1
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Eom S, Peak J, Park J, Ahn SH, Cho YK, Jeong Y, Lee HS, Lee J, Ignatova E, Lee SE, Hong Y, Gu D, Kim GWD, Lee DC, Hahm JY, Jeong J, Choi D, Jang ES, Chi SW. Widespread 8-oxoguanine modifications of miRNA seeds differentially regulate redox-dependent cancer development. Nat Cell Biol 2023; 25:1369-1383. [PMID: 37696949 DOI: 10.1038/s41556-023-01209-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/19/2023] [Indexed: 09/13/2023]
Abstract
Oxidative stress contributes to tumourigenesis by altering gene expression. One accompanying modification, 8-oxoguanine (o8G) can change RNA-RNA interactions via o8G•A base pairing, but its regulatory roles remain elusive. Here, on the basis of o8G-induced guanine-to-thymine (o8G > T) variations featured in sequencing, we discovered widespread position-specific o8Gs in tumour microRNAs, preferentially oxidized towards 5' end seed regions (positions 2-8) with clustered sequence patterns and clinically associated with patients in lower-grade gliomas and liver hepatocellular carcinoma. We validated that o8G at position 4 of miR-124 (4o8G-miR-124) and 4o8G-let-7 suppress lower-grade gliomas, whereas 3o8G-miR-122 and 4o8G-let-7 promote malignancy of liver hepatocellular carcinoma by redirecting the target transcriptome to oncogenic regulatory pathways. Stepwise oxidation from tumour-promoting 3o8G-miR-122 to tumour-suppressing 2,3o8G-miR-122 occurs and its specific modulation in mouse liver effectively attenuates diethylnitrosamine-induced hepatocarcinogenesis. These findings provide resources and insights into epitranscriptional o8G regulation of microRNA functions, reprogrammed by redox changes, implicating its control for cancer treatment.
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Affiliation(s)
- Sangkyeong Eom
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Jongjin Peak
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Jongyeun Park
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Seung Hyun Ahn
- Department of Life Sciences, Korea University, Seoul, Korea
| | - You Kyung Cho
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Yeahji Jeong
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Hye-Sook Lee
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Jung Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea
| | | | - Sung Eun Lee
- Department of Life Sciences, Korea University, Seoul, Korea
- Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - Yunji Hong
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Dowoon Gu
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Geun-Woo D Kim
- Department of Life Sciences, Korea University, Seoul, Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea
| | - Dong Chan Lee
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Ja Young Hahm
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Jaemin Jeong
- Department of Surgery, Hanyang University College of Medicine, Seoul, Korea
| | - Dongho Choi
- Department of Surgery, Hanyang University College of Medicine, Seoul, Korea
| | - Eun-Sook Jang
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Sung Wook Chi
- Department of Life Sciences, Korea University, Seoul, Korea.
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea.
- Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
- Medicinal Materials Research Center, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul, Korea.
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2
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Hahm JY, Park J, Jang ES, Chi SW. 8-Oxoguanine: from oxidative damage to epigenetic and epitranscriptional modification. Exp Mol Med 2022; 54:1626-1642. [PMID: 36266447 PMCID: PMC9636213 DOI: 10.1038/s12276-022-00822-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/06/2022] [Accepted: 05/26/2022] [Indexed: 12/29/2022] Open
Abstract
In pathophysiology, reactive oxygen species control diverse cellular phenotypes by oxidizing biomolecules. Among these, the guanine base in nucleic acids is the most vulnerable to producing 8-oxoguanine, which can pair with adenine. Because of this feature, 8-oxoguanine in DNA (8-oxo-dG) induces a G > T (C > A) mutation in cancers, which can be deleterious and thus actively repaired by DNA repair pathways. 8-Oxoguanine in RNA (o8G) causes problems in aberrant quality and translational fidelity, thereby it is subjected to the RNA decay pathway. In addition to oxidative damage, 8-oxo-dG serves as an epigenetic modification that affects transcriptional regulatory elements and other epigenetic modifications. With the ability of o8G•A in base pairing, o8G alters structural and functional RNA-RNA interactions, enabling redirection of posttranscriptional regulation. Here, we address the production, regulation, and function of 8-oxo-dG and o8G under oxidative stress. Primarily, we focus on the epigenetic and epitranscriptional roles of 8-oxoguanine, which highlights the significance of oxidative modification in redox-mediated control of gene expression.
