References of "Twizere, Jean-Claude"
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See detailDevelopment of mini scale-down platform based on the response of GFP microbial biosensors
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Poster (2012, May 18)

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor ... [more ▼]

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In our previous works, green fluorescent protein reporters have been used as biosensors of the heterogeneities generated in a two compartment scale-down reactor. As there is a huge variety of available whole cell biosensor to characterize the impact of such heterogeneities at the biological level, there is a need for high-throughput cultivation tools in order to investigate the usefulness of a given microbial biosensor among a library comprising several thousands of clones. This work is based on this statement and aims to investigate the potentialities of a mini scale-down platform. Four green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli: rpoS::gfp, uspA::gfp, csiE::gfp and yciG::gfp. The promoters rpoS and uspA are induced in response to a variety of stresses whereas the two other promoters, csiE and yciG, are supposed to be more specific in front of a glucose limitation. First, the response of these biosensors has been assessed in chemostat reactors. These kinds of experiments allow easier interpretation of responses of stress gene related to a glucose limitation since the extracellular conditions are constants and cells are renewed. Biosensors carrying the csiE and yciG promoters have exhibited an induction in function of the glucose limitation. Secondly, a scale-down platform has been tested with the same biosensors and two kinds of glucose addition mode. This scale-down platform involves high-throughput cultivation tools, i.e. in our case shake flask, equipped with non-invasive optical sensors for the monitoring of the dissolved oxygen profile in front of the glucose addition mode. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. The intermittent addition of glucose induces a slow down at the level of the GFP synthesis, suggesting that temporal accumulation of glucose inhibits the activity of the yciG and csiE promoters. In conclusion, the scale-down platform is able to reproduce the same kind of glucose fluctuations that encounters the cells in large-scale processes but not allows studying the impact of high-cell density culture on gene expression. [less ▲]

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See detailUse of microbial biosensors to detect substrate heterogeneities at the single cell level and assess microbial viability: Validation of a mini-bioreactor platform
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Conference (2012, March 15)

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor ... [more ▼]

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In this work, we have used these biosensors for the elaboration of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli, i.e. uspA::gfp, csiE::gfp and yciG::gfp. Our previous studies have shown that these kinds of promoters are induced in response of substrate limitation and exhibit a strong fluorescence attenuation when cultivated in heterogeneous bioreactors. This sensitivity to substrate limitation has been confirmed in the case of the csiE and yciG biosensors. A mini scale-down platform has been proposed as a high throughput tool to investigate rapidly the usefulness of a given microbial biosensor. This platform is composed of shake flask able to operate in fed-batch mode either by using the slow release or the intermittent feeding principle. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. Local heterogeneities have thus been reproduced at the level of these mini-bioreactors and these one have caused a decrease of GFP expression, as in conventional scale-down reactor. The presence of GFP in supernatants has also been noticed and seems to be correlated with the substrate limitation signal for the three cultivation systems considered in this work (i.e., chemostat, conventional and mini-bioreactors) and with the membrane permeability. [less ▲]

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See detailInteractomic map of the Ets factors family : Identification of unexpected functions in mRNA processing
Rambout, Xavier ULg; Simonis, Nicolas; Demoitié, Pauline et al

in Keystone symposium - Protein-RNA Interactions in Biology and Disease (C1) (2012, March 05)

The Ets factors are a family of 27 transcription factors characterized by their unique DNA-binding domain, the ETS domain. We aimed at building a protein-protein interaction (PPI) map (interactome) of the ... [more ▼]

