title: Bioinformatic discovery and initial characterisation of nine novel antimicrobial peptide genes in the chicken.
abstract: Antimicrobial peptides (AMPs) are essential components of innate immunity in a range of species from Drosophila to humans and are generally thought to act by disrupting the membrane integrity of microbes. In order to discover novel AMPs in the chicken, we have implemented a bioinformatic approach that involves the clustering of more than 420,000 chicken expressed sequence tags (ESTs). Similarity searching of proteins-predicted to be encoded by these EST clusters-for homology to known AMPs has resulted in the in silico identification of full-length sequences for seven novel gallinacins (Gal-4 to Gal-10), a novel cathelicidin and a novel liver-expressed antimicrobial peptide 2 (LEAP-2) in the chicken. Differential gene expression of these novel genes has been demonstrated across a panel of chicken tissues. An evolutionary analysis of the gallinacin family has detected sites-primarily in the mature AMP-that are under positive selection in these molecules. The functional implications of these results are discussed.
authors.affiliation: Education and Research Centre, St. Vincent's University Hospital, 4, Dublin, Ireland.
authors.forename: David J
authors.initials: DJ
authors.lastname: Lynn
authors.forename: Rowan
authors.initials: R
authors.lastname: Higgs
authors.forename: Susan
authors.initials: S
authors.lastname: Gaines
authors.forename: Joanna
authors.initials: J
authors.lastname: Tierney
authors.forename: Tharappel
authors.initials: T
authors.lastname: James
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Lloyd
authors.forename: Mario A
authors.initials: MA
authors.lastname: Fares
authors.forename: Grace
authors.initials: G
authors.lastname: Mulcahy
authors.forename: Cliona
authors.initials: C
authors.lastname: O'Farrelly
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D030161:Avian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002645:Chickens / Q000235:genetics* / Q000378:metabolism; D019295:Computational Biology / Q000379:methods*; D023082:Defensins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D005796:Genes; D008390:Markov Chains; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
chemical_list: D023181:Antimicrobial Cationic Peptides; D030161:Avian Proteins; D023082:Defensins