title: A toll-like receptor 3 homologue that is up-regulated by poly I:C and DNA virus in turbot Scophthalmus maximus.
abstract: In this study, the gene and promoter sequences of turbot Scophthalmus maximus (Sm) toll-like receptor 3 (Tlr3) were cloned and its mRNA tissue distribution and gene expression in response to polyinosinic:polycytidylic acid (poly I:C) and turbot reddish body iridovirus (TRBIV) challenges were studied in vivo. The smtlr3 gene spans over 4·4 kb with a structure of five exons-four introns and encodes a peptide of 916 amino acids. The putative protein shares the highest sequence identity of 52·8-78·5% with fish Tlr3 and contains a signal peptide sequence, 13 leucine-rich repeat (LRR) motifs, a transmembrane region and a toll/interleukin-1 receptor (TIR) domain. Phylogenetic analysis grouped it with other teleost Tlr3s. A number of transcription factor binding sites were identified in the 1538 bp 5' flanking region of smtlr3, including interferon-stimulated response element (ISRE) and those for interferon regulatory factors (IRF) and signal transducer and activator of transcriptions (STATs) smtlr3 transcripts were expressed ubiquitously with higher levels in the head kidney, heart and digestion organs. They were up-regulated by both poly I:C and TRBIV in immune and non-immune organs, but most strongly in the head kidney. Finally, the smtlr3 exhibited a two-wave induced expression during a five day time course when exposure of S. maximus to poly I:C. These findings provide insights into the role of SmTlr3 in antiviral response.
authors: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.|Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
authors: G-B
authors: GB
authors: Hu
authors: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors: X-P
authors: XP
authors: Li
authors: First Institute of Oceanography, State Oceanic Administration of China, Qingdao 266061, China.
authors: D-H
authors: DH
authors: Liu
authors: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors: Q-M
authors: QM
authors: Liu
authors: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.|Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
authors: S-C
authors: SC
authors: Zhang
keywords: Tlr3 signalling; antiviral response; gene expression; promoter characteristics; scophthalmid