Molecular cloning and characterization of high mobility group box1 (Ls-HMGB1) from humphead snapper, Lutjanus sanguineus.

High mobility group box1 (HMGB1) is a kind of chromatin-associated nonhistone protein important for nucleosome formation, transcriptional regulation and inflammation. However, the reports about HMGB1 of marine fish were still limited. Here, we cloned and characterized a HMGB1 gene from humphead snapper, Lutjanus sanguineus (Ls-HMGB1). The Ls-HMGB1 cDNA composed of 1199 bp with a 70 bp of 5'-UTR, 630 bp open reading frame (ORF) and 499 bp 3'-UTR, encoded a polypeptide of 210 amino acids (GenBank Accession No: KJ783442). Sequence alignment of Ls-HMGB1 showed the highest similarity of 91% with Sciaenops ocellatus HMGB1 protein. Quantitative real-time PCR (qRT-PCR) analysis revealed that Ls-HMGB1 had relatively high expression level in skin, kidney and heart. After Vibrio harveyi and poly I:C stimulation, transcripts of Ls-HMGB1 were significantly increased and reached to peak at 18 h p.i. The L. sanguineus interleukin-6 (Ls-IL6) transcription in HK leukocytes was significantly induced by recombinant LsHMGB1 (rLsHMGB1). These results indicated that Ls-HMGB1 may play an important role in immune response of L. sanguineus during pathogen challenge.