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首页> 外文期刊>Infection and immunity >LasR of Pseudomonas aeruginosa is a transcriptional activator of the alkaline protease gene (apr) and an enhancer of exotoxin A expression.
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LasR of Pseudomonas aeruginosa is a transcriptional activator of the alkaline protease gene (apr) and an enhancer of exotoxin A expression.

机译：铜绿假单胞菌的LasR是碱性蛋白酶基因（apr）的转录激活因子，也是外毒素A表达的增强子。

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The lasR gene of Pseudomonas aeruginosa is required for transcription of the genes for elastase (lasB) and LasA protease (lasA), two proteases associated with virulence. We report here that the alkaline protease gene (apr) also requires the lasR gene for transcription. Alkaline protease mRNA was absent in the lasR mutant PAO-R1 and present when an intact lasR gene was supplied in trans as determined by Northern (RNA) analysis. The lasR gene also enhances exotoxin A production. Exotoxin A activity in supernatants of PAO-R1 were 30% less than in supernatants of the parental strain, PAO-SR. Multiple copies of lasR in trans in PAO-R1 in increased toxin A activity to twice the parental levels. Analysis of PAO-R1 containing the toxA promoter fused to beta-galactosidase suggests that LasR acts at the toxA promoter or at upstream toxA mRNA sequences. beta-Galactosidase activity was approximately 40% lower in PAO-R1 than in the parental strain, PAO-SR. Furthermore, the effect of LasR on the toxA promoter is not due to the stimulation of transcription of regA, a transcriptional activator of toxA. No difference in chloramphenicol acetyltransferase (CAT) activity was noted between PAO-SR and PAO-R1 containing transcriptional regA promoter-CAT gene fusions. These results broaden the regulatory dominion of lasR and suggest that the lasR gene plays a global role in P. aeruginosa pathogenesis.
机译：铜绿假单胞菌的lasR基因是弹性蛋白酶（lasB）和LasA蛋白酶（lasA）（与毒力相关的两种蛋白酶）的基因转录所必需的。我们在这里报告碱性蛋白酶基因（apr）也需要lasR基因进行转录。碱性蛋白酶mRNA在lasR突变体PAO-R1中不存在，当通过Northern（RNA）分析确定反式提供完整的lasR基因时，碱性蛋白酶存在。 lasR基因还可以增强外毒素A的产生。 PAO-R1上清液中的外毒素A活性比亲本菌株PAO-SR的上清液低30％。 PAO-R1中反式的lasR的多个副本使毒素A活性增加至亲本水平的两倍。对含有与β-半乳糖苷酶融合的toxA启动子的PAO-R1的分析表明，LasR作用于toxA启动子或上游toxA mRNA序列。 PAO-R1中的β-半乳糖苷酶活性比亲本菌株PAO-SR低约40％。此外，LasR对toxA启动子的作用不是由于刺激regA（toxA的转录激活因子）的转录。在PAO-SR和含有转录regA启动子-CAT基因融合体的PAO-R1之间，氯霉素乙酰转移酶（CAT）活性未见差异。这些结果扩大了lasR的调控作用，并表明lasR基因在铜绿假单胞菌的发病机理中起着整体作用。

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