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2005
Moita L F, Wang R, Michel K, Blandin Stéphanie A, Zimmermann T, Levashina Elena A, Kafatos Fotis C
In Vivo Identification of Novel Regulators and Conserved Pathways of Phagocytosis in A. gambiae Journal Article
In: Immunity., vol. 23, no. 1, pp. 65-73, 2005.
Abstract | Links | BibTeX | Tags: blandin, M3i, RNAi
@article{LF2005,
title = {In Vivo Identification of Novel Regulators and Conserved Pathways of Phagocytosis in A. gambiae},
author = {L F Moita and R Wang and K Michel and Stéphanie A Blandin and T Zimmermann and Elena A Levashina and Fotis C Kafatos},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16039580},
year = {2005},
date = {2005-07-01},
journal = {Immunity.},
volume = {23},
number = {1},
pages = {65-73},
abstract = {Anopheles gambiae uses effective immune responses, including phagocytosis, to fight microbial infection. We have developed a semiquantitative phagocytosis test and used it in conjunction with dsRNA gene silencing to test the in vivo roles of 71 candidate genes in phagocytosis of Escherichia coli and Staphylococcus aureus. Here, we show that inactivation of 26 genes changes the phagocytic activity by more than 45% and that two pathways similar to those that mediate apoptotic cell removal in Caenorhabditis elegans are used in A. gambiae for phagocytosis of microorganisms. Simultaneous inactivation of the identified regulators of phagocytosis and conserved components defining each signaling pathway permitted provisional assignment of the novel regulators to one or the other pathway. Pathway inactivation enhances at least three times the ability of E. coli and S. aureus to proliferate in the mosquito. Interestingly, mosquito survival is not compromised even if both pathways are perturbed simultaneously.},
keywords = {blandin, M3i, RNAi},
pubstate = {published},
tppubtype = {article}
}
Anopheles gambiae uses effective immune responses, including phagocytosis, to fight microbial infection. We have developed a semiquantitative phagocytosis test and used it in conjunction with dsRNA gene silencing to test the in vivo roles of 71 candidate genes in phagocytosis of Escherichia coli and Staphylococcus aureus. Here, we show that inactivation of 26 genes changes the phagocytic activity by more than 45% and that two pathways similar to those that mediate apoptotic cell removal in Caenorhabditis elegans are used in A. gambiae for phagocytosis of microorganisms. Simultaneous inactivation of the identified regulators of phagocytosis and conserved components defining each signaling pathway permitted provisional assignment of the novel regulators to one or the other pathway. Pathway inactivation enhances at least three times the ability of E. coli and S. aureus to proliferate in the mosquito. Interestingly, mosquito survival is not compromised even if both pathways are perturbed simultaneously.
2004
Blandin Stéphanie A, Levashina Elena A
Curing mosquitoes to control malaria ? Journal Article
In: Med Sci (Paris)., vol. 20, no. 8-9, pp. 740-2, 2004.
Links | BibTeX | Tags: blandin, M3i, population control
@article{S2004,
title = {Curing mosquitoes to control malaria ?},
author = {Stéphanie A Blandin and Elena A Levashina},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15361335},
year = {2004},
date = {2004-08-02},
journal = {Med Sci (Paris).},
volume = {20},
number = {8-9},
pages = {740-2},
keywords = {blandin, M3i, population control},
pubstate = {published},
tppubtype = {article}
}
Budd A, Blandin Stéphanie A, Levashina Elena A, Gibson T J
Bacterial alpha2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome ? Journal Article
In: Genome Biol., vol. 5, no. 6, pp. R38, 2004.