The Ets factors are a family of 27 transcription factors characterized by their unique DNA-binding domain, the ETS domain. We aimed at building a protein-protein interaction (PPI) map (interactome) of the human Ets factors in order to better define their roles and regulations in normal and oncogenic processes. The Ets interactome was built on a high-throughput yeast-two hybrid (Y2H) approach, and a literature and database curation of confident interactions which led us to the identification of 602 PPIs and 369 different protein partners. Clusterization using the Network Analysis Tool box (NeAT) divided the ETS interactome into 39 functional sub-networks. Among these, we identified Cluster16 as highly connected to the Erg ETS subfamily. A gene ontology (GO) enrichment analysis revealed that Cluster16 was associated to various aspects of mRNA processing. We therefore hypothesized that Erg factors might have a role in post-transcriptional gene regulation. This would constitute a entirely new and undisclosed role for ETS factors, which are so far firmly established as transcription factors. In support of our hypothesis, we observed that ERG localized in p-bodies, cytoplasmic sites of mRNA decay. Interestingly, under various cellular stresses, a portion of ERG and its partners from Cluster16 localized in stress granules, cytoplasmic sites of mRNA silencing physically linked to p-bodies. Hence, we hypothesized that Erg proteins might be involved in cellular mRNAs degradation. To test this, we performed a MS2-based tethering assay and showed that the recruit-ment of Erg factors promoted degradation of a reporter mRNA, mainly via its N-ter domain. Very importantly, oncogenic TET-Erg fusions described in AML and Ewing’s sarcoma exhibited diminished ability to degrade target mRNAs, concomitantly with the loss of the N-ter domain of the corresponding Erg protein. This re-inforces the important role of Erg proteins in mRNA degradation in cancer. Our efforts are now concentrated on identifying the molecular determinants behind this new function of Erg proteins. [less ▲]

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See detailInteraction of HTLV-1 Tax with minichromosome maintenance proteins accelerates the replication timing program
Boxus, Mathieu ULg; Twizere, Jean-Claude ULg; Legros, Sébastien et al

in Blood (2012), 119

The Tax oncoprotein encoded by the Human T-cell leukemia virus type 1 (HTLV-1) plays a pivotal role in viral persistence and pathogenesis. HTLV-1 infected cells proliferate faster than normal lymphocytes ... [more ▼]

The Tax oncoprotein encoded by the Human T-cell leukemia virus type 1 (HTLV-1) plays a pivotal role in viral persistence and pathogenesis. HTLV-1 infected cells proliferate faster than normal lymphocytes, expand through mitotic division and accumulate genomic lesions. Here, we show that Tax associates with the minichromosome maintenance MCM2-7 helicase complex and localizes to origins of replication. Tax modulates the spatiotemporal program of origin activation and fires supplementary origins at the onset of S phase. Thereby, Tax increases the DNA replication rate, accelerates S phase progression but also generates a replicative stress characterized by the presence of genomic lesions. Mechanistically, Tax favors p300 recruitment and histone hyperacetylation at late replication domains advancing their replication timing in early S phase. [less ▲]

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See detailHost-pathogen interactome mapping for HTLV-1 and -2 retroviruses.
Simonis, Nicolas; Rual, Jean-Francois; Lemmens, Irma et al

in Retrovirology (2012), 9

BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1) and type 2 both target T lymphocytes, yet induce radically different phenotypic outcomes. HTLV-1 is a causative agent of Adult T-cell leukemia (ATL ... [more ▼]

BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1) and type 2 both target T lymphocytes, yet induce radically different phenotypic outcomes. HTLV-1 is a causative agent of Adult T-cell leukemia (ATL), whereas HTLV-2, highly similar to HTLV-1, causes no known overt disease. HTLV gene products are engaged in a dynamic struggle of activating and antagonistic interactions with host cells. Investigations focused on one or a few genes have identified several human factors interacting with HTLV viral proteins. Most of the available interaction data concern the highly investigated HTLV-1 Tax protein. Identifying shared and distinct host-pathogen protein interaction profiles for these two viruses would enlighten how they exploit distinctive or common strategies to subvert cellular pathways toward disease progression. RESULTS: We employ a scalable methodology for the systematic mapping and comparison of pathogen-host protein interactions that includes stringent yeast two-hybrid screening and systematic retest, as well as two independent validations through an additional protein interaction detection method and a functional transactivation assay. The final data set contained 166 interactions between 10 viral proteins and 122 human proteins. Among the 166 interactions identified, 87 and 79 involved HTLV-1 and HTLV-2 -encoded proteins, respectively. Targets for HTLV-1 and HTLV-2 proteins implicate a diverse set of cellular processes including the ubiquitin-proteasome system, the apoptosis, different cancer pathways and the Notch signaling pathway. CONCLUSIONS: This study constitutes a first pass, with homogeneous data, at comparative analysis of host targets for HTLV-1 and -2 retroviruses, complements currently existing data for formulation of systems biology models of retroviral induced diseases and presents new insights on biological pathways involved in retroviral infection. [less ▲]

