-
[show abstract]
[hide abstract]
ABSTRACT: Chemosensory proteins (CSPs) are a class of soluble proteins present in high concentrations in the sensilla of insect antennae. It has been proposed that they play an important role in insect olfaction by mediating interactions between odorants and odorant receptors. Here we report, for the first time, the presence of five CSP genes in the tsetse fly Glossina morsitans morsitans, a major vector transmitting nagana in livestock. Real-time quantitative reverse transcription PCR showed that three of the CSPs are expressed in antennae. One of them, GmmCSP2, is transcribed at a very high level and could be involved in olfaction. We also determined expression in the antennae of both males and females at different life stages and with different blood feeding regimes. The transcription of GmmCSP2 was lower in male antennae than in females, with a sharp increase in 10-week-old flies, 48 h after a bloodmeal. Thus there is a clear relationship between CSP gene transcription and host searching behaviour. Genome annotation and phylogenetic analyses comparing G. morsitans morsitans CSPs with those of other Diptera showed rapid evolution after speciation of mosquitoes.
Insect Molecular Biology 11/2011; 21(1):41-8. · 2.53 Impact Factor
-
A Pain,
U Böhme,
A E Berry,
K Mungall,
R D Finn,
A P Jackson,
T Mourier,
J Mistry,
E M Pasini,
M A Aslett, [......],
C Churcher,
M A Quail,
A F Cowman,
C M R Turner,
M A Rajandream,
C H M Kocken,
A W Thomas,
C I Newbold,
B G Barrell, M Berriman
[show abstract]
[hide abstract]
ABSTRACT: Plasmodium knowlesi is an intracellular malaria parasite whose natural vertebrate host is Macaca fascicularis (the 'kra' monkey); however, it is now increasingly recognized as a significant cause of human malaria, particularly in southeast Asia. Plasmodium knowlesi was the first malaria parasite species in which antigenic variation was demonstrated, and it has a close phylogenetic relationship to Plasmodium vivax, the second most important species of human malaria parasite (reviewed in ref. 4). Despite their relatedness, there are important phenotypic differences between them, such as host blood cell preference, absence of a dormant liver stage or 'hypnozoite' in P. knowlesi, and length of the asexual cycle (reviewed in ref. 4). Here we present an analysis of the P. knowlesi (H strain, Pk1(A+) clone) nuclear genome sequence. This is the first monkey malaria parasite genome to be described, and it provides an opportunity for comparison with the recently completed P. vivax genome and other sequenced Plasmodium genomes. In contrast to other Plasmodium genomes, putative variant antigen families are dispersed throughout the genome and are associated with intrachromosomal telomere repeats. One of these families, the KIRs, contains sequences that collectively match over one-half of the host CD99 extracellular domain, which may represent an unusual form of molecular mimicry.
Nature 11/2008; 455(7214):799-803. · 36.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The antimicrobial peptide Attacin is an immune effector molecule that can inhibit the growth of gram-negative bacteria. In Glossina morsitans morsitans, which serves as the sole vectors of African trypanosomes, Attacins also play a role in trypanosome resistance, and in maintaining parasite numbers at homeostatic levels in infected individuals. We characterized the attacin encoding loci from a Bacterial Artificial Chromosome (BAC) library. The attacin genes are organized into three clusters. Cluster 1 contains two attacin (attA) genes located in head-to-head orientation, cluster 2 contains two closely related genes (attA and attB) located in a similar transcriptional orientation, and cluster 3 contains a single attacin gene (attD). Coding and transcription regulatory sequences of attA and attB are nearly identical, but differ significantly from attD. Putative AttA and AttB have signal peptide sequences, but lack the pro domain typically present in insect Attacins. Putative AttD lacks both domains. Analysis of attacin cDNA sequences shows polymorphisms that could arise either from allelic variations or from the presence of additional attacin genomic loci. Real time-PCR analysis reveals that attA and attB expression is induced in the fat body of flies per os challenged with Escherichia coli and parasitized with trypanosomes. In the midgut, expression of these attacins is similarly induced following microbial challenge, but reduced in response to parasite infections. Transcription of AttD is significantly less relative to the other two genes, and is preferentially induced in the fat body of parasitized flies. These results indicate that the different attacin genes may be differentially regulated.
