1
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Kieft R, Zhang Y, Yan H, Schmitz RJ, Sabatini R. Protein phosphatase PP1 regulation of RNA polymerase II transcription termination and allelic exclusion of VSG genes in trypanosomes. Nucleic Acids Res 2024; 52:6866-6885. [PMID: 38783162 PMCID: PMC11229358 DOI: 10.1093/nar/gkae392] [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: 10/20/2023] [Revised: 04/19/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024] Open
Abstract
The genomes of Leishmania and trypanosomes are organized into polycistronic transcription units flanked by a modified DNA base J involved in promoting RNA polymerase II (Pol II) termination. We recently characterized a Leishmania complex containing a J-binding protein, PP1 protein phosphatase 1, and PP1 regulatory protein (PNUTS) that controls transcription termination potentially via dephosphorylation of Pol II by PP1. While T. brucei contains eight PP1 isoforms, none purified with the PNUTS complex, complicating the analysis of PP1 function in termination. We now demonstrate that the PP1-binding motif of TbPNUTS is required for function in termination in vivo and that TbPP1-1 modulates Pol II termination in T. brucei and dephosphorylation of the large subunit of Pol II. PP1-1 knock-down results in increased cellular levels of phosphorylated RPB1 accompanied by readthrough transcription and aberrant transcription of the chromosome by Pol II, including Pol I transcribed loci that are typically silent, such as telomeric VSG expression sites involved in antigenic variation. These results provide important insights into the mechanism underlying Pol II transcription termination in primitive eukaryotes that rely on polycistronic transcription and maintain allelic exclusion of VSG genes.
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Affiliation(s)
- Rudo Kieft
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Yang Zhang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Haidong Yan
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Robert Sabatini
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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2
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Kieft R, Reynolds D, Sabatini R. Epigenetic regulation of TERRA transcription and metacyclogenesis by base J in Leishmania major. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.27.601056. [PMID: 38979290 PMCID: PMC11230386 DOI: 10.1101/2024.06.27.601056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The hyper-modified DNA base J helps control termination of Pol II transcription at polycistronic transcription units (PTUs) in T. brucei and L. major , allowing epigenetic control of gene expression. The Telomere Repeat-containing RNA (TERRA) is synthesized in T. brucei by Pol I readthrough transcription of a telomeric PTU. While little is understood regarding TERRA synthesis and function, the hyper-modified DNA base J is highly enriched at telomeres in L. major promastigotes. We now show that TERRA is synthesized by Pol II in L. major and loss of base J leads to increased TERRA. For at least one site, the increased TERRA is by Pol II readthrough transcription from an adjacent PTU. Furthermore, Pol II readthrough defects and increased TERRA correlate with increased differentiation of promastigotes to the infectious metacyclic life stage and decreased cell viability. These results help explain the essential nature of base J in Leishmania and provide insight regarding epigenetic control of coding and non-coding RNA expression and parasite development during the life cycle of L. major .
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3
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Ni Z, Ahmed N, Nabeel-Shah S, Guo X, Pu S, Song J, Marcon E, Burke G, Tong AH, Chan K, Ha KH, Blencowe B, Moffat J, Greenblatt J. Identifying human pre-mRNA cleavage and polyadenylation factors by genome-wide CRISPR screens using a dual fluorescence readthrough reporter. Nucleic Acids Res 2024; 52:4483-4501. [PMID: 38587191 PMCID: PMC11077057 DOI: 10.1093/nar/gkae240] [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: 09/23/2023] [Revised: 01/29/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024] Open
Abstract
Messenger RNA precursors (pre-mRNA) generally undergo 3' end processing by cleavage and polyadenylation (CPA), which is specified by a polyadenylation site (PAS) and adjacent RNA sequences and regulated by a large variety of core and auxiliary CPA factors. To date, most of the human CPA factors have been discovered through biochemical and proteomic studies. However, genetic identification of the human CPA factors has been hampered by the lack of a reliable genome-wide screening method. We describe here a dual fluorescence readthrough reporter system with a PAS inserted between two fluorescent reporters. This system enables measurement of the efficiency of 3' end processing in living cells. Using this system in combination with a human genome-wide CRISPR/Cas9 library, we conducted a screen for CPA factors. The screens identified most components of the known core CPA complexes and other known CPA factors. The screens also identified CCNK/CDK12 as a potential core CPA factor, and RPRD1B as a CPA factor that binds RNA and regulates the release of RNA polymerase II at the 3' ends of genes. Thus, this dual fluorescence reporter coupled with CRISPR/Cas9 screens reliably identifies bona fide CPA factors and provides a platform for investigating the requirements for CPA in various contexts.
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Affiliation(s)
- Zuyao Ni
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Nujhat Ahmed
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
| | - Syed Nabeel-Shah
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
| | - Xinghua Guo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Shuye Pu
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Jingwen Song
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Edyta Marcon
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Giovanni L Burke
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
| | - Amy Hin Yan Tong
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON Canada
| | - Katherine Chan
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON Canada
| | - Kevin C H Ha
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
| | - Benjamin J Blencowe
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
| | - Jason Moffat
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON Canada
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON Canada
| | - Jack F Greenblatt
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5A 1A8, Canada
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4
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Lozano-Vidal N, Stanicek L, Bink DI, Juni RP, Hooglugt A, Kremer V, Phelp P, van Bergen A, MacInnes AW, Dimmeler S, Boon RA. Aging-regulated PNUTS maintains endothelial barrier function via SEMA3B suppression. Commun Biol 2024; 7:541. [PMID: 38714838 PMCID: PMC11076560 DOI: 10.1038/s42003-024-06230-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 04/22/2024] [Indexed: 05/12/2024] Open
Abstract
Age-related diseases pose great challenges to health care systems worldwide. During aging, endothelial senescence increases the risk for cardiovascular disease. Recently, it was described that Phosphatase 1 Nuclear Targeting Subunit (PNUTS) has a central role in cardiomyocyte aging and homeostasis. Here, we determine the role of PNUTS in endothelial cell aging. We confirm that PNUTS is repressed in senescent endothelial cells (ECs). Moreover, PNUTS silencing elicits several of the hallmarks of endothelial aging: senescence, reduced angiogenesis and loss of barrier function. Findings are validate in vivo using endothelial-specific inducible PNUTS-deficient mice (Cdh5-CreERT2;PNUTSfl/fl), termed PNUTSEC-KO. Two weeks after PNUTS deletion, PNUTSEC-KO mice present severe multiorgan failure and vascular leakage. Transcriptomic analysis of PNUTS-silenced HUVECs and lungs of PNUTSEC-KO mice reveal that the PNUTS-PP1 axis tightly regulates the expression of semaphorin 3B (SEMA3B). Indeed, silencing of SEMA3B completely restores barrier function after PNUTS loss-of-function. These results reveal a pivotal role for PNUTS in endothelial homeostasis through a SEMA3B downstream pathway that provides a potential target against the effects of aging in ECs.
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Affiliation(s)
- Noelia Lozano-Vidal
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Laura Stanicek
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
- Institute of Cardiovascular Regeneration, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Diewertje I Bink
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Rio P Juni
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Aukie Hooglugt
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Veerle Kremer
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Philippa Phelp
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Anke van Bergen
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Alyson W MacInnes
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, the Netherlands
| | - Stefanie Dimmeler
- Institute of Cardiovascular Regeneration, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Rhein-Main, Potsdamer Strasse 58, 10785, Berlin, Germany
| | - Reinier A Boon
- Department of Physiology, Amsterdam UMC, VU University, De Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands.
- Amsterdam Cardiovascular Sciences, Microcirculation, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
- Institute of Cardiovascular Regeneration, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site Rhein-Main, Potsdamer Strasse 58, 10785, Berlin, Germany.
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5
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Song S, Cho B, Weiner AT, Nissen SB, Ojeda Naharros I, Sanchez Bosch P, Suyama K, Hu Y, He L, Svinkina T, Udeshi ND, Carr SA, Perrimon N, Axelrod JD. Protein phosphatase 1 regulates core PCP signaling. EMBO Rep 2023; 24:e56997. [PMID: 37975164 PMCID: PMC10702827 DOI: 10.15252/embr.202356997] [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: 02/13/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/19/2023] Open
Abstract
Planar cell polarity (PCP) signaling polarizes epithelial cells within the plane of an epithelium. Core PCP signaling components adopt asymmetric subcellular localizations within cells to both polarize and coordinate polarity between cells. Achieving subcellular asymmetry requires additional effectors, including some mediating post-translational modifications of core components. Identification of such proteins is challenging due to pleiotropy. We used mass spectrometry-based proximity labeling proteomics to identify such regulators in the Drosophila wing. We identified the catalytic subunit of protein phosphatase1, Pp1-87B, and show that it regulates core protein polarization. Pp1-87B interacts with the core protein Van Gogh and at least one serine/threonine kinase, Dco/CKIε, that is known to regulate PCP. Pp1-87B modulates Van Gogh subcellular localization and directs its dephosphorylation in vivo. PNUTS, a Pp1 regulatory subunit, also modulates PCP. While the direct substrate(s) of Pp1-87B in control of PCP is not known, our data support the model that cycling between phosphorylated and unphosphorylated forms of one or more core PCP components may regulate acquisition of asymmetry. Finally, our screen serves as a resource for identifying additional regulators of PCP signaling.
