Expertise

Hub members Have many expertise, covering most of the fields in bioinformatics and biostatistics. You'll find below a non-exhaustive list of these expertise

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Searched keyword : Sequence analysis

Related people (18)

Emna ACHOURI


Emna has joined the C3BI in 2016 and worked actively in the IGDA platform doing research and education. Now, she is also part of the Viral Populations and Pathogenesis Unit (PVP).


Keywords
Genome assemblySequence analysisProgram developmentData integrationRead mappingLIMSParallel computingGene predictionShotgun metagenomics
Organisms

Projects (1)

Claudia CHICA


As a computational biologist I have been involved in various projects seeking to answer different biological questions. Those projects have allowed me to define my main research interest, namely the evolutionary study of the emergence, storage and modulation of information in biological systems assisted by computational methods. During my research career I have acquired extensive experience in the analysis of sequence data at the DNA and protein level. I’m trained both in NGS bioinformatic protocols (ChIP-seq, ATAC-seq, RNA-seq, genome assembly) and fine detail sequence analysis. Most importantly, I have gained proficiency in the use of the statistical models that are at the basis of the quantitative analysis of low and high throughput sequence data. Additionally, my experience as a lecturer and instructor has taught me that training researchers about the formal basis of bioinformatic methodologies is the key for a successful collaboration between wet and dry lab. Likewise, I have gained valuable skills by working within two international consortia (TARA Oceans project and TRANSNET): the ability to collaborate with multidisciplinary groups and to coordinate younger researchers.


Keywords
AlgorithmicsGenomicsSequence analysisTranscriptomicsGenome analysisGeneticsEvolutionInteractomics
Organisms

Projects (17)

Stéphane DESCORPS-DECLÈRE

Group : FUNGEN - Hub Core

Professional Experience Today – Institut Pasteur – HUB Team 2009 – today – Institut Pasteur – Bioinformatician 2006 – 2009 – CNRS, Orsay – Institut Génétique et Microbiologie – PostDoc 2002 – 2006 – INRIA, Grenoble – Ph.D 2000 – 2002 – INRIA, Action Helix, Grenoble – Expert engineer 1999 – 2000 – Infobiogen – Université EVE, Evry – Engineer Education 2002 – 2006 Thesis Paris VI, INRIA, Grenoble. 1999 – 2000 DESS Informatique Appliquée à la Biologie, UPMC 1997 – 1998 Maîtrise Biologie cellulaire et Physiologie animale, UPMC


Keywords
GenomicsSequence analysis
Organisms

Projects (6)

Olivia DOPPELT-AZEROUAL

Group : WINTER - Hub Core

ONGOING PROJECTS Galaxy administration/Maintenance (https://galaxy.web.pasteur.fr) Bioweb: Future directory of bioinformatics resources at the Institut Pasteur ELIXIR Registry SKILLS Galaxy: administration, API/Bioblend expertise Programming: Python, Javascript, Lua, R, Development tools: GIT, Subversion, Emacs Database: NoSQL (couchdb), MySQL, PostgreSQL Bioinformatics: Preprocessing NGS data, MED-SuMo, Protein surface comparison, Protein functional annotation. OTHER ACTIVITIES C3BI seminars and meetings management Involved in Galaxy France Working Group (IFB) FORMER PROJECTS MetaGenSense(https://metagensense.web.pasteur.fr) Disco-Bac (https://disco-bac.web.pasteur.fr)


Keywords
Data managementSequence analysisStructural bioinformaticsDatabaseProgram developmentScientific computingLIMS
Organisms

Projects (5)

Amine GHOZLANE

Group : PLATEFORM - Detached : Biomics

After a PhD in informatics on graph analysis (metabolic networks and sRNA-mRNA interaction graphs) at the LaBRI (Université de Bordeaux), I joined the DSIMB team (INTS) for a post-doc on structural modeling. Then, I performed a second post-doc at Metagenopolis – INRA Jouy-en-Josas, where I was initiated to the analysis of metagenomic data. I was recruited at the HUB in 2015, and since I pursue the development of methods dedicated to the treatment of metagenomic data by combining either the treatment of sequencing data, the statistics, the protein structural modeling and the graph analysis.


