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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}
}
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.
2007
Croker Ben, Crozat Karine, Berger Michael, Xia Yu, Sovath Sosathya, Schaffer Lana, Eleftherianos Ioannis, Imler Jean-Luc, Beutler Bruce
ATP-sensitive potassium channels mediate survival during infection in mammals and insects Journal Article
In: Nature Genetics, vol. 39, no. 12, pp. 1453–1460, 2007, ISSN: 1546-1718.
Abstract | Links | BibTeX | Tags: Animals, ATP-Binding Cassette Transporters, Cloning, Coronary Vessels, Crosses, Ethylnitrosourea, Genetic, Homozygote, imler, infection, Inwardly Rectifying, KATP Channels, Lipopolysaccharides, M3i, Mice, Molecular, Mutagenesis, Potassium Channels, Sulfonylurea Receptors
@article{croker_atp-sensitive_2007,
title = {ATP-sensitive potassium channels mediate survival during infection in mammals and insects},
author = {Ben Croker and Karine Crozat and Michael Berger and Yu Xia and Sosathya Sovath and Lana Schaffer and Ioannis Eleftherianos and Jean-Luc Imler and Bruce Beutler},
doi = {10.1038/ng.2007.25},
issn = {1546-1718},
year = {2007},
date = {2007-01-01},
journal = {Nature Genetics},
volume = {39},
number = {12},
pages = {1453--1460},
abstract = {Specific homeostatic mechanisms confer stability in innate immune responses, preventing injury or death from infection. Here we identify, from a screen of N-ethyl-N-nitrosourea-mutagenized mice, a mutation causing both profound susceptibility to infection by mouse cytomegalovirus and approximately 20,000-fold sensitization to lipopolysaccharide (LPS), poly(I.C) and immunostimulatory (CpG) DNA. The LPS hypersensitivity phenotype is not suppressed by mutations in Myd88, Trif, Tnf, Tnfrsf1a, Ifnb, Ifng or Stat1, genes contributing to LPS responses, and results from an abnormality extrinsic to hematopoietic cells. The phenotype is due to a null allele of Kcnj8, encoding Kir6.1, a protein that combines with SUR2 to form an ATP-sensitive potassium channel (K(ATP)) expressed in coronary artery smooth muscle and endothelial cells. In Drosophila melanogaster, suppression of dSUR by RNA interference similarly causes hypersensitivity to infection by flock house virus. Thus, K(ATP) evolved to serve a homeostatic function during infection, and in mammals it prevents coronary artery vasoconstriction induced by cytokines dependent on TLR and/or MDA5 immunoreceptors.},
keywords = {Animals, ATP-Binding Cassette Transporters, Cloning, Coronary Vessels, Crosses, Ethylnitrosourea, Genetic, Homozygote, imler, infection, Inwardly Rectifying, KATP Channels, Lipopolysaccharides, M3i, Mice, Molecular, Mutagenesis, Potassium Channels, Sulfonylurea Receptors},
pubstate = {published},
tppubtype = {article}
}
Specific homeostatic mechanisms confer stability in innate immune responses, preventing injury or death from infection. Here we identify, from a screen of N-ethyl-N-nitrosourea-mutagenized mice, a mutation causing both profound susceptibility to infection by mouse cytomegalovirus and approximately 20,000-fold sensitization to lipopolysaccharide (LPS), poly(I.C) and immunostimulatory (CpG) DNA. The LPS hypersensitivity phenotype is not suppressed by mutations in Myd88, Trif, Tnf, Tnfrsf1a, Ifnb, Ifng or Stat1, genes contributing to LPS responses, and results from an abnormality extrinsic to hematopoietic cells. The phenotype is due to a null allele of Kcnj8, encoding Kir6.1, a protein that combines with SUR2 to form an ATP-sensitive potassium channel (K(ATP)) expressed in coronary artery smooth muscle and endothelial cells. In Drosophila melanogaster, suppression of dSUR by RNA interference similarly causes hypersensitivity to infection by flock house virus. Thus, K(ATP) evolved to serve a homeostatic function during infection, and in mammals it prevents coronary artery vasoconstriction induced by cytokines dependent on TLR and/or MDA5 immunoreceptors.
