RNase R Affects the Level of Fatty Acid Biosynthesis Transcripts Leading to Changes in membrane Fluidity
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PROVIDER: PRJNA1090914 | ENA |
REPOSITORIES: ENA
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Project description:Previous studies on RNase R have highlighted significant effects of this ribonuclease in several processes of Streptococcus pneumoniae biology. In this work we show that elimination of RNase R results in overexpression of most of genes encoding the components of type II fatty acid biosynthesis (FASII) cluster. We demonstrate that RNase R is implicated in the turnover of most of transcripts from this pathway, affecting the outcome of the whole FASII cluster, and ultimately leading to changes in the membrane fatty acid composition. Our results show that the membrane of the deleted strain contains higher proportion of unsaturated and long-chained fatty acids than the membrane of the wild type strain. These alterations render the RNase R mutant more prone to membrane lipid peroxidation and are likely the reason for the increased sensitivity of this strain to detergent lysis and to the action of the bacteriocin nisin. Reprogramming of membrane fluidity is an adaptative cell response crucial for bacterial survival in constantly changing environmental conditions. The data presented here is suggestive of a role for RNase R in the composition of S. pneumoniae membrane , with strong impact on pneumococci adaptation to different stress situations.
2024-07-24 | GSE262258 | GEO
Project description:The aim of this work is to investigate whether A. thaliana senses low temperature by perceiving changes in membrane fluidity. To this end, we have performed an experiment to test whether mutant or transgenic plants with altered membrane lipid composition, regulate their gene expression in the same manner as wild type plants in response to cold. Previous work has demonstrated that a change in the expression levels of a number of genes is important in acquiring tolerance to low temperatures. Chemicals which rigidify cell membranes in such a way as to mimic the effects of cold have been shown to be able to induce the expression of such genes. However, because of the non-specific nature of such chemical treatments, it has not been possible to demonstrate unequivocally that the changes in gene expression observed were the result of changes in membrane fluidity. All of the mutants used in our experiment, fab1, fad2-2 and the fad3/fad7/fad8 mutant, have increased lipid saturation levels compared to wild type plants and are thought to have reduced membrane fluidity. The fab1 mutant is also known to be sensitive to chilling. In the fab1 mutant the elongation of 16:0 fatty acids to 18:0 is reduced. The fad2-2 mutant has reduced 18:1 desaturase activity and hence reduced amounts of polyunsaturated phospholipids. The fad3/fad7/fad8 triple mutant is deficient in 18:2 desaturase activity and consequently unable to synthesise trienoic fatty acids. The transgenic line used contained a 35S::FAD3 transgene and in contrast to the mutants tested, should have increased lipid desaturation and increased membrane fluidity. A. thaliana ecotype Col-0 was used as the wild type control for the fab1 and fad2-2 mutants, in addition to the 35S::FAD3 line. The fad3/fad7/fad8 mutant had previously been transformed with the 35S::apoaequorin transgene and a Columbia line expressing apoaequorin under the control of the same promoter, was included to control for the presence of aequorin. Nine day old seedlings grown in petri-dishes on MS were transferred from their growth room (20 oC, 16 h photoperiod, 100 E m-2 s-1) to a growth cabinet (20 oC, 16 h photoperiod,160 m-2 s-1) 24 hours before the experiment began. The next day, one petri-dish of seedlings from each line of plants used was transferred to a cabinet running at 5 oC (16 h photoperiod,160 E m-2 s-1). Control plates remained at 20 oC. Seedlings were harvested after three hours and frozen in liquid nitrogen. 12 samples were used in this experiment
2013-08-30 | E-GEOD-50435 | biostudies-arrayexpress
Project description:The aim of this work is to investigate whether A. thaliana senses low temperature by perceiving changes in membrane fluidity. To this end, we have performed an experiment to test whether mutant or transgenic plants with altered membrane lipid composition, regulate their gene expression in the same manner as wild type plants in response to cold. Previous work has demonstrated that a change in the expression levels of a number of genes is important in acquiring tolerance to low temperatures. Chemicals which rigidify cell membranes in such a way as to mimic the effects of cold have been shown to be able to induce the expression of such genes. However, because of the non-specific nature of such chemical treatments, it has not been possible to demonstrate unequivocally that the changes in gene expression observed were the result of changes in membrane fluidity. All of the mutants used in our experiment, fab1, fad2-2 and the fad3/fad7/fad8 mutant, have increased lipid saturation levels compared to wild type plants and are thought to have reduced membrane fluidity. The fab1 mutant is also known to be sensitive to chilling. In the fab1 mutant the elongation of 16:0 fatty acids to 18:0 is reduced. The fad2-2 mutant has reduced 18:1 desaturase activity and hence reduced amounts of polyunsaturated phospholipids. The fad3/fad7/fad8 triple mutant is deficient in 18:2 desaturase activity and consequently unable to synthesise trienoic fatty acids. The transgenic line used contained a 35S::FAD3 transgene and in contrast to the mutants tested, should have increased lipid desaturation and increased membrane fluidity. A. thaliana ecotype Col-0 was used as the wild type control for the fab1 and fad2-2 mutants, in addition to the 35S::FAD3 line. The fad3/fad7/fad8 mutant had previously been transformed with the 35S::apoaequorin transgene and a Columbia line expressing apoaequorin under the control of the same promoter, was included to control for the presence of aequorin. Nine day old seedlings grown in petri-dishes on MS were transferred from their growth room (20 oC, 16 h photoperiod, 100 E m-2 s-1) to a growth cabinet (20 oC, 16 h photoperiod,160 m-2 s-1) 24 hours before the experiment began. The next day, one petri-dish of seedlings from each line of plants used was transferred to a cabinet running at 5 oC (16 h photoperiod,160 E m-2 s-1). Control plates remained at 20 oC. Seedlings were harvested after three hours and frozen in liquid nitrogen.
