Independent evolution of Toll and related genes in insects and mammals

Luo, C.; Zheng, Liyun

doi:10.1007/s002510050017

Cited by 78 publications

(45 citation statements)

References 29 publications

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“…In more recent studies, Toll-like receptors were found to be responsible in nonadaptive, innate resistance to microbes. These receptors are shared between arthropods (including mosquitoes) and vertebrates (193). Furthermore, although little is known about the molecules in immune responses induced in arthropod cells, activation of several genes encoding anti-microbial peptides was confirmed in mosquito cells infected with WNV (213).…”

Section: Pathology and Resistance To Viral Infectionmentioning

confidence: 95%

Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends

2005

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SUMMARY Among animal viruses, arboviruses are unique in that they depend on arthropod vectors for transmission. Field research and laboratory investigations related to the three components of this unique mode of transmission, virus, vector, and vertebrate host, have produced an enormous amount of valuable information that may be found in numerous publications. However, despite many reviews on specific viruses, diseases, or interests, a systematic approach to organizing the available information on all facets of biological transmission and then to interpret it in the context of the evolutionary process has not been attempted before. Such an attempt in this review clearly demonstrates tremendous progress made worldwide to characterize the viruses, to comprehend disease transmission and pathogenesis, and to understand the biology of vectors and their role in transmission. The rapid progress in molecular biologic techniques also helped resolve many virologic puzzles and yielded highly valuable data hitherto unavailable, such as characterization of virus receptors, the genetic basis of vertebrate resistance to viral infection, and phylogenetic evidence of the history of host range shifts in arboviruses. However, glaring gaps in knowledge of many critical subjects, such as the mechanism of viral persistence and the existence of vertebrate reservoirs, are still evident. Furthermore, with the accumulated data, new questions were raised, such as evolutionary directions of virus virulence and of host range. Although many fundamental questions on the evolution of this unique mode of transmission remained unresolved in the absence of a fossil record, available observations for arboviruses and the information derived from studies in other fields of the biological sciences suggested convergent evolution as a plausible process. Overall, discussion of the diverse range of theories proposed and observations made by many investigators was found to be highly valuable for sorting out the possible mechanism(s) of the emergence of arboviral diseases.

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Section: Pathology and Resistance To Viral Infectionmentioning

confidence: 95%

Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends

2005

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“…1A). The eight Drosophila Toll-related proteins share higher similarity between them than with any mammalian TLR, suggesting that these two groups of proteins have evolved independently (11,20). The Drosophila Tolls fall into several subsets, as illustrated in Fig.…”

Section: A Family Of Toll Receptors In Drosophilamentioning

confidence: 99%

“…Toll-5 and Toll-8 were both initially identified as genomic clones sequenced by Berkeley Drosophila Genome Project and have been recently described under the names of tehao (GenBank accession no. AF140019) (20) and Tollo (GenBank accession no. AF204158), respectively.…”

Section: Methodsmentioning

confidence: 99%

Toll-related receptors and the control of antimicrobial peptide expression inDrosophila

Tauszig

Jouanguy²,

Hoffmann³

et al. 2000

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

355

300

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Insects defend themselves against infectious microorganisms by synthesizing potent antimicrobial peptides. Drosophila has appeared in recent years as a favorable model to study this innate host defense. A genetic analysis of the regulation of the antifungal peptide drosomycin has demonstrated a key role for the transmembrane receptor Toll, which prompted the search for mammalian homologs. Two of these, Toll-like receptor (TLR)2 and TLR4, recently were shown to play a critical role in innate immunity against bacteria. Here we describe six additional Toll-related genes (Toll-3 to Toll-8) in Drosophila in addition to 18-wheeler. Two of these genes, Toll-3 and Toll-4, are expressed at a low level. Toll-6, -7, and -8, on the other hand, are expressed at high levels during embryogenesis and molting, suggesting that, like Toll and 18w, they perform developmental functions. Finally, Toll-5 is expressed only in larvae and adults. By using chimeric constructs, we have tested the capacity of the signaling Toll͞IL-1R homology domains of these receptors to activate antimicrobial peptide promoters and found that only Toll and Toll-5 can activate the drosomycin promoter in transfected cells, thus demonstrating specificity at the level of the Toll͞IL-1R homology domain. In contrast, none of these constructs activated antibacterial peptide promoters, suggesting that Toll-related receptors are not involved in the regulation of antibacterial peptide expression. This result was independently confirmed by the demonstration that a dominant-negative version of the kinase Pelle can block induction of drosomycin by the cytokine Spaetzle, but does not affect induction of the antibacterial peptide attacin by lipopolysaccharide.

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“…These signaling pathways regulate expression of antimicrobial peptides that are active against Gram-positive and Gramnegative bacteria, as well as fungi (Anderson, 2000;Tauszig et al, 2000;Hoffmann and Reichhart, 2002;Rutschmann et al, 2002). A large family of Toll-related receptor genes has been identified from a number of insects including Toll, (Toll-3 to -9), 18-wheeler, Trex, Tollo and Tehao (Eldon et al, 1994;Williams et al, 1997;Luo and Zheng, 2000;Luna et al, 2002;Bilak et al, 2003). Toll-related receptors are a group of evolutionarily conserved proteins with diverse biological functions.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a honey bee Toll related receptor gene Am18w and its potential involvement in antimicrobial immune defense

Aronstein

Saldivar

2005

Apidologie

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-Toll receptors are involved in intracellular signal transduction and initiation of insect antimicrobial immune responses. Here we report the isolation and characterization of a novel gene (Am18w) from honey bee Apis mellifera, which encodes for the Toll-like receptor and shares a striking 51.4% similarity with Bombyx mori 18-wheeler, 46.6% with Drosophila Toll-7 receptor and 42.5% with Drosophila 18-wheeler. The sequence analysis of the deduced 18W protein revealed a conserved TollInterleukin-Resistance signaling domain (TIR) characteristic of signal transducing receptors found in Toll and mammalian interleukin 1 (IL-1) receptors. The expression profiles of the honey bee Toll-like receptor gene Am18w were examined in all developmental stages, before and after immune challenge. Here we demonstrate that injection of a dsRNA probe into honey bee larvae successfully disrupts the endogenous mRNA of the target gene and allows us to examine the effects of Am18w gene silencing (RNAi) on the expression level of antimicrobial peptides.Toll receptor / gene silencing / antimicrobial peptides / immune response / honey bee / Apis mellifera

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Independent evolution of Toll and related genes in insects and mammals

Cited by 78 publications

References 29 publications

Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends

Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends

Toll-related receptors and the control of antimicrobial peptide expression inDrosophila

Characterization of a honey bee Toll related receptor gene Am18w and its potential involvement in antimicrobial immune defense

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