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Affiliation(s)
- Song Song
- Department of PathologyStanford University School of MedicineStanfordCAUSA
- Present address:
GenScriptPiscatawayNJUSA
| | - Bomsoo Cho
- Department of PathologyStanford University School of MedicineStanfordCAUSA
| | - Alexis T Weiner
- Department of PathologyStanford University School of MedicineStanfordCAUSA
| | - Silas Boye Nissen
- Department of PathologyStanford University School of MedicineStanfordCAUSA
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW)University of CopenhagenCopenhagenDenmark
| | - Irene Ojeda Naharros
- Department of OphthalmologyUniversity of California, San FranciscoSan FranciscoCAUSA
| | | | - Kaye Suyama
- Department of PathologyStanford University School of MedicineStanfordCAUSA
| | - Yanhui Hu
- Department of Genetics, Blavatnik Institute, Harvard Medical SchoolHarvard UniversityBostonMAUSA
| | - Li He
- Department of Genetics, Blavatnik Institute, Harvard Medical SchoolHarvard UniversityBostonMAUSA
- Present address:
School of Life SciencesUniversity of Science and Technology of ChinaHefeiChina
| | | | | | | | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical SchoolHarvard UniversityBostonMAUSA
- Howard Hughes Medical InstituteBostonMAUSA
| | - Jeffrey D Axelrod
- Department of PathologyStanford University School of MedicineStanfordCAUSA
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6
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Kieft R, Zhang Y, Yan H, Schmitz RJ, Sabatini R. Protein Phosphatase PP1 Regulation of Pol II Phosphorylation is Linked to Transcription Termination and Allelic Exclusion of VSG Genes and TERRA in Trypanosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.21.563358. [PMID: 37905150 PMCID: PMC10614956 DOI: 10.1101/2023.10.21.563358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The genomes of Leishmania and trypanosomes are organized into polycistronic transcription units flanked by a modified DNA base J involved in promoting RNA polymerase II (Pol II) termination. We recently characterized a Leishmania complex containing a J-binding protein, PP1 protein phosphatase 1, and PP1 regulatory protein (PNUTS) that controls transcription termination potentially via dephosphorylation of Pol II by PP1. While T. brucei contains eight PP1 isoforms, none purified with the PNUTS complex, suggesting a unique PP1-independent mechanism of termination. We now demonstrate that the PP1-binding motif of TbPNUTS is required for function in termination in vivo and that TbPP1-1 modulates Pol II termination in T. brucei involving dephosphorylation of the C-terminal domain of the large subunit of Pol II. PP1-1 knock-down results in increased cellular levels of phosphorylated large subunit of Pol II accompanied by readthrough transcription and pervasive transcription of the entire genome by Pol II, including Pol I transcribed loci that are typically silent, such as telomeric VSG expression sites involved in antigenic variation and production of TERRA RNA. These results provide important insights into the mechanism underlying Pol II transcription termination in primitive eukaryotes that rely on polycistronic transcription and maintain allelic exclusion of VSG genes.
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7
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Song S, Cho B, Weiner AT, Nissen SB, Naharros IO, Bosch PS, Suyama K, Hu Y, He L, Svinkina T, Udeshi ND, Carr SA, Perrimon N, Axelrod JD. Protein phosphatase 1 regulates core PCP signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.556998. [PMID: 37745534 PMCID: PMC10515792 DOI: 10.1101/2023.09.12.556998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
PCP signaling polarizes epithelial cells within the plane of an epithelium. Core PCP signaling components adopt asymmetric subcellular localizations within cells to both polarize and coordinate polarity between cells. Achieving subcellular asymmetry requires additional effectors, including some mediating post-translational modifications of core components. Identification of such proteins is challenging due to pleiotropy. We used mass spectrometry-based proximity labeling proteomics to identify such regulators in the Drosophila wing. We identified the catalytic subunit of Protein Phosphatase1, Pp1-87B, and show that it regulates core protein polarization. Pp1-87B interacts with the core protein Van Gogh and at least one Serine/Threonine kinase, Dco/CKIε, that is known to regulate PCP. Pp1-87B modulates Van Gogh subcellular localization and directs its dephosphorylation in vivo. PNUTS, a Pp1 regulatory subunit, also modulates PCP. While the direct substrate(s) of Pp1-87B in control of PCP is not known, our data support the model that cycling between phosphorylated and unphosphorylated forms of one or more core PCP components may regulate acquisition of asymmetry. Finally, our screen serves as a resource for identifying additional regulators of PCP signaling.
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Affiliation(s)
- Song Song
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Present Address: GenScript, 860 Centennial Avenue, Piscataway, NJ, 08854, USA
| | - Bomsoo Cho
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alexis T. Weiner
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Silas Boye Nissen
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
| | - Irene Ojeda Naharros
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-3120, USA
| | - Pablo Sanchez Bosch
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kaye Suyama
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yanhui Hu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Li He
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Harvard University, Boston, MA 02115, USA
- Present Address: School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | | | | | | | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Harvard University, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Boston, MA 02138, USA
| | - Jeffrey D. Axelrod
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
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8
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Kieft R, Zhang Y, Yan H, Schmitz RJ, Sabatini R. Knockout of protein phosphatase 1 in Leishmania major reveals its role during RNA polymerase II transcription termination. Nucleic Acids Res 2023; 51:6208-6226. [PMID: 37194692 PMCID: PMC10325913 DOI: 10.1093/nar/gkad394] [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: 03/13/2023] [Revised: 04/26/2023] [Accepted: 05/04/2023] [Indexed: 05/18/2023] Open
Abstract
The genomes of kinetoplastids are organized into polycistronic transcription units that are flanked by a modified DNA base (base J, beta-D-glucosyl-hydroxymethyluracil). Previous work established a role of base J in promoting RNA polymerase II (Pol II) termination in Leishmania major and Trypanosoma brucei. We recently identified a PJW/PP1 complex in Leishmania containing a J-binding protein (JBP3), PP1 phosphatase 1, PP1 interactive-regulatory protein (PNUTS) and Wdr82. Analyses suggested the complex regulates transcription termination by recruitment to termination sites via JBP3-base J interactions and dephosphorylation of proteins, including Pol II, by PP1. However, we never addressed the role of PP1, the sole catalytic component, in Pol II transcription termination. We now demonstrate that deletion of the PP1 component of the PJW/PP1 complex in L. major, PP1-8e, leads to readthrough transcription at the 3'-end of polycistronic gene arrays. We show PP1-8e has in vitro phosphatase activity that is lost upon mutation of a key catalytic residue and associates with PNUTS via the conserved RVxF motif. Additionally, purified PJW complex with associated PP1-8e, but not complex lacking PP1-8e, led to dephosphorylation of Pol II, suggesting a direct role of PNUTS/PP1 holoenzymes in regulating transcription termination via dephosphorylating Pol II in the nucleus.
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Affiliation(s)
- Rudo Kieft
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA30602, USA
| | - Yang Zhang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA30602, USA
| | - Haidong Yan
- Department of Genetics, University of Georgia, Athens, GA30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA30602, USA
| | - Robert Sabatini
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA30602, USA
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9
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Rouvière JO, Salerno-Kochan A, Lykke-Andersen S, Garland W, Dou Y, Rathore O, Molska EŠ, Wu G, Schmid M, Bugai A, Jakobsen L, Žumer K, Cramer P, Andersen JS, Conti E, Jensen TH. ARS2 instructs early transcription termination-coupled RNA decay by recruiting ZC3H4 to nascent transcripts. Mol Cell 2023:S1097-2765(23)00384-2. [PMID: 37329882 DOI: 10.1016/j.molcel.2023.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/29/2023] [Accepted: 05/18/2023] [Indexed: 06/19/2023]
Abstract
The RNA-binding ARS2 protein is centrally involved in both early RNA polymerase II (RNAPII) transcription termination and transcript decay. Despite its essential nature, the mechanisms by which ARS2 enacts these functions have remained unclear. Here, we show that a conserved basic domain of ARS2 binds a corresponding acidic-rich, short linear motif (SLiM) in the transcription restriction factor ZC3H4. This interaction recruits ZC3H4 to chromatin to elicit RNAPII termination, independent of other early termination pathways defined by the cleavage and polyadenylation (CPA) and Integrator (INT) complexes. We find that ZC3H4, in turn, forms a direct connection to the nuclear exosome targeting (NEXT) complex, hereby facilitating rapid degradation of the nascent RNA. Hence, ARS2 instructs the coupled transcription termination and degradation of the transcript onto which it is bound. This contrasts with ARS2 function at CPA-instructed termination sites where the protein exclusively partakes in RNA suppression via post-transcriptional decay.
