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Neafsey DE, Lawniczak MKN, Park DJ, Redmond SN, Coulibaly MB, Traoré SF, Sagnon N, Costantini C, Johnson C, Wiegand RC, Collins FH, Lander ES, Wirth DF, Kafatos FC, Besansky NJ, Christophides GK, Muskavitch MAT. SNP genotyping defines complex gene-flow boundaries among African malaria vector mosquitoes. Science 2010; 330:514-517. [PMID: 20966254 DOI: 10.1126/science.1193036] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mosquitoes in the Anopheles gambiae complex show rapid ecological and behavioral diversification, traits that promote malaria transmission and complicate vector control efforts. A high-density, genome-wide mosquito SNP-genotyping array allowed mapping of genomic differentiation between populations and species that exhibit varying levels of reproductive isolation. Regions near centromeres or within polymorphic inversions exhibited the greatest genetic divergence, but divergence was also observed elsewhere in the genomes. Signals of natural selection within populations were overrepresented among genomic regions that are differentiated between populations, implying that differentiation is often driven by population-specific selective events. Complex genomic differentiation among speciating vector mosquito populations implies that tools for genome-wide monitoring of population structure will prove useful for the advancement of malaria eradication.
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Affiliation(s)
| | | | - D J Park
- Broad Institute, Cambridge, MA 02142, USA
| | | | | | - S F Traoré
- Malaria Research and Training Center, Bamako, Mali
| | - N Sagnon
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - C Costantini
- Institut de Recherche pour le Développement, Unité de Recherche R016, Montpellier, France.,Organisation de Coordination pour la Lutte contre les Endémies en Afrique Centrale, Yaounde, Cameroon
| | - C Johnson
- Broad Institute, Cambridge, MA 02142, USA
| | | | - F H Collins
- University of Notre Dame, Notre Dame, IN 46556, USA
| | - E S Lander
- Broad Institute, Cambridge, MA 02142, USA
| | - D F Wirth
- Broad Institute, Cambridge, MA 02142, USA.,Harvard School of Public Health, Boston, MA 02115, USA
| | | | - N J Besansky
- University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - M A T Muskavitch
- Broad Institute, Cambridge, MA 02142, USA.,Harvard School of Public Health, Boston, MA 02115, USA.,Boston College, Chestnut Hill, MA 02467, USA
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Lawniczak MKN, Emrich SJ, Holloway AK, Regier AP, Olson M, White B, Redmond S, Fulton L, Appelbaum E, Godfrey J, Farmer C, Chinwalla A, Yang SP, Minx P, Nelson J, Kyung K, Walenz BP, Garcia-Hernandez E, Aguiar M, Viswanathan LD, Rogers YH, Strausberg RL, Saski CA, Lawson D, Collins FH, Kafatos FC, Christophides GK, Clifton SW, Kirkness EF, Besansky NJ. Widespread divergence between incipient Anopheles gambiae species revealed by whole genome sequences. Science 2010; 330:512-4. [PMID: 20966253 DOI: 10.1126/science.1195755] [Citation(s) in RCA: 223] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The Afrotropical mosquito Anopheles gambiae sensu stricto, a major vector of malaria, is currently undergoing speciation into the M and S molecular forms. These forms have diverged in larval ecology and reproductive behavior through unknown genetic mechanisms, despite considerable levels of hybridization. Previous genome-wide scans using gene-based microarrays uncovered divergence between M and S that was largely confined to gene-poor pericentromeric regions, prompting a speciation-with-ongoing-gene-flow model that implicated only about 3% of the genome near centromeres in the speciation process. Here, based on the complete M and S genome sequences, we report widespread and heterogeneous genomic divergence inconsistent with appreciable levels of interform gene flow, suggesting a more advanced speciation process and greater challenges to identify genes critical to initiating that process.
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Affiliation(s)
- M K N Lawniczak
- Division of Cell and Molecular Biology, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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Affiliation(s)
- F C Kafatos
- THE BIOLOGICAL LABORATORIES, HARVARD UNIVERSITY
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Lycett GJ, McLaughlin LA, Ranson H, Hemingway J, Kafatos FC, Loukeris TG, Paine MJI. Anopheles gambiae P450 reductase is highly expressed in oenocytes and in vivo knockdown increases permethrin susceptibility. Insect Mol Biol 2006; 15:321-7. [PMID: 16756551 DOI: 10.1111/j.1365-2583.2006.00647.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We describe an in vivo model for investigation of detoxification mechanisms of the mosquito Anopheles gambiae, important for the development of malaria control programmes. Cytochrome P450s are involved in metabolic insecticide resistance and require NADPH cytochrome P450 reductase (CPR) to function. Here we demonstrate that the major sites of adult mosquito CPR expression are oenocytes, mid-gut epithelia and head appendages. High CPR expression was also evident in Drosophila oenocytes indicating a general functional role in these insect cells. RNAi mediated knockdown drastically reduced CPR expression in oenocytes, and to a lesser extent in mid-gut epithelia; the head was unaffected. These flies showed enhanced sensitivity to permethrin, demonstrating a key role for abdominal/mid-gut P450s in pyrethroid metabolism, aiding the development of insecticides.
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Affiliation(s)
- G J Lycett
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg D-69117, Germany
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Sim C, Hong YS, Vanlandingham DL, Harker BW, Christophides GK, Kafatos FC, Higgs S, Collins FH. Modulation of Anopheles gambiae gene expression in response to o'nyong-nyong virus infection. Insect Mol Biol 2005; 14:475-81. [PMID: 16164603 PMCID: PMC3840949 DOI: 10.1111/j.1365-2583.2005.00578.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
To determine if gene expression of An. gambiae is modulated in response to o'nyong-nyong virus (ONNV) infection, we utilized cDNA microarrays including about 20 000 cDNAs. Gene expression levels of ONNV-infected female mosquitoes were compared to that of the uninfected control females harvested at 14 days postinfection. In response to ONNV infection, expression levels of 18 genes were significantly modulated, being at least two-fold up- or down-regulated. Quantitative real-time PCR analysis (qRT-PCR) further substantiated the differential expression of six of these genes in response to ONNV infection. These genes have similarity to a putative heat shock protein 70, DAN4, agglutinin attachment subunit, elongation factor 1 alpha and ribosomal protein L35. One gene, with sequence similarity to mitochondrial ribosomal protein L7, was down-regulated in infected mosquitoes. The expression levels and annotation of the differentially expressed genes are discussed in the context of host/virus interaction including host translation/replication factors, and intracellular transport pathways.
