Endoribonuclease-mediated control of hns mRNA stability constitutes a key regulatory pathway for Salmonella Typhimurium pathogenicity island 1 expression

Abstract

Bacteria utilize endoribonuclease-mediated RNA processing and decay to rapidly adapt to environmental changes. Here, we report that the modulation of hns mRNA stability by the endoribonuclease RNase G plays a key role in Salmonella Typhimurium pathogenicity. We found that RNase G determines the half-life of hns mRNA by cleaving its 5′ untranslated region and that altering its cleavage sites by genome editing stabilizes hns mRNA, thus decreasing S. Typhimurium virulence in mice. Under anaerobic conditions, the FNR-mediated transcriptional repression of rnc encoding RNase III, which degrades rng mRNA, and simultaneous induction of rng transcription resulted in rapid hns mRNA degradation, leading to the derepression of genes involved in the Salmonella pathogenicity island 1 (SPI-1) type III secretion system (T3SS). Together, our findings show that RNase III and RNase G levels-mediated control of hns mRNA abundance acts as a regulatory pathway upstream of a complex feed-forward loop for SPI-1 expression.

Identification of the global regulatory roles of RraA via the integrative transcriptome and proteome in Vibrio alginolyticus

“…It was reported that the deletion of rraA resulted in reduced motility in V. vulnificus and Salmonella Typhimurium ( 12 , 31 ). However, no significant impact on motility was observed for V. alginolyticus .…”

CRISPR-Cas9-assisted genome editing inE. colielevates the frequency of unintended mutations

“…Cas9-assisted editing in bacteria has been used to assess the phenotypic effects of individual point mutations (32) and of more extensive edits such as modification of ribosomes (33), introduction of genes encoding new metabolic pathways (34)(35)(36)(37)(38) and deletion of virulence genes (1,39). Additionally, creation of large mutant libraries has enabled screening of the effects of edits on antibiotic resistance (21) and essential gene functions (24,40).…”

“…Additionally, creation of large mutant libraries has enabled screening of the effects of edits on antibiotic resistance (21) and essential gene functions (24,40). While the introduction of desired edits is typically confirmed by Sanger sequencing, the genomes of edited strains are often not sequenced (1,3,32,(35)(36)(37)(38)(39). Thus, the possibility that edited cells might harbor unintended mutations elsewhere in the genome is often overlooked.…”