Research group Animal Immunogenomics, CEITEC VETUNI, University of Veterinary Sciences Brno, Brno, Czechia.
Department of Animal Genetics, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czechia.
HLA. 2023 Oct;102(4):489-500. doi: 10.1111/tan.15078. Epub 2023 Apr 27.
The major histocompatibility complex (MHC) with its class I and II genes plays a crucial role in the immune response to pathogens by presenting oligopeptide antigens to various immune response effector cells. In order to counteract the vast variability of infectious agents, MHC class I and II genes usually retain high levels of SNPs mainly concentrated in the exons encoding the antigen binding sites. The aim of the study was to reveal new variability of selected MHC genes with a special focus on MHC class I physical haplotypes. Long-range NGS to was used to identify exon 2-exon 3 alleles in three genetically distinct horse breeds. A total of 116 allelic variants were found in the MHC class I genes Eqca-1, Eqca-2, Eqca-7 and Eqca-Ψ, 112 of which were novel. The MHC class II DRA locus was confirmed to comprise five exon 2 alleles, and no new sequences were observed. Additional variability in terms of 15 novel exon 2 alleles was identified in the DQA1 locus. Extensive overall variability across the entire MHC region was confirmed by an analysis of MHC-linked microsatellite loci. Both diversifying and purifying selection were detected within the MHC class I and II loci analyzed.
主要组织相容性复合体（MHC）及其 I 类和 II 类基因在针对病原体的免疫反应中发挥着关键作用，通过向各种免疫反应效应细胞呈递寡肽抗原。为了对抗传染性病原体的巨大变异性，MHC I 类和 II 类基因通常保留高水平的 SNP，主要集中在编码抗原结合位点的外显子中。本研究旨在揭示所选 MHC 基因的新变异性，特别关注 MHC I 类物理单倍型。长距离 NGS 用于鉴定三个遗传上不同的马品种的 MHC I 基因 Eqca-1、Eqca-2、Eqca-7 和 Eqca-Ψ 的外显子 2-外显子 3等位基因。在 MHC I 基因 Eqca-1、Eqca-2、Eqca-7 和 Eqca-Ψ 中发现了 116 个等位基因变体，其中 112 个是新的。MHC II DRA 基因座被证实包含 5 个外显子 2 等位基因，没有观察到新的序列。在 DQA1 基因座中还发现了 15 个新的外显子 2 等位基因的额外变异性。通过 MHC 连锁微卫星基因座的分析，证实了整个 MHC 区域的广泛总体变异性。在分析的 MHC I 类和 II 类基因座中均检测到多样化和纯化选择。