Abstract | Links | BibTeX | Tags: alpha2-macroglobulins, blandin, M3i
@article{EA2004b,
title = {Bacterial alpha2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome ?},
author = {A Budd and Stéphanie A Blandin and Elena A Levashina and T J Gibson},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15186489},
year = {2004},
date = {2004-05-26},
journal = {Genome Biol.},
volume = {5},
number = {6},
pages = {R38},
abstract = {BACKGROUND: Invasive bacteria are known to have captured and adapted eukaryotic host genes. They also readily acquire colonizing genes from other bacteria by horizontal gene transfer. Closely related species such as Helicobacter pylori and Helicobacter hepaticus, which exploit different host tissues, share almost none of their colonization genes. The protease inhibitor alpha2-macroglobulin provides a major metazoan defense against invasive bacteria, trapping attacking proteases required by parasites for successful invasion. RESULTS: Database searches with metazoan alpha2-macroglobulin sequences revealed homologous sequences in bacterial proteomes. The bacterial alpha2-macroglobulin phylogenetic distribution is patchy and violates the vertical descent model. Bacterial alpha2-macroglobulin genes are found in diverse clades, including purple bacteria (proteobacteria), fusobacteria, spirochetes, bacteroidetes, deinococcids, cyanobacteria, planctomycetes and thermotogae. Most bacterial species with bacterial alpha2-macroglobulin genes exploit higher eukaryotes (multicellular plants and animals) as hosts. Both pathogenically invasive and saprophytically colonizing species possess bacterial alpha2-macroglobulins, indicating that bacterial alpha2-macroglobulin is a colonization rather than a virulence factor. CONCLUSIONS: Metazoan alpha2-macroglobulins inhibit proteases of pathogens. The bacterial homologs may function in reverse to block host antimicrobial defenses. Alpha2-macroglobulin was probably acquired one or more times from metazoan hosts and has then spread widely through other colonizing bacterial species by more than 10 independent horizontal gene transfers. yfhM-like bacterial alpha2-macroglobulin genes are often found tightly linked with pbpC, encoding an atypical peptidoglycan transglycosylase, PBP1C, that does not function in vegetative peptidoglycan synthesis. We suggest that YfhM and PBP1C are coupled together as a periplasmic defense and repair system. Bacterial alpha2-macroglobulins might provide useful targets for enhancing vaccine efficacy in combating infections.},
keywords = {alpha2-macroglobulins, blandin, M3i},
pubstate = {published},
tppubtype = {article}
}
BACKGROUND: Invasive bacteria are known to have captured and adapted eukaryotic host genes. They also readily acquire colonizing genes from other bacteria by horizontal gene transfer. Closely related species such as Helicobacter pylori and Helicobacter hepaticus, which exploit different host tissues, share almost none of their colonization genes. The protease inhibitor alpha2-macroglobulin provides a major metazoan defense against invasive bacteria, trapping attacking proteases required by parasites for successful invasion. RESULTS: Database searches with metazoan alpha2-macroglobulin sequences revealed homologous sequences in bacterial proteomes. The bacterial alpha2-macroglobulin phylogenetic distribution is patchy and violates the vertical descent model. Bacterial alpha2-macroglobulin genes are found in diverse clades, including purple bacteria (proteobacteria), fusobacteria, spirochetes, bacteroidetes, deinococcids, cyanobacteria, planctomycetes and thermotogae. Most bacterial species with bacterial alpha2-macroglobulin genes exploit higher eukaryotes (multicellular plants and animals) as hosts. Both pathogenically invasive and saprophytically colonizing species possess bacterial alpha2-macroglobulins, indicating that bacterial alpha2-macroglobulin is a colonization rather than a virulence factor. CONCLUSIONS: Metazoan alpha2-macroglobulins inhibit proteases of pathogens. The bacterial homologs may function in reverse to block host antimicrobial defenses. Alpha2-macroglobulin was probably acquired one or more times from metazoan hosts and has then spread widely through other colonizing bacterial species by more than 10 independent horizontal gene transfers. yfhM-like bacterial alpha2-macroglobulin genes are often found tightly linked with pbpC, encoding an atypical peptidoglycan transglycosylase, PBP1C, that does not function in vegetative peptidoglycan synthesis. We suggest that YfhM and PBP1C are coupled together as a periplasmic defense and repair system. Bacterial alpha2-macroglobulins might provide useful targets for enhancing vaccine efficacy in combating infections.
Blandin Stéphanie A, Levashina Elena A
Thioester-containing proteins in insect immunity Journal Article
In: Mol Immunol., vol. 40, no. 12, pp. 903-8, 2004.
