Abeles A L, Reaves L D, Austin S J
Laboratory of Chromosome Biology, National Cancer Institute-Frederick Cancer Research and Development Center, Maryland 21701.
J Bacteriol. 1990 Aug;172(8):4386-91. doi: 10.1128/jb.172.8.4386-4391.1990.
The P1 plasmid replication origin requires the host DnaA protein for function. Two DnaA-binding boxes lie in tandem within the previously defined minimal origin, constituting its left boundary. Three more boxes lie 200 base pairs to the right of these, in the leader region for the P1 repA gene. We show that either set alone is active for origin function. One of the two origin boxes is relatively inactive. Constructs with just one of the five boxes are active for specific origin function as long as the box conforms exactly to the published consensus. This single consensus box is functional when placed either to the left or right of the core origin sequences. The flexibility shown by this system suggests that the boxes play a role different from those in the host oriC origin, where the number and position of boxes are critical.
P1 质粒复制起点发挥功能需要宿主 DnaA 蛋白。在先前定义的最小起点内，两个 DnaA 结合框串联排列，构成其左边界。另外三个框位于这些框右侧 200 个碱基对处，在 P1 repA 基因的前导区域。我们表明，单独的任何一组框对于起点功能都是有活性的。两个起点框中的一个相对无活性。只要框与已发表的共有序列完全一致，仅包含五个框中的一个的构建体对于特定的起点功能就是有活性的。这个单一的共有框放置在核心起点序列的左侧或右侧时都具有功能。该系统所表现出的灵活性表明，这些框所起的作用与宿主 oriC 起点中的框不同，在宿主 oriC 起点中，框的数量和位置至关重要。
