Abstract
The extensive somatic diversification of immune receptors is a hallmark of higher vertebrates. However, whether molecular diversity contributes to immune protection in invertebrates is unknown. We present evidence that Drosophila immune-competent cells have the potential to express more than 18,000 isoforms of the immunoglobulin (Ig)-superfamily receptor Down syndrome cell adhesion molecule (Dscam). Secreted protein isoforms of Dscam were detected in the hemolymph, and hemocyte-specific loss of Dscam impaired the efficiency of phagocytic uptake of bacteria, possibly due to reduced bacterial binding. Importantly, the molecular diversity of Dscam transcripts generated through a mechanism of alternative splicing is highly conserved across major insect orders, suggesting an unsuspected molecular complexity of the innate immune system of insects.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Alternative Splicing*
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Amino Acid Sequence
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Animals
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Animals, Genetically Modified
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Brain / metabolism
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Cell Adhesion Molecules
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Cell Line
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Drosophila Proteins / chemistry
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Drosophila Proteins / genetics*
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Drosophila Proteins / immunology*
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Drosophila Proteins / metabolism
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Drosophila melanogaster / genetics*
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Drosophila melanogaster / immunology*
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Drosophila melanogaster / metabolism
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Escherichia coli / immunology
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Escherichia coli / metabolism
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Fat Body / metabolism
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Hemocytes / immunology
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Hemocytes / metabolism*
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Hemolymph / chemistry
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Immunity, Innate
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Immunoglobulins / chemistry
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Insecta / chemistry
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Insecta / genetics
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Molecular Sequence Data
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Neurons / metabolism
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Oligonucleotide Array Sequence Analysis
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Phagocytosis
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Protein Isoforms / chemistry
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Protein Structure, Tertiary
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RNA Interference
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Receptors, Immunologic / immunology
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Receptors, Immunologic / metabolism
Substances
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Cell Adhesion Molecules
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Drosophila Proteins
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Dscam1 protein, Drosophila
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Immunoglobulins
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Protein Isoforms
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Receptors, Immunologic