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

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.