Polymorphisms/mutations of TCR-ζ-chain promoter and 3′ untranslated region and selective expression of TCR ζ-chain with an alternatively spliced 3′ untranslated region in patients with systemic lupus erythematosus
Polymorphisms/mutations of TCR-ζ-chain promoter and 3′ untranslated region and selective expression of TCR ζ-chain with an alternatively spliced 3′ untranslated region in patients with systemic lupus erythematosus
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DOI：
10.1006/jaut.2000.0475
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发表时间：
2001-03-01
影响因子：
12.8
通讯作者：
Tsokos, GC
中科院分区：
文献类型：
--
作者：
Nambiar, MP;Enyedy, EJ;Tsokos, GC
绝大多数系统性红斑狼疮（SLE）患者显示TCR ζ链mRNA表达降低，TCR ζ链mRNA是一种参与TCR库选择和预防自身免疫的关键信号传导分子。为了确定参与SLE T细胞中TCR ζ链转录物下调的分子机制，我们研究了启动子和3'非翻译区中多态性/突变的可能性。基因组DNA启动子区的PCR、克隆和序列分析显示，SLE T细胞中的多态性数量显著高于非SLE对照受试者（P=0.044）。还分析了粒细胞的启动子序列，以描述活化的SLE T细胞中体细胞突变的可能性。SLE患者粒细胞启动子多态性显著高于非SLE对照组（P=0.048），表明这些多态性是基因组起源。启动子序列的核苷酸分析显示，与已发表的序列相比，在所有SLE样品和对照中有-76T插入。TCR ζ链3'非翻译区的RT-PCR分析显示除了预期的906 bp产物之外，还有344 bp产物。对344 bp产物的克隆和序列分析表明，它是一种具有剪接供体和受体位点的选择性剪接形式，导致TCR ζ链mRNA的核苷酸672-1233缺失。与正常TCR ζ链不同，具有可变剪接的344 bp 3'非翻译区的TCR ζ链的表达在SLE T细胞中比非SLE对照更高.与非SLE受试者相比，SLE T细胞中906 bp TCR ζ-链3'非翻译区的突变/多态性的数量显著更高（P=0.032）。下游3'非翻译区的频繁突变/多态性和异常剪接可能影响TCR ζ链mRNA的稳定性和/或转运，导致其在SLE T细胞中下调。(C)北京：科学出版社.
A vast majority of systemic lupus erythematosus (SLE) patients display decreased expression of TCR zeta -chain mRNA, a critical signaling molecule implicated in the selection of the TCR repertoire and in the prevention of autoimmunity. To identify the molecular mechanisms involved in the downregulation of TCR zeta -chain transcripts in SLE T cells, we investigated the possibility of polymorphisms/mutations in the promoter and the 3' untranslated region. PCR, cloning and sequence analysis of the promoter region from the genomic DNA showed significantly higher number of polymorphisms in SLE T cells compared to non-SLE control subjects (P=0.044). Promoter sequence was also analysed from granulocytes to delineate the possibility of somatic mutations in activated SLE T cells. Promoter polymorphisms were significantly higher in granulocytes of SLE patients compared to non-SLE controls (P=0.048), suggesting that these polymorphisms were of genomic origin. Nucleotide analysis of the promoter sequence revealed a -76T insertion compared to the published sequence; in all of the SLE samples and controls. RT-PCR analysis of the TCR zeta -chain 3' untranslated region showed a 344 bp product in addition to the expected 906 bp product. Cloning and sequence analysis of the 344 bp product indicated that it is an alternatively spliced form with both splicing donor and acceptor sites, resulting in deletion of nucleotides 672-1233 of TCR zeta -chain mRNA. Unlike the nomal TCR zeta -chain, the expression of TCR zeta -chain with the alternatively spliced 344 bp 3' untranslated region was higher in SLE T cells compared to non-SLE controls. The number of mutations/polymorphisms in the 906 bp TCR zeta -chain 3' untranslated region were significantly higher in SLE T cells compared to non-SLE subjects (P=0.032). Frequent mutations/polymorphisms and aberrant splicing of the downstream 3' untranslated region may affect the stability and/or transport of TCR zeta -chain mRNA, leading to its downregulation in SLE T cells. (C) 2001 Academic Press.