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Correll CC, Rudloff U, Schmit JD, Ball DA, Karpova TS, Balzer E, Dundr M. Crossing boundaries of light microscopy resolution discerns novel assemblies in the nucleolus. Histochem Cell Biol 2024; 162:161-183. [PMID: 38758429 PMCID: PMC11330670 DOI: 10.1007/s00418-024-02297-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2024] [Indexed: 05/18/2024]
Abstract
The nucleolus is the largest membraneless organelle and nuclear body in mammalian cells. It is primarily involved in the biogenesis of ribosomes, essential macromolecular machines responsible for synthesizing all proteins required by the cell. The assembly of ribosomes is evolutionarily conserved and accounts for the most energy-consuming cellular process needed for cell growth, proliferation, and homeostasis. Despite the significance of this process, the substructural mechanistic principles of the nucleolar function in preribosome biogenesis have only recently begun to emerge. Here, we provide a new perspective using advanced super-resolution microscopy and single-molecule MINFLUX nanoscopy on the mechanistic principles governing ribosomal RNA-seeded nucleolar formation and the resulting tripartite suborganization of the nucleolus driven, in part, by liquid-liquid phase separation. With recent advances in the cryogenic electron microscopy (cryoEM) structural analysis of ribosome biogenesis intermediates, we highlight the current understanding of the step-wise assembly of preribosomal subunits in the nucleolus. Finally, we address how novel anticancer drug candidates target early steps in ribosome biogenesis to exploit these essential dependencies for growth arrest and tumor control.
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Affiliation(s)
- Carl C Correll
- Center for Proteomics and Molecular Therapeutics and Biochemistry and Molecular Biology, Chicago Medical School, Rosalind Franklin University of Medicine & Science, North Chicago, IL, 60064, USA
| | - Udo Rudloff
- Rare Tumor Initiative, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jeremy D Schmit
- Department of Physics, Kansas State University, Manhattan, KS, 66506, USA
| | - David A Ball
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tatiana S Karpova
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eric Balzer
- Nikon Instruments Inc., Melville, NY, 11747, USA
| | - Miroslav Dundr
- Rare Tumor Initiative, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
- Center for Cancer Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine & Science, North Chicago, IL, 60064, USA.
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2
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González-Arzola K. The nucleolus: Coordinating stress response and genomic stability. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195029. [PMID: 38642633 DOI: 10.1016/j.bbagrm.2024.195029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 04/22/2024]
Abstract
The perception that the nucleoli are merely the organelles where ribosome biogenesis occurs is challenged. Only around 30 % of nucleolar proteins are solely involved in producing ribosomes. Instead, the nucleolus plays a critical role in controlling protein trafficking during stress and, according to its dynamic nature, undergoes continuous protein exchange with nucleoplasm under various cellular stressors. Hence, the concept of nucleolar stress has evolved as cellular insults that disrupt the structure and function of the nucleolus. Considering the emerging role of this organelle in DNA repair and the fact that rDNAs are the most fragile genomic loci, therapies targeting the nucleoli are increasingly being developed. Besides, drugs that target ribosome synthesis and induce nucleolar stress can be used in cancer therapy. In contrast, agents that regulate nucleolar activity may be a potential treatment for neurodegeneration caused by abnormal protein accumulation in the nucleolus. Here, I explore the roles of nucleoli beyond their ribosomal functions, highlighting the factors triggering nucleolar stress and their impact on genomic stability.
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Affiliation(s)
- Katiuska González-Arzola
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, 41012 Seville, Spain.
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3
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Toure MA, Motoyama K, Xiang Y, Urgiles J, Kabinger F, Koglin AS, Iyer RS, Gagnon K, Kumar A, Ojeda S, Harrison DA, Rees MG, Roth JA, Ott CJ, Schiavoni R, Whittaker CA, Levine SS, White FM, Calo E, Richters A, Koehler AN. Targeted Degradation of CDK9 Potently Disrupts the MYC Transcriptional Network. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.14.593352. [PMID: 38952800 PMCID: PMC11216368 DOI: 10.1101/2024.05.14.593352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Cyclin-dependent kinase 9 (CDK9) coordinates signaling events that regulate RNA polymerase II (Pol II) pause-release states. It is an important co-factor for transcription factors, such as MYC, that drive aberrant cell proliferation when their expression is deregulated. CDK9 modulation offers an approach for attenuating dysregulation in such transcriptional programs. As a result, numerous drug development campaigns to inhibit CDK9 kinase activity have been pursued. More recently, targeted degradation has emerged as an attractive approach. However, comprehensive evaluation of degradation versus inhibition is still critically needed to assess the biological contexts in which degradation might offer superior therapeutic benefits. We validated that CDK9 inhibition triggers a compensatory mechanism that dampens its effect on MYC expression and found that this feedback mechanism was absent when the kinase is degraded. Importantly, CDK9 degradation is more effective than its inhibition for disrupting MYC transcriptional regulatory circuitry likely through the abrogation of both enzymatic and scaffolding functions of CDK9. Highlights - KI-CDK9d-32 is a highly potent and selective CDK9 degrader. - KI-CDK9d-32 leads to rapid downregulation of MYC protein and mRNA transcripts levels. - KI-CDK9d-32 represses canonical MYC pathways and leads to a destabilization of nucleolar homeostasis. - Multidrug resistance ABCB1 gene emerged as the strongest resistance marker for the CDK9 PROTAC degrader.
