Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal (QC), H3T 1J4, Canada.
Microbiology (Reading). 2021 Mar;167(3). doi: 10.1099/mic.0.001022. Epub 2021 Jan 21.
The serovar Typhi genome contains 14 putative fimbrial systems. The Std fimbriae belong to the chaperone-usher family and its regulation has not been investigated in . Typhi. Several regulators of Std were previously identified in the closely related serovar Typhimurium. We hypothesize that regulators of . Typhimurium may be shared with . Typhi, but that several other regulators remain to be discovered. Here, we describe the role of more than 50 different candidate regulators on expression. Three types of regulators were investigated: known regulators in . Typhimurium, predicted regulators and virulence/metabolic regulators. Expression of was determined in the regulator mutants and compared with the wild-type strain. Overall, 21 regulator mutations affect promoter expression. The role of Crp, a newly identified factor for expression, was further investigated. Crp acted as an activator of expression on a distal region of the promoter region. Together, our results demonstrate the major influence of Crp as a novel transcriptional factor on promoter expression and later production of Std fimbriae in .
伤寒血清型基因组包含 14 个假定的菌毛系统。Std 菌毛属于伴侣-usher 家族，其调节尚未在伤寒血清型中进行研究。在密切相关的血清型鼠伤寒菌中，先前已经鉴定出几个 Std 的调节因子。我们假设鼠伤寒菌的调节因子可能与伤寒血清型共享，但仍有几个其他调节因子有待发现。在这里，我们描述了 50 多个不同候选调节因子对 表达的作用。研究了三种类型的调节剂：鼠伤寒菌中的已知调节剂、预测调节剂和毒力/代谢调节剂。在调节剂突变体中测定了 的表达，并与野生型菌株进行了比较。总的来说，21 个调节突变影响 启动子的表达。进一步研究了 Crp 对 表达的作用，Crp 是 表达的一个新发现的因子。Crp 作为一个新的转录因子在 启动子区域的远端区域激活 表达。总之，我们的结果表明 Crp 作为一个新的转录因子对 启动子表达和随后 Std 菌毛产生的主要影响。
