Molecular characterization and immune functional analysis of IRF2 in common carp (Cyprinus carpio L.): different regulatory role in the IFN and NF-\u03baB signalling pathway

Hua Li,Rongrong Liu,Liguo An,Guiwen Yang,Xinping Chen,Fumiao Zhang,Shijuan Shan,Linlin Zheng,Yaoyao Zhu

doi:10.1186/s12917-021-03012-7

Hua Li, Rongrong Liu + Show 7 more

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https://doi.org/10.1186/s12917-021-03012-7

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Abstract

BackgroundInterferon regulatory factor 2 (IRF2) is an important transcription factor, which can regulate the IFN response and plays a role in antiviral innate immunity in teleost.ResultsIn the present study, the full-length cDNA sequence of IRF2 (CcIRF2) was characterized in common carp (Cyprinus carpio L.), which encoded a protein containing a conserved DNA-binding domain (DBD) and an IRF-associated domain (IAD). Phylogenetic analysis showed that CcIRF2 was most closely related with IRF2 of Ctenopharyngodon idella. CcIRF2 transcripts were detectable in all examined tissues, with higher expression in the gills, spleen and brain. CcIRF2 expression was upregulated in immune-related tissues of common carp upon polyinosinic:polycytidylic acid (poly (I:C)) and Aeromonas hydrophila stimulation and induced by poly (I:C), lipopolysaccharide (LPS), peptidoglycan (PGN) and flagellin in the peripheral blood leucocytes (PBLs) and head kidney leukocytes (HKLs). In addition, overexpression of CcIRF2 decreased the expression of IFN and IFN-stimulated genes (ISGs), and a dual-luciferase reporter assay revealed that CcIRF2 could increase the activation of NF-κB.ConclusionsThese results indicate that CcIRF2 participates in antiviral and antibacterial immune response and negatively regulates the IFN response, which provide a new insight into the regulation of IFN system in common carp, and are helpful for the prevention and control of infectious diseases in carp farming.

Highlights

Interferon regulatory factor 2 (IRF2) is an important transcription factor, which can regulate the IFN response and plays a role in antiviral innate immunity in teleost
Multiple sequence alignment revealed that IRF2 amino acids sequences were conserved in all vertebrates, and significant homology was found in DNA-binding domain (DBD) (Fig. 1)
The phylogenetic tree including IRF2 sequences from all known species was constructed using the neighbourjoining method, which was divided into multiple branches, and cDNA sequence of IRF2 (CcIRF2) was most closely related with IRF2 of C. idella (Fig. 2)

Summary

Introduction

Interferon regulatory factor 2 (IRF2) is an important transcription factor, which can regulate the IFN response and plays a role in antiviral innate immunity in teleost. Interferon (IFN) regulatory factors (IRFs) are key transcription factors in vertebrates and invertebrates, which regulate the expression of IFNs and IFN-stimulated genes (ISGs), and perform diverse biological functions in. The expression of IRF2 can be upregulated by viral [5,6,7,8, 10, 12,13,14, 16] or bacterial [5, 10, 15] stimulation in different fish tissues, suggesting that IRF2 plays a role in host antiviral and antibacterial responses. The IFN response is crucial to the antiviral innate immunity of teleost, which can be regulated by IRF2 in different ways. In large yellow croaker, IRF2 was found to induce IFNd and IFNh promoter activity but inhibit IFNc promoter activity [19]

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