A remarkable feature of many small non-coding RNAs (sRNAs) Escherichia coli and Salmonella is their accumulation in the stationary phase bacterial growth. Several stress response regulators sigma factors have been reported to direct transcription phase-specific sRNAs, but a widely conserved sRNA gene that controlled by major factor, σ S (RpoS), has remained elusive. We studied SdsR sRNA, previously known as RyeB, one most abundant sRNAs E. coli. Alignments sdsR promoter region genetic...

Bacterial small RNAs (sRNAs) are key elements of regulatory networks that modulate gene expression. The sRNA RydC Salmonella sp. and Escherichia coli is an example this class riboregulators. Like many other sRNAs, bears a ‘seed’ region recognises specific transcripts through base-pairing, its activities facilitated by the RNA chaperone Hfq. crystal structure in complex with E. Hfq at 3.48 Å resolution illuminates how protein interacts presents for target recognition. Consolidating...

The ubiquitous RNA chaperone Hfq is involved in the regulation of key biological processes many species across bacterial kingdom. In opportunistic human pathogen Klebsiella pneumoniae , deletion hfq gene affects global transcriptome, virulence, and stress resistance; however, ligands major RNA-binding protein this have remained elusive. study, we combined transcriptomic, co-immunoprecipitation, interactome analyses to compile an inventory conserved species-specific RNAs bound by monitor...

Bacteria use quorum sensing to monitor cell density and coordinate group behaviours. In Vibrio cholerae, the causative agent of diarrheal disease cholera, is connected virulence gene expression via two autoinducer molecules, AI-2 CAI-1. Both autoinducers share one signal transduction pathway control production AphA, a key transcriptional activator biofilm formation genes. this study, we demonstrate that recently identified autoinducer, DPO, also controls AphA in V. cholerae. functioning...

Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most which are yet unknown. Some sRNAs remarkably well conserved, indicating that they serve cellular functions go beyond the necessities a single species. One these 'core sRNAs' largely unknown function is abundant ∼100-nucleotide SdsR sRNA transcribed by general stress σ-factor, σS accumulates in stationary phase. In Salmonella, was known to inhibit...

In the pathogen Pseudomonas aeruginosa, LasR is a quorum sensing (QS) master regulator that senses concentration of secreted autoinducers as proxy for bacterial cell density. Counterintuitively, previous studies showed saturating amounts ligand, 3OC12-HSL, fail to induce full regulon in low-density liquid cultures. Here we demonstrate surface association, which necessary many same group behaviors QS, promotes stronger QS responses. We show lasR upregulated upon and surface-associated...

The human malaria parasite Plasmodium falciparum exports determinants of virulence and pathology to destinations within the host erythrocyte, including erythrocyte cytoplasm, plasma membrane profiles origin termed Maurer’s clefts. Most exported proteins contain a conserved pentameric motif plasmodial export element (PEXEL)/vacuolar transfer signal (VTS) that functions as cleavable sorting permitting erythrocyte. However, there are some proteins, such skeleton‐binding protein 1 (PfSBP1) lack...

Altering membrane protein and lipid composition is an important strategy for maintaining integrity during environmental stress. Many bacterial small RNAs (sRNAs) control production, but sRNA-mediated regulation of fatty acid less well understood. The sRNA RydC was previously shown to stabilize cfa (cyclopropane synthase) mRNA, resulting in higher levels cyclopropane acids the cell membrane. Here, we report that additional sRNAs, ArrS CpxQ, also directly regulate posttranscriptionally. act...

<title>Abstract</title> In bacteria, regulatory networks controlling the adaptation of gene expression in response to stress are frequently complemented by base-pairing small RNAs (sRNAs) that act at post-transcriptional level. While many circuits governing resilience have been studied model bacterium Caulobacter crescentus, only a fraction its diverse sRNA repertoire has characterized. this study, we globally identified interacting RNA-RNA pairs associated with major RNA-binding protein Hfq...

