Extinction of TCR/CD3 and lck gene expression in somatic cell hybrids.

细胞分化过程中细胞类型特异性基因表达的调控是一个复杂的过程，涉及多种正负调控因子的相互作用。体细胞杂交系统已被用于研究细胞类型特异性基因的层级负调控，我们发现在T细胞x成纤维细胞杂交中TCR/CD3和lck基因的表达被抑制。在杂交瘤中，淋巴组织特异性转录因子Lef-1、Tcf-1、GATA-3、Ikaros/Lyf-1、Elf-1、Myb和Fli-1等基因的表达被抑制，而Sp-1、Ets-2和CREB等普遍表达的转录因子基因的表达没有被抑制。这些结果表明，成纤维细胞中可能的阻遏物关闭了几种淋巴组织特异性转录因子的表达，从而下调了T细胞结构基因的表达。

The regulation of expression of cell type-specific genes during cell differentiation is a complex process involving interaction between multiple positive and negative reguratory factors. The somatic cell hybrid system has been used to study hierarchial negative regulation of cell type-specific genes.We found that expression of the TCR/CD3 and lck genes is extinguished in T cell x fibroblast cell hybrids. In the hybrids, expression of the genes encoding lymphoid-specific transcription factors, such as LEF-1, TCF-1, GATA-3, Ikaros/LyF-1, Elf-1, Myb and Fli-1, is extinguished, while that of the genes encoding ubiquitously expressed transcription factors, such as Sp-1, Ets-2 and CREB,is not extinguished.These results suggest that putative repressors in fibroblast shut off the expression of several lymphoid-specific transcription factors and consequently downregulate T cell specific structural gene expression.