title: Molecular characterization of nucleotide binding and oligomerization domain (NOD)-2, analysis of its inductive expression and down-stream signaling following ligands exposure and bacterial infection in rohu (Labeo rohita).
abstract: Nucleotide-binding and oligomerization domain (NOD)-2 is a cytoplasmic pattern recognition receptor (PRR) and is a member of NOD like receptor (NLR) family. It senses a wide range of bacteria and viruses or their products and is involved in innate immune responses. In this report, NOD-2 gene was cloned and characterized from rohu (Labeo rohita) which is highly commercially important fish species in the Indian subcontinent. The full length rohu NOD-2 (rNOD-2) cDNA comprised of 3176 bp with a single open reading frame (ORF) of 2949 bp encoding a polypeptide of 982 amino acids (aa) with an estimated molecular mass of 109.65 kDa. The rNOD-2 comprised two N-terminal CARD domains (at 4-91 aa and 111-200 aa), one NACHT domain (at 271-441 aa) and seven C-terminal leucine rich repeat (LRR) regions. Phylogenetically, rNOD-2 was closely related to grass carp NOD-2 (gcNOD2) and exhibited significant similarity (94.2%) and identity (88.6%) in their amino acids. Ontogeny analysis of rNOD-2 showed its constitutive expression across the developmental stages, and highlighted the embryonic innate defense system in fish. Tissue specific analysis of rNOD-2 by quantitative real-time PCR (qRT-PCR) revealed its wide distribution; highest expression was in liver followed by blood. In response to PGN and LTA stimulation, Aeromonas hydrophila and Edwardsiella tarda infection, and poly I:C treatment, expression of rNOD-2 and its associated downstream molecules RICK and IFN-γ were significantly enhanced in the treated fish compared to control. These findings suggested the key role of NOD-2 in augmenting innate immunity in fish in response to bacterial and viral infection. This study may be helpful for the development of preventive measures against infectious diseases in fish.
authors.affiliation: Fish Health Management Division, Central Institute of Freshwater Aquaculture (CIFA), Kausalyaganga, Bhubaneswar, Orissa 751002, India.
authors.forename: B
authors.initials: B
authors.lastname: Swain
authors.forename: M
authors.initials: M
authors.lastname: Basu
authors.forename: B R
authors.initials: BR
authors.lastname: Sahoo
authors.forename: N K
authors.initials: NK
authors.lastname: Maiti
authors.forename: P
authors.initials: P
authors.lastname: Routray
authors.forename: A E
authors.initials: AE
authors.lastname: Eknath
authors.forename: M
authors.initials: M
authors.lastname: Samanta
mesh_terms: D016980:Aeromonas hydrophila / Q000276:immunology* / Q000472:pathogenicity; D000595:Amino Acid Sequence; D000818:Animals; D002347:Carps; D002478:Cells, Cultured; D003001:Cloning, Molecular; D020609:Edwardsiella tarda / Q000276:immunology* / Q000472:pathogenicity; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000276:immunology; D016905:Gram-Negative Bacterial Infections / Q000276:immunology*; D007113:Immunity, Innate; D008024:Ligands; D008969:Molecular Sequence Data; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D010802:Phylogeny; D015398:Signal Transduction / Q000276:immunology
chemical_list: D029941:Fish Proteins; D008024:Ligands; D053473:Nod2 Signaling Adaptor Protein