Hirschmann P, Vos J C, Stunnenberg H G
Gene Expression Department, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
J Virol. 1990 Dec;64(12):6063-9. doi: 10.1128/JVI.64.12.6063-6069.1990.
The expression of the vaccinia virus intermediate I3 gene depends on trans-acting factors which are present in an active state prior to DNA replication. However, activation of transcription requires DNA replication in cis (J. C. Vos and H. G. Stunnenberg, EMBO J., 7:3487-3492, 1988). We have made deletion and linker scanner mutations of the I3 promoter to determine the sequence requirements for transcriptional activity and the dependence of DNA replication. The I3 promoter appears to consist of two elements which are essential and sufficient for accurate transcription initiation both in vivo and in vitro. An upstream and a downstream sequence element were defined ranging from -20 to -9 and +1 to +9, respectively. The upstream element appears to be highly homologous to a sequence in the intermediate I8 promoter. A 3-bp substitution in the upstream I3 promoter element resulted in a change of transcriptional specificity from intermediate to late. Finally, the mutations did not result in an activation of the intermediate promoter prior to DNA replication.
痘苗病毒中间基因I3的表达取决于反式作用因子，这些因子在DNA复制之前就处于活性状态。然而，转录的激活需要顺式DNA复制（J.C.沃斯和H.G.斯图嫩贝格，《欧洲分子生物学组织杂志》，7:3487 - 3492，1988）。我们对I3启动子进行了缺失和接头扫描突变，以确定转录活性的序列要求以及对DNA复制的依赖性。I3启动子似乎由两个元件组成，这两个元件对于体内和体外的准确转录起始都是必不可少且足够的。分别定义了一个上游和一个下游序列元件，范围分别为-20至-9和+1至+9。上游元件似乎与中间基因I8启动子中的一个序列高度同源。I3启动子上游元件中的一个3碱基替换导致转录特异性从中间型变为晚期型。最后，这些突变在DNA复制之前并未导致中间启动子的激活。
