影响 pSW200 和 ColE1 拷贝数和稳定性的序列。
A sequence that affects the copy number and stability of pSW200 and ColE1.
机构信息
Research Center for Bacterial Pathogenesis and Department of Microbiology and Immunology, Chang-Gung University, Kwei-Shan, Taoyuan 333, Taiwan.
出版信息
J Bacteriol. 2010 Jul;192(14):3654-60. doi: 10.1128/JB.00095-10. Epub 2010 May 21.
Pantoea stewartii SW2 contains 13 plasmids. One of these plasmids, pSW200, has a replicon that resembles that of ColE1. This study demonstrates that pSW200 contains a 9-bp UP element, 5'-AAGATCTTC, which is located immediately upstream of the -35 box in the RNAII promoter. A transcriptional fusion study reveals that substituting this 9-bp sequence reduces the activity of the RNAII promoter by 78%. The same mutation also reduced the number of plasmid copies from 13 to 5, as well as the plasmid stability. When a similar sequence in a ColE1 derivative, pYCW301, is mutated, the copy number of the plasmid also declines from 34 to 16 per cell. Additionally, inserting this 9-bp sequence stabilizes an unstable pSW100 derivative, pSW142K, which also contains a replicon resembling that of ColE1, indicating the importance of this sequence in maintaining the stability of the plasmid. In conclusion, the 9-bp sequence upstream of the -35 box in the RNAII promoter is required for the efficient synthesis of RNAII and maintenance of the stability of the plasmids in the ColE1 family.
斯图尔特泛菌 SW2 含有 13 个质粒。其中一个质粒 pSW200 的复制子类似于 ColE1。本研究表明，pSW200 含有一个 9 个碱基的 UP 元件，5'-AAGATCTTC，位于 RNAII 启动子的-35 框上游。转录融合研究表明，该 9 个碱基序列的替换使 RNAII 启动子的活性降低了 78%。同样的突变还将质粒拷贝数从 13 减少到 5，同时也降低了质粒的稳定性。当 ColE1 衍生物 pYCW301 中的类似序列发生突变时，质粒的拷贝数也从每个细胞 34 个下降到 16 个。此外，插入该 9 个碱基序列可稳定不稳定的 pSW100 衍生物 pSW142K，其也含有类似于 ColE1 的复制子，表明该序列在维持 ColE1 家族质粒的稳定性方面具有重要意义。总之，RNAII 启动子-35 框上游的 9 个碱基序列对于 RNAII 的高效合成和 ColE1 家族质粒的稳定性维持是必需的。
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