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Affiliation(s)
- Jérôme O Rouvière
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Anna Salerno-Kochan
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Munich, Germany
| | - Søren Lykke-Andersen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - William Garland
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Yuhui Dou
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Om Rathore
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Ewa Šmidová Molska
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Guifen Wu
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Andrii Bugai
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Lis Jakobsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Kristina Žumer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Munich, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark.
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10
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Riemondy K, Henriksen JC, Rissland OS. Intron dynamics reveal principles of gene regulation during the maternal-to-zygotic transition. RNA (NEW YORK, N.Y.) 2023; 29:596-608. [PMID: 36764816 PMCID: PMC10158999 DOI: 10.1261/rna.079168.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 01/29/2023] [Indexed: 05/06/2023]
Abstract
The maternal-to-zygotic transition (MZT) is a conserved embryonic process in animals where developmental control shifts from the maternal to zygotic genome. A key step in this transition is zygotic transcription, and deciphering the MZT requires classifying newly transcribed genes. However, due to current technological limitations, this starting point remains a challenge for studying many species. Here, we present an alternative approach that characterizes transcriptome changes based solely on RNA-seq data. By combining intron-mapping reads and transcript-level quantification, we characterized transcriptome dynamics during the Drosophila melanogaster MZT. Our approach provides an accessible platform to investigate transcriptome dynamics that can be applied to the MZT in nonmodel organisms. In addition to classifying zygotically transcribed genes, our analysis revealed that over 300 genes express different maternal and zygotic transcript isoforms due to alternative splicing, polyadenylation, and promoter usage. The vast majority of these zygotic isoforms have the potential to be subject to different regulatory control, and over two-thirds encode different proteins. Thus, our analysis reveals an additional layer of regulation during the MZT, where new zygotic transcripts can generate additional proteome diversity.
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Affiliation(s)
- Kent Riemondy
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Jesslyn C Henriksen
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Olivia S Rissland
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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11
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The PNUTS-PP1 complex acts as an intrinsic barrier to herpesvirus KSHV gene expression and replication. Nat Commun 2022; 13:7447. [PMID: 36460671 PMCID: PMC9718767 DOI: 10.1038/s41467-022-35268-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
Control of RNA Polymerase II (pol II) elongation is a critical component of gene expression in mammalian cells. The PNUTS-PP1 complex controls elongation rates, slowing pol II after polyadenylation sites to promote termination. The Kaposi's sarcoma-associated herpesvirus (KSHV) co-opts pol II to express its genes, but little is known about its regulation of pol II elongation. We identified PNUTS as a suppressor of a KSHV reporter gene in a genome-wide CRISPR screen. PNUTS depletion enhances global KSHV gene expression and overall viral replication. Mechanistically, PNUTS requires PP1 interaction, binds viral RNAs downstream of polyadenylation sites, and restricts transcription readthrough of viral genes. Surprisingly, PNUTS also represses productive elongation at the 5´ ends of the KSHV reporter and the KSHV T1.4 RNA. From these data, we conclude that PNUTS' activity constitutes an intrinsic barrier to KSHV replication likely by suppressing pol II elongation at promoter-proximal regions.
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12
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Liu Z, Wu A, Wu Z, Wang T, Pan Y, Li B, Zhang X, Yu M. TOX4 facilitates promoter-proximal pausing and C-terminal domain dephosphorylation of RNA polymerase II in human cells. Commun Biol 2022; 5:300. [PMID: 35365735 PMCID: PMC8975821 DOI: 10.1038/s42003-022-03214-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022] Open
Abstract
TOX4 is one of the regulatory factors of PP1 phosphatases with poorly understood functions. Here we show that chromatin occupancy pattern of TOX4 resembles that of RNA polymerase II (Pol II), and its loss increases cellular level of C-terminal domain (CTD) phosphorylated Pol II but mainly decreases Pol II occupancy on promoters. In addition, elongation rate analyses by 4sUDRB-seq suggest that TOX4 restricts pause release and early elongation but promotes late elongation. Moreover, TT-seq analyses indicate that TOX4 loss mainly decreases transcriptional output. Mechanistically, TOX4 may restrict pause release through facilitating CTD serine 2 and DSIF dephosphorylation, and promote Pol II recycling and reinitiation through facilitating CTD serines 2 and 5 dephosphorylation. Furthermore, among the PP1 phosphatases, TOX4 preferentially binds PP1α and is capable of facilitating Pol II CTD dephosphorylation in vitro. These results lay the foundation for a better understanding of the role of TOX4 in transcriptional regulation. As a role of TOX4, one of the regulatory proteins of PP1 phosphatases, in transcriptional regulation, authors here show that TOX4 restricts pause release and early productive elongation, and promotes Pol II recycling and transcriptional reinitiation.
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Affiliation(s)
- Ziling Liu
- Sheng Yushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Aiwei Wu
- Sheng Yushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Zhen Wu
- State key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 200438, Shanghai, China
| | - Talang Wang
- Sheng Yushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Yixuan Pan
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Bing Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Xumin Zhang
- State key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 200438, Shanghai, China
| | - Ming Yu
- Sheng Yushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China. .,Ministry of Education Key Laboratory of Systems Biomedicine, Shanghai Jiao Tong University, 200240, Shanghai, China.
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13
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Lalonde M, Trauner M, Werner M, Hamperl S. Consequences and Resolution of Transcription-Replication Conflicts. Life (Basel) 2021; 11:life11070637. [PMID: 34209204 PMCID: PMC8303131 DOI: 10.3390/life11070637] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/17/2022] Open
Abstract
Transcription–replication conflicts occur when the two critical cellular machineries responsible for gene expression and genome duplication collide with each other on the same genomic location. Although both prokaryotic and eukaryotic cells have evolved multiple mechanisms to coordinate these processes on individual chromosomes, it is now clear that conflicts can arise due to aberrant transcription regulation and premature proliferation, leading to DNA replication stress and genomic instability. As both are considered hallmarks of aging and human diseases such as cancer, understanding the cellular consequences of conflicts is of paramount importance. In this article, we summarize our current knowledge on where and when collisions occur and how these encounters affect the genome and chromatin landscape of cells. Finally, we conclude with the different cellular pathways and multiple mechanisms that cells have put in place at conflict sites to ensure the resolution of conflicts and accurate genome duplication.
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14
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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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15
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Landsverk HB, Sandquist LE, Bay LTE, Syljuåsen RG. New link between the RNA polymerase II-CTD and replication stress. Mol Cell Oncol 2021; 8:1910008. [PMID: 34027044 PMCID: PMC8128203 DOI: 10.1080/23723556.2021.1910008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Conflicts between transcription and replication are a major source of replication stress. Our recent findings show that proper dephosphorylation of Serine 5 in the carboxy-terminal domain (CTD) of DNA-directed RNA polymerase II subunit RPB1 is needed to prevent such conflicts in human cells.