2003
Ligoxygakis Petros, Roth Siegfried, Reichhart Jean-Marc
A serpin regulates dorsal-ventral axis formation in the Drosophila embryo Journal Article
In: Curr. Biol., vol. 13, no. 23, pp. 2097–2102, 2003, ISSN: 0960-9822.
Abstract | BibTeX | Tags: Animals, Body Patterning, Cell Surface, Crosses, Female, Genetic, Immunohistochemistry, M3i, Microinjections, Receptors, reichhart, Serine Proteinase Inhibitors, Serpins, Signal Transduction, Toll-Like Receptors
@article{ligoxygakis_serpin_2003,
title = {A serpin regulates dorsal-ventral axis formation in the Drosophila embryo},
author = {Petros Ligoxygakis and Siegfried Roth and Jean-Marc Reichhart},
issn = {0960-9822},
year = {2003},
date = {2003-12-01},
journal = {Curr. Biol.},
volume = {13},
number = {23},
pages = {2097--2102},
abstract = {Extracellular serine protease cascades have evolved in vertebrates and invertebrates to mediate rapid, local reactions to physiological or pathological cues. The serine protease cascade that triggers the Toll signaling pathway in Drosophila embryogenesis shares several organizational characteristics with those involved in mammalian complement and blood clotting. One of the hallmarks of such cascades is their regulation by serine protease inhibitors (serpins). Serpins act as suicide substrates and are cleaved by their target protease, forming an essentially irreversible 1:1 complex. The biological importance of serpins is highlighted by serpin dysfunction diseases, such as thrombosis caused by a deficiency in antithrombin. Here, we describe how a serpin controls the serine protease cascade, leading to Toll pathway activation. Female flies deficient in Serpin-27A produce embryos that lack dorsal-ventral polarity and show uniform high levels of Toll signaling. Since this serpin has been recently shown to restrain an immune reaction in the blood of Drosophila, it demonstrates that proteolysis can be regulated by the same serpin in different biological contexts.},
keywords = {Animals, Body Patterning, Cell Surface, Crosses, Female, Genetic, Immunohistochemistry, M3i, Microinjections, Receptors, reichhart, Serine Proteinase Inhibitors, Serpins, Signal Transduction, Toll-Like Receptors},
pubstate = {published},
tppubtype = {article}
}
Extracellular serine protease cascades have evolved in vertebrates and invertebrates to mediate rapid, local reactions to physiological or pathological cues. The serine protease cascade that triggers the Toll signaling pathway in Drosophila embryogenesis shares several organizational characteristics with those involved in mammalian complement and blood clotting. One of the hallmarks of such cascades is their regulation by serine protease inhibitors (serpins). Serpins act as suicide substrates and are cleaved by their target protease, forming an essentially irreversible 1:1 complex. The biological importance of serpins is highlighted by serpin dysfunction diseases, such as thrombosis caused by a deficiency in antithrombin. Here, we describe how a serpin controls the serine protease cascade, leading to Toll pathway activation. Female flies deficient in Serpin-27A produce embryos that lack dorsal-ventral polarity and show uniform high levels of Toll signaling. Since this serpin has been recently shown to restrain an immune reaction in the blood of Drosophila, it demonstrates that proteolysis can be regulated by the same serpin in different biological contexts.
2001
Monneaux F, Dumortier H, Steiner G, Briand J P, Muller S
In: International Immunology, vol. 13, no. 9, pp. 1155–1163, 2001, ISSN: 0953-8178.