Insect Molecular Biology 07/2008; 17(3):293-302. · 2.53 Impact Factor
-
J D Barry,
L Marcello,
L J Morrison,
A F Read,
K Lythgoe,
N Jones,
M Carrington,
G Blandin,
U Böhme,
E Caler,
C Hertz-Fowler,
H Renauld,
N El-Sayed, M Berriman
[show abstract]
[hide abstract]
ABSTRACT: African trypanosomes evade humoral immunity through antigenic variation, whereby they switch expression of the gene encoding their VSG (variant surface glycoprotein) coat. Switching proceeds by duplication of silent VSG genes into a transcriptionally active locus. The genome project has revealed that most of the silent archive consists of hundreds of subtelomeric VSG tandem arrays, and that most of these are not functional genes. Precedent suggests that they can contribute combinatorially to the formation of expressed, functional genes through segmental gene conversion. These findings from the genome project have major implications for evolution of the VSG archive and for transmission of the parasite in the field.
Biochemical Society Transactions 12/2005; 33(Pt 5):986-9. · 3.71 Impact Factor
-
L Eichinger,
J A Pachebat,
G Glöckner,
M-A Rajandream,
R Sucgang, M Berriman,
J Song,
R Olsen,
K Szafranski,
Q Xu, [......],
R L Chisholm,
R Gibbs,
W F Loomis,
M Platzer,
R R Kay,
J Williams,
P H Dear,
A A Noegel,
B Barrell,
A Kuspa
[show abstract]
[hide abstract]
ABSTRACT: The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.
Nature 06/2005; 435(7038):43-57. · 36.28 Impact Factor
-
M Berriman
[show abstract]
[hide abstract]
ABSTRACT: The term 'data mining' can be used to describe any process where useful information is extracted from data with a large background of 'noise'. In the context of a genome project, several stages involve data mining. Amongst the sequence data, 'signals' need to be detected that indicate the presence of interesting features. Often this involves differentiating between transcribed and non-transcribed bases to predict coding regions. After detection, defining the roles of these sequences involves sifting through multiple lines of evidence. If these roles are accurately reflected in genome annotation, they can be used by researchers to frame queries and interrogate the data further.
Parasitology 02/2004; 128 Suppl 1:S23-31. · 2.96 Impact Factor
-
M A Harris,
J Clark,
A Ireland,
J Lomax,
M Ashburner,
R Foulger,
K Eilbeck,
S Lewis,
B Marshall,
C Mungall, [......],
M Gwinn,
L Hannick,
J Wortman, M Berriman,
V Wood,
N de la Cruz,
P Tonellato,
P Jaiswal,
T Seigfried,
R White
[show abstract]
[hide abstract]
ABSTRACT: The Gene Ontology (GO) project (http://www. geneontology.org/) provides structured, controlled vocabularies and classifications that cover several domains of molecular and cellular biology and are freely available for community use in the annotation of genes, gene products and sequences. Many model organism databases and genome annotation groups use the GO and contribute their annotation sets to the GO resource. The GO database integrates the vocabularies and contributed annotations and provides full access to this information in several formats. Members of the GO Consortium continually work collectively, involving outside experts as needed, to expand and update the GO vocabularies. The GO Web resource also provides access to extensive documentation about the GO project and links to applications that use GO data for functional analyses.
Nucleic Acids Research 02/2004; 32(Database issue):D258-61. · 8.03 Impact Factor
-
M A Harris,
J Clark,
A Ireland,
J Lomax,
M Ashburner,
R Foulger,
K Eilbeck,
S Lewis,
B Marshall,
C Mungall, [......],
M Gwinn,
L Hannick,
J Wortman, M Berriman,
V Wood,
N Cruz,
P Tonellato,
P Jaiswal,
T Seigfried,
R White
Nucleic Acids Res. 01/2004; 32(Database issue):258-261.
-
[show abstract]
[hide abstract]
ABSTRACT: Tsetse flies transmit African trypanosomiasis leading to half a million cases annually. Trypanosomiasis in animals (nagana) remains a massive brake on African agricultural development. While trypanosome biology is widely studied, knowledge of tsetse flies is very limited, particularly at the molecular level. This is a serious impediment to investigations of tsetse-trypanosome interactions. We have undertaken an expressed sequence tag (EST) project on the adult tsetse midgut, the major organ system for establishment and early development of trypanosomes.
