Variation in the number of expressed MHC genes in different cattle class I haplotypes
Variation in the number of expressed MHC genes in different cattle class I haplotypes
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DOI：
10.1007/s002510050608
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发表时间：
1999-12-01
期刊：
影响因子：
3.2
通讯作者：
Morrison, WI
中科院分区：
文献类型：
--
作者：
Ellis, SA;Holmes, EC;Morrison, WI
使用血清学和生化方法对牛主要组织相容性复合体（MHC）（BoLA）I类基因表达的分析表明，牛主要组织相容性复合体（MHC）（BoLA）I类基因表达具有高度多态性。然而，I类cDNA序列的分析未能产生关于表达基因的数量和性质的确凿证据。这些信息是必不可少的牛免疫反应的详细研究，并增加我们对MHC进化机制的理解。在这项研究中，选择性育种计划已被用来产生一些MHC纯合子牛表达常见的血清学定义的I类特异性。I类单倍型进行了详细的分析，转录的I类基因的鉴定和特征在于cDNA克隆，序列分析，和转染/表达研究。使用具有确定的BoLA特异性的单克隆抗体证实基因产物在淋巴细胞上的表面表达。可用的转录牛MHC I类序列的系统发育分析揭示了复杂的进化关系，包括重组的可能证据。对个体单倍型的研究表明，某些相关序列的分组可能与基因座相关，但总体而言，使用这种方法不可能定义个体等位基因的起源。这项研究最引人注目的发现是，没有一个牛I类基因是一致表达的，并且与人类相反，单倍型在表达的经典I类基因的数量和组成上彼此不同。
Analysis of cattle major histocompatibility complex (MHC) (BoLA) class I gene expression using serological and biochemical methods has demonstrated a high level of polymorphism. However, analysis of class I cDNA sequences has failed to produce conclusive evidence concerning the number and nature of expressed genes. Such information is essential for detailed studies of cattle immune responses, and to increase our understanding of the mechanisms of MHC evolution. In this study a selective breeding programme has been used to generate a number of MHC homozygous cattle expressing common serologically defined class I specificities. Detailed analysis of five class I haplotypes was carried out, with transcribed class I genes identified and characterized by cDNA cloning, sequence analysis, and transfection/expression studies. Surface expression of the gene products ton lymphocytes) was confirmed using monoclonal antibodies of defined BoLA specificity. Phylogenetic analysis of available transcribed cattle MHC class I sequences revealed complex evolutionary relationships including possible evidence for recombination. The study of individual haplotypes suggests that certain groupings of related sequences may correlate with loci, but overall it was not possible to define the origin of individual alleles using this approach. The most striking finding of this study is that none of the cattle class I genes is consistently expressed, and that in contrast to human, haplotypes differ from one another in both the number and composition of expressed classical class I genes.