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4
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Potapova TA, Unruh JR, Conkright-Fincham J, Banks CAS, Florens L, Schneider DA, Gerton JL. Distinct states of nucleolar stress induced by anticancer drugs. eLife 2023; 12:RP88799. [PMID: 38099650 PMCID: PMC10723795 DOI: 10.7554/elife.88799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Ribosome biogenesis is a vital and highly energy-consuming cellular function occurring primarily in the nucleolus. Cancer cells have an elevated demand for ribosomes to sustain continuous proliferation. This study evaluated the impact of existing anticancer drugs on the nucleolus by screening a library of anticancer compounds for drugs that induce nucleolar stress. For a readout, a novel parameter termed 'nucleolar normality score' was developed that measures the ratio of the fibrillar center and granular component proteins in the nucleolus and nucleoplasm. Multiple classes of drugs were found to induce nucleolar stress, including DNA intercalators, inhibitors of mTOR/PI3K, heat shock proteins, proteasome, and cyclin-dependent kinases (CDKs). Each class of drugs induced morphologically and molecularly distinct states of nucleolar stress accompanied by changes in nucleolar biophysical properties. In-depth characterization focused on the nucleolar stress induced by inhibition of transcriptional CDKs, particularly CDK9, the main CDK that regulates RNA Pol II. Multiple CDK substrates were identified in the nucleolus, including RNA Pol I- recruiting protein Treacle, which was phosphorylated by CDK9 in vitro. These results revealed a concerted regulation of RNA Pol I and Pol II by transcriptional CDKs. Our findings exposed many classes of chemotherapy compounds that are capable of inducing nucleolar stress, and we recommend considering this in anticancer drug development.
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Affiliation(s)
| | - Jay R Unruh
- Stowers Institute for Medical ResearchKansas CityUnited States
| | | | | | | | - David Alan Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at BirminghamBirminghamUnited States
| | - Jennifer L Gerton
- Stowers Institute for Medical ResearchKansas CityUnited States
- Department of Biochemistry and Molecular Biology, University of Kansas Medical CenterKansas CityUnited States
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5
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Berry S, Müller M, Rai A, Pelkmans L. Feedback from nuclear RNA on transcription promotes robust RNA concentration homeostasis in human cells. Cell Syst 2022; 13:454-470.e15. [PMID: 35613616 DOI: 10.1016/j.cels.2022.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 12/13/2021] [Accepted: 04/21/2022] [Indexed: 12/18/2022]
Abstract
RNA concentration homeostasis involves coordinating RNA abundance and synthesis rates with cell size. Here, we study this in human cells by combining genome-wide perturbations with quantitative single-cell measurements. Despite relative ease in perturbing RNA synthesis, we find that RNA concentrations generally remain highly constant. Perturbations that would be expected to increase nuclear mRNA levels, including those targeting nuclear mRNA degradation or export, result in downregulation of RNA synthesis. This is associated with reduced abundance of transcription-associated proteins and protein states that are normally coordinated with RNA production in single cells, including RNA polymerase II (RNA Pol II) itself. Acute perturbations, elevation of nuclear mRNA levels, and mathematical modeling indicate that mammalian cells achieve robust mRNA concentration homeostasis by the mRNA-based negative feedback on transcriptional activity in the nucleus. This ultimately acts to coordinate RNA Pol II abundance with nuclear mRNA degradation and export rates and may underpin the scaling of mRNA abundance with cell size.
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Affiliation(s)
- Scott Berry
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland; EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
| | - Micha Müller
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Arpan Rai
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Lucas Pelkmans
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.
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6
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Targeting Ribosome Biogenesis in Cancer: Lessons Learned and Way Forward. Cancers (Basel) 2022; 14:cancers14092126. [PMID: 35565259 PMCID: PMC9100539 DOI: 10.3390/cancers14092126] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/18/2022] [Accepted: 04/22/2022] [Indexed: 01/05/2023] Open
Abstract
Simple Summary Cells need to produce ribosomes to sustain continuous proliferation and expand in numbers, a feature that is even more prominent in uncontrollably proliferating cancer cells. Certain cancer cell types are expected to depend more on ribosome biogenesis based on their genetic background, and this potential vulnerability can be exploited in designing effective, targeted cancer therapies. This review provides information on anti-cancer molecules that target the ribosome biogenesis machinery and indicates avenues for future research. Abstract Rapid growth and unrestrained proliferation is a hallmark of many cancers. To accomplish this, cancer cells re-wire and increase their biosynthetic and metabolic activities, including ribosome biogenesis (RiBi), a complex, highly energy-consuming process. Several chemotherapeutic agents used in the clinic impair this process by interfering with the transcription of ribosomal RNA (rRNA) in the nucleolus through the blockade of RNA polymerase I or by limiting the nucleotide building blocks of RNA, thereby ultimately preventing the synthesis of new ribosomes. Perturbations in RiBi activate nucleolar stress response pathways, including those controlled by p53. While compounds such as actinomycin D and oxaliplatin effectively disrupt RiBi, there is an ongoing effort to improve the specificity further and find new potent RiBi-targeting compounds with improved pharmacological characteristics. A few recently identified inhibitors have also become popular as research tools, facilitating our advances in understanding RiBi. Here we provide a comprehensive overview of the various compounds targeting RiBi, their mechanism of action, and potential use in cancer therapy. We discuss screening strategies, drug repurposing, and common problems with compound specificity and mechanisms of action. Finally, emerging paths to discovery and avenues for the development of potential biomarkers predictive of therapeutic outcomes across cancer subtypes are also presented.
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Commuting to Work: Nucleolar Long Non-Coding RNA Control Ribosome Biogenesis from Near and Far. Noncoding RNA 2021; 7:ncrna7030042. [PMID: 34287370 PMCID: PMC8293466 DOI: 10.3390/ncrna7030042] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 12/26/2022] Open
Abstract
Gene expression is an essential process for cellular growth, proliferation, and differentiation. The transcription of protein-coding genes and non-coding loci depends on RNA polymerases. Interestingly, numerous loci encode long non-coding (lnc)RNA transcripts that are transcribed by RNA polymerase II (RNAPII) and fine-tune the RNA metabolism. The nucleolus is a prime example of how different lncRNA species concomitantly regulate gene expression by facilitating the production and processing of ribosomal (r)RNA for ribosome biogenesis. Here, we summarise the current findings on how RNAPII influences nucleolar structure and function. We describe how RNAPII-dependent lncRNA can both promote nucleolar integrity and inhibit ribosomal (r)RNA synthesis by modulating the availability of rRNA synthesis factors in trans. Surprisingly, some lncRNA transcripts can directly originate from nucleolar loci and function in cis. The nucleolar intergenic spacer (IGS), for example, encodes nucleolar transcripts that counteract spurious rRNA synthesis in unperturbed cells. In response to DNA damage, RNAPII-dependent lncRNA originates directly at broken ribosomal (r)DNA loci and is processed into small ncRNA, possibly to modulate DNA repair. Thus, lncRNA-mediated regulation of nucleolar biology occurs by several modes of action and is more direct than anticipated, pointing to an intimate crosstalk of RNA metabolic events.