Keywords
AlgorithmicsClusteringGenome assemblyGenomicsMetabolomicsModelingNon coding RNASequence analysisStructural bioinformaticsTargeted metagenomicsDatabaseGenome analysisBiostatisticsProgram developmentScientific computingDatabases and ontologiesExploratory data analysisData and text miningIllumina HiSeqComparative metagenomicsRead mappingIllumina MiSeqSequence homology analysisGene predictionMultidimensional data analysisSequencingShotgun metagenomics
Organisms

Projects (18)

Julien GUGLIELMINI


After a PhD in Microbiology on bacterial toxin-antitoxin systems at the Free University of Brussels, I joined the Institut Pasteur for a 3 years postdoc in Eduardo Rocha’s lab. During this period, I performed comparative genomics and pylogenetic analysis on bacterial conjugation and type IV secretion systems. Then, I worked 2 years in Olivier Tenaillon’s team on the modelling and evolution of organismal complexity. I joined the HUB in 2015, and I am involved in phylogenetic and comparative genomics projects.


Keywords
GenomicsPhylogeneticsSequence analysisGenome analysisGeneticsEvolutionPopulation genetics
Organisms
ArchaeaBacteriaVirus
Projects (10)

Kenzo-Hugo HILLION

Group : WINTER - Hub Core

After a Master degree in Genetics at Magistère Européen de Génétique, Paris Diderot, I did a second Master in bioinformatics at University of Nantes where I focused my work on the study of mapping strategy for allele specific analysis at the bioinformatics platform of Institut Curie. I then joined Institut Pasteur to work on an ELIXIR project related to the bio.tools registry through the development of a dedicated tool and the participation of several workshops and hackathons. As an engineer of the bioinformatics and Biostatistics Hub, I am involved in several projects from Differential Analysis of RNA-seq data to Metagenomics. I am also in charge of the maintenance of the Galaxy Pasteur instance.


Keywords
ChIP-seqEpigenomicsGenomicsSequence analysisProgram developmentDatabases and ontologiesSofware development and engineeringGeneticsData integrationRead mappingWorkflow and pipeline developmentConfocal Microscopy
Organisms

Projects (4)

Bernd JAGLA

Group : PLATEFORM - Detached : Biomarker Discovery

Bernd Jagla received his PhD in bioinformatics (department of Biology, Chemistry, and Parmacy) from the Free University in Berlin, Germany in 1999. Before joining the Institut Pasteur, he worked for almost ten years in New York City, including as an associate research scientist in the Joint Centers for System Biology (Columbia University) and at the Columbia University Screening Center led by Dr J.E. Rothman. He joined the Institut Pasteur in 2009 to take charge of the bioinformatic needs at the Transcriptome et Epigenome platform, focusing on Next Generation Sequencing. As of 2016 he is member of the C3BI – HUB Team detached to the Human immunology center (CIH) and provides support for cytometry, next generation sequencing, and microarray data analysis. His areas of interest include the quality assurance and data analysis and visualization at the facility. He also has strong expertise in developing algorithms for function prediction from sequence data, image analysis, analysis of mass spectrometry data, workflow management systems. While at Pasteur he developed: KNIME extensions for Next Generation Sequencing (Link) Post Alignment Visualization and Characterization of High-Throughput Sequencing Experiments (Link) Post Alignment statistics of Illumina reads (Link)


Keywords
AlgorithmicsChIP-seqData managementData VisualizationImage analysisMachine learningSequence analysisDatabaseGenome analysisBiostatisticsProgram developmentScientific computingData and text miningIllumina HiSeqGraphics and Image ProcessingIllumina MiSeqHigh Throughput ScreeningFlow cytometry/cell sortingPac Bio
Organisms

Projects (1)

Varun KHANNA


2015 – . – Institut Pasteur, Paris, France – Unit : Bioinformatics and Biostatistics HUB 2012 – 2015 – Institut Pasteur, Paris, France – Unit : Molecular Genetics of Yeasts Supervisor : Prof. B. Dujon 2012 – Institut Pasteur, Paris, France – Unit : Integrated Mycobacterial Pathogenomics Supervisor: Dr. R. Brosch Education 2012– MSc. Bioinformatics – Université Paris Diderot (Paris VII)


Keywords
Genome assemblySequence analysisGenome analysisOrthology and paralogy analysisRead mappingSequence homology analysisDNA structure analysisGenome rearrangementsMotifs and patterns detection
Organisms
Saccharomyces cerevisiae
Projects (24)

