Simmen K A, Mattaj I W
European Molecular Biology Laboratory, Heidelberg, FRG.
Nucleic Acids Res. 1990 Oct 11;18(19):5649-57. doi: 10.1093/nar/18.19.5649.
The role of various sequences in determining the RNA polymerase III (pol III) specificity of the Xenopus U6 gene promoter has been investigated. A sequence closely resembling an RNA polymerase II (pol II) TATA box, which has previously been implicated in determining the pol III specificity of the U6 promoter, was analyzed in detail. The U6 TATA-like element, in a different promoter context, is shown to be capable of mediating RNA polymerase II transcription both in vitro and in oocyte microinjection experiments. Extensive mutagenesis of the TATA-like element in the context of the pol III and pol II promoters leads to the conclusion that the sequence requirements for function in the two contexts are dissimilar, suggesting that different factors may be involved in mediating pol II and pol III transcription. Further, as implied by the above results, it is shown that the polymerase III specificity of the U6 gene is not solely dependent upon the TATA-like element but rather reflects complex interaction between multiple components of the promoter.
已对非洲爪蟾U6基因启动子中各种序列在决定RNA聚合酶III（pol III）特异性方面的作用进行了研究。详细分析了一个与RNA聚合酶II（pol II）TATA框非常相似的序列，该序列先前被认为与决定U6启动子的pol III特异性有关。在不同的启动子背景下，U6类TATA元件在体外和卵母细胞显微注射实验中均显示能够介导RNA聚合酶II转录。在pol III和pol II启动子背景下对类TATA元件进行广泛诱变后得出结论，两种背景下发挥功能的序列要求不同，这表明可能有不同的因子参与介导pol II和pol III转录。此外，如上述结果所暗示的，研究表明U6基因的聚合酶III特异性并非仅取决于类TATA元件，而是反映了启动子多个组分之间的复杂相互作用。