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Affiliation(s)
- Ja Young Hahm
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea
| | - Jongyeun Park
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea
| | - Eun-Sook Jang
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea
| | - Sung Wook Chi
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02481 Republic of Korea
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3
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Phillips CN, Schowe S, Langeberg CJ, Siddique N, Chapman EG, Resendiz MJE. Processing of RNA Containing 8-Oxo-7,8-Dihydroguanosine (8-oxoG) by the Exoribonuclease Xrn-1. Front Mol Biosci 2021; 8:780315. [PMID: 34869601 PMCID: PMC8634602 DOI: 10.3389/fmolb.2021.780315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/21/2021] [Indexed: 12/31/2022] Open
Abstract
Understanding how oxidatively damaged RNA is handled intracellularly is of relevance due to the link between oxidized RNA and the progression/development of some diseases as well as aging. Among the ribonucleases responsible for the decay of modified (chemically or naturally) RNA is the exonuclease Xrn-1, a processive enzyme that catalyzes the hydrolysis of 5′-phosphorylated RNA in a 5′→3′ direction. We set out to explore the reactivity of this exonuclease towards oligonucleotides (ONs, 20-nt to 30-nt long) of RNA containing 8-oxo-7,8-dihydroguanosine (8-oxoG), obtained via solid-phase synthesis. The results show that Xrn-1 stalled at sites containing 8-oxoG, evidenced by the presence of a slower moving band (via electrophoretic analyses) than that observed for the canonical analogue. The observed fragment(s) were characterized via PAGE and MALDI-TOF to confirm that the oligonucleotide fragment(s) contained a 5′-phosphorylated 8-oxoG. Furthermore, the yields for this stalling varied from app. 5–30% with 8-oxoG located at different positions and in different sequences. To gain a better understanding of the decreased nuclease efficiency, we probed: 1) H-bonding and spatial constraints; 2) anti-syn conformational changes; 3) concentration of divalent cation; and 4) secondary structure. This was carried out by introducing methylated or brominated purines (m1G, m6,6A, or 8-BrG), probing varying [Mg2+], and using circular dichroism (CD) to explore the formation of structured RNA. It was determined that spatial constraints imposed by conformational changes around the glycosidic bond may be partially responsible for stalling, however, the results do not fully explain some of the observed higher stalling yields. We hypothesize that altered π-π stacking along with induced H-bonding interactions between 8-oxoG and residues within the binding site may also play a role in the decreased Xrn-1 efficiency. Overall, these observations suggest that other factors, yet to be discovered/established, are likely to contribute to the decay of oxidized RNA. In addition, Xrn-1 degraded RNA containing m1G, and stalled mildly at sites where it encountered m6,6A, or 8-BrG, which is of particular interest given that the former two are naturally occurring modifications.
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Affiliation(s)
- Cheyenne N Phillips
- Department of Chemistry, University of Colorado Denver, Denver, CO, United States
| | - Shawn Schowe
- Department of Chemistry, University of Colorado Denver, Denver, CO, United States
| | - Conner J Langeberg
- Department of Chemistry, University of Denver, Denver, CO, United States
| | - Namoos Siddique
- Department of Chemistry, University of Colorado Denver, Denver, CO, United States
| | - Erich G Chapman
- Department of Chemistry, University of Denver, Denver, CO, United States
| | - Marino J E Resendiz
- Department of Chemistry, University of Colorado Denver, Denver, CO, United States
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4
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Kim SC, O'Flaherty DK, Giurgiu C, Zhou L, Szostak JW. The Emergence of RNA from the Heterogeneous Products of Prebiotic Nucleotide Synthesis. J Am Chem Soc 2021; 143:3267-3279. [PMID: 33636080 DOI: 10.1021/jacs.0c12955] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent advances in prebiotic chemistry are beginning to outline plausible pathways for the synthesis of the canonical ribonucleotides and their assembly into oligoribonucleotides. However, these reaction pathways suggest that many noncanonical nucleotides are likely to have been generated alongside the standard ribonucleotides. Thus, the oligomerization of prebiotically synthesized nucleotides is likely to have led to a highly heterogeneous collection of oligonucleotides comprised of a wide range of types of nucleotides connected by a variety of backbone linkages. How then did relatively homogeneous RNA emerge from this primordial heterogeneity? Here we focus on nonenzymatic template-directed primer extension as a process that would have strongly enriched for homogeneous RNA over the course of multiple cycles of replication. We review the effects on copying the kinetics of nucleotides with altered nucleobase and sugar moieties, when they are present as activated monomers and when they are incorporated into primer and template oligonucleotides. We also discuss three variations in backbone connectivity, all of which are nonheritable and regenerate native RNA upon being copied. The kinetic superiority of RNA synthesis suggests that nonenzymatic copying served as a chemical selection mechanism that allowed relatively homogeneous RNA to emerge from a complex mixture of prebiotically synthesized nucleotides and oligonucleotides.
