title: Extensive diversity of Ig-superfamily proteins in the immune system of insects.
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.
authors.affiliation: Department of Cancer Biology, Dana Farber Cancer Institute, Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Fiona L
authors.initials: FL
authors.lastname: Watson
authors.forename: Roland
authors.initials: R
authors.lastname: Püttmann-Holgado
authors.forename: Franziska
authors.initials: F
authors.lastname: Thomas
authors.forename: David L
authors.initials: DL
authors.lastname: Lamar
authors.forename: Michael
authors.initials: M
authors.lastname: Hughes
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kondo
authors.forename: Vivienne I
authors.initials: VI
authors.lastname: Rebel
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schmucker
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000378:metabolism; D015815:Cell Adhesion Molecules; D002460:Cell Line; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D004926:Escherichia coli / Q000276:immunology / Q000378:metabolism; D005216:Fat Body / Q000378:metabolism; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism*; D006458:Hemolymph / Q000737:chemistry; D007113:Immunity, Innate; D007136:Immunoglobulins / Q000737:chemistry; D007313:Insecta / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010587:Phagocytosis; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D011971:Receptors, Immunologic / Q000276:immunology / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins; C491736:Dscam1 protein, Drosophila; D007136:Immunoglobulins; D020033:Protein Isoforms; D011971:Receptors, Immunologic