title: Genomic analysis and mRNA expression of equine type I interferon genes.
abstract: This study aimed at identifying all of the type I interferon (IFN) genes of the horse and at monitoring their expression in equine cells on in vitro induction. We identified 32 putative type I IFN loci on horse chromosome 23 and an unplaced genomic scaffold. A phylogentic analysis characterized these into 8 different type I IFN classes, that is, putative functional genes for 6 IFN-α, 4 IFN-β, 8 IFN-ω (plus 4 pseudogenes), 3 IFN-δ (plus 1 pseudogene), 1 IFN-κ and 1 IFN-ε, plus 1 IFN-ν pseudogene, and 3 loci belonging to what has previously been called IFN-αω. Our analyses indicate that the IFN-αω genes are quite distinct from both IFN-α and IFN-ω, and we refer to this type I IFN as IFN-μ. Results from cell cultures showed that leukocytes readily expressed IFN-α, IFN-β, IFN-δ, IFN-μ, and IFN-ω mRNA on induction with, for example, live virus; while fibroblasts only expressed IFN-β mRNA on stimulation. IFN-κ or IFN-ε expression was not consistently induced in these cell cultures. Thus, the equine type I IFN family comprised 8 classes, 7 of which had putative functional genes, and mRNA expression of 5 was induced in vitro. Moreover, a relatively low number of IFN-α subtypes was found in the horse compared with other eutherian mammals.
authors.affiliation: 1 Department of Virology, Immunobiology and Parasitology, National Veterinary Institute , Uppsala, Sweden .
authors.forename: Olivier
authors.initials: O
authors.lastname: Detournay
authors.forename: David A
authors.initials: DA
authors.lastname: Morrison
authors.forename: Bettina
authors.initials: B
authors.lastname: Wagner
authors.forename: Behdad
authors.initials: B
authors.lastname: Zarnegar
authors.forename: Eva
authors.initials: E
authors.lastname: Wattrang
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D015870:Gene Expression; D023061:Gene Order; D023281:Genomics; D006736:Horses; D007370:Interferon Type I / Q000235:genetics* / Q000378:metabolism; D016898:Interferon-alpha / Q000235:genetics / Q000378:metabolism; D058977:Molecular Sequence Annotation; D005810:Multigene Family; D016366:Open Reading Frames; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics*
chemical_list: D007370:Interferon Type I; D016898:Interferon-alpha; D012333:RNA, Messenger