Abstract | BibTeX | Tags: blandin, M3i, TEP1
@article{S2004b,
title = {Thioester-containing proteins in insect immunity},
author = {Stéphanie A Blandin and Elena A Levashina},
year = {2004},
date = {2004-02-01},
journal = {Mol Immunol.},
volume = {40},
number = {12},
pages = {903-8},
abstract = {Here, we discuss the role of thioester-containing proteins in innate immune responses of insects. TEPs are represented by multi-member families both in the fruitfly, Drosophila melanogaster, and in the mosquito, Anopheles gambiae. Phylogenetic analysis of the family suggests that in these two dipteran species evolution of TEPs followed independent scenarios as a result of specific adaptation to distinct ecological environments. Research on these two relatively simple model systems, which lack adaptive immunity, may provide new insights into the evolutionary origins and functions of this important protein family.},
keywords = {blandin, M3i, TEP1},
pubstate = {published},
tppubtype = {article}
}
Here, we discuss the role of thioester-containing proteins in innate immune responses of insects. TEPs are represented by multi-member families both in the fruitfly, Drosophila melanogaster, and in the mosquito, Anopheles gambiae. Phylogenetic analysis of the family suggests that in these two dipteran species evolution of TEPs followed independent scenarios as a result of specific adaptation to distinct ecological environments. Research on these two relatively simple model systems, which lack adaptive immunity, may provide new insights into the evolutionary origins and functions of this important protein family.
Marco Valeria De, Stier Gunter, Blandin Stephanie A, de Marco Ario
The solubility and stability of recombinant proteins are increased by their fusion to NusA Journal Article
In: Biochem. Biophys. Res. Commun., vol. 322, no. 3, pp. 766–771, 2004, ISSN: 0006-291X.
Abstract | Links | BibTeX | Tags: blandin, Drug Stability, Escherichia coli Proteins, Genetic Vectors, Glutathione Transferase, Kinetics, M3i, Oxidation-Reduction, Peptide Elongation Factors, Recombinant Fusion Proteins, Recombinant Proteins, Solubility, Transcription Factors, Transcriptional Elongation Factors
@article{de_marco_solubility_2004,
title = {The solubility and stability of recombinant proteins are increased by their fusion to NusA},
author = {Valeria De Marco and Gunter Stier and Stephanie A Blandin and Ario de Marco},
doi = {10.1016/j.bbrc.2004.07.189},
issn = {0006-291X},
year = {2004},
date = {2004-01-01},
journal = {Biochem. Biophys. Res. Commun.},
volume = {322},
number = {3},
pages = {766--771},
abstract = {The new bacterial vector pETM60 enables the expression of His-tagged recombinant proteins fused to the C-terminus of NusA through a TEV protease recognition sequence. Three sequences coding for two protein domains (Xklp3A and Tep3Ag) and one membrane-bound viral protein (E8R) could not be expressed in a soluble form in bacteria. Their GST-fusions were mostly soluble but quickly degraded during purification. The same sequences cloned in pETM60 were efficiently purified by metal affinity and recovered soluble after the removal of the fusion partner. The NusA-fused constructs enabled to yield 13-20mg of fusion protein per litre of culture and 2.5-5mg of pure protein per litre of culture. Structural analysis indicated that the purified proteins were monodispersed and correctly folded. NusA has been used to raise antibodies that have been successfully used for Western blot and immunoprecipitation of NusA fusion proteins.},
keywords = {blandin, Drug Stability, Escherichia coli Proteins, Genetic Vectors, Glutathione Transferase, Kinetics, M3i, Oxidation-Reduction, Peptide Elongation Factors, Recombinant Fusion Proteins, Recombinant Proteins, Solubility, Transcription Factors, Transcriptional Elongation Factors},
pubstate = {published},
tppubtype = {article}
}
The new bacterial vector pETM60 enables the expression of His-tagged recombinant proteins fused to the C-terminus of NusA through a TEV protease recognition sequence. Three sequences coding for two protein domains (Xklp3A and Tep3Ag) and one membrane-bound viral protein (E8R) could not be expressed in a soluble form in bacteria. Their GST-fusions were mostly soluble but quickly degraded during purification. The same sequences cloned in pETM60 were efficiently purified by metal affinity and recovered soluble after the removal of the fusion partner. The NusA-fused constructs enabled to yield 13-20mg of fusion protein per litre of culture and 2.5-5mg of pure protein per litre of culture. Structural analysis indicated that the purified proteins were monodispersed and correctly folded. NusA has been used to raise antibodies that have been successfully used for Western blot and immunoprecipitation of NusA fusion proteins.
Blandin Stephanie A, Shiao Shin-Hong, Moita Luis F, Janse Chris J, Waters Andrew P, Kafatos Fotis C, Levashina Elena A
Complement-like protein TEP1 is a determinant of vectorial capacity in the malaria vector Anopheles gambiae Journal Article
In: Cell, vol. 116, no. 5, pp. 661–670, 2004, ISSN: 0092-8674.