A total of 21,427 ESTs were produced from the midgut of adult Glossina morsitans morsitans and grouped into 8,876 clusters or singletons potentially representing unique genes. Putative functions were ascribed to 4,035 of these by homology. Of these, a remarkable 3,884 had their most significant matches in the Drosophila protein database. We selected 68 genes with putative immune-related functions, macroarrayed them and determined their expression profiles following bacterial or trypanosome challenge. In both infections many genes are downregulated, suggesting a malaise response in the midgut. Trypanosome and bacterial challenge result in upregulation of different genes, suggesting that different recognition pathways are involved in the two responses. The most notable block of genes upregulated in response to trypanosome challenge are a series of Toll and Imd genes and a series of genes involved in oxidative stress responses.
The project increases the number of known Glossina genes by two orders of magnitude. Identification of putative immunity genes and their preliminary characterization provides a resource for the experimental dissection of tsetse-trypanosome interactions.
Genome biology 02/2003; 4(10):R63. · 6.63 Impact Factor
-
N Hall,
A Pain, M Berriman,
C Churcher,
B Harris,
D Harris,
K Mungall,
S Bowman,
R Atkin,
S Baker, [......],
K Stevens,
K Taylor,
A Tivey,
L Unwin,
S Whitehead,
J Woodward,
J E Sulston,
A Craig,
C Newbold,
B G Barrell
[show abstract]
[hide abstract]
ABSTRACT: Since the sequencing of the first two chromosomes of the malaria parasite, Plasmodium falciparum, there has been a concerted effort to sequence and assemble the entire genome of this organism. Here we report the sequence of chromosomes 1, 3-9 and 13 of P. falciparum clone 3D7--these chromosomes account for approximately 55% of the total genome. We describe the methods used to map, sequence and annotate these chromosomes. By comparing our assemblies with the optical map, we indicate the completeness of the resulting sequence. During annotation, we assign Gene Ontology terms to the predicted gene products, and observe clustering of some malaria-specific terms to specific chromosomes. We identify a highly conserved sequence element found in the intergenic region of internal var genes that is not associated with their telomeric counterparts.
Nature 11/2002; 419(6906):527-31. · 36.28 Impact Factor
-
Trends in Parasitology 11/2001; 17(10):463-4. · 5.14 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cyclosporin A (CsA) is a potent anti-malarial compound in vitro and in vivo in mice though better known for its immunosuppressive properties in humans. Crystal structures of wild-type and a double mutant Plasmodium falciparum cyclophilin (PfCyP19 and mPfCyP19) complexed with CsA have been determined using diffraction terms to a resolution of 2.1 A (1 A=0.1 nm). The wild-type has a single PfCyP19/CsA complex per asymmetric unit in space group P1 and refined to an R-work of 0.15 and R-free of 0.19. An altered cyclophilin, with two accidental mutations, Phe120 to Leu in the CsA binding pocket and Leu171 to Trp at the C terminus, presents two complexes per asymmetric unit in the orthorhombic space group P2(1)2(1)2. This refined to an R-work of 0.18 and R-free 0.21. The mutations were identified from the crystallographic analysis and the C-terminal alteration helps to explain the different crystal forms obtained. PfCyP19 shares approximately 61 % sequence identity with human cyclophilin A (hCyPA) and the structures are similar, consisting of an eight-stranded antiparallel beta-barrel core capped by two alpha-helices. The fold creates a hydrophobic active-site, the floor of which is formed by side-chains of residues from four antiparallel beta-strands and the walls from loops and turns. We identified C-H.O hydrogen bonds between the drug and protein that may be an important feature of cyclophilins and suggest a general mode of interaction between hydrophobic molecules. Comparisons with cyclophilin-dipeptide complexes suggests that a specific C-H.O hydrogen bonding interaction may contribute to ligand binding. Residues Ser106, His99 and Asp130, located close to the active site and conserved in most cyclophilins, are arranged in a manner reminiscent of a serine protease catalytic triad. A Ser106Ala mutant was engineered to test the hypothesis that this triad contributes to CyP function. Mutant and wild-type enzymes were found to have similar catalytic properties.
