At least four MHC class I genes are transcribed in the horse: phylogenetic analysis suggests an unusual evolutionary history for the MHC in this species.
Abstract: Nineteen horse MHC class I specificities have been serologically identified previously at a single locus (ELA-A), and two other specificities appear to be coded at other loci. Biochemical studies indicate that there are at least two expressed loci. In order to establish the number of transcribed horse MHC class I genes, we made a cDNA library from a heterozygous animal (ELA-A3/A7), and screened for positive clones using a bovine class I probe. More than 200 class I clones were isolated in this way, and so far seven unique full length sequences have been identified. All of the sequences are predicted to code for surface expressed, functional molecules. The number of different sequences identified demonstrate that at least four genes are transcribed, although variations in transmembrane length (which is generally conserved in class I loci) suggest that five genes could be represented. Evolutionary analysis of these sequences (and two additional sequences known to represent different horse class I loci) reveals no firm relationships, such that the division between the different loci cannot be discerned. These results suggest an unusual evolutionary history for the horse MHC, the precise nature of which may be revealed only following further cross-species comparisons.
Publication Date: 1995-06-01 PubMed ID: 8547231DOI: 10.1111/j.1744-313x.1995.tb00239.xGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research presents an attempt to establish how many MHC class I genes are transcribed in horses, suggesting a different evolutionary history for the Major Histocompatibility Complex (MHC) in this species, with at least four genes being identified.
Understanding MHC Class I Genes
- The MHC class I genes play a crucial role in the immune system, helping to recognize foreign molecules within the body and initiate an immune response.
- In horses, 19 MHC class I specificities had previously been serologically identified at a single locus named ELA-A. Additionally, two other specificities are believed to be encoded at other loci.
Study Approach and Findings
- The researchers used a cDNA library from a heterozygous horse (having different alleles at a specific locus), identified as ELA-A3/A7, to establish the number of horse MHC class I genes transcribed.
- A bovine class I probe was used for the screening for positive clones, resulting in the isolation of more than 200 class I clones.
- Seven unique full-length sequences were identified and predicted to code for functional, surface-expressed molecules.
Implications and Further Research
- The varying sequences demonstrate that at least four genes are transcribed, suggesting the existence of additional transcribed genes that could not be identified due to variations in transmembrane length.
- When comparing these sequences (and two additional sequences which represent different horse class I loci), no firm relationships were found, making it impossible to determine the division between the different loci.
- This indicates an unusual evolutionary history for the horse MHC, however, the exact nature of this will need to be identified through further studies and cross-species comparisons.
Cite This Article
APA
Ellis SA, Martin AJ, Holmes EC, Morrison WI.
(1995).
At least four MHC class I genes are transcribed in the horse: phylogenetic analysis suggests an unusual evolutionary history for the MHC in this species.
Eur J Immunogenet, 22(3), 249-260.
https://doi.org/10.1111/j.1744-313x.1995.tb00239.x Publication
Researcher Affiliations
- Institute for Animal Health, Compton Laboratory, UK.
MeSH Terms
- Amino Acid Sequence
- Animals
- Base Sequence
- Cattle
- DNA, Complementary / genetics
- Genes, MHC Class I
- Histocompatibility Antigens Class I / genetics
- Horses / genetics
- Humans
- Major Histocompatibility Complex / genetics
- Molecular Sequence Data
- Phylogeny
- Polymorphism, Genetic
- Sequence Alignment
- Sequence Homology
- Sheep
- Species Specificity
Citations
This article has been cited 19 times.- Vasoya D, Tzelos T, Benedictus L, Karagianni AE, Pirie S, Marr C, Oddsdóttir C, Fintl C, Connelley T. High-Resolution Genotyping of Expressed Equine MHC Reveals a Highly Complex MHC Structure.. Genes (Basel) 2023 Jul 10;14(7).
- Kremling V, Loll B, Pach S, Dahmani I, Weise C, Wolber G, Chiantia S, Wahl MC, Osterrieder N, Azab W. Crystal structures of glycoprotein D of equine alphaherpesviruses reveal potential binding sites to the entry receptor MHC-I.. Front Microbiol 2023;14:1197120.