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Affiliation(s)
- C Sim
- Center for Tropical Disease Research and Training, University of Notre Dame, Notre Dame, IN 46556, USA
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Vontas J, Blass C, Koutsos AC, David JP, Kafatos FC, Louis C, Hemingway J, Christophides GK, Ranson H. Gene expression in insecticide resistant and susceptible Anopheles gambiae strains constitutively or after insecticide exposure. Insect Mol Biol 2005; 14:509-21. [PMID: 16164607 DOI: 10.1111/j.1365-2583.2005.00582.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A microarray containing approximately 20 000 expressed sequence tags (ESTs; 11 760 unique EST clusters) from the malaria vector, Anopheles gambiae, was used to monitor differences in global gene expression in two insecticide resistant and one susceptible strains. Statistical analysis identified 77 ESTs that were differentially transcribed among the three strains. These include the cytochrome P450 CYP314A1, over-transcribed in the DDT resistant ZAN/U strain, and many genes that belong to families not usually associated with insecticide resistance, such as peptidases, sodium/calcium exchangers and genes implicated in lipid and carbohydrate metabolism. Short-term (6 and 10 h) effects of exposure of the pyrethroid resistant RSP strain to permethrin were also detected. Several genes belonging to enzyme families already implicated in insecticide or xenobiotic detoxification were induced, including the carboxylesterase COEAE2F gene and members of the UDP-glucuronosyl transferase and nitrilase families.
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Affiliation(s)
- J Vontas
- Institute of Molecular Biology and Biotechnology (IMBB-FORTH), Vassilika Vouton, Heraklion, Crete, Greece.
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Abstract
Understanding the molecular mechanisms of the innate immune responses of Anopheles gambiae against Plasmodium parasites is of great importance for current efforts to develop novel strategies for malaria disease control. The parasite undergoes substantial stage-specific losses during its development in the mosquito, which in some cases lead to complete refractoriness of the mosquito against the parasite. The underlying genetics of refractoriness are complex and multifactorial. Completion of the genome sequence of An. gambiae 2 years ago, together with the development of DNA microarrays in this species and the extension of the RNAi technique to adult mosquitoes, has allowed comparative and functional genomic approaches of the mosquito innate immune system. A variety of factors were shown to negatively affect the development of Plasmodium parasites in the mosquito, in some cases leading to complete transmission blockage. In addition, mosquito factors have been identified that play positive roles and are required for successful transmission of the parasite. These findings indicate a highly complex interplay between parasite and vector. Research is continuing to identify new factors involved in this interaction and to decipher the interplay of these molecules and their regulation.
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Affiliation(s)
- K Michel
- European Molecular Biology Laboratory, Meyerhofstr.1, 69117 Heidelberg, Germany
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Gogos JA, Kafatos FC. Determination of sequence preferences of DNA binding proteins using pooled solid-phase sequencing of low degeneracy oligonucleotide mixtures. Methods Mol Biol 2003; 30:295-312. [PMID: 8004203 DOI: 10.1385/0-89603-256-6:295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J A Gogos
- Department of Cellular and Developmental Biology, Harvard University, Cambridge, MA
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Affiliation(s)
- G Dimopoulos
- Department of Biological Sciences, Imperial College of Science, Technology and Medicine, London, UK
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Zhang D, Dimopoulos G, Wolf A, Miñana B, Kafatos FC, Winzerling JJ. Cloning and molecular characterization of two mosquito iron regulatory proteins. Insect Biochem Mol Biol 2002; 32:579-589. [PMID: 11891134 DOI: 10.1016/s0965-1748(01)00138-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Iron regulatory proteins (IRPs) control the synthesis of various proteins at the translational level by binding to iron responsive elements (IREs) in the mRNAs. Iron, infection, and stress can alter IRP/IRE binding activity. Insect messenger RNAs for ferritin and succinate dehydrogenase subunit b have IREs that are active translational control sites. We have cloned and sequenced cDNAs encoding proteins from the IRP1 family for the mosquitoes, Aedes aegypti and Anopheles gambiae. Both deduced amino acid sequences show substantial similarity to human IRP1 and Drosophila IRP1A and IRP1B, and all of the residues thought to be involved in aconitase activity and iron-sulfur cluster formation are conserved. Recombinant A. aegypti IRP1 binds to transcripts of the IREs of mosquito or human ferritin subunit mRNAs. No significant change in A. gambiae IRP1 messenger RNA could be detected during the various developmental stages of the life cycle, following iron loading by blood feeding, or after bacterial or parasitic infections. These data suggest that there is no change in gene transcription. Furthermore, bacterial challenge of A. gambiae cells did not change IRP1 protein levels. In contrast, IRP1 binding activity for the IRE was elevated following immune induction. These data show that changes in IRP1/IRE binding activity occur as part of the insect immune response.
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Affiliation(s)
- D Zhang
- Department of Nutritional Sciences, University of Arizona, Shantz 309, P.O. Box 210038, Tucson, AZ 85721-0038, USA
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Merrill CE, Riesgo-Escovar J, Pitts RJ, Kafatos FC, Carlson JR, Zwiebel LJ. Visual arrestins in olfactory pathways of Drosophila and the malaria vector mosquito Anopheles gambiae. Proc Natl Acad Sci U S A 2002; 99:1633-8. [PMID: 11792843 PMCID: PMC122242 DOI: 10.1073/pnas.022505499] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Arrestins are important components for desensitization of G protein-coupled receptor cascades that mediate neurotransmission as well as olfactory and visual sensory reception. We have isolated AgArr1, an arrestin-encoding cDNA from the malaria vector mosquito, Anopheles gambiae, where olfaction is critical for vectorial capacity. Analysis of AgArr1 expression revealed an overlap between chemosensory and photoreceptor neurons. Furthermore, an examination of previously identified arrestins from Drosophila melanogaster exposed similar bimodal expression, and Drosophila arrestin mutants demonstrate impaired electrophysiological responses to olfactory stimuli. Thus, we show that arrestins in Drosophila are required for normal olfactory physiology in addition to their previously described role in visual signaling. These findings suggest that individual arrestins function in both olfactory and visual pathways in Dipteran insects; these genes may prove useful in the design of control strategies that target olfactory-dependent behaviors of insect disease vectors.
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Affiliation(s)
- C E Merrill
- Department of Biological Sciences, Program in Developmental Biology and Center for Molecular Neuroscience, VU Station B35-1812, Vanderbilt University, Nashville, TN 37235-1812, USA
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Vizioli J, Bulet P, Hoffmann JA, Kafatos FC, Müller HM, Dimopoulos G. Gambicin: a novel immune responsive antimicrobial peptide from the malaria vector Anopheles gambiae. Proc Natl Acad Sci U S A 2001; 98:12630-5. [PMID: 11606751 PMCID: PMC60105 DOI: 10.1073/pnas.221466798] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2001] [Indexed: 11/18/2022] Open
Abstract
A novel mosquito antimicrobial peptide, gambicin, and the corresponding gene were isolated in parallel through differential display-PCR, an expressed sequence tag (EST) project, and characterization of an antimicrobial activity in a mosquito cell line by reverse-phase chromatography. The 616-bp gambicin ORF encodes an 81-residue protein that is processed and secreted as a 61-aa mature peptide containing eight cysteines engaged in four disulfide bridges. Gambicin lacks sequence homology with other known proteins. Like other Anopheles gambiae antimicrobial peptide genes, gambicin is induced by natural or experimental infection in the midgut, fatbody, and hemocyte-like cell lines. Within the midgut, gambicin is predominantly expressed in the anterior part. Both local and systemic gambicin expression is induced during early and late stages of natural malaria infection. In vitro experiments showed that the 6.8-kDa mature peptide can kill both Gram-positive and Gram-negative bacteria, has a morphogenic effect on a filamentous fungus, and is marginally lethal to Plasmodium berghei ookinetes. An oxidized form of gambicin isolated from the cell line medium was more active against bacteria than the nonoxidized form from the same medium.
