1
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Chen JJ, Moy C, Pagé V, Monnin C, El-Hajj ZW, Avizonis DZ, Reyes-Lamothe R, Tanny JC. The Rtf1/Prf1-dependent histone modification axis counteracts multi-drug resistance in fission yeast. Life Sci Alliance 2024; 7:e202302494. [PMID: 38514187 PMCID: PMC10958104 DOI: 10.26508/lsa.202302494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 03/23/2024] Open
Abstract
RNA polymerase II transcription elongation directs an intricate pattern of histone modifications. This pattern includes a regulatory cascade initiated by the elongation factor Rtf1, leading to monoubiquitylation of histone H2B, and subsequent methylation of histone H3 on lysine 4. Previous studies have defined the molecular basis for these regulatory relationships, but it remains unclear how they regulate gene expression. To address this question, we investigated a drug resistance phenotype that characterizes defects in this axis in the model eukaryote Schizosaccharomyces pombe (fission yeast). The mutations caused resistance to the ribonucleotide reductase inhibitor hydroxyurea (HU) that correlated with a reduced effect of HU on dNTP pools, reduced requirement for the S-phase checkpoint, and blunting of the transcriptional response to HU treatment. Mutations in the C-terminal repeat domain of the RNA polymerase II large subunit Rpb1 led to similar phenotypes. Moreover, all the HU-resistant mutants also exhibited resistance to several azole-class antifungal agents. Our results suggest a novel, shared gene regulatory function of the Rtf1-H2Bub1-H3K4me axis and the Rpb1 C-terminal repeat domain in controlling fungal drug tolerance.
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Affiliation(s)
- Jennifer J Chen
- https://ror.org/01pxwe438 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Calvin Moy
- https://ror.org/01pxwe438 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Viviane Pagé
- https://ror.org/01pxwe438 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Cian Monnin
- https://ror.org/01pxwe438 Metabolomics Innovation Resource, Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Ziad W El-Hajj
- https://ror.org/01pxwe438 Department of Biology, McGill University, Montreal, Canada
| | - Daina Z Avizonis
- https://ror.org/01pxwe438 Metabolomics Innovation Resource, Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Rodrigo Reyes-Lamothe
- https://ror.org/01pxwe438 Department of Biology, McGill University, Montreal, Canada
| | - Jason C Tanny
- https://ror.org/01pxwe438 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
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2
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del Dedo JE, Segundo RLS, Vázquez-Bolado A, Sun J, García-Blanco N, Suárez MB, García P, Tricquet P, Chen JS, Dedon PC, Gould KL, Hidalgo E, Hermand D, Moreno S. The Greatwall-Endosulfine-PP2A/B55 pathway controls entry into quiescence by promoting translation of Elongator-tuneable transcripts. RESEARCH SQUARE 2023:rs.3.rs-3616701. [PMID: 38105947 PMCID: PMC10723533 DOI: 10.21203/rs.3.rs-3616701/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Quiescent cells require a continuous supply of proteins to maintain protein homeostasis. In fission yeast, entry into quiescence is triggered by nitrogen stress, leading to the inactivation of TORC1 and the activation of TORC2. Here, we report that the Greatwall-Endosulfine-PPA/B55 pathway connects the downregulation of TORC1 with the upregulation of TORC2, resulting in the activation of Elongator-dependent tRNA modifications essential for sustaining the translation programme during entry into quiescence. This process promotes U34 and A37 tRNA modifications at the anticodon stem loop, enhancing translation efficiency and fidelity of mRNAs enriched for AAA versus AAG lysine codons. Notably, some of these mRNAs encode inhibitors of TORC1, activators of TORC2, tRNA modifiers, and proteins necessary for telomeric and subtelomeric functions. Therefore, we propose a novel mechanism by which cells respond to nitrogen stress at the level of translation, involving a coordinated interplay between the tRNA epitranscriptome and biased codon usage.
