Weiher H, Botchan M R
Nucleic Acids Res. 1984 Mar 26;12(6):2901-16. doi: 10.1093/nar/12.6.2901.
A comprehensive structural analysis of an enhancer sequence from bovine papilloma virus DNA is presented based on the construction and functional analysis of 20 mutant derivatives. The results, obtained in CV-1 tissue culture cells, show that this enhancer is a small genetic element--only 40 bp in length--that contains two essential regions. The two regions exhibit homology to each other and to DNA fragments from other viral genomes that also act as enhancers in the assay used. However, there is a certain latitude in the sequences that have enhancer activity in CV-1 cells, even within the critical regions. The results are discussed with respect to the model that enhancers are binding sites for tissue specific transcription factors. The formation of Z-DNA might be involved in the enhancement process. However, single base pair transitions in an 8 base pair stretch of alternating purines and pyrimidines within the BPV enhancer which conserve this pattern destroy enhancer function.
基于20种突变衍生物的构建和功能分析，对牛乳头瘤病毒DNA的增强子序列进行了全面的结构分析。在CV-1组织培养细胞中获得的结果表明，该增强子是一个小的遗传元件，长度仅为40个碱基对，包含两个必需区域。这两个区域彼此之间以及与其他病毒基因组的DNA片段具有同源性，在所用测定中这些片段也充当增强子。然而，即使在关键区域内，在CV-1细胞中具有增强子活性的序列也存在一定的变化范围。结合增强子是组织特异性转录因子结合位点的模型对结果进行了讨论。Z-DNA的形成可能参与增强过程。然而，牛乳头瘤病毒增强子内一段由嘌呤和嘧啶交替组成的8个碱基对延伸中的单碱基对转换，虽保留了这种模式却破坏了增强子功能。
