title: Peptidoglycan recognition protein genes and their roles in the innate immune pathways of the red flour beetle, Tribolium castaneum.
abstract: We have previously demonstrated that the functional Toll and IMD innate immune pathways indeed exist in the model beetle, Tribolium castaneum while the beetle's pathways have broader specificity in terms of microbial activation than that of Drosophila. To elucidate the molecular basis of this broad microbial activation, we here focused on potential upstream sensors of the T. castaneum innate immune pathways, peptidoglycan recognition proteins (PGRPs). Our phenotype analyses utilizing RNA interference-based comprehensive gene knockdown followed by bacterial challenge suggested: PGRP-LA functions as a pivotal sensor of the IMD pathway for both Gram-negative and Gram-positive bacteria; PGRP-LC acts as an IMD pathway-associated sensor mainly for Gram-negative bacteria; PGRP-LE also has some roles in Gram-negative bacterial recognition of the IMD pathway. On the other hand, we did not obtain clear phenotype changes by gene knockdown of short-type PGRP genes, probably because of highly inducible nature of these genes. Our results may collectively account for the promiscuous bacterial activation of the T. castaneum innate immune pathways at least in part.
authors.affiliation: Applied Entomology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Koyama
authors.affiliation: Applied Entomology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Kato
authors.affiliation: Applied Entomology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Chieka
authors.initials: C
authors.lastname: Minakuchi
authors.affiliation: Applied Entomology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Applied Entomology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Kakeru
authors.initials: K
authors.lastname: Yokoi
authors.affiliation: Applied Entomology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan. Electronic address: k-miura@agr.nagoya-u.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Miura
mesh_terms: D000818:Animals; D001412:Bacillus subtilis / Q000472:pathogenicity; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D060467:Disease Resistance / Q000235:genetics; D016972:Enterobacter cloacae / Q000472:pathogenicity; D004926:Escherichia coli / Q000472:pathogenicity; D055785:Gene Knockdown Techniques; D017344:Genes, Insect; D007113:Immunity, Innate / Q000235:genetics*; D016982:Micrococcus luteus / Q000472:pathogenicity; D010802:Phylogeny; D034622:RNA Interference; D014231:Tribolium / Q000235:genetics / Q000276:immunology* / Q000382:microbiology
chemical_list: D002352:Carrier Proteins; C118897:peptidoglycan recognition protein
keywords: Innate immunity; Peptidoglycan recognition protein genes; RNA interference; Tribolium castaneum