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Luige J, Armaos A, Tartaglia GG, Ørom UAV. Predicting nuclear G-quadruplex RNA-binding proteins with roles in transcription and phase separation. Nat Commun 2024; 15:2585. [PMID: 38519458 PMCID: PMC10959947 DOI: 10.1038/s41467-024-46731-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 03/08/2024] [Indexed: 03/25/2024] Open
Abstract
RNA-binding proteins are central for many biological processes and their characterization has demonstrated a broad range of functions as well as a wide spectrum of target structures. RNA G-quadruplexes are important regulatory elements occurring in both coding and non-coding transcripts, yet our knowledge of their structure-based interactions is at present limited. Here, using theoretical predictions and experimental approaches, we show that many chromatin-binding proteins bind to RNA G-quadruplexes, and we classify them based on their RNA G-quadruplex-binding potential. Combining experimental identification of nuclear RNA G-quadruplex-binding proteins with computational approaches, we build a prediction tool that assigns probability score for a nuclear protein to bind RNA G-quadruplexes. We show that predicted G-quadruplex RNA-binding proteins exhibit a high degree of protein disorder and hydrophilicity and suggest involvement in both transcription and phase-separation into membrane-less organelles. Finally, we present the G4-Folded/UNfolded Nuclear Interaction Explorer System (G4-FUNNIES) for estimating RNA G4-binding propensities at http://service.tartaglialab.com/new_submission/G4FUNNIES .
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Affiliation(s)
- Johanna Luige
- RNA Biology and Innovation, Institute of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Alexandros Armaos
- Centre for Human Technologies (CHT), Istituto Italiano di Tecnologia (IIT), Via Enrico Melen, 83, 16152, Genova, Italy
| | - Gian Gaetano Tartaglia
- Centre for Human Technologies (CHT), Istituto Italiano di Tecnologia (IIT), Via Enrico Melen, 83, 16152, Genova, Italy.
- Catalan Institution for Research and Advanced Studies ICREA Passeig Lluis Companys, 23 08010, Barcelona, Spain.
| | - Ulf Andersson Vang Ørom
- RNA Biology and Innovation, Institute of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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2
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Majumder P, Shukla C, Arya A, Sharma S, Datta B. G-quadruplexes in MTOR and induction of autophagy. Sci Rep 2024; 14:2525. [PMID: 38291093 PMCID: PMC10827794 DOI: 10.1038/s41598-024-52561-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/20/2024] [Indexed: 02/01/2024] Open
Abstract
G-quadruplex (G4) structures have emerged as singular therapeutic targets for cancer and neurodegeneration. Autophagy, a crucial homeostatic mechanism of the cell, is often dysregulated in neurodegenerative diseases and cancers. We used QGRS mapper to identify 470 G4 sequences in MTOR, a key negative regulator of autophagy. We sought to identify a functional context by leveraging the effect of G4-targeting ligands on MTOR G4 sequences. The effect of Bis-4,3, a G4 selective dimeric carbocyanine dye, was compared with the known G4-stabilizing activity of the porphyrin, TMPyP4 in HeLa and SHSY-5Y cells. Our results show that treatment with G4-selective ligands downregulates MTOR RNA and mTOR protein expression levels. This is the first report describing G4 motifs in MTOR. This study indicates a possible role of G4 stabilizing ligands in induction of autophagy by downregulation of mTOR levels, albeit not precluding MTOR independent pathways.
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Affiliation(s)
- Piyali Majumder
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India
| | - Chinmayee Shukla
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India
| | - Arjun Arya
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India
| | - Shubham Sharma
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India
| | - Bhaskar Datta
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India.
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India.
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3
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Sahayasheela VJ, Sugiyama H. RNA G-quadruplex in functional regulation of noncoding RNA: Challenges and emerging opportunities. Cell Chem Biol 2024; 31:53-70. [PMID: 37909035 DOI: 10.1016/j.chembiol.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/12/2023] [Accepted: 08/22/2023] [Indexed: 11/02/2023]
Abstract
G-quadruplexes (G4s) are stable, noncanonical structures formed in guanine (G)-rich sequences of DNA/RNA. G4 structures are reported to play a regulatory role in various cellular processes and, recently, a considerable number of studies have attributed new biological functions to these structures, especially in RNA. Noncoding RNA (ncRNA), which does not translate into a functional protein, is widely expressed and has been shown to play a key role in shaping cellular activity. There has been growing evidence of G4 formation in several ncRNA classes, and it has been identified as a key part for diverse biological functions and physio-pathological contexts in neurodegenerative diseases and cancer. This review discusses RNA G4s (rG4s) in ncRNA, focusing on the molecular mechanism underlying its function. This review also aims to highlight potential and emerging opportunities to identify and target the rG4s in ncRNA to understand its function and, ultimately, treat many diseases.
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Affiliation(s)
- Vinodh J Sahayasheela
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-Ushinomaecho, Sakyo-Ku, Kyoto 606-8501, Japan.
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4
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Jansson-Fritzberg LI, Sousa CI, Smallegan MJ, Song JJ, Gooding AR, Kasinath V, Rinn JL, Cech TR. DNMT1 inhibition by pUG-fold quadruplex RNA. RNA 2023; 29:346-360. [PMID: 36574982 PMCID: PMC9945446 DOI: 10.1261/rna.079479.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Aberrant DNA methylation is one of the earliest hallmarks of cancer. DNMT1 is responsible for methylating newly replicated DNA, but the precise regulation of DNMT1 to ensure faithful DNA methylation remains poorly understood. A link between RNA and chromatin-associated proteins has recently emerged, and several studies have shown that DNMT1 can be regulated by a variety of RNAs. In this study, we have confirmed that human DNMT1 indeed interacts with multiple RNAs, including its own nuclear mRNA. Unexpectedly, we found that DNMT1 exhibits a strong and specific affinity for GU-rich RNAs that form a pUG-fold, a noncanonical G-quadruplex. We find that pUG-fold-capable RNAs inhibit DNMT1 activity by inhibiting binding of hemimethylated DNA, and we additionally provide evidence for multiple RNA binding modes with DNMT1. Together, our data indicate that a human chromatin-associated protein binds to and is regulated by pUG-fold RNA.
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Affiliation(s)
- Linnea I Jansson-Fritzberg
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Camila I Sousa
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Michael J Smallegan
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Jessica J Song
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Anne R Gooding
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Vignesh Kasinath
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - John L Rinn
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Thomas R Cech
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
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Sahayasheela VJ, Yu Z, Hidaka T, Pandian GN, Sugiyama H. Mitochondria and G-quadruplex evolution: an intertwined relationship. Trends Genet 2023; 39:15-30. [PMID: 36414480 PMCID: PMC9772288 DOI: 10.1016/j.tig.2022.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/27/2022] [Accepted: 10/27/2022] [Indexed: 11/21/2022]
Abstract
G-quadruplexes (G4s) are non-canonical structures formed in guanine (G)-rich sequences through stacked G tetrads by Hoogsteen hydrogen bonding. Several studies have demonstrated the existence of G4s in the genome of various organisms, including humans, and have proposed that G4s have a regulatory role in various cellular functions. However, little is known regarding the dissemination of G4s in mitochondria. In this review, we report the observation that the number of potential G4-forming sequences in the mitochondrial genome increases with the evolutionary complexity of different species, suggesting that G4s have a beneficial role in higher-order organisms. We also discuss the possible function of G4s in mitochondrial (mt)DNA and long noncoding (lnc)RNA and their role in various biological processes.
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Affiliation(s)
- Vinodh J Sahayasheela
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Zutao Yu
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Takuya Hidaka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Ganesh N Pandian
- Institute for Integrated Cell-Material Science (WPI-iCeMS), Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan; Institute for Integrated Cell-Material Science (WPI-iCeMS), Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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6
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Savva L, Fossépré M, Keramidas O, Themistokleous A, Rizeq N, Panagiotou N, Leclercq M, Nicolaidou E, Surin M, Hayes SC, Georgiades SN. Gaining Insights on the Interactions of a Class of Decorated (2-([2,2'-Bipyridin]-6-yl)phenyl)platinum Compounds with c-Myc Oncogene Promoter G-Quadruplex and Other DNA Structures. Chemistry 2022; 28:e202201497. [PMID: 35726630 PMCID: PMC9804160 DOI: 10.1002/chem.202201497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Indexed: 01/05/2023]
Abstract
Organometallic molecules offer some of the most promising scaffolds for interaction with G-quadruplex nucleic acids. We report the efficient synthesis of a family of organoplatinum(II) complexes, featuring a 2-([2,2'-bipyridin]-6-yl)phenyl tridentate (N∧ N∧ C) ligand, that incorporates peripheral side-chains aiming at enhancing and diversifying its interaction capabilities. These include a di-isopropyl carbamoyl amide, a morpholine ethylenamide, two enantiomeric proline imides and an oxazole. The binding affinities of the Pt-complexes were evaluated via UV-vis and fluorescence titrations, against 5 topologically-distinct DNA structures, including c-myc G-quadruplex, two telomeric (22AG) G-quadruplexes, a duplex (ds26) and a single-stranded (polyT) DNA. All compounds exhibited binding selectivity in favour of c-myc, with association constants (Ka ) in the range of 2-5×105 M-1 , lower affinity for both folds of 22AG and for ds26 and negligible affinity for polyT. Remarkable emission enhancements (up to 200-fold) upon addition of excess DNA were demonstrated by a subset of the compounds with c-myc, providing a basis for optical selectivity, since optical response to all other tested DNAs was low. A c-myc DNA-melting experiment showed significant stabilizing abilities for all compounds, with the most potent binder, the morpholine-Pt-complex, exhibiting a ΔTm >30 °C, at 1 : 5 DNA-to-ligand molar ratio. The same study implied contributions of the diverse side-chains to helix stabilization. To gain direct evidence of the nature of the interactions, mixtures of c-myc with the four most promising compounds were studied via UV Resonance Raman (UVRR) spectroscopy, which revealed end-stacking binding mode, combined with interactions of side-chains with loop nucleobase residues. Docking simulations were conducted to provide insights into the binding modes for the same four Pt-compounds, suggesting that the binding preference for two alternative orientations of the c-myc G-quadruplex thymine 'cap' ('open' vs. 'closed'), as well as the relative contributions to affinity from end-stacking and H-bonding, are highly dependent on the nature of the interacting Pt-complex side-chain.
