I2BC Paris-Saclay

The GO Paris-Saclay 2021 team won a gold medal and the "Best Inclusivity" prize at the iGEM 2021 international synthetic biology competition on Sunday, November 14.

The team's project "EndoSeek" aims to develop a new diagnostic tool for endometriosis, which is a painful and poorly understood pathology caused by the proliferation of uterine cells outside the uterus. Worldwide, this disease affects about 10% of women and can take up to 7 years to diagnose. Based on preliminary studies using small patient cohorts, certain blood microRNAs (miRNAs) may be biomarkers of the disease.
The team has developed a machine learning program that will allow identification of new endometriosis biomarkers with future cohorts. In experiments conducted this summer at I2BC, students exploited Cas13a and Cas14a1 nucleases for miRNA detection. They created a video game to educate adults and children over the age of 10 about endometriosis and synthetic biology. Finally, following their dialogue with patients and physicians, they questioned the ethical implications of diagnostics.
The team was awarded the Best Inclusivity Award for outstanding efforts to include people with diverse identities. The students thought about the position of LGBT+ people in their project and created a multi-language, voice-assisted website with color customization.
This project was supported by the I2BC, the Faculty of Sciences of the University of Paris-Saclay, La Diagonale Paris-Saclay, EUGLOH (European University Alliance for Global Health), the Graduate School Life Sciences and Health, IDT and Promega.

Team 2021 supervisors included Téo Hébra (ICSN) and 5 members of the I2BC: Philippe Bouloc, Stéphanie Bury-Moné, Emma Piattelli, Ombeline Rossier and Charlène Valadon.
For more information, see the wiki https://2021.igem.org/Team:GO_Paris-Saclay and the video https://video.igem.org/w/ihqYR3UfveimEtZVv7x6jE.

Thanks to the similarity of in-vitro and in-vivo disorganizing effect of statins on cholesterol-rich membrane microdomains, which constitute the cell entry platforms of the various coronaviruses, including SARS-CoV-2, this host-directed therapeutic approach can be proposed to fight against Covid-19.

The entry of SARS-CoV-2, as well as the other coronaviruses, into its target cells is mediated by cholesterol-rich plasma membrane microdomains, whatever the followed pathway. These «lipid rafts» can be destructured in-vitro by the inhibiting action of statins on the key enzyme of cell cholesterol biosynthesis. As a consequence, raft-dependent signaling platforms are disorganized, leading to various cellular effects. In clinics, beyond the classical hypocholesterolemic effect of statins, these drugs can induce various «pleiotropic effects» (anti-inflammatory, immunomodulation, vascular protection...) that are mediated by such signaling platforms. This indicates that statins, administered under clinical situations, are able to in-vivo perturb cholesterol-rich membrane domains, which should include those involved in various pathogenic agents, including SARS-CoV-2, entry platforms. We thus propose statins as a new repurposing strategy against Covid-19, taking into account they are well-known, widely-used safe drugs (used for long-term prevention for high-risk cardio-vascular patients), administered per os, cheap, and overall avoiding any risk of encountering treatment resistances due to viral mutations because it is a «host-directed» therapeutic approach [Orlowski et al, Biochimie 189, 51 (2021)]. It remains to test experimentally this hypothesis.

Contact person: Stephane Orlowski

In a study published in European Biophysics Journal, two teams of the B3S department (INTGEN and MIP) with the PIM platform, in collaboration with national and international experts on molecular scale biophysics compare six approches to measure macromolecular interactions in vitro. The results were obtained in the context of a Training School (ARBRE-MOBIEU COST Action) organized in 2019 in our institute.

Biophysical quantification of protein interactions is central to unveil molecular mechanisms of cellular processes. Researchers can choose from a wide panel of biophysical methods, including classical and more novel ones. A real-life proof-of-concept was carried out during an ARBRE-MOBIEU training school held in June 2019 in Gif-sur-Yvette, France (https://mosbio.sciencesconf.org/). Twenty European students benefited from a one-week training with lessons and practical sessions on six complementary approaches: (i) Analytical UltraCentrifugation with or without a Fluorescence Detector System (AUC-FDS), (ii) Isothermal Titration Calorimetry (ITC), (iii) Size Exclusion Chromatography coupled to Multi-Angle Light Scattering (SEC-MALS), (iv) Bio-Layer Interferometry (BLI), (v) MicroScale Thermophoresis (MST) and, (vi) switchSENSE. They implemented all these methods on two examples of macromolecular interactions: firstly, a protein-protein interaction between an artificial alphaRep binder, and its target protein, also an alphaRep; secondly, a protein-DNA interactionbetween a DNA repair complex, Ku70/Ku80 (hereafter called Ku), and its cognate DNA ligand. The students acknowledged that the workshop provided them with a clearer understanding of the advantages and limitations of the different techniques and will help them in the future to choose the approaches that are most relevant or informative for their projects.

