Mojumdar M, Khan S A
Department of Microbiology, School of Medicine, University of Pittsburgh, Pennsylvania 15261.
J Bacteriol. 1988 Dec;170(12):5522-8. doi: 10.1128/jb.170.12.5522-5528.1988.
Some genetic and biochemical properties of the tetracycline resistance element of the Staphylococcus aureus plasmid pT181 have been studied. Resequencing of a portion of the tetracycline resistance gene (tet) showed the presence of a single open reading frame of 1,299 nucleotides capable of encoding a polypeptide of 433 amino acids. Analysis of BAL 31 nuclease-generated deletion mutants of the tet gene showed the presence of two complementation groups within this region. Northern blot hybridizations demonstrated that the tet gene encodes a single mRNA, and its initiation site has been mapped by S1 nuclease protection experiments. We also identified an approximately 52,000-dalton tetracycline-inducible polypeptide in Bacillus subtilis minicells carrying pT181. Induction of the tet gene by tetracycline resulted in a 4-fold increase in the levels of TET mRNA and at least a 15-fold increase in the amount of TET protein in B. subtilis minicells.
对金黄色葡萄球菌质粒pT181的四环素抗性元件的一些遗传和生化特性进行了研究。对四环素抗性基因（tet）的一部分进行重新测序，结果显示存在一个1299个核苷酸的单一开放阅读框，能够编码一个由433个氨基酸组成的多肽。对BAL 31核酸酶产生的tet基因缺失突变体的分析表明，该区域内存在两个互补组。Northern印迹杂交表明tet基因编码单一的mRNA，其起始位点已通过S1核酸酶保护实验进行了定位。我们还在携带pT181的枯草芽孢杆菌小细胞中鉴定出一种约52,000道尔顿的四环素诱导多肽。四环素对tet基因的诱导导致枯草芽孢杆菌小细胞中TET mRNA水平增加4倍，TET蛋白量至少增加15倍。
