Identification and molecular characterization of an Akirin2 homolog in Chinese loach (Paramisgurnus dabryanus)

• PdAkirin2 was expressed in a wide range of loach tissues and transcriptionally induced by bacterial infection.
• Strict nuclear localization of PdAkirin2 was experimentally confirmed.
• PdAkirin2 was up-regulated in response to challenges of Aeromonas hydrophila NJ-1, LPS and poly I:C.
• PdAkirin2 overexpression in vitro had significant effects on the expression of cytokines and NF-κB.

Akirin is a nuclear factor involved in innate immune responses of arthropods and mammals. In this study we have cloned an Akirin2 gene, pdakirin2, from freshwater Chinese loach (Paramisgurnus dabryanus) and characterized its biological functions. Phylogenetic analysis revealed deduced PdAkirin2 had high sequence identities to Akirin2 homologs from fish and mammals (70−91%), it contained two conserved nuclear localization signals (NLSs) with verified sub-cellular localization. Quantitative real-time (qRT)-PCR analysis indicated that PdAkirin2 was present in a wide range of loach tissues and showed up-regulation with challenges of Aeromonas hydrophila NJ-1, LPS and poly I:C. PdAkirin2 as an immune factor had significant effects on the expression of cytokines (TNFα, IFN-α, IFN-γ, IL-4 and IL-1β) and transcription factor NF-κB. This study provides insights into the potential role of PdAkirin2 in the innate immune system.