0000000000698965
AUTHOR
Duarte Guerreiro
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…
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…