0000000001299603
AUTHOR
Jörgen Johansson
Frequent emergence of sigB mutant alleles in Listeria monocytogenes is likely to be linked to a growth advantage at elevated temperatures
International audience; Background: The food-borne pathogen Listeria monocytogenes is a Gram-positive bacteria and highly resistant to a variety of stresses. Such resistance is determinate by the activation of the alternative sigma factor B (σB). Genes within sigB operon encode for the signal transduction that controls σB activity. Mutations within this operon generally result on reduced σB activation. Objectives: Characterize the impact of secondary mutations within L. monocytogenes sigB operon, and identify laboratory conditions that promote the selection of such mutations among wild type (WT) populations. Methods: Transposon mutants (Tms) that lost the ability to form rings in response t…
The σ B -dependent regulatory sRNA Rli47 represses isoleucine biosynthesis in Listeria monocytogenes through a direct interaction with the ilvA transcript
International audience; The facultative intracellular pathogen Listeria monocytogenes can persist and grow in a diverse range of environmental conditions, both outside and within its mammalian host. The alternative sigma factor Sigma B (sigma(B)) plays an important role in this adaptability and is critical for the transition into the host. While some of the functions of the sigma(B) regulon in facilitating this transition are understood the role of sigma(B)-dependent small regulatory RNAs (sRNAs) remain poorly characterized. In this study, we focused on elucidating the function of Rli47, a sigma(B)-dependent sRNA that is highly induced in the intestine and in macrophages. Using a combinatio…
Sigma B-dependent regulatory sRNA Rli47 represses isoleucine biosynthesis in Listeria monocytogenes
International audience; Background: Small regulatory RNAs (sRNAs) can influence cellular processes by targeting mRNAs, leading to translation inhibition and mRNA degradation. Previous studies have shown that the σB-dependent sRNA Rli47 is induced in L. monocytogenes stationary phase cells, in the intestinal lumen and macrophages, but its function has remained elusive. Objectives: This study aimed to comprehensively characterize Rli47 and determine its biological function in L. monocytogenes. Methods: Besides in silico predictions, several molecular approaches such as DMS-MaPseq, northern blotting, EMSAs, RTqPCR, RNA-seq and phenotypic experiments were applied. Results: Rli47 was shown to ba…
The σB-dependent regulatory sRNA Rli47 represses isoleucine biosynthesis in Listeria monocytogenes through a direct interaction with the ilvA transcript
The facultative intracellular pathogen Listeria monocytogenes can persist and grow in a diverse range of environmental conditions, both outside and within its mammalian host. The alternative sigma factor Sigma B (σB) plays an important role in this adaptability and is critical for the transition into the host. While some of the functions of the σB regulon in facilitating this transition are understood the role of σB-dependent small regulatory RNAs (sRNAs) remain poorly characterized. In this study, we focused on elucidating the function of Rli47, a σB-dependent sRNA that is highly induced in the intestine and in macrophages. Using a combination of in silico and in vivo approaches, a binding…