Characterization and expression pattern of a novel β-defensin in common carp (Cyprinus carpio L.): implications for its role in mucosal immunity

Abstract

β-defensins are a group of cysteine-rich cationic antimicrobial peptides that play antibacterial and antiviral roles in immune systems of vertebrates. Here, we report the cloning and identification of a β-defensin 3 cDNA sequence from the common carp (Cyprinus carpio L.). Sequence alignment and phylogenetic analysis indicated that this β-defensin 3 belonged to the BD-2 group of fish. Real-time PCR showed that the β-defensin 3 mRNA was expressed in all the tissues of normal common carp that we examined and was highly expressed in the spleen and gills. When challenged with Vibrio anguillarum, the expression level of common carp β-defensin 3 mRNA was quickly upregulated in various tissues. Our results indicate that the β-defensin 3 showed markedly high constitutive expression in the gills, and significantly upregulated expression in the hindgut of the common carp after infection, suggesting it plays an important role in the innate and mucosal immunity of common carp.

Key words:

• β-defensin
• common carp (Cyprinus carpio L.)
• molecular cloning
• mRNA expression
• innate immunity

Acknowledgments

This work was supported by the University Independent Innovation Project of Jinan, Shandong, China [grant numbers 200715072 and 200906020].

Author contribution

Conceived and designed the experiments: Liguo An and Guiwen Yang. Performed the experiments: Hua Li, Hongyan Guo, Shijuan Shan, and Chenchen Qi. Analyzed the data: Hua Li, Hongyan Guo, Liguo An, and Guiwen Yang. Wrote the paper: Hua Li and Guiwen Yang.

Notes

Abbreviations: AMPs, antimicrobial peptides; BD, β-defensin; CFU, colony forming units; RT-PCR, reverse transcription-polymerase chain reaction; CDS, coding sequence.