Interleukin-1β isolated from a marine fish reveals up-regulated expression in macrophages following activation with lipopolysaccharide and lymphokines

Abstract

The gilthead seabream IL-1β gene consists of five exons/four introns. The complete coding sequence contains a 102 bp 5’ untraslated region (UTR), a single open reading frame of a 762 bp which translates into a 253 amino acid molecule, and a 407 bp 3’UTR with a polyadenilation signal 14 nucleotides upstream of the poly(A)tail. The seabream sequence has highest degree of nucleotide (61.7%) and amino acid (53%) identity with the trout IL-1β sequences. The IL-1β message was detected by RT-PCR in head-kidney, blood, spleen, liver, gill and peritoneal exudate of both non-infected and Vibrio anguillarum-challenged fish. More importantly, IL-1β was highly expressed by purified macrophage monolayers and was up-regulated by lipopolysaccharide and lymphocyte-derived macrophage-activating factor stimulation.