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Affiliation(s)
- J Vizioli
- Institut de Biologie Moléculaire et Cellulaire, 15 Rue René Descartes, 67084 Strasbourg Cedex, France
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Wang R, Zheng L, Touré YT, Dandekar T, Kafatos FC. When genetic distance matters: measuring genetic differentiation at microsatellite loci in whole-genome scans of recent and incipient mosquito species. Proc Natl Acad Sci U S A 2001; 98:10769-74. [PMID: 11553812 PMCID: PMC58550 DOI: 10.1073/pnas.191003598] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetic distance measurements are an important tool to differentiate field populations of disease vectors such as the mosquito vectors of malaria. Here, we have measured the genetic differentiation between Anopheles arabiensis and Anopheles gambiae, as well as between proposed emerging species of the latter taxon, in whole genome scans by using 23-25 microsatellite loci. In doing so, we have reviewed and evaluated the advantages and disadvantages of standard parameters of genetic distance, F(ST), R(ST), (delta mu)(2), and D. Further, we have introduced new parameters, D' and D(K), which have well defined statistical significance tests and complement the standard parameters to advantage. D' is a modification of D, whereas D(K) is a measure of covariance based on Pearson's correlation coefficient. We find that A. gambiae and A. arabiensis are closely related at most autosomal loci but appear to be distantly related on the basis of X-linked chromosomal loci within the chromosomal Xag inversion. The M and S molecular forms of A. gambiae are practically indistinguishable but differ significantly at two microsatellite loci from the proximal region of the X, outside the Xag inversion. At one of these loci, both M and S molecular forms differ significantly from A. arabiensis, but remarkably, at the other locus, A. arabiensis is indistinguishable from the M molecular form of A. gambiae. These data support the recent proposal of genetically differentiated M and S molecular forms of A. gambiae.
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Affiliation(s)
- R Wang
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69012 Heidelberg, Germany
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Affiliation(s)
- F C Kafatos
- European Molecular Biology Laboratory (EMBL), Postfach 10.2209, 69012, Heidelberg, Germany.
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Dobens LL, Martín-Blanco E, Martínez-Arias A, Kafatos FC, Raftery LA. Drosophila puckered regulates Fos/Jun levels during follicle cell morphogenesis. Development 2001; 128:1845-56. [PMID: 11311164 DOI: 10.1242/dev.128.10.1845] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
puckered (puc) encodes a VH1-like phosphatase that down-regulates Jun kinase (JNK) activity during dorsal closure of the Drosophila embryo. We report a role for puc in follicle cell morphogenesis during oogenesis. puc mRNA accumulates preferentially in the centripetally migrating follicle cells and cells of the elongating dorsal appendages. Proper levels of Puc activity in the follicle cells are critical for the production of a normal egg: either reduced or increased Puc activity result in incomplete nurse cell dumping and aberrant dorsal appendages. Phenotypes associated with puc mutant follicle cells include altered DE-cadherin expression in the follicle cells and a failure of nurse cell dumping to coordinate with dorsal appendage elongation, leading to the formation of cup-shaped egg chambers. The JNK pathway target A251-lacZ showed cell-type-specific differences in its regulation by puc and by the small GTPase DRac1. puc mutant cells displayed region-specific ectopic expression of the A251-lacZ enhancer trap whereas overexpression of a transgene encoding Puc was sufficient to suppress lacZ expression in a cell autonomous fashion. Strikingly, decreased or increased puc function leads to a corresponding increase or decrease, respectively, of Fos and Jun protein levels. Taken together, these data indicate that puc modulates gene expression responses by antagonizing a Ρ GTPase signal transduction pathway that stabilizes the AP-1 transcription factor. Consistent with this, overexpression of a dominant negative DRac1 resulted in lower levels of Fos/Jun.
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Affiliation(s)
- L L Dobens
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
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Levashina EA, Moita LF, Blandin S, Vriend G, Lagueux M, Kafatos FC. Conserved role of a complement-like protein in phagocytosis revealed by dsRNA knockout in cultured cells of the mosquito, Anopheles gambiae. Cell 2001; 104:709-18. [PMID: 11257225 DOI: 10.1016/s0092-8674(01)00267-7] [Citation(s) in RCA: 409] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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.
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Gomulski LM, Pitts RJ, Costa S, Saccone G, Torti C, Polito LC, Gasperi G, Malacrida AR, Kafatos FC, Zwiebel LJ. Genomic organization and characterization of the white locus of the Mediterranean fruitfly, Ceratitis capitata. Genetics 2001; 157:1245-55. [PMID: 11238408 PMCID: PMC1461546 DOI: 10.1093/genetics/157.3.1245] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An approximately 14-kb region of genomic DNA encoding the wild-type white eye (w+) color gene from the medfly, Ceratitis capitata has been cloned and characterized at the molecular level. Comparison of the intron-exon organization of this locus among several dipteran insects reveals distinct organizational patterns that are consistent with the phylogenetic relationships of these flies and the dendrogram of the predicted primary amino acid sequence of the white loci. An examination of w+ expression during medfly development has been carried out, displaying overall similarity to corresponding studies for white gene homologues in Drosophila melanogaster and other insects. Interestingly, we have detected two phenotypically neutral allelic forms of the locus that have arisen as the result of an apparently novel insertion or deletion event located in the large first intron of the medfly white locus. Cloning and sequencing of two mutant white alleles, w1 and w2, from the we,wp and M245 strains, respectively, indicate that the mutant conditions in these strains are the result of independent events--a frameshift mutation in exon 6 for w1 and a deletion including a large part of exon 2 in the case of w2.
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Affiliation(s)
- L M Gomulski
- European Molecular Biology Laboratory, D-69117, Heidelberg, Germany
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Rusten TE, Cantera R, Urban J, Technau G, Kafatos FC, Barrio R. Spalt modifies EGFR-mediated induction of chordotonal precursors in the embryonic PNS of Drosophila promoting the development of oenocytes. Development 2001; 128:711-22. [PMID: 11171396 DOI: 10.1242/dev.128.5.711] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Genes of the spalt family encode nuclear zinc finger proteins. In Drosophila melanogaster, they are necessary for the establishment of head/trunk identity, correct tracheal migration and patterning of the wing imaginal disc. Spalt proteins display a predominant pattern of expression in the nervous system, not only in Drosophila but also in species of fish, mouse, frog and human, suggesting an evolutionarily conserved role for these proteins in nervous system development. Here we show that Spalt works as a cell fate switch between two EGFR-induced cell types, the oenocytes and the precursors of the pentascolopodial organ in the embryonic peripheral nervous system. We show that removal of spalt increases the number of scolopodia, as a result of extra secondary recruitment of precursor cells at the expense of the oenocytes. In addition, the absence of spalt causes defects in the normal migration of the pentascolopodial organ. The dual function of spalt in the development of this organ, recruitment of precursors and migration, is reminiscent of its role in tracheal formation and of the role of a spalt homologue, sem-4, in the Caenorhabditis elegans nervous system.
