Publications
2013
Petrillo Jessica E, Venter Arno P, Short James R, Gopal Radhika, Deddouche Safia, Lamiable Olivier, Imler Jean-Luc, Schneemann Anette
Cytoplasmic granule formation and translational inhibition of nodaviral RNAs in the absence of the double-stranded RNA binding protein B2 Journal Article
In: Journal of Virology, vol. 87, no. 24, pp. 13409–13421, 2013, ISSN: 1098-5514.
Abstract | Links | BibTeX | Tags: Animals, Capsid Proteins, Cell Line, Cricetinae, Cytoplasmic Granules, Double-Stranded, imler, M3i, Nodaviridae, Protein Biosynthesis, RNA, RNA Virus Infections, RNA-Binding Proteins, Viral, Viral Proteins
@article{petrillo_cytoplasmic_2013,
title = {Cytoplasmic granule formation and translational inhibition of nodaviral RNAs in the absence of the double-stranded RNA binding protein B2},
author = {Jessica E Petrillo and Arno P Venter and James R Short and Radhika Gopal and Safia Deddouche and Olivier Lamiable and Jean-Luc Imler and Anette Schneemann},
doi = {10.1128/JVI.02362-13},
issn = {1098-5514},
year = {2013},
date = {2013-12-01},
journal = {Journal of Virology},
volume = {87},
number = {24},
pages = {13409--13421},
abstract = {Flock House virus (FHV) is a positive-sense RNA insect virus with a bipartite genome. RNA1 encodes the RNA-dependent RNA polymerase, and RNA2 encodes the capsid protein. A third protein, B2, is translated from a subgenomic RNA3 derived from the 3' end of RNA1. B2 is a double-stranded RNA (dsRNA) binding protein that inhibits RNA silencing, a major antiviral defense pathway in insects. FHV is conveniently propagated in Drosophila melanogaster cells but can also be grown in mammalian cells. It was previously reported that B2 is dispensable for FHV RNA replication in BHK21 cells; therefore, we chose this cell line to generate a viral mutant that lacked the ability to produce B2. Consistent with published results, we found that RNA replication was indeed vigorous but the yield of progeny virus was negligible. Closer inspection revealed that infected cells contained very small amounts of coat protein despite an abundance of RNA2. B2 mutants that had reduced affinity for dsRNA produced analogous results, suggesting that the dsRNA binding capacity of B2 somehow played a role in coat protein synthesis. Using fluorescence in situ hybridization of FHV RNAs, we discovered that RNA2 is recruited into large cytoplasmic granules in the absence of B2, whereas the distribution of RNA1 remains largely unaffected. We conclude that B2, by binding to double-stranded regions in progeny RNA2, prevents recruitment of RNA2 into cellular structures, where it is translationally silenced. This represents a novel function of B2 that further contributes to successful completion of the nodaviral life cycle.},
keywords = {Animals, Capsid Proteins, Cell Line, Cricetinae, Cytoplasmic Granules, Double-Stranded, imler, M3i, Nodaviridae, Protein Biosynthesis, RNA, RNA Virus Infections, RNA-Binding Proteins, Viral, Viral Proteins},
pubstate = {published},
tppubtype = {article}
}
2009
Berry Bassam, Deddouche Safia, Kirschner Doris, Imler Jean-Luc, Antoniewski Christophe
Viral suppressors of RNA silencing hinder exogenous and endogenous small RNA pathways in Drosophila Journal Article
In: PloS One, vol. 4, no. 6, pp. e5866, 2009, ISSN: 1932-6203.