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Affiliation(s)
- Seohyun Chris Kim
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Derek K O'Flaherty
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Constantin Giurgiu
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Lijun Zhou
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
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5
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Skinner A, Yang C, Hincks K, Wang H, Resendiz MJE. Experimental and theoretical rationalization for the base pairing abilities of inosine, guanosine, adenosine, and their corresponding 8-oxo-7,8-dihydropurine, and 8-bromopurine analogues within A-form duplexes of RNA. Biopolymers 2020; 111:e23410. [PMID: 33216981 PMCID: PMC7780609 DOI: 10.1002/bip.23410] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/30/2020] [Accepted: 11/09/2020] [Indexed: 12/13/2022]
Abstract
Inosine is an important RNA modification, furthermore RNA oxidation has gained interest due, in part, to its potential role in the development/progression of disease as well as on its impact on RNA structure and function. In this report we established the base pairing abilities of purine nucleobases G, I, A, as well as their corresponding, 8-oxo-7,8-dihydropurine (common products of oxidation at the C8-position of purines), and 8-bromopurine (as probes to explore conformational changes), derivatives, namely 8-oxoG, 8-oxoI, 8-oxoA, 8-BrG, and 8-BrI. Dodecamers of RNA were obtained using standard phosphoramidite chemistry via solid-phase synthesis, and used as models to establish the impact that each of these nucleobases have on the thermal stability of duplexes, when base pairing to canonical and noncanonical nucleobases. Thermal stabilities were obtained from thermal denaturation transition (Tm ) measurements, via circular dichroism (CD). The results were then rationalized using models of base pairs between two monomers, via density functional theory (DFT), that allowed us to better understand potential contributions from H-bonding patterns arising from distinct conformations. Overall, some of the important results indicate that: (a) an anti-I:syn-A base pair provides thermal stability, due to the absence of the exocyclic amine; (b) 8-oxoG base pairs like U, and does not induce destabilization within the duplex when compared to the pyrimidine ring; (c) a U:G wobble-pair is only stabilized by G; and (d) 8-oxoA displays an inherited base pairing promiscuity in this sequence context. Gaining a better understanding of how this oxidatively generated lesions potentially base pair with other nucleobases will be useful to predict various biological outcomes, as well as in the design of biomaterials and/or nucleotide derivatives with biological potential.
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Affiliation(s)
- Austin Skinner
- Department of ChemistryUniversity of Colorado DenverDenverColoradoUSA
| | - Chou‐Hsun Yang
- Department of ChemistryUniversity of Colorado DenverDenverColoradoUSA
| | - Kazuki Hincks
- Department of ChemistryUniversity of Colorado DenverDenverColoradoUSA
| | - Haobin Wang
- Department of ChemistryUniversity of Colorado DenverDenverColoradoUSA
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6
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Translesion synthesis by AMV, HIV, and MMLVreverse transcriptases using RNA templates containing inosine, guanosine, and their 8-oxo-7,8-dihydropurine derivatives. PLoS One 2020; 15:e0235102. [PMID: 32857764 PMCID: PMC7455023 DOI: 10.1371/journal.pone.0235102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/07/2020] [Indexed: 12/31/2022] Open
Abstract
Inosine is ubiquitous and essential in many biological processes, including RNA-editing. In addition, oxidative stress on RNA has been a topic of increasing interest due, in part, to its potential role in the development/progression of disease. In this work we probed the ability of three reverse transcriptases (RTs) to catalyze the synthesis of cDNA in the presence of RNA templates containing inosine (I), 8-oxo-7,8-dihydroinosine (8oxo-I), guanosine (G), or 8-oxo-7,8-dihydroguanosine (8-oxoG), and explored the impact that these purine derivatives have as a function of position. To this end, we used 29-mers of RNA (as template) containing the modifications at position-18 and reverse transcribed DNA using 17-mers, 18-mers, or 19-mers (as primers). Generally reactivity of the viral RTs, AMV / HIV / MMLV, towards cDNA synthesis was similar for templates containing G or I as well as for those with 8-oxoG or 8-oxoI. Notable differences are: 1) the use of 18-mers of DNA (to explore cDNA synthesis past the lesion/modification) led to inhibition of DNA elongation in cases where a G:dA wobble pair was present, while the presence of I, 8-oxoI, or 8-oxoG led to full synthesis of the corresponding cDNA, with the latter two displaying a more efficient process; 2) HIV RT is more sensitive to modified base pairs in the vicinity of cDNA synthesis; and 3) the presence of a modification two positions away from transcription initiation has an adverse impact on the overall process. Steady-state kinetics were established using AMV RT to determine substrate specificities towards canonical dNTPs (N = G, C, T, A). Overall we found evidence that RNA templates containing inosine are likely to incorporate dC > dT > > dA, where reactivity in the presence of dA was found to be pH dependent (process abolished at pH 7.3); and that the absence of the C2-exocyclic amine, as displayed with templates containing 8-oxoI, leads to increased selectivity towards incorporation of dA over dC. The data will be useful in assessing the impact that the presence of inosine and/or oxidatively generated lesions have on viral processes and adds to previous reports where I codes exclusively like G. Similar results were obtained upon comparison of AMV and MMLV RTs.
