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Hideko Kaji - One of the best experts on this subject based on the ideXlab platform.
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59 PUBLICATIONS 1,592 CITATIONS SEE PROFILE
2016Co-Authors: Hideko Kaji, Kazuei IgarashiAbstract:Hirokawa, G. et al. The role of Ribosome Recycling Factor in dissociation of 70S Ribosomes into subunits. RNA 11, 1317-132
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Initiation Factor 3 (IF3) does not have any Role in the Release of Messenger RNA and Transfer RNA from the Post-Termination Complex during the Ribosome Recycling Reaction Catalyzed by EF-G/GTP and RRF (Ribosome Recycling Factor)
Biophysical Journal, 2013Co-Authors: Akira Kaji, Nobuhiro Iwakura, Hideko KajiAbstract:At the end of translation of an ORF, the Ribosome meets the termination codon and peptides are released by release Factors 1, 2 and 3. The resulting post-termination complex (PoTC) is characterized to have one tRNA and mRNA per Ribosome. We showed that it is disassembled by RRF and EF-G/GTP into mRNA, tRNA, and subunits (JBC, 1973, 248, 7580). On the other hand, others claimed that RRF and EF-G split the Ribosome but do not release mRNA or tRNA. IF3 was claimed to be necessary to release mRNA and/or tRNA from the complex of 30S/tRNA/mRNA. This wrong conclusion is due to the use of short ORF with strong SD sequence (Mol Cell., 2005, 18, 675; Mol Cell., 2005, 18, 403). We use more natural PoTC which is free of the influence of the SD sequence, and show here that IF3 has no role in the release of mRNA and tRNA from the PoTC. We (RNA, 2005, 8, 1317) and others showed that splitting of subunits occurs due to RRF and EF-G. It has been known that IF3 prevents association of subunits. However, its effect on the rate of ribosomal splitting by EF-G/RRF remains to be elucidated. In this paper, we will present the results which shed lights on this question.
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Protein synthesis Factors (RF1, RF2, RF3, RRF, and tmRNA) and peptidyl-tRNA hydrolase rescue stalled Ribosomes at sense codons.
Journal of Molecular Biology, 2012Co-Authors: Serafín Vivanco-domínguez, José G. Bueno-martínez, Gloria León-Ávila, Nobuhiro Iwakura, Hideko Kaji, Akira Kaji, Gabriel GuarnerosAbstract:Abstract During translation, Ribosomes stall on mRNA when the aminoacyl-tRNA to be read is not readily available. The stalled Ribosomes are deleterious to the cell and should be rescued to maintain its viability. To investigate the contribution of some of the cellular translation Factors on Ribosome rescuing, we provoked stalling at AGA codons in mutants that affected the Factors and then analyzed the accumulation of oligopeptidyl (peptides of up to 6 amino acid residues, oligopep-)-tRNA or polypeptidyl (peptides of more than 300 amino acids in length, polypep-)-tRNA associated with Ribosomes. Stalling was achieved by starvation for aminoacyl-tRNA Arg4 upon induced expression of engineered lac Z (β-ga lac tosidase) reporter gene harboring contiguous AGA codons close to the initiation codon or at internal codon positions together with minigene ATGAGATAA accompanied by reduced peptidyl-tRNA hydrolase (Pth). Our results showed accumulations of peptidyl-tRNA associated with Ribosomes in mutants for release Factors (RF1, RF2, and RF3), Ribosome Recycling Factor (RRF), Pth, and transfer-messenger RNA (tmRNA), implying that each of these Factors cooperate in rescuing stalled Ribosomes. The role of these Factors in Ribosome releasing from the stalled complex may vary depending on the length of the peptide in the peptidyl-tRNA. RF3 and RRF rescue stalled Ribosomes by “drop-off” of peptidyl-tRNA, while RF1, RF2 (in the absence of termination codon), or Pth may rescue by hydrolyzing the associated peptidyl-tRNA. This is followed by the disassembly of the ribosomal complex of tRNA and mRNA by RRF and elongation Factor G.
