Molecular cloning, expression and functional analysis of NF-kB1 p105 from sea cucumber Holothuria leucospilota

The nuclear factor-κB (NF-κB) family is evolutionary conserved and plays key roles in the regulation of numerous basic cellular processes. In this study, a sea cucumber Holothuria leucospilota NF-κB1 p105 named HLp105 was first obtained. The full-length cDNA of HLp105 is 6564 bp long, with a 219 bp 5' untranslated region (UTR), a 2979 bp 3' UTR, and a 3366 bp open reading frame (ORF) encoding for 1121 amino acids with a deduced molecular weight of 123.92 kDa and an estimated pI of 5.31. HLp105 protein contains the conserved domain RHD, IPT, ANK and DEATH. HLp105 mRNA can be detected in all tissues examined, with the highest level in the intestine, followed by the transverse vessel, rete mirabile, coelomocytes, respiratory tree, bolishiti, cuvierian tubules, body wall, oesophagus and muscle. Challenged by LPS or poly (I:C), the transcription level of HLp105 was apparently up-regulated in the tissues examined. Besides, Over-expression of HLp105 in HEK293T cells, the apoptosis was inhibited, and the cytokines IL-1β and TNF-α were activated. The results are important for better understanding the function of NF-κB1 p105 in sea cucumber and reveal its involvement in immunoreaction.