Extinction of hematopoietic specific transcription factor genes in cell hybrids between hematopoietic and non-hematopoietic cells

我们之前报道了T细胞受体/CD3基因在小鼠T淋巴瘤细胞和成纤维细胞之间的细胞杂交中的表达（Mol.Cell biol.）。， 13: 1943-195,1993；Eur.J.Immunol。科学通报，25:2710-2713,1995)。在本研究中，我们发现1ck基因和免疫球蛋白（Ig）基因的表达分别在T x成纤维细胞和B x胚胎癌（EC）细胞杂交中被抑制。抑制的目标是它们的增强子和启动子。负责TCR/CD3和Ig启动子和增强子的造血转录因子基因，如LEF-1、GATA-3、Ikaros/LyF-1、c-myb、Elf-1、PU的表达。/Spi-B、c-Ets-1、oct -2和ocabg基因在杂交种中被熄灭或抑制，而泛在表达的转录因子基因在杂交种中完全不受抑制。这些结果表明，非造血细胞中可能存在的抑制因子可关闭几种造血细胞特异性转录因子的表达，从而下调淋巴细胞特异性结构基因的表达。

We previously reported that expression of T cell receptor/CD3 genes in cell hybrids between mouse T lymphoma cells and fibroblasts (Mol.Cell biol., 13 : 1943-195,1993 ; Eur.J.Immunol., 25 : 2710-2713,1995). In athe present study, we have found expression of the 1ck gene and the immunoglobulin (Ig) gene was suppressed in T x fibroblast and B x embryonal carcinoma (EC) cell hybrids, respectively. The targets of the suppression were their enhancers and promoters. Expression of the hematopoietic transcription factor genes responsible for TCR/CD3 and Ig promoters and enhancers, such as the LEF-1, GATA-3, Ikaros/LyF-1, c-myb, Elf-1, PU./Spi-B,c-Ets-1, Oct-2and OCABgenes, was extinguished or suppressed in the hybrids, while expression of ubiquitously expressed transcription factor genes was not suppressed at all in the hybrids.These results suggest that putative repressors in non-hematopoietic cells shut off the expression of several hematopoietic cell-specific transcription factors and consequentlydownregulate expression of the lymphoid-specific structural genes.