2013-08-30 | GSE50435 | GEO
Project description:The aim of this work is to investigate whether A. thaliana senses low temperature by perceiving changes in membrane fluidity. To this end, we have performed an experiment to test whether mutant or transgenic plants with altered membrane lipid composition, regulate their gene expression in the same manner as wild type plants in response to cold. Previous work has demonstrated that a change in the expression levels of a number of genes is important in acquiring tolerance to low temperatures. Chemicals which rigidify cell membranes in such a way as to mimic the effects of cold have been shown to be able to induce the expression of such genes. However, because of the non-specific nature of such chemical treatments, it has not been possible to demonstrate unequivocally that the changes in gene expression observed were the result of changes in membrane fluidity. All of the mutants used in our experiment, fab1, fad2-2 and the fad3/fad7/fad8 mutant, have increased lipid saturation levels compared to wild type plants and are thought to have reduced membrane fluidity. The fab1 mutant is also known to be sensitive to chilling. In the fab1 mutant the elongation of 16:0 fatty acids to 18:0 is reduced. The fad2-2 mutant has reduced 18:1 desaturase activity and hence reduced amounts of polyunsaturated phospholipids. The fad3/fad7/fad8 triple mutant is deficient in 18:2 desaturase activity and consequently unable to synthesise trienoic fatty acids. The transgenic line used contained a 35S::FAD3 transgene and in contrast to the mutants tested, should have increased lipid desaturation and increased membrane fluidity. A. thaliana ecotype Col-0 was used as the wild type control for the fab1 and fad2-2 mutants, in addition to the 35S::FAD3 line. The fad3/fad7/fad8 mutant had previously been transformed with the 35S::apoaequorin transgene and a Columbia line expressing apoaequorin under the control of the same promoter, was included to control for the presence of aequorin. Nine day old seedlings grown in petri-dishes on MS were transferred from their growth room (20 oC, 16 h photoperiod, 100 E m-2 s-1) to a growth cabinet (20 oC, 16 h photoperiod,160 m-2 s-1) 24 hours before the experiment began. The next day, one petri-dish of seedlings from each line of plants used was transferred to a cabinet running at 5 oC (16 h photoperiod,160 E m-2 s-1). Control plates remained at 20 oC. Seedlings were harvested after three hours and frozen in liquid nitrogen.
2008-02-15 | E-NASC-66 | biostudies-arrayexpress
Project description:Two types of RNA:DNA associations can lead to genome instability: the formation of R-loops during transcription and the incorporation of ribonucleotide monophosphates (rNMPs) into DNA during replication. Both ribonuclease (RNase) H1 and RNase H2 degrade the RNA component of R-loops, whereas only RNase H2 can remove one or a few rNMPs from DNA. We performed high-resolution mapping of mitotic recombination events throughout the yeast genome in diploid strains of Saccharomyces cerevisiae lacking RNase H1 (rnh1Δ), RNase H2 (rnh201Δ), or both RNase H1 and RNase H2 (rnh1Δ rnh201Δ). We found little effect on recombination in the rnh1Δ strain, but elevated recombination in both the rnh201Δ and the double-mutant strains; levels of recombination in the double mutant were about 50% higher than in the rnh201 single-mutant strain. An rnh201Δ mutant that additionally contained a mutation that reduces rNMP incorporation by DNA polymerase ε (pol2-M644L) had a level of instability similar to that observed in the presence of wild-type Polε. This result suggests that the elevated recombination observed in the absence of only RNase H2 is primarily a consequence of R loops rather than misincorporated rNMPs.
