Jasiecki Jacek, Wegrzyn Grzegorz
Department of Molecular Biology, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland.
Plasmid. 2006 Mar;55(2):169-72. doi: 10.1016/j.plasmid.2005.10.002. Epub 2005 Dec 2.
Escherichia coli pcnB gene was discovered as a regulator of ColE1 plasmid copy number about 20 years ago. Further studies indicated that this gene codes for poly(A) polymerase I (PAP I). However, although importance of RNA polyadenylation has been demonstrated and biochemical properties of PAP I have been studied extensively, little is known about regulation of the pcnB gene transcription. Here, we demonstrate that there are three transcription start sites upstream of the pcnB coding sequence. Activities of at least two of these promoters were in inverse correlation to bacterial growth rates, which agrees with recently published results indicating increased abundance of PAP I and higher levels of RNA polyadenylation in slowly growing bacteria.
大约20年前，大肠杆菌的pcnB基因作为ColE1质粒拷贝数的调节因子被发现。进一步研究表明，该基因编码聚腺苷酸聚合酶I（PAP I）。然而，尽管RNA聚腺苷酸化的重要性已得到证实，并且对PAP I的生化特性也进行了广泛研究，但关于pcnB基因转录的调控却知之甚少。在此，我们证明在pcnB编码序列上游存在三个转录起始位点。其中至少两个启动子的活性与细菌生长速率呈负相关，这与最近发表的结果一致，即表明在生长缓慢的细菌中PAP I丰度增加且RNA聚腺苷酸化水平更高。