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Affiliation(s)
- Helga B Landsverk
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Lise E Sandquist
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Lilli T E Bay
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Randi G Syljuåsen
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
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16
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Abstract
Unlike most other eukaryotes, Leishmania and other trypanosomatid protozoa have largely eschewed transcriptional control of gene expression, relying instead on posttranscriptional regulation of mRNAs derived from polycistronic transcription units (PTUs). In these parasites, a novel modified nucleotide base (β-d-glucopyranosyloxymethyluracil) known as J plays a critical role in ensuring that transcription termination occurs only at the end of each PTU, rather than at the polyadenylation sites of individual genes. To further understand the biology of J-associated processes, we used tandem affinity purification (TAP) tagging and mass spectrometry to reveal proteins that interact with the glucosyltransferase performing the final step in J synthesis. These studies identified four proteins reminiscent of subunits in the PTW/PP1 complex that controls transcription termination in higher eukaryotes. Moreover, bioinformatic analyses identified the DNA-binding subunit of Leishmania PTW/PP1 as a novel J-binding protein (JBP3), which is also part of another complex containing proteins with domains suggestive of a role in chromatin modification/remodeling. Additionally, JBP3 associates (albeit transiently and/or indirectly) with the trypanosomatid equivalent of the PAF1 complex involved in the regulation of transcription in other eukaryotes. The downregulation of JBP3 expression levels in Leishmania resulted in a substantial increase in transcriptional readthrough at the 3′ end of most PTUs. We propose that JBP3 recruits one or more of these complexes to the J-containing regions at the end of PTUs, where they halt the progression of the RNA polymerase. This decoupling of transcription termination from the splicing of individual genes enables the parasites’ unique reliance on polycistronic transcription and posttranscriptional regulation of gene expression. IMPORTANCELeishmania parasites cause a variety of serious human diseases, with no effective vaccine and emerging resistance to current drug therapy. We have previously shown that a novel DNA base called J is critical for transcription termination at the ends of the polycistronic gene clusters that are a hallmark of Leishmania and related trypanosomatids. Here, we describe a new J-binding protein (JBP3) associated with three different protein complexes that are reminiscent of those involved in the control of transcription in other eukaryotes. However, the parasite complexes have been reprogrammed to regulate transcription and gene expression in trypanosomatids differently than in the mammalian hosts, providing new opportunities to develop novel chemotherapeutic treatments against these important pathogens.
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17
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WDR82/PNUTS-PP1 Prevents Transcription-Replication Conflicts by Promoting RNA Polymerase II Degradation on Chromatin. Cell Rep 2020; 33:108469. [PMID: 33264625 DOI: 10.1016/j.celrep.2020.108469] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/05/2020] [Accepted: 11/10/2020] [Indexed: 02/08/2023] Open
Abstract
Transcription-replication (T-R) conflicts cause replication stress and loss of genome integrity. However, the transcription-related processes that restrain such conflicts are poorly understood. Here, we demonstrate that the RNA polymerase II (RNAPII) C-terminal domain (CTD) phosphatase protein phosphatase 1 (PP1) nuclear targeting subunit (PNUTS)-PP1 inhibits replication stress. Depletion of PNUTS causes lower EdU uptake, S phase accumulation, and slower replication fork rates. In addition, the PNUTS binding partner WDR82 also promotes RNAPII-CTD dephosphorylation and suppresses replication stress. RNAPII has a longer residence time on chromatin after depletion of PNUTS or WDR82. Furthermore, the RNAPII residence time is greatly enhanced by proteasome inhibition in control cells but less so in PNUTS- or WDR82-depleted cells, indicating that PNUTS and WDR82 promote degradation of RNAPII on chromatin. Notably, reduced replication is dependent on transcription and the phospho-CTD binding protein CDC73 after depletion of PNUTS/WDR82. Altogether, our results suggest that RNAPII-CTD dephosphorylation is required for the continuous turnover of RNAPII on chromatin, thereby preventing T-R conflicts.
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18
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Protein phosphatase 1 in tumorigenesis: is it worth a closer look? Biochim Biophys Acta Rev Cancer 2020; 1874:188433. [PMID: 32956763 DOI: 10.1016/j.bbcan.2020.188433] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/26/2020] [Accepted: 09/12/2020] [Indexed: 02/06/2023]
Abstract
Cancer cells take advantage of signaling cascades to meet their requirements for sustained growth and survival. Cell signaling is tightly controlled by reversible protein phosphorylation mechanisms, which require the counterbalanced action of protein kinases and protein phosphatases. Imbalances on this system are associated with cancer development and progression. Protein phosphatase 1 (PP1) is one of the most relevant protein phosphatases in eukaryotic cells. Despite the widely recognized involvement of PP1 in key biological processes, both in health and disease, its relevance in cancer has been largely neglected. Here, we provide compelling evidence that support major roles for PP1 in tumorigenesis.
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19
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Casamayor A, Ariño J. Controlling Ser/Thr protein phosphatase PP1 activity and function through interaction with regulatory subunits. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 122:231-288. [PMID: 32951813 DOI: 10.1016/bs.apcsb.2020.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein phosphatase 1 is a major Ser/Thr protein phosphatase activity in eukaryotic cells. It is composed of a catalytic polypeptide (PP1C), with little substrate specificity, that interacts with a large variety of proteins of diverse structure (regulatory subunits). The diversity of holoenzymes that can be formed explain the multiplicity of cellular functions under the control of this phosphatase. In quite a few cases, regulatory subunits have an inhibitory role, downregulating the activity of the phosphatase. In this chapter we shall introduce PP1C and review the most relevant families of PP1C regulatory subunits, with particular emphasis in describing the structural basis for their interaction.
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Affiliation(s)
- Antonio Casamayor
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
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20
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Kieft R, Zhang Y, Marand AP, Moran JD, Bridger R, Wells L, Schmitz RJ, Sabatini R. Identification of a novel base J binding protein complex involved in RNA polymerase II transcription termination in trypanosomes. PLoS Genet 2020; 16:e1008390. [PMID: 32084124 PMCID: PMC7055916 DOI: 10.1371/journal.pgen.1008390] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 03/04/2020] [Accepted: 01/08/2020] [Indexed: 11/18/2022] Open
Abstract
Base J, β-D-glucosyl-hydroxymethyluracil, is a modification of thymine DNA base involved in RNA Polymerase (Pol) II transcription termination in kinetoplastid protozoa. Little is understood regarding how specific thymine residues are targeted for J-modification or the mechanism of J regulated transcription termination. To identify proteins involved in J-synthesis, we expressed a tagged version of the J-glucosyltransferase (JGT) in Leishmania tarentolae, and identified four co-purified proteins by mass spectrometry: protein phosphatase (PP1), a homolog of Wdr82, a potential PP1 regulatory protein (PNUTS) and a protein containing a J-DNA binding domain (named JBP3). Gel shift studies indicate JBP3 is a J-DNA binding protein. Reciprocal tagging, co-IP and sucrose gradient analyses indicate PP1, JGT, JBP3, Wdr82 and PNUTS form a multimeric complex in kinetoplastids, similar to the mammalian PTW/PP1 complex involved in transcription termination via PP1 mediated dephosphorylation of Pol II. Using RNAi and analysis of Pol II termination by RNA-seq and RT-PCR, we demonstrate that ablation of PNUTS, JBP3 and Wdr82 lead to defects in Pol II termination at the 3'-end of polycistronic gene arrays in Trypanosoma brucei. Mutants also contain increased antisense RNA levels upstream of transcription start sites, suggesting an additional role of the complex in regulating termination of bi-directional transcription. In addition, PNUTS loss causes derepression of silent Variant Surface Glycoprotein genes involved in host immune evasion. Our results suggest a novel mechanistic link between base J and Pol II polycistronic transcription termination in kinetoplastids.
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Affiliation(s)
- Rudo Kieft
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Yang Zhang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Alexandre P. Marand
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Jose Dagoberto Moran
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Robert Bridger
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Robert J. Schmitz
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Robert Sabatini
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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21
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Localized Inhibition of Protein Phosphatase 1 by NUAK1 Promotes Spliceosome Activity and Reveals a MYC-Sensitive Feedback Control of Transcription. Mol Cell 2020; 77:1322-1339.e11. [PMID: 32006464 PMCID: PMC7086158 DOI: 10.1016/j.molcel.2020.01.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 12/09/2019] [Accepted: 01/07/2020] [Indexed: 01/19/2023]
Abstract
Deregulated expression of MYC induces a dependence on the NUAK1 kinase, but the molecular mechanisms underlying this dependence have not been fully clarified. Here, we show that NUAK1 is a predominantly nuclear protein that associates with a network of nuclear protein phosphatase 1 (PP1) interactors and that PNUTS, a nuclear regulatory subunit of PP1, is phosphorylated by NUAK1. Both NUAK1 and PNUTS associate with the splicing machinery. Inhibition of NUAK1 abolishes chromatin association of PNUTS, reduces spliceosome activity, and suppresses nascent RNA synthesis. Activation of MYC does not bypass the requirement for NUAK1 for spliceosome activity but significantly attenuates transcription inhibition. Consequently, NUAK1 inhibition in MYC-transformed cells induces global accumulation of RNAPII both at the pause site and at the first exon-intron boundary but does not increase mRNA synthesis. We suggest that NUAK1 inhibition in the presence of deregulated MYC traps non-productive RNAPII because of the absence of correctly assembled spliceosomes. Nuclear NUAK1 associates with PP1 and phosphorylates its targeting subunit PNUTS NUAK1, PP1, and PNUTS form a trimer that associates with the splicing machinery Inhibition of NUAK1 reduces spliceosome activity and nascent RNA synthesis When MYC is deregulated, NUAK1 inhibition traps RNAPII at the intron-exon boundary
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22
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Control of RNA Pol II Speed by PNUTS-PP1 and Spt5 Dephosphorylation Facilitates Termination by a "Sitting Duck Torpedo" Mechanism. Mol Cell 2019; 76:896-908.e4. [PMID: 31677974 DOI: 10.1016/j.molcel.2019.09.031] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/14/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
Control of transcription speed, which influences many co-transcriptional processes, is poorly understood. We report that PNUTS-PP1 phosphatase is a negative regulator of RNA polymerase II (Pol II) elongation rate. The PNUTS W401A mutation, which disrupts PP1 binding, causes genome-wide acceleration of transcription associated with hyper-phosphorylation of the Spt5 elongation factor. Immediately downstream of poly(A) sites, Pol II decelerates from >2 kb/min to <1 kb/min, which correlates with Spt5 dephosphorylation. Pol II deceleration and Spt5 dephosphorylation require poly(A) site recognition and the PNUTS-PP1 complex, which is in turn necessary for transcription termination. These results lead to a model for termination, the "sitting duck torpedo" mechanism, where poly(A) site-dependent deceleration caused by PNUTS-PP1 and Spt5 dephosphorylation is required to convert Pol II into a viable target for the Xrn2 terminator exonuclease. Spt5 and its bacterial homolog NusG therefore have related functions controlling kinetic competition between RNA polymerases and the termination factors that pursue them.
