101
|
Rossi F, Garavaglia S, Giovenzana GB, Arcà B, Li J, Rizzi M. Crystal structure of the Anopheles gambiae 3-hydroxykynurenine transaminase. Proc Natl Acad Sci U S A 2006; 103:5711-6. [PMID: 16585514 PMCID: PMC1458638 DOI: 10.1073/pnas.0510233103] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Indexed: 11/18/2022] Open
Abstract
In Anopheles gambiae, the vector for the most deadly malaria parasite Plasmodium falciparum, xanthurenic acid (XA) plays a key role in parasite gametogenesis and fertility. In mosquitoes, XA is produced by transamination of 3-hydroxykynurenine (3-HK), a reaction that represents the main route to prevent the accumulation of the potentially toxic 3-HK excess. Interfering with XA metabolism in A. gambiae therefore appears an attractive avenue for the development of malaria transmission-blocking drugs and insecticides. We have determined the crystal structure of A. gambiae 3-HK transaminase in its pyridoxal 5'-phosphate form and in complex with a newly synthesized competitive enzyme inhibitor. Structural inspection of the enzyme active site reveals the key molecular determinants for ligand recognition and catalysis. Major contributions toward inhibitor binding are provided by a salt bridge between the inhibitor carboxylate and Arg-356 and by a remarkable hydrogen bond network involving the anthranilic moiety of the inhibitor and backbone atoms of residues Gly-25 and Asn-44. This study may be useful for the structure-based design of specific enzyme inhibitors of potential interest as antimalarial agents.
Collapse
Affiliation(s)
- Franca Rossi
- Dipartimento di Scienze Chimiche, Alimentari Farmaceutiche e Farmacologiche-Drug and Food Biotechnology Center, University of Piemonte Orientale “Amedeo Avogadro,” Via Bovio 6, 28100 Novara, Italy
| | - Silvia Garavaglia
- Dipartimento di Scienze Chimiche, Alimentari Farmaceutiche e Farmacologiche-Drug and Food Biotechnology Center, University of Piemonte Orientale “Amedeo Avogadro,” Via Bovio 6, 28100 Novara, Italy
| | - Giovanni Battista Giovenzana
- Dipartimento di Scienze Chimiche, Alimentari Farmaceutiche e Farmacologiche-Drug and Food Biotechnology Center, University of Piemonte Orientale “Amedeo Avogadro,” Via Bovio 6, 28100 Novara, Italy
| | - Bruno Arcà
- Dipartimento di Biologia Strutturale e Funzionale, University of Napoli “Federico II,” 80134 Napoli, Italy; and
| | - Jianyong Li
- Department of Biochemistry, Virginia Tech, 111 Engel Hall, Blacksburg, VA 24060
| | - Menico Rizzi
- Dipartimento di Scienze Chimiche, Alimentari Farmaceutiche e Farmacologiche-Drug and Food Biotechnology Center, University of Piemonte Orientale “Amedeo Avogadro,” Via Bovio 6, 28100 Novara, Italy
| |
Collapse
|
102
|
Li J, Riehle MM, Zhang Y, Xu J, Oduol F, Gomez SM, Eiglmeier K, Ueberheide BM, Shabanowitz J, Hunt DF, Ribeiro JMC, Vernick KD. Anopheles gambiae genome reannotation through synthesis of ab initio and comparative gene prediction algorithms. Genome Biol 2006; 7:R24. [PMID: 16569258 PMCID: PMC1557760 DOI: 10.1186/gb-2006-7-3-r24] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 01/19/2006] [Accepted: 02/23/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Complete genome annotation is a necessary tool as Anopheles gambiae researchers probe the biology of this potent malaria vector. RESULTS We reannotate the A. gambiae genome by synthesizing comparative and ab initio sets of predicted coding sequences (CDSs) into a single set using an exon-gene-union algorithm followed by an open-reading-frame-selection algorithm. The reannotation predicts 20,970 CDSs supported by at least two lines of evidence, and it lowers the proportion of CDSs lacking start and/or stop codons to only approximately 4%. The reannotated CDS set includes a set of 4,681 novel CDSs not represented in the Ensembl annotation but with EST support, and another set of 4,031 Ensembl-supported genes that undergo major structural and, therefore, probably functional changes in the reannotated set. The quality and accuracy of the reannotation was assessed by comparison with end sequences from 20,249 full-length cDNA clones, and evaluation of mass spectrometry peptide hit rates from an A. gambiae shotgun proteomic dataset confirms that the reannotated CDSs offer a high quality protein database for proteomics. We provide a functional proteomics annotation, ReAnoXcel, obtained by analysis of the new CDSs through the AnoXcel pipeline, which allows functional comparisons of the CDS sets within the same bioinformatic platform. CDS data are available for download. CONCLUSION Comprehensive A. gambiae genome reannotation is achieved through a combination of comparative and ab initio gene prediction algorithms.