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See detailProtein interactions of the transcription factor Hoxa1.
Lambert, Barbara; Vandeputte, Julie; Remacle, Sophie et al

in BMC Developmental Biology (2012), 12

BACKGROUND: Hox proteins are transcription factors involved in crucial processes during animal development. Their mode of action remains scantily documented. While other families of transcription factors ... [more ▼]

BACKGROUND: Hox proteins are transcription factors involved in crucial processes during animal development. Their mode of action remains scantily documented. While other families of transcription factors, like Smad or Stat, are known cell signaling transducers, such a function has never been squarely addressed for Hox proteins. RESULTS: To investigate the mode of action of mammalian Hoxa1, we characterized its interactome by a systematic yeast two-hybrid screening against ~12,200 ORF-derived polypeptides. Fifty nine interactors were identified of which 45 could be confirmed by affinity co-purification in animal cell lines. Many Hoxa1 interactors are proteins involved in cell-signaling transduction, cell adhesion and vesicular trafficking. Forty-one interactions were detectable in live cells by Bimolecular Fluorescence Complementation which revealed distinctive intracellular patterns for these interactions consistent with the selective recruitment of Hoxa1 by subgroups of partner proteins at vesicular, cytoplasmic or nuclear compartments. CONCLUSIONS: The characterization of the Hoxa1 interactome presented here suggests unexplored roles for Hox proteins in cell-to-cell communication and cell physiology. [less ▲]

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See detailInteraction network of antimicrobial peptides of Arabidopsis thaliana, based on hith-throughput yeast two-hybrid screening
Damon, Coralie ULg; Dmitrieva, Joelia Borisnova; Muhovski, Yordan et al

in Plant Physiology & Biochemistry (2012)

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See detailPotentiality of using microbial biosensors for the detection of substrate heterogeneities and the assessment of microbial viability in industrial bioreactors: a complete set of experiments in chemostat and scale-down reactors, and elaboration of a mini scale-down platform
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

in Communications in Agricultural and Applied Biological Sciences (2012), 77(1), 3-7

Substrate limitation responsive biosensors have been used in order to detect spatial substrate heterogeneities, , inside industrial bioreactors (whole-cell biosensor). Three green fluorescent protein (GFP ... [more ▼]

Substrate limitation responsive biosensors have been used in order to detect spatial substrate heterogeneities, , inside industrial bioreactors (whole-cell biosensor). Three green fluorescent protein (GFP) transcriptional reporters have been chosen in E.coli, i.e. uspA::gfp, csiE::gfp and yciG::gfp. The promoter uspA is induced in response to a variety of stresses whereas the two other promoters, csiE and yciG, are supposed to be more specific in front of a substrate limitation. The responsiveness of these biosensors has been assessed in chemostat reactor. Secondly, the same biosensors have been tested in well-mixed laboratory reactors and in scale-down reactors able to reproduce industrial conditions. Finally, a mini scale-down platform has been proposed as a high throughput tool to investigate rapidly the usefulness of a given microbial biosensor. Local heterogeneities in mini-bioreactor have caused a decrease of GFP expression, as in scale-down reactor. The presence of GFP in supernatants was noticed and this leakage seems to be correlated with the membrane permeability. [less ▲]

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See detailDisruption of PDZ protein-protein interactions inhibits Tax transformation and HTLV-1 infection capacities.
Twizere, Jean-Claude ULg; DEWULF, Jean-François; Blibek, Karim ULg et al

Poster (2011, June 06)