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The role of GTP in transient splitting of 70S Ribosomes by RRF (Ribosome Recycling Factor) and EF-G (elongation Factor G)
Nucleic acids research, 2008Co-Authors: Go Hirokawa, Nobuhiro Iwakura, Akira Kaji, Hideko KajiAbstract:Ribosome Recycling Factor (RRF), elongation Factor G (EF-G) and GTP split 70S Ribosomes into subunits. Here, we demonstrated that the splitting was transient and the exhaustion of GTP resulted in re-association of the split subunits into 70S Ribosomes unless IF3 (initiation Factor 3) was present. However, the splitting was observed with sucrose density gradient centrifugation (SDGC) without IF3 if RRF, EF-G and GTP were present in the SDGC buffer. The splitting of 70S Ribosomes causes the decrease of light scattering by Ribosomes. Kinetic constants obtained from the light scattering studies are sufficient to account for the splitting of 70S Ribosomes by RRF and EF-G/GTP during the lag phase for activation of Ribosomes for the log phase. As the amount of 70S Ribosomes increased, more RRF, EF-G and GTP were necessary to split 70S Ribosomes. In the presence of a physiological amount of polyamines, GTP and Factors, even 0.6 μM 70S Ribosomes (12 times higher than the 70S Ribosomes for routine assay) were split. Spermidine (2 mM) completely inhibited anti-association activity of IF3, and the RRF/EF-G/GTP-dependent splitting of 70S Ribosomes.
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Release of Ribosome-bound Ribosome Recycling Factor by Elongation Factor G
The Journal of biological chemistry, 2003Co-Authors: Michael C. Kiel, Hideko Kaji, V. Samuel Raj, Akira KajiAbstract:Elongation Factor G (EF-G) and Ribosome Recycling Factor (RRF) disassemble post-termination complexes of Ribosome, mRNA, and tRNA. RRF forms stable complexes with 70 S Ribosomes and 50 S ribosomal subunits. Here, we show that EF-G releases RRF from 70 S ribosomal and model post-termination complexes but not from 50 S ribosomal subunit complexes. The release of bound RRF by EF-G is stimulated by GTP analogues. The EF-G-dependent release occurs in the presence of fusidic acid and viomycin. However, thiostrepton inhibits the release. RRF was shown to bind to EF-G-Ribosome complexes in the presence of GTP with much weaker affinity, suggesting that EF-G may move RRF to this position during the release of RRF. On the other hand, RRF did not bind to EF-G-Ribosome complexes with fusidic acid, suggesting that EF-G stabilized by fusidic acid does not represent the natural post-termination complex. In contrast, the complexes of Ribosome, EF-G and thiostrepton could bind RRF, although with lower affinity. These results suggest that thiostrepton traps an intermediate complex having RRF on a position that clashes with the P/E site bound tRNA. Mutants of EF-G that are impaired for translocation fail to disassemble post-termination complexes and exhibit lower activity in releasing RRF. We propose that the release of Ribosome-bound RRF by EF-G is required for post-termination complex disassembly. Before release from the Ribosome, the position of RRF on the Ribosome will change from the original A/P site to a new location that clashes with tRNA on the P/E site.
Akira Kaji - One of the best experts on this subject based on the ideXlab platform.
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chemical and structural characterization of a model post termination complex potc for the Ribosome Recycling reaction evidence for the release of the mrna by rrf and ef g
PLOS ONE, 2017Co-Authors: Nobuhiro Iwakura, Takeshi Yokoyama, Fabio Quaglia, Kaoru Mitsuoka, Kazuhiro Mio, Hideki Shigematsu, Mikako Shirouzu, Akira KajiAbstract:A model Post-Termination Complex (PoTC) used for the discovery of Ribosome Recycling Factor (RRF) was purified and characterized by cryo-electron microscopic analysis and biochemical methods. We established that the model PoTC has mostly one tRNA, at the P/E or P/P position, together with one mRNA. The structural studies were supported by the biochemical measurement of bound tRNA and mRNA. Using this substrate, we establish that the release of tRNA, release of mRNA and splitting of ribosomal subunits occur during the Recycling reaction. Order of these events is tRNA release first followed by mRNA release and splitting almost simultaneously. Moreover, we demonstrate that IF3 is not involved in any of the Recycling reactions but simply prevents the re-association of split ribosomal subunits. Our finding demonstrates that the important function of RRF includes the release of mRNA, which is often missed by the use of a short ORF with the Shine-Dalgarno sequence near the termination site.
