Characterization of four Toll related genes during development and immune responses in Anopheles gambiae

Luna, Coralia; Wang, Xuelan; Huang, Yaming; Zhang, Jian; Zheng, Liyun

doi:10.1016/s0965-1748(02)00053-x

Cited by 48 publications

(37 citation statements)

References 37 publications

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“…In many insect species, including An. gambiae, genes involved in processes such as development (i.e., pupal cuticular and chitin-binding proteins) [27][28][29][30][31] and immune response (i.e., Toll receptor-like proteins) 27,[32][33][34] are highly expressed during the pupal stage. Once a fully formed adult has emerged, there is continued gene expression in response to environmental and physiological changes , as well as other key genes (i.e., sperm specific protein and cytochrome P450 metabolism enzymes) 27,36 .…”

Section: Discussionmentioning

confidence: 99%

RNAi Trigger Delivery into <em>Anopheles gambiae</em> Pupae

Regna

Harrison

Heyse

et al. 2016

JoVE

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RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel.

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Section: Discussionmentioning

confidence: 99%

RNAi Trigger Delivery into <em>Anopheles gambiae</em> Pupae

Regna

Harrison

Heyse

et al. 2016

JoVE

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“…Under the right subcellular environment, the disulfide bond formation may stabilize the multimer, leading to stimulation of the pathway. Interestingly, the wild-type Toll-9 protein lacks the full complement of cysteines within this motif and exhibits similarly high drosomycin-stimulating activity (22,40), indicating that a wild-type Toll member can use such a mechanism to regulate the signaling pathway.…”

Section: Discussionmentioning

confidence: 99%

Multimerization and interaction of Toll and Spätzle in Drosophila

Yagi

Tanji

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

112

102

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The Toll family of receptors is required for innate immune response to pathogen-associated molecules, but the mechanism of signaling is not entirely clear. In Drosophila the prototypic Toll regulates both embryonic development and adult immune response. We demonstrate here that the host protein Spä tzle can function as a ligand for Toll because Spä tzle forms a complex with Toll in transgenic fly extracts and stimulates the expression of a Tolldependent immunity gene, drosomycin, in adult flies. We also show that constitutively active mutants of Toll form multimers that contain intermolecular disulfide linkages. These disulfide linkages are critical for the activity of one of these mutant receptors, indicating that multimerization is essential for the constitutive activity. Furthermore, systematic mutational analysis revealed that a conserved cysteine-containing motif, different from the cysteines used for the intermolecular disulfide linkages, serves as a selfinhibitory module of Toll. Deleting or mutating this cysteinecontaining motif leads to constitutive activity. This motif is located just outside the transmembrane domain and may provide a structural hindrance for multimerization and activation of Toll. Together, our results suggest that multimerization may be a regulated, essential step for Toll-receptor activation.U pon infection, insects mount a rapid but rather nonspecific response. This insect antimicrobial response is similar to the mammalian innate immune response (1-7). The recognition receptors of the innate immune system have limited diversity and are designed to recognize pathogen-associated molecules such as lipopolysaccharides and peptidoglycans, which are common molecules found in groups of microorganisms. Toll and Toll-like receptors (TLRs) are a conserved family of recognition receptors in insects and mammals (5, 6). The Toll family of receptors is essential for innate immunity, but it is unclear how the receptors interact with microbial substances and host ligands.In Drosophila, the prototypic Toll receptor was first identified as an essential component for embryonic development (8). Subsequently, Toll was also shown to be essential for the induced expression of a subset of antimicrobial peptides during antifungal and anti-Gram-positive bacterial responses (9, 10). The regulation of the anti-Gram-negative bacterial response depends on a second pathway called the Immune deficiency (Imd) pathway, which controls the expression of another subset of antimicrobial peptides (2-4, 11). The induced expression of antimicrobial peptides through these two pathways is critical for Drosophila to survive microbial infections (12).The mechanism by which Toll receptors transmit the signal of infection across the cell membrane is not clear. Many components of the Toll pathway in the Drosophila innate immune response have been identified. The extracellular components include a peptidoglycan recognition protein (PGRP-SA), a serine protease (Persephone), a serine protease inhibitor (Necrotic), and a putative li...

