Control of virulence gene expression in Bacillus anthracis.
Control of virulence gene expression in Bacillus anthracis.
复制标题
炭疽杆菌毒力基因表达的控制。
DOI：
10.1046/j.1365-2672.1999.00887.x
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发表时间：
1999
影响因子：
4
通讯作者：
Koehler,TM
中科院分区：
文献类型：
--
作者：
Hoffmaster,AR;Koehler,TM
atxA基因是炭疽芽孢杆菌毒力基因表达的重要调控因子，它正调控编码炭疽毒素蛋白的三个基因的表达，并且至少有一个基因是产生荚膜所必需的。在这里，我们报告anatxA-null突变体表现出与毒素和胶囊合成无关的表型。AnatxA-无效突变体在基本培养基上生长不良，并且比亲本菌株更有效地形成孢子。许多转座子产生的启动子lacZ融合在pXO 1上的不同位点表现出CO2增强的datxA依赖性表达，与毒素基因观察到的相似。我们还报道了该xA激活的pagA基因（编码保护性抗原毒素蛋白）与位于pagA下游的300 bp基因pagR共转录。预测的pagR蛋白产物与其他生物体中的转录调控因子具有一定的氨基酸序列相似性。我们的数据表明，pagR抑制pagA和atxA的表达。pagR还控制pXO 1上一些CO2/atxA激活的转录融合体的表达，这些融合体与毒素基因不对应。这些融合体和pagA和pagR的调节可能是由于atxA水平的变化，或者可能是独立于atxA表达。
TheatxAgene is an important regulator of virulence gene expression inBacillus anthracis.atxApositively regulates expression of the three genes encoding the anthrax toxin proteins and at least one gene is required for capsule production. Here we report that anatxA‐null mutant exhibits phenotypes unrelated to toxin and capsule synthesis. AnatxA‐null mutant grows poorly on minimal media and sporulates more efficiently than the parent strain. Numerous transposon‐generated promoter‐lacZfusions at distinct loci on pXO1 exhibit CO2‐enhancedatxA‐dependent expression similar to that observed for the toxin genes. We also report that theatxA‐activatedpagAgene (encoding the protective antigen toxin protein) is co‐transcribed with a 300‐bp gene,pagR, located downstream ofpagA. The predicted protein product ofpagRhas some amino acid sequence similarity to transcriptional regulators in other organisms. Our data indicate thatpagRrepresses expression ofpagAandatxA.pagRalso controls expression of some CO2/atxA‐activated transcriptional fusions on pXO1 that do not correspond to the toxin genes. Regulation of these fusions andpagAandpagRmay be due to changes in AtxA levels, or may be independent ofatxAexpression.