Defining the role of RNase E in the mycobacterial degradosome-like network
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ABSTRACT:
ORGANISM(S): Mycolicibacterium smegmatis
PROVIDER: GSE313996 | GEO | 2025/12/31
REPOSITORIES: GEO
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Project description:RNA degradation is an essential process that allows bacteria to regulate gene expression and has emerged as an important mechanism for controlling virulence. However, the individual contributions of RNases in this process are mostly unknown. Here, we report that of 11 tested potential RNases of the intestinal pathogen Yersinia pseudotuberculosis, two, the endoribonuclease RNase III and the exoribonuclease PNPase, repress the synthesis of the master virulence regulator LcrF. LcrF activates the expression of virulence plasmid genes encoding the type III secretion system (Ysc-T3SS) and its substrates (Yop proteins), that are employed to inhibit immune cell functions during infection. Loss of both RNases led to an increase in lcrF mRNA levels and stability. Our work indicates that PNPase exerts its influence through YopD, known to accelerate lcrF mRNA degradation. Loss of RNase III results in the downregulation of the CsrB and CsrC RNAs, leading to increased availability of active CsrA, which has previously been shown to enhance lcrF mRNA translation and stability. Other factors that influence the translation process and were found to be differentially expressed in the RNase III-deficient mutant could support this process. Transcriptomic profiling further revealed that Ysc-T3SS-mediated Yop secretion leads to global reprogramming of the Yersinia transcriptome with a massive shift of the expression from chromosomal towards virulence plasmid-encoded genes. A similar extensive transcriptional reprogramming was also observed in the RNase III-deficient mutant under non-secretion conditions. This illustrated that RNase III enables immediate coordination of virulence traits, such as Ysc-T3SS/Yops, with other functions required for host-pathogen interactions and survival in the host.
2024-01-23 | GSE249386 | GEO
Project description:RNA helicases—central enzymes in RNA metabolism— often feature intrinsically disordered regions (IDRs) that enable phase separation and complex interactions with other proteins and/or RNA molecules. IDRs are varied and fast evolving, which makes their function hard to predict. In the bacterial pathogen Pseudomonas aeruginosa, two non-redundant RNA helicases, RhlE1 and RhlE2, share a conserved REC catalytic core but have different C-terminal extensions (CTEs) composed of IDRs of diverse length and amino acid composition. Here, we show how the IDR diversity defines RhlE RNA helicase specificity of function. Both CTEs facilitate RNA binding and phase separation in vitro, leading to the in vivo localization of proteins in clusters within the cytoplasm. However, the CTE of RhlE2 is more efficient in enhancing REC core RNA unwinding, exhibits a greater tendency for phase separation, and interacts with the RNase E endonuclease, a crucial player in mRNA degradation. Swapping CTEs results in chimeric proteins that are biochemically active but functionally distinct as compared to their native counterparts. The RECRhlE1-CTERhlE2 chimera improves cold growth of a rhlE1 mutant, gains interaction with RNase E and affects a subset of both RhlE1 and RhlE2 RNA targets. The RECRhlE2-CTERhlE1 chimera instead hampers bacterial growth at low temperatures in the absence of RhlE1, with its detrimental effect linked to aberrant RNA droplets. By showing that IDRs modulate both protein core activities and subcellular localization, our study defines the impact of IDR diversity on the functional differentiation of RNA helicases.
2024-05-30 | GSE253333 | GEO
Project description:UV-crosslining of protein-RNA complexes was employed to capture sRNA-mRNA interactions occuring on the RNA degradosome protein, RNase E, in enterohaemorhaggic E. coli. Abstract from associated mansucript: In many organisms small regulatory RNAs (sRNA) play important roles in the regulation of gene expression by base-pairing to specific target mRNAs. In enterohaemorrhagic E. coli (EHEC), sRNAs are encoded by both the “core” genome and in numerous horizontally acquired pathogenicity islands. To identify functionally important sRNA-target RNA interactions we applied crosslinking and sequencing of hybrids (CLASH) to the core degradosome component RNase E in EHEC. RNase E was shown to bind to many classes of RNA, confirming the wide distribution of degradosome targets. These included several hundred sRNA-mRNA duplexes, and the distribution of non-templated oligo(A) tails indicated that the sRNA target RNase E-mediated cleavage at these interaction sites. Functional repression of target mRNAs was confirmed for the core sRNA RyhB, and the pathogenicity-associated sRNA Esr41. In the case of Esr41, three confirmed target mRNAs participate in iron accumulation and the ∆esr41 strain showed increased growth under conditions of iron limitation. We conclude that CLASH can be used to identify functional targets for bacterial sRNAs.
