Identification and characterization of a putative lipopolysaccharide-induced TNF-α factor (LITAF) gene from Amphioxus (Branchiostoma belcheri): An insight into the innate immunity of Amphioxus and the evolution of LITAF

Innate immunity defenses against infectious agent in all multicultural organisms. TNF-alpha is an important cytokine that can be stimulated by Lipopolysaccharide (LPS) to regulate the innate immunity. The lipopolysaccharide-induced TNF-a factor (LITAF) functions as a transcription factor for regulating the expression of TNF-a as well as various inflammatory cy:okines in response to LPS stimulation. The physiological significance of LITAF gene in the innate immunity of various animals has recently been reported. However, no LITAFgene has yet been identified in amphioxus, which is the best available stand-in for the proximate invertebrate ancestor of the vertebrates. In this study, we identified and characterized an amphioxus LITAFgene (designated as AmphiLITAF). First, we identified the AmphiLITAF from the amphioxus and found that AmphiLITAF gene with similar to 1.6 kb in length has a 827 bp cDNA transcription product which encodes a putative protein with 127 amino acids containing conserved LITAF-domain, and the deduced amino acid of AmphiLITAF shared 37-60% similarity with the LITAFs from other species: second, we uncovered the spatial distribution of the LITAF in different tissues, the expression level of AmphiLITAF mRNA was the highest in hepatic cecum and intestine, moderate in muscles, gills and gonad, and the lowest in notochord. Our findings provide an insight into the innate immune response in the amphioxus and the evolution of the LITAF family. (C) 2012 Elsevier Ltd. All rights reserved.