Department of Food Science, Cornell University, 352 Stocking Hall Ithaca, NY 14853, USA.
FEMS Microbiol Lett. 2020 Dec 14;367(22). doi: 10.1093/femsle/fnaa193.
The transcriptional activator Positive Regulatory Factor A (PrfA) regulates expression of genes essential for virulence in Listeria monocytogenes. To define the PrfA regulon, the 10403S wildtype (WT) strain, a constitutively active prfA* mutant, and an isogenic ∆prfA mutant were grown under PrfA-inducing conditions in a medium containing glucose-1-phosphate and pre-treated with 0.2% activated charcoal. RNA-seq-generated transcript levels were compared as follows: (i) prfA* and WT; (ii) WT and ∆prfA and (iii) prfA* and ∆prfA. Significantly higher transcript levels in the induced WT or constitutively active PrfA* were identified for 18 genes and 2 ncRNAs in at least one of the three comparisons. These genes included: (i) 10/12 of the genes previously identified as directly PrfA-regulated; (ii) 2 genes previously identified as PrfA-regulated, albeit likely indirectly; and (iii) 6 genes newly identified as PrfA-regulated, including one (LMRG_0 2046) with a σA-dependent promoter and PrfA box located within an upstream open reading frame. LMRG_0 2046, which encodes a putative cyanate permease, is reported to be downregulated by a σB-dependent anti-sense RNA. This newly identified overlap between the σB and PrfA regulons highlights the complexity of regulatory networks important for fine-tuning bacterial gene expression in response to the rapidly changing environmental conditions associated with infection.
转录激活因子 Positive Regulatory Factor A（PrfA）调节李斯特菌属中毒力所必需的基因的表达。为了定义 PrfA 调控组，在含有葡萄糖-1-磷酸的培养基中，在 PrfA 诱导条件下，对野生型（WT）10403S 菌株、组成型激活的 prfA突变株和同源缺失 prfA 突变株进行培养，并预先用 0.2%活化炭处理。将以下三种情况的 RNA-seq 生成的转录水平进行比较：（i）prfA和 WT；（ii）WT 和 ∆prfA；（iii）prfA和 ∆prfA。在至少一种比较中，诱导型 WT 或组成型激活的 PrfA的转录水平显著升高，有 18 个基因和 2 个 ncRNA。这些基因包括：（i）先前确定的 10/12 个直接受 PrfA 调控的基因；（ii）先前确定的 2 个受 PrfA 调控的基因，尽管可能是间接调控；（iii）新确定的 6 个受 PrfA 调控的基因，包括一个（LMRG_0 2046），其具有一个 σA 依赖性启动子和 PrfA 盒位于上游开放阅读框内。LMRG_0 2046 编码一种假定的氰酸盐通透酶，据报道，它受 σB 依赖性反义 RNA 下调。新发现的 σB 和 PrfA 调控组之间的这种重叠突出了调节网络的复杂性，这些网络对于精细调节细菌基因表达以响应与感染相关的快速变化的环境条件非常重要。
