A dual T-box riboswitch in Enterococcus faecium binds two tRNAs
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ABSTRACT:
PROVIDER: PRJNA678524 | ENA |
REPOSITORIES: ENA
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Project description:A set of small RNAs was identified in Vancomycin-resistant Enterococcus faecium, a leading cause of MDR infections. We described here the function of srn_2050, acting as a T-box riboswitch to regulate expression of downstream genes encoding the HisRS and AspRS aminoacyl-tRNA synthetases. Comparative RNAseq between Aus0004 and isogenic srn_2050 mutant identified the genes whose expression is impacted by the RNA. srn_2050 structure in its ‘off state’ was deciphered by in-line probing, containing T-box consensus sequences, a pseudoknot, a specifier loop and a terminator. Transcription binding assays between the riboswitch and either tRNAAsp or tRNAHis indicate that each deacylated tRNA interacts with the T-box. Their anticodons bind to a GACAC sequence within the specifier loop (GAC and CAC are Asp and His codons, respectively), whereas tRNATyr (UA/C-U) does not. A pioneering evaluation of E. faecium amino acid auxotrophy, with emphasis on E. faecium strain Aus0004, revealed auxotrophy for Histidine but not for Aspartic acid. Based on comparative growths and RNAseq between Aus004 and Aus004-srn2050, the riboswitch is shown essential for growth under aspartate starvation. This is the first example of a functional riboswitch in E. faecium with two overlapping codons allowing a dual tRNA-dependent regulation at transcriptional level.
2020-11-16 | GSE161499 | GEO
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Project description:In Staphylococcus aureus, de novo methionine biosynthesis is regulated by a unique hierarchical pathway involving stringent-response controlled CodY repression in combination with a T-box riboswitch and RNA decay. The T-box riboswitch residing in the 5' untranslated region (met leader RNA) of the S. aureus metICFE-mdh operon controls downstream gene transcription upon interaction with uncharged methionyl-tRNA. met leader and metICFE-mdh (m)RNAs undergo RNase-mediated degradation in a process whose molecular details are poorly understood. Here, we determined the secondary structure of the met leader RNA and found the element to harbor, beyond other conserved T-box riboswitch structural features, a terminator helix which is a target for RNase III endoribonucleolytic cleavage. As the terminator is a thermodynamically highly stable structure, it also forms posttranscriptionally in met leader/ metICFE-mdh read-through transcripts. Cleavage by RNase III releases the met leader from metICFE-mdh mRNA and initiates RNase J-mediated degradation of the mRNA from the 5'-end. Of note, metICFE-mdh mRNA stability varies over the length of the transcript with a longer lifespan towards the 3'-end. Corresponding variations in protein levels led us to hypothesize that coordinated RNA decay represents another level in the hierarchical methionine biosynthesis control network to adjust methionine biosynthesis enzyme amounts to current metabolic requirements.
2021-08-10 | PXD020619 | Pride
Project description:In Staphylococcus aureus, de novo methionine biosynthesis is regulated by a unique hierarchical pathway involving stringent-response controlled CodY repression in combination with a T-box riboswitch and RNA decay. The T-box riboswitch residing in the 5' untranslated region (met leader RNA) of the S. aureus metICFE-mdh operon controls downstream gene transcription upon interaction with uncharged methionyl-tRNA. met leader and metICFE-mdh (m)RNAs undergo RNase-mediated degradation in a process whose molecular details are poorly understood. Here, we determined the secondary structure of the met leader RNA and found the element to harbor, beyond other conserved T-box riboswitch structural features, a terminator helix which is a target for RNase III endoribonucleolytic cleavage. As the terminator is a thermodynamically highly stable structure, it also forms posttranscriptionally in met leader/ metICFE-mdh read-through transcripts. Cleavage by RNase III releases the met leader from metICFE-mdh mRNA and initiates RNase J-mediated degradation of the mRNA from the 5'-end. Of note, metICFE-mdh mRNA stability varies over the length of the transcript with a longer lifespan towards the 3'-end. Corresponding variations in protein levels led us to hypothesize that coordinated RNA decay represents another level in the hierarchical methionine biosynthesis control network to adjust methionine biosynthesis enzyme amounts to current metabolic requirements.
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Project description:Plant basic helix-loop-helix (bHLH) transcription factors are involved in physiological and developmental processes, and also play essential roles in abiotic stresses. However, their exact roles in abiotic stress are still need to be elucidated, and most of bHLHs have not been functionally characterized. In the present study, we characterized the functional role of AtbHLH112 in response to abiotic stresses. AtbHLH112 is a nuclear-localized protein, and its nuclear-localization is induced by salt, drought and ABA. Besides binding to E-box motif, AtbHLH112 is found to bind to a novel motif with the sequence M-bM-^@M-^\GG[GT]CC[GT][GA][TA]CM-bM-^@M-^] (GCG-box), and the binding affinity is induced by salt and ABA. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by upregulating the expression of P5CS genes and decreasing the expression of P5CDH and PRODH genes to increase proline levels, and via enhancing the expression of POD and SOD genes to improve ROS scavenging ability. All data together suggested that AtbHLH112 regulates the expression of genes through binding to GCG-box and E-box to mediate the physiological stress responses, including proline biosynthesis and ROS scavenging pathways to enhance stress tolerance. Differentially expression genes of AtbHLH112-overexpression plants, mutant (SALK_033618C) plants and wild type of Columbia Arabidopsis thaliana were measured under salt stressed and normal condition for 3 hours, respectively. Three independent experiments were performed at each treatment using different plants for each experiment.
