title: Diversity of animal immune receptors and the origins of recognition complexity in the deuterostomes.
abstract: Invertebrate animals are characterized by extraordinary diversity in terms of body plan, life history and life span. The past impression that invertebrate immune responses are controlled by relatively simple innate systems is increasingly contradicted by genomic analyses that reveal significant evolutionary novelty and complexity. One accessible measure of this complexity is the multiplicity of genes encoding homologs of pattern recognition receptors. These multigene families vary significantly in size, and their sequence character suggests that they vary in function. At the same time, certain aspects of downstream signaling appear to be conserved. Here, we analyze five major classes of immune recognition receptors from newly available animal genome sequences. These include the Toll-like receptors (TLR), Nod-like receptors (NLR), SRCR domain scavenger receptors, peptidoglycan recognition proteins (PGRP), and Gram negative binding proteins (GNBP). We discuss innate immune complexity in the invertebrate deuterostomes, which was first recognized in sea urchins, within the wider context of emerging genomic information across animal phyla.
authors.affiliation: Department of Immunology and Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada. Electronic address: kbuckley@sri.utoronto.ca.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Buckley
authors.affiliation: Department of Immunology and Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Rast
mesh_terms: D000818:Animals; D044822:Biodiversity; D019143:Evolution, Molecular; D014644:Genetic Variation; D016678:Genome / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D007448:Invertebrates / Q000145:classification / Q000235:genetics / Q000276:immunology*; D005810:Multigene Family / Q000235:genetics / Q000276:immunology*; D010802:Phylogeny; D011971:Receptors, Immunologic / Q000145:classification / Q000235:genetics / Q000276:immunology*; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000276:immunology; D051116:Receptors, Scavenger / Q000235:genetics / Q000276:immunology; D013045:Species Specificity; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology
chemical_list: D011971:Receptors, Immunologic; D051192:Receptors, Pattern Recognition; D051116:Receptors, Scavenger; D051193:Toll-Like Receptors
keywords: Deuterostome; Immune recognition; NLR; Sea urchin; TLR