Etienne KORNOBIS

Group : FUNGEN - Embedded : Epigenetic regulation

After a PhD in Biology in 2011 on population genetics and phylogeography on amazing little amphipods (Crangonyx, Crymostygius) at the University of Reykjavik (Iceland), I pursued my interest in Bioinformatics and Evolutionary Biology in various post-docs in Spain (MNCN Madrid, UB Barcelona). During this time, I investigated transcriptomic landscapes for various non-model species (groups Conus, Junco and Caecilians) using de novo assemblies and participated in the development of TRUFA, a web platform for de novo RNA-seq analysis. In July 2016, I integrated the Revive Consortium and the Epigenetic Regulation unit at Pasteur Institute, where my main focus were transcriptomic and epigenetic analyses on various thematics using short and long reads technologies, with a special interest in alternative splicing events detection. I joined the Bioinformatics and Biostatistics Hub in January 2018. My latest interests are long reads technologies, alternative splicing and achieving reproducibility in Bioinformatics using workflow managers, container technologies and literate programming.


Keywords
Data managementData VisualizationSequence analysisTranscriptomicsWeb developmentGenome analysisProgram developmentExploratory data analysisSofware development and engineeringGeneticsEvolutionRead mappingWorkflow and pipeline developmentPopulation geneticsMotifs and patterns detectionGrid and cloud computing
Organisms
HumanInsect or arthropodOther animalAnopheles gambiae (African malaria mosquito)Mouse
Projects (3)

Frédéric LEMOINE


After a Master degree in bioinformatics and biostatistics, I did a PhD in computer science / bioinformatics at University Paris-Sud (now in University Paris-Saclay), where I worked on integration and analysis of comparative genomics data. After a postdoc in Lausanne, Switzerland where I worked on small-RNA sequencing data, I joined GenoSplice where I was responsible for the development of bioinformatics projects related to next generation sequencing. I joined Institut Pasteur in Nov. 2015, to work in the Evolutionary Bioinformatics Unit and participate in the development of new tools and algorithms that are able to tackle efficiently the ever increasing amount of sequencing data.


Keywords
AlgorithmicsData managementPhylogeneticsSequence analysisDatabaseGenome analysisProgram developmentScientific computingDatabases and ontologiesSequencingWorkflow and pipeline development
Organisms

Projects (0)

    Christophe MALABAT

    Group : HEAD - Hub Core

    After a PhD in biochemistry of the rapeseed proteins, during which I developed my first automated scripts for handling data processing and analysis, I join Danone research facility center for developing multivariate models for the prediction of milk protein composition using infrared spectrometry.
    As I was already developing my own informatics tools, I decided to join the course of informatic for biology of the Institut Pasteur in 2007. At the end of the course I was recruited by the Institute and integrate the unit of “génétique des interactions macromoléculaires” of Alain Jacquier. Within this group, I learn to handle sequencing data and I developed processing and analysis tools using python and R. I also create a genome browser and database system for storing, retrieving and visualizing microarray data. After 8 years within the Alain Jacquier’s lab, I join the Hub of bioinformatics and biostatistics as co-head of the team.


    Keywords
    ClusteringData managementSequence analysisTranscriptomicsWeb developmentDatabaseGenome analysisProgram developmentScientific computingExploratory data analysisData and text miningIllumina HiSeqRead mappingLIMSIllumina MiSeqHigh Throughput ScreeningMultidimensional data analysisWorkflow and pipeline developmentRibosome profilingMotifs and patterns detection
    Organisms

    Projects (9)

    Damien MORNICO

    Group : FUNGEN - Hub Core

    Graduated in “Structural Genomics and Bioinformatics”, I mainly worked during almost 6 years at the Genoscope (CEA) in the LABGeM team, within the microbial annotation platform MicroScope. I specifically focused on functional annotation and microbial metabolic pathways prediction and reconstruction, through pipeline implementation, database modeling and web interface development. Broadly, interactions in the MicroScope platform allowed me to tackle the whole annotation process: from genome assembly and gene prediction to network reconstruction. I also performed several comparative genomics analyses. As a member of the “Hub team”, I now take part to various projects, linked to HTS data, on different subjects (lncRNAs and stem cells, HIV integration and DNA structure, Ribosomal protein genes and genome evolution, Natural Antisense Transcripts in compact genomes…).