Collapse
Affiliation(s)
- Jun Li
- Center for Microbial and Plant Genomics, and Department of Microbiology, University of Minnesota, St Paul, MN 55108, USA
| | - Michelle M Riehle
- Center for Microbial and Plant Genomics, and Department of Microbiology, University of Minnesota, St Paul, MN 55108, USA
| | - Yan Zhang
- Center for Microbial and Plant Genomics, and Department of Microbiology, University of Minnesota, St Paul, MN 55108, USA
| | - Jiannong Xu
- Center for Microbial and Plant Genomics, and Department of Microbiology, University of Minnesota, St Paul, MN 55108, USA
| | - Frederick Oduol
- Center for Microbial and Plant Genomics, and Department of Microbiology, University of Minnesota, St Paul, MN 55108, USA
| | - Shawn M Gomez
- Unité de Biochimie et Biologie Moléculaire des Insectes and CNRS FRE 2849, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Karin Eiglmeier
- Unité de Biochimie et Biologie Moléculaire des Insectes and CNRS FRE 2849, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Beatrix M Ueberheide
- Department of Chemistry, McCormick Rd, University of Virginia, Charlottesville, VA 22904, USA
| | - Jeffrey Shabanowitz
- Department of Chemistry, McCormick Rd, University of Virginia, Charlottesville, VA 22904, USA
| | - Donald F Hunt
- Department of Chemistry, McCormick Rd, University of Virginia, Charlottesville, VA 22904, USA
| | - José MC Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Kenneth D Vernick
- Center for Microbial and Plant Genomics, and Department of Microbiology, University of Minnesota, St Paul, MN 55108, USA
| |
Collapse
|
103
|
Peterson TM, Luckhart S. A mosquito 2-Cys peroxiredoxin protects against nitrosative and oxidative stresses associated with malaria parasite infection. Free Radic Biol Med 2006; 40:1067-82. [PMID: 16540402 PMCID: PMC2592686 DOI: 10.1016/j.freeradbiomed.2005.10.059] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Revised: 10/23/2005] [Accepted: 10/25/2005] [Indexed: 11/26/2022]
Abstract
Malaria parasite infection in anopheline mosquitoes induces nitrosative and oxidative stresses that limit parasite development, but also damage mosquito tissues in proximity to the response. Based on these observations, we proposed that cellular defenses in the mosquito may be induced to minimize self-damage. Specifically, we hypothesized that peroxiredoxins (Prxs), enzymes known to detoxify reactive oxygen species (ROS) and reactive nitrogen oxide species (RNOS), protect mosquito cells. We identified an Anopheles stephensi 2-Cys Prx ortholog of Drosophila melanogaster Prx-4783, which protects fly cells against oxidative stresses. To assess function, AsPrx-4783 was overexpressed in D. melanogaster S2 and in A. stephensi (MSQ43) cells and silenced in MSQ43 cells with RNA interference before treatment with various ROS and RNOS. Our data revealed that AsPrx-4783 and DmPrx-4783 differ in host cell protection and that AsPrx-4783 protects A. stephensi cells against stresses that are relevant to malaria parasite infection in vivo, namely nitric oxide (NO), hydrogen peroxide, nitroxyl, and peroxynitrite. Further, AsPrx-4783 expression is induced in the mosquito midgut by parasite infection at times associated with peak nitrosative and oxidative stresses. Hence, whereas the NO-mediated defense response is toxic to both host and parasite, AsPrx-4783 may shift the balance in favor of the mosquito.