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Affiliation(s)
- Loukiani Savva
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
| | - Mathieu Fossépré
- Laboratory for Chemistry of Novel MaterialsUniversity of Mons – UMONS20 Place du ParcB-7000MonsBelgium
| | - Odysseas Keramidas
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
| | | | - Natalia Rizeq
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
| | - Nikos Panagiotou
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
| | - Maxime Leclercq
- Laboratory for Chemistry of Novel MaterialsUniversity of Mons – UMONS20 Place du ParcB-7000MonsBelgium
| | - Eliana Nicolaidou
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
| | - Mathieu Surin
- Laboratory for Chemistry of Novel MaterialsUniversity of Mons – UMONS20 Place du ParcB-7000MonsBelgium
| | - Sophia C. Hayes
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
| | - Savvas N. Georgiades
- Department of ChemistryUniversity of Cyprus1 Panepistimiou Avenue, Aglandjia2109NicosiaCyprus
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Chen X, Xue G, Zhao J, Zhang Y, Zhang S, Wang W, Li Y, Yuan J, He L, Chan CY, Liu Y, Chen W, Zhao Y, Hu P, Sun H, Kwok CK, Wang H. Lockd promotes myoblast proliferation and muscle regeneration via binding with DHX36 to facilitate 5' UTR rG4 unwinding and Anp32e translation. Cell Rep 2022; 39:110927. [PMID: 35675771 DOI: 10.1016/j.celrep.2022.110927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/10/2022] [Accepted: 05/18/2022] [Indexed: 11/20/2022] Open
Abstract
Adult muscle stem cells, also known as satellite cells (SCs), play pivotal roles in muscle regeneration, and long non-coding RNA (lncRNA) functions in SCs remain largely unknown. Here, we identify a lncRNA, Lockd, which is induced in activated SCs upon acute muscle injury. We demonstrate that Lockd promotes SC proliferation; deletion of Lockd leads to cell-cycle arrest, and in vivo repression of Lockd in mouse muscles hinders regeneration process. Mechanistically, we show that Lockd directly interacts with RNA helicase DHX36 and the 5'end of Lockd possesses the strongest binding with DHX36. Furthermore, we demonstrate that Lockd stabilizes the interaction between DHX36 and EIF3B proteins; synergistically, this complex unwinds the RNA G-quadruplex (rG4) structure formed at Anp32e mRNA 5' UTR and promotes the translation of ANP32E protein, which is required for myoblast proliferation. Altogether, our findings identify a regulatory Lockd/DHX36/Anp32e axis that promotes myoblast proliferation and acute-injury-induced muscle regeneration.
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Georgakopoulos-Soares I, Parada GE, Hemberg M. Secondary structures in RNA synthesis, splicing and translation. Comput Struct Biotechnol J 2022; 20:2871-2884. [PMID: 35765654 PMCID: PMC9198270 DOI: 10.1016/j.csbj.2022.05.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/30/2022] Open
Abstract
Even though the functional role of mRNA molecules is primarily decided by the nucleotide sequence, several properties are determined by secondary structure conformations. Examples of secondary structures include long range interactions, hairpins, R-loops and G-quadruplexes and they are formed through interactions of non-adjacent nucleotides. Here, we discuss advances in our understanding of how secondary structures can impact RNA synthesis, splicing, translation and mRNA half-life. During RNA synthesis, secondary structures determine RNA polymerase II (RNAPII) speed, thereby influencing splicing. Splicing is also determined by RNA binding proteins and their binding rates are modulated by secondary structures. For the initiation of translation, secondary structures can control the choice of translation start site. Here, we highlight the mechanisms by which secondary structures modulate these processes, discuss advances in technologies to detect and study them systematically, and consider the roles of RNA secondary structures in disease.
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Teng X, Dai Y, Li J. Methodological advances of bioanalysis and biochemical targeting of intracellular G-quadruplexes. Exploration (Beijing) 2022; 2:20210214. [PMID: 37323879 PMCID: PMC10191030 DOI: 10.1002/exp.20210214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 01/11/2022] [Indexed: 06/17/2023]
Abstract
G-quadruplexes (G4s) are a kind of non-canonical nucleic acid secondary structures, which involve in various biological processes in living cells. The relationships between G4s and human diseases, such as tumors, neurodegenerative diseases, and viral infections, have attracted great attention in the last decade. G4s are considered as a promising new target for disease treatment. For instance, G4 ligands are reported to be potentially effective in SARS-COV-2 treatment. However, because of the lack of analytical methods with high performance for the identification of intracellular G4s, the detailed mechanisms of the biofunctions of G4s remain elusive. Meanwhile, through demonstrating the principles of how the G4s systematically modulate the cellular processes with advanced detection methods, biochemical targeting of G4s in living cells can be realized by chemical and biological tools and becomes useful in biomedicine. This review highlights recent methodological advances about intracellular G4s and provides an outlook on the improvement of the bioanalysis and biochemical targeting tools of G4s.
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Affiliation(s)
- Xucong Teng
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical BiologyTsinghua UniversityBeijingChina
| | - Yicong Dai
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical BiologyTsinghua UniversityBeijingChina
| | - Jinghong Li
- Department of Chemistry, Center for BioAnalytical Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical BiologyTsinghua UniversityBeijingChina
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Pawłowska M, Kulesza J, Augustin E. c-Myc Protein Level Affected by Unsymmetrical Bisacridines Influences Apoptosis and Senescence Induced in HCT116 Colorectal and H460 Lung Cancer Cells. Int J Mol Sci 2022; 23:3061. [PMID: 35328482 DOI: 10.3390/ijms23063061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/01/2022] [Accepted: 03/10/2022] [Indexed: 12/04/2022] Open
Abstract
Unsymmetrical bisacridines (UAs) are highly active antitumor compounds. They contain in their structure the drugs previously synthesized in our Department: C-1311 and C-1748. UAs exhibit different properties than their monomer components. They do not intercalate to dsDNA but stabilize the G-quadruplex structures, particularly those of the MYC and KRAS genes. Since MYC and KRAS are often mutated and constitutively expressed in cancer cells, they can be used as therapeutic targets. Herein, we investigate whether UAs can affect the expression and protein level of c-Myc and K-Ras in HCT116 and H460 cancer cells, and if so, what are the consequences for the UAs-induced cellular response. UAs did not affect K-Ras, but they strongly influenced the expression and translation of the c-Myc protein, and in H460 cells, they caused its full inhibition. UAs treatment resulted in apoptosis, as confirmed by the morphological changes, the presence of sub-G1 population and active caspase-3, cleaved PARP, annexin-V/PI staining and a decrease in mitochondrial potential. Importantly, apoptosis was induced earlier and to a greater extent in H460 compared to HCT116 cells. Moreover, accelerated senescence occurred only in H460 cells. In conclusion, the strong inhibition of c-Myc by UAs in H460 cells may participate in the final cellular response (apoptosis, senescence).
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Hoque ME, Mahendran T, Basu S. Reversal of G-Quadruplexes’ Role in Translation Control When Present in the Context of an IRES. Biomolecules 2022; 12:314. [PMID: 35204814 PMCID: PMC8869680 DOI: 10.3390/biom12020314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 02/01/2023] Open
Abstract
G-quadruplexes (GQs) are secondary nucleic acid structures that play regulatory roles in various cellular processes. G-quadruplex-forming sequences present within the 5′ UTR of mRNAs can function not only as repressors of translation but also as elements required for optimum function. Based upon previous reports, the majority of the 5′ UTR GQ structures inhibit translation, presumably by blocking the ribosome scanning process that is essential for detection of the initiation codon. However, there are certain mRNAs containing GQs that have been identified as positive regulators of translation, as they are needed for translation initiation. While most cellular mRNAs utilize the 5′ cap structure to undergo cap-dependent translation initiation, many rely on cap-independent translation under certain conditions in which the cap-dependent initiation mechanism is not viable or slowed down, for example, during development, under stress and in many diseases. Cap-independent translation mainly occurs via Internal Ribosomal Entry Sites (IRESs) that are located in the 5′ UTR of mRNAs and are equipped with structural features that can recruit the ribosome or other factors to initiate translation without the need for a 5′ cap. In this review, we will focus only on the role of RNA GQs present in the 5′ UTR of mRNAs, where they play a critical role in translation initiation, and discuss the potential mechanism of this phenomenon, which is yet to be fully delineated.
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Dai Y, Teng X, Li J. Single‐Cell Visualization of Monogenic RNA G‐quadruplex and Occupied G‐quadruplex Ratio through a Module‐Assembled Multifunctional Probes Assay (MAMPA). Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yicong Dai
- Department of Chemistry Center for BioAnalytical Chemistry Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology Tsinghua University Beijing 100084 China
| | - Xucong Teng
- Department of Chemistry Center for BioAnalytical Chemistry Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology Tsinghua University Beijing 100084 China
| | - Jinghong Li
- Department of Chemistry Center for BioAnalytical Chemistry Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology Tsinghua University Beijing 100084 China
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Niu K, Zhang X, Song Q, Feng Q. G-Quadruplex Regulation of VEGFA mRNA Translation by RBM4. Int J Mol Sci 2022; 23:ijms23020743. [PMID: 35054929 PMCID: PMC8776124 DOI: 10.3390/ijms23020743] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 02/01/2023] Open
Abstract
In eukaryotes, mRNAs translation is mainly mediated in a cap-dependent or cap-independent manner. The latter is primarily initiated at the internal ribosome entry site (IRES) in the 5'-UTR of mRNAs. It has been reported that the G-quadruplex structure (G4) in the IRES elements could regulate the IRES activity. We previously confirmed RBM4 (also known as LARK) as a G4-binding protein in human. In this study, to investigate whether RBM4 is involved in the regulation of the IRES activity by binding with the G4 structure within the IRES element, the IRES-A element in the 5'-UTR of vascular endothelial growth factor A (VEGFA) was constructed into a dicistronic reporter vector, psiCHECK2, and the effect of RBM4 on the IRES activity was tested in 293T cells. The results showed that the IRES insertion significantly increased the FLuc expression activity, indicating that this G4-containing IRES was active in 293T cells. When the G4 structure in the IRES was disrupted by base mutation, the IRES activity was significantly decreased. The IRES activity was notably increased when the cells were treated with G4 stabilizer PDS. EMSA results showed that RBM4 specifically bound the G4 structure in the IRES element. The knockdown of RBM4 substantially reduced the IRES activity, whereas over-expressing RBM4 increased the IRES activity. Taking all results together, we demonstrated that RBM4 promoted the mRNA translation of VEGFA gene by binding to the G4 structure in the IRES.
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Affiliation(s)
- Kangkang Niu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (K.N.); (X.Z.)
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Xiaojuan Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (K.N.); (X.Z.)
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Qisheng Song
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA;
| | - Qili Feng
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (K.N.); (X.Z.)
