Cod cathelicidin: isolation of the mature peptide, cleavage site characterisation and developmental expression.
Cathelicidin antimicrobial peptides are multifunctional peptides that are important in the innate immune system of mammals. Cathelicidins have been identified in several fish species. In this study we have isolated cathelicidin from Atlantic cod (Gadus morhua) and identified the cleavage site from the cathelin propart. This is the first isolation of a cathelicidin from teleost fish. The mature cathelicidin was found to be a 67-residues peptide, highly cationic with a pI of 13. Reversed phase chromatographic fractions containing the purified peptide had pronounced antimicrobial activity and the activity of the mature peptide was confirmed using a synthetic peptide. We examined the expression of cathelicidin during cod larvae early development using real-time PCR and detected expression that varied in the course of the first 68 days post hatching (dph). Two groups of larvae having a different food regime were compared. Cathelicidin expression was found to differ between the two groups and this could be linked to their food input. The presence and rapid adjustment of cathelicidin expression in the larvae indicate that the immune system of cod is active from early on in development and responds to external stimuli by the production of antimicrobial peptides.
Institute of Biology, University of Iceland, Sturlagata 7, 101 Reykjavik, Iceland.
Daniela C
DC
Broekman
Dominik M
DM
Frei
Gudjon A
GA
Gylfason
Agnar
A
Steinarsson
Hans
H
Jörnvall
Birgitta
B
Agerberth
Gudmundur H
GH
Gudmundsson
Valerie H
VH
Maier
D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D015153:Blotting, Western; D048389:Gadus morhua / Q000235:genetics* / Q000276:immunology*; D015870:Gene Expression; D020869:Gene Expression Profiling; D007814:Larva; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054804:Cathelicidins
D023181:Antimicrobial Cationic Peptides; D012333:RNA, Messenger; D054804:Cathelicidins