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23
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Landsverk HB, Sandquist LE, Sridhara SC, Rødland GE, Sabino JC, de Almeida SF, Grallert B, Trinkle-Mulcahy L, Syljuåsen RG. Regulation of ATR activity via the RNA polymerase II associated factors CDC73 and PNUTS-PP1. Nucleic Acids Res 2019; 47:1797-1813. [PMID: 30541148 PMCID: PMC6393312 DOI: 10.1093/nar/gky1233] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/23/2018] [Accepted: 11/30/2018] [Indexed: 12/22/2022] Open
Abstract
Ataxia telangiectasia mutated and Rad3-related (ATR) kinase is a key factor activated by DNA damage and replication stress. An alternative pathway for ATR activation has been proposed to occur via stalled RNA polymerase II (RNAPII). However, how RNAPII might signal to activate ATR remains unknown. Here, we show that ATR signaling is increased after depletion of the RNAPII phosphatase PNUTS-PP1, which dephosphorylates RNAPII in its carboxy-terminal domain (CTD). High ATR signaling was observed in the absence and presence of ionizing radiation, replication stress and even in G1, but did not correlate with DNA damage or RPA chromatin loading. R-loops were enhanced, but overexpression of EGFP-RNaseH1 only slightly reduced ATR signaling after PNUTS depletion. However, CDC73, which interacted with RNAPII in a phospho-CTD dependent manner, was required for the high ATR signaling, R-loop formation and for activation of the endogenous G2 checkpoint after depletion of PNUTS. In addition, ATR, RNAPII and CDC73 co-immunoprecipitated. Our results suggest a novel pathway involving RNAPII, CDC73 and PNUTS-PP1 in ATR signaling and give new insight into the diverse functions of ATR.
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Affiliation(s)
- Helga B Landsverk
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Lise E Sandquist
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Sreerama C Sridhara
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Gro Elise Rødland
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - João C Sabino
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Sérgio F de Almeida
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Beata Grallert
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Laura Trinkle-Mulcahy
- Department of Cellular and Molecular Medicine and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Randi G Syljuåsen
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
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24
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Dingar D, Tu WB, Resetca D, Lourenco C, Tamachi A, De Melo J, Houlahan KE, Kalkat M, Chan PK, Boutros PC, Raught B, Penn LZ. MYC dephosphorylation by the PP1/PNUTS phosphatase complex regulates chromatin binding and protein stability. Nat Commun 2018; 9:3502. [PMID: 30158517 PMCID: PMC6115416 DOI: 10.1038/s41467-018-05660-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 07/06/2018] [Indexed: 01/08/2023] Open
Abstract
The c-MYC (MYC) oncoprotein is deregulated in over 50% of cancers, yet regulatory mechanisms controlling MYC remain unclear. To this end, we interrogated the MYC interactome using BioID mass spectrometry (MS) and identified PP1 (protein phosphatase 1) and its regulatory subunit PNUTS (protein phosphatase-1 nuclear-targeting subunit) as MYC interactors. We demonstrate that endogenous MYC and PNUTS interact across multiple cell types and that they co-occupy MYC target gene promoters. Inhibiting PP1 by RNAi or pharmacological inhibition results in MYC hyperphosphorylation at multiple serine and threonine residues, leading to a decrease in MYC protein levels due to proteasomal degradation through the canonical SCFFBXW7 pathway. MYC hyperphosphorylation can be rescued specifically with exogenous PP1, but not other phosphatases. Hyperphosphorylated MYC retained interaction with its transcriptional partner MAX, but binding to chromatin is significantly compromised. Our work demonstrates that PP1/PNUTS stabilizes chromatin-bound MYC in proliferating cells. Deregulated MYC activity is oncogenic and is deregulated in a large fraction of human cancers. Here the authors find that protein phosphatase 1 and its regulatory subunit PNUTS controls MYC stability and its interaction with chromatin.
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Affiliation(s)
- Dharmendra Dingar
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada
| | - William B Tu
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada
| | - Diana Resetca
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada
| | - Corey Lourenco
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada
| | - Aaliya Tamachi
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada
| | - Jason De Melo
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada
| | - Kathleen E Houlahan
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada.,Ontario Institute for Cancer Research, Toronto, ON Canada M5G 0A3, Canada
| | - Manpreet Kalkat
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada
| | - Pak-Kei Chan
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada
| | - Paul C Boutros
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada.,Ontario Institute for Cancer Research, Toronto, ON Canada M5G 0A3, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada M5S 1A8, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada
| | - Linda Z Penn
- Princess Margaret Cancer Centre, University Health Network, Toronto, M5G 1L7, ON, Canada. .,Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, Canada.
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25
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Wu D, De Wever V, Derua R, Winkler C, Beullens M, Van Eynde A, Bollen M. A substrate-trapping strategy for protein phosphatase PP1 holoenzymes using hypoactive subunit fusions. J Biol Chem 2018; 293:15152-15162. [PMID: 30115685 DOI: 10.1074/jbc.ra118.004132] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/13/2018] [Indexed: 01/24/2023] Open
Abstract
The protein Ser/Thr phosphatase PP1 catalyzes an important fraction of protein dephosphorylation events and forms highly specific holoenzymes through an association with regulatory interactors of protein phosphatase one (RIPPOs). The functional characterization of individual PP1 holoenzymes is hampered by the lack of straightforward strategies for substrate mapping. Because efficient substrate recruitment often involves binding to both PP1 and its associated RIPPO, here we examined whether PP1-RIPPO fusions can be used to trap substrates for further analysis. Fusions of an hypoactive point mutant of PP1 and either of four tested RIPPOs accumulated in HEK293T cells with their associated substrates and were co-immunoprecipitated for subsequent identification of the substrates by immunoblotting or MS analysis. Hypoactive fusions were also used to study RIPPOs themselves as substrates for associated PP1. In contrast, substrate trapping was barely detected with active PP1-RIPPO fusions or with nonfused PP1 or RIPPO subunits. Our results suggest that hypoactive fusions of PP1 subunits represent an easy-to-use tool for substrate identification of individual holoenzymes.
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Affiliation(s)
- Dan Wu
- From the Laboratory of Biosignaling and Therapeutics
| | | | - Rita Derua
- the Protein Phosphorylation and Proteomics Lab, KU Leuven Department of Cellular and Molecular Medicine, and.,SyBioMa, University of Leuven, 3000 Leuven, Belgium
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26
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Gil RS, Vagnarelli P. Protein phosphatases in chromatin structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:90-101. [PMID: 30036566 PMCID: PMC6227384 DOI: 10.1016/j.bbamcr.2018.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/29/2018] [Accepted: 07/18/2018] [Indexed: 12/19/2022]
Abstract
Chromatin structure and dynamics are highly controlled and regulated processes that play an essential role in many aspects of cell biology. The chromatin transition stages and the factors that control this process are regulated by post-translation modifications, including phosphorylation. While the role of protein kinases in chromatin dynamics has been quite well studied, the nature and regulation of the counteracting phosphatases represent an emerging field but are still at their infancy. In this review we summarize the current literature on phosphatases involved in the regulation of chromatin structure and dynamics, with emphases on the major knowledge gaps that should require attention and more investigation.