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Affiliation(s)
- T E Rusten
- European Molecular Biology Laboratory, Meyerhofstrasse, D-69117 Heidelberg, Germany
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Abstract
Anopheles gambiae, the most important vector of malaria, employs its innate immune system in the fight against Plasmodium. This can affect the propagative capacity of Plasmodium in the vector and, in some cases, leads to total refractoriness to the parasite. The components operating in the mosquito's innate immune system and their potential relevance to antimalarial responses are being systematically dissected.
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Affiliation(s)
- G Dimopoulos
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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Giannoni F, Müller HM, Vizioli J, Catteruccia F, Kafatos FC, Crisanti A. Nuclear factors bind to a conserved DNA element that modulates transcription of Anopheles gambiae trypsin genes. J Biol Chem 2001; 276:700-7. [PMID: 11016929 DOI: 10.1074/jbc.m005540200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Anopheles gambiae trypsin family consists of seven genes that are transcribed in the gut of female mosquitoes in a temporal coordinated and mutually exclusive manner, suggesting the involvement of a complex transcription regulatory mechanism. We identified a highly conserved 12-nucleotide motif present in all A. gambiae and Anopheles stephensi trypsin promoters. We investigated the role of this putative trypsin regulatory element (PTRE) in controlling the transcription of the trypsin genes. Gel shift experiments demonstrated that nuclear proteins of A. gambiae cell lines formed two distinct complexes with probes encompassing the PTRE sequence. Mapping of the binding sites revealed that one of the complex has the specificity of a GATA transcription factor. Promoter constructs containing mutations in the PTRE sequence that selectively abolished the binding of either one or both complexes exerted opposite effects on the transcriptional activity of trypsin promoters in A. gambiae and Aedes aegypti cell lines. In addition, the expression of a novel GATA gene was highly enriched in A. gambiae guts. Taken together our data prove that factors binding to the PTRE region are key regulatory elements possibly involved in the blood meal-induced repression and activation of transcription in early and late trypsin genes.
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Affiliation(s)
- F Giannoni
- Department of Biology, Imperial College of Science, Technology and Medicine, Imperial College Road, London SW7 9AX, United Kingdom
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Han YS, Thompson J, Kafatos FC, Barillas-Mury C. Molecular interactions between Anopheles stephensi midgut cells and Plasmodium berghei: the time bomb theory of ookinete invasion of mosquitoes. EMBO J 2000; 19:6030-40. [PMID: 11080150 PMCID: PMC305834 DOI: 10.1093/emboj/19.22.6030] [Citation(s) in RCA: 272] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We present a detailed analysis of the interactions between Anopheles stephensi midgut epithelial cells and Plasmodium berghei ookinetes during invasion of the mosquito by the parasite. In this mosquito, P. berghei ookinetes invade polarized columnar epithelial cells with microvilli, which do not express high levels of vesicular ATPase. The invaded cells are damaged, protrude towards the midgut lumen and suffer other characteristic changes, including induction of nitric oxide synthase (NOS) expression, a substantial loss of microvilli and genomic DNA fragmentation. Our results indicate that the parasite inflicts extensive damage leading to subsequent death of the invaded cell. Ookinetes were found to be remarkably plastic, to secrete a subtilisin-like serine protease and the GPI-anchored surface protein Pbs21 into the cytoplasm of invaded cells, and to be capable of extensive lateral movement between cells. The epithelial damage inflicted is repaired efficiently by an actin purse-string-mediated restitution mechanism, which allows the epithelium to 'bud off' the damaged cells without losing its integrity. A new model, the time bomb theory of ookinete invasion, is proposed and its implications are discussed.
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Affiliation(s)
- Y S Han
- Colorado State University, Pathology Department, Fort Collins, CO 80523, USA
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23
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Catteruccia F, Nolan T, Loukeris TG, Blass C, Savakis C, Kafatos FC, Crisanti A. Stable germline transformation of the malaria mosquito Anopheles stephensi. Nature 2000; 405:959-62. [PMID: 10879538 DOI: 10.1038/35016096] [Citation(s) in RCA: 295] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Anopheline mosquito species are obligatory vectors for human malaria, an infectious disease that affects hundreds of millions of people living in tropical and subtropical countries. The lack of a suitable gene transfer technology for these mosquitoes has hampered the molecular genetic analysis of their physiology, including the molecular interactions between the vector and the malaria parasite. Here we show that a transposon, based on the Minos element and bearing exogenous DNA, can integrate efficiently and stably into the germ line of the human malaria vector Anopheles stephensi, through a transposase-mediated process.
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Affiliation(s)
- F Catteruccia
- Imperial College of Science, Technology and Medicine, London, UK
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24
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Danielli A, Loukeris TG, Lagueux M, Müller HM, Richman A, Kafatos FC. A modular chitin-binding protease associated with hemocytes and hemolymph in the mosquito Anopheles gambiae. Proc Natl Acad Sci U S A 2000; 97:7136-41. [PMID: 10860981 PMCID: PMC16512 DOI: 10.1073/pnas.97.13.7136] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sp22D, a modular serine protease encompassing chitin binding, low density lipoprotein receptor, and scavenger receptor cysteine-rich domains, was identified by molecular cloning in the malaria vector, Anopheles gambiae. It is expressed in multiple body parts and during much of development, most intensely in hemocytes. The protein appears to be posttranslationally modified. Its integral, putatively glycosylated form is secreted in the hemolymph, whereas a smaller form potentially generated by proteolytic processing is associated with the tissues. Bacterial challenge or wounding result in low-level RNA induction, but the protein does not bind to bacteria, nor is its processing affected by infection. However, Sp22D binds to chitin with high affinity and undergoes transient changes in processing during pupal to adult metamorphosis; it may respond to exposure to naked chitin during tissue remodeling or damage.
