Multiple β-defensin isoforms identified in early developmental stages of the teleost Paralichthys olivaceus

• Published in: Fish & shellfish immunology Vol. 28; no. 2; pp. 267 - 274
• Main Authors: Nam, Bo-Hye, Moon, Ji-Young, Kim, Young-Ok, Kong, Hee Jeong, Kim, Woo-Jin, Lee, Sang-Jun, Kim, Kyong-Kil
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2010
• Subjects: Amino Acid Sequence; Animals; Anti-Infective Agents - chemistry; Anti-Infective Agents - pharmacology; Base Sequence; beta-Defensins - chemistry; beta-Defensins - genetics; beta-Defensins - immunology; beta-Defensins - pharmacology; Constitutive expression; Early developmental stage; Escherichia coli - drug effects; Flatfishes - growth & development; Flatfishes - immunology; Genome - genetics; Inducible expression; Molecular Sequence Data; Olive flounder; Paralichthys olivaceus; Protein Isoforms; Recombinant Proteins - pharmacology; Sequence Alignment; β-Defensin; Inducible expression; Early developmental stage; Olive flounder; Constitutive expression; Paralichthys olivaceus; β-Defensin
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2009.11.004

The β-defensin-like gene and its cloned isoforms (fBDI-1 to -5) were identified in an expressed sequence tag (EST) library from the early developmental stages of the olive flounder, Paralichthys olivaceus. The fBDI cDNA clones show identical amino acid sequences in 24 residues of the signal peptide and 38 residues of the mature peptide; however, the propiece region varies in sequence and length, from 5 to 15 amino acid residues. The predicted molecular weight of the mature peptide is 3.83 kDa, and its predicted isoelectric point is 4.1, showing anionic properties. The genomic organisation of the isoforms was analysed using bacterial artificial chromosome (BAC) DNA containing the fBDI gene. Southern blotting and sequence analyses of fBDI BAC DNA confirmed that the fBDI isoforms cluster at the same locus and exhibit the conserved gene organisation reported for other fish defensin genes. The fBDI mRNA was expressed constitutively in early developmental stages after hatching, and pathogen challenge induced fBDI expression in the head kidney of juvenile fish. We also produced a recombinant fBDI peptide (smfBD) using the expression plasmid pET32 and examined its bioactivity toward Escherichia coli.