Abstract | Links | BibTeX | Tags: Animals, Antiviral Agents, Crosses, Double-Stranded, Gene Silencing, Genetic, Genetically Modified, Heterozygote, imler, Invertebrate, M3i, Photoreceptor Cells, Reverse Transcriptase Polymerase Chain Reaction, RNA, RNA Interference, Transgenes
@article{berry_viral_2009,
title = {Viral suppressors of RNA silencing hinder exogenous and endogenous small RNA pathways in Drosophila},
author = {Bassam Berry and Safia Deddouche and Doris Kirschner and Jean-Luc Imler and Christophe Antoniewski},
doi = {10.1371/journal.pone.0005866},
issn = {1932-6203},
year = {2009},
date = {2009-01-01},
journal = {PloS One},
volume = {4},
number = {6},
pages = {e5866},
abstract = {BACKGROUND: In plants and insects, RNA interference (RNAi) is the main responder against viruses and shapes the basis of antiviral immunity. Viruses counter this defense by expressing viral suppressors of RNAi (VSRs). While VSRs in Drosophila melanogaster were shown to inhibit RNAi through different modes of action, whether they act on other silencing pathways remained unexplored. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that expression of various plant and insect VSRs in transgenic flies does not perturb the Drosophila microRNA (miRNA) pathway; but in contrast, inhibits antiviral RNAi and the RNA silencing response triggered by inverted repeat transcripts, and injection of dsRNA or siRNA. Strikingly, these VSRs also suppressed transposon silencing by endogenous siRNAs (endo-siRNAs). CONCLUSIONS/SIGNIFICANCE: Our findings identify VSRs as tools to unravel small RNA pathways in insects and suggest a cosuppression of antiviral RNAi and endo-siRNA silencing by viruses during fly infections.},
keywords = {Animals, Antiviral Agents, Crosses, Double-Stranded, Gene Silencing, Genetic, Genetically Modified, Heterozygote, imler, Invertebrate, M3i, Photoreceptor Cells, Reverse Transcriptase Polymerase Chain Reaction, RNA, RNA Interference, Transgenes},
pubstate = {published},
tppubtype = {article}
}
2006
Shiao Shin-Hong, Whitten Miranda M A, Zachary Daniel, Hoffmann Jules A, Levashina Elena A
Fz2 and cdc42 mediate melanization and actin polymerization but are dispensable for Plasmodium killing in the mosquito midgut Journal Article
In: PLoS Pathog., vol. 2, no. 12, pp. e133, 2006, ISSN: 1553-7374.
Abstract | Links | BibTeX | Tags: Actins, Animals, Anopheles, Carrier Proteins, cdc42 GTP-Binding Protein, Double-Stranded, Electron, Frizzled Receptors, Gastrointestinal Tract, hoffmann, Host-Parasite Interactions, Immunity, Innate, Insect Vectors, Intestinal Mucosa, M3i, Melanins, Microarray Analysis, Microscopy, Plasmodium berghei, Polymers, Protozoan, RNA, scanning, telomerase
@article{shiao_fz2_2006,
title = {Fz2 and cdc42 mediate melanization and actin polymerization but are dispensable for Plasmodium killing in the mosquito midgut},
author = {Shin-Hong Shiao and Miranda M A Whitten and Daniel Zachary and Jules A Hoffmann and Elena A Levashina},
doi = {10.1371/journal.ppat.0020133},
issn = {1553-7374},
year = {2006},
date = {2006-12-01},
journal = {PLoS Pathog.},
volume = {2},
number = {12},
pages = {e133},
abstract = {The midgut epithelium of the mosquito malaria vector Anopheles is a hostile environment for Plasmodium, with most parasites succumbing to host defenses. This study addresses morphological and ultrastructural features associated with Plasmodium berghei ookinete invasion in Anopheles gambiae midguts to define the sites and possible mechanisms of parasite killing. We show by transmission electron microscopy and immunofluorescence that the majority of ookinetes are killed in the extracellular space. Dead or dying ookinetes are surrounded by a polymerized actin zone formed within the basal cytoplasm of adjacent host epithelial cells. In refractory strain mosquitoes, we found that formation of this zone is strongly linked to prophenoloxidase activation leading to melanization. Furthermore, we identify two factors controlling both phenomena: the transmembrane receptor frizzled-2 and the guanosine triphosphate-binding protein cell division cycle 42. However, the disruption of actin polymerization and melanization by double-stranded RNA inhibition did not affect ookinete survival. Our results separate the mechanisms of parasite killing from subsequent reactions manifested by actin polymerization and prophenoloxidase activation in the A. gambiae-P. berghei model. These latter processes are reminiscent of wound healing in other organisms, and we propose that they represent a form of wound-healing response directed towards a moribund ookinete, which is perceived as damaged tissue.},
keywords = {Actins, Animals, Anopheles, Carrier Proteins, cdc42 GTP-Binding Protein, Double-Stranded, Electron, Frizzled Receptors, Gastrointestinal Tract, hoffmann, Host-Parasite Interactions, Immunity, Innate, Insect Vectors, Intestinal Mucosa, M3i, Melanins, Microarray Analysis, Microscopy, Plasmodium berghei, Polymers, Protozoan, RNA, scanning, telomerase},
pubstate = {published},
tppubtype = {article}
}
Flacher Vincent, Bouschbacher Marielle, Verronèse Estelle, Massacrier Catherine, Sisirak Vanja, Berthier-Vergnes Odile, de Saint-Vis Blandine, Caux Christophe, Dezutter-Dambuyant Colette, Lebecque Serge, Valladeau Jenny
Human Langerhans cells express a specific TLR profile and differentially respond to viruses and Gram-positive bacteria Journal Article
In: Journal of Immunology (Baltimore, Md.: 1950), vol. 177, no. 11, pp. 7959–7967, 2006, ISSN: 0022-1767.
