title: A member of the Tlr family is involved in dsRNA innate immune response in Paracentrotus lividus sea urchin.
abstract: The innate immune response involves proteins such as the membrane receptors of the Toll-like family (TLRs), which trigger different intracellular signalling pathways that are dependent on specific stimulating molecules. In sea urchins, TLR proteins are encoded by members of a large multigenic family composed of 60-250 genes in different species. Here, we report a newly identified mRNA sequence encoding a TLR protein (referred to as Pl-Tlr) isolated from Paracentrotus lividus immune cells. The partial protein sequence contained the conserved Toll/IL-1 receptor (TIR) domain, the transmembrane domain and part of the leucine repeats. Phylogenetic analysis of the Pl-Tlr protein was accomplished by comparing its sequence with those of TLRs from different classes of vertebrates and invertebrates. This analysis was suggestive of an evolutionary path that most likely represented the course of millions of years, starting from simple organisms and extending to humans. Challenge of the sea urchin immune system with poly-I:C, a chemical compound that mimics dsRNA, caused time-dependent Pl-Tlr mRNA up-regulation that was detected by QPCR. In contrast, bacterial LPS injury did not affect Pl-Tlr transcription. The study of the Tlr genes in the sea urchin model system may provide new perspectives on the role of Tlrs in the invertebrate immune response and clues concerning their evolution in a changing world.
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare "Alberto Monroy", Via U. La Malfa 153, 90146 Palermo, Italy. Electronic address: roberta.russo@ibim.cnr.it.
authors.forename: Roberta
authors.initials: R
authors.lastname: Russo
authors.affiliation: Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche, Università degli Studi di Palermo, via Archirafi 20, Palermo, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Chiaramonte
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare "Alberto Monroy", Via U. La Malfa 153, 90146 Palermo, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Matranga
authors.affiliation: Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche, Università degli Studi di Palermo, via Archirafi 20, Palermo, Italy. Electronic address: vincenzo.arizza@unipa.it.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Arizza
mesh_terms: D000818:Animals; D005075:Biological Evolution; D007113:Immunity, Innate; D008070:Lipopolysaccharides / Q000276:immunology; D010802:Phylogeny; D011070:Poly I-C / Q000276:immunology*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012330:RNA, Double-Stranded / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017472:Receptors, Interleukin-1 / Q000235:genetics; D012617:Sea Urchins / Q000276:immunology*; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D008070:Lipopolysaccharides; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D051193:Toll-Like Receptors; D011070:Poly I-C
keywords: Evolution; Gene expression; Immune cells; Mediterranean sea urchin; Toll-like receptor