Jekyll & Hyde: Evolution of a Superfamily

SummaryAminoacyl-tRNA synthetase mutations have been linked to neurological diseases, but aminoacylation may be unaffected. This protein superfamily also performs many other diverse functions. Yang et al. insightfully engineer a single mutation to unmask a cell signaling activity of tyrosyl-tRNA synthetase [1]

Diverse cell stresses induce unique patterns of tRNA up- and down-regulation: tRNA-seq for quantifying changes in tRNA copy number

Emerging evidence points to roles for tRNA modifications and tRNA abundance in cellular stress responses. While isolated instances of stress-induced tRNA degradation have been reported, we sought to assess the effects of stress on tRNA levels at a systems level. To this end, we developed a next-generation sequencing method that exploits the paucity of ribonucleoside modifications at the 3′-end of tRNAs to quantify changes in all cellular tRNA molecules. Application of this tRNA-seq method to Saccharomyces cerevisiae identified all 76 expressed unique tRNA species out of 295 coded in the yeast genome, including all isoacceptor variants, with highly precise relative (fold-change) quantification of tRNAs. In studies of stress-induced changes in tRNA levels, we found that oxidation (H[subscript 2]O[subscript 2]) and alkylation (methylmethane sulfonate, MMS) stresses induced nearly identical patterns of up- and down-regulation for 58 tRNAs. However, 18 tRNAs showed opposing changes for the stresses, which parallels our observation of signature reprogramming of tRNA modifications caused by H[subscript 2]O[subscript 2] and MMS. Further, stress-induced degradation was limited to only a small proportion of a few tRNA species. With tRNA-seq applicable to any organism, these results suggest that translational control of stress response involves a contribution from tRNA abundance.National Institutes of Health (U.S.) (ES017010)National Institutes of Health (U.S.) (ES002109)National Science Foundation (U.S.) (CHE-1308839)Singapore-MIT Alliance for Research and Technolog

Mycobacterial RNA isolation optimized for non-coding RNA: high fidelity isolation of 5S rRNA from Mycobacterium bovis BCG reveals novel post-transcriptional processing and a complete spectrum of modified ribonucleosides

A major challenge in the study of mycobacterial RNA biology is the lack of a comprehensive RNA isolation method that overcomes the unusual cell wall to faithfully yield the full spectrum of non-coding RNA (ncRNA) species. Here, we describe a simple and robust procedure optimized for the isolation of total ncRNA, including 5S, 16S and 23S ribosomal RNA (rRNA) and tRNA, from mycobacteria, using Mycobacterium bovis BCG to illustrate the method. Based on a combination of mechanical disruption and liquid and solid-phase technologies, the method produces all major species of ncRNA in high yield and with high integrity, enabling direct chemical and sequence analysis of the ncRNA species. The reproducibility of the method with BCG was evident in bioanalyzer electrophoretic analysis of isolated RNA, which revealed quantitatively significant differences in the ncRNA profiles of exponentially growing and non-replicating hypoxic bacilli. The method also overcame an historical inconsistency in 5S rRNA isolation, with direct sequencing revealing a novel post-transcriptional processing of 5S rRNA to its functional form and with chemical analysis revealing seven post-transcriptional ribonucleoside modifications in the 5S rRNA. This optimized RNA isolation procedure thus provides a means to more rigorously explore the biology of ncRNA species in mycobacteria.Singapore-MIT Alliance for Research and TechnologyNational Institute of Environmental Health Sciences (ES017010)National Institute of Environmental Health Sciences (ES002109)Singapore-MIT Alliance (Graduate Fellowship)Singapore. National Research Foundatio

A multidimensional platform for the purification of non-coding RNA species

A renewed interest in non-coding RNA (ncRNA) has led to the discovery of novel RNA species and post-transcriptional ribonucleoside modifications, and an emerging appreciation for the role of ncRNA in RNA epigenetics. Although much can be learned by amplification-based analysis of ncRNA sequence and quantity, there is a significant need for direct analysis of RNA, which has led to numerous methods for purification of specific ncRNA molecules. However, no single method allows purification of the full range of cellular ncRNA species. To this end, we developed a multidimensional chromatographic platform to resolve, isolate and quantify all canonical ncRNAs in a single sample of cells or tissue, as well as novel ncRNA species. The applicability of the platform is demonstrated in analyses of ncRNA from bacteria, human cells and plasmodium-infected reticulocytes, as well as a viral RNA genome. Among the many potential applications of this platform are a system-level analysis of the dozens of modified ribonucleosides in ncRNA, characterization of novel long ncRNA species, enhanced detection of rare transcript variants and analysis of viral genomes.Singapore-MIT Alliance for Research and TechnologyNational Institute of Environmental Health Sciences (ES017010)National Institute of Environmental Health Sciences (ES002109

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Characterization of leucyl-TRNA synthetase from homo sapiens and escherichia coli in aminoacylation, amino acid editing and interdomain interactions