Abstract | BibTeX | Tags: Animals, Anopheles, blandin, Female, Genetic, Humans, Insect Proteins, Insect Vectors, M3i, Malaria, Models, Molecular, Plasmodium berghei, Polymorphism, Protein Structure, RNA, Sequence Alignment, Tertiary
@article{blandin_complement-like_2004,
title = {Complement-like protein TEP1 is a determinant of vectorial capacity in the malaria vector Anopheles gambiae},
author = {Stephanie A Blandin and Shin-Hong Shiao and Luis F Moita and Chris J Janse and Andrew P Waters and Fotis C Kafatos and Elena A Levashina},
issn = {0092-8674},
year = {2004},
date = {2004-01-01},
journal = {Cell},
volume = {116},
number = {5},
pages = {661--670},
abstract = {Anopheles mosquitoes are major vectors of human malaria in Africa. Large variation exists in the ability of mosquitoes to serve as vectors and to transmit malaria parasites, but the molecular mechanisms that determine vectorial capacity remain poorly understood. We report that the hemocyte-specific complement-like protein TEP1 from the mosquito Anopheles gambiae binds to and mediates killing of midgut stages of the rodent malaria parasite Plasmodium berghei. The dsRNA knockdown of TEP1 in adults completely abolishes melanotic refractoriness in a genetically selected refractory strain. Moreover, in susceptible mosquitoes this knockdown increases the number of developing parasites. Our results suggest that the TEP1-dependent parasite killing is followed by a TEP1-independent clearance of dead parasites by lysis and/or melanization. Further elucidation of the molecular mechanisms of TEP1-mediated parasite killing will be of great importance for our understanding of the principles of vectorial capacity in insects.},
keywords = {Animals, Anopheles, blandin, Female, Genetic, Humans, Insect Proteins, Insect Vectors, M3i, Malaria, Models, Molecular, Plasmodium berghei, Polymorphism, Protein Structure, RNA, Sequence Alignment, Tertiary},
pubstate = {published},
tppubtype = {article}
}
Anopheles mosquitoes are major vectors of human malaria in Africa. Large variation exists in the ability of mosquitoes to serve as vectors and to transmit malaria parasites, but the molecular mechanisms that determine vectorial capacity remain poorly understood. We report that the hemocyte-specific complement-like protein TEP1 from the mosquito Anopheles gambiae binds to and mediates killing of midgut stages of the rodent malaria parasite Plasmodium berghei. The dsRNA knockdown of TEP1 in adults completely abolishes melanotic refractoriness in a genetically selected refractory strain. Moreover, in susceptible mosquitoes this knockdown increases the number of developing parasites. Our results suggest that the TEP1-dependent parasite killing is followed by a TEP1-independent clearance of dead parasites by lysis and/or melanization. Further elucidation of the molecular mechanisms of TEP1-mediated parasite killing will be of great importance for our understanding of the principles of vectorial capacity in insects.
Blandin Stéphanie A, Levashina Elena A
Mosquito immune responses against malaria parasites Journal Article
In: Curr. Opin. Immunol., vol. 16, no. 1, pp. 16–20, 2004, ISSN: 0952-7915.
Abstract | BibTeX | Tags: Animals, Anopheles, blandin, Gene Library, Genes, Hemocytes, Host-Parasite Interactions, Immunity, Innate, Insect, Insect Vectors, M3i, Malaria, Plasmodium
@article{blandin_mosquito_2004,
title = {Mosquito immune responses against malaria parasites},
author = {Stéphanie A Blandin and Elena A Levashina},
issn = {0952-7915},
year = {2004},
date = {2004-01-01},
journal = {Curr. Opin. Immunol.},
volume = {16},
number = {1},
pages = {16--20},
abstract = {Anopheline mosquitoes are the major vectors of human malaria. Mosquito-parasite interactions are a critical aspect of disease transmission and a potential target for malaria control. Mosquitoes vary in their innate ability to support development of the malaria parasite, but the molecular mechanisms that determine vector competence are poorly understood. This area of research has been revolutionized by recent advances in the mosquito genome characterization and by the development of new tools for functional gene analysis.},
keywords = {Animals, Anopheles, blandin, Gene Library, Genes, Hemocytes, Host-Parasite Interactions, Immunity, Innate, Insect, Insect Vectors, M3i, Malaria, Plasmodium},
pubstate = {published},
tppubtype = {article}
}
Anopheline mosquitoes are the major vectors of human malaria. Mosquito-parasite interactions are a critical aspect of disease transmission and a potential target for malaria control. Mosquitoes vary in their innate ability to support development of the malaria parasite, but the molecular mechanisms that determine vector competence are poorly understood. This area of research has been revolutionized by recent advances in the mosquito genome characterization and by the development of new tools for functional gene analysis.