Abstract | Links | BibTeX | Tags: bacteria, Double-Stranded, Gram-Positive Bacteria, Human, Humans, Interleukin-6, Interleukin-8, Langerhans Cells, Reverse Transcriptase Polymerase Chain Reaction, RNA, Skin, Team-Mueller, TLR4, TLR7, Toll-Like Receptors, Tumor Necrosis Factor-alpha, viruses
@article{flacher_human_2006,
title = {Human Langerhans cells express a specific TLR profile and differentially respond to viruses and Gram-positive bacteria},
author = {Vincent Flacher and Marielle Bouschbacher and Estelle Verronèse and Catherine Massacrier and Vanja Sisirak and Odile Berthier-Vergnes and Blandine de Saint-Vis and Christophe Caux and Colette Dezutter-Dambuyant and Serge Lebecque and Jenny Valladeau},
doi = {10.4049/jimmunol.177.11.7959},
issn = {0022-1767},
year = {2006},
date = {2006-12-01},
journal = {Journal of Immunology (Baltimore, Md.: 1950)},
volume = {177},
number = {11},
pages = {7959--7967},
abstract = {Dendritic cells (DC) are APCs essential for the development of primary immune responses. In pluristratified epithelia, Langerhans cells (LC) are a critical subset of DC which take up Ags and migrate toward lymph nodes upon inflammatory stimuli. TLR allow detection of pathogen-associated molecular patterns (PAMP) by different DC subsets. The repertoire of TLR expressed by human LC is uncharacterized and their ability to directly respond to PAMP has not been systematically investigated. In this study, we show for the first time that freshly purified LC from human skin express mRNA encoding TLR1, TLR2, TLR3, TLR5, TLR6 and TLR10. In addition, keratinocytes ex vivo display TLR1-5, TLR7, and TLR10. Accordingly, highly enriched immature LC efficiently respond to TLR2 agonists peptidoglycan and lipoteichoic acid from Gram-positive bacteria, and to dsRNA which engages TLR3. In contrast, LC do not directly sense TLR7/8 ligands and LPS from Gram-negative bacteria, which signals through TLR4. TLR engagement also results in cytokine production, with marked differences depending on the PAMP detected. TLR2 and TLR3 ligands increase IL-6 and IL-8 production, while dsRNA alone stimulates TNF-alpha release. Strikingly, only peptidoglycan triggers IL-10 secretion, thereby suggesting a specific function in tolerance to commensal Gram-positive bacteria. However, LC do not produce IL-12p70 or type I IFNs. In conclusion, human LC are equipped with TLR that enable direct detection of PAMP from viruses and Gram-positive bacteria, subsequent phenotypic maturation, and differential cytokine production. This implies a significant role for LC in the control of skin immune responses.},
keywords = {bacteria, Double-Stranded, Gram-Positive Bacteria, Human, Humans, Interleukin-6, Interleukin-8, Langerhans Cells, Reverse Transcriptase Polymerase Chain Reaction, RNA, Skin, Team-Mueller, TLR4, TLR7, Toll-Like Receptors, Tumor Necrosis Factor-alpha, viruses},
pubstate = {published},
tppubtype = {article}
}
2003
Goto Akira, Blandin Stéphanie A, Royet Julien, Reichhart Jean-Marc, Levashina Elena A
Silencing of Toll pathway components by direct injection of double-stranded RNA into Drosophila adult flies Journal Article
In: Nucleic Acids Res., vol. 31, no. 22, pp. 6619–6623, 2003, ISSN: 1362-4962.
