School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
Biochem J. 2012 Jan 1;441(1):481-5. doi: 10.1042/BJ20111258.
In the present paper, we report that transcription affects the location of a DNA target in Escherichia coli K-12. A strain whose chromosome had been engineered to encode a lac repressor-GFP (green fluorescent protein) fusion was used as a host for a low copy number plasmid that carries an array of five lac operator sites. Individual cells of this strain exhibited a diffuse fluorescence signal, suggesting that the plasmid is distributed throughout the cell cytoplasm. However, a derivative of this plasmid carrying a cloned constitutive promoter is targeted to a location at the edge of the nucleoid towards the pole of the host cell. We conclude that transcription from the cloned promoter is driving the location of the plasmid and that specific locations in bacterial cells may favour gene expression.
在本研究中，我们报道转录会影响大肠杆菌 K-12 中 DNA 靶标的位置。我们以一株经过工程改造使其染色体编码 lac 阻遏物-GFP（绿色荧光蛋白）融合蛋白的菌株作为宿主，使用带有 5 个 lac 操纵子位点的低拷贝数质粒。该菌株的单个细胞表现出弥散的荧光信号，表明质粒分布在整个细胞质中。然而，该质粒的一个衍生质粒，携带克隆的组成型启动子，被靶向到位于宿主细胞边缘朝向极点的核区位置。我们的结论是，来自克隆启动子的转录驱动了质粒的定位，而细菌细胞中的特定位置可能有利于基因表达。