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8
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Štětková M, Growková K, Fojtík P, Valčíková B, Palušová V, Verlande A, Jorda R, Kryštof V, Hejret V, Alexiou P, Rotrekl V, Uldrijan S. CDK9 activity is critical for maintaining MDM4 overexpression in tumor cells. Cell Death Dis 2020; 11:754. [PMID: 32934219 PMCID: PMC7494941 DOI: 10.1038/s41419-020-02971-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 08/19/2020] [Accepted: 08/27/2020] [Indexed: 12/31/2022]
Abstract
The identification of the essential role of cyclin-dependent kinases (CDKs) in the control of cell division has prompted the development of small-molecule CDK inhibitors as anticancer drugs. For many of these compounds, the precise mechanism of action in individual tumor types remains unclear as they simultaneously target different classes of CDKs - enzymes controlling the cell cycle progression as well as CDKs involved in the regulation of transcription. CDK inhibitors are also capable of activating p53 tumor suppressor in tumor cells retaining wild-type p53 gene by modulating MDM2 levels and activity. In the current study, we link, for the first time, CDK activity to the overexpression of the MDM4 (MDMX) oncogene in cancer cells. Small-molecule drugs targeting the CDK9 kinase, dinaciclib, flavopiridol, roscovitine, AT-7519, SNS-032, and DRB, diminished MDM4 levels and activated p53 in A375 melanoma and MCF7 breast carcinoma cells with only a limited effect on MDM2. These results suggest that MDM4, rather than MDM2, could be the primary transcriptional target of pharmacological CDK inhibitors in the p53 pathway. CDK9 inhibitor atuveciclib downregulated MDM4 and enhanced p53 activity induced by nutlin-3a, an inhibitor of p53-MDM2 interaction, and synergized with nutlin-3a in killing A375 melanoma cells. Furthermore, we found that human pluripotent stem cell lines express significant levels of MDM4, which are also maintained by CDK9 activity. In summary, we show that CDK9 activity is essential for the maintenance of high levels of MDM4 in human cells, and drugs targeting CDK9 might restore p53 tumor suppressor function in malignancies overexpressing MDM4.
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Affiliation(s)
- Monika Štětková
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Kateřina Growková
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Petr Fojtík
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic
| | - Barbora Valčíková
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic
| | - Veronika Palušová
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic
| | - Amandine Verlande
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic
| | - Radek Jorda
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, The Czech Academy of Sciences, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacký University, Hněvotínská 5, 779 00, Olomouc, Czech Republic
| | - Vladimír Kryštof
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, The Czech Academy of Sciences, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacký University, Hněvotínská 5, 779 00, Olomouc, Czech Republic
| | - Václav Hejret
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Panagiotis Alexiou
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Vladimír Rotrekl
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic
| | - Stjepan Uldrijan
- Faculty of Medicine, Department of Biology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
- International Clinical Research Center, St. Anne's University Hospital, Pekařská 53, 656 91, Brno, Czech Republic.
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9
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Abraham KJ, Khosraviani N, Chan JNY, Gorthi A, Samman A, Zhao DY, Wang M, Bokros M, Vidya E, Ostrowski LA, Oshidari R, Pietrobon V, Patel PS, Algouneh A, Singhania R, Liu Y, Yerlici VT, De Carvalho DD, Ohh M, Dickson BC, Hakem R, Greenblatt JF, Lee S, Bishop AJR, Mekhail K. Nucleolar RNA polymerase II drives ribosome biogenesis. Nature 2020; 585:298-302. [PMID: 32669707 PMCID: PMC7486236 DOI: 10.1038/s41586-020-2497-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/21/2020] [Indexed: 12/16/2022]
Abstract
Proteins are manufactured by ribosomes-macromolecular complexes of protein and RNA molecules that are assembled within major nuclear compartments called nucleoli1,2. Existing models suggest that RNA polymerases I and III (Pol I and Pol III) are the only enzymes that directly mediate the expression of the ribosomal RNA (rRNA) components of ribosomes. Here we show, however, that RNA polymerase II (Pol II) inside human nucleoli operates near genes encoding rRNAs to drive their expression. Pol II, assisted by the neurodegeneration-associated enzyme senataxin, generates a shield comprising triplex nucleic acid structures known as R-loops at intergenic spacers flanking nucleolar rRNA genes. The shield prevents Pol I from producing sense intergenic noncoding RNAs (sincRNAs) that can disrupt nucleolar organization and rRNA expression. These disruptive sincRNAs can be unleashed by Pol II inhibition, senataxin loss, Ewing sarcoma or locus-associated R-loop repression through an experimental system involving the proteins RNaseH1, eGFP and dCas9 (which we refer to as 'red laser'). We reveal a nucleolar Pol-II-dependent mechanism that drives ribosome biogenesis, identify disease-associated disruption of nucleoli by noncoding RNAs, and establish locus-targeted R-loop modulation. Our findings revise theories of labour division between the major RNA polymerases, and identify nucleolar Pol II as a major factor in protein synthesis and nuclear organization, with potential implications for health and disease.
