Insights into the diversity of NOD-like receptors: Identification and expression analysis of NLRC3, NLRC5 and NLRX1 in rainbow trout

Nucleotide‐binding and oligomerization domain (NOD)‐like receptors in teleost fish: Current knowledge and future perspectives

“…Using the tBLASTn program, analysis of the turbot transcriptome database revealed the presence of two NLR‐C3 splice variants, NLR‐C3a and NLR‐C3b (Gao et al., ; Hou et al., ). Recently, NLR‐C3, NLR‐C5 and NLR‐X1 were found in both Miiuy croaker ( Miichthys miiuy ) (Li, Kong, Gao, Wu, & Xu, ) and rainbow trout ( Oncorhynchus mykiss ) (Álvarez et al., ); the full‐length cDNA sequences and organization of these three genes have been identified and characterized (Álvarez et al., ; Li et al., ). Strikingly, only NLR‐C5 lacked the CARD domain and contained fewer LRR domains at the C‐terminal region when compared to the other two rainbow trout ( Oncorhynchus mykiss ) NLRs (Álvarez et al., ).…”

“…Recently, NLR‐C3, NLR‐C5 and NLR‐X1 were found in both Miiuy croaker ( Miichthys miiuy ) (Li, Kong, Gao, Wu, & Xu, ) and rainbow trout ( Oncorhynchus mykiss ) (Álvarez et al., ); the full‐length cDNA sequences and organization of these three genes have been identified and characterized (Álvarez et al., ; Li et al., ). Strikingly, only NLR‐C5 lacked the CARD domain and contained fewer LRR domains at the C‐terminal region when compared to the other two rainbow trout ( Oncorhynchus mykiss ) NLRs (Álvarez et al., ). In Japanese flounder ( Paralichthys olivaceus ), NOD1 gene was determined by BLAST sequencing method (Park et al., ).…”

“…(Xie et al., ), but different than the response observed in humans (Moore et al., ), suggesting that the NLR‐X1 may play a different role in piscine and mammalian immunity. In cells from a rainbow trout ( Oncorhynchus mykiss ) gill epithelial cell line, RTgill‐W1, treatment with different PAMPs induced expression of NLR‐C3, NLR‐C5 and NLR‐X1 increased in response to Poly(I:C) or LPS challenge (Álvarez et al., ).…”

“…In RTgill‐W1 cells, stimulation with LPS or Poly(I:C) increased the expression of TNF‐α, IL‐1β, NLR‐C3, NLR‐C5 and NLR‐X1. However, while exposure to TNF‐α or IL‐1β resulted in an increase in NLR‐C3 expression, NLR‐C5 and NLR‐X1 expression remained unchanged (Álvarez et al., ). Recent studies show that NLR‐C5 is a potent negative regulator of NF‐κB and type I IFN signalling pathways in mammals (Benko, Magalhaes, Philpott, & Girardin, ; Cui et al., ).…”

“…In mammals, NRL‐C3 has emerged as a negative regulator of innate immune signalling by interfering in TLR or STING signalling pathways (Schneider et al., ; Zhang et al., ). Both rainbow trout ( Oncorhynchus mykiss ) (Álvarez et al., ) and zebrafish ( Danio rerio ) (Shiau, Monk, Joo, & Talbot, ) NLR‐C3 have also been reported to negatively regulate inflammation and macrophage activation. However, other studies suggest that NLR‐C3 may not have a negative regulatory function in a subset of teleost fish, where it functions as a PRR in pathogen recognition (Paria et al., ; Unajak et al., ).…”