Involvement of AmphiREL, a Rel-like gene identified in Brachiastoma belcheri, in LPS-induced response: Implication for evolution of Rel subfamily genes

Rel/NF-κB family genes are important transcriptional factors regulating vital activities of immunity response, but no Rel/NF-κB gene has been identified in amphioxus. In this study, we have not only identified and characterized a Rel-like gene from Brachiastoma belcheri, but also extensively studied the evolution of Rel gene subfamily. We found that: 1) the amphioxus genome contains an AmphiREL gene encoding a Rel/NF-κB homolog, and AmphiREL gene was involved in the innate immune response of LPS stimulation in amphioxus. 2) Gene synteny comparison and structure comparison suggested that AmphiREL is an orthologous gene of human RELB, and is a paralogous gene of human RELA and REL. 3) Structural changes of Rel subfamily proteins are diverse during the evolution process, and imply their functional diversity. 4) The Rel subfamily genes have undergone very strong purifying selection. Together, our results provide important clues for understanding the evolution and function of Rel subfamily genes.

► AmphiRel gene was involved in the innate immune response.
► AmphiRel gene is an ancestor gene of vertebrate Rel subfamily.
► Structure of Rel subfamily proteins has diversified during the evolution process.
► The Rel subfamily genes have undergone very strong purifying selection.