Mutations in T cell receptor zeta chain mRNA of peripheral T cells from systemic lupus erythematosus patients.
Mutations in T cell receptor zeta chain mRNA of peripheral T cells from systemic lupus erythematosus patients.
复制标题
系统性红斑狼疮患者外周 T 细胞 T 细胞受体 zeta 链 mRNA 突变。
作者：
K. Tsuzaka;Tsutomu Takeuchi;N. Onoda;M. Pang;Tohru Abe
系统性红斑狼疮（SLE）是一种病因不明的全身性自身免疫性疾病。虽然已有研究表明T细胞可能参与SLE的发病机制，但SLE T细胞的免疫畸变是否是SLE发病的主要机制尚不清楚。我们最近报道，酪氨酸磷酸化和表达的T细胞受体zeta链（TCR zeta）显着降低SLE T细胞和两个SLE患者表现出36 bp，外显子7缺失的TCR zeta mRNA。为了进一步研究SLE患者中TCR zeta mRNA的常见突变，从两名正常对照、两名系统性硬化症（SSc）患者和八名SLE患者的外周血T细胞中分离mRNA。通过RT-PCR扩增TCR zeta cDNA。在PCR单链构象多态性分析中，8例SLE患者中有5例表现出TCR zeta cDNA的异常迁移模式。将PCR产物连接到pUC 18中，并对获得的5个克隆进行测序。核苷酸序列分析显示，所有5个pUC 18克隆正常对照和SSc患者有正常的核苷酸序列，而所有8个SLE患者的TCR zeta cDNA突变伴随着预测的氨基酸取代。在这些患者中的6例中发现的突变对应于TCR zeta中的第三免疫受体酪氨酸基活化基序（ITAM）结构域或GTP/GDP结合位点的突变。因此，TCR zeta mRNA中的这些突变可能是导致SLE T细胞中TCR zeta蛋白表达降低的原因。
Systemic lupus erythematosus (SLE) is a systemic autoimmune disease of unknown aetiology. Although it has been reported that T cells might be responsible for the pathogenesis of SLE, it remains unclear whether immune aberrations of SLE T cells are the primary event in this pathological process. We have recently reported that tyrosine phosphorylation and expression of the T cell receptor zeta chain (TCR zeta) was significantly decreased in SLE T cells and that two SLE patients exhibited a 36 bp, exon 7 deletion of the TCR zeta mRNA. To investigate further common mutations in TCR zeta mRNA among SLE patients, mRNA was isolated from the peripheral blood T cells of two normal controls, two systemic sclerosis (SSc) patients, and eight SLE patients. TCR zeta cDNA was amplified by RT-PCR. Five out of the eight SLE patients exhibited abnormal migration patterns of the TCR zeta cDNA in PCR single stranded conformational polymorphism analysis. PCR products were ligated into pUC18 and five clones obtained were sequenced. Analysis of the nucleotide sequences revealed that all of the five pUC18 clones from the normal controls and SSc patients had the normal nucleotide sequence, whereas all eight SLE patients had mutations in TCR zeta cDNA accompanied by predicted amino acid substitutions. Mutations found in six of these patients corresponded to those of the third immunoreceptor tyrosine-based activation motif (ITAM) domain or the GTP/GDP binding site in TCR zetaThus, these mutations in TCR zeta mRNA could be responsible for the decreased expression of the TCR zeta protein in SLE T cells.