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Anopheles gambiae PRS1 modulates Plasmodium development at both midgut and salivary gland steps.

Chertemps T, Mitri C, Perrot S, Sautereau J, Jacques JC, Thiery I, Bourgouin C, Rosinski-Chupin I - PLoS ONE (2010)

Bottom Line: Furthermore, this induction is observed using either the rodent parasite Plasmodium berghei or the human pathogen Plasmodium falciparum.In the midgut, PRS1 overexpression is associated with a relocalization of the protein at the periphery of invaded cells.While providing insights into potential functions of DM9 proteins, our results reveal that PRS1 likely contributes to fundamental interactions between Plasmodium and mosquito epithelia, which do not depend on the specific Anopheles/P. falciparum coevolutionary history.

View Article: PubMed Central - PubMed

Affiliation: Unité de Biochimie et Biologie Moléculaire des Insectes, Département de Parasitologie et Mycologie, Centre National de la Recherche Scientifique URA 3012, Institut Pasteur, Paris, France.

ABSTRACT

Background: Invasion of the mosquito salivary glands by Plasmodium is a critical step for malaria transmission. From a SAGE analysis, we previously identified several genes whose expression in salivary glands was regulated coincident with sporozoite invasion of salivary glands. To get insights into the consequences of these salivary gland responses, here we have studied one of the genes, PRS1 (Plasmodium responsive salivary 1), whose expression was upregulated in infected glands, using immunolocalization and functional inactivation approaches.

Methodology/principal findings: PRS1 belongs to a novel insect superfamily of genes encoding proteins with DM9 repeat motifs of uncharacterized function. We show that PRS1 is induced in response to Plasmodium, not only in the salivary glands but also in the midgut, the other epithelial barrier that Plasmodium has to cross to develop in the mosquito. Furthermore, this induction is observed using either the rodent parasite Plasmodium berghei or the human pathogen Plasmodium falciparum. In the midgut, PRS1 overexpression is associated with a relocalization of the protein at the periphery of invaded cells. We also find that sporozoite invasion of salivary gland cells occurs sequentially and induces intra-cellular modifications that include an increase in PRS1 expression and a relocalization of the corresponding protein into vesicle-like structures. Importantly, PRS1 knockdown during the onset of midgut and salivary gland invasion demonstrates that PRS1 acts as an agonist for the development of both parasite species in the two epithelia, highlighting shared vector/parasite interactions in both tissues.

Conclusions/significance: While providing insights into potential functions of DM9 proteins, our results reveal that PRS1 likely contributes to fundamental interactions between Plasmodium and mosquito epithelia, which do not depend on the specific Anopheles/P. falciparum coevolutionary history.

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Partial phylogenetic tree of the DM9-protein family.DM9 proteins whose genes are located on chromosome 2 in An. gambiae were used for a blast search and the sequences of their closest homologues from different species: Ag, An. gambiae; Ad, An. darlingi; Cq, Culex quinquefasciatus; Aa, A. aegypti; Pp, Phlebotomus papatasi; NaV, Nasonnia vitripennis were aligned, together with two DM9 proteins from Drosophila (Dm: D. melanogaster). The sequence alignment was used to generate an unrooted tree Bootstrap values on 100 replicates are given. The scale bar represents 10% differences in protein sequences. The sequence alignment used to build the tree is shown in Figure S1, a more complete phylogenetic tree is provided in Figure S2 and a list of DM9 proteins with accession numbers is given in Table S1.
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pone-0011538-g001: Partial phylogenetic tree of the DM9-protein family.DM9 proteins whose genes are located on chromosome 2 in An. gambiae were used for a blast search and the sequences of their closest homologues from different species: Ag, An. gambiae; Ad, An. darlingi; Cq, Culex quinquefasciatus; Aa, A. aegypti; Pp, Phlebotomus papatasi; NaV, Nasonnia vitripennis were aligned, together with two DM9 proteins from Drosophila (Dm: D. melanogaster). The sequence alignment was used to generate an unrooted tree Bootstrap values on 100 replicates are given. The scale bar represents 10% differences in protein sequences. The sequence alignment used to build the tree is shown in Figure S1, a more complete phylogenetic tree is provided in Figure S2 and a list of DM9 proteins with accession numbers is given in Table S1.