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Affiliation(s)
- Raquel Sales Gil
- Colleges of Health and Life Science, Research Institute for Environment Health and Society, Brunel University London, London UB8 3PH, UK
| | - Paola Vagnarelli
- Colleges of Health and Life Science, Research Institute for Environment Health and Society, Brunel University London, London UB8 3PH, UK.
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27
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Richard JLC, Eichhorn PJA. Deciphering the roles of lncRNAs in breast development and disease. Oncotarget 2018; 9:20179-20212. [PMID: 29732012 PMCID: PMC5929455 DOI: 10.18632/oncotarget.24591] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 02/21/2018] [Indexed: 02/06/2023] Open
Abstract
Breast cancer is the second leading cause of cancer related deaths in women. It is therefore important to understand the mechanisms underlying breast cancer development as well as raises the need for enhanced, non-invasive strategies for novel prognostic and diagnostic methods. The emergence of long non-coding RNAs (lncRNAs) as potential key players in neoplastic disease has received considerable attention over the past few years. This relatively new class of molecular regulators has been shown from ongoing research to act as critical players for key biological processes. Deregulated expression levels of lncRNAs have been observed in a number of cancers including breast cancer. Furthermore, lncRNAs have been linked to breast cancer initiation, progression, metastases and to limit sensitivity to certain targeted therapeutics. In this review we provide an update on the lncRNAs associated with breast cancer and mammary gland development and illustrate the versatility of such lncRNAs in gene control, differentiation and development both in normal physiological conditions and in diseased states. We also highlight the therapeutic and diagnostic potential of lncRNAs in cancer.
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Affiliation(s)
- John Lalith Charles Richard
- Cancer Science Institute of Singapore, National University of Singapore, 117599, Singapore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
- Current Address: Genome Institute of Singapore, Agency for Science Technology and Research, 138672, Singapore
| | - Pieter Johan Adam Eichhorn
- Cancer Science Institute of Singapore, National University of Singapore, 117599, Singapore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
- School of Pharmacy, Curtin University, Perth, 6845, Australia
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28
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Jonchère V, Alqadri N, Herbert J, Dodgson L, Mason D, Messina G, Falciani F, Bennett D. Transcriptional responses to hyperplastic MRL signalling in Drosophila. Open Biol 2017; 7:rsob.160306. [PMID: 28148822 PMCID: PMC5356444 DOI: 10.1098/rsob.160306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/04/2017] [Indexed: 12/19/2022] Open
Abstract
Recent work has implicated the actin cytoskeleton in tissue size control and tumourigenesis, but how changes in actin dynamics contribute to hyperplastic growth is still unclear. Overexpression of Pico, the only Drosophila Mig-10/RIAM/Lamellipodin adapter protein family member, has been linked to tissue overgrowth via its effect on the myocardin-related transcription factor (Mrtf), an F-actin sensor capable of activating serum response factor (SRF). Transcriptional changes induced by acute Mrtf/SRF signalling have been largely linked to actin biosynthesis and cytoskeletal regulation. However, by RNA profiling, we find that the common response to chronic mrtf and pico overexpression in wing discs was upregulation of ribosome protein and mitochondrial genes, which are conserved targets for Mrtf/SRF and are known growth drivers. Consistent with their ability to induce a common transcriptional response and activate SRF signalling in vitro, we found that both pico and mrtf stimulate expression of an SRF-responsive reporter gene in wing discs. In a functional genetic screen, we also identified deterin, which encodes Drosophila Survivin, as a putative Mrtf/SRF target that is necessary for pico-mediated tissue overgrowth by suppressing proliferation-associated cell death. Taken together, our findings raise the possibility that distinct targets of Mrtf/SRF may be transcriptionally induced depending on the duration of upstream signalling.
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Affiliation(s)
- Vincent Jonchère
- Department of Biochemistry, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Nada Alqadri
- Department of Biochemistry, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - John Herbert
- Centre for Computational Biology and Modelling (CCBM), Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Lauren Dodgson
- Department of Biochemistry, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - David Mason
- Centre for Cell Imaging, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Giovanni Messina
- Department of Biochemistry, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Francesco Falciani
- Centre for Computational Biology and Modelling (CCBM), Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Daimark Bennett
- Department of Biochemistry, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK .,Centre for Cell Imaging, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
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29
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Liu X, Gao Y, Ye H, Gerrin S, Ma F, Wu Y, Zhang T, Russo J, Cai C, Yuan X, Liu J, Chen S, Balk SP. Positive feedback loop mediated by protein phosphatase 1α mobilization of P-TEFb and basal CDK1 drives androgen receptor in prostate cancer. Nucleic Acids Res 2017; 45:3738-3751. [PMID: 28062857 PMCID: PMC5397168 DOI: 10.1093/nar/gkw1291] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/25/2016] [Indexed: 01/05/2023] Open
Abstract
P-TEFb (CDK9/cyclin T) plays a central role in androgen receptor (AR)-mediated transactivation by phosphorylating both RNA polymerase 2 complex proteins and AR at S81. CDK9 dephosphorylation mobilizes P-TEFb from an inhibitory 7SK ribonucleoprotein complex, but mechanisms targeting phosphatases to P-TEFb are unclear. We show that AR recruits protein phosphatase 1α (PP1α), resulting in P-TEFb mobilization and CDK9-mediated AR S81 phosphorylation. This increased pS81 enhances p300 recruitment, histone acetylation, BRD4 binding and subsequent further recruitment of P-TEFb, generating a positive feedback loop that sustains transcription. AR S81 is also phosphorylated by CDK1, and blocking basal CDK1-mediated S81 phosphorylation markedly suppresses AR activity and initiation of this positive feedback loop. Finally, androgen-independent AR activity in castration-resistant prostate cancer (CRPC) cells is driven by increased CDK1-mediated S81 phosphorylation. Collectively these findings reveal a mechanism involving PP1α, CDK9 and CDK1 that is used by AR to initiate and sustain P-TEFb activity, which may be exploited to drive AR in CRPC.
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Affiliation(s)
- Xiaming Liu
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Yanfei Gao
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - HuiHui Ye
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Sean Gerrin
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Fen Ma
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Yiming Wu
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Tengfei Zhang
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Joshua Russo
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Changmeng Cai
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Xin Yuan
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Jihong Liu
- Department of Urology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shaoyong Chen
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Steven P Balk
- Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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30
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Liu S, Xu T, Wu X, Lin Y, Bao D, Di Y, Ma T, Dang Y, Jia P, Xian J, Wang A, Liu Y. Pomegranate peel extract attenuates D-galactose-induced oxidative stress and hearing loss by regulating PNUTS/PP1 activity in the mouse cochlea. Neurobiol Aging 2017; 59:30-40. [PMID: 28837860 DOI: 10.1016/j.neurobiolaging.2017.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 07/11/2017] [Accepted: 07/15/2017] [Indexed: 01/20/2023]
Abstract
Oxidative stress is considered to be a major contributor to age-related hearing loss (ARHL). Here, we investigated whether pomegranate peel extract (PPE) protected against hearing loss by decreased oxidative stress in the cochlea of D-galactose-induced accelerated aging mice. The aging mice exhibited an increase in hearing threshold shifts and hair cells loss, which were improved in the PPE-treated aging mice. The aging mice also exhibited an increase in 4-hydroxynonenal, the expression of protein phosphatase 1 nuclear targeting subunit (PNUTS), p53 and caspase-3, and a decrease in protein phosphatase 1 (PP1) and MDM2 in the cochlea. PPE treatment reversed the changes in aforementioned molecules. Our results suggested that PPE can protect against ARHL, the underlying mechanisms may involve in the inhibition of oxidative damage of cochlea, possibly by regulating PNUTS/PP1 pathway. The results from the present study provide a new therapeutic strategy to use PPE for prevention of ARHL.
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Affiliation(s)
- Shuangyue Liu
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Tao Xu
- Life Science Institute, Jinzhou Medical University, Jinzhou, P.R. China
| | - Xidi Wu
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Yuhan Lin
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Dongyan Bao
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Yang Di
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Tingting Ma
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Yan Dang
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Peili Jia
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Jianqiao Xian
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China
| | - Aimei Wang
- Department of Physiology, Jinzhou Medical University, Jinzhou, P.R. China.
| | - Yongxin Liu
- Department of Otorhinolaryngology-Head and Neck Surgery, the First Hospital of Jinzhou Medical University, Jinzhou, P.R. China.