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Initiation Factor 3 (IF3) does not have any Role in the Release of Messenger RNA and Transfer RNA from the Post-Termination Complex during the Ribosome Recycling Reaction Catalyzed by EF-G/GTP and RRF (Ribosome Recycling Factor)
Biophysical Journal, 2013Co-Authors: Akira Kaji, Nobuhiro Iwakura, Hideko KajiAbstract:At the end of translation of an ORF, the Ribosome meets the termination codon and peptides are released by release Factors 1, 2 and 3. The resulting post-termination complex (PoTC) is characterized to have one tRNA and mRNA per Ribosome. We showed that it is disassembled by RRF and EF-G/GTP into mRNA, tRNA, and subunits (JBC, 1973, 248, 7580). On the other hand, others claimed that RRF and EF-G split the Ribosome but do not release mRNA or tRNA. IF3 was claimed to be necessary to release mRNA and/or tRNA from the complex of 30S/tRNA/mRNA. This wrong conclusion is due to the use of short ORF with strong SD sequence (Mol Cell., 2005, 18, 675; Mol Cell., 2005, 18, 403). We use more natural PoTC which is free of the influence of the SD sequence, and show here that IF3 has no role in the release of mRNA and tRNA from the PoTC. We (RNA, 2005, 8, 1317) and others showed that splitting of subunits occurs due to RRF and EF-G. It has been known that IF3 prevents association of subunits. However, its effect on the rate of ribosomal splitting by EF-G/RRF remains to be elucidated. In this paper, we will present the results which shed lights on this question.
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Protein synthesis Factors (RF1, RF2, RF3, RRF, and tmRNA) and peptidyl-tRNA hydrolase rescue stalled Ribosomes at sense codons.
Journal of Molecular Biology, 2012Co-Authors: Serafín Vivanco-domínguez, José G. Bueno-martínez, Gloria León-Ávila, Nobuhiro Iwakura, Hideko Kaji, Akira Kaji, Gabriel GuarnerosAbstract:Abstract During translation, Ribosomes stall on mRNA when the aminoacyl-tRNA to be read is not readily available. The stalled Ribosomes are deleterious to the cell and should be rescued to maintain its viability. To investigate the contribution of some of the cellular translation Factors on Ribosome rescuing, we provoked stalling at AGA codons in mutants that affected the Factors and then analyzed the accumulation of oligopeptidyl (peptides of up to 6 amino acid residues, oligopep-)-tRNA or polypeptidyl (peptides of more than 300 amino acids in length, polypep-)-tRNA associated with Ribosomes. Stalling was achieved by starvation for aminoacyl-tRNA Arg4 upon induced expression of engineered lac Z (β-ga lac tosidase) reporter gene harboring contiguous AGA codons close to the initiation codon or at internal codon positions together with minigene ATGAGATAA accompanied by reduced peptidyl-tRNA hydrolase (Pth). Our results showed accumulations of peptidyl-tRNA associated with Ribosomes in mutants for release Factors (RF1, RF2, and RF3), Ribosome Recycling Factor (RRF), Pth, and transfer-messenger RNA (tmRNA), implying that each of these Factors cooperate in rescuing stalled Ribosomes. The role of these Factors in Ribosome releasing from the stalled complex may vary depending on the length of the peptide in the peptidyl-tRNA. RF3 and RRF rescue stalled Ribosomes by “drop-off” of peptidyl-tRNA, while RF1, RF2 (in the absence of termination codon), or Pth may rescue by hydrolyzing the associated peptidyl-tRNA. This is followed by the disassembly of the ribosomal complex of tRNA and mRNA by RRF and elongation Factor G.
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The role of GTP in transient splitting of 70S Ribosomes by RRF (Ribosome Recycling Factor) and EF-G (elongation Factor G)
Nucleic acids research, 2008Co-Authors: Go Hirokawa, Nobuhiro Iwakura, Akira Kaji, Hideko KajiAbstract:Ribosome Recycling Factor (RRF), elongation Factor G (EF-G) and GTP split 70S Ribosomes into subunits. Here, we demonstrated that the splitting was transient and the exhaustion of GTP resulted in re-association of the split subunits into 70S Ribosomes unless IF3 (initiation Factor 3) was present. However, the splitting was observed with sucrose density gradient centrifugation (SDGC) without IF3 if RRF, EF-G and GTP were present in the SDGC buffer. The splitting of 70S Ribosomes causes the decrease of light scattering by Ribosomes. Kinetic constants obtained from the light scattering studies are sufficient to account for the splitting of 70S Ribosomes by RRF and EF-G/GTP during the lag phase for activation of Ribosomes for the log phase. As the amount of 70S Ribosomes increased, more RRF, EF-G and GTP were necessary to split 70S Ribosomes. In the presence of a physiological amount of polyamines, GTP and Factors, even 0.6 μM 70S Ribosomes (12 times higher than the 70S Ribosomes for routine assay) were split. Spermidine (2 mM) completely inhibited anti-association activity of IF3, and the RRF/EF-G/GTP-dependent splitting of 70S Ribosomes.