Journal of Molecular Biology 05/2000; 298(1):123-33. · 4.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Two major protein phosphatase (PP) activities were purified from cytosolic extracts of the erythrocytic stage of the malaria parasite, Plasmodium falciparum. Both enzymes were specific for phosphoserine and phosphothreonine residues with very little activity against phosphotyrosine residues. The biochemical properties of the enzymes suggested their strong similarity with eukaryotic PP2A and PP2B protein phosphatases. Both enzymes preferentially dephosphorylated the alpha subunit of phosphorylase kinase, and were resistant to inhibitor-1. The PP2A-like enzyme required Mn2+ for activity and was inhibited by nanomolar concentrations of okadaic acid (OA). The cDNA sequence of the PP2A-like enzyme was identified through a match of its predicted amino acid sequence with the N-terminal sequence of the catalytic subunit. The PP2B-like (calcineurin) enzyme was stimulated by calmodulin and Ca2+ or Ni2+, but was resistant to OA. Malarial calcineurin was strongly and specifically inhibited by cyclosporin A (CsA) only in the presence of wild type P. falciparum cyclophilin but not a mutant cyclophilin. The inhibition was noncompetitive, and provides a potential explanation for the cyclosporin-sensitivity of the parasite. There was no significant quantitative difference in the total protein Ser/Thr phosphatase activity among the ring, trophozoite, and schizont stages.
Molecular and Biochemical Parasitology 05/1999; 99(2):167-81. · 2.55 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Trypanothione reductase (TR) helps to maintain an intracellular reducing environment in trypanosomatids, a group of protozoan parasites that afflict humans and livestock in tropical areas. This protective function is achieved via reduction of polyamine-glutathione conjugates, in particular trypanothione. TR has been validated as a chemotherapeutic target by molecular genetics methods. To assist the development of new therapeutics, we have characterised the structure of TR from the pathogen Trypanosoma cruzi complexed with the substrate trypanothione and have used the structure to guide database searches and molecular modelling studies.
The TR-trypanothione-disulfide structure has been determined to 2.4 A resolution. The chemical interactions involved in enzyme recognition and binding of substrate can be inferred from this structure. Comparisons with the related mammalian enzyme, glutathione reductase, explain why each enzyme is so specific for its own substrate. A CH***O hydrogen bond can occur between the active-site histidine and a carbonyl of the substrate. This interaction contributes to enzyme specificity and mechanism by producing an electronic induced fit when substrate binds. Database searches and molecular modelling using the substrate as a template and the active site as receptor have identified a class of cyclic-polyamine natural products that are novel TR inhibitors.
The structure of the TR-trypanothione enzyme-substrate complex provides details of a potentially valuable drug target. This information has helped to identify a new class of enzyme inhibitors as novel lead compounds worthy of further development in the search for improved medicines to treat a range of parasitic infections.
Structure 02/1999; 7(1):81-9. · 6.35 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cyclosporin (Cs) A has pronounced antimalarial activity in vitro and in vivo. In other organisms, the drug is thought to exert its effects either by inhibiting the peptidylprolyl cis/trans isomerase activity of cyclophilin (CyP) or by forming a CyP-CsA complex that inhibits the phosphatase activity of calcineurin. We have cloned and overexpressed in Escherichia coli a gene encoding a CyP from Plasmodium falciparum (PfCyP19) that is located on chromosome 3. The sequence of PfCyP19 shows remarkable sequence identity with human CyPA and, unlike the two previously identified CyPs from P. falciparum, PfCyP19 has no signal peptide or N-terminal sequence extension, suggesting a cytosolic localization. All the residues implicated in the recognition of the synthetic substrate N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide are conserved, resulting in characteristically high Michaelis-Menten and specificity constants (Km>120 microM, kcat/Km=1.2x10(7) M-1.s-1 respectively). As the first line in the functional characterization of this enzyme, we have assessed its binding affinity for CsA. In accordance with its tryptophan-containing CsA-binding domain, PfCyP19 binds CsA with high affinity (Kd=13 nM, Ki=6.9 nM). Twelve CsA analogues were also found to possess Ki values similar to CsA, with the notable exceptions of Val2-Cs (Ki=218 nM) and Thr2-Cs (Ki=690 nM). The immunosuppressants rapamycin and FK506 were inactive as inhibitors, consistent with other members of the CyP family of rotamases. The CsA analogues were also assessed as inhibitors of P. falciparum growth in vitro. Although their antimalarial activity did not correlate with inhibition of enzyme activity, residues 3 and 4 of CsA appeared to be important for inhibition of parasite growth and residues 1 and 2 for PfCyP19 inhibition. We propose that a malarial CyP-CsA complex presents residues 3 and 4 as part of an 'effector surface' for recognition by a downstream target, similar to the proposed mechanism for T-cell immunosuppression.