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7
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Kiggins C, Skinner A, Resendiz MJE. 7,8-Dihydro-8-oxoguanosine Lesions Inhibit the Theophylline Aptamer or Change Its Selectivity. Chembiochem 2020; 21:1347-1355. [PMID: 31845489 PMCID: PMC7297664 DOI: 10.1002/cbic.201900684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Indexed: 12/15/2022]
Abstract
Aptamers are attractive constructs due to their high affinity/selectivity towards a target. Here 7,8-dihydro-8-oxoguanosine (8-oxoG) has been used, due in part to its unique H-bonding capabilities (Watson-Crick or Hoogsteen), to expand the "RNA alphabet". Its impact on the theophylline RNA aptamer was explored by modifying its binding pocket at positions G11, G25, or G26. Structural probing, with RNases A and T1 , showed that modification at G11 leads to a drastic structural change, whereas the G25-/G26-modified analogues exhibited cleavage patterns similar to that of the canonical construct. The recognition properties towards three xanthine derivatives were then explored through thermophoresis. Modifying the aptamer at position G11 led to binding inhibition. Modification at G25, however, changed the selectivity towards theobromine (Kd ≈160 μm), with a poor affinity for theophylline (Kd >1.5 mm) being observed. Overall, 8-oxoG can have an impact on the structures of aptamers in a position-dependent manner, leading to altered target selectivity.
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Affiliation(s)
- Courtney Kiggins
- Present address: Department of ChemistryU.S. Air Force Academy2355 Fairchild DriveUSAF AcademyColorado SpringsCO80840USA
| | - Austin Skinner
- Department of ChemistryUniversity of Colorado Denver1151 Arapahoe Street, Science Building Room 4145DenverCO80204USA
| | - Marino J. E. Resendiz
- Department of ChemistryUniversity of Colorado Denver1151 Arapahoe Street, Science Building Room 4145DenverCO80204USA
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8
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Shcherbik N, Pestov DG. The Impact of Oxidative Stress on Ribosomes: From Injury to Regulation. Cells 2019; 8:cells8111379. [PMID: 31684095 PMCID: PMC6912279 DOI: 10.3390/cells8111379] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/23/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023] Open
Abstract
The ribosome is a complex ribonucleoprotein-based molecular machine that orchestrates protein synthesis in the cell. Both ribosomal RNA and ribosomal proteins can be chemically modified by reactive oxygen species, which may alter the ribosome′s functions or cause a complete loss of functionality. The oxidative damage that ribosomes accumulate during their lifespan in a cell may lead to reduced or faulty translation and contribute to various pathologies. However, remarkably little is known about the biological consequences of oxidative damage to the ribosome. Here, we provide a concise summary of the known types of changes induced by reactive oxygen species in rRNA and ribosomal proteins and discuss the existing experimental evidence of how these modifications may affect ribosome dynamics and function. We emphasize the special role that redox-active transition metals, such as iron, play in ribosome homeostasis and stability. We also discuss the hypothesis that redox-mediated ribosome modifications may contribute to adaptive cellular responses to stress.
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Affiliation(s)
- Natalia Shcherbik
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA.
| | - Dimitri G Pestov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA.
