Cloning, expression pattern, and potential role of p38 and p65 in response to lipopolysaccharide in yellow catfish ().

Mitogen-activated protein kinases (MAPK) and nuclear factor kappa B (NF-κB) pathways are considered to be two crucial intracellular signaling cascades in pro-inflammatory responses. In this study, we reported the coding sequences (CDS) of p38 and p65 from yellow catfish. We also investigated the gene structure, expression patterns and functional role in yellow catfish. The CDS of p38 is 1,086 bp encoding 361 amino acids (AA). The MAPKp38 protein has a long highly conserved serine/threonine protein kinases catalytic domain. The p65 CDS is 1,794 bp, and the gene encodes 597 AA, with a Rel homology domain (RHD) which consists of a RHD-DNA-binding domain and an Ig-like, plexins, transcription factors (IPT) domain. Moreover, MAPKp38 and NF-κBp65 protein of bony fish and other vertebrates have a single clade. Quantitative real-time PCR analysis revealed the presence of the p38 and p65 transcript in 12 tissues of healthy yellow catfish. The highest expression levels of p38 and p65 were detected in the heart and liver, respectively. Upon stimulation with an intraperitoneal injection of lipopolysaccharide (LPS), the expression levels of p38 and p65 were up-regulated in the intestine. These results indicated that p38 and p65 play important roles in mediating the response protection against LPS in yellow catfish.