Hfq (host factor for phage Q beta) is key posttranscriptional gene regulation in many bacteria. Hfq’s function to stabilize sRNAs and facilitate base-pairing with trans -encoded target mRNAs. Loss of typically results pleiotropic phenotypes, and, the major human pathogen Vibrio cholerae , inactivation has been linked reduced virulence, failure produce biofilms, impaired intercellular communication. However, RNA ligands V. are currently unknown. Here, we used RIP-seq (RNA immunoprecipitation...

Abstract Vibrio cholerae , the cause of cholera disease, exhibits a characteristic curved rod morphology, which promotes infectivity and motility in dense hydrogels. Periplasmic protein CrvA determines cell curvature V. yet regulatory factors controlling are unknown. Here, we discover VadR small RNA (sRNA) as post-transcriptional inhibitor crvA mRNA. Mutation vadR increases curvature, whereas overexpression has inverse effect. We show that transcription is activated by VxrAB two-component...

ABSTRACT The alphaproteobacterium Caulobacter crescentus thrives in oligotrophic environments and is able to optimally exploit minimal resources by entertaining an intricate network of gene expression control mechanisms. Numerous transcriptional activators repressors have been reported contribute these processes, but only few studies focused on regulation at the post-transcriptional level C. . Small RNAs (sRNAs) are a prominent class regulators bacterial expression, most sRNAs characterized...

Abstract The ompD transcript, encoding an outer membrane porin in Salmonella, harbors a controlling element its coding region that base-pairs imperfectly with ‘seed’ of the small regulatory RNA (sRNA) MicC. When tagged sRNA, mRNA is cleaved downstream pairing site by conserved endoribonuclease RNase E, leading to transcript destruction. We observe sRNA-induced cleavage accessible E vitro upon recruitment into 30S translation pre-initiation complex (PIC) presence degradosome components....

Bacterial small RNAs (sRNAs) are a heterogeneous group of post-transcriptional regulators that often act at the heart large networks. Hundreds sRNAs have been discovered by genome-wide screens and most these exert their functions base-pairing with target mRNAs. However, studies addressing molecular roles largely confined to gamma-proteobacteria, such as Escherichia coli. Here we identify characterize novel sRNA, ChvR, from alpha-proteobacterium Caulobacter crescentus. Transcription chvR is...

We have solved the X-ray crystal structure of RNA chaperone protein Hfq from alpha-proteobacterium Caulobacter crescentus to 2.15-Å resolution, resolving conserved core and entire C-terminal domain (CTD). The reveals that CTD neighboring hexamers pack in contacts, acidic residues at tip interact with positive on rim Hfq, as has been recently proposed for a mechanism modulating binding. De novo computational models predict similar docking against Hfq. also show C. sRNA binding annealing...

The small GTPase ADP‐ribosylation factor‐1 (Arf1) plays a key role in the formation of coat protein I (COP I)‐coated vesicles. Upon recruitment to donor Golgi membrane by interaction with dimeric p24 proteins, Arf1’s GDP is exchanged for GTP. Arf1‐GTP then dissociates from p24, and together other it recruits coatomer, heptameric complex COP vesicles, cytosol. In this process, Arf1 was shown specifically interact coatomer β γ‐COP subunits through its switch region, ɛ‐COP. Here, we mapped...

P-bodies are dynamic aggregates of RNA and proteins involved in several post-transcriptional regulation processes. have been shown to play important roles regulating viral infection, whereas their interplay with bacterial pathogens, specifically intracellular bacteria that extensively manipulate host cell pathways, remains unknown. Here, we report Salmonella infection induces P-body disassembly a type-specific manner, independently previously characterized pathways such as inhibition...

Regulation at the post-transcriptional level is an important mode of gene expression control in bacteria. Small RNA regulators (sRNAs) that act via intramolecular base-pairing with target mRNAs are key players this process and most often sequester target's ribosome binding site (RBS) to down-regulate translation initiation. Over past few years, several exceptions from mechanism have been reported, revealing sRNAs able influence initiation a distance. In issue Molecular Microbiology, Azam...