Aminoacyl-tRNA synthetases (aaRSs) are ancient enzymes that charge tRNA with its cognate amino acid. In order to maintain fidelity during protein synthesis, editing mechanisms ensure that tRNAs are accurately charged. Leucyl-tRNA synthetase (LeuRS) has an editing active site that resides in a discrete domain called the connective polypeptide 1 domain (CP1). Post-transfer editing involves the translocation of mischarged tRNA from the aminoacylation to the editing active site where mischarged tRNA binds for hydrolysis of the noncognate amino acid to enhance fidelity. Based on crystal structure analysis, the CP1 domain rotates 30?? relative to the canonical core where aminoacylation occurs during tRNA translocation and presumably facilitates the movement of tRNA from the core domain to the editing domain. Single molecule fluorescence resonance energy transfer (smFRET) techniques were employed to characterize this dynamic movement of tRNA from one domain of the enzyme to another. Human cytoplasmic LeuRS (hscLeuRS) is typically found in a macromolecular complex containing at least eight other proteins. In order to study this enzyme, hscLeuRS was expressed independent of the complex in Escherichia coli. Enzymatic characterization of the isolated hscLeuRS suggested that it attaches a second leucine to Leu-tRNALeu. Liquid chromatography and mass spectrometry methods were used in an attempt to isolate this hypothesized ???doubly charged??? tRNA species and it is possible that hscLeuRS possesses a secondary function beyond aminoacylation reliant on a doubly charged Leu-Leu-tRNALeu. Further biochemical analysis of the hscLeuRS focused on its editing pocket. The editing site of hscLeuRS includes a highly conserved threonine discriminator and universally conserved aspartic acid that were mutationally characterized. Substitution of threonine to alanine uncoupled specificity similar to other LeuRSs. However, the introduction of bulky residues in the amino acid binding pocket failed to block deacylation of tRNA, indicating that the architecture of the amino acid binding pocket is different compared to other characterized LeuRSs. In addition, mutation of the universally conserved aspartic acid abolished tRNALeu deacylation. Surprisingly though, this editing-defective hscLeuRS maintained fidelity. This indicates that an alternate editing mechanism may have been activated upon failure of the post-transfer editing active site in order to maintain fidelity during protein synthesis

Characterization of Leucyl -Trna Synthetase From Homo Sapiens and Escherichia Coli in Aminoacylation, Amino Acid Editing and Interdomain Interactions

145 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2010.Human cytoplasmic LeuRS (hscLeuRS) is typically found in a macromolecular complex containing at least eight other proteins. In order to study this enzyme, hscLeuRS was expressed independent of the complex in Escherichia coli. Enzymatic characterization of the isolated hscLeuRS suggested that it attaches a second leucine to Leu-tRNALeu. Liquid chromatography and mass spectrometry methods were used in an attempt to isolate this hypothesized "doubly charged" tRNA species and it is possible that hscLeuRS possesses a secondary function beyond aminoacylation reliant on a doubly charged Leu-Leu-tRNALeu. Further biochemical analysis of the hscLeuRS focused on its editing pocket. The editing site of hscLeuRS includes a highly conserved threonine discriminator and universally conserved aspartic acid that were mutationally characterized. Substitution of threonine to alanine uncoupled specificity similar to other LeuRSs. However, the introduction of bulky residues in the amino acid binding pocket failed to block deacylation of tRNA, indicating that the architecture of the amino acid binding pocket is different compared to other characterized LeuRSs. In addition, mutation of the universally conserved aspartic acid abolished tRNALeu deacylation. Surprisingly though, this editing-defective hscLeuRS maintained fidelity. This indicates that an alternate editing mechanism may have been activated upon failure of the post-transfer editing active site in order to maintain fidelity during protein synthesis.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Characterization of Leucyl -Trna Synthetase From Homo Sapiens and Escherichia Coli in Aminoacylation, Amino Acid Editing and Interdomain Interactions

145 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2010.Human cytoplasmic LeuRS (hscLeuRS) is typically found in a macromolecular complex containing at least eight other proteins. In order to study this enzyme, hscLeuRS was expressed independent of the complex in Escherichia coli. Enzymatic characterization of the isolated hscLeuRS suggested that it attaches a second leucine to Leu-tRNALeu. Liquid chromatography and mass spectrometry methods were used in an attempt to isolate this hypothesized "doubly charged" tRNA species and it is possible that hscLeuRS possesses a secondary function beyond aminoacylation reliant on a doubly charged Leu-Leu-tRNALeu. Further biochemical analysis of the hscLeuRS focused on its editing pocket. The editing site of hscLeuRS includes a highly conserved threonine discriminator and universally conserved aspartic acid that were mutationally characterized. Substitution of threonine to alanine uncoupled specificity similar to other LeuRSs. However, the introduction of bulky residues in the amino acid binding pocket failed to block deacylation of tRNA, indicating that the architecture of the amino acid binding pocket is different compared to other characterized LeuRSs. In addition, mutation of the universally conserved aspartic acid abolished tRNALeu deacylation. Surprisingly though, this editing-defective hscLeuRS maintained fidelity. This indicates that an alternate editing mechanism may have been activated upon failure of the post-transfer editing active site in order to maintain fidelity during protein synthesis.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD