Abstract
Toll-like receptors 3, 7, and 8 (TLR3, TLR7, and TLR8) were studied in the genomes of the domestic horse and several other mammals. The messenger RNA sequences and exon/intron structures of these TLR genes were determined. An equine bacterial artificial chromosome clone containing the TLR3 gene was assigned by fluorescent in situ hybridization to the horse chromosomal location ECA27q16–q17 and this map location was confirmed using an equine radiation hybrid panel. Direct sequencing revealed 13 single-nucleotide polymorphisms in the coding regions of the equine TLR 3, 7, and 8 genes. Of these polymorphisms, 12 were not previously reported. The allelic frequency was estimated for each single-nucleotide polymorphism from genotyping data obtained for 154 animals from five horse breeds. Some of these frequencies varied significantly among different horse breeds. Domain architecture predictions for the three equine TLR protein sequences revealed several conserved regions within the variable leucine-rich repeats between the corresponding horse and cattle TLR proteins. A phylogenetic analysis did not indicate that any significant exchanges had occurred between paralogous TLR7 and TLR8 genes in 20 vertebrate species analyzed.
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This work was supported by grant CI000216 from the National Center for Infectious Diseases, Centers for Disease Control and Prevention, to MAB and AAP.
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Supplemental Table 1
PCR primers and restriction enzymes used to genotype SNPs within the coding regions of the equine TLR3, TLR7, and TLR8 genes (DOC 28 kb)
Supplemental Table 2
PCR primers used to amplify mammalian TLR3 genes (DOC 24 kb)
Supplemental Table 3
PCR primers used to amplify the middle regions of various mammalian TLR7 mRNAs (DOC 24 kb)
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Astakhova, N.M., Perelygin, A.A., Zharkikh, A.A. et al. Characterization of equine and other vertebrate TLR3, TLR7, and TLR8 genes. Immunogenetics 61, 529–539 (2009). https://doi.org/10.1007/s00251-009-0381-z
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DOI: https://doi.org/10.1007/s00251-009-0381-z