2017-02-14 | GSE77463 | GEO
Project description:RNase E, an essential endoribonuclease in Escherichia coli, is the key component of the multienzyme RNA degradosome, which is localized to the inner cytoplasmic membrane. Until now, the reason for membrane localization of RNase E was not known. We have analyzed ribosome assembly in the rneΔMTS strain, which expresses a cytoplasmic variant of RNase E (cRNase E) resulting in a cytoplasmic RNA degradosome. In this mutant strain, there is a mild slowdown in the rates of growth and mRNA degradation. Here we document the striking accumulation of intermediates in ribosome assembly in the rneΔMTS strain in which precursors of 16S and 23S rRNA are cleaved by cRNase E. In vitro, we show that ribosomes partially unfolded in low ionic strength buffer are cleaved by RNase E. Mapping of in vivo and in vitro cleavage sites shows that they overlap and that their consensus sequence matches previously mapped RNase E cleavage sites. In vivo, fragments of 16S and 23S rRNA as well as a precursor of 5S rRNA are degraded in a pathway involving polyadenylation and 3’ exonucleases. Since the pathway for rRNA degradation is the same as the pathway for mRNA degradation, the slowdown of mRNA degradation in the rneΔMTS strain could be due to competition by rRNA degradation. Our results strongly suggest that the RNA degradosome participates in the quality control of ribosome assembly and that localization on the inner cytoplasmic membrane protects newly synthesized intermediates from wasteful degradation. Ribosome synthesis is costly. Since growth rate correlates with ribosome synthesis rate, slow growth rate of the rneΔMTS strain is due to the degradation of a proportion of newly synthesized ribosomes. Avoiding wasteful degradation of intermediates in ribosome assembly likely explains why localization of RNase E homologues to the inner cytoplasmic membrane is conserved throughout the γ-Proteobacteria.
2023-01-16 | PXD038317 | Pride
Project description:Bacterial adaptation to stress involves changes in transcription and mRNA degradation rates. In Escherichia coli, the Nudix hydrolase RppH initiates mRNA degradation by removing pyrophosphate from mRNA 5’-ends, converting 5’-triphosphates to 5’-monophosphates. We aimed to identify the RppH homolog in the globally important pathogen Mycobacterium tuberculosis (Mtb). We deleted each non-essential Nudix gene from Mtb to determine their impacts on mRNA 5’-phosphorylation. Deletion of mutT4 (Rv3908) increased the relative abundance of 5’-triphosphates on myriad mRNAs across the transcriptome. Purified MutT4 converted mRNA 5’-triphosphates into monophosphates, and stimulated degradation by RNase E and RNase J. MutT4 has intrinsically disordered regions (IDRs), a common domain for biomolecular condensate formation. Microscopy showed that MutT4 forms condensates that dissociate upon addition of rifampicin, and that the N-terminal IDR is sufficient for condensate formation. These MutT4 condensates localize with RNase E and RNase J. Deletion of mutT4 in Mtb leads to a higher outer membrane permeability and resistance to oxidative stress. We conclude that MutT4 is the RppH of Mtb, assembling in condensates that may act as degradation hubs. Our data indicate that MutT4 is unlikely to participate in DNA repair or nucleotide pool cleansing, and as such would more accurately be called RppH.
2025-03-26 | GSE292713 | GEO
Project description:Abstract: RNase E, an essential endoribonuclease of Escherichia coli, interacts through its C-terminal region with multiple other proteins to form a complex termed the RNA degradosome. To investigate the degradosome's proposed role as an RNA decay machine, we used DNA microarrays to globally assess alterations in the steady-state abundance and decay of 4,289 E. coli mRNAs at single-gene resolution in bacteria carrying mutations in the degradosome constituents RNase E, polynucleotide phosphorylase, RhlB helicase, and enolase. Our results show that the functions of all four of these proteins are necessary for normal mRNA turnover. We identified specific transcripts and functionally distinguishable transcript classes whose half-life and abundance were affected congruently by multiple degradosome proteins, affected differentially by mutations in degradosome constituents, or not detectably altered by degradosome mutations. Our results, which argue that decay of some E. coli mRNAs in vivo depends on the action of assembled degradosomes, whereas others are acted on by degradosome proteins functioning independently of the complex, imply the existence of structural features or biochemical factors that target specific classes of mRNAs for decay by degradosomes This SuperSeries is composed of the SubSeries listed below.
2006-03-08 | GSE4394 | GEO
Project description:Autophagy targets a wide variety of substrates for degradation within lysosomes. Although lysosomes are known to possess RNase activity, the role of lysosomal RNA degradation in post-transcriptional gene regulation is not well understood. We defined RNASET2, PLD3, and both endogenous and exogenous RNase A family members as lysosomal RNases. Cells lacking these RNases accumulated large amounts of lysosomal RNA. Quantitative RNA sequencing of lysosomal contents revealed that although all RNA types can enter lysosomes, the SRP RNAs, Y RNAs, 5′ TOP mRNAs, long-lived mRNAs, and mRNAs encoding membrane and secreted proteins were specifically enriched. This specificity was due to autophagy, and lysosomally degraded transcripts had autophagy-dependent changes in stability. To explore the basis of this specificity, we identified sequence motifs of SRP RNAs and 5′ TOP mRNAs that are necessary and sufficient for enhanced lysosomal targeting. Our results establish lysosomes as selective modulators of cellular RNA content.
