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

真核细胞中基因表达的调控在很大程度上是 控制在转录水平上。这种控制是通过 交易因子与顺式调控的相互作用 序列。为了深入了解反式作用的机制， 激活，我们已经进行了研究，以检查 两种病毒早期基因产物SV40的T抗原和E1a蛋白 反式激活人类珠蛋白基因启动子。 由于T抗原和E1a既相似又不同 基因调控的特性，我们认为重要的是要知道 两种病毒蛋白在反式激活中的关系 关于基因表达的。这可能有助于我们理解反式-反式。 聚合酶II转录激活机制的研究进展 真核细胞。在过去的一年里，我们比较了 共转染人T抗原和E1a的反式激活效应 用pRSV-T(质粒组)检测p-epsilon-GLCAT 表达SV40T抗原)或pE1A(表达 腺病毒E1a蛋白)导入CV-1细胞和COS-1细胞。通过 瞬时检测，我们发现T抗原和E1a 反式激活。我们还证明了T抗原可以 对p-epsilon-GLCAT-SV产生额外刺激作用 (增强子+)，但E1a对此无任何影响 质粒组。此外，鉴于将pRSV-T引入COS- 1细胞对p-epsilon-GLCAT的表达没有影响， PE1a的存在使CAT活性大大增加， 与p-epsilon-GLCAT转染法的比较 独自一人。因此，我们的结果表明，T抗原和E1a 用不同的方法反式激活表观珠蛋白启动子 机制，可能是由不同的细胞转录介导的 各种因素。

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.