title: Molecular and functional characterization of Toll-like receptor (Tlr)1 and Tlr2 in common carp (Cyprinus carpio).
abstract: Toll-like receptors (TLRs) are fundamental components of innate immunity that play significant roles in the defence against pathogen invasion. In this study, we present the molecular characterization of the full-length coding sequence of tlr1, tlr2a and tlr2b from common carp (Cyprinus carpio). Each is encoded within a single exon and contains a conserved number of leucine-rich repeats, a transmembrane region and an intracellular TIR domain for signalling. Indeed, sequence, phylogenetic and synteny analysis of carp tlr1, tlr2a and tlr2b support that these genes are orthologues of mammalian TLR1 and TLR2. The tlr genes are expressed in various immune organs and cell types. Furthermore, the carp sequences exhibited a good three-dimensional fit with the heterodimer structure of human TLR1-TLR2, including the potential to bind to the ligand Pam3CSK4. This supports the possible formation of carp Tlr1-Tlr2 heterodimers. However, we were unable to demonstrate Tlr1/Tlr2-mediated ligand binding in transfected cell lines through NF-κB activation, despite showing the expression and co-localization of Tlr1 and Tlr2. We discuss possible limitations when studying ligand-specific activation of NF-κB after expression of Tlr1 and/or Tlr2 in human but also fish cell lines and we propose alternative future strategies for studying ligand-binding properties of fish Tlrs.
authors.affiliation: Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: Inge R
authors.initials: IR
authors.lastname: Fink
authors.affiliation: Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: Danilo
authors.initials: D
authors.lastname: Pietretti
authors.affiliation: Department of Infectious Diseases and Immunology, Utrecht University, Yalelaan 1, 3584 CL, Utrecht, The Netherlands.
authors.forename: Carlos G P
authors.initials: CGP
authors.lastname: Voogdt
authors.affiliation: Laboratory of Biochemistry, Wageningen University, PO Box 8128, 6700 ET, Wageningen, The Netherlands.
authors.forename: Adrie H
authors.initials: AH
authors.lastname: Westphal
authors.affiliation: Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: Huub F J
authors.initials: HFJ
authors.lastname: Savelkoul
authors.affiliation: Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Forlenza
authors.affiliation: Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands. Electronic address: geert.wiegertjes@wur.nl.
authors.forename: Geert F
authors.initials: GF
authors.lastname: Wiegertjes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002347:Carps / Q000145:classification / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007113:Immunity, Innate; D010802:Phylogeny; D016415:Sequence Alignment; D026801:Synteny; D051194:Toll-Like Receptor 1 / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D051195:Toll-Like Receptor 2 / Q000737:chemistry / Q000235:genetics* / Q000276:immunology
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2
keywords: Heterodimer; Innate immunity; TLR signalling; Teleost; Toll-like receptor