Ye R, Wong S L
Department of Biological Sciences, University of Calgary, Alberta, Canada.
J Bacteriol. 1994 Jun;176(11):3314-20. doi: 10.1128/jb.176.11.3314-3320.1994.
The regulatory region of the Bacillus subtilis glucitol dehydrogenase (gutB) gene was divided into three subregions: a promoter, an upstream positive regulatory region, and a downstream negative regulatory region. Data from primer extension, deletion, and site-directed mutagenesis analyses were consistent with two possible models for the gutB promoter. It is either a sigma A-type promoter with an unusually short spacer region (15 bp) or a special sigma A promoter which requires only the hexameric -10 sequence for its function. Sequence carrying just the promoter region (from -48 to +6) failed to direct transcription in vivo. An upstream regulatory sequence was essential for glucitol induction. When this sequence was inserted in a high-copy-number plasmid, an effect characteristic of titration of a transcriptional activator was seen. Downstream from the promoter, there is an imperfect, AT-rich inverted repeat sequence. Deletion of this element did not lead to constitutive expression of gutB. However, the induced gutB expression level was enhanced three- to fourfold.
枯草芽孢杆菌葡糖醇脱氢酶（gutB）基因的调控区域被分为三个子区域：一个启动子、一个上游正调控区域和一个下游负调控区域。引物延伸、缺失和定点诱变分析的数据与gutB启动子的两种可能模型一致。它要么是一个间隔区异常短（15bp）的σA 型启动子，要么是一个仅需六聚体-10序列就能发挥功能的特殊σA启动子。仅携带启动子区域（从-48到+6）的序列在体内无法指导转录。一个上游调控序列对于葡糖醇诱导至关重要。当该序列插入高拷贝数质粒时，会出现转录激活剂滴定的特征效应。在启动子下游，有一个不完美的、富含AT的反向重复序列。删除该元件不会导致gutB的组成型表达。然而，诱导的gutB表达水平提高了三到四倍。
