丰富的尿氨基酸通过两种不同的机制在大肠杆菌中激活编码谷氨胺合成酶glnA

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Updated: Jul 3, 2025

Glutamine Flux Imaging Using Genetically Encoded Sensors

Glutamine Flux Imaging Using Genetically Encoded Sensors

Published on: July 31, 2014

Karthik Urs¹, Philippe E Zimmern², Larry Reitzer¹

¹Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA.

Journal of bacteriology

|February 15, 2024

概括

尿路病原性大肠杆菌在尿液中产生了对谷氨酸合成酶 (GS) 的未翻译转录,这是由于氨基酸和尿素的丰富性. 这挑战了细菌的生长,表明了尿路感染的潜在治疗点.

科学领域:

微生物学微生物学
分子生物学分子生物学
细菌病原体的产生

背景情况:

尿病原性大肠杆菌 (UPEC) 在膀中的生长会诱导氨酸同化谷氨胺合成酶 (GS) 基因 (glnA).
尿液中的尿素通常通过CRP依赖的glnAp1促进体诱导glnA转录,但这种转录不会被翻译.
众所周知,大量的尿氨基酸在体外抑制了GS活性.

研究的目的:

为了调查大量的尿氨基酸是否会在体内影响glnA转录.
了解尿路感染期间在UPEC中glnA转录和翻译的调节.

主要方法:

使用具有crp和glnG缺失的突变菌株,分别从glnAp2和glnAp1促进器强制转录.
使用glnA-gfp转录融合和定量逆转录PCR来监测glnA转录.
评估了使用glnA-gfp转化融合,酶分析和西式涂抹的GS蛋白质生产.

主要成果:

丰富的氨基酸损害了细菌生长,由谷氨酸和谷氨酸逆转,表明GS抑制.
氨基酸刺激了没有尿素的glnAp2转录,以及用尿素的glnAp1转录.
在尿素的存在下从glnAp1转录并没有产生可翻译的mRNA或可检测的GS蛋白.

结论:

丰富的尿氨基酸放大尿素的作用,导致从glnAp1的超转录,但是一个未翻译的转录.
为了在尿液中快速增长,UPEC必须克服这种对谷氨胺合成的阻碍.
了解这些调节机制和潜在的绕道策略可能会揭示尿路感染的新型治疗点.

关键词:

埃舍里希亚大肠杆菌 (Escherichia coli) 是一个大肠杆菌.谷氨胺合成酶的使用尿路感染尿路感染尿液的组成尿液的组成

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