Jensen J P, Hou D, Ramsburg M, Taylor A, Dean M, Weissman A M
Experimental Immunology Branch, DCBDC/National Cancer Institute National Institutes of Health, Bethesda, MD 20892.
J Immunol. 1992 Apr 15;148(8):2563-71.
The zeta-subunit is the most recently characterized stoichiometric human TCR component. In this study we describe the molecular organization of the human zeta-gene. The zeta transcript is generated as the spliced product of eight exons that are separated by distances of 0.7 kb to more than 8 kb. Ribonuclease protection studies revealed multiple transcription initiation sites distributed over a range of approximately 115 bases. A variable number tandem repeat restriction fragment polymorphism contained within the structural gene has allowed for the localization of zeta within the human genome. Additionally, a restriction fragment polymorphism within the Fc gamma RII-Fc gamma RIII gene cluster has allowed for its localization on the map of human chromosome 1q and for the establishment of its linkage to the zeta-gene locus. A region that is highly homologous on a nucleotide level with the eta-exon of the murine zeta-gene is localized to the 3' region of the human zeta-gene. Surprisingly, translation of this region into protein results in a structure that is markedly divergent from its murine counterpart. This finding has important implications regarding the potential role of eta in T cell function.
ζ亚基是最近才被鉴定出化学计量的人类T细胞受体（TCR）组分。在本研究中，我们描述了人类ζ基因的分子结构。ζ转录本是由8个外显子的剪接产物产生的，这些外显子之间的距离在0.7kb到超过8kb之间。核糖核酸酶保护研究揭示了多个转录起始位点分布在大约115个碱基的范围内。结构基因中包含的可变数目串联重复序列限制性片段多态性，使得ζ基因在人类基因组中的定位成为可能。此外，FcγRII-FcγRIII基因簇内的一个限制性片段多态性，使其能够定位在人类1号染色体的图谱上，并确定其与ζ基因座的连锁关系。在核苷酸水平上与小鼠ζ基因的η外显子高度同源的一个区域，位于人类ζ基因的3'区域。令人惊讶的是，该区域翻译成蛋白质后产生的结构与小鼠对应物明显不同。这一发现对于η在T细胞功能中的潜在作用具有重要意义。