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31
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Weidle UH, Birzele F, Kollmorgen G, Rüger R. Long Non-coding RNAs and their Role in Metastasis. Cancer Genomics Proteomics 2017; 14:143-160. [PMID: 28446530 PMCID: PMC5420816 DOI: 10.21873/cgp.20027] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/13/2017] [Accepted: 03/15/2017] [Indexed: 02/08/2023] Open
Abstract
The perception of long non-coding RNAs as chunk RNA and transcriptional noise has been steadily replaced by their role as validated targets for a diverse set of physiological processes in the past few years. However, for the vast majority of lncRNAs their precise mode of action and physiological function remain to be uncovered. A large body of evidence has revealed their essential role in all stages of cancirogenesis and metastasis. In this review we focus on the role of lncRNAs in metastasis. We grouped selected lncRNAs into three categories based on in vitro and in vivo mode of action-related studies and clinical relevance for metastasis. Grouped according to their mode of action, in category I we discuss lncRNAs such as CCAT2, DREH, LET, NKILA, treRNA, HOTAIR, H19, FENDRR, lincROR, MALAT, GClnc1, BCAR4, SCHLAP1 and lncRNA ATP, all lncRNAs with in vitro and in vivo metastasis-related data and clinical significance. In category II we discuss lncRNAs CCAT1, PCAT1, PTENgp1, GPLINC, MEG3, ZEB2-AS, LCT13, ANRIL, NBAT1 and lncTCF7 all characterized by their mode of action in vitro and clinical significance, but pending or preliminary in vivo data. Finally, under category III, we discuss lncRNAs BANCR, FRLnc1, SPRY4-IT1 and LIMT with partially or poorly-resolved mode of action and varying degree of validation in clinical metastasis. Finally we discuss metastasis-related translational aspects of lncRNAs.
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Affiliation(s)
- Ulrich H Weidle
- Roche Innovation Center Munich, Roche Diagnostics GmbH, Penzberg, Germany
| | - Fabian Birzele
- Roche Innovation Center Basel, F. Hofman La Roche, Basel, Switzerland
| | - Gwen Kollmorgen
- Roche Innovation Center Munich, Roche Diagnostics GmbH, Penzberg, Germany
| | - Rüdiger Rüger
- Roche Innovation Center Munich, Roche Diagnostics GmbH, Penzberg, Germany
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32
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MRL proteins cooperate with activated Ras in glia to drive distinct oncogenic outcomes. Oncogene 2017; 36:4311-4322. [PMID: 28346426 PMCID: PMC5537612 DOI: 10.1038/onc.2017.68] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 01/16/2017] [Accepted: 02/10/2017] [Indexed: 12/13/2022]
Abstract
The Mig10/RIAM/Lpd (MRL) adapter protein Lpd regulates actin dynamics through interactions with Scar/WAVE and Ena/VASP proteins to promote the formation of cellular protrusions and to stimulate invasive migration. However, the ability of MRL proteins to interact with multiple actin regulators and to promote serum response factor (SRF) signalling has raised the question of whether MRL proteins employ alternative downstream mechanisms to drive oncogenic processes in a context-dependent manner. Here, using a Drosophila model, we show that overexpression of either human Lpd or its Drosophila orthologue Pico can promote growth and invasion of RasV12-induced cell tumours in the brain. Notably, effects were restricted to two populations of Repo-positive glial cells: an invasive population, characterized by JNK-dependent elevation of Mmp1 expression, and a hyperproliferative population lacking elevated JNK signalling. JNK activation was not triggered by reactive immune cell signalling, implicating the involvement of an intrinsic stress response. The ability to promote dissemination of RasV12-induced tumours was shared by a subset of actin regulators, including, most prominently, Chicadee/Profilin, which directly interacts with Pico, and, Mal, a cofactor for serum response factor that responds to changes in G:F actin dynamics. Suppression of Mal activity partially abrogated the ability of pico to promote invasion of RasV12 tumours. Furthermore, we found that larval glia are enriched for serum response factor expression, explaining the apparent sensitivity of glial cells to Pico/RasV12 overexpression. Taken together, our findings indicate that MRL proteins cooperate with oncogenic Ras to promote formation of glial tumours, and that, in this context, Mal/serum response factor activation is rate-limiting for tumour dissemination.
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33
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Ismail TM, Bennett D, Platt-Higgins AM, Al-Medhity M, Barraclough R, Rudland PS. S100A4 Elevation Empowers Expression of Metastasis Effector Molecules in Human Breast Cancer. Cancer Res 2017; 77:780-789. [PMID: 27927689 PMCID: PMC5321524 DOI: 10.1158/0008-5472.can-16-1802] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/19/2016] [Accepted: 10/27/2016] [Indexed: 12/23/2022]
Abstract
Many human glandular cancers metastasize along nerve tracts, but the mechanisms involved are generally poorly understood. The calcium-binding protein S100A4 is expressed at elevated levels in human cancers, where it has been linked to increased invasion and metastasis. Here we report genetic studies in a Drosophila model to define S100A4 effector functions that mediate metastatic dissemination of mutant Ras-induced tumors in the developing nervous system. In flies overexpressing mutant RasVal12 and S100A4, there was a significant increase in activation of the stress kinase JNK and production of the matrix metalloproteinase MMP1. Genetic or chemical blockades of JNK and MMP1 suppressed metastatic dissemination associated with S100A4 elevation, defining required signaling pathway(s) for S100A4 in this setting. In clinical specimens of human breast cancer, elevated levels of the mammalian paralogs MMP2, MMP9, and MMP13 are associated with a 4- to 9-fold relative decrease in patient survival. In individual tumors, levels of MMP2 and MMP13 correlated more closely with levels of S100A4, whereas MMP9 levels correlated more closely with the S100 family member S100P. Overall, our results suggest the existence of evolutionarily conserved pathways used by S100A4 to promote metastatic dissemination, with potential prognostic and therapeutic implications for metastasis by cancers that preferentially exploit nerve tract migration routes. Cancer Res; 77(3); 780-9. ©2016 AACR.
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Affiliation(s)
- Thamir M Ismail
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Daimark Bennett
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Angela M Platt-Higgins
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Morteta Al-Medhity
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Roger Barraclough
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Philip S Rudland
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
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34
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Biophysical Analysis of the N-Terminal Domain from the Human Protein Phosphatase 1 Nuclear Targeting Subunit PNUTS Suggests an Extended Transcription Factor TFIIS-Like Fold. Protein J 2016; 35:340-345. [DOI: 10.1007/s10930-016-9677-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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35
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Interconnections Between RNA-Processing Pathways Revealed by a Sequencing-Based Genetic Screen for Pre-mRNA Splicing Mutants in Fission Yeast. G3-GENES GENOMES GENETICS 2016; 6:1513-23. [PMID: 27172183 PMCID: PMC4889648 DOI: 10.1534/g3.116.027508] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Pre-mRNA splicing is an essential component of eukaryotic gene expression and is highly conserved from unicellular yeasts to humans. Here, we present the development and implementation of a sequencing-based reverse genetic screen designed to identify nonessential genes that impact pre-mRNA splicing in the fission yeast Schizosaccharomyces pombe, an organism that shares many of the complex features of splicing in higher eukaryotes. Using a custom-designed barcoding scheme, we simultaneously queried ∼3000 mutant strains for their impact on the splicing efficiency of two endogenous pre-mRNAs. A total of 61 nonessential genes were identified whose deletions resulted in defects in pre-mRNA splicing; enriched among these were factors encoding known or predicted components of the spliceosome. Included among the candidates identified here are genes with well-characterized roles in other RNA-processing pathways, including heterochromatic silencing and 3ʹ end processing. Splicing-sensitive microarrays confirm broad splicing defects for many of these factors, revealing novel functional connections between these pathways.