    Keywords
    Data managementGenomicsSequence analysisWeb developmentDatabaseGenome analysisDatabases and ontologiesOrthology and paralogy analysisRead mappingSequence homology analysisGene prediction
    Organisms

    Projects (14)

    Natalia PIETROSEMOLI

    Group : FUNGEN - Hub Core

    Dr. Natalia Pietrosemoli is an Engineer with a M. Sc. in Modeling and Simulation of Complex Realities from the International Center for Theoretical Physics, ICTP and the International School of Advanced Studies, SISSA (Triest, Italy). During her M. Sc. internships she mostly worked in modeling, optimization, combinatorics and information theory applied to medical imaging. In 2012 she got a Ph. D in Computational Biology from the School of Bioengineering of Rice University (Houston, TX, US), where she specialized in computational structural biology and functional genomics. Her doctoral thesis “Protein functional features extracted with from primary sequences : a focus on disordered regions”, contributed to a better understanding of the functional and evolutionary role of intrinsic disorder in protein plasticity, complexity and adaptation to stress conditions. As part of her Ph. D., Natalia was a visiting scholar in two labs in Madrid: the Structural Computational Biology Group at the Spanish National Cancer Research Centre (CNIO), where she mainly worked in sequence analysis and the functional-structural relationships of proteins, and the Computational Systems Biology Group at the Spanish National Centre for Biotechnology (CNB-CSIC ), where she studied the functional implications of intrinsically disordered proteins at the genomic level for several organisms, collaborating with different experimental and theoretical groups. In 2013, she joined the Swiss Institute of Bioinformatics as a postdoctoral fellow in the Bioinformactics Core Facility. Her main project consisted in the molecular classification of a rare type of lymphoma, which involved the integration of transcriptomic, clinical and mutational data for the identification of molecular markers for classification, diagnosis and prognosis. This work was performed in collaboration with the Pathology Institute at the University Hospital of Lausanne (CHUV). In November of 2015 Natalia joined the Hub Team @ Pasteur C3BI as a Senior Bioinformatician. Natalia is especially interested in the integrative analysis of different omics data, both at large-scale and for small datasets, and loves collaborating in interdisciplinary environments and having feedback from her fellow experimental colleagues. Currently, she’s coordinating several projects performing functional and pathway analysis at the genomic level. By grouping genes, proteins and other biological molecules into the pathways they are involved in, the complexity of the analyses is significantly reduced, while the explanatory power increases with respect to having a list of differentially expressed genes or proteins.


    Keywords
    AlgorithmicsData managementGenomicsImage analysisMachine learningModelingProteomicsSequence analysisStructural bioinformaticsTranscriptomicsDatabaseGenome analysisBiostatisticsScientific computingDatabases and ontologiesApplication of mathematics in sciencesData and text miningGeneticsGraphics and Image ProcessingBiosensors and biomarkersClinical researchCell biology and developmental biologyInteractomicsBioimage analysis
    Organisms

    Projects (25)

    Najwa TAIB


    Najwa has been a postdoctoral fellow funded by the PTR project OM-Nega of the Institut Pasteur. Since January 2018 she has become the permanent bioinformatician of the group as part of the Hub team C3BI of the Institut Pasteur.


    Keywords
    GenomicsSequence analysisDatabaseGenome analysisEvolutionOrthology and paralogy analysis
    Organisms

    Projects (0)

      Hugo VARET

      Group : PLATEFORM - Detached : Biomics

      Hugo Varet is a biostatistician engineer from the Ensai (Ecole Nationale de la Statistique et de l’Analyse de l’Information) and has been recruited by the hub of the C3BI (Center of Bioinformatics, Biostatistics and Integrative Biology) to work at the Transcriptome & Epigenome Platform. He is in charge of the statistical analyses of the RNA-Seq data produced by the platform and develops R pipelines that help in this task. One of them is named SARTools and is available on GitHub: https://github.com/PF2-pasteur-fr/SARTools.