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Affiliation(s)
- Javier Encinar del Dedo
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
| | - Rafael López-San Segundo
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
| | - Alicia Vázquez-Bolado
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
| | - Jingjing Sun
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Natalia García-Blanco
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
| | - M. Belén Suárez
- Instituto de Biología Funcional y Genómica, University of Salamanca, CSIC, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, University of Salamanca, 37007 Salamanca, Spain
| | - Patricia García
- Instituto de Biología Funcional y Genómica, University of Salamanca, CSIC, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, University of Salamanca, 37007 Salamanca, Spain
| | - Pauline Tricquet
- URPHYM-GEMO, University of Namur, rue de Bruxelles, 61, Namur 5000, Belgium
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States
| | - Peter C. Dedon
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
- Department of Biological Engineering and Center for Environmental Health Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Damien Hermand
- URPHYM-GEMO, University of Namur, rue de Bruxelles, 61, Namur 5000, Belgium
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
- Lead contact
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3
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Prokakis E, Jansari S, Boshnakovska A, Wiese M, Kusch K, Kramm C, Dullin C, Rehling P, Glatzel M, Pantel K, Wikman H, Johnsen SA, Gallwas J, Wegwitz F. RNF40 epigenetically modulates glycolysis to support the aggressiveness of basal-like breast cancer. Cell Death Dis 2023; 14:641. [PMID: 37770435 PMCID: PMC10539310 DOI: 10.1038/s41419-023-06157-5] [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] [Received: 12/05/2022] [Revised: 09/06/2023] [Accepted: 09/15/2023] [Indexed: 09/30/2023]
Abstract
Triple-negative breast cancer (TNBC) is the most difficult breast cancer subtype to treat due to the lack of targeted therapies. Cancer stem cells (CSCs) are strongly enriched in TNBC lesions and are responsible for the rapid development of chemotherapy resistance and metastasis. Ubiquitin-based epigenetic circuits are heavily exploited by CSCs to regulate gene transcription and ultimately sustain their aggressive behavior. Therefore, therapeutic targeting of these ubiquitin-driven dependencies may reprogram the transcription of CSC and render them more sensitive to standard therapies. In this work, we identified the Ring Finger Protein 40 (RNF40) monoubiquitinating histone 2B at lysine 120 (H2Bub1) as an indispensable E3 ligase for sustaining the stem-cell-like features of the growing mammary gland. In addition, we found that the RNF40/H2Bub1-axis promotes the CSC properties and drug-tolerant state by supporting the glycolytic program and promoting pro-tumorigenic YAP1-signaling in TNBC. Collectively, this study unveils a novel tumor-supportive role of RNF40 and underpins its high therapeutic value to combat the malignant behavior of TNBC.
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Affiliation(s)
- Evangelos Prokakis
- Department of Gynecology and Obstetrics, University Medical Center Göttingen, Göttingen, Germany.
- Department of General, Visceral & Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany.
| | - Shaishavi Jansari
- Department of Gynecology and Obstetrics, University Medical Center Göttingen, Göttingen, Germany
| | - Angela Boshnakovska
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Maria Wiese
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Kathrin Kusch
- Institute for Auditory Neuroscience, Functional Auditory Genomics Group, University Medical Center Göttingen, Göttingen, Germany
| | - Christof Kramm
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Christian Dullin
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Klaus Pantel
- Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Harriet Wikman
- Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Steven A Johnsen
- Department of General, Visceral & Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
- The Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
| | - Julia Gallwas
- Department of Gynecology and Obstetrics, University Medical Center Göttingen, Göttingen, Germany
| | - Florian Wegwitz
- Department of Gynecology and Obstetrics, University Medical Center Göttingen, Göttingen, Germany.
- Department of General, Visceral & Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany.
