Natural killer cell receptors in the horse: evidence for the existence of multiple transcribed LY49 genes.
In rodents, the Ly49 family encodes natural killer (NK) receptors interacting with classical MHC class I molecules, whereas the corresponding receptors in primates are members of the killer cell immunoglobulin-like receptor (KIR) family. Recent evidence indicates that the cattle, domestic cat, dog, and pig have a single LY49 and multiple KIR genes, suggesting that predominant NK receptors in most non-rodent mammals might be KIR. Here, we show that the horse has at least six LY49 genes, five with an immunoreceptor tyrosine-based inhibition motif (ITIM) and one with arginine in the transmembrane region. Interestingly, none of the horse KIR-like cDNA clones isolated by library screening encoded molecules likely to function asNK receptors; four types of clones were KIR-Ig-like transcript (KIR-ILT) hybrids and contained premature stop codons and/or frameshift mutations, and two putative allelic sequences predicting KIR3DL molecules had mutated ITIM. To our knowledge, this is the first report suggesting that non-rodent mammals may use LY49 as NK receptors for classical MHC class I. We also show that horse spleen expresses ILT-like genes with unique domain organizations. Radiation hybrid mapping and fluorescence in situ hybridization localized horse LY49 and KIR/ILT genes to chromosomes 6q13 and 10p12, respectively.
Department of Biosystems Science, School of Advanced Sciences, The Graduate University for Advanced Studies (Sokendai), Hayama, Japan.
Tomoko
T
Takahashi
Department of Biosystems Science, School of Advanced Sciences, The Graduate University for Advanced Studies (Sokendai), Hayama, Japan.|present address: Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.
Makoto
M
Yawata
Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, USA.
Terje
T
Raudsepp
M. H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, USA.
Teri L
TL
Lear
Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, USA.
Bhanu P
BP
Chowdhary
James A. Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, USA.
Douglas F
DF
Antczak
Department of Biosystems Science, School of Advanced Sciences, The Graduate University for Advanced Studies (Sokendai), Hayama, Japan.
Masanori
M
Kasahara
D000595:Amino Acid Sequence; D000818:Animals; D000950:Antigens, Ly / Q000145:classification / Q000235:genetics*; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000302:isolation & purification; D006736:Horses / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology*; D037181:Lectins, C-Type; D008969:Molecular Sequence Data; D010802:Phylogeny; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic / Q000145:classification / Q000235:genetics*; D054340:Receptors, KIR; D055630:Receptors, NK Cell Lectin-Like; D016415:Sequence Alignment; D014158:Transcription, Genetic
D000950:Antigens, Ly; D018076:DNA, Complementary; D037181:Lectins, C-Type; D020033:Protein Isoforms; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D055630:Receptors, NK Cell Lectin-Like