Molecular characterization and expression of TLR7 and TLR8 in barbel chub (Squaliobarbus curriculus): Responses to stimulation of grass carp reovirus and lipopolysaccharide.

摘要: The barbel chub (Squaliobarbus curriculus) is a kind of small size commercial fish species that widely spread in Asia and has shown significant resistance to disease. In this study, the full-length cDNA sequences Toll-like receptor (TLR) 7 8 from S. curriculus, designated as ScTLR7 ScTLR8, were cloned, their differences structure responses grass carp (GCRV) infection lipopolysaccharide stimulation investigated. 3715 base pair (bp) contained complete open reading frame 3162 bp encoded putative polypeptide 1053 amino acid residues. 4624 ScTLR8 3072 1023 consisted N-terminal signal peptide, leucine-rich repeats (LRRs), Toll/IL-1 Receptors domain. LRR motifs bend into horseshoe-like solenoid structure, while number LRRs between two genes different. Phylogenetic analysis showed both closely clustered with Ctenopharyngodon idellus Megalobrama amblycephala. Quantitative real-time polymerase chain reaction expression levels curriculus most abundant brain followed by spleen heart, lowest intestine. highest level was observed liver. After LPS stimulation, relative exhibited an overall trend up-regulation. type I-IFN down-regulation at time points 12, 24, 72 168 h compared 6 h after stimulation. Compared post GCRV infection, transcription up-regulated 12 168 h, MyD88, firstly 72 h, then down-regulated 168 h. Correlation significantly positively correlated MyD88 (Pearson correlation coefficient: 0.909, P: 0.033), positive also I IFN 0.962, 0.009), These results indicate may play important roles trigger different downstream immune pathways.