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9
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Thomas EN, Simms CL, Keedy HE, Zaher HS. Insights into the base-pairing preferences of 8-oxoguanosine on the ribosome. Nucleic Acids Res 2019; 47:9857-9870. [PMID: 31400119 PMCID: PMC6765139 DOI: 10.1093/nar/gkz701] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 02/06/2023] Open
Abstract
Of the four bases, guanine is the most susceptible to oxidation, which results in the formation of 8-oxoguanine (8-oxoG). In protein-free DNA, 8-oxodG adopts the syn conformation more frequently than the anti one. In the syn conformation, 8-oxodG base pairs with dA. The equilibrium between the anti and syn conformations of the adduct are known to be altered by the enzyme recognizing 8-oxodG. We previously showed that 8-oxoG in mRNA severely disrupts tRNA selection, but the underlying mechanism for these effects was not addressed. Here, we use miscoding antibiotics and ribosome mutants to probe how 8-oxoG interacts with the tRNA anticodon in the decoding center. Addition of antibiotics and introduction of error-inducing mutations partially suppressed the effects of 8-oxoG. Under these conditions, rates and/or endpoints of peptide-bond formation for the cognate (8-oxoG•C) and near-cognate (8-oxoG•A) aminoacyl-tRNAs increased. In contrast, the antibiotics had little effect on other mismatches, suggesting that the lesion restricts the nucleotide from forming other interactions. Our findings suggest that 8-oxoG predominantly adopts the syn conformation in the A site. However, its ability to base pair with adenosine in this conformation is not sufficient to promote the necessary structural changes for tRNA selection to proceed.
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Affiliation(s)
- Erica N Thomas
- Department of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO 63130, USA
| | - Carrie L Simms
- Department of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO 63130, USA
| | - Hannah E Keedy
- Department of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO 63130, USA
| | - Hani S Zaher
- Department of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO 63130, USA
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10
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Herbert C, Dzowo YK, Urban A, Kiggins CN, Resendiz MJE. Reactivity and Specificity of RNase T 1, RNase A, and RNase H toward Oligonucleotides of RNA Containing 8-Oxo-7,8-dihydroguanosine. Biochemistry 2018; 57:2971-2983. [PMID: 29683663 DOI: 10.1021/acs.biochem.8b00277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Understanding how oxidatively damaged RNA interacts with ribonucleases is important because of its proposed role in the development and progression of disease. Thus, understanding structural aspects of RNA containing lesions generated under oxidative stress, as well as its interactions with other biopolymers, is fundamental. We explored the reactivity of RNase A, RNase T1, and RNase H toward oligonucleotides of RNA containing 8-oxo-7,8-dihydroguanosine (8oxoG). This is the first example that addresses this relationship and will be useful for understanding (1) how these RNases can be used to characterize the structural impact that this lesion has on RNA and (2) how oxidatively modified RNA may be handled intracellularly. 8-OxoG was incorporated into 10-16-mers of RNA, and its reactivity with each ribonuclease was assessed via electrophoretic analyses, circular dichroism, and the use of other C8-purine-modified analogues (8-bromoguanosine, 8-methoxyguanosine, and 8-oxoadenosine). RNase T1 does not recognize sites containing 8-oxoG, while RNase A recognizes and cleaves RNA at positions containing this lesion while differentiating if it is involved in H-bonding. The selectivity of RNase A followed the order C > 8-oxoG ≈ U. In addition, isothermal titration calorimetry showed that an 8-oxoG-C3'-methylphosphate derivative can inhibit RNase A activity. Cleavage patterns obtained from RNase H displayed changes in reactivity in a sequence- and concentration-dependent manner and displayed recognition at sites containing the modification in some cases. These data will aid in understanding how this modification affects reactivity with ribonucleases and will enable the characterization of global and local structural changes in oxidatively damaged RNA.
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Affiliation(s)
- Cassandra Herbert
- Department of Chemistry , University of Colorado Denver , Science Building, 1151 Arapahoe Street , Denver , Colorado 80204 , United States
| | - Yannick Kokouvi Dzowo
- Department of Chemistry , University of Colorado Denver , Science Building, 1151 Arapahoe Street , Denver , Colorado 80204 , United States
| | - Anthony Urban
- Department of Chemistry , University of Colorado Denver , Science Building, 1151 Arapahoe Street , Denver , Colorado 80204 , United States
| | - Courtney N Kiggins
- Department of Chemistry , University of Colorado Denver , Science Building, 1151 Arapahoe Street , Denver , Colorado 80204 , United States
| | - Marino J E Resendiz
- Department of Chemistry , University of Colorado Denver , Science Building, 1151 Arapahoe Street , Denver , Colorado 80204 , United States
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11
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Francis AJ, Resendiz MJE. Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism. J Vis Exp 2017. [PMID: 28784951 DOI: 10.3791/56189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5'-[CUA CGG AAU CAU]-3' containing zero, one, or two modifications located at the C2'-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2'-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in 2013) that uses phosphoramidite chemistry.
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