| Visfatin was a newly identified adipocytokine and drew much attention for it could mimic insulin and phosphorylate insulin receptor (IR), insulin receptor substrate-1(IRS-1) and IRS-2to activate the insulin signal pathway. Moreover, as same as a cytokine, pre-B cell colony-enhancing factor (PBEF), and as an enzyme named nicotinamide phosphoribosyltransferase (Nampt), visfatin also became to be a proinflammatory or inflammatory cytokine and a rate-limting enzyme involved in NAD biosynthesis, which made visfatin could maintain the normal embryo development, protect cells against nutrition restriction and stress, inhibit macrophage, neutrophil and amnion endothelial cells from apoptosis and so on. Almost present researches put their emphases on human or murine visfatin, and little was about teleosts. So in this study, we aimed to clone four freshwater fishes (including silver Prussian carp, silver loweye carp, grass carp and bluntsnout bream) visfatin cDNA sequences, analyze their genomic organizations and detect their tissue distributions, with the hope of enriching the study of visfatin, contributing a better understanding of the molecular evolution of visfatin family in both lower vertebrate and mammals as a whole, and providing useful information for further investigations on visfatin's roles in teleost fish. The results in this research were as follow:(1) The silver Prussian carp (Carassius auratus gibelio) visfatin cDNA cloned from the liver was～2.0Kb long, contained a1482bp open reading frame (ORF), which encoded a protein of493amino acids, and there was a typical polyadenylation signal sequence (AATAAA) in3'-untranslated region (3'-UTR). Silver Prussian carp visfatin protein had six cysteine residues which could help to form disulfide bonds, three N-glycosylation sites and one tyrosine sulfation site. However, there was no signal peptide in silver Prussian carp visfatin. Furthermore, the complete gene was isolated from fin ray total genomic DNA. The whole gene was～10.0Kb and consisted of11exons and9introns. Although there was no non-coding sequence inserted between Exon4and5, the nucleotides GT and AG were existed at the boundary of Exon4and5, so it was thought that there were eleven exons in silver Prussian carp visfatin gene. Meanwhile, there were two different variants in Intron VI, and they shared highly homology only at the end of the forty nucleotides. The results of tissue distribution analysis revealed that silver Prussian carp visfatin mRNA was broadly expressed in brain, gill, liver, spleen, head kidney, intestine, muscle, mesenteric adipose and ovary, and levels were higher in gill, heart, ovary and mesenteric adipose.(2) The silver loweye carp (Hypophthalmichthys molitrix) visfatin cDNA cloned from the liver was～1.7Kb long and contained a1482bp ORF, which encoded a protein of493amino acids. Silver loweye carp visfatin protein had six cysteine residues, two N-glycosylation sites, one less than silver Prussian carp visfatin, and one tyrosine sulfation site. However, there was also no signal peptide in silver loweye carp visfatin. Furthermore, the complete gene was isolated from fin ray total genomic DNA. The whole gene was～4.5Kb and comprised of9exons and7introns. Although there was no intron sequence between Exon1and2, the nucleotides GT and AG were existed at the boundary of Exon1and2, so it was thought that there were nine exons in silver loweye carp visfatin gene. Silver loweye carp visfatin mRNA was broadly expressed in brain, gill, liver, spleen, head kidney, intestine, muscle, mesenteric adipose and testis.(3) The grass carp (Ctenopharyngodon idellus) visfatin cDNA cloned from the liver was～1.5Kb long and contained a1482bp ORF, which encoded a protein of493amino acids. Like the silver loweye carp visfatin, grass carp visfatin protein had six cysteine residues, two N-glycosylation sites and one tyrosine sulfation site. However, grass carp visfatin protein didn't have a signal peptide sequence either. Furthermore, the complete gene was isolated from fin ray total genomic DNA. The whole gene was～3.6Kb and comprised of10exons and7introns. Though there were no intron sequences inserted between Exon1and2or Exon3and4, the nucleotides GT and AG were existed at the boundary of Exon1and2, Exon3and4, so it was thought that there were ten exons in grass carp visfatin gene. The visfatin mRNA was ubiquitously expressed in grass carp through detecting in brain, gill, liver, spleen, head kidney, intestine, mesenteric adipose and muscle tissue.(4) The bluntsnout bream (Megalobrama amblycephala) visfatin cDNA cloned from the liver was～1.5Kb long and contained a1482bp ORF, which encoded a protein of493amino acids. Like the silver Prussian carp, bluntsnout bream visfatin protein had seven cysteine residues, one more than silver Prussian carp visfatin, three N-glycosylation sites and only one tyrosine sulfation site. However, bluntsnout bream visfatin protein had no signal peptide. Furthermore, the complete gene was isolated from fin ray total genomic DNA. The whole gene was～3.0Kb and consisted of9exons and6introns. Though there were not any intron sequences between Exon1and2or Exon3and4, the nucleotides GT and AG were existed at the boundary of Exon1and2, Exon3and4, so it was thought that there were9exons in bluntsnout visfatin gene. The visfatin mRNA was widely expressed in bluntsnout bream carp by testing in brain, gill, liver, spleen, head kidney, intestine, muscle, mesenteric adipose and testis.Conclusions:The coding sequences of visfatin gene were highly homologous in four different teleost fishes, whereas the non-coding sequences showed great variations, for they possessed dissimilar numbers of introns, length of introns and the corresponding introns were comprised of different nucleotide arrangements. The wide expression of visfatin in four fishes indicated that visfatin may distribute broadly and play a fundamental role in teleosts.
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