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}
}
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.
2002
Christophides George K, Zdobnov Evgeny, Barillas-Mury Carolina, Birney Ewan, Blandin Stephanie A, Blass Claudia, Brey Paul T, Collins Frank H, Danielli Alberto, Dimopoulos George, Hetru Charles, Hoa Ngo T, Hoffmann Jules A, Kanzok Stefan M, Letunic Ivica, Levashina Elena A, Loukeris Thanasis G, Lycett Gareth, Meister Stephan, Michel Kristin, Moita Luis F, Müller Hans-Michael, Osta Mike A, Paskewitz Susan M, Reichhart Jean-Marc, Rzhetsky Andrey, Troxler Laurent, Vernick Kenneth D, Vlachou Dina, Volz Jennifer, von Mering Christian, Xu Jiannong, Zheng Liangbiao, Bork Peer, Kafatos Fotis C
Immunity-related genes and gene families in Anopheles gambiae Journal Article
In: Science, vol. 298, no. 5591, pp. 159–165, 2002, ISSN: 1095-9203.
Abstract | Links | BibTeX | Tags: Alternative Splicing, Animals, Anopheles, Apoptosis, bacteria, bioinformatic, blandin, Catechol Oxidase, Computational Biology, Enzyme Precursors, Gene Expression Regulation, Genes, Genetic, Genome, hoffmann, Immunity, Innate, Insect, Insect Proteins, M3i, Multigene Family, Peptides, Phylogeny, Plasmodium, Protein Structure, reichhart, Selection, Serine Endopeptidases, Serpins, Signal Transduction, Tertiary
@article{christophides_immunity-related_2002,
title = {Immunity-related genes and gene families in Anopheles gambiae},
author = {George K Christophides and Evgeny Zdobnov and Carolina Barillas-Mury and Ewan Birney and Stephanie A Blandin and Claudia Blass and Paul T Brey and Frank H Collins and Alberto Danielli and George Dimopoulos and Charles Hetru and Ngo T Hoa and Jules A Hoffmann and Stefan M Kanzok and Ivica Letunic and Elena A Levashina and Thanasis G Loukeris and Gareth Lycett and Stephan Meister and Kristin Michel and Luis F Moita and Hans-Michael Müller and Mike A Osta and Susan M Paskewitz and Jean-Marc Reichhart and Andrey Rzhetsky and Laurent Troxler and Kenneth D Vernick and Dina Vlachou and Jennifer Volz and Christian von Mering and Jiannong Xu and Liangbiao Zheng and Peer Bork and Fotis C Kafatos},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12364793},
doi = {10.1126/science.1077136},
issn = {1095-9203},
year = {2002},
date = {2002-10-01},
journal = {Science},
volume = {298},
number = {5591},
pages = {159--165},
abstract = {We have identified 242 Anopheles gambiae genes from 18 gene families implicated in innate immunity and have detected marked diversification relative to Drosophila melanogaster. Immune-related gene families involved in recognition, signal modulation, and effector systems show a marked deficit of orthologs and excessive gene expansions, possibly reflecting selection pressures from different pathogens encountered in these insects' very different life-styles. In contrast, the multifunctional Toll signal transduction pathway is substantially conserved, presumably because of counterselection for developmental stability. Representative expression profiles confirm that sequence diversification is accompanied by specific responses to different immune challenges. Alternative RNA splicing may also contribute to expansion of the immune repertoire.},
keywords = {Alternative Splicing, Animals, Anopheles, Apoptosis, bacteria, bioinformatic, blandin, Catechol Oxidase, Computational Biology, Enzyme Precursors, Gene Expression Regulation, Genes, Genetic, Genome, hoffmann, Immunity, Innate, Insect, Insect Proteins, M3i, Multigene Family, Peptides, Phylogeny, Plasmodium, Protein Structure, reichhart, Selection, Serine Endopeptidases, Serpins, Signal Transduction, Tertiary},
pubstate = {published},
tppubtype = {article}
}
We have identified 242 Anopheles gambiae genes from 18 gene families implicated in innate immunity and have detected marked diversification relative to Drosophila melanogaster. Immune-related gene families involved in recognition, signal modulation, and effector systems show a marked deficit of orthologs and excessive gene expansions, possibly reflecting selection pressures from different pathogens encountered in these insects' very different life-styles. In contrast, the multifunctional Toll signal transduction pathway is substantially conserved, presumably because of counterselection for developmental stability. Representative expression profiles confirm that sequence diversification is accompanied by specific responses to different immune challenges. Alternative RNA splicing may also contribute to expansion of the immune repertoire.