More details here

Contact person: Paloma Fernandez Varela

This is the first published evidence linking lipopolysaccharide structural moiety to neonatal sepsis outcome and opens the possibility of using the 2-hydroxymyristate marker as a detection tool for high-risk patients, which could help reduce their mortality.

Enterobacter cloacae complex species are involved in infections among critically ill patients. After a recent E.cloacae outbreak of fulminant neonatal septic shock, we conducted a study to determine whether septic shock severity and its lethal consequence are related to structural features of the endotoxin (lipopolysaccharide [LPS]) of the strains isolated from hospitalized infants and more specifically its lipid A region. It appeared that the LPSs are very heterogeneous, carrying fifteen different molecular species of lipid A. The virulence was correlated with a structural feature identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry and gas chromatography coupled with mass spectrometry: the presence of 2-hydroxymyristic acid as a secondary substituent in lipid A. This is the first published evidence linking LPS structural moiety to neonatal sepsis outcome and opens the possibility of using this fatty acid marker as a detection tool for high-risk patients, which could help reduce their mortality.

More details here

Contact person: Pierre Tissières

Follow the team

Last call for registration at the Environmental and Agronomical Genomics 2021 Symposium until 13th October.

The Environmental and Agronomical Genomics 2021 symposium will be the opportunity to have an update on most recent environmental genomics research, as well as an overview of high scientific impact projects carried out in collaboration with France Genomique platforms. This year we are also celebrating the 10th anniversary of the GDR Génomique environnementale.

Contact person: Denis Faure

This opinion piece reviews for the first time the evidences across kingdoms that Polycomb (PcG) Repressive Complex 2, thought to be dedicated to the epigenetic silencing of protein-coding genes, can also target, and even silence, transposable elements: could an ancestral role of PcG proteins be to silence transposable elements?

It is generally considered that Polycomb Repressive Complex 2 deposits the histone mark H3K27me3 on silent protein coding genes, while transposable elements are repressed by DNA and/or H3K9 methylation. Yet, there is increasing evidence that the Polycomb repressive complexes also target and even silence transposable elements in representatives of several distantly related eukaryotic lineages. In plants and animals, H3K27me3 is present on transposable elements in mutants and specific cell types devoid of DNA methylation. In this opinion, we summarize the experimental evidence for this phenomenon across the eukaryotic kingdom, and discuss its functional and evolutionary significance. We hypothesize that an ancestral role of Polycomb group proteins was to silence transposable elements.

More details here

Contact person: Angélique Déléris

Follow the team

Interested in confocal microscopy ?
Come to the Imagerie-Gif Confocal Workshop to acquire and reinforce the theoretical basis of photonic microscopy and master the practical use of a full field and confocal microscope !
As well you will be able to integrate the principles and possibilities of new applications and developments in photonic microscopy and understand the complementarities of techniques from conventional microscopy to super-resolution !

Lecture (40% of the time)
- Reminder of conventional microscopy, videomicroscopy
- Introduction to confocal microscopy (instrument physics, acquisition, digitization, sampling, multiple labeling)
- Fast confocal microscope with Nipkow disk (Spinning-Disk)
- Understanding and using fluorochromes in confocal microscopy, proteins and fluorescent probes
- Preparation of live and fixed biological samples
- Processing and use of 2D and 3D images applied to microscopy
- Specific applications in confocal microscopy, FLIM, FRET, etc.
- Increased resolution and super-resolution (PALM, STORM, STED, SIM)
- Application seminars
Practical work (60% of the time)
A cycle of ten practical works over twenty hours will allow to reinforce the link between theory and applications, to recognize the elements implemented, to acquire images, to process them and to analyze them with ImageJ in particular.
One day will also be dedicated to the discovery of advanced techniques such as biphotonic excitation, light sheet microscopy, F-techniques (FRAP, photoactivation) and deconvolution.

