Genomic organization and tissue-specific expression of hepcidin in the pacific mutton hamlet, Alphestes immaculatus (Breder, 1936).
Hepcidin is a cysteine-rich peptide involved in iron metabolism, inflammatory response and as antimicrobial peptide. Despite the fact that hepcidins have been identified in several fish species, only few have been completely characterized. This study, described the identification and complete molecular characterization of the hepcidin antimicrobial peptide 1 (HAMP1) gene of Alphestes immaculatus. Moreover, its specific expression level at both basal and lipopolysaccharide (LPS)-induced conditions in different tissues was also determined by real-time PCR. Results showed that the HAMP1gene consists of three exons and two introns encoding a preprohepcidin composed of 90 aa (24 aa for signal peptide, 40 aa for prodomain and 26 aa for mature peptide). The promoter region analysis revealed a TATA box sequence and several putative transcription factor binding sites. A comparative analysis showed CEBPα, CEBPβ, NF-kB, HNF3, GATA-1 and c-Rel as the most common found in fishes. The mature peptide possesses a pI of 8.34, which is the average among fish hepcidin. In addition, the structural modeling showed a hairpin structure with four putative disulfide bonds. A phylogenetic analysis revealed that this hepcidin gene is a HAMP1 class, and is clustered into the same group with the Serranid fish Epinephelus moara and the Antarctic fish Lycodichthys dearborni. Finally, the relative expression levels showed high basal values in liver and muscle, whereas in LPS-induced fish the relative expression tendency changed, with the highest values in spleen and head kidney tissues. This study describes the completely characterized HAMP1 gene of A. immaculatus and their patterns of expression level at different conditions and in different tissues, showing by first time muscle hepcidin expression could be relevant in the immune response in fish.
Unidad de Patologia Marina, Centro de Investigaciones Biologicas del Noroeste (CIBNOR), Mar Bermejo 195, Col, Playa Palo de Santa Rita, La Paz, BCS 23090, Mexico.
Jorge
J
Masso-Silva
Gill
G
Diamond
Maria
M
Macias-Rodriguez
Felipe
F
Ascencio
D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001492:Bass / Q000235:genetics*; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D040461:Gene Components; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D060226:Head Kidney / Q000378:metabolism; D064451:Hepcidins; D008070:Lipopolysaccharides; D008099:Liver / Q000378:metabolism; D008800:Mexico; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013154:Spleen / Q000378:metabolism
D023181:Antimicrobial Cationic Peptides; D017931:DNA Primers; D064451:Hepcidins; D008070:Lipopolysaccharides