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Affiliation(s)
- Karan J Abraham
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Negin Khosraviani
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Janet N Y Chan
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Aparna Gorthi
- Greehey Children's Cancer Research Institute, Department of Cell Systems and Anatomy, University of Texas Health at San Antonio, San Antonio, TX, USA
| | - Anas Samman
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Dorothy Y Zhao
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Miling Wang
- Sylvester Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Michael Bokros
- Sylvester Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Elva Vidya
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Lauren A Ostrowski
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Roxanne Oshidari
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Violena Pietrobon
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Parasvi S Patel
- Princess Margaret Cancer Research Centre, University Health Network, and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Arash Algouneh
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Princess Margaret Cancer Research Centre, University Health Network, and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Rajat Singhania
- Princess Margaret Cancer Research Centre, University Health Network, and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Yupeng Liu
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - V Talya Yerlici
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Daniel D De Carvalho
- Princess Margaret Cancer Research Centre, University Health Network, and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Michael Ohh
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Brendan C Dickson
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Razq Hakem
- Princess Margaret Cancer Research Centre, University Health Network, and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Jack F Greenblatt
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Stephen Lee
- Sylvester Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Alexander J R Bishop
- Greehey Children's Cancer Research Institute, Department of Cell Systems and Anatomy, University of Texas Health at San Antonio, San Antonio, TX, USA
- Mays Cancer Center, University of Texas Health at San Antonio, San Antonio, TX, USA
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
- Canada Research Chairs Program, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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10
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El Hassouni B, Sarkisjan D, Vos JC, Giovannetti E, Peters GJ. Targeting the Ribosome Biogenesis Key Molecule Fibrillarin to Avoid Chemoresistance. Curr Med Chem 2019; 26:6020-6032. [PMID: 30501594 DOI: 10.2174/0929867326666181203133332] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 11/07/2018] [Accepted: 11/07/2018] [Indexed: 12/22/2022]
Abstract
Background:
Inherent or acquired chemo resistance in cancer patients has been a perpetual
limitation in cancer treatment. Expanding knowledge on essential cellular processes opens a new
window for therapeutic targeting. Ribosome biogenesis is a process that shows potential due to its
fundamental role in cell development and contribution to tumorigenesis as a result of its upregulation.
Inhibiting components of ribosome biogenesis has been explored and has shown interesting
results. Yet, an important key component, methyltransferase Fibrillarin (FBL), which influences
both the abundance and composition of ribosomes, has not been exploited thus far.
Methods:
In this literature review, we describe relevant aspects of ribosome biogenesis in cancer to
emphasize the potential of FBL as a therapeutic target, in order to lower the genotoxic effects of
anti-cancer treatment.
Results:
Remarkably, the amplification of the 19q13 cytogenetic band, including the gene coding
for FBL, correlated to cell viability and resistance in pancreatic cells as well as to a trend toward a
shorter survival in pancreatic cancer patients.
:
Targeting ribosome biogenesis, more specifically compared to the secondary effects of chemotherapeutics
such as 5-fluorouracil or oxaliplatin, has been achieved by compound CX-5461. The cell
dependent activity of this Pol I inhibitor has been reported in ovarian cancer, melanoma and leukemia
models with active or mutated p53 status, presenting a promising mechanism to evade p53 resistance.
Conclusion:
Targeting critical ribosome biogenesis components in order to decrease the genotoxic
activity in cancer cell looks promising. Hence, we believe that targeting key protein rRNA methyltransferase
FBL shows great potential, due to its pivotal role in ribosome biogenesis, its correlation
to an improved survival rate at low expression in breast cancer patients and its association with p53.
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Affiliation(s)
- Btissame El Hassouni
- Department of Medical Oncology, VU University Medical Center- Cancer Center Amsterdam, De Boelelaan 1118, 1081 HV Amsterdam, Netherlands
| | - Dzjemma Sarkisjan
- Department of Medical Oncology, VU University Medical Center- Cancer Center Amsterdam, De Boelelaan 1118, 1081 HV Amsterdam, Netherlands
| | - J. Chris Vos
- AIMMS-Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University Amsterdam, O
- 2 building, De Boelelaan 1108, 1081 HZ Amsterdam, Netherlands
| | - Elisa Giovannetti
- Department of Medical Oncology, VU University Medical Center- Cancer Center Amsterdam, De Boelelaan 1118, 1081 HV Amsterdam, Netherlands
| | - Godefridus J. Peters
- Department of Medical Oncology, VU University Medical Center- Cancer Center Amsterdam, De Boelelaan 1118, 1081 HV Amsterdam, Netherlands
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11
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Tokunaga M, Miyamoto Y, Suzuki T, Otani M, Inuki S, Esaki T, Nagao C, Mizuguchi K, Ohno H, Yoneda Y, Okamoto T, Oka M, Matsuura Y. Novel anti-flavivirus drugs targeting the nucleolar distribution of core protein. Virology 2019; 541:41-51. [PMID: 31826845 DOI: 10.1016/j.virol.2019.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 11/27/2019] [Accepted: 11/27/2019] [Indexed: 01/04/2023]
Abstract
The risk of infectious diseases caused by Flavivirus is increasing globally. Here, we developed a novel high-throughput screening (HTS) system to evaluate the inhibitory effects of compounds targeting the nuclear localization of the flavivirus core protein. We screened 4000 compounds based on their ability to inhibit the nuclear localization of the core protein, and identified over 20 compounds including inhibitors for cyclin dependent kinase and glycogen synthase kinase. The efficacy of the identified compounds to suppress viral growth was validated in a cell-based infection system. Remarkably, the nucleolus morphology was affected by the treatment with the compounds, suggesting that the nucleolus function is critical for viral propagation. The present HTS system provides a useful strategy for the identification of antivirals against flavivirus by targeting the nucleolar localization of the core protein.
