Molecular cloning and mRNA expression of a hepcidin gene from the spinyhead croaker, Collichthys lucidus

Antimicrobial peptides are important components that participate in host innate immune activities and play crucial roles in host defense against microbial invasion. Hepcidin is an antimicrobial peptide and iron-regulatory molecule that primarily functions in the liver. In the present study, we first obtained a full-length cDNA sequence of hepcidin and its corresponding genomic DNA sequence from Collichthys lucidus using RT-PCR and rapid amplification of cDNA ends (RACE), and then analyzed these sequences using bioinformatics software. The results showed that C. lucidus hepcidin (CL-hepc) possesses two introns and three exons in the genomic DNA, with a length of 816 bp. The open reading frame was 264 bp, encoding an 87 amino acid peptide, and with high similarity (88.89%) to 83416593 Larimichthys crocea (ABC18307) and relatively low similarity (47.73%) to 158358729 L. crocea (ABY84845.1). The pre-peptide contained a signal peptide (28 amino acids), a prodomain (34 amino acids), and a mature peptide (25 amino acids). The predicted 25 amino acid hepcidin mature peptide included 8 conserved cysteine residues. Quantitative real-time reverse transcription-PCR analysis revealed specific expression patterns of CL-hepc, with the highest expression observed in the liver, relatively low expression observed in the gill and spleen, and almost no expression detected in other tissues analyzed. In conclusion, we identified a hepcidin from C. lucidus that has common expression patterns with other hepcidins. However, as this hepcidin is inconsistent with two other hepcidins from L. crocea in terms of the phylogenetic tree, the presence of another hepcidin gene warrants further investigation.