Structural insights of rohu TLR3, its binding site analysis with fish reovirus dsRNA, poly I:C and zebrafish TRIF

► Structural domain analysis of TLR3 in rohu fish (Labeo rohita) and 3D modeling of its ectodomain (TLR3-ECD) and Toll/IL-1 (TIR) domain. ► Molecular docking of poly I:C and dsRNA of glycoprotein gene of three important aquatic infectious reovirus with the rohu TLR3-ECD. ► Prediction of LRR (4–6), (13–14) and (20–22) as the essential domains of poly I:C recognition in rohu TLR3. ► In rohu TLR3, LRR (8–15) and (17–24) are the key domains to recognize the dsRNA of aquatic reoviruses. ► 3D modeling of zebrafish TRIF (TIR-domain-containing adapter-inducing interferon-β) and prediction of key amino acids that interact with rohu TLR3-TIR. In response to double stranded RNA (dsRNA) viruses, toll-like receptor 3 (TLR3) in fish activates signaling like human, and induces innate immunity. This suggested the existence of dsRNA binding domains in fish TLR3 as reported in higher vertebrates. In in silico analysis, leucine rich repeat (LRR) regions (4–6, 13–14, 20–22), and LRR (8–15, 17–24) were identified as key domains in rohu TLR3 as poly I:C and dsRNA of fish reovirus (AGCRV,VHSV and IHNV) binding regions. 3D-models of rohu TLR3-TIR and zebrafish TRIF were generated by homology and ab initio modeling respectively, and their interacting domains were predicted. This is the first report of TLR3 modeling in fish.