【摘要】 目的：研究ｃＡＭＰ对ｌａｃ基因启动子体外转录的影响作用。方法：以含ｌａｃ基因启动子及其Ｚ结构基因的线性ｐＵＲ２２２ＤＮＡ为模板，观察Ｅ．ｃｏｌｉＲＮＡ聚合酶受ｃＡＭＰ作用后的转录强度。结果：０．１０～０．８０ｍｍｏｌ／Ｌ的ｃＡＭＰ对ｌａｃ基因启动子体外转录有明显的促进作用，低于０．１０ｍｍｏｌ／Ｌ对体外非特异性转录有促进作用；浓度进一步增高对转录起抑制作用。ｃＡＭＰ作用下特异性与非特异性转录产物放射活性间无相关性。结论：ｃＡＭＰ对转录有双重作用，这种作用可能与启动子区的构象特点及ＲＮＡ聚合酶与启动子的特异结合有关。更多还原

【Abstract】 Objective: Our objective was to study the effect of cyclic adenosine monophosphate(cAMP) on the lac gene promoter transcription in vitro. Methods: We used the linear pUR 222 DNA,which contained lac gene promoter and it’s Z structural gene,as the template to investigate the transcriptional activity of E.coli RNA polymerase under the effect of cAMP. Results: The transcription of lac gene promoter was markedly promoted by 0.10-0.80 mmol/L cAMP and the nonspecific transcription was elevated by cAMP under 0.10 mmol/L. The transcription was inhibited when the concentration of cAMP was higher. There was no significant correlation between the radioactivity of specific and nonspecific transcription products under the effect of cAMP. Conclusion: The effcet of cAMP on the transcription was dualistic and this effect might have relation to the conformation of promoter and the specific combination of RNA polymerase with promoter.更多还原