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4
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Luan J, Vermunt MW, Syrett CM, Coté A, Tome JM, Zhang H, Huang A, Luppino JM, Keller CA, Giardine BM, Zhang S, Dunagin MC, Zhang Z, Joyce EF, Lis JT, Raj A, Hardison RC, Blobel GA. CTCF blocks antisense transcription initiation at divergent promoters. Nat Struct Mol Biol 2022; 29:1136-1144. [PMID: 36369346 DOI: 10.1101/2021.10.30.465508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/29/2022] [Indexed: 05/26/2023]
Abstract
Transcription at most promoters is divergent, initiating at closely spaced oppositely oriented core promoters to produce sense transcripts along with often unstable upstream antisense transcripts (uasTrx). How antisense transcription is regulated and to what extent it is coordinated with sense transcription is not well understood. Here, by combining acute degradation of the multi-functional transcription factor CTCF and nascent transcription measurements, we find that CTCF specifically suppresses antisense but not sense transcription at hundreds of divergent promoters. Primary transcript RNA-FISH shows that CTCF lowers burst fraction but not burst intensity of uasTrx and that co-bursting of sense and antisense transcripts is disfavored. Genome editing, chromatin conformation studies and high-resolution transcript mapping revealed that precisely positioned CTCF directly suppresses the initiation of uasTrx, in a manner independent of its architectural function. In sum, CTCF shapes the transcriptional landscape in part by suppressing upstream antisense transcription.
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Affiliation(s)
- Jing Luan
- Medical Scientist Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marit W Vermunt
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Camille M Syrett
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Clarion Healthcare, LLC, Boston, MA, USA
| | - Allison Coté
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Jacob M Tome
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Shape Therapeutics Inc, Seattle, WA, USA
| | - Haoyue Zhang
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, China
| | - Anran Huang
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Jennifer M Luppino
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Cheryl A Keller
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Belinda M Giardine
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Shiping Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Margaret C Dunagin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhe Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Eric F Joyce
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Arjun Raj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ross C Hardison
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Gerd A Blobel
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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5
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Chen JJ, Stermer D, Tanny JC. Decoding histone ubiquitylation. Front Cell Dev Biol 2022; 10:968398. [PMID: 36105353 PMCID: PMC9464978 DOI: 10.3389/fcell.2022.968398] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Histone ubiquitylation is a critical part of both active and repressed transcriptional states, and lies at the heart of DNA damage repair signaling. The histone residues targeted for ubiquitylation are often highly conserved through evolution, and extensive functional studies of the enzymes that catalyze the ubiquitylation and de-ubiquitylation of histones have revealed key roles linked to cell growth and division, development, and disease in model systems ranging from yeast to human cells. Nonetheless, the downstream consequences of these modifications have only recently begun to be appreciated on a molecular level. Here we review the structure and function of proteins that act as effectors or “readers” of histone ubiquitylation. We highlight lessons learned about how ubiquitin recognition lends specificity and function to intermolecular interactions in the context of transcription and DNA repair, as well as what this might mean for how we think about histone modifications more broadly.
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6
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Targeting cyclin-dependent kinase 9 in cancer therapy. Acta Pharmacol Sin 2022; 43:1633-1645. [PMID: 34811514 PMCID: PMC9253122 DOI: 10.1038/s41401-021-00796-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Cyclin-dependent kinase (CDK) 9 associates mainly with cyclin T1 and forms the positive transcription elongation factor b (p-TEFb) complex responsible for transcriptional regulation. It has been shown that CDK9 modulates the expression and activity of oncogenes, such as MYC and murine double minute 4 (MDM4), and it also plays an important role in development and/or maintenance of the malignant cell phenotype. Malfunction of CDK9 is frequently observed in numerous cancers. Recent studies have highlighted the function of CDK9 through a variety of mechanisms in cancers, including the formation of new complexes and epigenetic alterations. Due to the importance of CDK9 activation in cancer cells, CDK9 inhibitors have emerged as promising candidates for cancer therapy. Natural product-derived and chemically synthesized CDK9 inhibitors are being examined in preclinical and clinical research. In this review, we summarize the current knowledge on the role of CDK9 in transcriptional regulation, epigenetic regulation, and different cellular factor interactions, focusing on new advances. We show the importance of CDK9 in mediating tumorigenesis and tumor progression. Then, we provide an overview of some CDK9 inhibitors supported by multiple oncologic preclinical and clinical investigations. Finally, we discuss the perspective and challenge of CDK9 modulation in cancer.