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“…gambiae (TOLL 1A, 1B, 5A and 5B) and three from Ae. aegypti (Toll1A, Toll1B, and Toll5A) have been suggested to form an orthologue group with the fruit fly Toll (Toll-1) and Toll-5 (Tehao) (14,19). An additional search using TBLASTN against the Ae.…”

Section: Diversity Expansion Of Toll and Spz In Ae Aegypti-fourmentioning

confidence: 99%

“…Toll-related receptors are characterized by TIR, a 150-amino acid intra-cytoplasmic domain, which has been found in members of the interleukin-1 receptor family and plant disease resistance genes (28). Although the presence of C-terminal extension distinguished the Toll1 group (Drosophila Toll, Anopheles TOLL1A and TOLL1B, Aedes Toll1A and Toll1B) from Toll5 group (Drosophila Toll-5, Anopheles TOLL5A and TOLL5B, Aedes Toll5A) (19,24), our phylogenetic studies with whole published amino acid sequences (data not shown) or TIR domains (Fig. 1A) of Toll receptors indicated that these five Aedes Tolls (Toll1A, Toll1B, Toll5A, Toll5B, and Toll4) and four Anopheles Tolls (TOLL1A, TOLL1B, TOLL5A, and TOLL5B) formed a phylogenetic cluster with Drosophila Toll and Toll-5 (Fig.…”

Section: Diversity Expansion Of Toll and Spz In Ae Aegypti-fourmentioning

confidence: 99%

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A Toll Receptor and a Cytokine, Toll5A and Spz1C, Are Involved in Toll Antifungal Immune Signaling in the Mosquito Aedes aegypti

Shin¹,

Bian²,

Raikhel

2006

Journal of Biological Chemistry

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The fungal-specific immune response in the mosquito Aedes aegypti involves the Toll immune pathway transduced through REL1, a homologue of the NF-B transcription factor Drosophila Dorsal. The Toll receptor and its ligand, Spätzle (Spz), link extracellular immune signals to the Toll intracellular transduction pathway. Five homologues to the Drosophila Toll (Toll1) receptor (Toll1A, Toll1B, Toll5A, Toll5B, and Toll4) and three homologues to the Drosophila cytokine Spätzle (Spz1A, 1B, and 1C) were identified from genomic and cDNA sequence data bases. Toll1A, Toll5A, Toll5B, and Spz1A were specifically induced in the mosquito fat body following fungal challenge. This transcriptional up-regulation was mediated by REL1. Spz1C was constitutively expressed in the mosquito fat body, whereas Spz1B and Toll4 were primarily expressed in ovarian tissues of female mosquitoes. The transcripts of Toll1B were only detected in early stages of mosquito embryos. RNA interference knock down of Toll5A and Spz1C resulted in two phenotypes of Aedes Toll/REL1 pathway deficiency: decreased induction of Aedes Serpin-27A following fungal challenge and increased susceptibility to the entomopathogenic fungus Beauveria bassiana. These data suggest that Toll5A and Spz1C function as cytokine receptor systems specific to the Toll receptormediated immune response following fungal challenge in the mosquito fat body.Mosquitoes are vectors of numerous human diseases, including malaria, which is responsible for over two million deaths per year (1, 2). Other mosquito-borne diseases, such as dengue fever (3), the West Nile encephalitis virus (4), and lymphatic filariasis (5), are also the cause of morbidity and mortality despite enormous control efforts. Innate immunity plays a pivotal role in the interaction between a pathogen and its vector; therefore, studies on vector immunity and its interaction with pathogens are essential for future development of novel control strategies against these vector-borne diseases.

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Characterization of four Toll related genes during development and immune responses in Anopheles gambiae

Cited by 48 publications

References 37 publications

RNAi Trigger Delivery into <em>Anopheles gambiae</em> Pupae

RNAi Trigger Delivery into <em>Anopheles gambiae</em> Pupae

Multimerization and interaction of Toll and Spätzle in Drosophila

A Toll Receptor and a Cytokine, Toll5A and Spz1C, Are Involved in Toll Antifungal Immune Signaling in the Mosquito Aedes aegypti

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