A hepcidin-like gene (cmHep) was cloned and characterized from the liver of the blotched snakehead
Channa maculata. The complete cmHep cDNA was 756 bp in length, containing an open reading frame of
270 bp (encoding 89 amino acids), flanked by 210 bp and 276 bp of 50 and 30 untranslated regions, respectively.
The deduced peptide of 89 amino acids consisted of 24 aa, 40 aa and 25 aa for signal peptide, prodomain
and mature peptide, respectively. The mature peptide had eight cysteines at the identical conserved
positions incommonwithmost of otherknownhepcidins in vertebrates. cmHepcgene displayed a tripartite
structure (three exons interrupted by two introns), which organisation was conserved between the
blotched snakehead and other fish species. Phylogenetic analysis of hepcidins from C. maculata and other
vertebrates showed that major phylogenetic grouping of fish hepcidin coincided with the current euteleosts
classification, indicating the multiphyletic evolution of hepcidin in the teleosts. In the Acanthopterygii
subclade, there were two distinct additional subclades named as HAMP-Ac1 and HAMP-Ac2. The blotched
snakehead hepcidin was in the group HAMP-Ac1, which has the hypothetical iron regulatory sequence [Q-S/
I-H-L/I-S/A] motif in N-terminal of mature peptide. The RT-PCR showed cmHep mRNA transcripts were
widely distributed in all tissues tested in the blotched snakehead including the liver, gill, intestine, spleen,
head kidney and peripheral white blood cell. The most abundant of cmHep mRNA was detected in liver. A
significant up-regulation ofcmHepexpression wasdetected only in head kidney at24 hpost-challenge with
Vibrio parahaemolyticus in blotched snakehead adults, no significant differences found in liver, gill, intestine
and spleen. ThecmHep expression was up-regulated in spleen, head kidney and intestine at 24 h post-injection
with LPS in blotched snakehead juveniles, livercmHepexpression wasnot altered. Iron overloading and
poly I:C stimulation down-regulated cmHep expression in liver, but did not significantly change cmHep
expression in spleen, head kidney and intestine in blotched snakehead juveniles.