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Affiliation(s)
- A Danielli
- European Molecular Biology Laboratory, Meyerhofstrasse, 1, 69117 Heidelberg, Germany
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25
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Dimopoulos G, Casavant TL, Chang S, Scheetz T, Roberts C, Donohue M, Schultz J, Benes V, Bork P, Ansorge W, Soares MB, Kafatos FC. Anopheles gambiae pilot gene discovery project: identification of mosquito innate immunity genes from expressed sequence tags generated from immune-competent cell lines. Proc Natl Acad Sci U S A 2000; 97:6619-24. [PMID: 10841561 PMCID: PMC18678 DOI: 10.1073/pnas.97.12.6619] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Together with AIDS and tuberculosis, malaria is at the top of the list of devastating infectious diseases. However, molecular genetic studies of its major vector, Anopheles gambiae, are still quite limited. We have conducted a pilot gene discovery project to accelerate progress in the molecular analysis of vector biology, with emphasis on the mosquito's antimalarial immune defense. A total of 5,925 expressed sequence tags were determined from normalized cDNA libraries derived from immune-responsive hemocyte-like cell lines. The 3,242 expressed sequence tag-containing cDNA clones were grouped into 2,380 clone clusters, potentially representing unique genes. Of these, 1,118 showed similarities to known genes from other organisms, but only 27 were identical to previously known mosquito genes. We identified 38 candidate genes, based on sequence similarity, that may be implicated in immune reactions including antimalarial defense; 19 of these were shown experimentally to be inducible by bacterial challenge, lending support to their proposed involvement in mosquito immunity.
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Affiliation(s)
- G Dimopoulos
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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26
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Benos PV, Gatt MK, Ashburner M, Murphy L, Harris D, Barrell B, Ferraz C, Vidal S, Brun C, Demailles J, Cadieu E, Dreano S, Gloux S, Lelaure V, Mottier S, Galibert F, Borkova D, Minana B, Kafatos FC, Louis C, Sidén-Kiamos I, Bolshakov S, Papagiannakis G, Spanos L, Cox S, Madueño E, de Pablos B, Modolell J, Peter A, Schöttler P, Werner M, Mourkioti F, Beinert N, Dowe G, Schäfer U, Jäckle H, Bucheton A, Callister DM, Campbell LA, Darlamitsou A, Henderson NS, McMillan PJ, Salles C, Tait EA, Valenti P, Saunder RD, Glover DM. From sequence to chromosome: the tip of the X chromosome of D. melanogaster. Science 2000; 287:2220-2. [PMID: 10731137 DOI: 10.1126/science.287.5461.2220] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
One of the rewards of having a Drosophila melanogaster whole-genome sequence will be the potential to understand the molecular bases for structural features of chromosomes that have been a long-standing puzzle. Analysis of 2.6 megabases of sequence from the tip of the X chromosome of Drosophila identifies 273 genes. Cloned DNAs from the characteristic bulbous structure at the tip of the X chromosome in the region of the broad complex display an unusual pattern of in situ hybridization. Sequence analysis revealed that this region comprises 154 kilobases of DNA flanked by 1.2-kilobases of inverted repeats, each composed of a 350-base pair satellite related element. Thus, some aspects of chromosome structure appear to be revealed directly within the DNA sequence itself.
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Affiliation(s)
- P V Benos
- The European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton Hall, Cambridge CB10 1SD, UK
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27
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Catteruccia F, Nolan T, Blass C, Muller HM, Crisanti A, Kafatos FC, Loukeris TG. Toward Anopheles transformation: Minos element activity in anopheline cells and embryos. Proc Natl Acad Sci U S A 2000; 97:2157-62. [PMID: 10681436 PMCID: PMC15770 DOI: 10.1073/pnas.040568397] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of the Minos transposable element to function as a transformation vector in anopheline mosquitoes was assessed. Two recently established Anopheles gambiae cell lines were stably transformed by using marked Minos transposons in the presence of a helper plasmid expressing transposase. The markers were either the green fluorescent protein or the hygromycin B phosphotransferase gene driven by the Drosophila Hsp70 promoter. Cloning and sequencing of the integration sites demonstrated that insertions in the cell genome occurred through the action of Minos transposase. Furthermore, an interplasmid transposition assay established that Minos transposase is active in the cytoplasmic environment of Anopheles stephensi embryos: interplasmid transposition events isolated from injected preblastoderm embryos were identified as Minos transposase-mediated integrations, and no events were recorded in the absence of an active transposase. These results demonstrate that Minos vectors are suitable candidates for germ-line transformation of anopheline mosquitoes.
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Affiliation(s)
- F Catteruccia
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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28
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Affiliation(s)
- F C Kafatos
- European Molecular Molecular Biology Laboratory, Heidelberg, Germany.
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29
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Abstract
Bacterial vectors containing large inserts of genomic DNA are now the standard substrates for large-scale genomic sequencing. Long overlaps between some clones lead to considerable redundant effort. A method for deleting defined regions from bacterial artificial chromosome (BAC) inserts, using homologous recombination, was applied to minimize the overlap between successive BAC clones. This procedure, called trimming, was carried out in the recA(-) BAC host. We have precisely deleted up to 70 kb of DNA from BACs that were to be sequenced. This method requires minimal prior characterization of the clones: collections of BAC end sequences or STS-based maps will accelerate the process. BAC trimming will be useful in both small and large genome sequencing projects and will be of particular utility for gap closure in finishing phases.
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Affiliation(s)
- F Hill
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, D-69117, Germany.
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30
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Vizioli J, Bulet P, Charlet M, Lowenberger C, Blass C, Müller HM, Dimopoulos G, Hoffmann J, Kafatos FC, Richman A. Cloning and analysis of a cecropin gene from the malaria vector mosquito, Anopheles gambiae. Insect Mol Biol 2000; 9:75-84. [PMID: 10672074 DOI: 10.1046/j.1365-2583.2000.00164.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Parasites of the genus Plasmodium are transmitted to mammalian hosts by anopheline mosquitoes. Within the insect vector, parasite growth and development are potentially limited by antimicrobial defence molecules. Here, we describe the isolation of cDNA and genomic clones encoding a cecropin antibacterial peptide from the malaria vector mosquito Anopheles gambiae. The locus was mapped to polytene division 1C of the X chromosome. Cecropin RNA was induced by infection with bacteria and Plasmodium. RNA levels varied in different body parts of the adult mosquito. During development, cecropin expression was limited to the early pupal stage. The peptide was purified from both adult mosquitoes and cell culture supernatants. Anopheles gambiae synthetic cecropins displayed activity against Gram-negative and Gram-positive bacteria, filamentous fungi and yeasts.
