title: Genomic insights into the immune system of the sea urchin.
abstract: Comparative analysis of the sea urchin genome has broad implications for the primitive state of deuterostome host defense and the genetic underpinnings of immunity in vertebrates. The sea urchin has an unprecedented complexity of innate immune recognition receptors relative to other animal species yet characterized. These receptor genes include a vast repertoire of 222 Toll-like receptors, a superfamily of more than 200 NACHT domain-leucine-rich repeat proteins (similar to nucleotide-binding and oligomerization domain (NOD) and NALP proteins of vertebrates), and a large family of scavenger receptor cysteine-rich proteins. More typical numbers of genes encode other immune recognition factors. Homologs of important immune and hematopoietic regulators, many of which have previously been identified only from chordates, as well as genes that are critical in adaptive immunity of jawed vertebrates, also are present. The findings serve to underscore the dynamic utilization of receptors and the complexity of immune recognition that may be basal for deuterostomes and predicts features of the ancestral bilaterian form.
authors.affiliation: Sunnybrook Research Institute and Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Room S-126B, Toronto, Ontario M4N 3M5, Canada. jrast@sri.utoronto.ca
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Rast
authors.forename: L Courtney
authors.initials: LC
authors.lastname: Smith
authors.forename: Mariano
authors.initials: M
authors.lastname: Loza-Coll
authors.forename: Taku
authors.initials: T
authors.lastname: Hibino
authors.forename: Gary W
authors.initials: GW
authors.lastname: Litman
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D005803:Genes, Immunoglobulin; D016654:Genes, RAG-1; D016678:Genome; D007107:Immune System / Q000502:physiology*; D007113:Immunity, Innate / Q000235:genetics*; D007155:Immunologic Factors / Q000235:genetics* / Q000502:physiology; D005810:Multigene Family; D010802:Phylogeny; D011971:Receptors, Immunologic / Q000235:genetics* / Q000502:physiology; D051192:Receptors, Pattern Recognition / Q000235:genetics; D047270:Strongylocentrotus purpuratus / Q000235:genetics* / Q000276:immunology*; D051193:Toll-Like Receptors / Q000235:genetics / Q000502:physiology; D014714:Vertebrates / Q000235:genetics / Q000276:immunology
chemical_list: D004268:DNA-Binding Proteins; D007155:Immunologic Factors; D011971:Receptors, Immunologic; D051192:Receptors, Pattern Recognition; D051193:Toll-Like Receptors