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Affiliation(s)
- Makoto Tokunaga
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yoichi Miyamoto
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Tatsuya Suzuki
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Mayumi Otani
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Shinsuke Inuki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Tsuyoshi Esaki
- Laboratory of Bioinformatics, Artificial Intelligence Center for Health and Biomedical Research, National Institute of Biomedical Innovation, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan; Center for Data Science Education and Research, Shiga University, Shiga, Japan
| | - Chioko Nagao
- Laboratory of In-silico Drug Design, Center for Drug Design Research, National Institute of Biomedical Innovation, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Kenji Mizuguchi
- Laboratory of Bioinformatics, Artificial Intelligence Center for Health and Biomedical Research, National Institute of Biomedical Innovation, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan; Laboratory of In-silico Drug Design, Center for Drug Design Research, National Institute of Biomedical Innovation, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan; Institute for Protein Research, Osaka University, Osaka, Japan
| | - Hiroaki Ohno
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yoshihiro Yoneda
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Toru Okamoto
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
| | - Masahiro Oka
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan.
| | - Yoshiharu Matsuura
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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Carotenuto P, Pecoraro A, Palma G, Russo G, Russo A. Therapeutic Approaches Targeting Nucleolus in Cancer. Cells 2019; 8:E1090. [PMID: 31527430 PMCID: PMC6770360 DOI: 10.3390/cells8091090] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/08/2019] [Accepted: 09/13/2019] [Indexed: 01/08/2023] Open
Abstract
The nucleolus is a distinct sub-cellular compartment structure in the nucleus. First observed more than 200 years ago, the nucleolus is detectable by microscopy in eukaryotic cells and visible during the interphase as a sub-nuclear structure immersed in the nucleoplasm, from which it is not separated from any membrane. A huge number of studies, spanning over a century, have identified ribosome biogenesis as the main function of the nucleolus. Recently, novel functions, independent from ribosome biogenesis, have been proposed by several proteomic, genomic, and functional studies. Several works have confirmed the non-canonical role for nucleoli in regulating important cellular processes including genome stability, cell-cycle control, the cellular senescence, stress responses, and biogenesis of ribonucleoprotein particles (RNPs). Many authors have shown that both canonical and non-canonical functions of the nucleolus are associated with several cancer-related processes. The association between the nucleolus and cancer, first proposed by cytological and histopathological studies showing that the number and shape of nucleoli are commonly altered in almost any type of cancer, has been confirmed at the molecular level by several authors who demonstrated that numerous mechanisms occurring in the nucleolus are altered in tumors. Recently, therapeutic approaches targeting the nucleolus in cancer have started to be considered as an emerging "hallmark" of cancer and several therapeutic interventions have been developed. This review proposes an up-to-date overview of available strategies targeting the nucleolus, focusing on novel targeted therapeutic approaches. Finally, a target-based classification of currently available treatment will be proposed.
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Affiliation(s)
- Pietro Carotenuto
- The Institute of Cancer Research, Cancer Therapeutic Unit, London SM2 5NG, UK.
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli 80078, Italy.
| | - Annalisa Pecoraro
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano 49, 80131 Naples, Italy.
| | - Gaetano Palma
- Department of Advanced Biomedical Science, School of Medicine, University of Naples Federico II, 80131 Naples, Italy.
| | - Giulia Russo
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano 49, 80131 Naples, Italy.
| | - Annapina Russo
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano 49, 80131 Naples, Italy.
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Transcription Repressor Hes1 Contributes to Neuropathic Pain Development by Modifying CDK9/RNAPII-Dependent Spinal mGluR5 Transcription. Int J Mol Sci 2019; 20:ijms20174177. [PMID: 31454988 PMCID: PMC6747068 DOI: 10.3390/ijms20174177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/23/2019] [Accepted: 08/25/2019] [Indexed: 11/18/2022] Open
Abstract
Diverse transcriptional controls in the dorsal horn have been observed in pain hypersensitivity. However, the understanding of the exact causes and mechanisms of neuropathic pain development is still fragmentary. Here, the results demonstrated nerve injury decreased the expression of spinal hairy and enhancer of split 1 (Hes1), a transcriptional repressor, and enhanced metabotropic glutamate receptor subtype 5 (mGluR5) transcription/expression, which was accompanied with behavioral allodynia. Moreover, nerve injury decreased Hes1 levels and reciprocally increased cyclin dependent kinase-9 (CDK9) levels and recruited CDK9 to phosphorylate RNA polymerase II (RNAPII) in the promoter fragments of mGluR5, thereby enhancing mGluR5 transcription/expression in the dorsal horn. These effects were also induced by intrathecally administering naïve rats with Hes1 small interfering RNA (siRNA). Conversely, Hes1 overexpression using intrathecal lentiviral vectors in nerve injury rats produced reversal of pain behavior and reversed protein expressions, phosphorylation, and coupling to the promoter segments in the dorsal horn. Collectively, the results in this study indicated nerve injury diminishes spinal Hes1-dependent suppression of CDK9-dependent RNAPII phosphorylation on the mGluR5 promoter that possibly enhances mGluR5 transcription/expression for neuropathic pain development.
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Abstract
A complex network precisely regulates the cell cycle through the G1, S, G2, and M phases and is the basis for cell division under physiological and pathological conditions. On the one hand, the transition from one phase to another as well as the progression within each phase is driven by the specific cyclin-dependent kinases (CDKs; e.g., CDK1, CDK2, CDK4, CDK6, and CDK7), together with their exclusive partner cyclins (e.g., cyclin A1, B1, D1–3, and E1). On the other hand, these phases are negatively regulated by endogenous CDK inhibitors such as p16ink4a, p18ink4c, p19ink4d, p21cip1, and p27kip1. In addition, several checkpoints control the commitment of cells to replicate DNA and undergo mitosis, thereby avoiding the passage of genomic errors to daughter cells. CDKs are often constitutively activated in cancer, which is characterized by the uncontrolled proliferation of transformed cells, due to genetic and epigenetic abnormalities in the genes involved in the cell cycle. Moreover, several oncogenes and defective tumor suppressors promote malignant changes by stimulating cell cycle entry and progression or disrupting DNA damage responses, including the cell cycle checkpoints, DNA repair mechanisms, and apoptosis. Thus, genes or proteins related to cell cycle regulation remain the main targets of interest in the treatment of various cancer types, including hematologic malignancies. In this context, advances in the understanding of the cell cycle regulatory machinery provide a basis for the development of novel therapeutic approaches. The present article summarizes the pathways as well as their genetic and epigenetic alterations that regulate the cell cycle; moreover, it discusses the various approved or potential therapeutic targets associated with the cell cycle, focusing on hematologic malignancies.