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7
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Schoelz JM, Riddle NC. Functions of HP1 proteins in transcriptional regulation. Epigenetics Chromatin 2022; 15:14. [PMID: 35526078 PMCID: PMC9078007 DOI: 10.1186/s13072-022-00453-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/18/2022] [Indexed: 01/24/2023] Open
Abstract
In eukaryotes, DNA is packaged into chromatin, which presents significant barriers to transcription. Non-histone chromatin proteins such as the Heterochromatin Protein 1 (HP1) proteins are critical regulators of transcription, contributing to gene regulation through a variety of molecular mechanisms. HP1 proteins are highly conserved, and many eukaryotic genomes contain multiple HP1 genes. Given the presence of multiple HP1 family members within a genome, HP1 proteins can have unique as well as shared functions. Here, we review the mechanisms by which HP1 proteins contribute to the regulation of transcription. Focusing on the Drosophila melanogaster HP1 proteins, we examine the role of these proteins in regulating the transcription of genes, transposable elements, and piRNA clusters. In D. melanogaster, as in other species, HP1 proteins can act as transcriptional repressors and activators. The available data reveal that the precise impact of HP1 proteins on gene expression is highly context dependent, on the specific HP1 protein involved, on its protein partners present, and on the specific chromatin context the interaction occurs in. As a group, HP1 proteins utilize a variety of mechanisms to contribute to transcriptional regulation, including both transcriptional (i.e. chromatin-based) and post-transcriptional (i.e. RNA-based) processes. Despite extensive studies of this important protein family, open questions regarding their functions in gene regulation remain, specifically regarding the role of hetero- versus homodimerization and post-translational modifications of HP1 proteins.
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Affiliation(s)
- John M Schoelz
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicole C Riddle
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
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8
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Transcription and chromatin-based surveillance mechanism controls suppression of cryptic antisense transcription. Cell Rep 2021; 36:109671. [PMID: 34496258 PMCID: PMC8441049 DOI: 10.1016/j.celrep.2021.109671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 08/26/2020] [Accepted: 08/13/2021] [Indexed: 12/25/2022] Open
Abstract
Phosphorylation of the RNA polymerase II C-terminal domain Y1S2P3T4S5P6S7 consensus sequence coordinates key events during transcription, and its deregulation leads to defects in transcription and RNA processing. Here, we report that the histone deacetylase activity of the fission yeast Hos2/Set3 complex plays an important role in suppressing cryptic initiation of antisense transcription when RNA polymerase II phosphorylation is dysregulated due to the loss of Ssu72 phosphatase. Interestingly, although single Hos2 and Set3 mutants have little effect, loss of Hos2 or Set3 combined with ssu72Δ results in a synergistic increase in antisense transcription globally and correlates with elevated sensitivity to genotoxic agents. We demonstrate a key role for the Ssu72/Hos2/Set3 mechanism in the suppression of cryptic antisense transcription at the 3' end of convergent genes that are most susceptible to these defects, ensuring the fidelity of gene expression within dense genomes of simple eukaryotes.
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9
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Shirra MK, Kocik RA, Ellison MA, Arndt KM. Opposing functions of the Hda1 complex and histone H2B mono-ubiquitylation in regulating cryptic transcription in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2021; 11:6360461. [PMID: 34499735 PMCID: PMC8527469 DOI: 10.1093/g3journal/jkab298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022]
Abstract
Maintenance of chromatin structure under the disruptive force of transcription requires cooperation among numerous regulatory factors. Histone post-translational modifications can regulate nucleosome stability and influence the disassembly and reassembly of nucleosomes during transcription elongation. The Paf1 transcription elongation complex, Paf1C, is required for several transcription-coupled histone modifications, including the mono-ubiquitylation of H2B. In Saccharomyces cerevisiae, amino acid substitutions in the Rtf1 subunit of Paf1C greatly diminish H2B ubiquitylation and cause transcription to initiate at a cryptic promoter within the coding region of the FLO8 gene, an indicator of chromatin disruption. In a genetic screen to identify factors that functionally interact with Paf1C, we identified mutations in HDA3, a gene encoding a subunit of the Hda1C histone deacetylase (HDAC), as suppressors of an rtf1 mutation. Absence of Hda1C also suppresses the cryptic initiation phenotype of other mutants defective in H2B ubiquitylation. The genetic interactions between Hda1C and the H2B ubiquitylation pathway appear specific: loss of Hda1C does not suppress the cryptic initiation phenotypes of other chromatin mutants and absence of other HDACs does not suppress the absence of H2B ubiquitylation. Providing further support for an appropriate balance of histone acetylation in regulating cryptic initiation, absence of the Sas3 histone acetyltransferase elevates cryptic initiation in rtf1 mutants. Our data suggest that the H2B ubiquitylation pathway and Hda1C coordinately regulate chromatin structure during transcription elongation and point to a potential role for a HDAC in supporting chromatin accessibility.