Abstract | Links | BibTeX | Tags: Animals, Antibody Specificity, B-Lymphocytes, Crosses, Dumortier, fas Receptor, Female, Genetic, Heterogeneous-Nuclear Ribonucleoprotein Group A-B, Heterogeneous-Nuclear Ribonucleoproteins, Histocompatibility Antigens Class II, I2CT, Immunoglobulin G, Inbred MRL lpr, Inbred NZB, Lupus Erythematosus, Mice, Monneaux, Peptide Fragments, Ribonucleoprotein, Ribonucleoproteins, Small Nuclear, Species Specificity, Spliceosomes, Systemic, T-Lymphocytes, Team-Dumortier, U1 Small Nuclear
@article{monneaux_murine_2001,
title = {Murine models of systemic lupus erythematosus: B and Ŧ cell responses to spliceosomal ribonucleoproteins in MRL/Fas(lpr) and (NZB x NZW)F(1) lupus mice},
author = {F Monneaux and H Dumortier and G Steiner and J P Briand and S Muller},
doi = {10.1093/intimm/13.9.1155},
issn = {0953-8178},
year = {2001},
date = {2001-01-01},
journal = {International Immunology},
volume = {13},
number = {9},
pages = {1155--1163},
abstract = {(NZB x NZW)F(1) and MRL/Fas(lpr) lupus mice present a similar phenotype with a spectrum of autoantibodies associated with very severe nephritis. It is thought, however, that in contrast to other lupus-prone mice such as MRL/Fas(lpr) mice, (NZB x NZW)F(1) mice do not generate autoantibodies to ribonucleoproteins (RNP) Sm/RNP. In this study, we demonstrate that contrary to previous reports, the autoimmune response directed against Sm/RNP antigens also occurs in NZB x NZW mice. CD4(+) T cells from unprimed 10-week-old NZB x NZW mice proliferate and secrete IL-2 in response to peptide 131-151 of the U1-70K protein, which is known to contain a T(h) epitope recognized by CD4(+) T cells from MRL/Fas(lpr) mice. Peptide 131-151, which was found to bind I-A(k) and I-E(k) class II MHC molecules, also bound both I-A(d) and I-E(d) molecules. This result led us to also re-evaluate longitudinally the anti-Sm/RNP antibody response in NZB x NZW mice. We found that 25-week-old mice do produce antibodies reacting with several small nuclear and heterogeneous nuclear (hn) RNP proteins, such as SmD1, U1-70K and hnRNP A2/B1 proteins. The fine specificity of these antibodies was studied with overlapping synthetic peptides. The same antigenically positive and negative peptides were characterized in MRL/Fas(lpr) and NZB x NZW mice in the three proteins. This new finding can help to understand the mechanisms involved in the development of the anti-Sm/RNP antibody response and, particularly, the role played by non-MHC genes in this autoimmune response.},
keywords = {Animals, Antibody Specificity, B-Lymphocytes, Crosses, Dumortier, fas Receptor, Female, Genetic, Heterogeneous-Nuclear Ribonucleoprotein Group A-B, Heterogeneous-Nuclear Ribonucleoproteins, Histocompatibility Antigens Class II, I2CT, Immunoglobulin G, Inbred MRL lpr, Inbred NZB, Lupus Erythematosus, Mice, Monneaux, Peptide Fragments, Ribonucleoprotein, Ribonucleoproteins, Small Nuclear, Species Specificity, Spliceosomes, Systemic, T-Lymphocytes, Team-Dumortier, U1 Small Nuclear},
pubstate = {published},
tppubtype = {article}
}
(NZB x NZW)F(1) and MRL/Fas(lpr) lupus mice present a similar phenotype with a spectrum of autoantibodies associated with very severe nephritis. It is thought, however, that in contrast to other lupus-prone mice such as MRL/Fas(lpr) mice, (NZB x NZW)F(1) mice do not generate autoantibodies to ribonucleoproteins (RNP) Sm/RNP. In this study, we demonstrate that contrary to previous reports, the autoimmune response directed against Sm/RNP antigens also occurs in NZB x NZW mice. CD4(+) T cells from unprimed 10-week-old NZB x NZW mice proliferate and secrete IL-2 in response to peptide 131-151 of the U1-70K protein, which is known to contain a T(h) epitope recognized by CD4(+) T cells from MRL/Fas(lpr) mice. Peptide 131-151, which was found to bind I-A(k) and I-E(k) class II MHC molecules, also bound both I-A(d) and I-E(d) molecules. This result led us to also re-evaluate longitudinally the anti-Sm/RNP antibody response in NZB x NZW mice. We found that 25-week-old mice do produce antibodies reacting with several small nuclear and heterogeneous nuclear (hn) RNP proteins, such as SmD1, U1-70K and hnRNP A2/B1 proteins. The fine specificity of these antibodies was studied with overlapping synthetic peptides. The same antigenically positive and negative peptides were characterized in MRL/Fas(lpr) and NZB x NZW mice in the three proteins. This new finding can help to understand the mechanisms involved in the development of the anti-Sm/RNP antibody response and, particularly, the role played by non-MHC genes in this autoimmune response.
