Autoregulation of the Pseudomonas aeruginosa protein PtxS occurs through a specific operator site within the ptxS upstream region.
Autoregulation of the Pseudomonas aeruginosa protein PtxS occurs through a specific operator site within the ptxS upstream region.
复制标题
铜绿假单胞菌蛋白 PtxS 的自动调节是通过 ptxS 上游区域内的特定操纵位点发生的。
DOI：
10.1128/jb.182.15.4366-4371.2000
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发表时间：
2000
影响因子：
3.2
通讯作者：
Hamood,AN
中科院分区：
文献类型：
--
作者：
Swanson,BL;Hamood,AN
我们先前已经证明，铜绿假单胞菌toxA调节蛋白PtxS通过与一个52 bp的片段结合来自动调节其自身的合成。该片段的3′端位于ptxS翻译起始位点的5′端58 bp处。我们已经确定了一个14 bp的回文序列（TGAAACCGGTTTCA）内的52 bp的片段。在这项研究中，我们使用定点突变和启动子融合实验，以确定是否PtxS特异性结合到这个回文序列和regulatesptxS表达。我们还试图确定在PtxS结合和PtxS表达的回文序列内的特定核苷酸的作用。最初的启动子融合实验证实，52 bp的片段不重叠的区域进行theptxS启动子活性。从52-bp片段中删除14-bp回文序列后，PtxS结合被消除。此外，14 bp序列的缺失导致P.产气荚膜梭菌PAO 1和ptxS等基因突变株PAO：：ptxS。14-bp序列内特定核苷酸的突变消除、减少或对PtxS结合没有影响。然而，这些核苷酸中的几个突变在PAO 1和PAO：：ptxS中产生ptxS表达的显著增加。这些结果表明：（i）14-bp回文序列和其中的特定核苷酸在PtxS结合中起作用;（ii）回文序列的缺失或其中某些核苷酸的改变干扰了可能调节PtxS表达的另一种机制。
We have previously shown that thePseudomonas aeruginosa toxAregulatory protein PtxS autoregulates its own synthesis by binding to a 52-bp fragment. The 3′ end of the 52-bp fragment is located 58 bp 5′ of theptxStranslation start site. We have identified a 14-bp palindromic sequence (TGAAACCGGTTTCA) within the 52-bp fragment. In this study, we used site-directed mutagenesis and promoter fusion experiments to determine if PtxS binds specifically to this palindromic sequence and regulatesptxSexpression. We have also tried to determine the roles of specific nucleotides within the palindromic sequence in PtxS binding andptxSexpression. Initial promoter fusion experiments confirmed that the 52-bp fragment does not overlap with the region that carries theptxSpromoter activity. PtxS binding was eliminated upon the deletion of the 14-bp palindromic sequence from the 52-bp fragment. In addition, the deletion of the 14-bp sequence caused a significant enhancement inptxSexpression in theP. aeruginosastrain PAO1 and theptxSisogenic mutant PAO::ptxS. Mutation of specific nucleotides within the 14-bp sequence eliminated, reduced, or had no effect on PtxS binding. However, mutations of several of these nucleotides produced a significant increase inptxSexpression in both PAO1 and PAO::ptxS. These results suggest that (i) the 14-bp palindromic sequence and specific nucleotides within it play a role in PtxS binding and (ii) deletion of the palindromic sequence or changing of certain nucleotides within it interferes with another mechanism that may regulateptxSexpression.