FACTORS REQUIRED FOR SPECIFIC TRANSCRIPTION

体外转录系统用于识别启动子信号和 真核系统中控制转录的因子。这些系统 准确地从各种各样的启动子开始转录。在……下面 改进的检测条件下，腺病毒IVa2基因的表达 在体外容易观察到。这种腺基因，就像SV40晚期基因一样， 在5英尺起点的上游没有塔塔包厢。通过构建一系列 在上游缺失突变中，已经确定了两个上游结构域 控制这一基因的基因。远端结构域只有在共价时才起作用 闭合DNA用作模板，其中包含两个独立的 地区。其中一个被认为是RNA聚合酶的进入位点。 第二个区域抑制IVa2基因的转录。

In vitro transcription systems are used to identify promoter signals and factors that control transcription in eucaryotic systems. These systems accurately initiate transcription from a wide variety of promoters. Under modified assay conditions, expression of the adenovirus IVa2 gene is readily observed in vitro. This adeno gene, like the SV40 late genes, lacks a TATA box upstream from the 5' start site. By constructing a series of upstream deletion mutations, two upstream domains have been identified that control this gene. The distal domain only functions when covalently closed DNA is used as a template and contains within it two separate regions. One is believed to function as the entry site for RNA polymerase II while the second region inhibits transcription of the IVa2 gene.