Collapse
Affiliation(s)
| | - Shirley Luckhart
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA 95616, USA
- Corresponding author. Fax: +1 530 752 8692. E-mail address: (S. Luckhart)
| |
Collapse
|
104
|
Marinotti O, Calvo E, Nguyen QK, Dissanayake S, Ribeiro JMC, James AA. Genome-wide analysis of gene expression in adult Anopheles gambiae. INSECT MOLECULAR BIOLOGY 2006; 15:1-12. [PMID: 16469063 DOI: 10.1111/j.1365-2583.2006.00610.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
With their genome sequenced, Anopheles gambiae mosquitoes now serve as a powerful tool for basic research in comparative, evolutionary and developmental biology. The knowledge generated by these studies is expected to reveal molecular targets for novel vector control and pathogen transmission blocking strategies. Comparisons of gene-expression profiles between adult male and nonblood-fed female Anopheles gambiae mosquitoes revealed that roughly 22% of the genes showed sex-dependent regulation. Blood-fed females switch the majority of their metabolism to blood digestion and egg formation within 3 h after the meal is ingested, in detriment to other activities such as flight and response to environment stimuli. Changes in gene expression are most evident during the first, second and third days after a blood meal, when as many as 50% of all genes showed significant variation in transcript accumulation. After laying the first cluster of eggs (between 72 and 96 h after the blood meal), mosquitoes return to a nongonotrophic stage, similar but not identical to that of 3-day-old nonblood-fed females. Ageing and/or the nutritional state of mosquitoes at 15 days after a blood meal is reflected by the down-regulation of approximately 5% of all genes. A full description of the large number of genes regulated at each analysed time point and each biochemical pathway or biological processes in which they are involved is not possible within the scope of this contribution. Therefore, we present descriptions of groups of genes displaying major differences in transcript accumulation during the adult mosquito life. However, a publicly available searchable database (http://www.angagepuci.bio.uci.edu/) has been made available so that detailed analyses of specific groups of genes based on their descriptions, functions or levels of gene expression variation can be performed by interested investigators according to their needs.
Collapse
Affiliation(s)
- O Marinotti
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | | | | | | | | | | |
Collapse
|
105
|
Ahmed AM, Hurd H. Immune stimulation and malaria infection impose reproductive costs in Anopheles gambiae via follicular apoptosis. Microbes Infect 2006; 8:308-15. [PMID: 16213176 DOI: 10.1016/j.micinf.2005.06.026] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Revised: 06/21/2005] [Accepted: 06/23/2005] [Indexed: 10/25/2022]
Abstract
The employment of defense mechanisms is recognized as a costly life-history trait. In the malaria vector Anopheles gambiae, reproductive costs have been associated with both humoral and cellular innate immune responses and also with malaria infection. The resorption of developing oocytes associated with malaria infection is preceded by the programmed cell death, or apoptosis, of follicular cells. Here we demonstrate that apoptosis in ovarian follicular epithelial cells also occurs when mosquitoes are subjected to artificial immune-elicitors that induce a melanization response or humoral antimicrobial activity. Caspases are key cysteine proteases involved in apoptosis. Caspase-like activity was detected in epithelial cells in approximately 4.0% of the developing ovarian follicles of untreated, blood-fed, mosquitoes. Lipopolysaccharide injection resulted in a significant increase in anti-Micrococcus luteus humoral activity and a significant increase of 257.7% of follicles exhibiting apoptosis compared to results after saline injections. Melanization also triggered follicular apoptosis, which increased by 106.25% or 134.37% in Sephadex C-25 or G-25 bead-inoculated mosquitoes, respectively, compared to that in sham-injected ones. Ovaries from Plasmodium yoelii nigeriensis-infected mosquitoes exhibited a significant increase in follicular apoptosis of 440.9% compared to non-infected ones. Thus, at the time point investigated, infection had a much greater effect than artificial immune-elicitors. Death of follicular epithelial cells has been shown to lead to follicle resorption and hence a decrease in egg production. We propose the trade-off between reproductive fitness and immune defense in A. gambiae operates via the induction of apoptosis in ovarian follicles and that different immune responses impose costs via the same pathway.