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Affiliation(s)
- J Vizioli
- UPR CNRS 9022, Institut de Biologie Moléculaire et Cellulaire, 15, rue René Descartes, Strasbourg Cedex, France
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31
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Ahmed A, Martín D, Manetti AG, Han SJ, Lee WJ, Mathiopoulos KD, Müller HM, Kafatos FC, Raikhel A, Brey PT. Genomic structure and ecdysone regulation of the prophenoloxidase 1 gene in the malaria vector Anopheles gambiae. Proc Natl Acad Sci U S A 1999; 96:14795-800. [PMID: 10611292 PMCID: PMC24727 DOI: 10.1073/pnas.96.26.14795] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Prophenoloxidase, a melanin-synthesizing enzyme, is considered to be an important arthropod immune protein. In mosquitoes, prophenoloxidase has been shown to be involved in refractory mechanisms against malaria parasites. In our study we used Anopheles gambiae, the most important human malaria vector, to characterize the first arthropod prophenoloxidase gene at the genomic level. The complete nucleotide sequence, including the immediate 5' flanking sequence (-855 bp) of the prophenoloxidase 1 gene, was determined. The gene spans 10 kb and is composed of five exons and four introns coding for a 2.5-kb mRNA. In the 5' flanking sequence, we found several putative regulatory motifs, two of which were identified as ecdysteroid regulatory elements. Electrophoretic mobility gel-shift assays and supershift assays demonstrated that the Aedes aegypti ecdysone receptor/Ultraspiracle nuclear receptor complex, and, seemingly, the endogenous Anopheles gambiae nuclear receptor complex, was able to bind one of the ecdysteroid response elements. Furthermore, 20-hydroxyecdysone stimulation was shown to up-regulate the transcription of the prophenoloxidase 1 gene in an A. gambiae cell line.
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Affiliation(s)
- A Ahmed
- Laboratoire de Biochimie et Biologie Moléculaire des Insectes, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France
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32
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Abstract
The malaria parasite suffers severe population losses as it passes through its mosquito vector. Contributing factors are the essential but highly constrained developmental transitions that the parasite undergoes in the mosquito midgut, combined with the invasion of the midgut epithelium by the malaria ookinete (recently described as a principal elicitor of the innate immune response in the Plasmodium-infected insect). Little is known about the molecular organization of these midgut-stage parasites and their critical interactions with the blood meal and the mosquito vector. Elucidation of these molecules and interactions will open up new avenues for chemotherapeutic and immunological attack of parasite development. Here, using the rodent malaria parasite Plasmodium berghei, we identify and characterize the first microneme protein of the ookinete: circumsporozoite- and TRAP-related protein (CTRP). We show that transgenic parasites in which the CTRP gene is disrupted form ookinetes that have reduced motility, fail to invade the midgut epithelium, do not trigger the mosquito immune response, and do not develop further into oocysts. Thus, CTRP is the first molecule shown to be essential for ookinete infectivity and, consequently, mosquito transmission of malaria.
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Affiliation(s)
- J T Dessens
- Infection and Immunity Section, Department of Biology, Imperial College of Science, Technology and Medicine, Sir Alexander Fleming Building, Imperial College Road, London SW7 2AZ, UK
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33
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Barrio R, de Celis JF, Bolshakov S, Kafatos FC. Identification of regulatory regions driving the expression of the Drosophila spalt complex at different developmental stages. Dev Biol 1999; 215:33-47. [PMID: 10525348 DOI: 10.1006/dbio.1999.9434] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The zinc finger transcription factors Spalt and Spalt-related have been implicated in multiple developmental processes. In the wing they are regulated by the secreted protein Decapentaplegic and participate in the positioning of the wing veins. The function of Spalt has been also analyzed during tracheal development and embryonic segmentation. Here, we present the isolation and characterization of novel spalt/spalt-related alleles, which analysis indicates that these genes cannot substitute for each other in the developmental processes studied. The mutants present embryonic or pupal lethality, with phenotypes consistent with the loss of spalt function. We also present a detailed functional analysis of the DNA regions implicated in the regulation of these genes. This regulation is complex, integrating the information from both negative and positive regulators, and it is modular, with discrete fragments of DNA directing expression to discrete regions in embryonic and larval tissues.
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Affiliation(s)
- R Barrio
- European Molecular Biology Laboratory, Heidelberg, D-69117, Germany
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34
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Dimopoulos G, Müller HM, Kafatos FC. How does Anopheles gambiae kill malaria parasites? Parassitologia 1999; 41:169-75. [PMID: 10697851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
The malaria parasite's lifecycle in the mosquito vector Anopheles gambiae involves several translocations within and between tissues during which large parasite losses have been documented. Interestingly, during the critical transition stages of midgut invasion and relocation of sporozoites from the oocysts to the salivary glands the mosquito innate immune system is activated. These defense reactions could, at least partially, be responsible for the parasite killing in the mosquito. This important question is now being approached by the dissection of the mosquito innate immune system as well as genetic and genomic studies.
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Affiliation(s)
- G Dimopoulos
- European Molecular Biology Laboratory, Heidelberg, Germany.
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35
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Collins FH, Saunders RD, Kafatos FC, Roth C, Ke Z, Wang X, Dymbrowski K, Ton L, Hogan J. Genetics in the study of mosquito susceptibility to Plasmodium. Parassitologia 1999; 41:163-8. [PMID: 10697850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Within the past several years, a number of powerful genetic and genomic tools have been developed for use in research on the African malaria vector Anopheles gambiae. While these tools have been developed with a broad range of potential applications in mind, they have been particularly useful in advancing the effort to clone a set of An. gambiae genes that enable a refractory strain of this mosquito to encapsulate and kill a wide variety of different malaria parasites to which this mosquito is normally fully susceptible. This paper describes the latest progress in this map-based cloning research, which involves the collaborative contributions of a number of different laboratories in Europe and the United States.
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Affiliation(s)
- F H Collins
- Department of Biological Sciences, University of Notre Dame, IN 46556, USA.
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36
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Abstract
BACKGROUND NF-kappa B/Rel transcription factors play important roles in immunity and development in mammals and insects. Their activity is regulated by their cellular localization, homo- and heterodimerization and association with other factors on their target gene promoters. Gambif1 from Anopheles gambiae is a member of the Rel family and a close homologue of the morphogen Dorsal, which establishes dorsoventral polarity in the Drosophila embryo. RESULTS We present the crystal structure of the N-terminal specificity domain of Gambif1 bound to DNA. This first structure of an insect Rel protein-DNA complex shows that Gambif1 binds a GGG half-site element using a stack of three arginine sidechains. Differences in affinity to Dorsal binding sites in target gene promoters are predicted to arise from base changes in these GGG elements. An arginine that is conserved in class II Rel proteins (members of which contain a transcription activation domain) contacts the outermost guanines of the DNA site. This previously unseen specific contact contributes strongly to the DNA-binding affinity and might be responsible for differences in specificity between Rel proteins of class I and II. CONCLUSIONS The Gambif1-DNA complex structure illustrates how differences in Dorsal affinity to binding sites in developmental gene promoters are achieved. Comparison with other Rel-DNA complex structures leads to a general model for DNA recognition by Rel proteins.
