TRANS-ACTIVATION OF GLOBIN PROMOTERS BY SV40 T-ANTIGEN AND ADENOVIRUS EIA

真核细胞中基因表达的调控主要是 控制在转录水平。 这种控制是通过 通过反式作用因子和顺式调节因子的相互作用 序列的 为了深入了解反式- 激活，我们已经进行了研究，以检查的能力， 两种病毒早期基因产物，SV 40的T抗原和E1 A蛋白 的腺病毒，以反式激活人珠蛋白基因启动子。 由于T抗原与E1 A抗原既有相似性又有区别， 我们认为了解基因调控的特性很重要 两种病毒蛋白在反式激活中的关系 的基因表达。 这可能有助于我们理解跨- 聚合酶II转录的激活机制 真核细胞 在过去的一年里，我们比较了 T抗原和E1 A的反式激活作用 用pRSV-T（质粒pRSV-T）或pRSV-T-GLCAT（质粒pRSV-GLCAT）检测质粒p-GLCAT 表达SV 40 T抗原的质粒）或pE 1A（表达 腺病毒的E1 A蛋白）导入CV-1细胞和COS-1细胞。 通过 瞬时检测，我们发现，虽然T抗原和E1 A 反式激活 我们还证明了T抗原可以 对p-Glu-GLCAT-SV产生额外的刺激作用 （增强子+），但E1 A对此无任何影响 质粒 此外，尽管将pRSV-T导入COS- 1细胞对p-GLCAT表达没有影响， pE 1A的存在使CAT活性大大增加， 与用p-Glu-GLCAT进行的转染相比 一个人 因此，我们的结果表明，T抗原和E1 A 通过使用不同的方法反式激活ε-珠蛋白启动子， 机制，可能是由不同的细胞转录介导 因素

Regulation of gene expression in eukaryotic cells is largely controlled at the level of transcription. This control is mediated by interactions of transacting factors and cis-regulatory sequences. To gain some insights into the mechanisms of trans- activation, we have undertaken studies to examine the ability of two viral early gene products, T antigen of SV40 and E1A protein of adenovirus, to trans-activate human globin gene promoters. Since T antigen and E1A possess both similar and distinct properties in gene regulation, we thought it is important to know the relationship between the two viral proteins in trans-activation of gene expression. This may help us to understand the trans- activation mechanisms of polymerase II transcription in eukaryotic cells. During the past year, we have compared the trans-activation effect of T antigen and E1A by co-transfecting a testing plasmid p-epsilon-GLCAT with either pRSV-T (plasmid expressing the SV40 T antigen) or pE1A (plasmid expressing the E1A protein of adenovirus) into CV-1 cells and COS-1 cells. By transient assay, we found that while both T antigen and E1A trans-activation. We also demonstrated that T antigen can produce additional stimulatory effect on p-epsilon-GLCAT-SV (enhancer+) in CV-1 cells, but E1A has no any effect on this plasmid. Furthermore, whereas introduction of pRSV-T into COS- 1 cells had no effect on p-epsilon-GLCAT expression, the presence of pE1A produced great increase in CAT activity, compared with transfection carried out with p-epsilon-GLCAT alone. Our results, therefore, suggest that T antigen and E1A trans-activate the epsilon-globin promoter by using different mechanisms, probably mediated by different cellular transcription factors.