Blandin Stéphanie A, Moita L F, Kocher T, Wilm M, Kafatos Fotis C, Levashina Elena A
Reverse genetics in the mosquito, Anopheles gambiae : targeted disruption of the Defensin gene Journal Article
In: EMBO Rep., vol. 3, no. 9, pp. 852-6, 2002.
Abstract | Links | BibTeX | Tags: blandin, defensin, M3i
@article{S2002,
title = {Reverse genetics in the mosquito, Anopheles gambiae : targeted disruption of the Defensin gene},
author = {Stéphanie A Blandin and L F Moita and T Kocher and M Wilm and Fotis C Kafatos and Elena A Levashina},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12189180},
year = {2002},
date = {2002-09-02},
journal = {EMBO Rep.},
volume = {3},
number = {9},
pages = {852-6},
abstract = {Anopheles gambiae, the major vector of human malaria parasite, is an important insect model to study vector-parasite interactions. Here, we developed a simple in vivo double-stranded RNA (dsRNA) knockout approach to determine the function of the mosquito antimicrobial peptide gene Defensin. We injected dsRNA into adults and observed efficient and reproducible silencing of Defensin. Analysis of the knockdown phenotype revealed that this peptide is required for the mosquito antimicrobial defense against Gram-positive bacteria. In contrast, in mosquitoes infected by Plasmodium berghei, no loss of mosquito viability and no significant effect on the development and morphology of the parasite midgut stages were observed in the absence of Defensin. We conclude that this peptide is not a major antiparasitic factor in A. gambiae in vivo. Our results open new perspectives for the study of mosquito gene function in vivo and provide a basis for genome-scale systematic functional screens by targeted gene silencing.},
keywords = {blandin, defensin, M3i},
pubstate = {published},
tppubtype = {article}
}
Anopheles gambiae, the major vector of human malaria parasite, is an important insect model to study vector-parasite interactions. Here, we developed a simple in vivo double-stranded RNA (dsRNA) knockout approach to determine the function of the mosquito antimicrobial peptide gene Defensin. We injected dsRNA into adults and observed efficient and reproducible silencing of Defensin. Analysis of the knockdown phenotype revealed that this peptide is required for the mosquito antimicrobial defense against Gram-positive bacteria. In contrast, in mosquitoes infected by Plasmodium berghei, no loss of mosquito viability and no significant effect on the development and morphology of the parasite midgut stages were observed in the absence of Defensin. We conclude that this peptide is not a major antiparasitic factor in A. gambiae in vivo. Our results open new perspectives for the study of mosquito gene function in vivo and provide a basis for genome-scale systematic functional screens by targeted gene silencing.
Levashina Elena A, Blandin Stéphanie A, Moita L F, Lagueux Marie, Kafatos Fotis C
Thioester-Containing Proteins of Protostomes Book Chapter
In: Ezekowitz, Alan R B; Hoffmann, Jules A (Ed.): Chapter Infectious Disease: Innate Immunity., pp. 155-173, Humana Press Inc, Totowa, NJ, 2002.
BibTeX | Tags: blandin, M3i, Thioester-Containing Protein
@inbook{EA2002,
title = {Thioester-Containing Proteins of Protostomes},
author = {Elena A Levashina and Stéphanie A Blandin and L F Moita and Marie Lagueux and Fotis C Kafatos},
editor = {Alan R B Ezekowitz and Jules A Hoffmann},
year = {2002},
date = {2002-06-08},
pages = {155-173},
publisher = {Humana Press Inc, Totowa, NJ},
chapter = {Infectious Disease: Innate Immunity.},
keywords = {blandin, M3i, Thioester-Containing Protein},
pubstate = {published},
tppubtype = {inbook}
}
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}
}
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.