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Affiliation(s)
- Margaret K Shirra
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Rachel A Kocik
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Mitchell A Ellison
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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10
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Venkat Ramani MK, Yang W, Irani S, Zhang Y. Simplicity is the Ultimate Sophistication-Crosstalk of Post-translational Modifications on the RNA Polymerase II. J Mol Biol 2021; 433:166912. [PMID: 33676925 PMCID: PMC8184622 DOI: 10.1016/j.jmb.2021.166912] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/23/2021] [Accepted: 02/26/2021] [Indexed: 12/19/2022]
Abstract
The highly conserved C-terminal domain (CTD) of the largest subunit of RNA polymerase II comprises a consensus heptad (Y1S2P3T4S5P6S7) repeated multiple times. Despite the simplicity of its sequence, the essential CTD domain orchestrates eukaryotic transcription and co-transcriptional processes, including transcription initiation, elongation, and termination, and mRNA processing. These distinct facets of the transcription cycle rely on specific post-translational modifications (PTM) of the CTD, in which five out of the seven residues in the heptad repeat are subject to phosphorylation. A hypothesis termed the "CTD code" has been proposed in which these PTMs and their combinations generate a sophisticated landscape for spatiotemporal recruitment of transcription regulators to Pol II. In this review, we summarize the recent experimental evidence understanding the biological role of the CTD, implicating a context-dependent theme that significantly enhances the ability of accurate transcription by RNA polymerase II. Furthermore, feedback communication between the CTD and histone modifications coordinates chromatin states with RNA polymerase II-mediated transcription, ensuring the effective and accurate conversion of information into cellular responses.
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Affiliation(s)
| | - Wanjie Yang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, United States
| | - Seema Irani
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, United States
| | - Yan Zhang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, United States; The Institute for Cellular and Molecular Biology. University of Texas at Austin, Austin, TX 78712, United States.
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11
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Pinto D, Pagé V, Fisher RP, Tanny JC. New connections between ubiquitylation and methylation in the co-transcriptional histone modification network. Curr Genet 2021; 67:695-705. [PMID: 34089069 DOI: 10.1007/s00294-021-01196-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/27/2021] [Accepted: 05/29/2021] [Indexed: 01/01/2023]
Abstract
Co-transcriptional histone modifications are a ubiquitous feature of RNA polymerase II (RNAPII) transcription, with profound but incompletely understood effects on gene expression. Unlike the covalent marks found at promoters, which are thought to be instructive for transcriptional activation, these modifications occur in gene bodies as a result of transcription, which has made elucidation of their functions challenging. Here we review recent insights into the regulation and roles of two such modifications: monoubiquitylation of histone H2B at lysine 120 (H2Bub1) and methylation of histone H3 at lysine 36 (H3K36me). Both H2Bub1 and H3K36me are enriched in the coding regions of transcribed genes, with highly overlapping distributions, but they were thought to work largely independently. We highlight our recent demonstration that, as was previously shown for H3K36me, H2Bub1 signals to the histone deacetylase (HDAC) complex Rpd3S/Clr6-CII, and that Rpd3S/Clr6-CII and H2Bub1 function in the same pathway to repress aberrant antisense transcription initiating within gene coding regions. Moreover, both of these histone modification pathways are influenced by protein phosphorylation catalyzed by the cyclin-dependent kinases (CDKs) that regulate RNAPII elongation, chiefly Cdk9. Therefore, H2Bub1 and H3K36me are more tightly linked than previously thought, sharing both upstream regulatory inputs and downstream effectors. Moreover, these newfound connections suggest extensive, bidirectional signaling between RNAPII elongation complexes and chromatin-modifying enzymes, which helps to determine transcriptional outputs and should be a focus for future investigation.