2014-08-09 | E-GEOD-60260 | biostudies-arrayexpress
Project description:Plant basic helix-loop-helix (bHLH) proteins play essential roles in physiological and developmental processes and are also involved in abiotic stresses. However, their exact roles in abiotic stress are still not fully understood, and most of them have not been functionally characterised. In the present study, we characterised the functional role of AtbHLH112 in response to abiotic stress. A WRKY gene, AtWRKY66, can regulate the expression of the AtbHLH112 via binding to W-box motifs present in its promoter. AtbHLH112 is a nuclear-localised protein, and its nuclear localisation is increased upon exposure to NaCl, mannitol and ABA. In addition to binding to the G-box motif, AtbHLH112 is found to bind to a novel motif M-bM-^@M-^\GGGCCGGTCM-bM-^@M-^] (named the GCG-box) to regulate gene expression. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with tolerance to salt and drought. AtbHLH112 can confer stress tolerance via enhanced expression of POD and SOD genes to improve ROS scavenging ability and via upregulated expression of P5CS genes and decreased expression of P5CDH and PRODH genes to improve proline levels. Our data suggested that AtbHLH112 regulates the expression of genes via binding to the G-box and the GCG-box to improve stress-related pathways, such as ROS scavenging and proline biosynthesis. Differentially expression genes of AtbHLH112-overexpression plants and mutant (SALK_033618C) plants of Arabidopsis thaliana were measured under salt stressed and normal condition for 3 hours, respectively. Three independent experiments were performed at each treatment using different plants for each experiment.
2013-11-14 | E-GEOD-52326 | biostudies-arrayexpress
Project description:The CCA-adding enzyme adds CCA to the 3' ends of transfer RNAs (tRNAs), a critical step in tRNA biogenesis that generates the amino acid attachment site. We found that the CCA-adding enzyme plays a key role in tRNA quality control by selectively marking unstable tRNAs and tRNA-like small RNAs for degradation. Instead of adding CCA to the 3' ends of these transcripts, CCA-adding enzymes from all three kingdoms of life add CCACCA. Here, we report deep sequencing analysis of the 3' ends of tRNA-Ser-CGA and tRNA-Ser-UGA from S. cerevisiae strains and show that hypomodified mature tRNAs are subjected to CCACCA (or poly(A) addition) as part of a rapid tRNA decay pathway in vivo. We conjecture that CCACCA addtion is a universal mechanism for controlling tRNA levels and preventing errors in translation. 121 samples analyzed in total, representing time courses of 10 different yeast strains; Biological replicates for each time point are included
2011-11-17 | E-GEOD-33756 | biostudies-arrayexpress
Project description:Plant basic helix-loop-helix (bHLH) transcription factors are involved in physiological and developmental processes, and also play essential roles in abiotic stresses. However, their exact roles in abiotic stress are still need to be elucidated, and most of bHLHs have not been functionally characterized. In the present study, we characterized the functional role of AtbHLH112 in response to abiotic stresses. AtbHLH112 is a nuclear-localized protein, and its nuclear-localization is induced by salt, drought and ABA. Besides binding to E-box motif, AtbHLH112 is found to bind to a novel motif with the sequence “GG[GT]CC[GT][GA][TA]C” (GCG-box), and the binding affinity is induced by salt and ABA. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by upregulating the expression of P5CS genes and decreasing the expression of P5CDH and PRODH genes to increase proline levels, and via enhancing the expression of POD and SOD genes to improve ROS scavenging ability. All data together suggested that AtbHLH112 regulates the expression of genes through binding to GCG-box and E-box to mediate the physiological stress responses, including proline biosynthesis and ROS scavenging pathways to enhance stress tolerance.
2014-08-09 | GSE60260 | GEO
Project description:Plant basic helix-loop-helix (bHLH) proteins play essential roles in physiological and developmental processes and are also involved in abiotic stresses. However, their exact roles in abiotic stress are still not fully understood, and most of them have not been functionally characterised. In the present study, we characterised the functional role of AtbHLH112 in response to abiotic stress. A WRKY gene, AtWRKY66, can regulate the expression of the AtbHLH112 via binding to W-box motifs present in its promoter. AtbHLH112 is a nuclear-localised protein, and its nuclear localisation is increased upon exposure to NaCl, mannitol and ABA. In addition to binding to the G-box motif, AtbHLH112 is found to bind to a novel motif “GGGCCGGTC” (named the GCG-box) to regulate gene expression. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with tolerance to salt and drought. AtbHLH112 can confer stress tolerance via enhanced expression of POD and SOD genes to improve ROS scavenging ability and via upregulated expression of P5CS genes and decreased expression of P5CDH and PRODH genes to improve proline levels. Our data suggested that AtbHLH112 regulates the expression of genes via binding to the G-box and the GCG-box to improve stress-related pathways, such as ROS scavenging and proline biosynthesis.
2013-11-14 | GSE52326 | GEO
Project description:Specific environmental insults cause the limited fragmentation of transfer RNAs (tRNAs) into tRNA-derived small RNAs (tsRNAs), which have been implicated in a wide range of biological processes. tRNA fragmentation results from endonucleolytic activities targeting single-stranded tRNA regions. However, how a tRNA with a single hydrolyzed phosphodiester bond in the anticodon loop (‘nicked’ tRNA) gives rise to distinct tsRNAs remains poorly understood. After identifying RNA helicases that were able to unwind ‘nicked’ tRNAs in vitro, the specificity of one of those enzymes, DDX3X, was determined by RNA helicase assays on tRNAs, which had been subjected to recombinant Angiogenin. Both in vivo ‘nicked’ tRNAs, DDX3X-unwound ‘nicked’ tRNAs as well as heat-denatured ‘nicked’ tRNAs were subjected to small RNA sequencing.
2022-04-05 | GSE187021 | GEO