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36
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Rebelo S, Santos M, Martins F, da Cruz e Silva EF, da Cruz e Silva OA. Protein phosphatase 1 is a key player in nuclear events. Cell Signal 2015; 27:2589-98. [DOI: 10.1016/j.cellsig.2015.08.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/31/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022]
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37
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Austenaa L, Barozzi I, Simonatto M, Masella S, Della Chiara G, Ghisletti S, Curina A, de Wit E, Bouwman B, de Pretis S, Piccolo V, Termanini A, Prosperini E, Pelizzola M, de Laat W, Natoli G. Transcription of Mammalian cis-Regulatory Elements Is Restrained by Actively Enforced Early Termination. Mol Cell 2015; 60:460-74. [DOI: 10.1016/j.molcel.2015.09.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 08/13/2015] [Accepted: 09/17/2015] [Indexed: 12/12/2022]
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38
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Verheyen T, Görnemann J, Verbinnen I, Boens S, Beullens M, Van Eynde A, Bollen M. Genome-wide promoter binding profiling of protein phosphatase-1 and its major nuclear targeting subunits. Nucleic Acids Res 2015; 43:5771-84. [PMID: 25990731 PMCID: PMC4499128 DOI: 10.1093/nar/gkv500] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 05/05/2015] [Indexed: 12/11/2022] Open
Abstract
Protein phosphatase-1 (PP1) is a key regulator of transcription and is targeted to promoter regions via associated proteins. However, the chromatin binding sites of PP1 have never been studied in a systematic and genome-wide manner. Methylation-based DamID profiling in HeLa cells has enabled us to map hundreds of promoter binding sites of PP1 and three of its major nuclear interactors, i.e. RepoMan, NIPP1 and PNUTS. Our data reveal that the α, β and γ isoforms of PP1 largely bind to distinct subsets of promoters and can also be differentiated by their promoter binding pattern. PP1β emerged as the major promoter-associated isoform and shows an overlapping binding profile with PNUTS at dozens of active promoters. Surprisingly, most promoter binding sites of PP1 are not shared with RepoMan, NIPP1 or PNUTS, hinting at the existence of additional, largely unidentified chromatin-targeting subunits. We also found that PP1 is not required for the global chromatin targeting of RepoMan, NIPP1 and PNUTS, but alters the promoter binding specificity of NIPP1. Our data disclose an unexpected specificity and complexity in the promoter binding of PP1 isoforms and their chromatin-targeting subunits.
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Affiliation(s)
- Toon Verheyen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Janina Görnemann
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Iris Verbinnen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Shannah Boens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
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Xing Z, Lin A, Li C, Liang K, Wang S, Liu Y, Park PK, Qin L, Wei Y, Hawke DH, Hung MC, Lin C, Yang L. lncRNA directs cooperative epigenetic regulation downstream of chemokine signals. Cell 2014; 159:1110-1125. [PMID: 25416949 DOI: 10.1016/j.cell.2014.10.013] [Citation(s) in RCA: 357] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 07/07/2014] [Accepted: 09/24/2014] [Indexed: 11/17/2022]
Abstract
lncRNAs are known to regulate a number of different developmental and tumorigenic processes. Here, we report a role for lncRNA BCAR4 in breast cancer metastasis that is mediated by chemokine-induced binding of BCAR4 to two transcription factors with extended regulatory consequences. BCAR4 binding of SNIP1 and PNUTS in response to CCL21 releases the SNIP1's inhibition of p300-dependent histone acetylation, which in turn enables the BCAR4-recruited PNUTS to bind H3K18ac and relieve inhibition of RNA Pol II via activation of the PP1 phosphatase. This mechanism activates a noncanonical Hedgehog/GLI2 transcriptional program that promotes cell migration. BCAR4 expression correlates with advanced breast cancers, and therapeutic delivery of locked nucleic acids (LNAs) targeting BCAR4 strongly suppresses breast cancer metastasis in mouse models. The findings reveal a disease-relevant lncRNA mechanism consisting of both direct coordinated protein recruitment and indirect regulation of transcription factors.
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Affiliation(s)
- Zhen Xing
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Aifu Lin
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chunlai Li
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ke Liang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Shouyu Wang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yang Liu
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Peter K Park
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Li Qin
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yongkun Wei
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - David H Hawke
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Cancer Biology Program, The University of Texas Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Graduate Institute of Cancer Biology and Center for Molecular Medicine, China Medical University, Taichung 404, Taiwan
| | - Chunru Lin
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Cancer Biology Program, The University of Texas Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Liuqing Yang
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Cancer Biology Program, The University of Texas Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Center for RNA Interference and Non-Coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Vanoosthuyse V, Legros P, van der Sar SJA, Yvert G, Toda K, Le Bihan T, Watanabe Y, Hardwick K, Bernard P. CPF-associated phosphatase activity opposes condensin-mediated chromosome condensation. PLoS Genet 2014; 10:e1004415. [PMID: 24945319 PMCID: PMC4063703 DOI: 10.1371/journal.pgen.1004415] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/16/2014] [Indexed: 12/03/2022] Open
Abstract
Functional links connecting gene transcription and condensin-mediated chromosome condensation have been established in species ranging from prokaryotes to vertebrates. However, the exact nature of these links remains misunderstood. Here we show in fission yeast that the 3′ end RNA processing factor Swd2.2, a component of the Cleavage and Polyadenylation Factor (CPF), is a negative regulator of condensin-mediated chromosome condensation. Lack of Swd2.2 does not affect the assembly of the CPF but reduces its association with chromatin. This causes only limited, context-dependent effects on gene expression and transcription termination. However, CPF-associated Swd2.2 is required for the association of Protein Phosphatase 1 PP1Dis2 with chromatin, through an interaction with Ppn1, a protein that we identify as the fission yeast homologue of vertebrate PNUTS. We demonstrate that Swd2.2, Ppn1 and PP1Dis2 form an independent module within the CPF, which provides an essential function in the absence of the CPF-associated Ssu72 phosphatase. We show that Ppn1 and Ssu72, like Swd2.2, are also negative regulators of condensin-mediated chromosome condensation. We conclude that Swd2.2 opposes condensin-mediated chromosome condensation by facilitating the function of the two CPF-associated phosphatases PP1 and Ssu72. Failure to properly condense chromosomes prior to their segregation in mitosis can lead to genome instability. The evolutionary-conserved condensin complex is key to the condensation process but the molecular mechanisms underlying its localization pattern on chromosomes remain unclear. Previous observations showed that the localization of condensin is intimately linked to regions of high transcription, although, somewhat paradoxically, its association with chromatin is disrupted by a processive polymerase activity. Here we identify several RNA processing factors as negative regulators of condensin in fission yeast. Two of these factors associate with PP1 phosphatase as an independent entity within the Cleavage and Polyadenylation Factor (CPF), a complex key for 3′ end RNA processing. Lack of this module induces only minor and context-dependent effects on gene expression. Our data suggest that this module helps maintaining the proper level of phosphatase activity within the CPF and thereby opposes the function of condensin in mitotic chromosome condensation.
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Affiliation(s)
- Vincent Vanoosthuyse
- CNRS, UMR5239, LBMC; Ecole Normale Supérieure de Lyon; Université Lyon 01, Lyon, France
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Pénélope Legros
- CNRS, UMR5239, LBMC; Ecole Normale Supérieure de Lyon; Université Lyon 01, Lyon, France
| | | | - Gaël Yvert
- CNRS, UMR5239, LBMC; Ecole Normale Supérieure de Lyon; Université Lyon 01, Lyon, France
| | - Kenji Toda
- Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Thierry Le Bihan
- SynthSys Edinburgh, The University of Edinburgh, Edinburgh, United Kingdom
| | - Yoshinori Watanabe
- Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Kevin Hardwick
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Pascal Bernard
- CNRS, UMR5239, LBMC; Ecole Normale Supérieure de Lyon; Université Lyon 01, Lyon, France
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Understanding the antagonism of retinoblastoma protein dephosphorylation by PNUTS provides insights into the PP1 regulatory code. Proc Natl Acad Sci U S A 2014; 111:4097-102. [PMID: 24591642 DOI: 10.1073/pnas.1317395111] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The serine/threonine protein phosphatase 1 (PP1) dephosphorylates hundreds of key biological targets by associating with nearly 200 regulatory proteins to form highly specific holoenzymes. However, how these proteins direct PP1 specificity and the ability to predict how these PP1 interacting proteins bind PP1 from sequence alone is still missing. PP1 nuclear targeting subunit (PNUTS) is a PP1 targeting protein that, with PP1, plays a central role in the nucleus, where it regulates chromatin decondensation, RNA processing, and the phosphorylation state of fundamental cell cycle proteins, including the retinoblastoma protein (Rb), p53, and MDM2. The molecular function of PNUTS in these processes is completely unknown. Here, we show that PNUTS, which is intrinsically disordered in its free form, interacts strongly with PP1 in a highly extended manner. Unexpectedly, PNUTS blocks one of PP1's substrate binding grooves while leaving the active site accessible. This interaction site, which we have named the arginine site, allowed us to define unique PP1 binding motifs, which advances our ability to predict how more than a quarter of the known PP1 regulators bind PP1. Additionally, the structure shows how PNUTS inhibits the PP1-mediated dephosphorylation of critical substrates, especially Rb, by blocking their binding sites on PP1, insights that are providing strategies for selectively enhancing Rb activity.
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