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Release of Ribosome-bound Ribosome Recycling Factor by Elongation Factor G
The Journal of biological chemistry, 2003Co-Authors: Michael C. Kiel, Hideko Kaji, V. Samuel Raj, Akira KajiAbstract:Elongation Factor G (EF-G) and Ribosome Recycling Factor (RRF) disassemble post-termination complexes of Ribosome, mRNA, and tRNA. RRF forms stable complexes with 70 S Ribosomes and 50 S ribosomal subunits. Here, we show that EF-G releases RRF from 70 S ribosomal and model post-termination complexes but not from 50 S ribosomal subunit complexes. The release of bound RRF by EF-G is stimulated by GTP analogues. The EF-G-dependent release occurs in the presence of fusidic acid and viomycin. However, thiostrepton inhibits the release. RRF was shown to bind to EF-G-Ribosome complexes in the presence of GTP with much weaker affinity, suggesting that EF-G may move RRF to this position during the release of RRF. On the other hand, RRF did not bind to EF-G-Ribosome complexes with fusidic acid, suggesting that EF-G stabilized by fusidic acid does not represent the natural post-termination complex. In contrast, the complexes of Ribosome, EF-G and thiostrepton could bind RRF, although with lower affinity. These results suggest that thiostrepton traps an intermediate complex having RRF on a position that clashes with the P/E site bound tRNA. Mutants of EF-G that are impaired for translocation fail to disassemble post-termination complexes and exhibit lower activity in releasing RRF. We propose that the release of Ribosome-bound RRF by EF-G is required for post-termination complex disassembly. Before release from the Ribosome, the position of RRF on the Ribosome will change from the original A/P site to a new location that clashes with tRNA on the P/E site.
Umesh Varshney - One of the best experts on this subject based on the ideXlab platform.
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Microbiology (2002), 148, 3913–3920 Printed in Great Britain Characterization of Mycobacterium
2015Co-Authors: Arasada Rajeswara Rao, Umesh VarshneyAbstract:tuberculosis Ribosome Recycling Factor (RRF) and a mutant lacking six amino acids from the C-terminal end reveals that the C-terminal residues are important for its occupancy on the ribosom
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an extended shine dalgarno sequence in mrna functionally bypasses a vital defect in initiator trna
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Sunil Shetty, Himapriyanka Nadimpalli, Riyaz Ahmad Shah, Smriti Arora, Umesh VarshneyAbstract:Initiator tRNAs are special in their direct binding to the ribosomal P-site due to the hallmark occurrence of the three consecutive G-C base pairs (3GC pairs) in their anticodon stems. How the 3GC pairs function in this role, has remained unsolved. We show that mutations in either the mRNA or 16S rRNA leading to extended interaction between the Shine–Dalgarno (SD) and anti-SD sequences compensate for the vital need of the 3GC pairs in tRNAfMet for its function in Escherichia coli. In vivo, the 3GC mutant tRNAfMet occurred less abundantly in 70S Ribosomes but normally on 30S subunits. However, the extended SD:anti-SD interaction increased its occurrence in 70S Ribosomes. We propose that the 3GC pairs play a critical role in tRNAfMet retention in Ribosome during the conformational changes that mark the transition of 30S preinitiation complex into elongation competent 70S complex. Furthermore, treating cells with kasugamycin, decreasing Ribosome Recycling Factor (RRF) activity or increasing initiation Factor 2 (IF2) levels enhanced initiation with the 3GC mutant tRNAfMet, suggesting that the 70S mode of initiation is less dependent on the 3GC pairs in tRNAfMet.
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Recycling of ribosomal complexes stalled at the step of elongation in escherichia coli
Journal of Molecular Biology, 2008Co-Authors: N Singh, Rais Ahmad, Ramachandran Sangeetha, Umesh VarshneyAbstract:Translating Ribosomes often stall during elongation. The stalled Ribosomes are known to be recycled by tmRNA (SsrA)-mediated trans-translation.Another process that recycles the stalled Ribosomes is characterized by peptidyl-tRNA release. However, the mechanism of peptidyl-tRNA release from the stalled Ribosomes is not well understood.We used a defined system of an AGA-minigene containing a small open reading frame (ATG AGA AGA). Translation of the AGA- inigene mRNA is toxic to Escherichia coli because it stalls Ribosomes during elongation and sequesters $tRNA^{Arg4}$ as a short-chain peptidyl-$tRNA^{Arg4}$ in the ribosomal P-site. We show that a Ribosome Recycling Factor (RRF)-mediated process rescues the host from the AGA-minigene toxicity by releasing the peptidyl-$tRNA^{Arg4}$ from the Ribosomes. The growth phenotypes of E. coli strains harboring mutant alleles of RRF and initiation Factor 3 (IF3) genes and their consequences on \lambda immP22 phage replication upon AGA-minigene expression reveal that IF3 facilitates the RRF-mediated processing of the stalled Ribosomes. Additionally, we have designed a uracil DNA glycosylase gene construct, ung-stopless, whose expression is toxic to E. coli. We show that the RRF-mediated process also alleviates the ung-stopless construct-mediated toxicity to the host by releasing the ung mRNA from the Ribosomes harboring long-chain peptidyl-tRNAs.
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evidence for a role of initiation Factor 3 in Recycling of ribosomal complexes stalled on mrnas in escherichia coli
Nucleic Acids Research, 2005Co-Authors: N Singh, Ramachandran Sangeetha, Gautam Das, Anuradha Seshadri, Umesh VarshneyAbstract:Specific interactions between Ribosome Recycling Factor (RRF) and elongation Factor-G (EFG) mediate disassembly of post-termination ribosomal complexes for new rounds of initiation. The interactions between RRF and EFG are also important in peptidyl-tRNA release from stalled pre-termination complexes. Unlike the post-termination complexes (harboring deacylated tRNA), the pre-termination complexes (harboring peptidyl-tRNA) are not recycled by RRF and EFG in vitro, suggesting participation of additional Factor(s) in the process. Using a combination of biochemical and genetic approaches, we show that, (i) Inclusion of IF3 with RRF and EFG results in Recycling of the pre-termination complexes; (ii) IF3 overexpression in Escherichia coli LJ14 rescues its temperature sensitive phenotype for RRF; (iii) Transduction of infC135 (which encodes a functionally compromised IF3) in E.coli LJ14 generates a 'synthetic severe' phenotype; (iv) The infC135 and frr1 (containing an insertion in the RRF gene promoter) alleles synergistically rescue a temperature sensitive mutation in peptidyl-tRNA hydrolase in E.coli; and (v) IF3 facilitates Ribosome Recycling by Thermus thermophilus RRF and E.coli EFG in vivo and in vitro. These lines of evidence clearly demonstrate the physiological importance of IF3 in the overall mechanism of Ribosome Recycling in E.coli.
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a physiological connection between tmrna and peptidyl trna hydrolase functions in escherichia coli
Nucleic Acids Research, 2004Co-Authors: N Singh, Umesh VarshneyAbstract:The bacterial ssrA gene codes for a dual function RNA, tmRNA, which possesses tRNA-like and mRNA-like regions. The tmRNA appends an oligopeptide tag to the polypeptide on the P-site tRNA by a trans-translation process that rescues Ribosomes stalled on the mRNAs and targets the aberrant protein for degradation. In cells, processing of the stalled Ribosomes is also pioneered by drop-off of peptidyl-tRNAs. The ester bond linking the peptide to tRNA is hydrolyzed by peptidyl-tRNA hydrolase (Pth), an essential enzyme, which releases the tRNA and the aberrant peptide. As the trans-translation mechanism utilizes the peptidyl-transferase activity of the stalled Ribosomes to free the tRNA (as opposed to peptidyl-tRNA drop-off), the need for Pth to recycle such tRNAs is bypassed. Thus, we hypothesized that tmRNA may rescue a defect in Pth. Here, we show that overexpression of tmRNA rescues the temperature-sensitive phenotype of Escherichia coli (pth(ts)). Conversely, a null mutation in ssrA enhances the temperature-sensitive phenotype of the pth(ts) strain. Consistent with our hypothesis, overexpression of tmRNA results in decreased accumulation of peptidyl-tRNA in E.coli. Furthermore, overproduction of tmRNA in E.coli strains deficient in Ribosome Recycling Factor and/or lacking the release Factor 3 enhances the rescue of pth(ts) strains. We discuss the physiological relevance of these observations to highlight a major role of tmRNA in decreasing cellular peptidyl-tRNA load.
Miguel A De Barros Lopes - One of the best experts on this subject based on the ideXlab platform.