      Keywords
      ModelingSequence analysisStatistical inferenceTranscriptomicsBiostatisticsScientific computingApplication of mathematics in sciencesExploratory data analysisHigh Throughput ScreeningClinical research
      Organisms

      Projects (16)

      Related projects (32)

      Evolutionary relationships between giant viruses and eukaryotes

      The phylogenetic position and status of “giant viruses”, formerly called NucleoCytoplasmic Large DNA viruses (NCLDV) or putative order Megavirales, are controversial. Many preliminary phylogenetic analyses have been published, but their presentations are usually highly biased by the prejudice of the authors concerning the nature of giant viruses. Our own preliminary analyses suggest that giant viruses are indeed ancient (they predate the last universal eukaryotic ancestor) and have possibly provided important functions to emerging eukaryotic cells (e.g. DNA topoisomerase activities). The number of giant virus genomes has recently dramatically increased, opening new opportunity to study their position in the “universal tree of life” and their evolutionary relationships with eukaryotes. The aim of the project is to perform an exhaustive phylogenetic analysis of all giant virus proteins with eukaryotic (archaeal/bacterial) homologues to (i) test the monophyly of giant viruses, (ii) determine their contribution to early eukaryotic evolution, iii) determine if some giant virus proteins can be useful to root the eukaryotic tree. We need the help of a bioinformatics colleague with good expertise in building phylogenetic trees from large data sets using different methods of tree construction and robustness evaluation. This work will be complemented by the systematic search for significant indels (insertion/deletion) in the alignments obtained by two members of the BMGE team (Patrick Forterre and Morgan Gaia).



      Project status : In Progress

      Genome-wide replication lanscape of Candida glabrata

      Background: The opportunistic pathogen Candida glabrata is a member of the Saccharomycetaceae yeasts. Like its close relative Saccharomyces cerevisiae, it underwent a whole-genome duplication followed by an extensive loss of genes. Its genome contains a large number of very long tandem repeats, called Megasatellites. In order to determine the whole replication program of C. glabrata genome and its general chromosomal organization, we used deep-sequencing and Chromosome Conformation Capture (3C) experiments. Results: We identified 253 replication fork origins, genomewide. Centromeres, HML and HMR loci and most histone genes are replicated early, whereas natural chromosomal breakpoints are located in late replicating regions. In addition, 275 Autonomously Replicating Sequences (ARS) were identified during ARS-capture experiments, and their relative fitness was determined during growth competition. Analysis of ARSs allowed to identify a 17 bp consensus, similar to the S. cerevisiae ARS Consensus Sequence (ACS) but slightly more constrained. Megasatellites are not in close proximity to replication origins or termini. Using chromosome conformation capture, we also show that early origins tend to cluster whereas non-subtelomeric megasatellites do not cluster in the yeast nucleus. Conclusions: Despite a shorter cell cycle, the C. glabrata replication program shares unexpected striking similarities to S. cerevisiae, in spite of their large evolutionary distance and the presence of highly repetitive large tandem repeats in C. glabrata. No correlation could be found between the replication program and megasatellites, suggesting that their formation and propagation might not be directly caused by replication fork initiation or termination.



      Project status : Closed

      Identification of new cellular parameters involved in HIV-1 integration selectivity

      HIV-1 replication requires the integration of the viral genome into the cell genome. A viral-encoded enzyme, integrase (IN), performs this critical step of infection and is a promising target for anti-viral therapeutics. If the catalytic properties of INs are well characterized, the mechanisms responsible for their site selectivity are still under investigation. Several cellular proteins, such as the LEDFGF/p75 transcription co-activator, the RNA polymerase II machinery, nuclear pore proteins and specific modified histones have been proposed to be involved in IN selectivity at a genomic level but the underlying molecular mechanisms remain to be demonstrated. In addition, structural parameters of the target DNA helix (curvature, flexibility, topology) are proposed to regulate IN selectivity at a local level. Our aims are to study the role of these different parameters of IN selectivity, using both in vitro and in vivo approaches. In vitro, we will map integration sites on various target DNA substrates (naked DNA or chromatin, minicircles, plasmids with different topologies, transcribed templates) and will test the effect of purified proteins suspected to regulate IN selectivity. In vivo, integration sites will be mapped in cells depleted of these suspected regulators or in cells incubated with drugs targeting enzymes involved in transcription, DNA topology or histone modifications. Integration sites will be mapped using published or “home-made” protocols and the sites will be compared with DNA structural parameters, nucleosome positions, histone modifications or transcriptional parameters (published maps). Bio-informatics tools are crucial for these correlative and statistical analyses of integration sites. Our project relies on complementary in vivo, in vitro and in silico approaches. It should establish molecular and mechanistic rules of HIV-1 integration selectivity that could serve in the development of new antiviral strategies and of safer gene therapy vectors.



