Schneider J F, Fisher F, Goding C R, Jones N C
Gene Regulation Group, Imperial Cancer Research Fund, London, UK.
EMBO J. 1987 Jul;6(7):2053-60. doi: 10.1002/j.1460-2075.1987.tb02470.x.
To determine whether the transcription regulatory activities of the adenoviral E1a gene play a role in its ability to transform primary cells we have constructed an extensive series of mutations within the E1a gene. The mutants have been characterized for their ability to transactivate the adenoviral early promoters, repress the transcriptional stimulation of the polyoma virus enhancer, establish primary baby rat kidney cells in culture and cooperate with the activated Ha-ras oncogene in morphologically transforming these cells. The mutant phenotypes reveal that: (i) the two transcription regulatory activities of E1a are separable since essential protein domains map within different regions of the protein; (ii) transactivation is unlikely to contribute significantly to E1a-mediated transformation since several isolated mutants lost the ability to transactivate but were nevertheless efficient at transformation; and (iii) both establishment and oncogene cooperation are linked to enhancer repression suggesting that E1a transforms cells by the repression of a cellular enhancer.
为了确定腺病毒E1a基因的转录调控活性是否在其转化原代细胞的能力中发挥作用，我们在E1a基因内构建了一系列广泛的突变体。这些突变体已被鉴定具有以下能力：反式激活腺病毒早期启动子、抑制多瘤病毒增强子的转录刺激、在培养中建立原代幼鼠肾细胞以及与激活的Ha-ras癌基因协同作用使这些细胞发生形态转化。突变体表型显示：（i）E1a的两种转录调控活性是可分离的，因为必需的蛋白质结构域位于蛋白质的不同区域；（ii）反式激活不太可能对E1a介导的转化有显著贡献，因为几个分离的突变体失去了反式激活能力，但在转化方面仍然有效；（iii）建立细胞系和癌基因协同作用都与增强子抑制有关，这表明E1a通过抑制细胞增强子来转化细胞。