More details here

Contact : Mébarek TEMAGOULT

Using different approaches, the group of K. Marheineke in collaboration with A. Goldar (J. Soutourina group) and the proteomics platforms at I2CB and at Necker hospital found a new mechanism of how the kinase Plk1 promotes DNA replication via inhibiting the replication repressor Rif1.

The activation of eukaryotic DNA replication origins needs to be strictly controlled at multiple steps in order to faithfully duplicate the genome and to maintain its stability. How the checkpoint recovery and adaptation protein Polo-like kinase 1 (Plk1) regulates the firing of replication origins during non-challenged S phase remained an open question. Using DNA fiber analysis, the group of Kathrin Marheineke in collaboration with Arach Goldar (J. Soutourina lab) show that immunodepletion of Plk1 in the Xenopus in vitro system decreases replication fork density and initiation frequency. Numerical analyses suggest that Plk1 reduces the overall probability and synchrony of origin firing. We used quantitative chromatin proteomics and co-immunoprecipitations in collaboration with SiCAPS I2BC proteomics platform to demonstrate that Plk1 interacts with firing factors MTBP/Treslin/TopBP1 as well as with Rif1, a known regulator of replication timing. Phosphopeptide analysis by LC/MS/MS show that the C-terminal domain of Rif1, which is necessary for its repressive action on origins through protein phosphatase 1 (PP1), can be phosphorylated in vitro by Plk1 on S2058 in its PP1 binding site. The phosphomimetic S2058D mutant interrupts the Rif1-PP1 interaction and modulates DNA replication. Collectively, our study provides molecular insights into how Plk1 regulates the spatio-temporal replication program and suggests that Plk1 controls origin activation at the level of large chromatin domains in vertebrates.

More details here

Contact persons: Kathrin Marheineke & Arach Goldar

Follow the teams of Kathrin Marheineke and of Arach Goldar

Do you know how bacteria organize their chromosomes allowing key biological processes for the cell? Here we review old and new factors that are essential for the structuring of the bacterial chromosome.

During the last decades, works have shown that bacterial chromosomes are not just molecules of DNA inside a bag composed of lipids, peptidoglycan and proteins. Recent advances have not only confirm the multiscale organization of bacterial chromosome, but also have added new layers on chromosome organization. Briefly, DNA supercoiling is organized into stochastic 10-kb domains included in larger 40–300-kb chromosomal interaction domains (CIDs) delimited by long and highly expressed gene clusters. The bacterial chromatin composed of multiple nucleoid associated proteins (NAPs) bound to DNA not only influences gene expression but also modulates, together with bacterial SMC complexes, the folding and disposition of the chromosome in the cell. Although the main structural layers and their key organizers start to emerge, the complete picture of chromosome organization in bacteria remains elusive. In this article, researchers of the Genome Biology Department of the I2BC review not only the classical well-known factors involved in chromosome organization but also novel components that have recently been shown to dynamically shape the 3D structuring of the bacterial genome.

More details here

Contact person: Frédéric Boccard

Follow the team

The interaction between BRCA2 and its interactor HSF2BP, both required for meiotic recombination, is defined structurally, revealing that a repeat in BRCA2 binds two HSF2BP units, increasing the affinity up to the nanomolar range. Unexpectedly, this repeat is not essential for mouse meiosis.

BRCA2 and its interactors are required for meiotic homologous recombination (HR) and fertility. Loss of HSF2BP, a BRCA2 interactor, disrupts HR during spermatogenesis. We test the model postulating that HSF2BP localizes BRCA2 to meiotic HR sites, by solving the crystal structure of the BRCA2 fragment in complex with dimeric armadillo domain (ARM) of HSF2BP and disrupting this interaction in a mouse model. This reveals a repeated 23 amino acid motif in BRCA2, each binding the same conserved surface of one ARM domain. In the complex, two BRCA2 fragments hold together two ARM dimers, through a large interface responsible for the nanomolar affinity — the strongest interaction involving BRCA2 measured so far. Deleting exon 12, encoding the first repeat, from mBrca2 disrupts BRCA2 binding to HSF2BP, but does not phenocopy HSF2BP loss. Thus, results herein suggest that the high-affinity oligomerization-inducing BRCA2-HSF2BP interaction is not required for RAD51 and DMC1 recombinase localization in meiotic HR.