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Affiliation(s)
- P Cramer
- European Molecular Biology Laboratory, Grenoble Outstation, France
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37
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de Celis JF, Barrio R, Kafatos FC. Regulation of the spalt/spalt-related gene complex and its function during sensory organ development in the Drosophila thorax. Development 1999; 126:2653-62. [PMID: 10331977 DOI: 10.1242/dev.126.12.2653] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nuclear proteins Spalt and Spalt-related belong to a conserved family of transcriptional regulators characterised by the presence of double zinc-finger domains. In the wing, they are regulated by the secreted protein Decapentaplegic and participate in the positioning of the wing veins. Here, we identify regulatory regions in the spalt/spalt-related gene complex that direct expression in the wing disc. The regulatory sequences are organised in independent modules, each of them responsible for expression in particular domains of the wing imaginal disc. In the thorax, spalt and spalt-related are expressed in a restricted domain that includes most proneural clusters of the developing sensory organs in the notum, and are regulated by the signalling molecules Wingless, Decapentaplegic and Hedgehog. We find that spalt/spalt-related participate in the development of sensory organs in the thorax, mainly in the positioning of specific proneural clusters. Later, the expression of at least spalt is eliminated from the sensory organ precursor cells and this is a requisite for the differentiation of these cells. We postulate that spalt and spalt-related belong to a category of transcriptional regulators that subdivide the thorax into expression domains (prepattern) required for the localised activation of proneural genes.
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Affiliation(s)
- J F de Celis
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK.
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38
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Abstract
The concept of innate immunity refers to the first-line host defense that serves to limit infection in the early hours after exposure to microorganisms. Recent data have highlighted similarities between pathogen recognition, signaling pathways, and effector mechanisms of innate immunity in Drosophila and mammals, pointing to a common ancestry of these defenses. In addition to its role in the early phase of defense, innate immunity in mammals appears to play a key role in stimulating the subsequent, clonal response of adaptive immunity.
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Affiliation(s)
- J A Hoffmann
- Institute of Molecular and Cellular Biology, CNRS, Strasbourg, 67084, France.
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39
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Shen Z, Dimopoulos G, Kafatos FC, Jacobs-Lorena M. A cell surface mucin specifically expressed in the midgut of the malaria mosquito Anopheles gambiae. Proc Natl Acad Sci U S A 1999; 96:5610-5. [PMID: 10318932 PMCID: PMC21908 DOI: 10.1073/pnas.96.10.5610] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An invertebrate intestinal mucin gene, AgMuc1, was isolated from the malaria vector mosquito Anopheles gambiae. The predicted 122-residue protein consists of a central core of seven repeating TTTTVAP motifs flanked by hydrophobic N- and C-terminal domains. This structure is similar to that of mucins that coat the protozoan parasite Trypanosoma cruzi. Northern blot analysis indicated that the gene is expressed exclusively in the midgut of adult mosquitoes. A length polymorphism and in situ hybridization were used to genetically and cytogenetically map AgMuc1 to division 7A of the right arm of the second chromosome. The subcellular localization of the encoded protein in tissue culture cells was examined by using a baculovirus vector to express AgMuc1 protein tagged with the green fluorescent protein (GFP). The results indicated that this protein is found at the cell surface and that both hydrophobic domains are required for cell surface targeting. We propose that AgMuc1 is an abundant mucin-like protein that lines the surface of the midgut microvilli, potentially protecting the intestinal epithelium from the proteinase-rich environment of the gut lumen. An intriguing possibility is that, as an abundant surface protein, AgMuc1 may also interact with the malaria parasite during its invasion of the mosquito midgut.
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Affiliation(s)
- Z Shen
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4955, USA
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40
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Müller HM, Dimopoulos G, Blass C, Kafatos FC. A hemocyte-like cell line established from the malaria vector Anopheles gambiae expresses six prophenoloxidase genes. J Biol Chem 1999; 274:11727-35. [PMID: 10206988 DOI: 10.1074/jbc.274.17.11727] [Citation(s) in RCA: 218] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell lines from the malaria vector Anopheles gambiae have been established as a tool for the study of the mosquito innate immune system in vitro. Here, we describe the first continuous insect cell line that produces prophenoloxidase (PPO). This cell line (4a-3B) expresses constitutively six PPO genes, three of which are novel (PPO4, PPO5, and PPO6). The PPO genes show distinct temporal expression profiles in the intact mosquito, spanning stages from the embryo to the adult in an overlapping manner. Transient induction of larva-specific PPO genes in blood-fed adult females suggests that the developmental hormone 20-hydroxyecdysone may be involved in PPO gene regulation. Indeed, exposure of 4a-3B cells to 20-hydroxyecdysone in culture results in induction of those PPO genes that are mainly expressed in early developmental stages, and repression of PPO5, which is preferentially expressed at the adult stage. The cell line shows bacteria-induced immune transcripts that encode defensin and Gram-negative bacteria-binding protein, but no induction of PPO transcripts. This cell line most likely derives from a hemocyte lineage, and represents an appropriate in vitro model for the study of the humoral and cellular immune defenses of A. gambiae.
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Affiliation(s)
- H M Müller
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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41
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Barillas-Mury C, Han YS, Seeley D, Kafatos FC. Anopheles gambiae Ag-STAT, a new insect member of the STAT family, is activated in response to bacterial infection. EMBO J 1999; 18:959-67. [PMID: 10022838 PMCID: PMC1171188 DOI: 10.1093/emboj/18.4.959] [Citation(s) in RCA: 168] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A new insect member of the STAT family of transcription factors (Ag-STAT) has been cloned from the human malaria vector Anopheles gambiae. The domain involved in DNA interaction and the SH2 domain are well conserved. Ag-STAT is most similar to Drosophila D-STAT and to vertebrate STATs 5 and 6, constituting a proposed ancient class A of the STAT family. The mRNA is expressed at all developmental stages, and the protein is present in hemocytes, pericardial cells, midgut, skeletal muscle and fat body cells. There is no evidence of transcriptional activation following bacterial challenge. However, bacterial challenge results in nuclear translocation of Ag-STAT protein in fat body cells and induction of DNA-binding activity that recognizes a STAT target site. In vitro treatment with pervanadate (vanadate and H2O2) translocates Ag-STAT to the nucleus in midgut epithelial cells. This is the first evidence of direct participation of the STAT pathway in immune responses in insects.
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Affiliation(s)
- C Barillas-Mury
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, D-69117, Germany
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Cantera R, Kozlova T, Barillas-Mury C, Kafatos FC. Muscle structure and innervation are affected by loss of Dorsal in the fruit fly, Drosophila melanogaster. Mol Cell Neurosci 1999; 13:131-41. [PMID: 10192771 DOI: 10.1006/mcne.1999.0739] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In Drosophila, the Rel-protein Dorsal and its inhibitor, Cactus, act in signal transduction pathways that control the establishment of dorsoventral polarity during embryogenesis and the immune response during postembryonic life. Here we present data indicating that Dorsal is also involved in the control of development and maintenance of innervation in somatic muscles. Dorsal and Cactus are colocalized in all somatic muscles during postembryonic development. In larvae and adults, these proteins are distributed at low levels in the cytoplasm and nuclei and at much higher levels in the postsynaptic component of glutamatergic neuromuscular junctions. Absence of Dorsal, in homozygous dorsal mutant larvae results in muscle misinsertions, duplications, nuclear hypotrophy, disorganization of actin bundles, and altered subcellular distribution of Cactus. Some muscles show very abnormal neuromuscular junctions, and some motor axon terminals are transformed into growth cone-like structures embedded in synaptotagmin-enriched vesicles. The detailed phenotype suggests a role of Dorsal signalling in the maintenance and plasticity of the NMJ.
