LASR OF PSEUDOMONAS-AERUGINOSA IS A TRANSCRIPTIONAL ACTIVATOR OF THE ALKALINE PROTEASE GENE (APR) AND AN ENHANCER OF EXOTOXIN-A EXPRESSION
LASR OF PSEUDOMONAS-AERUGINOSA IS A TRANSCRIPTIONAL ACTIVATOR OF THE ALKALINE PROTEASE GENE (APR) AND AN ENHANCER OF EXOTOXIN-A EXPRESSION
复制标题
DOI：
10.1128/iai.61.4.1180-1184.1993
复制
发表时间：
1993-04-01
影响因子：
3.1
通讯作者：
IGLEWSKI, BH
中科院分区：
文献类型：
--
作者：
GAMBELLO, MJ;KAYE, S;IGLEWSKI, BH
铜绿假单胞菌的 lasR 基因是弹性蛋白酶 (lasB) 和 Las.A 蛋白酶 (lasA) 基因转录所必需的，这两种蛋白酶与毒力相关。我们在此报道碱性蛋白酶基因（apr）也需要 lasR 基因进行转录。根据 Northern (RNA) 分析确定，lasR 突变体 PAO-R1 中不存在碱性蛋白酶 mRNA，而当以反式提供完整的 lasR 基因时，则存在碱性蛋白酶 mRNA。 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 上清液中的外毒素 A 活性低 30%。 PAO-R1 中反式 lasR 的多个拷贝将毒素 A 活性提高至亲本水平的两倍。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 在 toxA 启动子或上游 toxA mRNA 序列上起作用。 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启动子的影响并不是由于刺激了regA（toxA的转录激活因子）的转录。含有转录 regA 启动子-CAT 基因融合体的 PAO-SR 和 PAO-R1 之间的氯霉素乙酰转移酶 (CAT) 活性没有差异。这些结果扩大了 lasR 的调控范围，表明 lasR 基因在铜绿假单胞菌发病机制中发挥着全局作用。
The lasR gene of Pseudomonas aeruginosa is required for transcription of the genes for elastase (lasB) and Las.A 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 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.