yqhG Contributes to Oxidative Stress Resistance and Virulence of Uropathogenic Escherichia coli and Identification of Other Genes Altering Expression of Type 1 Fimbriae
yqhG Contributes to Oxidative Stress Resistance and Virulence of Uropathogenic Escherichia coli and Identification of Other Genes Altering Expression of Type 1 Fimbriae
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DOI：
10.3389/fcimb.2019.00312
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发表时间：
2019-08-29
影响因子：
5.7
通讯作者：
Dozois, Charles M.
中科院分区：
文献类型：
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作者：
Bessaiah, Hicham;Pokharel, Pravil;Dozois, Charles M.
尿路感染（UTI）是常见的细菌感染，并且绝大多数UTI由肠外致病性大肠杆菌（ExPEC）菌株引起，所述肠外致病性大肠杆菌（ExPEC）菌株被称为尿路致病性大肠杆菌。大肠杆菌（UPEC）。UPEC在人类尿路的成功定植是由分泌的或表面暴露的毒力因子-毒素、铁转运系统和粘附素（例如1型菌毛（皮利））介导的。为了鉴定参与1型菌毛表达的因子，我们构建了由菌毛启动子区fimS控制下的lux组成的染色体转录报告基因，并将该构建体插入参考UPEC菌株CFT 073基因组的attTn 7位点。该fimS报告菌株用于产生Tn 10转座子突变体文库，结合高通量测序以鉴定影响1型菌毛表达的基因。转座子插入位点与参与蛋白质命运和合成、能量代谢、粘附、转录调控和运输的基因相关联。我们发现，YqhG，一个预测的周质蛋白，是一个重要的介质，有助于减少表达的1型菌毛在UPEC菌株CFT 073。Δ yqhG突变体具有降低的1型菌毛表达和降低的定殖小鼠泌尿道的能力。1型菌毛的表达减少与在OFF位置的fim开关的方向的偏置增加相关。有趣的是，Δ yqhG突变体比WT菌株更能动，并且对过氧化氢也显著更敏感。两者合计，yqhG的损失可能会降低在泌尿道中的毒力，由于1型菌毛的生产减少和更大的敏感性氧化应激。
Urinary tract infections (UTIs) are common bacterial infections and the vast majority of UTIs are caused by extraintestinal pathogenic Escherichia coli (ExPEC) strains referred to as uropathogenic E. coli (UPEC). Successful colonization of the human urinary tract by UPEC is mediated by secreted or surface exposed virulence factors-toxins, iron transport systems, and adhesins, such as type 1 fimbriae (pili). To identify factors involved in the expression of type 1 fimbriae, we constructed a chromosomal transcriptional reporter consisting of lux under the control of the fimbrial promoter region, fimS and this construct was inserted into the reference UPEC strain CFT073 genome at the attTn7 site. This fimS reporter strain was used to generate a Tn10 transposon mutant library, coupled with high-throughput sequencing to identify genes that affect the expression of type 1 fimbriae. Transposon insertion sites were linked to genes involved in protein fate and synthesis, energy metabolism, adherence, transcriptional regulation, and transport. We showed that YqhG, a predicted periplasmic protein, is one of the important mediators that contribute to the decreased expression of type 1 fimbriae in UPEC strain CFT073. The Delta yqhG mutant had reduced expression of type 1 fimbriae and a decreased capacity to colonize the murine urinary tract. Reduced expression of type 1 fimbriae correlated with an increased bias for orientation of the fim switch in the OFF position. Interestingly, the Delta yqhG mutant was more motile than the WT strain and was also significantly more sensitive to hydrogen peroxide. Taken together, loss of yqhG may decrease virulence in the urinary tract due to a decrease in production of type 1 fimbriae and a greater sensitivity to oxidative stress.