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15
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Molecular mechanisms of Dicer: endonuclease and enzymatic activity. Biochem J 2017; 474:1603-1618. [PMID: 28473628 PMCID: PMC5415849 DOI: 10.1042/bcj20160759] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 12/12/2022]
Abstract
The enzyme Dicer is best known for its role as a riboendonuclease in the small RNA pathway. In this canonical role, Dicer is a critical regulator of the biogenesis of microRNA and small interfering RNA, as well as a growing number of additional small RNAs derived from various sources. Emerging evidence demonstrates that Dicer's endonuclease role extends beyond the generation of small RNAs; it is also involved in processing additional endogenous and exogenous substrates, and is becoming increasingly implicated in regulating a variety of other cellular processes, outside of its endonuclease function. This review will describe the canonical and newly identified functions of Dicer.
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16
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Oqani RK, Lin T, Lee JE, Kim SY, Sa SJ, Woo JS, Jin DI. Inhibition of P-TEFb disrupts global transcription, oocyte maturation, and embryo development in the mouse. Genesis 2016; 54:470-82. [PMID: 27488304 DOI: 10.1002/dvg.22961] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/30/2016] [Accepted: 08/01/2016] [Indexed: 11/11/2022]
Abstract
Positive transcription elongation factor b (P-TEFb) is an RNA polymerase II kinase that phosphorylates Ser2 of the carboxyl-terminal domain and promotes the elongation phase of transcription. Despite the fact that P-TEFb has role in many cellular processes, the role of this kinase complex remains to be understood in early developmental events. In this study, using immunocytochemical analyses, we find that the P-TEFb components, Cyclin T1, CDK9, and its T-loop phosphorylated form, are localized to nuclear speckles, as well as in nucleoli in mouse germinal vesicle oocytes. Moreover, using fluorescence in situ hybridization, we show that in absence of CDK9 activity, nucleolar integration, as well as production of 28S rRNA is impaired in oocytes and embryos. We also present evidence indicating that P-TEFb kinase activity is essential for completion of mouse oocyte maturation and embryo development. Treatment with CDK9 inhibitor, flavopiridol resulted in metaphase I arrest in maturing oocytes. Inhibition of CDK9 kinase activity did not interfere with in vitro fertilization and pronuclear formation. However, when zygotes or 2-cell embryos were treated with flavopiridol only in their G2 phase of the cell cycle, development to the blastocyst stage was impaired. Inhibition of the CDK9 activity after embryonic genome activation resulted in failure to form normal blastocysts and aberrant phosphorylation of RNA polymerase II CTD. In all stages analyzed, treatment with flavopiridol abrogated global transcriptional activity. Collectively, our data suggest that P-TEFb kinase activity is crucial for oocyte maturation, embryo development, and regulation of global RNA transcription in mouse early development.
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Affiliation(s)
- Reza K Oqani
- Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Tao Lin
- Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Jae Eun Lee
- Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - So Yeon Kim
- Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Soo Jin Sa
- Department of Animal Resource Development, National Institute of Animal Science, Cheonan, 31001, Korea
| | - Je Seok Woo
- Department of Animal Resource Development, National Institute of Animal Science, Cheonan, 31001, Korea
| | - Dong Il Jin
- Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, 34134, Republic of Korea.
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P-TEFb Kinase Activity Is Essential for Global Transcription, Resumption of Meiosis and Embryonic Genome Activation in Pig. PLoS One 2016; 11:e0152254. [PMID: 27011207 PMCID: PMC4807088 DOI: 10.1371/journal.pone.0152254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/13/2016] [Indexed: 11/20/2022] Open
Abstract
Positive transcription elongation factor b (P-TEFb) is a RNA polymerase II carboxyl-terminal domain (Pol II CTD) kinase that phosphorylates Ser2 of the CTD and promotes the elongation phase of transcription. Despite the fact that P-TEFb has role in many cellular processes, the role of this kinase complex remains to be understood in mammalian early developmental events. In this study, using immunocytochemical analyses, we found that the P-TEFb components, CDK9, Cyclin T1 and Cyclin T2 were localized to nuclear speckles, as well as in nucleolar-like bodies in pig germinal vesicle oocytes. Using nascent RNA labeling and small molecule inhibitors, we showed that inhibition of CDK9 activity abolished the transcription of GV oocytes globally. Moreover, using fluorescence in situ hybridization, in absence of CDK9 kinase activity the production of ribosomal RNAs was impaired. We also presented the evidences indicating that P-TEFb kinase activity is essential for resumption of oocyte meiosis and embryo development. Treatment with CDK9 inhibitors resulted in germinal vesicle arrest in maturing oocytes in vitro. Inhibition of CDK9 kinase activity did not interfere with in vitro fertilization and pronuclear formation. However, when in vitro produced zygotes were treated with CDK9 inhibitors, their development beyond the 4-cell stage was impaired. In these embryos, inhibition of CDK9 abrogated global transcriptional activity and rRNA production. Collectively, our data suggested that P-TEFb kinase activity is crucial for oocyte maturation, embryo development and regulation of RNA transcription in pig.