Collapse
Affiliation(s)
- Ashraf M Ahmed
- Department of Zoology, Faculty of Sciences, University of El-Minia, El-Minia, Egypt
| | | |
Collapse
|
106
|
Rossi F, Lombardo F, Paglino A, Cassani C, Miglio G, Arcà B, Rizzi M. Identification and biochemical characterization of the Anopheles gambiae 3-hydroxykynurenine transaminase. FEBS J 2005; 272:5653-62. [PMID: 16262702 DOI: 10.1111/j.1742-4658.2005.04961.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spontaneous oxidation of 3-hydroxykynureine (3-HK), a metabolic intermediate of the tryptophan degradation pathway, elicits a remarkable oxidative stress response in animal tissues. In the yellow fever mosquito Aedes aegypti the excess of this toxic metabolic intermediate is efficiently removed by a specific 3-HK transaminase, which converts 3-HK into the more stable compound xanthurenic acid. In anopheline mosquitoes transmitting malaria, xanthurenic acid plays an important role in Plasmodium gametocyte maturation and fertility. Using the sequence information provided by the Anopheles gambiae genome and available ESTs, we adopted a PCR-based approach to isolate a 3-HK transaminase coding sequence from the main human malaria vector A. gambiae. Tissue and developmental expression analysis revealed an almost ubiquitary profile, which is in agreement with the physiological role of the enzyme in mosquito development and 3-HK detoxification. A high yield procedure for the expression and purification of a fully active recombinant version of the protein has been developed. Recombinant A. gambiae 3-HK transaminase is a dimeric pyridoxal 5'-phosphate dependent enzyme, showing an optimum pH of 7.8 and a comparable catalytic efficiency for both 3-HK and its immediate catabolic precursor kynurenine. This study may be useful for the identification of 3-HK transaminase inhibitors of potential interest as malaria transmission-blocking drugs or effective insecticides.
Collapse
Affiliation(s)
- Franca Rossi
- DiSCAFF, University of Piemonte Orientale Amedeo Avogadro, Novara, Italy
| | | | | | | | | | | | | |
Collapse
|
107
|
Vlachou D, Kafatos FC. The complex interplay between mosquito positive and negative regulators of Plasmodium development. Curr Opin Microbiol 2005; 8:415-21. [PMID: 15996894 DOI: 10.1016/j.mib.2005.06.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 06/22/2005] [Indexed: 12/01/2022]
Abstract
The malaria parasite, Plasmodium, requires sexual development in the mosquito before it can be transmitted to the vertebrate host. Mosquito genes are able to substantially modulate this process, which can result in major decreases in parasite numbers. Even in susceptible mosquitoes, haemolymph proteins implicated in systemic immune reactions, together with local epithelial responses, cause lysis of more than 80% of the ookinetes that cross the mosquito midgut. In a refractory mosquito strain, immune responses lead to melanisation of virtually all parasites. Conversely, certain mosquito genes have an opposite effect: they are used by the parasite to evade defence reactions. Detailed understanding of the interplay between positive and negative regulators of parasite development could lead to the generation of novel approaches for malaria control through the vector.
Collapse
Affiliation(s)
- Dina Vlachou
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | | |
Collapse
|
108
|
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 MOLECULAR BIOLOGY 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] [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.
Collapse
Affiliation(s)
- C Sim
- Center for Tropical Disease Research and Training, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | | | | | | | | | | | | |
Collapse
|