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
- Correspondence:
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14
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Mou X, Liew SW, Kwok CK. Identification and targeting of G-quadruplex structures in MALAT1 long non-coding RNA. Nucleic Acids Res 2022; 50:397-410. [PMID: 34904666 PMCID: PMC8754639 DOI: 10.1093/nar/gkab1208] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/07/2021] [Accepted: 11/24/2021] [Indexed: 12/11/2022] Open
Abstract
RNA G-quadruplexes (rG4s) have functional roles in many cellular processes in diverse organisms. While a number of rG4 examples have been reported in coding messenger RNAs (mRNA), so far only limited works have studied rG4s in non-coding RNAs (ncRNAs), especially in long non-coding RNAs (lncRNAs) that are of emerging interest and significance in biology. Herein, we report that MALAT1 lncRNA contains conserved rG4 motifs, forming thermostable rG4 structures with parallel topology. We also show that rG4s in MALAT1 lncRNA can interact with NONO protein with high specificity and affinity in vitro and in nuclear cell lysate, and we provide cellular data to support that NONO protein recognizes MALAT1 lncRNA via rG4 motifs. Notably, we demonstrate that rG4s in MALAT1 lncRNA can be targeted by the rG4-specific small molecule, peptide, and L-aptamer, leading to the dissociation of MALAT1 rG4-NONO protein interaction. Altogether, this study uncovers new and important rG4s in MALAT1 lncRNAs, reveals their specific interactions with NONO protein, offers multiple strategies for targeting MALAT1 and its RNA-protein complex via its rG4 structure and illustrates the prevalence and significance of rG4s in ncRNAs.
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Affiliation(s)
- Xi Mou
- Department of Chemistry and State Key Laboratory of Marine Pollution, City
University of Hong Kong, Kowloon Tong, Hong Kong
SAR, China
| | - Shiau Wei Liew
- Department of Chemistry and State Key Laboratory of Marine Pollution, City
University of Hong Kong, Kowloon Tong, Hong Kong
SAR, China
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City
University of Hong Kong, Kowloon Tong, Hong Kong
SAR, China
- Shenzhen Research Institute of City University of Hong Kong,
Shenzhen, China
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15
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Smirnova VV, Shestakova ED, Nogina DS, Mishchenko PA, Prikazchikova TA, Zatsepin TS, Kulakovskiy IV, Shatsky IN, Terenin IM. Ribosomal leaky scanning through a translated uORF requires eIF4G2. Nucleic Acids Res 2022; 50:1111-1127. [PMID: 35018467 PMCID: PMC8789081 DOI: 10.1093/nar/gkab1286] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 12/07/2021] [Accepted: 12/18/2021] [Indexed: 11/21/2022] Open
Abstract
eIF4G2 (DAP5 or Nat1) is a homologue of the canonical translation initiation factor eIF4G1 in higher eukaryotes but its function remains poorly understood. Unlike eIF4G1, eIF4G2 does not interact with the cap-binding protein eIF4E and is believed to drive translation under stress when eIF4E activity is impaired. Here, we show that eIF4G2 operates under normal conditions as well and promotes scanning downstream of the eIF4G1-mediated 40S recruitment and cap-proximal scanning. Specifically, eIF4G2 facilitates leaky scanning for a subset of mRNAs. Apparently, eIF4G2 replaces eIF4G1 during scanning of 5′ UTR and the necessity for eIF4G2 only arises when eIF4G1 dissociates from the scanning complex. In particular, this event can occur when the leaky scanning complexes interfere with initiating or elongating 80S ribosomes within a translated uORF. This mechanism is therefore crucial for higher eukaryotes which are known to have long 5′ UTRs with highly frequent uORFs. We suggest that uORFs are not the only obstacle on the way of scanning complexes towards the main start codon, because certain eIF4G2 mRNA targets lack uORF(s). Thus, higher eukaryotes possess two distinct scanning complexes: the principal one that binds mRNA and initiates scanning, and the accessory one that rescues scanning when the former fails.
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Affiliation(s)
- Victoria V Smirnova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Ekaterina D Shestakova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Daria S Nogina
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Polina A Mishchenko
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | | | - Timofei S Zatsepin
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow 121205, Russia.,Chemistry Department, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ivan V Kulakovskiy
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia.,Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia.,Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow 119991, Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia.,Sirius University of Science and Technology, Sochi, Olimpiyskiy ave. b.1, 354349, Russia
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16
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Varshney D, Cuesta SM, Herdy B, Abdullah UB, Tannahill D, Balasubramanian S. RNA G-quadruplex structures control ribosomal protein production. Sci Rep 2021; 11:22735. [PMID: 34815422 PMCID: PMC8611094 DOI: 10.1038/s41598-021-01847-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/27/2021] [Indexed: 12/13/2022] Open
Abstract
Four-stranded G-quadruplex (G4) structures form from guanine-rich tracts, but the extent of their formation in cellular RNA and details of their role in RNA biology remain poorly defined. Herein, we first delineate the presence of endogenous RNA G4s in the human cytoplasmic transcriptome via the binding sites of G4-interacting proteins, DDX3X (previously published), DHX36 and GRSF1. We demonstrate that a sub-population of these RNA G4s are reliably detected as folded structures in cross-linked cellular lysates using the G4 structure-specific antibody BG4. The 5' UTRs of protein coding mRNAs show significant enrichment in folded RNA G4s, particularly those for ribosomal proteins. Mutational disruption of G4s in ribosomal protein UTRs alleviates translation in vitro, whereas in cells, depletion of G4-resolving helicases or treatment with G4-stabilising small molecules inhibit the translation of ribosomal protein mRNAs. Our findings point to a common mode for translational co-regulation mediated by G4 structures. The results reveal a potential avenue for therapeutic intervention in diseases with dysregulated translation, such as cancer.
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Affiliation(s)
- Dhaval Varshney
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Sergio Martinez Cuesta
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
- Data Sciences and Quantitative Biology, Discovery Sciences, AstraZeneca, Cambridge, UK
| | - Barbara Herdy
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Ummi Binti Abdullah
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - David Tannahill
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Shankar Balasubramanian
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
- School of Clinical Medicine, University of Cambridge, Cambridge, CB2 0SP, UK.
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17
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Dai Y, Teng X, Li J. Single-cell Visualization of Monogenic RNA G-quadruplex and Occupied G-quadruplex Ratio through Module Assembled Multifunctional Probes Assay (MAMPA). Angew Chem Int Ed Engl 2021; 61:e202111132. [PMID: 34773681 DOI: 10.1002/anie.202111132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/24/2021] [Indexed: 11/12/2022]
Abstract
G-quadruplexes (G4s), non-canonical nucleic acid secondary structure, regulate many biological functions and are considered as potential molecular targets for therapeutics of cancers. However, due to the lack of analytical methods, the regulating mechanism of monogenic G4s is still unclear. Here, we developed a Module Assembled Multifunctional Probes Assay (MAMPA) for visualizing endogenous G4s in individual genes in single cells. Two modular probes separately recognize G4 structures and the adjacent RNA sequences, and the module assembly enables imaging of G4s in an individual RNA with high specificity. Through imaging G4s in several individual genes, we found that G4s were steadily occupied by G4 Binding Proteins (G4BPs) in various mRNAs in every cell line and defined "Occupied G4 Ratio". In all, we demonstrated MAMPA was suitable for most experiment situations and found that Occupied G4 Ratios had the potential to become a new parameter for the study of G4s in living cells.
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Affiliation(s)
- Yicong Dai
- Tsinghua University, Department of Chemistry, 100084, CHINA
| | - Xucong Teng
- Tsinghua University, Department of Chemistry, CHINA
| | - Jinghong Li
- Tsinghua University, Department of Chemistry, Haidian Street, Beijing, CHINA
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18
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Marzano S, Pagano B, Iaccarino N, Di Porzio A, De Tito S, Vertecchi E, Salvati E, Randazzo A, Amato J. Targeting of Telomeric Repeat-Containing RNA G-Quadruplexes: From Screening to Biophysical and Biological Characterization of a New Hit Compound. Int J Mol Sci 2021; 22:10315. [PMID: 34638655 DOI: 10.3390/ijms221910315] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/10/2021] [Accepted: 09/22/2021] [Indexed: 12/19/2022] Open
Abstract
DNA G-quadruplex (G4) structures, either within gene promoter sequences or at telomeres, have been extensively investigated as potential small-molecule therapeutic targets. However, although G4s forming at the telomeric DNA have been extensively investigated as anticancer targets, few studies focus on the telomeric repeat-containing RNA (TERRA), transcribed from telomeres, as potential pharmacological targets. Here, a virtual screening approach to identify a library of drug-like putative TERRA G4 binders, in tandem with circular dichroism melting assay to study their TERRA G4-stabilizing properties, led to the identification of a new hit compound. The affinity of this compound for TERRA RNA and some DNA G4s was analyzed through several biophysical techniques and its biological activity investigated in terms of antiproliferative effect, DNA damage response (DDR) activation, and TERRA RNA expression in high vs. low TERRA-expressing human cancer cells. The selected hit showed good affinity for TERRA G4 and no binding to double-stranded DNA. In addition, biological assays showed that this compound is endowed with a preferential cytotoxic effect on high TERRA-expressing cells, where it induces a DDR at telomeres, probably by displacing TERRA from telomeres. Our studies demonstrate that the identification of TERRA G4-targeting drugs with potential pharmacological effects is achievable, shedding light on new perspectives aimed at discovering new anticancer agents targeting these G4 structures.
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19
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Abstract
Methodological progresses and piling evidence prove the rG4 biology in vivo. rG4s step in virtually every aspect of RNA biology. Helicases unwinding of rG4s is a fine regulatory layer to the downstream processes and general cell homeostasis. The current knowledge is however limited to a few cell lines. The regulation of helicases themselves is delineating as a important question. Non-helicase rG4-processing proteins likely play a role.
The nucleic acid structure called G-quadruplex (G4) is currently discussed to function in nucleic acid-based mechanisms that influence several cellular processes. They can modulate the cellular machinery either positively or negatively, both at the DNA and RNA level. The majority of what we know about G4 biology comes from DNA G4 (dG4) research. RNA G4s (rG4), on the other hand, are gaining interest as researchers become more aware of their role in several aspects of cellular homeostasis. In either case, the correct regulation of G4 structures within cells is essential and demands specialized proteins able to resolve them. Small changes in the formation and unfolding of G4 structures can have severe consequences for the cells that could even stimulate genome instability, apoptosis or proliferation. Helicases are the most relevant negative G4 regulators, which prevent and unfold G4 formation within cells during different pathways. Yet, and despite their importance only a handful of rG4 unwinding helicases have been identified and characterized thus far. This review addresses the current knowledge on rG4s-processing helicases with a focus on methodological approaches. An example of a non-helicase rG4s-unwinding protein is also briefly described.
