Regulation of Escherichia coli fim gene transcription by GadE and other acid tolerance gene products.
Regulation of Escherichia coli fim gene transcription by GadE and other acid tolerance gene products.
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GadE 和其他耐酸基因产物对大肠杆菌 fim 基因转录的调节。
DOI：
10.1099/mic.0.001149
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Wolchak,Robert
中科院分区：
文献类型：
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作者：
Schwan,WilliamR;Luedtke,Joshua;Engelbrecht,Kathleen;Mollinger,Jeremy;Wheaton,Andrew;Foster,JohnW;Wolchak,Robert
尿路致病性大肠杆菌（UPEC）每年在美国引起数百万例尿路感染。1型皮利对于UPEC粘附于渗透压和pH变化的人和鼠尿路中的尿路上皮细胞是重要的。先前的工作已经表明，酸性pH不利地影响1型皮利的表达。为了确定耐酸性基因产物是否可以调节E. colifim基因的表达，用单拷贝质粒上的fimA-lux、fimB-lux和fimE-lux融合体筛选K-12菌株耐酸基因突变体库。我们已经确定，一个突变的GadE增加了所有三个fim基因的转录，这表明GadE可能是作为一个阻遏物在低pH环境。gadE突变的互补使fim基因转录恢复到野生型水平。此外，adX、gadW、crp和cya的突变也影响了三个fim基因的转录。为了验证GadE在1型菌毛表达中的作用，测试了NU 149 gadEUPEC菌株。与野生型细菌相比，在低pH培养基中培养的菌株NU 149 gadE中，gadE突变体具有更高的fimE基因转录水平，更高频率的FimS的Phase-OFF定位，以及更低的血凝滴度。数据表明，UPEC fim基因直接或间接受GADE蛋白的调节，这可能对通过酸化尿液和关闭fim基因表达来预防尿路感染的能力具有一定的未来影响。
UropathogenicEscherichia coli(UPEC) cause millions of urinary tract infections each year in the United States. Type 1 pili are important for adherence of UPEC to uroepithelial cells in the human and murine urinary tracts where osmolality and pH vary. Previous work has shown that an acidic pH adversely affects the expression of type 1 pili. To determine if acid tolerance gene products may be regulatingE. coli fimgene expression, a bank of K-12 strain acid tolerance gene mutants were screened usingfimA-lux, fimB-lux, andfimE-luxfusions on single copy number plasmids. We have determined that a mutation ingadEincreased transcription of all threefimgenes, suggesting that GadE may be acting as a repressor in a low pH environment. Complementation of thegadEmutation restoredfimgene transcription to wild-type levels. Moreover, mutations ingadX, gadW, crp,andcyaalso affected transcription of the threefimgenes. To verify the role GadE plays in type 1 pilus expression, the NU149gadEUPEC strain was tested. ThegadEmutant had higherfimEgene transcript levels, a higher frequency of Phase-OFF positioning offimS, and hemagglutination titres that were lower in strain NU149gadEcultured in low pH medium as compared to the wild-type bacteria. The data demonstrate that UPECfimgenes are regulated directly or indirectly by the GadE protein and this could have some future bearing on the ability to prevent urinary tract infections by acidifying the urine and shutting offfimgene expression.