Molecular identification and expression analysis of a novel tumor necrosis factor receptor from the black rockfish, Sebastes schlegelii.

Members of the tumor necrosis factor (TNF) and TNF receptor (TNFR) superfamilies play crucial roles in both innate and adaptive immunity. In the present study, we isolated the full-length cDNA for black rockfish (Sebastes schlegelii) TNFR (BrTNFR). This cDNA is 2405 bp in length and contains a 939-bp open reading frame, a 27-bp 5' untranslated region, and a 1439-bp 3' untranslated region including a polyadenylation signal (AATAAA) and polyadenylation site. The 313-amino-acid predicted BrTNFR sequence is homologous to other TNFR sequences, contains four cysteine-rich domains and a death-effector domain (DED), and lacks a transmembrane region. Expression of BrTNFR mRNA was detected in eight different tissues from healthy black rockfish and was highest in peripheral blood lymphocytes and gills. In analyses of mitogen-stimulated BrTNFR expression in peripheral blood lymphocytes, expression of BrTNFR mRNA was observed between 1 and 24h after stimulation with lipopolysaccharide, concanavalin A/phorbol myristate acetate, or poly I:C. Although the data suggest that BrTNFR represents an ancestral member of the TNFR superfamily, the orthology of TNFR in teleost fish is difficult to establish because few TNFRs have been identified in these species.