title: Phylogenetic analysis and expression profiling of the pattern recognition receptors: Insights into molecular recognition of invading pathogens in Manduca sexta.
abstract: Pattern recognition receptors (PRRs) detect microbial pathogens and trigger innate immune responses. Previous biochemical studies have elucidated the physiological functions of eleven PRRs in Manduca sexta but our understanding of the recognition process is still limited, lacking genomic perspectives. While 34 C-type lectin-domain proteins and 16 Toll-like receptors are reported in the companion papers, we present here 120 other putative PRRs identified through the genome annotation. These include 76 leucine-rich repeat (LRR) proteins, 14 peptidoglycan recognition proteins, 6 EGF/Nim-domain proteins, 5 β-1,3-glucanase-related proteins, 4 galectins, 4 fibrinogen-related proteins, 3 thioester proteins, 5 immunoglobulin-domain proteins, 2 hemocytins, and 1 Reeler. Sequence alignment and phylogenetic analysis reveal the evolution history of a diverse repertoire of proteins for pathogen recognition. While functions of insect LRR proteins are mostly unknown, their structure diversification is phenomenal: In addition to the Toll homologs, 22 LRR proteins with a signal peptide are expected to be secreted; 18 LRR proteins lacking signal peptides may be cytoplasmic; 36 LRRs with a signal peptide and a transmembrane segment may be non-Toll receptors on the surface of cells. Expression profiles of the 120 genes in 52 tissue samples reflect complex regulation in various developmental stages and physiological states, including some likely by Rel family transcription factors via κB motifs in the promoter regions. This collection of information is expected to facilitate future biochemical studies detailing their respective roles in this model insect.
authors.affiliation: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Cao
authors.affiliation: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Ramesh T
authors.initials: RT
authors.lastname: Gunaratna
authors.affiliation: Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Yun-ru
authors.initials: YR
authors.lastname: Chen
authors.affiliation: Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Blissard
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kanost
authors.affiliation: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA. Electronic address: haobo.jiang@okstate.edu.
authors.forename: Haobo
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000818:Animals; D020869:Gene Expression Profiling; D049750:Genome, Insect; D007113:Immunity, Innate / Q000235:genetics; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics*; D018402:Manduca / Q000235:genetics* / Q000254:growth & development / Q000276:immunology; D058977:Molecular Sequence Annotation; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D051192:Receptors, Pattern Recognition / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D019476:Insect Proteins; D051192:Receptors, Pattern Recognition
keywords: Genome annotation; Hemolymph proteins; Insect immunity; RNA-Seq; Transcriptome