded by the ERC and FNRS.

www.biorxiv.org/content/10.1...

We’re happy to present a new preprint from the lab, where we identify new mechanisms that drive the recruitment of Mre11 to recombination sites during meiosis. Work led by star student Priyanka Priyadarshini with help from colleagues and funded by the ERC and FNRS.

www.biorxiv.org/content/10.1...

Diagram of two types of reproduction based on their meiosis. A. shows typical meiosis taking place in individuals with two copies of each chromosome (diploids) resulting in both male and female gametes carrying one copy of each chromosome. Fertilization restores the double copy for each chromosome. B. shows Canina meiosis in individuals carrying five copies of each chromosome (pentaploids) where male gametes only carry one copy of each chromosome and female gametes carry four copies of each chromosome. Fertilization restores the five copy for each chromosome.

Check out the Views & News piece that Joiselle Fernandes and I wrote for @nature.com on the recent work from @amarques.bsky.social and colleagues about one of the most bizarre ways to do meiosis rdcu.be/euabu.

Explained for non-experts!

Crossover patterning through condensation and coarsening of pro-crossover factors Nature Cell Biology - Zhang et al. provide evidence that, during meiosis, recombination proteins assemble into active droplets, the coarsening of which partially explains the phenomenon of...

Very happy (and frankly relieved) to see this paper finally out in peer-reviewed form. (Preprint was posted in August 2021, but this is the world we live in now). rdcu.be/erMk6

Maximizing meiotic crossover rates reveals the map of Crossover Potential - Nature Communications Meiotic crossovers enhance genetic diversity in sexually reproducing organisms. Here, the authors propose that the higher-order spatial organization of the meiotic chromosomes shapes sexual dimorphism...

Paper alert! #Meiosis4Ever

Maximizing meiotic crossover rates reveals the map of Crossover Potential

Juli Jing, Qiachao Lian and Stephanie Durand
www.nature.com/articles/s41...

We pushed meiotic crossover as much has we could, and had some surprises

A thread 👇

SPO11 dimers are sufficient to catalyse DNA double-strand breaks in vitro - Nature A biochemical system recapitulates the hallmarks of meiotic double-strand break formation, with mouse SPO11 catalysing break formation in the absence of any partners and remaining covalently atta...

Here is a link to the initial paper, in case you missed it.

www.nature.com/articles/s41...

In Vitro Reconstitution of SPO11-Mediated DNA Cleavage Sheds New Light on the Initiation of Meiotic Recombination | DNA and Cell Biology Three recent studies report the first biochemical reconstitution of DNA double-strand break (DSB) formation by SPO11, the topoisomerase-derived transesterase that initiates meiotic recombination in sexually reproducing organisms. A central conclusion of these studies is that SPO11 is sufficient to catalyze DSBs in vitro, but cleavage is limited by the poor propensity of SPO11 to dimerize, thereby providing an effective mechanism to prevent uncontrolled breaks. The studies yield new insights into the mechanism of DNA DSB formation and raise new questions regarding the functions of SPO11 partners, the impact of the DNA substrate, the coordination between cleavage events, and the reversibility of the reaction.

For your consideration, here is a short article where Cédric Oger and I reflect on our recent paper reporting the in vitro reconstitution of DNA cleavage by SPO11, and discuss some of the implications of this work.

The paper is available in open access.

www.liebertpub.com/doi/10.1089/...

Please see our latest paper on the role of EXO1 in meiosis: "EXO1 promotes the meiotic MLH1-MLH3 endonuclease through conserved interactions with MLH1, MSH4 and DNA". Congratulations to both first authors, Megha Roy and Aurore Sanchez and thanks to all our collaborators!

Excited to share our preprint on the molecular architecture of heterochromatin in human cells 🧬🔬w/ @jpkreysing.bsky.social, @johannesbetz.bsky.social,
@marinalusic.bsky.social, Turoňová lab, @hummerlab.bsky.social @becklab.bsky.social @mpibp.bsky.social

🔗 Preprint here tinyurl.com/3a74uanv

Intercellular bridges are essential for transposon repression and meiosis in the male germline - Nature Communications A conserved feature of metazoan meiosis is that it occurs in a syncytium. Here, the authors show that intercellular bridges that connect germ cells in a syncytium are critical for ensuring proper meio...

For my first science post here, I’m proud to advertise our latest work exploring why germ cell connectivity is really important for meiosis 🐁

Done with some awesome colleagues @florpratto.bsky.social

www.nature.com/articles/s41...

G-quadruplex–stalled eukaryotic replisome structure reveals helical inchworm DNA translocation DNA G-quadruplexes (G4s) are non–B-form DNA secondary structures that threaten genome stability by impeding DNA replication. To elucidate how G4s induce replication fork arrest, we characterized fork ...

How do replisomes walk on DNA? And what happens when they run into a G-quadruplex? @sahilbatra.bsky.social and @benallwein.bsky.social provide unexpected insight in our latest paper with Richard Hite @mskcancercenter.bsky.social @science.org www.science.org/doi/10.1126/.... Congrats to all authors!

Thanks Anton!

Thank you Takashi!

Thank you Petr!

SPO11 is meiosis-specific and breaks are usually repaired by recombination. However, SPO11 (and other meiosis proteins) are often expressed in cancers for some reason.

the version of record (VoR) of our most recent paper has been published @elife.bsky.social! 🎉🥳 🧪

elifesciences.org/articles/102...

Thank you!!

Thanks, Needhi!

Reconstitution of SPO11-dependent double-strand break formation - Nature Reconstitution of recombinantly expressed SPO11–TOP6BL complex recapitulates its DNA cleavage function and together with structural modelling and biochemical experiments, provides insights into the re...

Also see two accompanying papers by the labs of Scott Keeney and Ming-Han Tong reporting similar findings, focusing on the SPO11-TOP6BL complex.
www.nature.com/articles/s41...
www.nature.com/articles/s41...

And here is a nice News&views by Mendez Diaz and Corbett.
www.nature.com/articles/d41...

Big shoot-out to first author Cédric Oger for getting this in vitro system to work. This work was funded by a starting grant from the European Research Council and by the Fonds National de la Recherche Scientifique. #ERCResearch @frsFNRS

Adding to this model, we now propose that condensates recruit SPO11-TOP6BL complexes, thereby increasing local SPO11 concentration, allowing dimerization and cleavage.

DNA-driven condensation assembles the meiotic DNA break machinery - Nature During meiosis, Mer2 and the Rec114–Mei4 complex form condensates that facilitate the formation of double-strand DNA breaks by recruiting the Spo11 transesterase complex.

SPO11 cleavage also depends on other partners in vivo, including RMMI. We previously showed that the yeast orthologs undergo DNA-dependent condensation.
www.nature.com/articles/s41...

SPO11 and its partner TOP6BL form a 1:1 complex of similar cleavage activity to SPO11 alone, although dependent on the experimental condition. SPO11-TOP6BL complexes bind DNA ends with high affinity, suggesting a possible role after cleavage, while SPO11 alone does not.

In vivo, SPO11 requires multiple other partners. These are dispensable in vitro because SPO11 monomers can dimerize at high protein concentration, probably through direct encounters on the DNA substrate.

In conditions that accumulate single-strand nicks, we detect a weak plasmid relaxation activity, likely caused by dissociation of the SPO11 dimer interface, swiveling around the intact strand, and re-ligation. Hence, cleavage is inherently reversible.