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Affiliation(s)
- Marco Caterino
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, 53127 Bonn, Germany
| | - Katrin Paeschke
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, 53127 Bonn, Germany.
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20
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Zhang R, Liu Y, Zhang X, Xiao K, Hou Y, Liu H, Sun X. Detecting and Profiling Endogenous RNA G-Quadruplexes in the Human Transcriptome. Int J Mol Sci 2021; 22:ijms22158012. [PMID: 34360778 PMCID: PMC8347560 DOI: 10.3390/ijms22158012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 12/24/2022] Open
Abstract
G-quadruplexes are the non-canonical nucleic acid structures that are preferentially formed in G-rich regions. This structure has been shown to be associated with many biological functions. Regardless of the broad efforts on DNA G-quadruplexes, we still have limited knowledge on RNA G-quadruplexes, especially in a transcriptome-wide manner. Herein, by integrating the DMS-seq and the bioinformatics pipeline, we profiled and depicted the RNA G-quadruplexes in the human transcriptome. The genes that contain RNA G-quadruplexes in their specific regions are significantly related to immune pathways and the COVID-19-related gene sets. Bioinformatics analysis reveals the potential regulatory functions of G-quadruplexes on miRNA targeting at the scale of the whole transcriptome. In addition, the G-quadruplexes are depleted in the putative, not the real, PAS-strong poly(A) sites, which may weaken the possibility of such sites being the real cleaved sites. In brief, our study provides insight into the potential function of RNA G-quadruplexes in post-transcription.
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Affiliation(s)
- Rongxin Zhang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
| | - Yajun Liu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
- Hangzhou Hongquan Internet of Things Technology Co., Ltd., Hangzhou 310012, China
| | - Xingxing Zhang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
| | - Ke Xiao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
| | - Yue Hou
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
| | - Hongde Liu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
| | - Xiao Sun
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; (R.Z.); (Y.L.); (X.Z.); (K.X.); (Y.H.); (H.L.)
- Correspondence:
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21
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Qi T, Xu Y, Zhou T, Gu W. The Evolution of G-quadruplex Structure in mRNA Untranslated Region. Evol Bioinform Online 2021; 17:11769343211035140. [PMID: 34366661 DOI: 10.1177/11769343211035140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/06/2021] [Indexed: 01/22/2023] Open
Abstract
The RNA G-quadruplex (rG4) is a kind of non-canonical high-order secondary structure with important biological functions and is enriched in untranslated regions (UTRs) of protein-coding genes. However, how rG4 structures evolve is largely unknown. Here, we systematically investigated the evolution of RNA sequences around UTR rG4 structures in 5 eukaryotic organisms. We found universal selection on UTR sequences, which facilitated rG4 formation in all the organisms that we analyzed. While G-rich sequences were preferred in the rG4 structural region, C-rich sequences were selectively not preferred. The selective pressure acting on rG4 structures in the UTRs of genes with higher G content was significantly smaller. Furthermore, we found that rG4 structures experienced smaller evolutionary selection near the translation initiation region in the 5' UTR, near the polyadenylation signals in the 3' UTR, and in regions flanking the miRNA targets in the 3' UTR. These results suggest universal selection for rG4 formation in the UTRs of eukaryotic genomes and the selection may be related to the biological functions of rG4s.
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Affiliation(s)
- Ting Qi
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Yuming Xu
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Tong Zhou
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Wanjun Gu
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China.,Collaborative Innovation Center of Jiangsu Province of Cancer Prevention and Treatment of Chinese Medicine, Nanjing, Jiangsu, China.,School of Artificial Intelligence and Information Technology, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
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22
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Tateishi-Karimata H, Sugimoto N. Roles of non-canonical structures of nucleic acids in cancer and neurodegenerative diseases. Nucleic Acids Res 2021; 49:7839-7855. [PMID: 34244785 PMCID: PMC8373145 DOI: 10.1093/nar/gkab580] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 06/17/2021] [Accepted: 07/06/2021] [Indexed: 12/14/2022] Open
Abstract
Cancer and neurodegenerative diseases are caused by genetic and environmental factors. Expression of tumour suppressor genes is suppressed by mutations or epigenetic silencing, whereas for neurodegenerative disease-related genes, nucleic acid-based effects may be presented through loss of protein function due to erroneous protein sequences or gain of toxic function from extended repeat transcripts or toxic peptide production. These diseases are triggered by damaged genes and proteins due to lifestyle and exposure to radiation. Recent studies have indicated that transient, non-canonical structural changes in nucleic acids in response to the environment can regulate the expression of disease-related genes. Non-canonical structures are involved in many cellular functions, such as regulation of gene expression through transcription and translation, epigenetic regulation of chromatin, and DNA recombination. Transcripts generated from repeat sequences of neurodegenerative disease-related genes form non-canonical structures that are involved in protein transport and toxic aggregate formation. Intracellular phase separation promotes transcription and protein assembly, which are controlled by the nucleic acid structure and can influence cancer and neurodegenerative disease progression. These findings may aid in elucidating the underlying disease mechanisms. Here, we review the influence of non-canonical nucleic acid structures in disease-related genes on disease onset and progression.
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Affiliation(s)
- Hisae Tateishi-Karimata
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.,Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
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23
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Lyu K, Chow EYC, Mou X, Chan TF, Kwok CK. RNA G-quadruplexes (rG4s): genomics and biological functions. Nucleic Acids Res 2021; 49:5426-5450. [PMID: 33772593 PMCID: PMC8191793 DOI: 10.1093/nar/gkab187] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/02/2021] [Accepted: 03/24/2021] [Indexed: 02/07/2023] Open
Abstract
G-quadruplexes (G4s) are non-classical DNA or RNA secondary structures that have been first observed decades ago. Over the years, these four-stranded structural motifs have been demonstrated to have significant regulatory roles in diverse biological processes, but challenges remain in detecting them globally and reliably. Compared to DNA G4s (dG4s), the study of RNA G4s (rG4s) has received less attention until recently. In this review, we will summarize the innovative high-throughput methods recently developed to detect rG4s on a transcriptome-wide scale, highlight the many novel and important functions of rG4 being discovered in vivo across the tree of life, and discuss the key biological questions to be addressed in the near future.
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Affiliation(s)
- Kaixin Lyu
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Eugene Yui-Ching Chow
- School of Life Sciences, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Xi Mou
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Ting-Fung Chan
- School of Life Sciences, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
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24
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Abstract
G-quadruplexes are four-stranded helical nucleic acid structures characterized by stacked tetrads of guanosine bases. These structures are widespread throughout mammalian genomic DNA and RNA transcriptomes, and prevalent across all tissues. The role of G-quadruplexes in cancer is well-established, but there has been a growing exploration of these structures in the development and homeostasis of normal tissue. In this review, we focus on the roles of G-quadruplexes in directing gene expression in the nervous system, including the regulation of gene transcription, mRNA processing, and trafficking, as well as protein translation. The role of G-quadruplexes and their molecular interactions in the pathology of neurological diseases is also examined. Outside of cancer, there has been only limited exploration of G-quadruplexes as potential intervention targets to treat disease or injury. We discuss studies that have used small-molecule ligands to manipulate G-quadruplex stability in order to treat disease or direct neural stem/progenitor cell proliferation and differentiation into therapeutically relevant cell types. Understanding the many roles that G-quadruplexes have in the nervous system not only provides critical insight into fundamental molecular mechanisms that control neurological function, but also provides opportunities to identify novel therapeutic targets to treat injury and disease.
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Affiliation(s)
- John W Cave
- InVitro Cell Research LLC, Englewood, NJ, USA
| | - Dianna E Willis
- Burke Neurological Institute, White Plains, NY, USA.,Feil Family Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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25
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Cui Y, Li Z, Cao J, Lane J, Birkin E, Dong X, Zhang L, Jiang WG. The G4 Resolvase DHX36 Possesses a Prognosis Significance and Exerts Tumour Suppressing Function Through Multiple Causal Regulations in Non-Small Cell Lung Cancer. Front Oncol 2021; 11:655757. [PMID: 33987090 PMCID: PMC8111079 DOI: 10.3389/fonc.2021.655757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/06/2021] [Indexed: 12/19/2022] Open
Abstract
Lung cancer is one of the most prevalent cancers in both men and women worldwide. The nucleic acid G4 structures have been implicated in the transcriptional programmes of cancer-related genes in some cancers such as lung cancer. However, the role of the dominant G4 resolvase DHX36 in the progression of lung cancer remains unknown. In this study, by bioinformatic analysis of public datasets (TCGA and GEO), we find DHX36 is an independent prognosis indicator in non-small-cell lung carcinoma (NSCLC) with subtype dependence. The stable lentiviral knockdown of the DHX36 results in accelerated migration and aggregation of the S-phase subpopulation in lung cancer cells. The reduction of DHX36 level de-sensitises the proliferation response of lung cancer cells to chemotherapeutic drugs such as paclitaxel with cell dependence. The knockdown of this helicase leads to promoted tumour growth, demonstrated by a 3D fluorescence spheroid lung cancer model, and the stimulation of cell colony formation as shown by single-cell cultivation. High throughput proteomic array indicates that DHX36 functions in lung cancer cells through regulating multiple signalling pathways including activation of protein activity, protein autophosphorylation, Fc-receptor signalling pathway, response to peptide hormone and stress-activated protein kinase signalling cascade. A causal transcriptomic analysis suggests that DHX36 is significantly associated with mRNA surveillance, RNA degradation, DNA replication and Myc targets. Therefore, we unveil that DHX36 presents clinical significance and plays a role in tumour suppression in lung cancer, and propose a potentially new concept for an anti-cancer therapy based on helicase-specific targeting.
