Transcriptional profiling of theL. monocytogenesPrfA regulon identifies six novel putative PrfA-regulated genes

Abstract

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_02046) with a σA-dependent promoter and PrfA box located within an upstream open reading frame. LMRG_02046, 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.

Frecuencia Del Grupo Escape en Heridas en Pacientes De Un Hospital Del Estado De Puebla, México

“…A nivel postranscripcional, la actividad de la PrfA se ve influenciada por una serie de factores ambientales y estados fisiológicos, como la presencia de carbohidratos fermentables, estado intracelular, crecimiento en medio mínimo y la entrada en la fase estacionaria (Vera et al, 2013). Sin embargo, es importante mencionar que el factor sigma alternativo σ B responde al estrés y desempeña un papel importante en la regulación de la expresión génica durante la infección, incluso a través de la corregulación de varios genes dependientes de σ B y PrfA (Henderson et al, 2020).…”

Anti-infective activities of long-chain fatty acids against foodborne pathogens

“…Intriguingly, a Δ prfA mutant strain can grow at high concentrations of medium- and long-chain FFAs, suggesting that unknown regulatory activities of PrfA increases the sensitivity of L. monocytogenes toward antimicrobial FFAs (Sternkopf Lillebaek et al 2017 ). Indeed, in addition to the PrfA-dependent virulence genes described above, PrfA is known to control the expression of multiple genes involved in stress tolerance and general metabolism (Milohanic et al 2003 , Marr et al 2006 , Henderson et al 2020 ). Clearly, PrfA plays a central role in the response of L. monocytogenes against antimicrobial and antivirulent medium- and long-chain FFAs (Sternkopf Lillebaek et al 2017 , Dos Santos et al 2020 ).…”

Transcription of Listeria monocytogenes Key Virulence Genes on Tomato, Cucumber and Carrot

“…The latter encodes PrfA that directly regulates transcription of twelve key virulence genes and indirectly a total of 145 genes. Thus, it possesses a key role in directing cellular homeostasis and fine-tuning the virulence machinery of L. monocytogenes [7].…”