Biochemical Journal 10/1998; 334 ( Pt 2):437-45. · 4.90 Impact Factor
-
AC Ivens,
CS Peacock,
EA Worthey,
L. Murphy,
G Aggarwal, M Berriman,
E Sisk,
MA Rajandream,
E Adlem,
R Aert, [......],
C Bauser,
A Beck,
SM Beverley,
G Bianchettin,
K Borzym,
G Bothe,
CV Bruschi,
M Collins,
E Cadag,
Ciarlo
-
[show abstract]
[hide abstract]
ABSTRACT: Two major protein phosphatase (PP) activities were purified from cytosolic extracts of the erythrocytic stage of the malaria parasite, Plasmodium falciparum. Both enzymes were specific for phosphoserine and phosphothreonine residues with very little activity against phosphotyrosine residues. The biochemical properties of the enzymes suggested their strong similarity with eukaryotic PP2A and PP2B protein phosphatases. Both enzymes preferentially dephosphorylated the a subunit of phosphorylase kinase, and were resistant to inhibitor-1. The PP2A-like enzyme required Mn2+ for activity and was inhibited by nanomolar concentrations of okadaic acid (OA). The cDNA sequence of the PP2A-like enzyme was identified through a match of its predicted amino acid sequence with the N-terminal sequence of the catalytic subunit. The PP2B-like (calcineurin) enzyme was stimulated by calmodulin and Ca2+ or Ni2+, but was resistant to OA. Malarial calcineurin was strongly and specifically inhibited by cyclosporin A (CsA) only in the presence of wild type P. falciparum cyclophilin but not a mutant cyclophilin. The inhibition was noncompetitive, and provides a potential explanation for the cyclosporin-sensitivity of the parasite. There was no significant quantitative difference in the total protein Ser/Thr phosphatase activity among the ring, trophozoite, and schizont stages. (C) 1999 Elsevier Science B.V. All rights reserved
Molecular and Biochemical Parasitology. 99.
-
[show abstract]
[hide abstract]
ABSTRACT: Cyclosporin A (CsA) is a potent anti-malarial compound in vitro and in vivo in mice though better known for its immunosuppressive properties in humans. Crystal structures of wild-type and a double mutant Plasmodium falciparum cyclophilin (PfCyP19 and mPfCyP19) complexed with CsA have been determined using diffraction terms to a resolution of 2.1 Angstrom (1 Angstrom = 0.1 nm). The wild-type has a single PfCyP19/CsA complex per asymmetric unit in space group P1 and refined to an X-work of 0.15 and X-free of 0.19. An altered cyclophilin, with two accidental mutations, Phe120 to Leu in the CsA binding pocket and Leu171 to Trp at the C terminus, presents two complexes per asymmetric unit in the orthorhombic space group P2(1)2(1)2. This refined to an X-work of 0.18 and X-free 0.21. The mutations were identified from the crystallographic analysis and the C-terminal alteration helps to explain the different crystal forms obtained. PfCyP19 shares approximately 61% sequence identity with human cyclophilin A (hCyPA) and the structures are similar, consisting of an eight-stranded antiparallel beta-barrel core capped by two alpha-helices. The fold creates a hydrophobic active-site, the floor of which is formed by side-chains of residues from four antiparallel beta- strands and the walls from loops and turns. We identified C-H ... O hydrogen bonds between the drug and protein that may be an important feature of cyclophilins and suggest a general mode of interaction between hydrophobic molecules. Comparisons with cyclophilin-dipeptide complexes suggests that a specific C-H ... O hydrogen bonding interaction may contribute to ligand binding. Residues Ser106, His99 and Asp130, located close to the active site and conserved in most cyclophilins, are arranged in a manner reminiscent of a serine protease catalytic triad. A Ser106Ala mutant was engineered to test the hypothesis that this triad contributes to CyP function. Mutant and wild- type enzymes were found to have similar catalytic properties. (C) 2000 Academic Press
Journal of Molecular Biology. 298(1).
-
N Hall, M Berriman,
NJ Lennard,
BR Harris,
C Hertz-Fowler,
EN Bart-Delabesse,
CS Gerrard,
RJ Atkin,
AJ Barron,
S Bowman, [......],
CH Corton,
A Cronin,
R Davies,
J. Doggett,
A Fraser,
E Gruter,
S Hall,
AD Harper,
MP Kay,
V Leech
-
M Berriman,
E. Ghedin,
C Hertz-Fowler,
G Blandin,
H Renauld,
DC Bartholomeu,
NJ Lennard,
E Caler,
NE Hamlin,
B Haas, [......],
J. Shallom,
L Marcello,
LH Hou,
B Wickstead,
UCM Alsmark,
C. Arrowsmith,
RJ Atkin,
AJ Barron,
F Bringaud,
Broo