More details here

Contact person : Sophie Zinn

Follow the team

A combination of genetic screens and mass spectrometry analyses has revealed that an interplay of translational activators and a heterogeneous mitoribosome population balances the production of respiratory complex subunits in fission yeast mitochondria.

Mitochondria contain their own DNA and translation machinery. Mitochondrial mRNAs encode key subunits of the oxidative phosphorylation (OXPHOS) complexes, that produce energy for the whole cell. Thus, mitochondrial translation defects lead to severe diseases in humans. The fission yeast Schizosaccharomyces pombe is a valuable model to study mitochondrial gene expression, since it closely resembles humans in its mitochondrial DNA structure and physiology. By combining bioinformatics, genetic and biochemical approaches including mass spectrometry on the I2BC SICaPS platform, the I2BC BIOMIT group discovered two interacting factors of S. pombe, Cbp7 and Cbp8, controlling the production of Cytb, a catalytic subunit of OXPHOS complex III. Two classes of Cbp7/Cbp8 partners were identified and shown to modulate the synthesis of Cytb or Cox1, key subunits of the OXPHOS complexes III and IV respectively. First, two isoforms of bS1m, a protein of the small mitoribosomal subunit, that appear mutually exclusive and confer translational specificity. Second, a complex of four proteins dedicated to Cox1 synthesis, which includes an RNA helicase, Mrh5, that interacts with the mitochondrial ribosome. These data suggest that S. pombe contains, in addition to complexes of translational activators, a heterogeneous population of mitochondrial ribosomes that could specifically modulate translation depending on the mRNA translated, in order to optimally balance the production of different respiratory complex subunits. Together, these results, published in Nucleic Acids Research, support the view that ribosomes are not merely translation machines, but can also behave as regulatory elements.

 More details here

Contact person : Nathalie Bonnefoy

Follow the team

Mass spectrometry was used to allow the characterization of the biosynthesis of a novel class of phytohormones, striptolactones, in the bryophyte Physcomitrium patens and to compare this processes with the more known vascular plants. Results on Physcomitrium highlight surprising evolutive innovations from vascular plant.

Strigolactones (SL) make up a novel class of phytohormones that are found across the whole land plant lineage. In vascular plants, the main hormonal role of SL is the repression of shoot axillary branching. However, SL are also a major symbiotic signal, granting the plant increased access to the nutrients and water contained in the rhizosphere. These two functions of SL led to the hypothesis that these molecules have been instrumental at the time of land colonization by plants, approximately 450 million years ago. Studying SL biosynthesis and signaling in the bryophyte Physcomitrium patens (P. patens, a non-vascular plant), and comparing these processes with the available knowledge in vascular plants, enables to investigate the evolution of SL cellular pathways in land plants. In angiosperms, the perception of SLs relies on a receptor called D14 (encoded by the same gene family as KAI2) along with the F-box protein MAX2. In moss, Max2 is not required for the SL response although it possesses 13 KAI2-like genes (PpKAI2L). An unusual aspect of SL perception is that the D14 protein is both a receptor and an enzyme that cleaves its substrate (and covalently binds part of the SL) in a signaling mechanism that is still under debate. To further investigate whether PpKAI2L proteins play roles as receptors of SLs and related compounds, we examined the covalent attachment of the artificial SL GR24 isomers to the PpKAI2L proteins by mass spectrometry (MS). Analyses revealed 96 Da increments (corresponding to the D ring mass) when AtKAI2 and PpKAI2L were incubated with GR24 isomers indicating that moss PpKAI2L proteins, like vascular plant receptors, covalently link GR24 enantiomers. As SL signaling is not conserved in P. patens, it appears that the known SL signaling pathway results from a vascular plants specific innovation. Likewise, SL response in P. patens would be the product of a convergent evolution. Therefore, the question as to how P. patens transduces the SL signal, downstream of perception by specific PpKAI2L proteins, remains open.

More details here

Contact person: David Cornu

High throughput analysis of fitness genes in a bacterial pathogen: towards the discovery of new targets to develop treatments.

The pathogenic bacterium Agrobacterium tumefaciens provokes crown-gall disease on a wide diversity of host plants. It colonizes the galls it causes on host plants, poplar and tomato plant for instance. This pathogen also colonizes the roots of host plants and non-host plants, such as maize. We used a genome-wide approach (transposon sequencing) to discover Agrobacterium tumefaciens genes involved in reproductive success on tomato and poplar galls and tomato and maize roots. We used this knowledge to develop plant protection approaches against this pathogen. This wok was supported by the I2BC sequencing platform.