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Polymorphisms in the Mitochondrial Ribosome Recycling Factor EF-G2mt/MEF2 Compromise Cell Respiratory Function and Increase Atorvastatin Toxicity
2016Co-Authors: Sylvie Callegari, Philip A Gregory, Matthew J Sykes, Stuart Andrews, Ross A Mckinnon, Jennifer Bellon, Miguel A De Barros LopesAbstract:Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation Factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial Ribosome Recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphism
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polymorphisms in the mitochondrial Ribosome Recycling Factor ef g2mt mef2 compromise cell respiratory function and increase atorvastatin toxicity
PLOS Genetics, 2012Co-Authors: Sylvie Callegari, Philip A Gregory, Matthew J Sykes, Jennifer R Bellon, Stuart Andrews, Ross A Mckinnon, Miguel A De Barros LopesAbstract:Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation Factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial Ribosome Recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphisms (SNPs) in the EF-G2mt gene, were generated in the yeast MEF2 gene. Although these mutations do not produce an obvious growth phenotype, three mutations reveal an atorvastatin-sensitive phenotype and further analysis uncovers a decreased respiratory capacity. These findings constitute the first reported phenotype associated with SNPs in the EF-G2mt gene and implicate the human EF-G2mt gene as a pharmacogenetic candidate gene for statin toxicity in humans.
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Polymorphisms in the Mitochondrial Ribosome Recycling Factor EF-G2mt/MEF2 Compromise Cell Respiratory Function and Increase Atorvastatin Toxicity
2012Co-Authors: Sylvie Callegari, Philip A Gregory, Matthew J Sykes, Stuart Andrews, Ross A Mckinnon, Jennifer Bellon, Miguel A De Barros LopesAbstract:Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation Factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial Ribosome Recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphisms (SNPs) in the EF-G2mt gene, were generated in the yeast MEF2 gene. Although these mutations do not produce an obvious growth phenotype, three mutations reveal an atorvastatin-sensitive phenotype and further analysis uncovers a decreased respiratory capacity. These findings constitute the first reported phenotype associated with SNPs in the EF-G2mt gene and implicate the human EF-G2mt gene as a pharmacogenetic candidate gene for statin toxicity in humans.
Philip A Gregory - One of the best experts on this subject based on the ideXlab platform.
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Polymorphisms in the Mitochondrial Ribosome Recycling Factor EF-G2mt/MEF2 Compromise Cell Respiratory Function and Increase Atorvastatin Toxicity
2016Co-Authors: Sylvie Callegari, Philip A Gregory, Matthew J Sykes, Stuart Andrews, Ross A Mckinnon, Jennifer Bellon, Miguel A De Barros LopesAbstract:Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation Factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial Ribosome Recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphism
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polymorphisms in the mitochondrial Ribosome Recycling Factor ef g2mt mef2 compromise cell respiratory function and increase atorvastatin toxicity
PLOS Genetics, 2012Co-Authors: Sylvie Callegari, Philip A Gregory, Matthew J Sykes, Jennifer R Bellon, Stuart Andrews, Ross A Mckinnon, Miguel A De Barros LopesAbstract:Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation Factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial Ribosome Recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphisms (SNPs) in the EF-G2mt gene, were generated in the yeast MEF2 gene. Although these mutations do not produce an obvious growth phenotype, three mutations reveal an atorvastatin-sensitive phenotype and further analysis uncovers a decreased respiratory capacity. These findings constitute the first reported phenotype associated with SNPs in the EF-G2mt gene and implicate the human EF-G2mt gene as a pharmacogenetic candidate gene for statin toxicity in humans.
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Polymorphisms in the Mitochondrial Ribosome Recycling Factor EF-G2mt/MEF2 Compromise Cell Respiratory Function and Increase Atorvastatin Toxicity
2012Co-Authors: Sylvie Callegari, Philip A Gregory, Matthew J Sykes, Stuart Andrews, Ross A Mckinnon, Jennifer Bellon, Miguel A De Barros LopesAbstract:Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation Factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial Ribosome Recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphisms (SNPs) in the EF-G2mt gene, were generated in the yeast MEF2 gene. Although these mutations do not produce an obvious growth phenotype, three mutations reveal an atorvastatin-sensitive phenotype and further analysis uncovers a decreased respiratory capacity. These findings constitute the first reported phenotype associated with SNPs in the EF-G2mt gene and implicate the human EF-G2mt gene as a pharmacogenetic candidate gene for statin toxicity in humans.
