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大多数基因至少含有两个调节部位,即启动子(promoter)和增强子(enhancer)。前者帮助准确决定DNA转录的起始部位;后者则控制启动子的转录速率。近年来,发现增强子是位于基因旁侧顺序远处的短DNA序列,以顺式调节(cis-regulation)作用于其邻近基因,发挥增强转录的作用;许多病毒及细胞的启动子则受反式作用调节(transregulation)[即其他基因编码的因子能识别一个DNA分子上的某个特异基因并使之开放,以这种方式调节基因表达的基因或产物称作反式作用因子(trans-acting fac-tor)]。目前发现有些病毒(如疱疹病毒、腺病毒和SV40)所编码的蛋白质不但能刺激病毒的启动子的转录,而且还能刺激兔的β-
Most genes contain at least two regulatory sites, the promoter and the enhancer. The former helps determine the exact site of DNA transcription; the latter controls the promoter’s transcription rate. In recent years, it has been found that the enhancer is a short DNA sequence located at a far side of the gene sequence and plays a role in enhancing transcription by cis-regulation of its adjacent genes. Many virus and cell promoters are affected by anti Transregulation [ie, genes encoded by other genes recognize and open a particular gene on a DNA molecule, and genes or products that regulate gene expression in this manner are referred to as trans-acting fac-tor)]. It has been found that some of the viruses (such as herpes virus, adenovirus and SV40) encoded by the protein can not only stimulate the transcription of the virus promoter, but also to stimulate the rabbit β-