Molecular cloning and expression analysis of interleukin-1β from Japanese sea perch (Lateolabrax japonicus)

The technology of homology cloning and anchored PCR was used to clone the IL-1 β gene from the Japanese sea perch (Lateolabrax japonicus).The full-length cDNA of sea perch IL-1β was 1 310 bp,including a 5' untranslated region (UTR) of 136 bp,a 3' UTR of 430 bp,and an ORF of 774 bp encoding a polypeptide of 258 amino acids with an estimated molecular mass of 29.31 kDa.The searches for nucleotides and protein sequence similarities with the BLAST analysis indicated that the deduced amino acid sequence of sea perch IL-1 β was homological to the IL-1 β in other fish species and even the mammalian.Conserved signature sequences of the IL-1 β gene family were found in the sea perch IL-1β deduced amino acid sequence.Temporal expressions of the IL-1β gene in LPS or iridovirus challenged group and in control group were measured by the semi-quantitative RT-PCR.The mRNA transcripts of IL-1β could be detected in head-kidney,spleen,liver,gill and heart of the healthy individuals,and the expression level of IL-1 β in head-kidney,spleen and gill was higher than that in liver and heart,but it was hard to be detected in the brain.After being stimulated by the LPS or iridovirus,the IL-1 β expression in most of examined tissues was up-regulated,and also could be detected in the brain.These results indicated that the expression of sea perch IL-1 β was constitutive and could be up-regulated by immune effector stimulation.Therefore the sea perch IL-1 β could play a critical role in the host-pathogen interaction.