      Project status : Closed

      N/A



      Project status : In Progress

      A long-term mission for an assigned CIH-embedded bioinformatician to provide bioinformatic support to the CIH community

      The Center for Human Immunology (CIH) supports researchers involved in translational research projects by providing access to 16 different cutting edge technologies. Currently, the CIH hosts over 60 scientific projects coming from 8 departments of the Institut Pastuer and 5 external teams. In order to respond to the growing needs of these projects in the area of single cell analysis, the CIH has introduced a significant number of single-cell/single-molecule technologies over the past 2-3 years. These new technologies, such as the Personal Genome Machine (PGM) and Ion Proton sequencers, iSCAN microarray scanner, Nanostring technology for transcriptomics profiling and real-time PCR machine BioMark, give rise to large datasets with high dimensionality. Such trend, in terms of data complexity, is also true for flow cytometry technologies (currently reaching over 20 parameters per cell). The exploration of this data is generally beyond the scope of scientists involved in translational research projects. In order to maximize the research outcomes obtained from the analysis of these rich datasets, and to ensure that the full potential of our technologies can be served to the users of the CIH, we would require a proximity bioinformatics support. A CIH-embedded bioinformatician would: 1) design and implement standard analysis pipelines for each of the data-rich technologies of the CIH; 2) provide regular ‘bioinformatics clinics’ to allow scientists the possibility to customize standard pipelines to their specific needs; 3) run trainings on the ‘R software’ platform and other data analysis tools (such as Qlucore) of interest for the CIH users. The objective would be to empower the users to run exploratory analysis by themselves, and to teach good practices in terms of data management and data analysis.    



      Project status : In Progress

      Bio-informatics support for the LeiSHield project

      BioHub LeiSHield project This proposal summarizes the contribution of the BioHub to the LeiSHield action that may be carried out by a single BioHub Leishmania coordinator (Giovanni Bussotti). The coordinator will be implicated in the following actions: 1) Establish the link between LeiSHield members and the BioHub team for all questions regarding data analysis and interpretation. The coordinator will present to the BioHub the bio-informatics needs of the LeiSHield partners. Short (easy) tasks will be answered directly (following the BioHub open door strategy). For more involved tasks i twill be asked to deposit projects via the C3BI web site. 2) Coordinate the setup of an HTseq analysis pipeline, including quality control, read mapping, determination of CNV and SNPs, and data visualization using a combination of tools available at the BioHub, such as SyntView and Listeriomics. A link to Cedric Notredame will be established as scripts for Leishmania have been created there. 3) Oversee the submission of DNA from the different LeiSHield WPs to the IP HTseq facility, follow the progress, store the acquired data, and dispatch the datasets to the corresponding WP leaders. This will be coordinate with the Biomix infrastrcuture. 4) Apply the HTseq analysis pipeline (see point 1) on selected data sets for defined work packages, including WP4 (“Analysis of newly isolated anthroponotic L. donovani s.l. strains from Cyprus and correlation of genotypic profiles to tropism and drug resistance”), WP6 (“Population genetics of Brazilian L. infantum isolates from endemic areas presenting distinct transmission cycle”), WP7 (“Leishmania dovovani genome sequence diversity and disease tropism in the Sudan”), and WP9 (“Systems-wide analysis of Leishmania genomic and transcriptomic adaptation”). 5) Co-organize a course on HTseq data visualization (June 2016) with members of the BioHub team.