Human T-cell leukemia virus type I (HTLV-1) encodes a Tax oncoprotein that is critical for both viral replication and cellular transformation. HTLV-1 Tax possesses a PDZ domain binding motif (PBM) at its ... [more ▼]

Human T-cell leukemia virus type I (HTLV-1) encodes a Tax oncoprotein that is critical for both viral replication and cellular transformation. HTLV-1 Tax possesses a PDZ domain binding motif (PBM) at its C-terminus that is essential for its transforming activity in a Rat-1 model and for IL-2. Tax has been shown to interact with several PDZ domain containing proteins including PSD-95, Beta1-syntrophin, the precursor of interleukin-16, the mammalian homolog of the Drosophila discs large tumor suppressor protein Dlg, PDLIM2, Lin7, hTid1, Tip1, hScrib and MAGI3. In the 15th International Conference on Human Retrovirology: HTLV and Related Retroviruses, we will present a specificity map for the Tax/PDZ domain interactions generated using the human ORFeome 5.1. and we will focus on some of the new Tax/PDZ interactions. [less ▲]

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See detailEstablishment of an interactomic map of the Ets factors family: Towards a better understanding of their roles in oncogenic processes
Rambout, Xavier ULg; Simonis, Nicolas; Demoitié, Pauline et al

Poster (2011, April 29)

Ets transcription factors have been involved in several cancers such as leukemia, prostate cancer and Ewing’s sarcoma. They regulate the expression of genes controlling important biological processes such ... [more ▼]

Ets transcription factors have been involved in several cancers such as leukemia, prostate cancer and Ewing’s sarcoma. They regulate the expression of genes controlling important biological processes such as cellular proliferation, differentiation, apoptosis, metastasis, and transformation. This family of transcription factors is characterized by its highly conserved DNA-binding domain called the ETS domain and members are classified into subfamilies based on sequence homology criterion. We built a protein-protein interaction (PPI) network of the 27 Ets proteins and of their individual functional domains using a high-throughput yeast-two hybrid (Y2H) screening method. That Y2H network was expanded with confident literature-curated PPIs to obtain a comprehensive Ets interaction network. By considering connectivity between Ets interaction partners, we were able to segregate highly connected clusters of proteins from that network. Analysis of ontologies enrichment of those clusters enabled to confirm well-established roles and regulations of Ets factors, but also to suggest new ones. Biological validation of one precise cluster could be used as a rule of a thumb to globally confirm the bioinformatic analysis of our Ets PPI network and the potential physiological or pathological roles and regulation of Ets factors. [less ▲]

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See detailThe HTLV-1 Tax protein inhibits formation of stress granules by interacting with histone deacetylase 6.
Legros, S.; Boxus, Mathieu ULg; GATOT, Jean-Stéphane ULg et al

in Oncogene (2011)

Human T cell leukemia virus type-1 (HTLV-1) is the causative agent of a fatal adult T-cell leukemia. Through deregulation of multiple cellular signaling pathways the viral Tax protein has a pivotal role ... [more ▼]

Human T cell leukemia virus type-1 (HTLV-1) is the causative agent of a fatal adult T-cell leukemia. Through deregulation of multiple cellular signaling pathways the viral Tax protein has a pivotal role in T-cell transformation. In response to stressful stimuli, cells mount a cellular stress response to limit the damage that environmental forces inflict on DNA or proteins. During stress response, cells postpone the translation of most cellular mRNAs, which are gathered into cytoplasmic mRNA-silencing foci called stress granules (SGs) and allocate their available resources towards the production of dedicated stress-management proteins. Here we demonstrate that Tax controls the formation of SGs and interferes with the cellular stress response pathway. In agreement with previous reports, we observed that Tax relocates from the nucleus to the cytoplasm in response to environmental stress. We found that the presence of Tax in the cytoplasm of stressed cells prevents the formation of SGs and counteracts the shutoff of specific host proteins. Unexpectedly, nuclear localization of Tax promotes spontaneous aggregation of SGs, even in the absence of stress. Mutant analysis revealed that the SG inhibitory capacity of Tax is independent of its transcriptional abilities but relies on its interaction with histone deacetylase 6, a critical component of SGs. Importantly, the stress-protective effect of Tax was also observed in the context of HTLV-1 infected cells, which were shown to be less prone to form SGs and undergo apoptosis under arsenite exposure. These observations identify Tax as the first virally encoded inhibitory component of SGs and unravel a new strategy developed by HTLV-1 to deregulate normal cell processes. We postulate that inhibition of the stress response pathway by Tax would favor cell survival under stressful conditions and may have an important role in HTLV-1-induced cellular transformation.Oncogene advance online publication, 2 May 2011; doi:10.1038/onc.2011.120. [less ▲]