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Affiliation(s)
- Yuxin Cui
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Zhilei Li
- Department of Pharmacy, Zhujiang Hospital of Southern Medical University, Guangzhou, China
| | - Junxia Cao
- Biotherapy Center, The Seventh Medical Center of PLA General Hospital, Beijing, China
| | - Jane Lane
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Emily Birkin
- Cardiff & Vale University Health Board, University Hospital of Wales, Cardiff, United Kingdom
| | - Xuefei Dong
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Lijian Zhang
- Department of Thoracic Surgery, Peking University Cancer Hospital, Beijing, China
| | - Wen G Jiang
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, United Kingdom
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26
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Zhang R, Xiao K, Gu Y, Liu H, Sun X. Whole Genome Identification of Potential G-Quadruplexes and Analysis of the G-Quadruplex Binding Domain for SARS-CoV-2. Front Genet 2020; 11:587829. [PMID: 33329730 PMCID: PMC7728997 DOI: 10.3389/fgene.2020.587829] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/22/2020] [Indexed: 01/08/2023] Open
Abstract
The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has become a global public health emergency. G-quadruplex, one of the non-canonical secondary structures, has shown potential antiviral values. However, little is known about the G-quadruplexes of the emerging SARS-CoV-2. Herein, we characterized the potential G-quadruplexes in both positive and negative-sense viral strands. The identified potential G-quadruplexes exhibited similar features to the G-quadruplexes detected in the human transcriptome. Within some bat- and pangolin-related betacoronaviruses, the G-tracts rather than the loops were under heightened selective constraints. We also found that the amino acid sequence similar to SUD (SARS-unique domain) was retained in SARS-CoV-2 but depleted in some other coronaviruses that can infect humans. Further analysis revealed that the amino acid residues related to the binding affinity of G-quadruplexes were conserved among 16,466 SARS-CoV-2 samples. Moreover, the dimer of the SUD-homology structure in SARS-CoV-2 displayed similar electrostatic potential patterns to the SUD dimer from SARS. Considering the potential value of G-quadruplexes to serve as targets in antiviral strategy, our fundamental research could provide new insights for the SARS-CoV-2 drug discovery.
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Affiliation(s)
- Rongxin Zhang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Ke Xiao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Yu Gu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Hongde Liu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Xiao Sun
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
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27
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Sanchez-Martin V, Lopez-Pujante C, Soriano-Rodriguez M, Garcia-Salcedo JA. An Updated Focus on Quadruplex Structures as Potential Therapeutic Targets in Cancer. Int J Mol Sci 2020; 21:ijms21238900. [PMID: 33255335 PMCID: PMC7734589 DOI: 10.3390/ijms21238900] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023] Open
Abstract
Non-canonical, four-stranded nucleic acids secondary structures are present within regulatory regions in the human genome and transcriptome. To date, these quadruplex structures include both DNA and RNA G-quadruplexes, formed in guanine-rich sequences, and i-Motifs, found in cytosine-rich sequences, as their counterparts. Quadruplexes have been extensively associated with cancer, playing an important role in telomere maintenance and control of genetic expression of several oncogenes and tumor suppressors. Therefore, quadruplex structures are considered attractive molecular targets for cancer therapeutics with novel mechanisms of action. In this review, we provide a general overview about recent research on the implications of quadruplex structures in cancer, firstly gathering together DNA G-quadruplexes, RNA G-quadruplexes as well as DNA i-Motifs.
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Affiliation(s)
- Victoria Sanchez-Martin
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Microbiology Unit, University Hospital Virgen de las Nieves, Biosanitary Research Institute IBS, Granada, 18014 Granada, Spain
- Department of Biochemistry, Molecular Biology III and Immunology, University of Granada, 18016 Granada, Spain
| | - Carmen Lopez-Pujante
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
| | - Miguel Soriano-Rodriguez
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Centre for Intensive Mediterranean Agrosystems and Agri-food Biotechnology (CIAMBITAL), University of Almeria, 04001 Almeria, Spain
- Correspondence: (M.S.-R.); (J.A.G.-S.); Tel.: +34-958715500 (M.S.-R.); +34-958715500 (J.A.G.-S.)
| | - Jose A. Garcia-Salcedo
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Microbiology Unit, University Hospital Virgen de las Nieves, Biosanitary Research Institute IBS, Granada, 18014 Granada, Spain
- Correspondence: (M.S.-R.); (J.A.G.-S.); Tel.: +34-958715500 (M.S.-R.); +34-958715500 (J.A.G.-S.)
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28
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Fukunaga J, Nomura Y, Tanaka Y, Torigoe H, Nakamura Y, Sakamoto T, Kozu T. A G-quadruplex-forming RNA aptamer binds to the MTG8 TAFH domain and dissociates the leukemic AML1-MTG8 fusion protein from DNA. FEBS Lett 2020; 594:3477-3489. [PMID: 32870501 DOI: 10.1002/1873-3468.13914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 11/11/2022]
Abstract
MTG8 (RUNX1T1) is a fusion partner of AML1 (RUNX1) in the leukemic chromosome translocation t(8;21). The AML1-MTG8 fusion gene encodes a chimeric transcription factor. One of the highly conserved domains of MTG8 is TAFH which possesses homology with human TAF4 [TATA-box binding protein-associated factor]. To obtain specific inhibitors of the AML1-MTG8 fusion protein, we isolated RNA aptamers against the MTG8 TAFH domain using systematic evolution of ligands by exponential enrichment. All TAF aptamers contained guanine-rich sequences. Analyses of a TAF aptamer by NMR, CD, and mutagenesis revealed that it forms a parallel G-quadruplex structure in the presence of K+ . Furthermore, the aptamer could bind to the AML1-MTG8 fusion protein and dissociate the AML1-MTG8/DNA complex, suggesting that it can inhibit the dominant negative effects of AML1-MTG8 against normal AML1 function and serve as a potential therapeutic agent for leukemia.
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Affiliation(s)
- Junichi Fukunaga
- Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Japan
| | - Yusuke Nomura
- Department of Life and Environmental Sciences, Faculty of Engineering, Chiba Institute of Technology, Narashino, Japan.,Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Japan
| | - Yoichiro Tanaka
- Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Japan.,Facility for RI Research and Education, Instrumental Analysis Center, Research Initiatives and Promotion Organization, Yokohama National University, Hodogaya-ku, Japan
| | - Hidetaka Torigoe
- Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Japan
| | - Yoshikazu Nakamura
- Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, Minato-ku, Japan.,Ribomic Inc., Minato-ku, Japan
| | - Taiichi Sakamoto
- Department of Life and Environmental Sciences, Faculty of Engineering, Chiba Institute of Technology, Narashino, Japan
| | - Tomoko Kozu
- Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Japan
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29
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Abstract
DNA and RNA can adopt various secondary structures. Four-stranded G-quadruplex (G4) structures form through self-recognition of guanines into stacked tetrads, and considerable biophysical and structural evidence exists for G4 formation in vitro. Computational studies and sequencing methods have revealed the prevalence of G4 sequence motifs at gene regulatory regions in various genomes, including in humans. Experiments using chemical, molecular and cell biology methods have demonstrated that G4s exist in chromatin DNA and in RNA, and have linked G4 formation with key biological processes ranging from transcription and translation to genome instability and cancer. In this Review, we first discuss the identification of G4s and evidence for their formation in cells using chemical biology, imaging and genomic technologies. We then discuss possible functions of DNA G4s and their interacting proteins, particularly in transcription, telomere biology and genome instability. Roles of RNA G4s in RNA biology, especially in translation, are also discussed. Furthermore, we consider the emerging relationships of G4s with chromatin and with RNA modifications. Finally, we discuss the connection between G4 formation and synthetic lethality in cancer cells, and recent progress towards considering G4s as therapeutic targets in human diseases.
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Affiliation(s)
- Dhaval Varshney
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Jochen Spiegel
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Katherine Zyner
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - David Tannahill
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Shankar Balasubramanian
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK.
- Department of Chemistry, University of Cambridge, Cambridge, UK.
- School of Clinical Medicine, University of Cambridge, Cambridge, UK.
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30
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Simko EAJ, Liu H, Zhang T, Velasquez A, Teli S, Haeusler AR, Wang J. G-quadruplexes offer a conserved structural motif for NONO recruitment to NEAT1 architectural lncRNA. Nucleic Acids Res 2020; 48:7421-7438. [PMID: 32496517 PMCID: PMC7367201 DOI: 10.1093/nar/gkaa475] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 06/02/2020] [Indexed: 12/11/2022] Open
Abstract
The long non-coding RNA NEAT1 serves as a scaffold for the assembly of paraspeckles, membraneless nuclear organelles involved in gene regulation. Paraspeckle assembly requires NEAT1 recruitment of the RNA-binding protein NONO, however the NEAT1 elements responsible for recruitment are unknown. Herein we present evidence that previously unrecognized structural features of NEAT1 serve an important role in these interactions. Led by the initial observation that NONO preferentially binds the G-quadruplex conformation of G-rich C9orf72 repeat RNA, we find that G-quadruplex motifs are abundant and conserved features of NEAT1. Furthermore, we determine that NONO binds NEAT1 G-quadruplexes with structural specificity and provide evidence that G-quadruplex motifs mediate NONO-NEAT1 association, with NONO binding sites on NEAT1 corresponding largely to G-quadruplex motifs, and treatment with a G-quadruplex-disrupting small molecule causing dissociation of native NONO-NEAT1 complexes. Together, these findings position G-quadruplexes as a primary candidate for the NONO-recruiting elements of NEAT1 and provide a framework for further investigation into the role of G-quadruplexes in paraspeckle formation and function.
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Affiliation(s)
- Eric A J Simko
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Honghe Liu
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tao Zhang
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Adan Velasquez
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shraddha Teli
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Aaron R Haeusler
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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31
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Gazanion E, Lacroix L, Alberti P, Gurung P, Wein S, Cheng M, Mergny JL, Gomes AR, Lopez-Rubio JJ. Genome wide distribution of G-quadruplexes and their impact on gene expression in malaria parasites. PLoS Genet 2020; 16:e1008917. [PMID: 32628663 PMCID: PMC7365481 DOI: 10.1371/journal.pgen.1008917] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 07/16/2020] [Accepted: 06/08/2020] [Indexed: 12/15/2022] Open
Abstract
Mechanisms of transcriptional control in malaria parasites are still not fully understood. The positioning patterns of G-quadruplex (G4) DNA motifs in the parasite's AT-rich genome, especially within the var gene family which encodes virulence factors, and in the vicinity of recombination hotspots, points towards a possible regulatory role of G4 in gene expression and genome stability. Here, we carried out the most comprehensive genome-wide survey, to date, of G4s in the Plasmodium falciparum genome using G4Hunter, which identifies G4 forming sequences (G4FS) considering their G-richness and G-skewness. We show an enrichment of G4FS in nucleosome-depleted regions and in the first exon of var genes, a pattern that is conserved within the closely related Laverania Plasmodium parasites. Under G4-stabilizing conditions, i.e., following treatment with pyridostatin (a high affinity G4 ligand), we show that a bona fide G4 found in the non-coding strand of var promoters modulates reporter gene expression. Furthermore, transcriptional profiling of pyridostatin-treated parasites, shows large scale perturbations, with deregulation affecting for instance the ApiAP2 family of transcription factors and genes involved in ribosome biogenesis. Overall, our study highlights G4s as important DNA secondary structures with a role in Plasmodium gene expression regulation, sub-telomeric recombination and var gene biology.