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Affiliation(s)
- R Cantera
- Zoology Department, Stockholm University, Stockholm, S-10691, Sweden
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Abstract
The procedures outlined in this article by Rui Wang, Fotis Kafatos and Liangbiao Zheng are well suited to studies of field mosquito populations, and also to the genetic mapping of qualitative and quantitative traits of Anopheles gambiae, a major malaria vector in Africa. An accurate, reproducible and high-throughput microsatellite genotyping procedure has been established.
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Affiliation(s)
- R Wang
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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Dimopoulos G, Seeley D, Wolf A, Kafatos FC. Malaria infection of the mosquito Anopheles gambiae activates immune-responsive genes during critical transition stages of the parasite life cycle. EMBO J 1998; 17:6115-23. [PMID: 9799221 PMCID: PMC1170938 DOI: 10.1093/emboj/17.21.6115] [Citation(s) in RCA: 222] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Six gene markers have been used to map the progress of the innate immune response of the mosquito vector, Anopheles gambiae, upon infection by the malaria parasite, Plasmodium berghei. In addition to four previously reported genes, the set of markers included NOS (a nitric oxide synthase gene fragment) and ICHIT (a gene encoding two putative chitin-binding domains separated by a polythreonine-rich mucin region). In the midgut, a robust response occurs at 24 h post-infection, at a time when malaria ookinetes traverse the midgut epithelium, but subsides at later phases of malaria development. In contrast, the salivary glands show no significant response at 24 h, but are activated in a prolonged late phase when sporozoites are released from the midgut into the haemolymph and invade the glands, between 10 and 25 days after blood feeding. Furthermore, the abdomen of the mosquito minus the midgut shows significant activation of immune markers, with complex kinetics that are distinct from those of both midgut and salivary glands. The parasite evidently elicits immune responses in multiple tissues of the mosquito, two of which are epithelia that the parasite must traverse to complete its development. The mechanisms of these responses and their significance for malaria transmission are discussed.
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Affiliation(s)
- G Dimopoulos
- European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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Kafatos FC. In defense of pure science: Antonio García-Bellido. Int J Dev Biol 1998; 42:539-40. [PMID: 9654047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Kozlova T, Pokholkova GV, Tzertzinis G, Sutherland JD, Zhimulev IF, Kafatos FC. Drosophila hormone receptor 38 functions in metamorphosis: a role in adult cuticle formation. Genetics 1998; 149:1465-75. [PMID: 9649534 PMCID: PMC1460226 DOI: 10.1093/genetics/149.3.1465] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
DHR38 is a member of the steroid receptor superfamily in Drosophila homologous to the vertebrate NGFI-B-type orphan receptors. In addition to binding to specific response elements as a monomer, DHR38 interacts with the USP component of the ecdysone receptor complex in vitro, in yeast and in a cell line, suggesting that DHR38 might modulate ecdysone-triggered signals in the fly. We characterized the molecular structure and expression of the Dhr38 gene and initiated an in vivo analysis of its function(s) in development. The Dhr38 transcription unit spans more than 40 kb in length, includes four introns, and produces at least four mRNA isoforms differentially expressed in development; two of these are greatly enriched in the pupal stage and encode nested polypeptides. We characterized four alleles of Dhr38: a P-element enchancer trap line, l(2)02306, which shows exclusively epidermal staining in the late larval, pre-pupal and pupal stages, and three EMS-induced alleles. Dhr38 alleles cause localized fragility and rupturing of the adult cuticle, demonstrating that Dhr38 plays an important role in late stages of epidermal metamorphosis.
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Affiliation(s)
- T Kozlova
- European Molecular Biology Laboratory, 69012 Heidelberg, Germany.
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Deák P, Omar MM, Saunders RD, Pál M, Komonyi O, Szidonya J, Maróy P, Zhang Y, Ashburner M, Benos P, Savakis C, Siden-Kiamos I, Louis C, Bolshakov VN, Kafatos FC, Madueno E, Modolell J, Glover DM. P-element insertion alleles of essential genes on the third chromosome of Drosophila melanogaster: correlation of physical and cytogenetic maps in chromosomal region 86E-87F. Genetics 1997; 147:1697-722. [PMID: 9409831 PMCID: PMC1208341 DOI: 10.1093/genetics/147.4.1697] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have established a collection of 2460 lethal or semi-lethal mutant lines using a procedure thought to insert single P elements into vital genes on the third chromosome of Drosophila melanogaster. More than 1200 randomly selected lines were examined by in situ hybridization and 90% found to contain single insertions at sites that mark 89% of all lettered subdivisions of the Bridges' map. A set of chromosomal deficiencies that collectively uncover approximately 25% of the euchromatin of chromosome 3 reveal lethal mutations in 468 lines corresponding to 145 complementation groups. We undertook a detailed analysis of the cytogenetic interval 86E-87F and identified 87 P-element-induced mutations falling into 38 complementation groups, 16 of which correspond to previously known genes. Twenty-one of these 38 complementation groups have at least one allele that has a P-element insertion at a position consistent with the cytogenetics of the locus. We have rescued P elements and flanking chromosomal sequences from the 86E-87F region in 35 lines with either lethal or genetically silent P insertions, and used these as probes to identify cosmids and P1 clones from the Drosophila genome projects. This has tied together the physical and genetic maps and has linked 44 previously identified cosmid contigs into seven "super-contigs" that span the interval. STS data for sequences flanking one side of the P-element insertions in 49 lines has identified insertions in the alphagamma element at 87C, two known transposable elements, and the open reading frames of seven putative single copy genes. These correspond to five known genes in this interval, and two genes identified by the homology of their predicted products to known proteins from other organisms.
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Affiliation(s)
- P Deák
- Department of Anatomy and Physiology, University of Dundee, United Kingdom
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Kozlova T, Zhimulev IF, Kafatos FC. Molecular organization of an individual Drosophila polytene chromomere: transcribed sequences in the 10A1-2 band. Mol Gen Genet 1997; 257:55-61. [PMID: 9439569 DOI: 10.1007/s004380050623] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Complete cloning of the DNA in the cytogenetic region 9F12-10A7 has allowed us to analyze the fine structure of an individual polytene chromomere in Drosophila melanogaster. In this report we identify the transcriptionally active fragments within the 10A1-2 band. At least 22 DNA fragments representing multiple distinct transcription units are active during embryogenesis, in third-instar larva or in isolated larval tissues. The transcribed fragments are significantly (at least sevenfold) more numerous than the three genetically defined complementation groups in the 10A1-2 band. One of the transcriptionally active zones detected encompasses a previously unsuspected homologue of the genes Delta and Serrate.
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Affiliation(s)
- T Kozlova
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russian Federation
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