2015-09-23 | GSE73334 | GEO
Project description:RNase L is a regulated endoribonuclease in higher vertebrates that functions in antiviral innate immunity. Interferons induce OAS enzymes that sense double-stranded RNA of viral origin leading to synthesis of 2’,5’-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L modulates host transcriptome through its endoribonuclease activity. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A was directly introduced into cells. Here we report that RNase L activation by 2-5A causes a ribotoxic stress response that requires the ribosome-associated MAP3K, ZAK. Subsequently, the stress-activated protein kinases (SAPK) JNK and p38 are phosphorylated. RNase L activation profoundly altered the transcriptome by widespread depletion of mRNAs associated with different cellular functions, but also by SAPK-dependent induction of inflammatory genes. Our findings show that 2-5A is a ribotoxic stressor that causes RNA damage through RNase L triggering a ZAK kinase cascade leading to proinflammatory signaling and apoptosis.
2024-03-01 | GSE253530 | GEO
Project description:Cytoplasmic double-stranded RNA is sensed by RIG-I-like receptors (RLR) leading to induction of type-I interferons (IFN-I), proinflammatory cytokines and apoptosis in tumor cells. Here, we elucidate the differential signaling mechanisms leading to cytokine secretion and/or cell death induction upon stimulation with the bona fide RIG-I ligand 5’-triphosphate RNA (3p-RNA). We show that both outcomes are mediated by distinct dsRNA-receptor families with RLR being essential for cytokine production and IFN-mediating priming of effector pathways, but not apoptosis itself. Affinity purification followed by mass spectrometry revealed 3p-RNA-specific binding and activation of oligoadenylate synthetase 1/RNase L. RNase L-deficient cells were profoundly impaired in their ability to undergo apoptosis. Mechanistically, the concerted action of translational arrest triggered by RNase L and upregulation of NOXA was needed to deplete anti-apoptotic MCL-1 causing intrinsic apoptosis. Thus, 3p-RNA-induced apoptosis is a two-step process consisting of a RIG-I-dependent priming and a RNase L-dependent effector phase.
2021-05-12 | GSE150658 | GEO
Project description:The Escherichia coli endoribonucleases RNase E (Rne) and RNase G (Rng) have sequence similarity and broadly similar sequence specificity. Whereas the absence of Rne normally is lethal, we show here that E. coli bacteria that lack the rne gene can be made viable by overexpression of Rng. Rng-complemented cells accumulated precursors of 5S ribosomal RNA (rRNA) and the RNA component of RNase P (i.e. M1 RNA), indicating that normal processing of these Rne-cleaved RNAs was not restored by RNase G; additionally, neither 5S rRNA nor M1 RNA was generated from precursors by RNase G cleavage in vitro. Using DNA microarrays containing 4405 Escherichia coli open reading frames (ORFs), we identified mRNAs whose steady-state level was affected by Rne, Rng or the N-terminal catalytic domain of RNase E. Most transcript species affected by RNase E deficiency were also elevated in an rne deletion mutant complemented by Rng. However, approximately 100 mRNAs that accumulated in Rne-deficient cells were decreased by rng-complemention, thus identifying targets whose processing or degradation may be the basis for RNase E essentiality. Remarkably prominent in this group were mRNAs implicated in energy-generating pathways or in the synthesis or degradation of macromolecules. Set of arrays that are part of repeated experiments Keywords: Biological Replicate
2005-08-13 | GSE3123 | GEO
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:It is known the deleterious effects of diabetes on embryos, but the effects of diabetes on placenta and its mitochondria are still not well known. In this work we generated a mild hyperglycemia model in female wistar rats by intraperitoneal injection of streptozotocin in 48 hours-old rats. The sexual maturity onset of the female rats was delayed around 6-7 weeks and at 16 weeks-old they were mated, and sacrificed at day 19th of pregnancy. In placental total tissue and isolated mitochondria, the fatty acids composition was analyzed by gas chromatography, and lipoperoxidation was measured by thiobarbituric acid reactive substances. Membrane fluidity in mitochondria was measured with the excimer forming probe dipyrenylpropane and mitochondrial function was measured with a Clark-type electrode. The results show that even a chronic mild hyperglycemia increases lipoperoxidation and decreases mitochondrial function in placenta. Simultaneously, placental fatty acids metabolism in total tissue is modified but in a different way than in placental mitochondria. Whereas the chronic mild hyperglycemia induced a decrease in unsaturated to saturated fatty acids ratio (U/S) in placental total tissue, the ratio increased in placental mitochondria. The measurements of membrane fluidity showed that fluidity of placenta mitochondrial membranes increased with hyperglycemia, showing consistency with the fatty acids composition through the U/S index. The thermotropic characteristics of mitochondrial membranes were changed, showing lower transition temperature and activation energies. All of these data together demonstrate that even a chronic mild hyperglycemia during pregnancy of early reproductive Wistar rats, generates an increment of lipoperoxidation, an increase of placental mitochondrial membrane fluidity apparently derived from changes in fatty acids composition and consequently, mitochondrial malfunction.
| S-EPMC4667935 | biostudies-literature