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Affiliation(s)
- Elodie Gazanion
- MIVEGEC UMR IRD 224, CNRS 5290, Montpellier University, Montpellier, France
| | - Laurent Lacroix
- IBENS, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, Paris, France
| | - Patrizia Alberti
- "Structure and Instability of Genomes" laboratory, Muséum National d'Histoire Naturelle (MNHN), Inserm U1154, CNRS UMR 7196, Paris, France
| | - Pratima Gurung
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, CNRS, Montpellier University, Montpellier, France
| | - Sharon Wein
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, CNRS, Montpellier University, Montpellier, France
| | - Mingpan Cheng
- ARNA Laboratory, IECB, CNRS UMR5320, INSERM U1212, Bordeaux University, Pessac, France
| | - Jean-Louis Mergny
- ARNA Laboratory, IECB, CNRS UMR5320, INSERM U1212, Bordeaux University, Pessac, France
- Institute of Biophysics of the Czech Academy of Sciences, Czech Republic
- Laboratoire d’Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, France
| | - Ana Rita Gomes
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, CNRS, Montpellier University, Montpellier, France
| | - Jose-Juan Lopez-Rubio
- MIVEGEC UMR IRD 224, CNRS 5290, Montpellier University, Montpellier, France
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, CNRS, Montpellier University, Montpellier, France
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32
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Reina C, Cavalieri V. Epigenetic Modulation of Chromatin States and Gene Expression by G-Quadruplex Structures. Int J Mol Sci 2020; 21:E4172. [PMID: 32545267 PMCID: PMC7312119 DOI: 10.3390/ijms21114172] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/07/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
G-quadruplexes are four-stranded helical nucleic acid structures formed by guanine-rich sequences. A considerable number of studies have revealed that these noncanonical structural motifs are widespread throughout the genome and transcriptome of numerous organisms, including humans. In particular, G-quadruplexes occupy strategic locations in genomic DNA and both coding and noncoding RNA molecules, being involved in many essential cellular and organismal functions. In this review, we first outline the fundamental structural features of G-quadruplexes and then focus on the concept that these DNA and RNA structures convey a distinctive layer of epigenetic information that is critical for the complex regulation, either positive or negative, of biological activities in different contexts. In this framework, we summarize and discuss the proposed mechanisms underlying the functions of G-quadruplexes and their interacting factors. Furthermore, we give special emphasis to the interplay between G-quadruplex formation/disruption and other epigenetic marks, including biochemical modifications of DNA bases and histones, nucleosome positioning, and three-dimensional organization of chromatin. Finally, epigenetic roles of RNA G-quadruplexes in post-transcriptional regulation of gene expression are also discussed. Undoubtedly, the issues addressed in this review take on particular importance in the field of comparative epigenetics, as well as in translational research.
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Affiliation(s)
- Chiara Reina
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy;
| | - Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy
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33
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D’Aguanno S, Del Bufalo D. Inhibition of Anti-Apoptotic Bcl-2 Proteins in Preclinical and Clinical Studies: Current Overview in Cancer. Cells 2020; 9:cells9051287. [PMID: 32455818 PMCID: PMC7291206 DOI: 10.3390/cells9051287] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/30/2022] Open
Abstract
The dynamic interplay between pro-death and pro-survival Bcl-2 family proteins is responsible for a cell’s fate. Due to the recognized relevance of this family in cancer progression and response to therapy, different efforts have made in recent years in order to develop small molecules able to target anti-apoptotic proteins such as Bcl-2, Bcl-xL and Mcl-1. The limitations of the first Bcl-2 family targeted drugs, regarding on-target and off-target toxicities, have been overcome with the development of venetoclax (ABT-199), the first BH3 mimetic inhibitor approved by the FDA. The purpose of this review is to discuss the state-of-the-art in the development of drugs targeting Bcl-2 anti-apoptotic proteins and to highlight the potential of their application as single agents or in combination for improving anti-cancer therapy, focusing in particular on solid tumors.
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34
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Taylor J, Yeomans AM, Packham G. Targeted inhibition of mRNA translation initiation factors as a novel therapeutic strategy for mature B-cell neoplasms. Explor Target Antitumor Ther 2020; 1:3-25. [PMID: 32924027 PMCID: PMC7116065 DOI: 10.37349/etat.2020.00002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/31/2020] [Indexed: 12/17/2022] Open
Abstract
Cancer development is frequently associated with dysregulation of mRNA translation to enhance both increased global protein synthesis and translation of specific mRNAs encoding oncoproteins. Thus, targeted inhibition of mRNA translation is viewed as a promising new approach for cancer therapy. In this article we review current progress in investigating dysregulation of mRNA translation initiation in mature B-cell neoplasms, focusing on chronic lymphocytic leukemia, follicular lymphoma and diffuse large B-cell lymphoma. We discuss mechanisms and regulation of mRNA translation, potential pathways by which genetic alterations and the tumor microenvironment alters mRNA translation in malignant B cells, preclinical evaluation of drugs targeted against specific eukaryotic initiation factors and current progress towards clinical development. Overall, inhibition of mRNA translation initiation factors is an exciting and promising area for development of novel targeted anti-tumor drugs.
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Affiliation(s)
- Joe Taylor
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, SO16 6YD Southampton, United Kingdom
| | - Alison M Yeomans
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, SO16 6YD Southampton, United Kingdom
| | - Graham Packham
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, SO16 6YD Southampton, United Kingdom
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35
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Díaz-López I, Toribio R, Berlanga JJ, Ventoso I. An mRNA-binding channel in the ES6S region of the translation 48S-PIC promotes RNA unwinding and scanning. eLife 2019; 8:48246. [PMID: 31789591 PMCID: PMC6887119 DOI: 10.7554/elife.48246] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 11/16/2019] [Indexed: 11/30/2022] Open
Abstract
Loading of mRNA onto the ribosomal 43S pre-initiation complex (PIC) and its subsequent scanning require the removal of the secondary structure of the by RNA helicases such as eIF4A. However, the topology and mechanics of the scanning complex bound to mRNA (48S-PIC) and the influence of its solvent-side composition on the scanning process are poorly known. Here, we found that the ES6S region of the 48S-PIC constitutes an extended binding channel for eIF4A-mediated unwinding of mRNA and scanning. Blocking ES6S inhibited the cap-dependent translation of mRNAs that have structured 5′ UTRs (including G-quadruplexes), many of which are involved in signal transduction and growth, but it did not affect IRES-driven translation. Genome-wide analysis of mRNA translation revealed a great diversity in ES6S-mediated scanning dependency. Our data suggest that mRNA threading into the ES6S region makes scanning by 48S PIC slower but more processive. Hence, we propose a topological and functional model of the scanning 48S-PIC.
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Affiliation(s)
- Irene Díaz-López
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - René Toribio
- Centro de Biotecnología y Genómica de Plantas, Madrid, Spain
| | - Juan José Berlanga
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Iván Ventoso
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM), Madrid, Spain
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36
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Niu K, Xiang L, Jin Y, Peng Y, Wu F, Tang W, Zhang X, Deng H, Xiang H, Li S, Wang J, Song Q, Feng Q. Identification of LARK as a novel and conserved G-quadruplex binding protein in invertebrates and vertebrates. Nucleic Acids Res 2019; 47:7306-7320. [PMID: 31165881 PMCID: PMC6698653 DOI: 10.1093/nar/gkz484] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 05/14/2019] [Accepted: 05/29/2019] [Indexed: 12/30/2022] Open
Abstract
Double-stranded DNAs are usually present in the form of linear B-form double-helix with the base pairs of adenine (A) and thymine (T) or cytosine (C) and guanine (G), but G-rich DNA can form four-stranded G-quadruplex (G4) structures, which plays important roles in transcription, replication, translation and protection of telomeres. In this study, a RNA recognition motif (RRM)-containing protein, BmLARK, was identified and demonstrated to bind G4 structures in the promoters of a transcription factor BmPOUM2 and other three unidentified genes of Bombyx mori, as well as three well-defined G4 structures in the human genes. Homologous LARKs from Bombyx mori, Drosophila melanogaster, Mus musculus and Homo sapiens bound G4 structures in BmPOUM2 and other genes in B. mori and H. sapiens. Upon binding, LARK facilitated the formation and stability of the G4 structure, enhancing the transcription of target genes. The G4 structure was visualized in vivo in cells and testis from invertebrate B. mori and vertebrate Chinese hamster ovary (CHO) cells. The results of this study strongly suggest that LARK is a novel and conserved G4-binding protein and that the G4 structure may have developed into an elaborate epigenetic mechanism of gene transcription regulation during evolution.
