title: Catfish hepcidin gene is expressed in a wide range of tissues and exhibits tissue-specific upregulation after bacterial infection.
abstract: Antimicrobial peptides (AMPs) are important components of the host innate immune response against microbial invasion. The cysteine-rich AMPs such as defensin and hepcidin have been extensively studied from various organisms, but their role in disease defense in catfish is unknown. As a first step, we sequenced a hepcidin cDNA from both channel catfish and blue catfish, and characterized the channel catfish hepcidin gene. The channel catfish hepcidin gene consists of two introns and three exons that encode a peptide of 96 amino acids. The amino acid sequences and gene organization were conserved between catfish and other organisms. In contrast to its almost exclusive expression in the liver in humans, the channel catfish hepcidin gene was expressed in a wide range of tissues except brain. Its expression was detected early during embryonic and larval development, and induced after bacterial infection with Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish (ESC) in a tissue-specific manner. The upregulation was observed in the spleen and head kidney, but not in the liver. The expression of hepcidin was upregulated 1--3 days after challenge, but returned to normal levels at 7 days after challenge. The expression profile of the catfish hepcidin gene during the course of bacterial infection mirrors those of inflammatory proteins such as chemokines, suggesting an important role for hepcidin during inflammatory responses.
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, AL 36849, USA.
authors.forename: Baolong
authors.initials: B
authors.lastname: Bao
authors.forename: Eric
authors.initials: E
authors.lastname: Peatman
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Chongbo
authors.initials: C
authors.lastname: He
authors.forename: Zhanjiang
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics*; D001483:Base Sequence; D002397:Catfishes / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D018076:DNA, Complementary / Q000235:genetics; D020610:Edwardsiella ictaluri; D004756:Enterobacteriaceae Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary*; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology*; D064451:Hepcidins; D006801:Humans; D007059:Ictaluridae / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D009928:Organ Specificity; D018805:Sepsis / Q000235:genetics / Q000276:immunology / Q000662:veterinary; D013045:Species Specificity; D015854:Up-Regulation
chemical_list: D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; C578702:HAMP protein, human; D064451:Hepcidins