More information here

Contact person: Denis Faure

Appelsprojetsrecherche.fr est un portail à destination des acteurs de la recherche. Inscrit dans le cadre de la Loi de Programmation de la Recherche, il est porté aujourd’hui par six partenaires : l’Ademe, l’ANR, l’ANRS, l’ANSES, l’INCa et l’Inserm. Il offre ainsi un accès unifié aux appels à projets ou à candidatures à venir et en cours, pour une plus grande visibilité de l’offre de financement. Après la date de clôture, les appels restent publiés encore quelques mois.

A fast and yet accurate QT clustering method: BitQT, example of application to MD trajectories

The term clustering designates a comprehensive family of unsupervised learning methods, allowing to group similar elements into sets called clusters. The Quality Threshold (QT) clustering algorithm stands out as an ideal option whenever highly correlated elements are needed to be returned as clusters. QT guarantees that all cluster members will maintain a collective similarity established by a user-defined threshold. Unfortunately, the high computational cost of this algorithm for processing big data limits its application domain. In this work, we proposed a methodological parallel between QT clustering and another well-known algorithm in Graph Theory, the Maximum Clique Problem. We targeted Molecular Dynamics (MD) trajectories as an object of study, by representing molecular conformations as nodes of a graph whose edges imply a mutual similarity between conformations. Using a binary-encoded similarity matrix coupled to the exploitation of bitwise operations to extract clusters significantly contributed to reaching a very affordable algorithm compared to the few implementations of QT for MD available in the literature. Our alternative provides results in good agreement with the exact one, while strictly preserving the collective similarity of clusters. We believe methodological parallels discussed here may be translated to other areas where the QT hallmarks are helpful (e.g. transcriptomics).

More details here

Contact person: Fabrice Leclerc

Follow the team

Characterization of the Radiation Desiccation Response
Regulon of the Radioresistant Bacterium Deinococcus
radiodurans by Integrative Genomic Analyses

Numerous genes are overexpressed in the radioresistant bacterium Deinococcus radiodurans after exposure to radiation or prolonged desiccation. It was shown that the DdrO and IrrE proteins play a major role in regulating the expression of approximately twenty genes. At present, many questions remain, such as the number of genes regulated by the DdrO regulator. Here, we present the first ChIP-seq analysis performed at the genome level in Deinococcus species coupled with RNA-seq, which was achieved in the presence or not of DdrO. We also resequenced our laboratory stock strain of D. radiodurans R1 ATCC 13939 to obtain an accurate reference for read alignments and gene expression quantifications. We highlighted genes that are directly under the control of this transcriptional repressor and showed that the DdrO regulon in D. radiodurans includes numerous other genes than those previously described, including DNA and RNA metabolism proteins. These results thus pave the way to better understand the radioresistance pathways encoded by this bacterium and to compare the stress-induced responses mediated by this pair of proteins in diverse bacteria.

More details here

Contact person: Fabrice Confalonieri

Follow the team

Uncovering the complete building plan and assembly pathway of a viral DNA delivery device

Siphoviruses are the major killers of bacteria. A long non-contractile tail is the key device of these bacteriophages to recognize specifically the host cell and to deliver their viral dsDNA to the bacterial cytoplasm. Furthermore, bacteria use nanotubes homologous to phage long tails to attack other cells. Although structures of these megadalton protein complexes are available, significantly less is known on the molecular mechanisms leading to their assembly.

In a study published in J Mol Biol, I2BC researchers and their collaborators have undertaken a comprehensive analysis of the complete molecular organization of the siphovirus SPP1 tail, which infects Bacillus subtilis, and its biogenesis mechanisms. During tail assembly, the association of proteins follows a strict order. This implies that the third component of a complex does not bind until the first two proteins interact together and so on. Characterization of assembly intermediates from mutants deficient in each of the tail components revealed the sequential program of interactions leading to the construction of the SPP1 tail (~6.8 MDa). All proteins engaged, with the probable exception of one (gp22), are required for assembly. They likely represent the minimal protein set required to construct functional long tails. Bioinformatics analysis highlighted the structural plasticity of these tail components, a source of variability and innovation for the functional diversification of this type of nanotube.