Mentions: PRS1 (Plasmodium Responsive Salivary 1) was previously described in a salivary gland transcriptome analysis [17] and was identified as upregulated in An. gambiae salivary glands upon invasion by P. berghei sporozoites [15]. The sequence of a corresponding full-length cDNA (BX037582, [18]) indicates that PRS1 potentially encodes a 144 amino acid cytoplasmic protein, containing two DM9 motifs (smart00696). These motifs were first described in Drosophila, where they exist as repeat motifs, in association or not, with other conserved motifs (such as a Ring motif). Proteins with DM9 motifs are essentially found in arthropods and platyhelminths and only occasionally in other eukaryotes or prokaryotes (Table S1). In An. gambiae, five proteins, in addition to PRS1, display DM9 motifs. The corresponding genes are localized in three clusters on An. gambiae chromosomes. The first cluster of genes, comprising AGAP009604, AGAP009605 and AGAP009606, is localized on the An. gambiae chromosome 3R. In AGAP009604, the DM9 motif is associated with a domain homologous to the farnesoic methyl transferases of crustaceans [19]. The two other clusters, respectively coding for PRS1 (AGAP006102) and AGAP006103 on the one hand, and AGAP006398 on the other hand, are found on chromosome 2L of the PEST genome, in the region of the 2La chromosomal inversion near the locus identified as being involved in the control of Plasmodium development [20]. This gene arrangement in clusters is suggestive of an evolution by gene duplication. Phylogenetic analysis reveals that PRS1 and AGAP006103 result from a relatively ancient gene duplication that probably occurred before Anophelinae and Culicinae separation (Fig. 1, S1 and S2). Both proteins share only 50% identical amino acids. Interestingly in PRS1 and AGAP006103, the DM9 motifs are not associated with any other sequence suggesting that they are the support for a putative biological activity.


Anopheles gambiae PRS1 modulates Plasmodium development at both midgut and salivary gland steps.

Chertemps T, Mitri C, Perrot S, Sautereau J, Jacques JC, Thiery I, Bourgouin C, Rosinski-Chupin I - PLoS ONE (2010)

Partial phylogenetic tree of the DM9-protein family.DM9 proteins whose genes are located on chromosome 2 in An. gambiae were used for a blast search and the sequences of their closest homologues from different species: Ag, An. gambiae; Ad, An. darlingi; Cq, Culex quinquefasciatus; Aa, A. aegypti; Pp, Phlebotomus papatasi; NaV, Nasonnia vitripennis were aligned, together with two DM9 proteins from Drosophila (Dm: D. melanogaster). The sequence alignment was used to generate an unrooted tree Bootstrap values on 100 replicates are given. The scale bar represents 10% differences in protein sequences. The sequence alignment used to build the tree is shown in Figure S1, a more complete phylogenetic tree is provided in Figure S2 and a list of DM9 proteins with accession numbers is given in Table S1.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2902509&req=5