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See detailIdentification of a Brucella spp. secreted effector specifically interacting with human small GTPase Rab2.
de Barsy, Marie; Jamet, Alexandre; Filopon, Didier et al

in Cellular microbiology (2011), 13(7), 1044-58

Bacteria of the Brucella genus are facultative intracellular class III pathogens. These bacteria are able to control the intracellular trafficking of their vacuole, presumably by the use of yet unknown ... [more ▼]

Bacteria of the Brucella genus are facultative intracellular class III pathogens. These bacteria are able to control the intracellular trafficking of their vacuole, presumably by the use of yet unknown translocated effectors. To identify such effectors, we used a high-throughput yeast two-hybrid screen to identify interactions between putative human phagosomal proteins and predicted Brucella spp. proteins. We identified a specific interaction between the human small GTPase Rab2 and a Brucella spp. protein named RicA. This interaction was confirmed by GST-pull-down with the GDP-bound form of Rab2. A TEM-beta-lactamase-RicA fusion was translocated from Brucella abortus to RAW264.7 macrophages during infection. This translocation was not detectable in a strain deleted for the virB operon, coding for the type IV secretion system. However, RicA secretion in a bacteriological culture was still observed in a DeltavirB mutant. In HeLa cells, a DeltaricA mutant recruits less GTP-locked myc-Rab2 on its Brucella-containing vacuoles, compared with the wild-type strain. We observed altered kinetics of intracellular trafficking and faster proliferation of the B. abortusDeltaricA mutant in HeLa cells, compared with the wild-type control. Altogether, the data reported here suggest RicA as the first reported effector with a proposed function for B. abortus. [less ▲]

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See detailTARGETS FOR RETROVIRUS ASSOCIATED DISEASES
Twizere, Jean-Claude ULg

Patent (2010)

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See detailEstablishment of an interactomic map of the Ets factors family: Towards a better understanding of their roles in oncogenic processes
Rambout, Xavier ULg; Twizere, Jean-Claude ULg; Dequiedt, Franck ULg

in Inserm Workshop: Interactomics: at the crossroads of biology and bioinformatics (2010, March)

Ets transcription factors play key roles in several cancers such as leukemia, prostate cancer and Ewing’s sarcoma. They regulate the expression of genes controlling biological processes such as cellular ... [more ▼]

Ets transcription factors play key roles in several cancers such as leukemia, prostate cancer and Ewing’s sarcoma. They regulate the expression of genes controlling biological processes such as cellular proliferation, differentiation, apoptosis, metastasis, and transformation. This family is characterized by a highly conserved DNA-binding domain (ETS domain) and is classified into subfamilies according to sequence homology between the members. Using a high-throughput yeast two-hybrid (Y2H) method, we tested the interaction of the major splicing variants of the 28 human Ets factors and their functional domains of interest against the last available version of the human ORFeome (hORFeome v5.1). This screen has identified more than 200 new partners of Ets proteins. Further validation of these new interactions together with previously described interactions will enable a global evaluation of the regulation, and normal and cancerous roles of Ets factors. [less ▲]

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See detailNOD2 interactome
Lecat, Aurore ULg; Di Valentin, Emmanuel ULg; Fillet, Marianne ULg et al

Poster (2010, January 28)

Detailed reference viewed: 28 (10 ULg)