NOD-like receptors (NLRs) are a family of cytoplasmic
pattern recognition receptors (
PRRs), of which NOD1 and NOD2, are the main representative members. Many investigations have focused on the role of NOD1 and NOD2 in the innate immune response in Cypriniformes and Siluriformes. As an important economic fish in Perciformes, little is known about the function of NOD1 and NOD2 in mandarinfish (Siniperca chuatsi).
RESULTS: The full-length NOD1 and NOD2
cDNA sequence was obtained using reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of
cDNA ends (RACE). The mandarinfish NOD1 and NOD2
cDNA sequences contain 3247 bp and 3257 bp, and encode 918
amino acids and 988
amino acids, respectively. Multiple sequence alignments showed that mNOD1 and mNOD2 share high similarity with that from other vertebrates. RT-PCR analysis revealed that relatively high levels of mNOD1 and mNOD2
mRNA were detected in gill and head kidney tissues, compared with the heart, spleen, liver, muscle, and intestine. In addition, the relative levels of mNOD1 and mNOD2 transcripts were significantly upregulated in three tissues when the fishes were challenged with LPS and
Poly I:C, interestingly, the NOD1
mRNA got peaked earlier than NOD2 after LPS induction in the spleen, gill, and head kidney, and during
Poly I:C treatment, the NOD2
mRNA got peaked at 8 h in spleen and gill, while NOD1 showed significant higher expression at 24 h post
infection, besides, in head kidney, the NOD2
mRNA showed a great increasing trend and NOD1 got peaked at 16 h. Therefore the mNOD1 and mNOD2 may act differently within different tissues in different time during
antiviral and antibacterial defense.
CONCLUSIONS: