Expression of the SH2D1A gene is regulated by a combination of transcriptional and post-transcriptional mechanisms
Expression of the SH2D1A gene is regulated by a combination of transcriptional and post-transcriptional mechanisms
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DOI：
10.1002/eji.200324755
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发表时间：
2004-11-01
影响因子：
5.4
通讯作者：
Terhorst, C
中科院分区：
文献类型：
--
作者：
Okamoto, S;Ji, HB;Terhorst, C
SH 2D 1A基因在X连锁淋巴组织增生性疾病患者中发生改变或缺失，编码在T细胞和NK细胞中表达的小蛋白SAP（SLAM相关蛋白）。紧邻启动子样位点的22-bp片段被定义为小鼠SH 2D 1A的基础启动子，高度同源的33-bp片段被定义为人类基础启动子。当Ets共有位点突变时，检测不到报告活性。凝胶迁移率超移分析表明，两个转录因子Ets-1和Ets-2结合到人类和小鼠的序列。Ets-1和Ets-2参与SH 2D 1A表达的功能通过其显性负性形式的过表达研究得到证实。我们还发现SH 2D 1A mRNA在小鼠T细胞中非常迅速地衰减，并且其3'非翻译区（UTR）在用报告基因/3' UTR构建体的转染研究中具有RNA去稳定化活性。如通过RNA凝胶迁移率变动分析所判断的，SH 2D 1A mRNA的这种快速降解是由于因子AIJF 1和HuR与其3' UTR的结合平衡。尽管在触发T细胞受体（TCR）时SH 2D 1A mRNA水平降低，但RNA降解速率本身不因TCR接合而改变。
The SH2D1A gene, which is altered or deleted in patients with X-linked lymphoproliferative disease, encodes the small protein SAP (for SLAM-associated protein) that is expressed in T and NK cells. A 22-bp fragment in close proximity to an initiator-like site was defined as the basal promoter of mouse SH2D1A, and a highly homologous 33-bp segment was defined as the human basal promoter. When an Ets consensus site was mutated, no reporter activity was detectable. Gel mobility supershift assays revealed that the two transcription factors Ets-1 and Ets-2 bind to the human and mouse sequences. The involvement of Ets-1 and Ets-2 in expression of SH2D1A was functionally confirmed by overexpression studies of their dominant-negative forms. We also found that SH2D1 A mRNA decays very rapidly in mouse T cells, and its 3' untranslated region (UTR) has RNA-destabilizing activity in transfection studies with reporter/3' UTR constructs. As judged by RNA-gel mobility shift assays, this rapid degradation of SH2D1A mRNA was due to a balance in binding of the factors AIJF1 and HuR to its 3' UTR. Although the SH2D1 A mRNA level decreased upon triggering of the T cell receptor (TCR), the RNA degradation rate itself was not altered by TCR engagement.