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Burger K, Eick D. A Nonradioactive Assay to Measure Production and Processing of Ribosomal RNA by 4sU-Tagging. Methods Mol Biol 2016; 1455:121-31. [PMID: 27576715 DOI: 10.1007/978-1-4939-3792-9_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In vivo metabolic pulse labeling is a classical approach to assess production and processing of ribosomal RNA (rRNA). However, conventional labeling techniques can be indirect and require work with radioactivity. Here, we describe in detail a protocol for in vivo metabolic labeling, purification, and readout of nascent rRNA by 4-thiouridine (4sU). We propose 4sU labeling as standard nonradioactive technique for the analysis of rRNA metabolism during ribosome biogenesis.
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Affiliation(s)
- Kaspar Burger
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, Oxford, UK
| | - Dirk Eick
- Department of Molecular Epigenetics, Helmholtz Center Munich and Center for Integrated Protein Science Munich (CIPSM), Marchioninistrasse 25, 81377, Munich, Germany.
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19
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Burger K, Gullerova M. Swiss army knives: non-canonical functions of nuclear Drosha and Dicer. Nat Rev Mol Cell Biol 2015; 16:417-30. [DOI: 10.1038/nrm3994] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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20
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Kellner M, Rohrmoser M, Forné I, Voss K, Burger K, Mühl B, Gruber-Eber A, Kremmer E, Imhof A, Eick D. DEAD-box helicase DDX27 regulates 3' end formation of ribosomal 47S RNA and stably associates with the PeBoW-complex. Exp Cell Res 2015; 334:146-59. [PMID: 25825154 DOI: 10.1016/j.yexcr.2015.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 02/07/2023]
Abstract
PeBoW, a trimeric complex consisting of pescadillo (Pes1), block of proliferation (Bop1), and the WD repeat protein 12 (WDR12), is essential for processing and maturation of mammalian 5.8S and 28S ribosomal RNAs. Applying a mass spectrometric analysis, we identified the DEAD-box helicase DDX27 as stably associated factor of the PeBoW-complex. DDX27 interacts with the PeBoW-complex via an evolutionary conserved F×F motif in the N-terminal domain and is recruited to the nucleolus via its basic C-terminal domain. This recruitment is RNA-dependent and occurs independently of the PeBoW-complex. Interestingly, knockdown of DDX27, but not of Pes1, induces the accumulation of an extended form of the primary 47S rRNA. We conclude that DDX27 can interact specifically with the Pes1 and Bop1 but fulfils critical function(s) for proper 3' end formation of 47S rRNA independently of the PeBoW-complex.
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Affiliation(s)
- Markus Kellner
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Michaela Rohrmoser
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Ignasi Forné
- Adolf Butenandt Institute, Ludwig Maximilians University of Munich, Center for Integrated Protein Science Munich (CIPSM), Schillerstr. 44, Munich 80336, Germany
| | - Kirsten Voss
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Kaspar Burger
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Bastian Mühl
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Anita Gruber-Eber
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, Helmholtz Center Munich, Marchioninistr. 25, Munich 81377, Germany
| | - Axel Imhof
- Adolf Butenandt Institute, Ludwig Maximilians University of Munich, Center for Integrated Protein Science Munich (CIPSM), Schillerstr. 44, Munich 80336, Germany
| | - Dirk Eick
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany.
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21
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Clinical study of the novel cyclin-dependent kinase inhibitor dinaciclib in combination with rituximab in relapsed/refractory chronic lymphocytic leukemia patients. Cancer Chemother Pharmacol 2014; 74:1057-64. [PMID: 25217392 DOI: 10.1007/s00280-014-2583-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 08/30/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE Dinaciclib is a novel selective inhibitor of cyclin-dependent kinase (CDK)1, CDK2, CDK5, and CDK9. We conducted a phase I study to investigate the effects of dinaciclib when administered with rituximab. METHODS In this phase I nonrandomized dose-escalation 3 + 3 trial, patients with relapsed/refractory chronic lymphocytic leukemia (CLL) were treated with dinaciclib and rituximab. Dinaciclib was administered intravenously (IV) over 2 h on days 1, 8 and 15 in cycles 2-13 (28-day cycles). Rituximab 375 mg/m(2) was administered IV on days 1, 8, 15 and 22 in cycle 1 (28-day cycle) and on day 1 during cycle 3-13. Rituximab was not administered in cycle 2. Rituximab and dinaciclib were given alone in cycles 1 and 2, respectively, and in combination in cycles 3-13. Primary objectives included determination of the recommended phase II dose of dinaciclib and evaluation of pharmacokinetics (PK) when administered with rituximab. RESULTS Five patients completed the study due to early termination. All presented with drug-related adverse events (AEs), but no dose-limiting toxicities were observed. The most commonly observed toxicities included hematological, digestive and metabolic AEs. However, no tumor lysis syndrome has been reported in the study. Four patients achieved stable disease, and one patient achieved complete response according to 2008 iwCLL criteria at cycle 3. PK samples were collected from 5 patients, and no obvious interaction between dinaciclib and rituximab was observed. CONCLUSIONS Limited data from this study shows dinaciclib in combination with rituximab was well tolerated and revealed encouraging clinical activity in relapsed/refractory CLL patients.
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22
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Thomson E, Ferreira-Cerca S, Hurt E. Eukaryotic ribosome biogenesis at a glance. J Cell Sci 2014; 126:4815-21. [PMID: 24172536 DOI: 10.1242/jcs.111948] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ribosomes play a pivotal role in the molecular life of every cell. Moreover, synthesis of ribosomes is one of the most energetically demanding of all cellular processes. In eukaryotic cells, ribosome biogenesis requires the coordinated activity of all three RNA polymerases and the orchestrated work of many (>200) transiently associated ribosome assembly factors. The biogenesis of ribosomes is a tightly regulated activity and it is inextricably linked to other fundamental cellular processes, including growth and cell division. Furthermore, recent studies have demonstrated that defects in ribosome biogenesis are associated with several hereditary diseases. In this Cell Science at a Glance article and the accompanying poster, we summarise the current knowledge on eukaryotic ribosome biogenesis, with an emphasis on the yeast model system.
