NK-lysin of channel catfish: Gene triplication, sequence variation, and expression analysis

Qun Wang, Yaping Wang, Peng Xu, Zhanjiang Liu

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


Antimicrobial peptides (AMPs) are important components of the host innate immune response against microbial invasion. In addition to the previously known four classes of antimicrobial peptides, a fifth class of antimicrobial peptides has been recently identified to include NK-lysins that have a globular three-dimensional structure and are larger with 74-78 amino acid residues. NK-lysin has been shown to harbor antimicrobial activities against a wide spectrum of microorganisms including bacteria, fungi, protozoa, and parasites. To date, NK-lysin genes have been reported from only a limited number of organisms. We previously identified a NK-lysin cDNA in channel catfish. Here we report the identification of two novel types of NK-lysin transcripts in channel catfish. Altogether, three distinct NK-lysin transcripts exist in channel catfish. In this work, their encoding genes were identified, sequenced, and characterized. We provide strong evidence that the catfish NK-lysin gene is tripled in the same genomic neighborhood. All three catfish NK-lysin genes are present in the same genomic region and are tightly linked on the same chromosome, as the same BAC clones harbor all three copies of the NK-lysin genes. All three NK-lysin genes are expressed, but exhibit distinct expression profiles in various tissues. In spite of the existence of a single copy of NK-lysin gene in the human genome, and only a single hit from the pufferfish genome, there are two tripled clusters of NK-lysin genes on chromosome 17 of zebrafish in addition to one more copy on its chromosome 5. The similarity in the genomic arrangement of the tripled NK-lysin genes in channel catfish and zebrafish suggest similar evolution of NK-lysin genes.

Original languageEnglish (US)
Pages (from-to)1676-1686
Number of pages11
JournalMolecular Immunology
Issue number10
StatePublished - Apr 2006
Externally publishedYes


  • Antimicrobial peptide
  • Catfish
  • Disease
  • Fish
  • Gene
  • Innate immunity
  • NK-lysin

ASJC Scopus subject areas

  • Immunology
  • Molecular Biology


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