Novel cathelicidins in horse leukocytes

• Published in: FEBS letters Vol. 457; no. 3; pp. 459 - 464
• Main Authors: Scocchi, Marco, Bontempo, Daniela, Boscolo, Sabrina, Tomasinsig, Linda, Giulotto, Elena, Zanetti, Margherita
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 03.09.1999
• Subjects: Amino Acid Sequence; Animals; Antimicrobial Cationic Peptides - drug effects; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - metabolism; Antimicrobial peptide; Base Sequence; Blood Proteins - genetics; Blood Proteins - metabolism; Blotting, Southern; Blotting, Western; Cathelicidin; Cathelicidins; Cytoplasmic Granules - metabolism; Horse; Horses - physiology; Leukocytes - physiology; Molecular Sequence Data; Multigene Family - genetics; Neutrophils - drug effects; Neutrophils - metabolism; Protein Precursors - genetics; Protein Precursors - metabolism; Reference Values; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis; Sequence Homology, Amino Acid; Short interspersed nucleotide element; Short Interspersed Nucleotide Elements - genetics; Tetradecanoylphorbol Acetate - pharmacology; Transcription, Genetic; Cathelicidin; Short interspersed nucleotide element; Horse; Antimicrobial peptide
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(99)01097-2

Cathelicidins are precursors of defense peptides of the innate immunity and are widespread in mammals. Their structure comprises a conserved prepropiece and an antimicrobial domain that is structurally varied both intra- and inter-species. We investigated the complexity of the cathelicidin family in horse by a reverse transcription-PCR-based cloning strategy of myeloid mRNA and by Southern and Western analyses. Three novel cathelicidin sequences were deduced from bone marrow mRNA and designated equine cathelicidins eCATH-1, eCATH-2 and eCATH-3. Putative antimicrobial domains of 26, 27 and 40 residues with no significant sequence homology to other peptides were inferred at the C-terminus of the sequences. Southern analysis of genomic DNA using a probe based on the cathelicidin-conserved propiece revealed a polymorphic DNA region with several hybridization-positive fragments and suggested the presence of additional genes. A null eCATH-1 allele was also demonstrated with a frequency of 0.71 in the horse population analyzed and low amounts of eCATH-1-specific mRNA were found in myeloid cells of gene-positive animals. A Western analysis using antibodies to synthetic eCATH peptides revealed the presence of eCATH-2 and eCATH-3 propeptides, but not of eCATH-1-related polypeptides, in horse neutrophil granules and in the secretions of phorbol myristate acetate-stimulated neutrophils. These results thus suggest that eCATH-2 and eCATH-3 are functional genes, whereas eCATH-1 is unable to encode a polypeptide.