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Affiliation(s)
- Emma Thomson
- Biochemistry Center (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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23
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Cross-talk of phosphorylation and prolyl isomerization of the C-terminal domain of RNA Polymerase II. Molecules 2014; 19:1481-511. [PMID: 24473209 PMCID: PMC4350670 DOI: 10.3390/molecules19021481] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 01/06/2014] [Accepted: 01/21/2014] [Indexed: 12/04/2022] Open
Abstract
Post-translational modifications of the heptad repeat sequences in the C-terminal domain (CTD) of RNA polymerase II (Pol II) are well recognized for their roles in coordinating transcription with other nuclear processes that impinge upon transcription by the Pol II machinery; and this is primarily achieved through CTD interactions with the various nuclear factors. The identification of novel modifications on new regulatory sites of the CTD suggests that, instead of an independent action for all modifications on CTD, a combinatorial effect is in operation. In this review we focus on two well-characterized modifications of the CTD, namely serine phosphorylation and prolyl isomerization, and discuss the complex interplay between the enzymes modifying their respective regulatory sites. We summarize the current understanding of how the prolyl isomerization state of the CTD dictates the specificity of writers (CTD kinases), erasers (CTD phosphatases) and readers (CTD binding proteins) and how that correlates to transcription status. Subtle changes in prolyl isomerization states cannot be detected at the primary sequence level, we describe the methods that have been utilized to investigate this mode of regulation. Finally, a general model of how prolyl isomerization regulates the phosphorylation state of CTD, and therefore transcription-coupled processes, is proposed.
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24
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Quin JE, Devlin JR, Cameron D, Hannan KM, Pearson RB, Hannan RD. Targeting the nucleolus for cancer intervention. Biochim Biophys Acta Mol Basis Dis 2014; 1842:802-16. [PMID: 24389329 DOI: 10.1016/j.bbadis.2013.12.009] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/17/2013] [Indexed: 12/17/2022]
Abstract
The contribution of the nucleolus to cancer is well established with respect to its traditional role in facilitating ribosome biogenesis and proliferative capacity. More contemporary studies however, infer that nucleoli contribute a much broader role in malignant transformation. Specifically, extra-ribosomal functions of the nucleolus position it as a central integrator of cellular proliferation and stress signaling, and are emerging as important mechanisms for modulating how oncogenes and tumor suppressors operate in normal and malignant cells. The dependence of certain tumor cells to co-opt nucleolar processes to maintain their cancer phenotypes has now clearly been demonstrated by the application of small molecule inhibitors of RNA Polymerase I to block ribosomal DNA transcription and disrupt nucleolar function (Bywater et al., 2012 [1]). These drugs, which selectively kill tumor cells in vivo while sparing normal cells, have now progressed to clinical trials. It is likely that we have only just begun to scratch the surface of the potential of the nucleolus as a new target for cancer therapy, with "suppression of nucleolar stress" representing an emerging "hallmark" of cancer. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.
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Affiliation(s)
- Jaclyn E Quin
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Jennifer R Devlin
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Donald Cameron
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Kate M Hannan
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Richard B Pearson
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Ross D Hannan
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia; School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia.
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25
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Burger K, Mühl B, Kellner M, Rohrmoser M, Gruber-Eber A, Windhager L, Friedel CC, Dölken L, Eick D. 4-thiouridine inhibits rRNA synthesis and causes a nucleolar stress response. RNA Biol 2013; 10:1623-30. [PMID: 24025460 DOI: 10.4161/rna.26214] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
High concentrations (> 100 µM) of the ribonucleoside analog 4-thiouridine (4sU) is widely used in methods for RNA analysis like photoactivatable-ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) and nascent messenger (m)RNA labeling (4sU-tagging). Here, we show that 4sU-tagging at low concentrations ≤ 10 µM can be used to measure production and processing of ribosomal (r)RNA. However, elevated concentrations of 4sU (> 50 µM), which are usually used for mRNA labeling experiments, inhibit production and processing of 47S rRNA. The inhibition of rRNA synthesis is accompanied by nucleoplasmic translocation of nucleolar nucleophosmin (NPM1), induction of the tumor suppressor p53, and inhibition of proliferation. We conclude that metabolic labeling of RNA by 4sU triggers a nucleolar stress response, which might influence the interpretation of results. Therefore, functional ribosome biogenesis, nucleolar integrity, and cell cycle should be addressed in 4sU labeling experiments.
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Affiliation(s)
- Kaspar Burger
- Department of Molecular Epigenetics; Helmholtz Center Munich; Center for Integrated Protein Science Munich (CIPSM); Munich, Germany
| | - Bastian Mühl
- Department of Molecular Epigenetics; Helmholtz Center Munich; Center for Integrated Protein Science Munich (CIPSM); Munich, Germany
| | - Markus Kellner
- Department of Molecular Epigenetics; Helmholtz Center Munich; Center for Integrated Protein Science Munich (CIPSM); Munich, Germany
| | - Michaela Rohrmoser
- Department of Molecular Epigenetics; Helmholtz Center Munich; Center for Integrated Protein Science Munich (CIPSM); Munich, Germany
| | - Anita Gruber-Eber
- Department of Molecular Epigenetics; Helmholtz Center Munich; Center for Integrated Protein Science Munich (CIPSM); Munich, Germany
| | - Lukas Windhager
- Institute for Informatics, Teaching and Research Unit Bioinformatics; Ludwig-Maximilians-University Munich; Munich, Germany
| | - Caroline C Friedel
- Institute for Informatics, Teaching and Research Unit Bioinformatics; Ludwig-Maximilians-University Munich; Munich, Germany
| | - Lars Dölken
- Department of Medicine; Addenbrooke's Hospital; University of Cambridge; Cambridge, UK
| | - Dirk Eick
- Department of Molecular Epigenetics; Helmholtz Center Munich; Center for Integrated Protein Science Munich (CIPSM); Munich, Germany
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