Altered expression of the ToxR-regulated porins OmpU and OmpT diminishes Vibrio cholerae bile resistance, virulence factor expression, and intestinal colonization
Altered expression of the ToxR-regulated porins OmpU and OmpT diminishes Vibrio cholerae bile resistance, virulence factor expression, and intestinal colonization
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DOI：
10.1073/pnas.170219997
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发表时间：
2000-08-29
影响因子：
11.1
通讯作者：
Klose, KE
中科院分区：
文献类型：
--
作者：
Provenzano, D;Klose, KE
跨膜转录激活因子ToxR和TcpP通过控制toxT来调节霍乱弧菌毒力因子的表达，toxT编码ctx、tcp和acf毒力基因的胞质转录激活因子。然而，ToxR独立于TcpP和ToxT，激活和抑制编码两种外膜孔蛋白OmpU和OmpT的基因的转录。为了确定ToxR依赖性孔蛋白调节在霍乱弧菌发病机制中的作用，使用ToxR激活的OmpU启动子来驱动缺少OmpU的菌株中的OmpT转录。同样地，ToxR阻遏的ompT启动子用于在缺乏ToxR和OmpT的菌株中驱动ompU转录。该策略允许产生表达OmpT代替OmpU的toxR（+）菌株和表达OmpU代替OmpT的toxR（-）菌株。对于toxR（+）V，在胆汁盐和其它阴离子去污剂存在下的生长速率被延迟，此外，表达OmpT代替OmpU的toxR（+）霍乱弧菌表达较少的霍乱毒素和毒素共调节菌毛，并且这种效应显示是由该菌株中toxT转录减少引起的。最后，表达OmpT代替OmpU的toxR（+）V，cholesterol在幼鼠肠中定殖的能力降低了约100倍。我们的研究结果表明，外膜孔蛋白OmpU和OmpT的ToxR依赖性调节对于霍乱弧菌的胆汁抗性、毒力因子表达和肠道定植至关重要。
The transmembrane transcriptional activators ToxR and TcpP modulate expression of Vibrio cholerae virulence factors by exerting control over toxT, which encodes the cytoplasmic transcriptional activator of the ctx, tcp, and acf virulence genes. However, ToxR, independently of TcpP and ToxT, activates and represses transcription of the genes encoding two outer-membrane porins, OmpU and OmpT, To determine the role of ToxR-dependent porin regulation in V. cholerae pathogenesis, the ToxR-activated ompU promoter was used to drive ompT transcription in a strain lacking OmpU. Likewise, the ToxR-repressed ompT promoter was used to drive ompU transcription in a strain lacking both ToxR and OmpT, This strategy allowed the generation of a toxR(+) strain that expresses OmpT in place of OmpU, and a toxR(-) strain that expresses OmpU in place of OmpT, Growth rates in the presence of bile salts and other anionic detergents were retarded for the toxR(+) V, cholerae expressing OmpT in place of OmpU, but increased in toxR(-) V. cholerae expressing OmpU in place of OmpT, Additionally, the toxR(+) V. cholerae expressing OmpT in place of OmpU expressed less cholera toxin and toxin-coregulated pilus, and this effect was shown to be caused by reduced toxT transcription in this strain, Finally, the toxR(+) V, cholerae expressing OmpT in place of OmpU was approximate to 100-fold reduced in its ability to colonize the infant-mouse intestine. Our results indicate that ToxR-dependent modulation of the outer membrane porins OmpU and OmpT is critical for V. cholerae bile resistance, virulence factor expression, and intestinal colonization.