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Affiliation(s)
- Kangkang Niu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Lijun Xiang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Ying Jin
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Yuling Peng
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Feng Wu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Wenhuan Tang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Xiaojuan Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Huimin Deng
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Hui Xiang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Jian Wang
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
| | - Qisheng Song
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Qili Feng
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
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Pany SPP, Sapra M, Sharma J, Dhamodharan V, Patankar S, Pradeepkumar PI. Presence of Potential G‐Quadruplex RNA‐Forming Motifs at the 5′‐UTR of
PP2Acα
mRNA Repress Translation. Chembiochem 2019; 20:2955-2960. [DOI: 10.1002/cbic.201900336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Indexed: 01/08/2023]
Affiliation(s)
| | - Mahak Sapra
- Centre for Research in Nanotechnology and ScienceIndian Institute of Technology Bombay Mumbai 400076 India
| | - Jitendar Sharma
- Department of ChemistryIndian Institute of Technology Bombay Mumbai 400076 India
| | - V. Dhamodharan
- Department of ChemistryIndian Institute of Technology Bombay Mumbai 400076 India
| | - Swati Patankar
- Department of Bioscience and BioengineeringIndian Institute of Technology Bombay Mumbai 400076 India
| | - P. I. Pradeepkumar
- Department of ChemistryIndian Institute of Technology Bombay Mumbai 400076 India
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38
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Kharel P, Balaratnam S, Beals N, Basu S. The role of RNA G-quadruplexes in human diseases and therapeutic strategies. Wiley Interdiscip Rev RNA 2019; 11:e1568. [PMID: 31514263 DOI: 10.1002/wrna.1568] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 08/09/2019] [Accepted: 08/27/2019] [Indexed: 12/13/2022]
Abstract
G-quadruplexes (GQs) are four-stranded secondary structures formed by G-rich nucleic acid sequence(s). DNA GQs are present abundantly in the genome and affect a wide range of processes associated with DNA. Recent studies show that RNA GQs are present in different transcripts, including coding and noncoding areas of mRNA, telomeric RNA as well as in other premature and mature noncoding RNAs. When present at specific locations within the RNAs, GQs play important roles in key biological functions, including the regulation of gene expression and telomere homeostasis. RNA GQs regulate pre-mRNA processing, such as splicing and polyadenylation. Evidently, among other processes, RNA GQs also control mRNA translation, miRNA and piRNA biogenesis, and RNA localization. The regulatory mechanisms controlled by RNA GQs mainly involve binding to RNA binding protein that modulate GQ conformation or serve as an entity in recruiting additional protein regulators to act as a block element to the processing machinery. Here we provide an overview of the ever-increasing number of discoveries revealing the role of RNA GQs in biology and their relevance in human diseases and therapeutics. This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Prakash Kharel
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio.,Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Sumirtha Balaratnam
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio.,Chemical Biology Laboratory, National Cancer Institute, Frederick, Maryland
| | - Nathan Beals
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York
| | - Soumitra Basu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio
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39
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Agarwala P, Pandey S, Ekka MK, Chakraborty D, Maiti S. Combinatorial role of two G-quadruplexes in 5' UTR of transforming growth factor β2 (TGFβ2). Biochim Biophys Acta Gen Subj 2019; 1863:129416. [PMID: 31425729 DOI: 10.1016/j.bbagen.2019.129416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/14/2019] [Accepted: 08/13/2019] [Indexed: 11/25/2022]
Abstract
Albeit most studies demonstrate the inhibitory role of G-quadruplex in the 5' Untranslated Region (5' UTR), our previous report depicted its completely contrasting activating role in the 5' UTR of transforming growth factor β2 (TGFβ2) mRNA. Therefore, we screened the 5' UTR of TGFβ2 manually and identified a second putative G-quadruplex sequence. Our in vitro experiments encompassing CD and UV spectroscopy confirmed the ability of this sequence to form a G-quadruplex and in cellulo studies further indicated its activating role in modulation of TGFβ2 gene expression. Our study suggests that these two 5' UTR G-quadruplexes most probably operate additively to substantially increase gene expression of TGFβ2. Neither of the two G-quadruplex alone is sufficient enough to drastically augment protein production. Both G-quadruplexes are essential for increasing protein output. To the best of our knowledge, our study is the first report showcasing the combinatorial role of two G-quadruplexes in the 5' UTR of an mRNA.
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Affiliation(s)
- Prachi Agarwala
- Proteomics and Structural Biology Unit, CSIR, Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Satyaprakash Pandey
- Proteomics and Structural Biology Unit, CSIR, Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Mary Krishna Ekka
- Proteomics and Structural Biology Unit, CSIR, Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Debojyoti Chakraborty
- Proteomics and Structural Biology Unit, CSIR, Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Souvik Maiti
- Proteomics and Structural Biology Unit, CSIR, Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India.
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40
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Al-Zeer MA, Dutkiewicz M, von Hacht A, Kreuzmann D, Röhrs V, Kurreck J. Alternatively spliced variants of the 5'-UTR of the ARPC2 mRNA regulate translation by an internal ribosome entry site (IRES) harboring a guanine-quadruplex motif. RNA Biol 2019; 16:1622-1632. [PMID: 31387452 DOI: 10.1080/15476286.2019.1652524] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The 5'-UTR of the actin-related protein 2/3 complex subunit 2 (ARPC2) mRNA exists in two variants. Using a bicistronic reporter construct, the present study demonstrates that the longer variant of the 5'-UTR harbours an internal ribosome entry site (IRES) which is lacking in the shorter one. Multiple control assays confirmed that only this variant promotes cap-independent translation. Furthermore, it includes a guanine-rich region that is capable of forming a guanine-quadruplex (G-quadruplex) structure which was found to contribute to the IRES activity. To investigate the cellular function of the IRES element, we determined the expression level of ARPC2 at various cell densities. At high cell density, the relative ARPC2 protein level increases, supporting the presumed function of IRES elements in driving the expression of certain genes under stressful conditions that compromise cap-dependent translation. Based on chemical probing experiments and computer-based predictions, we propose a structural model of the IRES element, which includes the G-quadruplex motif exposed from the central stem-loop element. Taken together, our study describes the functional relevance of two alternative 5'-UTR splice variants of the ARPC2 mRNA, one of which contains an IRES element with a G-quadruplex as a central motif, promoting translation under stressful cellular conditions.
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Affiliation(s)
- Munir A Al-Zeer
- Institute of Biotechnology, Technische Universität Berlin , Berlin , Germany
| | - Mariola Dutkiewicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences , Poznan , Poland
| | | | - Denise Kreuzmann
- Institute of Biotechnology, Technische Universität Berlin , Berlin , Germany
| | - Viola Röhrs
- Institute of Biotechnology, Technische Universität Berlin , Berlin , Germany
| | - Jens Kurreck
- Institute of Biotechnology, Technische Universität Berlin , Berlin , Germany
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41
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Waldron JA, Raza F, Le Quesne J. eIF4A alleviates the translational repression mediated by classical secondary structures more than by G-quadruplexes. Nucleic Acids Res 2019; 46:3075-3087. [PMID: 29471358 PMCID: PMC5888628 DOI: 10.1093/nar/gky108] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/13/2018] [Indexed: 01/02/2023] Open
Abstract
Increased activity of the mRNA helicase eIF4A drives cellular malignancy by reprogramming cellular translation, and eIF4A activity is the direct or indirect target of many emerging cancer therapeutics. The enriched presence of (GGC)4 motifs, which have the potential to fold into two-layered G-quadruplexes, within the 5'UTRs of eIF4A-dependent mRNAs suggests that eIF4A is required for the unwinding of these structures within these eIF4A-controlled mRNAs. However, the existence of folded G-quadruplexes within cells remains controversial, and G-quadruplex folding is in direct competition with classical Watson-Crick based secondary structures. Using a combination of reverse transcription stalling assays and 7-deazaguanine incorporation experiments we find that (GGC)4 motifs preferentially form classical secondary structures rather than G-quadruplexes in full-length mRNAs. Furthermore, using translation assays with the eIF4A inhibitor hippuristanol, both in vitro and in cells, we find that eIF4A activity alleviates translational repression of mRNAs with 5'UTR classical secondary structures significantly more than those with folded G-quadruplexes. This was particularly evident in experiments using a G-quadruplex stabilizing ligand, where shifting the structural equilibrium in favour of G-quadruplex formation diminishes eIF4A-dependency. This suggests that enrichment of (GGC)4 motifs in the 5'UTRs of eIF4A-dependent mRNAs is due to the formation of stable hairpin structures rather than G-quadruplexes.
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Affiliation(s)
| | | | - John Le Quesne
- MRC Toxicology Unit, Leicester, UK.,Leicester Cancer Research Centre, University of Leicester, Leicester, UK
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42
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Herdy B, Mayer C, Varshney D, Marsico G, Murat P, Taylor C, D'Santos C, Tannahill D, Balasubramanian S. Analysis of NRAS RNA G-quadruplex binding proteins reveals DDX3X as a novel interactor of cellular G-quadruplex containing transcripts. Nucleic Acids Res 2019; 46:11592-11604. [PMID: 30256975 PMCID: PMC6265444 DOI: 10.1093/nar/gky861] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/12/2018] [Indexed: 12/23/2022] Open
Abstract
RNA G-quadruplexes (rG4s) are secondary structures in mRNAs known to influence RNA post-transcriptional mechanisms thereby impacting neurodegenerative disease and cancer. A detailed knowledge of rG4–protein interactions is vital to understand rG4 function. Herein, we describe a systematic affinity proteomics approach that identified 80 high-confidence interactors that assemble on the rG4 located in the 5′-untranslated region (UTR) of the NRAS oncogene. Novel rG4 interactors included DDX3X, DDX5, DDX17, GRSF1 and NSUN5. The majority of identified proteins contained a glycine-arginine (GAR) domain and notably GAR-domain mutation in DDX3X and DDX17 abrogated rG4 binding. Identification of DDX3X targets by transcriptome-wide individual-nucleotide resolution UV-crosslinking and affinity enrichment (iCLAE) revealed a striking association with 5′-UTR rG4-containing transcripts which was reduced upon GAR-domain mutation. Our work highlights hitherto unrecognized features of rG4 structure–protein interactions that highlight new roles of rG4 structures in mRNA post-transcriptional control.
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Affiliation(s)
- Barbara Herdy
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Clemens Mayer
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands.,Department of Chemistry, University of Cambridge Lensfield Road, Cambridge CB2 1EW, UK
| | - Dhaval Varshney
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Giovanni Marsico
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Pierre Murat
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.,Department of Chemistry, University of Cambridge Lensfield Road, Cambridge CB2 1EW, UK
| | - Chris Taylor
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.,Bioscience Technology Facility, Department of Biology, University of York, York YO10 5DD, UK
| | - Clive D'Santos
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - David Tannahill
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Shankar Balasubramanian
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.,Department of Chemistry, University of Cambridge Lensfield Road, Cambridge CB2 1EW, UK
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43
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Sengupta P, Bhattacharya A, Sa G, Das T, Chatterjee S. Truncated G-Quadruplex Isomers Cross-Talk with the Transcription Factors To Maintain Homeostatic Equilibria in c-MYC Transcription. Biochemistry 2019; 58:1975-1991. [PMID: 30920805 DOI: 10.1021/acs.biochem.9b00030] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nuclease hypersensitive element III1 (NHE III1) upstream c-MYC promoter harbors a transcription-silencing G-quadruplex (Pu27) element. Dynamic turnover of various transcription factors (TFs) across Pu27 to control c-MYC transcription homeostasis is enigmatic. Here, we reveal that native Pu27 evolves truncated G-quadruplex isomers (Pu19, Pu22, Pu24, and Pu25) in cells that are optimal intracellular targets of specific TFs in a sequence- and structure-dependent manner. Nuclear magnetic resonance and isothermal titration calorimetry envisaged that NM23-H2 (nucleoside diphosphate kinase) and nucleolin induce conformational fluctuations in Pu27 to sample specific conformationally restricted conformer(s). Structural investigations revealed that the flanking guanines at 5'-Pu27 control solvent exposure at G-quartets upon NM23-H2 and nucleolin binding driving Pu27 unfolding and folding, respectively. Transient chromatin immunoprecipitations confirmed that NM23-H2 drives the conformation switch to Pu24 that outcompetes nucleolin recruitment. Similarly, nucleolin arrests Pu27 in the Pu22 conformer minimizing NM23-H2 binding at Pu27. hnRNPK (heterogeneous nuclear ribonucleoprotein K) positively regulates NM23-H2 and nucleolin association at Pu27 despite their antagonism. On the basis of these results, we simulated the transcription kinetics in a feed-forward loop in which the transcription output responds to hnRNPK-induced early activation via NM23-H2 association, which favors Pu24 formation at NHE III1 reducing nucleolin occupancy and driving quadruplex unfolding to initiate transcription. NM23-H2 further promotes hnRNPK deposition across NHE III1 altering Pu27 plasticity that finally enriches the nucleolin abundance to drive Pu22 formation and weaken NM23-H2 binding to extinguish transcription. This mechanism involves three positive feedback loops (NM23-H2-hnRNPK, NM23-H2-CNBP, and hnRNPK-nucleolin) and one negative feedback loop (NM23-H2-nucleolin) controlling optimal turnover and residence time of TFs at Pu27 to homeostatically regulate c-MYC transcription.
