Novel Functions of Interleukin-1 Beta in Spotted Halibut(Verasper variegatus) at Its Embryonic and Metamorphic Stages

摘要

Interleukin-1 beta(IL-1β) is a cytokine involved in the control of inflammatory responses.The functions of IL-1β have been extensively studied in many vertebrates.However,few studies focused on the functions of IL-1β in the spotted halibut(Verasper variegatus),an endangered aquatic fish that easily suffers from bacterial and viral infections.We first cloned and sequenced the IL-1β gene from V.variegatus(Vv IL-1β).Its conservative interleukin-1 propeptide and interleukin-1/18 domains corresponding regions,characteristics of the IL-1 protein family and TA-rich motifs relating to inflammatory responses were similar to those of the IL-1β genes from other teleost and mammals.The phylogenetic analysis showed that Vv IL-1β was homologous to the IL-1β gene of other vertebrates.Treatment with pathogen-associated molecular patterns(PAMPs) induced a significant and rapid up-regulation of Vv IL-1β expression in the peripheral blood leukocytes(PBLs),revealing that Vv IL-1β is actively involved in the host immune responses against bacterial and viral pathogens.The expression level of Vv IL-1β was relatively high in the PBLs,gill,and intestine,indicating the immunological function of Vv IL-1β.Vv IL-1β also had interesting expression patterns at specific developmental stages,implying that the IL-1β of flatfishes may have some novel functions during embryonic development and metamorphosis.The 3 D structure prediction also provided information about how Vv IL-1β interacts with its receptor protein.These results suggested that Vv IL-1β may have multiple functions in V.variegatus and provided us valuable information for understanding the novel functions of IL-1β.