pone-0011538-g001: Partial phylogenetic tree of the DM9-protein family.DM9 proteins whose genes are located on chromosome 2 in An. gambiae were used for a blast search and the sequences of their closest homologues from different species: Ag, An. gambiae; Ad, An. darlingi; Cq, Culex quinquefasciatus; Aa, A. aegypti; Pp, Phlebotomus papatasi; NaV, Nasonnia vitripennis were aligned, together with two DM9 proteins from Drosophila (Dm: D. melanogaster). The sequence alignment was used to generate an unrooted tree Bootstrap values on 100 replicates are given. The scale bar represents 10% differences in protein sequences. The sequence alignment used to build the tree is shown in Figure S1, a more complete phylogenetic tree is provided in Figure S2 and a list of DM9 proteins with accession numbers is given in Table S1.
Mentions: PRS1 (Plasmodium Responsive Salivary 1) was previously described in a salivary gland transcriptome analysis [17] and was identified as upregulated in An. gambiae salivary glands upon invasion by P. berghei sporozoites [15]. The sequence of a corresponding full-length cDNA (BX037582, [18]) indicates that PRS1 potentially encodes a 144 amino acid cytoplasmic protein, containing two DM9 motifs (smart00696). These motifs were first described in Drosophila, where they exist as repeat motifs, in association or not, with other conserved motifs (such as a Ring motif). Proteins with DM9 motifs are essentially found in arthropods and platyhelminths and only occasionally in other eukaryotes or prokaryotes (Table S1). In An. gambiae, five proteins, in addition to PRS1, display DM9 motifs. The corresponding genes are localized in three clusters on An. gambiae chromosomes. The first cluster of genes, comprising AGAP009604, AGAP009605 and AGAP009606, is localized on the An. gambiae chromosome 3R. In AGAP009604, the DM9 motif is associated with a domain homologous to the farnesoic methyl transferases of crustaceans [19]. The two other clusters, respectively coding for PRS1 (AGAP006102) and AGAP006103 on the one hand, and AGAP006398 on the other hand, are found on chromosome 2L of the PEST genome, in the region of the 2La chromosomal inversion near the locus identified as being involved in the control of Plasmodium development [20]. This gene arrangement in clusters is suggestive of an evolution by gene duplication. Phylogenetic analysis reveals that PRS1 and AGAP006103 result from a relatively ancient gene duplication that probably occurred before Anophelinae and Culicinae separation (Fig. 1, S1 and S2). Both proteins share only 50% identical amino acids. Interestingly in PRS1 and AGAP006103, the DM9 motifs are not associated with any other sequence suggesting that they are the support for a putative biological activity.

Bottom Line: Furthermore, this induction is observed using either the rodent parasite Plasmodium berghei or the human pathogen Plasmodium falciparum.In the midgut, PRS1 overexpression is associated with a relocalization of the protein at the periphery of invaded cells.While providing insights into potential functions of DM9 proteins, our results reveal that PRS1 likely contributes to fundamental interactions between Plasmodium and mosquito epithelia, which do not depend on the specific Anopheles/P. falciparum coevolutionary history.

View Article: PubMed Central - PubMed

Affiliation: Unité de Biochimie et Biologie Moléculaire des Insectes, Département de Parasitologie et Mycologie, Centre National de la Recherche Scientifique URA 3012, Institut Pasteur, Paris, France.

ABSTRACT

Background: Invasion of the mosquito salivary glands by Plasmodium is a critical step for malaria transmission. From a SAGE analysis, we previously identified several genes whose expression in salivary glands was regulated coincident with sporozoite invasion of salivary glands. To get insights into the consequences of these salivary gland responses, here we have studied one of the genes, PRS1 (Plasmodium responsive salivary 1), whose expression was upregulated in infected glands, using immunolocalization and functional inactivation approaches.

Methodology/principal findings: PRS1 belongs to a novel insect superfamily of genes encoding proteins with DM9 repeat motifs of uncharacterized function. We show that PRS1 is induced in response to Plasmodium, not only in the salivary glands but also in the midgut, the other epithelial barrier that Plasmodium has to cross to develop in the mosquito. Furthermore, this induction is observed using either the rodent parasite Plasmodium berghei or the human pathogen Plasmodium falciparum. In the midgut, PRS1 overexpression is associated with a relocalization of the protein at the periphery of invaded cells. We also find that sporozoite invasion of salivary gland cells occurs sequentially and induces intra-cellular modifications that include an increase in PRS1 expression and a relocalization of the corresponding protein into vesicle-like structures. Importantly, PRS1 knockdown during the onset of midgut and salivary gland invasion demonstrates that PRS1 acts as an agonist for the development of both parasite species in the two epithelia, highlighting shared vector/parasite interactions in both tissues.

Conclusions/significance: While providing insights into potential functions of DM9 proteins, our results reveal that PRS1 likely contributes to fundamental interactions between Plasmodium and mosquito epithelia, which do not depend on the specific Anopheles/P. falciparum coevolutionary history.

Show MeSH
Related in: MedlinePlus