Bovine β-defensin gene family: opportunities to improve animal health?
Recent analysis of the bovine genome revealed an expanded suite of β-defensin genes that encode what are referred to as antimicrobial or host defense peptides (HDPs). Whereas primate genomes also encode α- and θ-defensins, the bovine genome contains only the β-defensin subfamily of HDPs. β-Defensins perform diverse functions that are critical to protection against pathogens but also in regulation of the immune response and reproduction. As the most comprehensively studied subclass of HDPs, β-defensins possess the widest taxonomic distribution, found in invertebrates as well as plants, indicating an ancient point of origin. Cross-species comparison of the genomic arrangement of β-defensin gene repertoire revealed them to vary in number among species presumably due to differences in pathogenic selective pressures but also genetic drift. β-Defensin genes exist in a single cluster in birds, but four gene clusters exist in dog, rat, mouse, and cow. In humans and chimpanzees, one of these clusters is split in two as a result of a primate-specific pericentric inversion producing five gene clusters. A cluster of β-defensin genes on bovine chromosome 13 has been recently characterized, and full genome sequencing has identified extensive gene copy number variation on chromosome 27. As a result, cattle have the most diverse repertoire of β-defensin genes so far identified, where four clusters contain at least 57 genes. This expansion of β-defensin HDPs may hold significant potential for combating infectious diseases and provides opportunities to harness their immunological and reproductive functions in commercial cattle populations.
Animal & Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Co. Meath, Ireland;
K G
KG
Meade
P
P
Cormican
F
F
Narciandi
A
A
Lloyd
C
C
O'Farrelly
D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism; D002417:Cattle / Q000235:genetics*; D019143:Evolution, Molecular; D006262:Health; D056747:Immunomodulation / Q000235:genetics; D005810:Multigene Family; D023083:beta-Defensins / Q000235:genetics* / Q000378:metabolism
D000890:Anti-Infective Agents; D023083:beta-Defensins
bovine; fertility; immunology; β-defensin