Allelic variants of the human MHC class I chain-related B gene (MICB)
Allelic variants of the human MHC class I chain-related B gene (MICB)
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DOI：
10.1007/s002510050311
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发表时间：
1997-11-01
期刊：
影响因子：
3.2
通讯作者：
Inoko, H
中科院分区：
文献类型：
--
作者：
Ando, H;Mizuki, N;Inoko, H
人类主要组织相容性复合体（MHC）位于染色体6p21.3上的一个4兆碱基片段内。最近，在I类区域发现了一个高度分化的MHC I类链相关基因家族MIC。MICA和MICB基因在这个家族中具有独特的组织表达模式。MICA基因是高度多态性的，迄今已鉴定出20多个等位基因。为了阐明MICB等位基因变异的程度，我们对46个HLA纯合子b细胞系的MICB基因的外显子2 （α 1）、3 （α 2）、4 （α 3）和5（跨膜）以及内含子2和4进行了测序。我们报告了基于7个非同义，2个同义和4个内含子核苷酸变异的11个等位基因的鉴定。有趣的是，一个等位基因有一个无义突变，导致α 2结构域的过早终止密码子。因此，MICB似乎比MICA具有更少的等位基因，这与HLA-C和-B位点之间的等位基因比例没有什么不同。MICB等位基因与MICA和HLA-B基因的初步连锁分析显示，MICB和MICA基因之间没有明显的连锁不平衡，这意味着MICB和MICA基因之间存在潜在的重组热点。
The human major histocompatibility complex (MHC) is located within a 4 megabase segment on chromosome 6p21.3. Recently, a highly divergent MHC class I chain-related gene family, MIC was identified within the class I region. The MICA and MICB genes in this family have unique patterns of tissue expression. The MICA gene is highly polymorphic, with more than 20 alleles identified to date. To elucidate the extent of MICB allelic variations, we sequenced exons 2 (alpha 1), 3 (alpha 2), 4 (alpha 3), and 5 (transmembrane) as well as introns 2 and 4 of this gene in 46 HLA homozygous B-cell lines. We report the identification of eleven alleles based on seven non-synonymous, two synonymous, and four intronic nucleotide variations. Interestingly, one allele has a nonsense mutation resulting in a premature termination codon in the alpha 2 domain. Thus, MICB appears to have fewer alleles than MICA, not unlike the allelic ratio between the HLA-C and -B loci. A preliminary linkage analysis of the MICB alleles with those of the closely located MICA and HLA-B genes revealed no conspicuous linkage disequilibrium between them, implying the presence of a potential recombination hotspot between the MICB and MICA genes.