- Ismail NA, Yong CSY, Sin SYW, Annavi G. Low Diversity of Major Histocompatibility Complex (MHC) Genes in Endangered Malayan Tapir (Tapirus indicus).. Zool Stud 2023;62:e12.
- Obara I, Nijhof A, Atimnedi P, Mijele D, Nanteza A, Elati K, Bishop R. The antigen recognition portion of African buffalo class I MHC is highly polymorphic, consistent with a complex pathogen challenge environment, and the 3' region suggests distinct haplotype configurations.. Immunogenetics 2023 Apr;75(2):115-132.
- Siva Subramaniam N, Morgan EF, Wetherall JD, Stear MJ, Groth DM. A comprehensive mapping of the structure and gene organisation in the sheep MHC class I region.. BMC Genomics 2015 Oct 19;16:810.
- Ramsay JD, Leib SR, Orfe L, Call DR, Tallmadge RL, Fraser DG, Mealey RH. Development of a DNA microarray for detection of expressed equine classical MHC class I sequences in a defined population.. Immunogenetics 2010 Sep;62(9):633-9.
- Kurtz BM, Singletary LB, Kelly SD, Frampton AR Jr. Equus caballus major histocompatibility complex class I is an entry receptor for equine herpesvirus type 1.. J Virol 2010 Sep;84(18):9027-34.
- Tallmadge RL, Campbell JA, Miller DC, Antczak DF. Analysis of MHC class I genes across horse MHC haplotypes.. Immunogenetics 2010 Mar;62(3):159-72.
- Mealey RH, Lee JH, Leib SR, Littke MH, McGuire TC. A single amino acid difference within the alpha-2 domain of two naturally occurring equine MHC class I molecules alters the recognition of Gag and Rev epitopes by equine infectious anemia virus-specific CTL.. J Immunol 2006 Nov 15;177(10):7377-90.
- Tallmadge RL, Lear TL, Antczak DF. Genomic characterization of MHC class I genes of the horse.. Immunogenetics 2005 Nov;57(10):763-74.
- Miltiadou D, Ballingall KT, Ellis SA, Russell GC, McKeever DJ. Haplotype characterization of transcribed ovine major histocompatibility complex (MHC) class I genes.. Immunogenetics 2005 Aug;57(7):499-509.
- Chung C, Mealey RH, McGuire TC. CTL from EIAV carrier horses with diverse MHC class I alleles recognize epitope clusters in Gag matrix and capsid proteins.. Virology 2004 Sep 15;327(1):144-54.
- Go Y, Satta Y, Kawamoto Y, Rakotoarisoa G, Randrianjafy A, Koyama N, Hirai H. Frequent segmental sequence exchanges and rapid gene duplication characterize the MHC class I genes in lemurs.. Immunogenetics 2003 Oct;55(7):450-61.
- Mealey RH, Zhang B, Leib SR, Littke MH, McGuire TC. Epitope specificity is critical for high and moderate avidity cytotoxic T lymphocytes associated with control of viral load and clinical disease in horses with equine infectious anemia virus.. Virology 2003 Sep 1;313(2):537-52.
- Holmes EC, Roberts AF, Staines KA, Ellis SA. Evolution of major histocompatibility complex class I genes in Cetartiodactyls.. Immunogenetics 2003 Jul;55(4):193-202.
- Mealey RH, Fraser DG, Oaks JL, Cantor GH, McGuire TC. Immune reconstitution prevents continuous equine infectious anemia virus replication in an Arabian foal with severe combined immunodeficiency: lessons for control of lentiviruses.. Clin Immunol 2001 Nov;101(2):237-47.
- Hedrick PW, Parker KM, Miller EL, Miller PS. Major histocompatibility complex variation in the endangered Przewalski's horse.. Genetics 1999 Aug;152(4):1701-10.
- Cadavid LF, Shufflebotham C, Ruiz FJ, Yeager M, Hughes AL, Watkins DI. Evolutionary instability of the major histocompatibility complex class I loci in New World primates.. Proc Natl Acad Sci U S A 1997 Dec 23;94(26):14536-41.
- Fraser DG, Bailey E. Demonstration of three DRB loci in a domestic horse family.. Immunogenetics 1996;44(6):441-5.
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