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Affiliation(s)
- Pallabi Sengupta
- Department of Biophysics , Bose Institute , P 1/12, C. I. T. Road, Scheme-VIIM , Kolkata 700054 , West Bengal , India
| | - Apoorva Bhattacharya
- Division of Molecular Medicine , Bose Institute , P 1/12, C. I. T. Road, Scheme-VIIM , Kolkata 700054 , West Bengal , India
| | - Gaurisankar Sa
- Division of Molecular Medicine , Bose Institute , P 1/12, C. I. T. Road, Scheme-VIIM , Kolkata 700054 , West Bengal , India
| | - Tanya Das
- Division of Molecular Medicine , Bose Institute , P 1/12, C. I. T. Road, Scheme-VIIM , Kolkata 700054 , West Bengal , India
| | - Subhrangsu Chatterjee
- Department of Biophysics , Bose Institute , P 1/12, C. I. T. Road, Scheme-VIIM , Kolkata 700054 , West Bengal , India
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44
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Yu L, Yang Q, Tang Y. A comparative study of assembly and disassembly process of dimeric and monomeric cyanine dyes with DNA templates. CHINESE CHEM LETT 2019; 30:694-7. [DOI: 10.1016/j.cclet.2018.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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45
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Li W, Zeng W, Chen Y, Wang F, Wu F, Weng X, Zhou X. Biotinylation and isolation of an RNA G-quadruplex based on its peroxidase-mimicking activity. Analyst 2019; 144:4472-4476. [DOI: 10.1039/c9an00353c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The selective biotinylation of RNA G-quadruplexes can be used for pulling down RNA G-quadruplexes from an RNA mixture.
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Affiliation(s)
- Wei Li
- College of Chemistry and Molecular Sciences
- Key Laboratory of Biomedical Polymers of Ministry of Education
- The Institute for Advanced Studies
- Hubei Province Key Laboratory of Allergy and Immunology
- Wuhan University
| | - Weiwu Zeng
- College of Chemistry and Molecular Sciences
- Key Laboratory of Biomedical Polymers of Ministry of Education
- The Institute for Advanced Studies
- Hubei Province Key Laboratory of Allergy and Immunology
- Wuhan University
| | - Yi Chen
- College of Chemistry and Molecular Sciences
- Key Laboratory of Biomedical Polymers of Ministry of Education
- The Institute for Advanced Studies
- Hubei Province Key Laboratory of Allergy and Immunology
- Wuhan University
| | - Fang Wang
- Wuhan University School of Pharmaceutical Sciences
- Wuhan University
- Wuhan 430071
- China
| | - Fan Wu
- College of Chemistry and Molecular Sciences
- Key Laboratory of Biomedical Polymers of Ministry of Education
- The Institute for Advanced Studies
- Hubei Province Key Laboratory of Allergy and Immunology
- Wuhan University
| | - Xiaocheng Weng
- College of Chemistry and Molecular Sciences
- Key Laboratory of Biomedical Polymers of Ministry of Education
- The Institute for Advanced Studies
- Hubei Province Key Laboratory of Allergy and Immunology
- Wuhan University
| | - Xiang Zhou
- College of Chemistry and Molecular Sciences
- Key Laboratory of Biomedical Polymers of Ministry of Education
- The Institute for Advanced Studies
- Hubei Province Key Laboratory of Allergy and Immunology
- Wuhan University
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46
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Azargun M, Meister PJ, Gauld JW, Fridgen TD. The K2(9-ethylguanine)122+ quadruplex is more stable to unimolecular dissociation than the K(9-ethylguanine)8+ quadruplex in the gas phase: a BIRD, energy resolved SORI-CID, IRMPD spectroscopic, and computational study. Phys Chem Chem Phys 2019; 21:15319-15326. [DOI: 10.1039/c9cp01651a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of experimental trapped-ion mass spectrometric studies and computational chemistry has been used to assess the intrinsic properties of the potassiated 9-ethylguanine (9eG) self-assembled quadruplex, K2(9eG)122+, in the gas phase.
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Affiliation(s)
- Mohammad Azargun
- Department of Chemistry
- Memorial University of Newfoundland
- St. John's
- Canada
| | - Paul J. Meister
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
| | - James W. Gauld
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
| | - Travis D. Fridgen
- Department of Chemistry
- Memorial University of Newfoundland
- St. John's
- Canada
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47
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Vester K, Eravci M, Serikawa T, Schütze T, Weise C, Kurreck J. RNAi-mediated knockdown of the Rhau helicase preferentially depletes proteins with a Guanine-quadruplex motif in the 5'-UTR of their mRNA. Biochem Biophys Res Commun 2019; 508:756-761. [DOI: 10.1016/j.bbrc.2018.11.186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 11/28/2018] [Indexed: 12/11/2022]
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48
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Murat P, Marsico G, Herdy B, Ghanbarian AT, Portella G, Balasubramanian S. RNA G-quadruplexes at upstream open reading frames cause DHX36- and DHX9-dependent translation of human mRNAs. Genome Biol 2018; 19:229. [PMID: 30591072 PMCID: PMC6307142 DOI: 10.1186/s13059-018-1602-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 12/04/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND RNA secondary structures in the 5'-untranslated regions (5'-UTR) of mRNAs are key to the post-transcriptional regulation of gene expression. While it is evident that non-canonical Hoogsteen-paired G-quadruplex (rG4) structures somehow contribute to the regulation of translation initiation, the nature and extent of human mRNAs that are regulated by rG4s is not known. Here, we provide new insights into a mechanism by which rG4 formation modulates translation. RESULTS Using transcriptome-wide ribosome profiling, we identify rG4-driven mRNAs in HeLa cells and reveal that rG4s in the 5'-UTRs of inefficiently translated mRNAs associate with high ribosome density and the translation of repressive upstream open reading frames (uORF). We demonstrate that depletion of the rG4-unwinding helicases DHX36 and DHX9 promotes translation of rG4-associated uORFs while reducing the translation of coding regions for transcripts that comprise proto-oncogenes, transcription factors and epigenetic regulators. Transcriptome-wide identification of DHX9 binding sites shows that reduced translation is mediated through direct physical interaction between the helicase and its rG4 substrate. CONCLUSION This study identifies human mRNAs whose translation efficiency is modulated by the DHX36- and DHX9-dependent folding/unfolding of rG4s within their 5'-UTRs. We reveal a previously unknown mechanism for translation regulation in which unresolved rG4s within 5'-UTRs promote 80S ribosome formation on upstream start codons, causing inhibition of translation of the downstream main open reading frames. Our findings suggest that the interaction of helicases with rG4s could be targeted for future therapeutic intervention.
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Affiliation(s)
- Pierre Murat
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Giovanni Marsico
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Barbara Herdy
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Avazeh T Ghanbarian
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Guillem Portella
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Shankar Balasubramanian
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK.
- School of Clinical Medicine, University of Cambridge, Cambridge, CB2 0SP, UK.
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Yamaguchi K, Asakura K, Imamura M, Kawai G, Sakamoto T, Furihata T, Linhardt RJ, Igarashi K, Toida T, Higashi K. Polyamines stimulate the CHSY1 synthesis through the unfolding of the RNA G-quadruplex at the 5'-untraslated region. Biochem J 2018; 475:3797-812. [PMID: 30401686 DOI: 10.1042/BCJ20180672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/04/2018] [Accepted: 11/05/2018] [Indexed: 01/20/2023]
Abstract
Glycosaminoglycans (GAGs), a group of structurally related acidic polysaccharides, are primarily found as glycan moieties of proteoglycans (PGs). Among these, chondroitin sulfate (CS) and dermatan sulfate, side chains of PGs, are widely distributed in animal kingdom and show structural variations, such as sulfation patterns and degree of epimerization, which are responsible for their physiological functions through interactions with growth factors, chemokines and adhesion molecules. However, structural changes in CS, particularly the ratio of 4-O-sulfation to 6-O-sulfation (4S/6S) and CS chain length that occur during the aging process, are not fully understood. We found that 4S/6S ratio and molecular weight of CS were decreased in polyamine-depleted cells. In addition, decreased levels of chondroitin synthase 1 (CHSY1) and chondroitin 4-O-sulfotransferase 2 proteins were also observed on polyamine depletion. Interestingly, the translation initiation of CHSY1 was suppressed by a highly structured sequence (positions -202 to -117 relative to the initiation codon) containing RNA G-quadruplex (G4) structures in 5'-untranslated region. The formation of the G4s was influenced by the neighboring sequences to the G4s and polyamine stimulation of CHSY1 synthesis disappeared when the formation of the G4s was inhibited by site-directed mutagenesis. These results suggest that the destabilization of G4 structures by polyamines stimulates CHSY1 synthesis and, at least in part, contribute to the maturation of CS chains.
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Abstract
RNA G-quadruplexes (rG4) are stable non-canonical secondary structures composed of G-rich sequences. Many rG4 structures located in the 5'UTRs of mRNAs act as translation repressors due to their high stability which is thought to impede ribosomal scanning. That said, it is not known if these are mRNA-specific examples, or if they are indicative of a global expression regulation mechanism of the mRNAs involved in a common pathway based on structure folding recognition. Gene-ontology analysis of mRNAs bearing a predicted rG4 motif in their 5'UTRs revealed an enrichment for mRNAs associated with the colorectal cancer pathway. Bioinformatic tools for rG4 prediction, and experimental in vitro validations were used to confirm and compare the folding of the predicted rG4s of the mRNAs associated with dysregulated pathways in colorectal cancer. The rG4 folding was confirmed for the first time for 9 mRNAs. A repressive effect of 3 rG4 candidates on the expression of a reporter gene was also measured in colorectal cancer cell lines. This work highlights the fact that rG4 prediction is not yet accurate, and that experimental characterization is still essential in order to identify the precise rG4 folding sequences and the possible common features shared between the rG4 overrepresented in important biological pathways.
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Affiliation(s)
- Rachel Jodoin
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Pierre Perreault
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
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