2025-12-08 | GSE296736 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE3977: Comparative Transcript Abundance in E. Coli Degradosome Mutants and their Parental Strains GSE3978: mRNA Decay in E. Coli Degradosome Mutants and their Parental Strains Abstract: RNase E, an essential endoribonuclease of Escherichia coli, interacts through its C-terminal region with multiple other proteins to form a complex termed the RNA degradosome. To investigate the degradosome's proposed role as an RNA decay machine, we used DNA microarrays to globally assess alterations in the steady-state abundance and decay of 4,289 E. coli mRNAs at single-gene resolution in bacteria carrying mutations in the degradosome constituents RNase E, polynucleotide phosphorylase, RhlB helicase, and enolase. Our results show that the functions of all four of these proteins are necessary for normal mRNA turnover. We identified specific transcripts and functionally distinguishable transcript classes whose half-life and abundance were affected congruently by multiple degradosome proteins, affected differentially by mutations in degradosome constituents, or not detectably altered by degradosome mutations. Our results, which argue that decay of some E. coli mRNAs in vivo depends on the action of assembled degradosomes, whereas others are acted on by degradosome proteins functioning independently of the complex, imply the existence of structural features or biochemical factors that target specific classes of mRNAs for decay by degradosomes Refer to individual Series
2006-03-07 | E-GEOD-4394 | biostudies-arrayexpress
Project description:mRNA decay in E. Coli degradosome mutants and their parental strains following transcriptional arrest with rifampicin. Abstract: RNase E, an essential endoribonuclease of Escherichia coli, interacts through its C-terminal region with multiple other proteins to form a complex termed the RNA degradosome. To investigate the degradosome's proposed role as an RNA decay machine, we used DNA microarrays to globally assess alterations in the steady-state abundance and decay of 4,289 E. coli mRNAs at single-gene resolution in bacteria carrying mutations in the degradosome constituents RNase E, polynucleotide phosphorylase, RhlB helicase, and enolase. Our results show that the functions of all four of these proteins are necessary for normal mRNA turnover. We identified specific transcripts and functionally distinguishable transcript classes whose half-life and abundance were affected congruently by multiple degradosome proteins, affected differentially by mutations in degradosome constituents, or not detectably altered by degradosome mutations. Our results, which argue that decay of some E. coli mRNAs in vivo depends on the action of assembled degradosomes, whereas others are acted on by degradosome proteins functioning independently of the complex, imply the existence of structural features or biochemical factors that target specific classes of mRNAs for decay by degradosomes. An RNA stablity experiment design type examines stability and/or decay of RNA transcripts. Keywords: RNA_stability_design
2006-01-06 | GSE3978 | GEO
Project description:RNases perform indispensable functions in regulating gene expression in many bacterial pathogens by processing and/or degrading RNAs. Despite the pivotal role of RNases in regulating bacterial virulence factors, the functions of RNases have not yet been studied in the major human respiratory pathogen Streptococcus pneumoniae (pneumococcus). Here, we sought to determine the impact of two conserved RNases, the endoribonuclease RNase Y and exoribonuclease polynucleotide phosphorylase (PNPase), on the physiology and virulence of S. pneumoniae serotype 2 strain D39. We report that RNase Y and PNPase are essential for pneumococcal pathogenesis as both deletion mutants showed strong attenuation of virulence in murine models of invasive pneumonia. Genome-wide transcriptomic analysis revealed that nearly 200 mRNA transcripts were significantly up-regulated, whereas the abundance of several pneumococcal sRNAs, including the Ccn (CiaR Controlled Noncoding RNA) sRNAs, were altered in the ∆rny mutant relative to the wild-type strain. Additionally, lack of RNase Y resulted in pleiotropic phenotypes that included defects in pneumococcal cell morphology and growth in vitro. In contrast, Dpnp mutants showed no growth defect in vitro, but differentially expressed a total of 40 transcripts including the tryptophan biosynthesis operon genes and numerous 5’-cis-acting regulatory RNAs, a majority of which were previously shown to impact pneumococcal disease progression in mice using the serotype 4 strain TIGR4. Altogether our data suggest that RNase Y exerts a global impact on pneumococcal physiology, while PNPase-mediates virulence phenotypes, likely through sRNA regulation.
2021-09-02 | GSE173392 | GEO