More details here

Contact: Isabelle.Auzat or Paulo Tavares

Follow the team

First experimental evidence for type I-B CRISPR-Cas system adaptation in the emerging human enteropathogen C. difficile and a functional link between the adaptation and interference CRISPR machineries sharing similar tri-nucleotide PAM motif for recognition of foreign nucleic acid sequences.

CRISPR-Cas systems provide prokaryotes with adaptive immunity for defense against foreign nucleic acid invaders, such as viruses or phages and plasmids. The CRISPR-Cas systems are highly diverse, and detailed studies of individual CRISPR-Cas subtypes are important for our understanding of various aspects of microbial adaptation strategies and for the potential applications. The significance of this collaborative work of French, Russian and US labs from I2BC, Skoltech and Waksman Institute of Microbiology is in providing the first experimental evidence for type I-B CRISPR-Cas system adaptation in the emerging human enteropathogen Clostridioides difficile. This bacterium needs to survive in phage-rich gut communities, and its active CRISPR-Cas system might provide efficient antiphage defense by acquiring new spacers within CRISPR arrays that constitute memory for further invader elimination. This study also reveals a functional link between the adaptation and interference CRISPR machineries. The definition of all possible functional trinucleotide motifs upstream protospacers within foreign nucleic acid sequences is important for CRISPR-based genome editing in this pathogen and for developing new drugs against C. difficile infections.

More details here

Contact person: Olga Soutourina

Follow the team

A joint collaborative effort of the Microbiology, Genome Biology Departments and the Sequencing Facility of the I2BC unveiled the dynamics of the linear chromosome of Streptomyces ambofaciens, during metabolic differentiation.

Streptomyces are soil bacteria mostly known for their complex life cycle (uni- to multi-cellular transition, sporulation, metabolic differentiation) and their prolific specialized metabolism (e.g. antibiotics and pigments), widely exploited in medicine, agriculture and the food industry. Their genome possesses remarkable characteristics including a large size (6-12 Mb) and a high GC content (circa 72%) and, even more unusual in bacteria, a linear configuration. Interestingly, Streptomyces chromosomes present a remarkable genetic compartmentalization, with a distinguishable central region harboring core genes and two terminal regions enriched in specialized metabolite biosynthetic gene clusters. The molecular mechanisms governing the structure and function of these compartmentalized chromosomes remain mostly unknown. In this work, teams of the Genome Biology, the Microbiology Department and the Sequencing Facility of the I2BC in collaboration with the DynAMIC (Lorraine University -INRAe) and the TIMC-IMAG ( Grenoble Alpes University - CNRS) Institutes, show that chromosome structure in Streptomyces ambofaciens correlates with genetic compartmentalization during exponential phase. Conserved, large and highly transcribed genes form boundaries that segment the central part of the chromosome into domains, whereas the terminal ends tend to be transcriptionally quiescent compartments with different structural features. The onset of metabolic differentiation is accompanied by a rearrangement of the chromosome architecture, from a rather ‘open’ to a ‘closed’ conformation, in which highly expressed specialized metabolite biosynthetic genes form new domain boundaries. Altogether, these results indicate that the linear chromosome of S. ambofaciens is partitioned into structurally distinct entities, suggesting a link between chromosome folding, gene expression and genome evolution.

More details here

Contact persons: Virginia Lioy & Stephanie Bury-Mone

Follow the team

The study reports the CryoEM structures of the core proteins involved in the human NHEJ pathway that repair most DNA double-strand breaks generated in human cells.

Double strand breaks (DSB) are the most toxic DNA lesions in the cell. The Non-homologous end-joining pathway is the main DNA repair pathway in mammals that recognizes, process and ligates DSB. It is initiated by the recognition of DSB by the heterodimer Ku70/80 and the kinase DNA-PKcs that can form a synapse between the two DNA ends of the DSB. Ku70/80 then recruits several enzymatic activities to process and ligate the DNA ends. A team from B3S I2BC collaborates with TL Blundell laboratory (University of Cambridge) to determine cryoEM structure at 4.3Angstrom of the synapse formed by Ku70/80, DNA-PKcs, the ligation complex Ligase4/XRCC4/XLF. This super-complex show a central role of XLF that bridges Ku70/80 and Ligase4/XRCC4 on both side of the synapse. Mutations of the dimer interfaces negatively affect DNA repair.

More details here

Contact person : Jean-Baptiste Charbonnier

Follow the team