Abstract | BibTeX | Tags: Animals, blandin, Cell Surface, Double-Stranded, Epistasis, Female, Genetic, Green Fluorescent Proteins, Homeodomain Proteins, Luminescent Proteins, M3i, Phenotype, Receptors, reichhart, RNA, RNA Interference, Serpins, Signal Transduction, Time Factors, Toll-Like Receptors, Transcription Factors
@article{goto_silencing_2003,
title = {Silencing of Toll pathway components by direct injection of double-stranded RNA into Drosophila adult flies},
author = {Akira Goto and Stéphanie A Blandin and Julien Royet and Jean-Marc Reichhart and Elena A Levashina},
issn = {1362-4962},
year = {2003},
date = {2003-11-01},
journal = {Nucleic Acids Res.},
volume = {31},
number = {22},
pages = {6619--6623},
abstract = {Double-stranded RNA (dsRNA) gene interference is an efficient method to silence gene expression in a sequence-specific manner. Here we show that the direct injection of dsRNA can be used in adult Drosophila flies to disrupt function of endogenous genes in vivo. As a proof of principle, we have used this method to silence components of a major signaling cascade, the Toll pathway, which controls fruit fly resistance to fungal and Gram-positive bacterial infections. We demonstrate that the knockout is efficient only if dsRNA is injected in 4- or more day-old flies and that it lasts for at least 1 week. Furthermore, we report dsRNA-based epistatic gene analysis via injection of a mixture of two dsRNAs and propose that injection of dsRNA represents a powerful method for rapid functional analysis of genes in Drosophila melanogaster adults, particularly of those whose mutations are lethal during development.},
keywords = {Animals, blandin, Cell Surface, Double-Stranded, Epistasis, Female, Genetic, Green Fluorescent Proteins, Homeodomain Proteins, Luminescent Proteins, M3i, Phenotype, Receptors, reichhart, RNA, RNA Interference, Serpins, Signal Transduction, Time Factors, Toll-Like Receptors, Transcription Factors},
pubstate = {published},
tppubtype = {article}
}
2001
Levashina Elena A, Moita L F, Blandin Stéphanie A, Vriend G, Lagueux Marie, Kafatos F C
Conserved role of a complement-like protein in phagocytosis revealed by dsRNA knockout in cultured cells of the mosquito, Anopheles gambiae Journal Article
In: Cell, vol. 104, no. 5, pp. 709–718, 2001, ISSN: 0092-8674.
Abstract | BibTeX | Tags: alpha-Macroglobulins, Animals, Anopheles, blandin, Cells, Cloning, Complement C3, Cultured, DNA Fragmentation, Double-Stranded, Female, Genetic, Gram-Negative Bacteria, Hemocytes, Insect Proteins, M3i, Molecular, Nucleic Acid Denaturation, Phagocytosis, Protein Structure, RNA, Tertiary, Transcription
@article{levashina_conserved_2001,
title = {Conserved role of a complement-like protein in phagocytosis revealed by dsRNA knockout in cultured cells of the mosquito, Anopheles gambiae},
author = {Elena A Levashina and L F Moita and Stéphanie A Blandin and G Vriend and Marie Lagueux and F C Kafatos},
issn = {0092-8674},
year = {2001},
date = {2001-01-01},
journal = {Cell},
volume = {104},
number = {5},
pages = {709--718},
abstract = {We characterize a novel hemocyte-specific acute phase glycoprotein from the malaria vector, Anopheles gambiae. It shows substantial structural and functional similarities, including the highly conserved thioester motif, to both a central component of mammalian complement system, factor C3, and to a pan-protease inhibitor, alpha2-macroglobulin. Most importantly, this protein serves as a complement-like opsonin and promotes phagocytosis of some Gram-negative bacteria in a mosquito hemocyte-like cell line. Chemical inactivation by methylamine and depletion by double-stranded RNA knockout demonstrate that this function is dependent on the internal thioester bond. This evidence of a complement-like function in a protostome animal adds substantially to the accumulating evidence of a common ancestry of immune defenses in insects and vertebrates.},
keywords = {alpha-Macroglobulins, Animals, Anopheles, blandin, Cells, Cloning, Complement C3, Cultured, DNA Fragmentation, Double-Stranded, Female, Genetic, Gram-Negative Bacteria, Hemocytes, Insect Proteins, M3i, Molecular, Nucleic Acid Denaturation, Phagocytosis, Protein Structure, RNA, Tertiary, Transcription},
pubstate = {published},
tppubtype = {article}
}