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Affiliation(s)
- Daniel Pinto
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Vivane Pagé
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Robert P Fisher
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Jason C Tanny
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
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12
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Cossa G, Parua PK, Eilers M, Fisher RP. Protein phosphatases in the RNAPII transcription cycle: erasers, sculptors, gatekeepers, and potential drug targets. Genes Dev 2021; 35:658-676. [PMID: 33888562 PMCID: PMC8091971 DOI: 10.1101/gad.348315.121] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In this review, Cossa et al. discuss the current knowledge and outstanding questions about phosphatases in the context of the RNAPII transcription cycle. The transcription cycle of RNA polymerase II (RNAPII) is governed at multiple points by opposing actions of cyclin-dependent kinases (CDKs) and protein phosphatases, in a process with similarities to the cell division cycle. While important roles of the kinases have been established, phosphatases have emerged more slowly as key players in transcription, and large gaps remain in understanding of their precise functions and targets. Much of the earlier work focused on the roles and regulation of sui generis and often atypical phosphatases—FCP1, Rtr1/RPAP2, and SSU72—with seemingly dedicated functions in RNAPII transcription. Decisive roles in the transcription cycle have now been uncovered for members of the major phosphoprotein phosphatase (PPP) family, including PP1, PP2A, and PP4—abundant enzymes with pleiotropic roles in cellular signaling pathways. These phosphatases appear to act principally at the transitions between transcription cycle phases, ensuring fine control of elongation and termination. Much is still unknown, however, about the division of labor among the PPP family members, and their possible regulation by or of the transcriptional kinases. CDKs active in transcription have recently drawn attention as potential therapeutic targets in cancer and other diseases, raising the prospect that the phosphatases might also present opportunities for new drug development. Here we review the current knowledge and outstanding questions about phosphatases in the context of the RNAPII transcription cycle.
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Affiliation(s)
- Giacomo Cossa
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Pabitra K Parua
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Martin Eilers
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Robert P Fisher
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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Marsh DJ, Ma Y, Dickson KA. Histone Monoubiquitination in Chromatin Remodelling: Focus on the Histone H2B Interactome and Cancer. Cancers (Basel) 2020; 12:E3462. [PMID: 33233707 PMCID: PMC7699835 DOI: 10.3390/cancers12113462] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 12/21/2022] Open
Abstract
Chromatin remodelling is a major mechanism by which cells control fundamental processes including gene expression, the DNA damage response (DDR) and ensuring the genomic plasticity required by stem cells to enable differentiation. The post-translational modification of histone H2B resulting in addition of a single ubiquitin, in humans at lysine 120 (K120; H2Bub1) and in yeast at K123, has key roles in transcriptional elongation associated with the RNA polymerase II-associated factor 1 complex (PAF1C) and in the DDR. H2Bub1 itself has been described as having tumour suppressive roles and a number of cancer-related proteins and/or complexes are recognised as part of the H2Bub1 interactome. These include the RING finger E3 ubiquitin ligases RNF20, RNF40 and BRCA1, the guardian of the genome p53, the PAF1C member CDC73, subunits of the switch/sucrose non-fermenting (SWI/SNF) chromatin remodelling complex and histone methyltransferase complexes DOT1L and COMPASS, as well as multiple deubiquitinases including USP22 and USP44. While globally depleted in many primary human malignancies, including breast, lung and colorectal cancer, H2Bub1 is selectively enriched at the coding region of certain highly expressed genes, including at p53 target genes in response to DNA damage, functioning to exercise transcriptional control of these loci. This review draws together extensive literature to cement a significant role for H2Bub1 in a range of human malignancies and discusses the interplay between key cancer-related proteins and H2Bub1-associated chromatin remodelling.
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Affiliation(s)
- Deborah J. Marsh
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (Y.M.); (K.-A.D.)
- Kolling Institute, Faculty of Medicine and Health, Northern Clinical School, University of Sydney, Camperdown, NSW 2006, Australia
| | - Yue Ma
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (Y.M.); (K.-A.D.)
| | - Kristie-Ann Dickson
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (Y.M.); (K.-A.D.)
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