Rellahan B L, Jensen J P, Weissman A M
Laboratory of Immune Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
J Exp Med. 1994 Oct 1;180(4):1529-34. doi: 10.1084/jem.180.4.1529.
The cell surface expression of T cell antigen receptors (TCR) is regulated in part by the limiting synthesis of the zeta subunit. Utilizing fragments from the 5' region of the human zeta gene, two discrete regions that promote transcription were characterized. Both of these elements are located within 125 bases of the most 3' site of transcription initiation. The more proximal (3') promoter exhibits activity in lymphoid as well as nonlymphoid cells. In contrast, the more distal (5') promoter element functions in a tissue-restricted fashion. The tissue-specific promoter is localized to a 29-base fragment. The sequence of this region is remarkable for a stretch of 11 consecutive purines that are required for activity. This element constitutes the only known tissue-specific promoter for an invariant TCR subunit. Consistent with the unique role served by the zeta subunit in assembly of the TCR, this study demonstrates that the expression of the zeta gene is regulated in a fashion distinct from other TCR components.
T细胞抗原受体（TCR）的细胞表面表达部分受ζ亚基有限合成的调控。利用来自人类ζ基因5'区域的片段，鉴定出了两个促进转录的离散区域。这两个元件均位于转录起始最3'位点的125个碱基范围内。较近端（3'）的启动子在淋巴样细胞和非淋巴样细胞中均有活性。相比之下，较远端（5'）的启动子元件以组织限制的方式发挥作用。组织特异性启动子定位于一个29个碱基的片段。该区域的序列因一段连续11个嘌呤而显著，这段嘌呤是活性所必需的。该元件构成了已知唯一的恒定TCR亚基的组织特异性启动子。与ζ亚基在TCR组装中所起的独特作用一致，本研究表明ζ基因的表达调控方式与其他TCR组分不同。
