Abstract
The Drosophila immune system discriminates between different classes of infectious microbes and responds with pathogen-specific defense reactions through selective activation of the Toll and the immune deficiency (Imd) signaling pathways. The Toll pathway mediates most defenses against Gram-positive bacteria and fungi, whereas the Imd pathway is required to resist infection by Gram-negative bacteria. The bacterial components recognized by these pathways remain to be defined. Here we report that Gram-negative diaminopimelic acid-type peptidoglycan is the most potent inducer of the Imd pathway and that the Toll pathway is predominantly activated by Gram-positive lysine-type peptidoglycan. Thus, the ability of Drosophila to discriminate between Gram-positive and Gram-negative bacteria relies on the recognition of specific forms of peptidoglycan.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Genetically Modified
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Bacillus thuringiensis / immunology
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Base Sequence
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DNA / genetics
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Drosophila / genetics
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Drosophila / immunology*
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Drosophila / microbiology
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism
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Escherichia coli / immunology
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Gene Expression
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Genes, Insect
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Gram-Negative Bacteria / immunology*
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Gram-Positive Bacteria / immunology*
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Insect Proteins / genetics
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Lac Operon
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Muramidase
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Peptidoglycan / immunology*
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Pseudomonas aeruginosa / immunology
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Receptors, Cell Surface / genetics
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Receptors, Cell Surface / metabolism
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Signal Transduction
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Toll-Like Receptors
Substances
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DptA protein, Drosophila
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Drosophila Proteins
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Insect Proteins
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Peptidoglycan
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Receptors, Cell Surface
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Tl protein, Drosophila
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Toll-Like Receptors
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imd protein, Drosophila
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DNA
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Muramidase