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Lack of an antibacterial response defect in Drosophila Toll-9 mutant.

Narbonne-Reveau K, Charroux B, Royet J - PLoS ONE (2011)

Bottom Line: These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms.To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9.Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection.

View Article: PubMed Central - PubMed

Affiliation: Institut de Biologie du Développement de Marseille-Luminy, CNRS UMR 6216/Aix-Marseille II University, Campus de Luminy, Marseille, France.

ABSTRACT
Toll and Toll-like receptors represent families of receptors involved in mediating innate immunity response in insects and mammals. Although Drosophila proteome contains multiple Toll paralogs, Toll-1 is, so far, the only receptor to which an immune role has been attributed. In contrast, every single mammalian TLR is a key membrane receptor upstream of the vertebrate immune signaling cascades. The prevailing view is that TLR-mediated immunity is ancient. Structural analysis reveals that Drosophila Toll-9 is the most closely related to vertebrate TLRs and utilizes similar signaling components as Toll-1. This suggests that Toll-9 could be an ancestor of TLR-like receptors and could have immune function. Consistently, it has been reported that over-expression of Toll-9 in immune tissues is sufficient to induce the expression of some antimicrobial peptides in flies. These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms. To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9. Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection.

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Related in: MedlinePlus

Resistance to bacterial infection is not impaired in Toll9−/− adults.Survival curves of Toll-9−/−, relishE20 and spzrm7, and control flies in absence of injury, upon clean injury or after septic injury with E. coli, Ecc15 or E. faecalis.
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pone-0017470-g007: Resistance to bacterial infection is not impaired in Toll9−/− adults.Survival curves of Toll-9−/−, relishE20 and spzrm7, and control flies in absence of injury, upon clean injury or after septic injury with E. coli, Ecc15 or E. faecalis.

Mentions: To complete these experiments, we analyzed AMP production and survival of Toll-9−/− flies infected by septic injury. Our results showed that Toll-9−/− mutant flies resist as well as control flies to clean injury and to septic injuries performed with either Gram-positive or Gram-negative bacteria (Figure 7). We next wanted to test whether the humoral antimicrobial response was affected in Toll-9−/− infected mutant. Diptericin mRNA induction upon Ecc15 infection was similar in Toll-9−/− mutant and in controls (Figure S3), indicating that Imd dependent AMP production response was not affected by the absence of Toll-9.


Lack of an antibacterial response defect in Drosophila Toll-9 mutant.

Narbonne-Reveau K, Charroux B, Royet J - PLoS ONE (2011)

Resistance to bacterial infection is not impaired in Toll9−/− adults.Survival curves of Toll-9−/−, relishE20 and spzrm7, and control flies in absence of injury, upon clean injury or after septic injury with E. coli, Ecc15 or E. faecalis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046252&req=5

pone-0017470-g007: Resistance to bacterial infection is not impaired in Toll9−/− adults.Survival curves of Toll-9−/−, relishE20 and spzrm7, and control flies in absence of injury, upon clean injury or after septic injury with E. coli, Ecc15 or E. faecalis.
Mentions: To complete these experiments, we analyzed AMP production and survival of Toll-9−/− flies infected by septic injury. Our results showed that Toll-9−/− mutant flies resist as well as control flies to clean injury and to septic injuries performed with either Gram-positive or Gram-negative bacteria (Figure 7). We next wanted to test whether the humoral antimicrobial response was affected in Toll-9−/− infected mutant. Diptericin mRNA induction upon Ecc15 infection was similar in Toll-9−/− mutant and in controls (Figure S3), indicating that Imd dependent AMP production response was not affected by the absence of Toll-9.

Bottom Line: These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms.To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9.Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection.

View Article: PubMed Central - PubMed

Affiliation: Institut de Biologie du Développement de Marseille-Luminy, CNRS UMR 6216/Aix-Marseille II University, Campus de Luminy, Marseille, France.

ABSTRACT
Toll and Toll-like receptors represent families of receptors involved in mediating innate immunity response in insects and mammals. Although Drosophila proteome contains multiple Toll paralogs, Toll-1 is, so far, the only receptor to which an immune role has been attributed. In contrast, every single mammalian TLR is a key membrane receptor upstream of the vertebrate immune signaling cascades. The prevailing view is that TLR-mediated immunity is ancient. Structural analysis reveals that Drosophila Toll-9 is the most closely related to vertebrate TLRs and utilizes similar signaling components as Toll-1. This suggests that Toll-9 could be an ancestor of TLR-like receptors and could have immune function. Consistently, it has been reported that over-expression of Toll-9 in immune tissues is sufficient to induce the expression of some antimicrobial peptides in flies. These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms. To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9. Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection.

Show MeSH
Related in: MedlinePlus