      Project status : In Progress

      Comparative genomic and phylogenetic analysis of Clostridium baratii strains



      Project status : Closed

      Regulation of HIV-1 integration selectivity by chromatin

      Integration of the viral reverse-transcribed genome into the genome of infected cells is an essential step of retroviral replication and is performed by a viral-encoded enzyme, named integrase (IN). In the case of HIV-1, IN is a new and efficient anti-viral target. The selectivity of this enzyme for its cellular genomic sites is also a major parameter of HIV replication and is regulated by several cellular parameters. One of them is chromatin, and different levels of this nucleoprotein complex are involved in the regulation of IN selectivity. Using in vitro integration assays, established by our team and collaborators, we have studied this regulation at two levels of chromatin architecture: large poly-nucleosome templates (Botbol et al., 2008; Lesbats et al., 2011; Benleulmi et al., 2015; Naughtin et al., 2015) or nucleosome-induced DNA curvature mimicked by DNA minicircles (Pasi et al., 2016). Our present project is to study IN selectivity into mononucleosomes (MN). These MNs will be used as target substrates of integration and the role of MN structure, histone modifications and IN cofactors will be studied. Results obtained in vitro, will be confronted to structural data obtained by molecular modeling and to integration sites observed in infected cells. This project will benefit from our expertise in integration in chromatin templates and a previous collaboration with the C3BI on the analysis of integration sites (Pasi, M., Mornico, D., S. Volant, S., et al., 2016). This project is funded by the ANRS.



      Project status : In Progress

      Utilize mouse models to study infection by HIV-1

      We previously showed that humanized immune system (HIS) mice generated in Balb/c Rag2-/-γc-/- SIRPNOD (BRGS) recipients are susceptible to HIV-1 infection (X4 and R5 isolates) and maintain circulating HIV-1 in the plasma, resulting in a dramatic depletion of human CD4+ T cells. We also characterized features of HIV physiopathology in this model. Human thymocyte subsets developing in the thymus of HIS mice appear phenotypically normal, but in the periphery the T cell repertoire is restricted compared with that of human peripheral blood T cells. This negatively impacts on the ability of HIS mice to generate antigen-specific human immune responses when mice are vaccinated with protein antigens or following infection with lymphotropic viruses such as HIV. One likely explanation for these functional deficiencies involves the fact that human T cells are selected intrathymically by mouse MHC molecules and that naïve T cells in peripheral lymphoid organs interact primarily with mouse DC (as human DC development in HIS mice is limited). As a first line of improvement, we recently generated a novel mouse model by crossing our BRGS mice with the HLA-A*02-HHD class I transgenic mice and the HLA-DRB1*15 class II transgenic mice, resulting in BRGS-A2DR2 mice. Following intra-hepatic injection of these mice with MHC-matched CD34+ stem cells we observed increased engraftment, with faster kinetics. Moreover BRGS-A2DR2 HIS mice have an increased T cell development leading to a more equilibrated B/T and CD4/CD8 phenotype. We showed that BRGS-A2DR2 HIS mice were able to sustain replication of HIV R5 virus as the BRGS hosts. Viremia was similar in a first phase and then lower in a second phase in BRGS-A2DR2 compared to BRGS HIS mice, which could be a consequence of a better quality of the immune response. However, the viremia reached a similar plateau in the last phase. We propose to study the impact of the immune res



      Project status : Awaiting Publication

      Bioinformatic analysis of the adenylate cyclase CyaA toxin

      The adenylate cyclase (CyaA) produced by B. pertussis, the causative agent of whooping cough, is one of the major virulence factors of this organism. CyaA plays an important role in the early stages of respiratory tract colonization by B. pertussis. This toxin uses an original intoxication mechanism: secreted by the virulent bacteria, it is able to invade eukaryotic target cells through a unique but poorly understood mechanism that involves a direct translocation of the catalytic domain across the plasma membrane. CyaA is a 1706-residue long protein organized in a modular fashion. The ATP-cyclizing, calmodulin-activated, catalytic domain (ACD) is located in the 400 amino-terminal residues. Once secreted by the bacteria, the toxin binds calcium in the extracellular milieu and refolds into a functional state. Then, CyaA translocates its catalytic domain directly across the plasma membrane from the extracellular medium to the host cell cytoplasm where, upon activation by endogenous calmodulin, it increases the concentration of cAMP to supraphysiological levels that ultimately leads to the cell death. Recently, we succeeded to refold CyaA in a stable and monomeric form that is fully folded and functional (at variance with all prior procedures in which the polypeptides were largely aggregated upon urea removal). Both calcium and molecular confinement are mandatory to produce the monomeric state and CyaA acylation also strongly contributes to the refolding process. We further show that the monomeric preparation displayed hemolytic and cytotoxic activities suggesting that the monomer is the genuine, physiologically active form of the toxin. Hence, despite recent advances in the understanding of CyaA, its mechanisms of cell intoxication process, in particular the membrane translocation step, remains poorly understood from a fundamental perspective. The description of the molecular events occurring prior to and during the translocation of the catalytic domain across the lipi



      Project status : Awaiting Publication