1
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van Breugel ME, Gerber A, van Leeuwen F. The choreography of chromatin in RNA polymerase III regulation. Biochem Soc Trans 2024; 52:1173-1189. [PMID: 38666598 DOI: 10.1042/bst20230770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 06/27/2024]
Abstract
Regulation of eukaryotic gene expression involves a dynamic interplay between the core transcriptional machinery, transcription factors, and chromatin organization and modification. While this applies to transcription by all RNA polymerase complexes, RNA polymerase III (RNAPIII) seems to be atypical with respect to its mechanisms of regulation. One distinctive feature of most RNAPIII transcribed genes is that they are devoid of nucleosomes, which relates to the high levels of transcription. Moreover, most of the regulatory sequences are not outside but within the transcribed open chromatin regions. Yet, several lines of evidence suggest that chromatin factors affect RNAPIII dynamics and activity and that gene sequence alone does not explain the observed regulation of RNAPIII. Here we discuss the role of chromatin modification and organization of RNAPIII transcribed genes and how they interact with the core transcriptional RNAPIII machinery and regulatory DNA elements in and around the transcribed genes.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
| | - Alan Gerber
- Department of Neurosurgery, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam 1081HV, The Netherlands
- Cancer Center Amsterdam, Cancer Biology, Amsterdam 1081HV, The Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
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2
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Chatterjee S, Ganguly A, Bhattacharyya D. Reprogramming nucleolar size by genetic perturbation of the extranuclear Rab GTPases Ypt6 and Ypt32. FEBS Lett 2024; 598:283-301. [PMID: 37994551 DOI: 10.1002/1873-3468.14776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 11/24/2023]
Abstract
Reprogramming organelle size has been proposed as a potential therapeutic approach. However, there have been few reports of nucleolar size reprogramming. We addressed this question in Saccharomyces cerevisiae by studying mutants having opposite effects on the nucleolar size. Mutations in genes involved in nuclear functions (KAR3, CIN8, and PRP45) led to enlarged nuclei/nucleoli, whereas mutations in secretory pathway family genes, namely the Rab-GTPases YPT6 and YPT32, reduced nucleolar size. When combined with mutations leading to enlarged nuclei/nucleoli, the YPT6 or YPT32 mutants can effectively reprogram the nuclear/nucleolar size almost back to normal. Our results further indicate that null mutation of YPT6 causes secretory stress that indirectly influences nuclear localization of Maf1, the negative regulator of RNA Polymerase III, which might reduce the nucleolar size by inhibiting nucleolar transcript enrichment.
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Affiliation(s)
- Shreosi Chatterjee
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
| | - Abira Ganguly
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
| | - Dibyendu Bhattacharyya
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
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3
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van Breugel ME, van Kruijsbergen I, Mittal C, Lieftink C, Brouwer I, van den Brand T, Kluin RJC, Hoekman L, Menezes RX, van Welsem T, Del Cortona A, Malik M, Beijersbergen RL, Lenstra TL, Verstrepen KJ, Pugh BF, van Leeuwen F. Locus-specific proteome decoding reveals Fpt1 as a chromatin-associated negative regulator of RNA polymerase III assembly. Mol Cell 2023; 83:4205-4221.e9. [PMID: 37995691 DOI: 10.1016/j.molcel.2023.10.037] [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: 04/18/2023] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023]
Abstract
Transcription of tRNA genes by RNA polymerase III (RNAPIII) is tuned by signaling cascades. The emerging notion of differential tRNA gene regulation implies the existence of additional regulatory mechanisms. However, tRNA gene-specific regulators have not been described. Decoding the local chromatin proteome of a native tRNA gene in yeast revealed reprogramming of the RNAPIII transcription machinery upon nutrient perturbation. Among the dynamic proteins, we identified Fpt1, a protein of unknown function that uniquely occupied RNAPIII-regulated genes. Fpt1 binding at tRNA genes correlated with the efficiency of RNAPIII eviction upon nutrient perturbation and required the transcription factors TFIIIB and TFIIIC but not RNAPIII. In the absence of Fpt1, eviction of RNAPIII was reduced, and the shutdown of ribosome biogenesis genes was impaired upon nutrient perturbation. Our findings provide support for a chromatin-associated mechanism required for RNAPIII eviction from tRNA genes and tuning the physiological response to changing metabolic demands.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Ila van Kruijsbergen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Chitvan Mittal
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
| | - Cor Lieftink
- Division of Molecular Carcinogenesis and Robotics and Screening Center, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Ineke Brouwer
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066 CX, the Netherlands
| | - Teun van den Brand
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Roelof J C Kluin
- Genomics Core Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Liesbeth Hoekman
- Proteomics Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Renée X Menezes
- Biostatistics Centre and Division of Psychosocial Research and Epidemiology, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Tibor van Welsem
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Andrea Del Cortona
- VIB-KU Leuven Center for Microbiology, KU Leuven, 3001 Heverlee-Leuven, Belgium
| | - Muddassir Malik
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis and Robotics and Screening Center, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Genomics Core Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066 CX, the Netherlands
| | - Kevin J Verstrepen
- VIB-KU Leuven Center for Microbiology, KU Leuven, 3001 Heverlee-Leuven, Belgium
| | - B Franklin Pugh
- Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands.
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4
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Willemin G, Mange F, Praz V, Lorrain S, Cousin P, Roger C, Willis IM, Hernandez N. Contrasting effects of whole-body and hepatocyte-specific deletion of the RNA polymerase III repressor Maf1 in the mouse. Front Mol Biosci 2023; 10:1297800. [PMID: 38143800 PMCID: PMC10746880 DOI: 10.3389/fmolb.2023.1297800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/15/2023] [Indexed: 12/26/2023] Open
Abstract
MAF1 is a nutrient-sensitive, TORC1-regulated repressor of RNA polymerase III (Pol III). MAF1 downregulation leads to increased lipogenesis in Drosophila melanogaster, Caenorhabditis elegans, and mice. However, Maf1 -/- mice are lean as increased lipogenesis is counterbalanced by futile pre-tRNA synthesis and degradation, resulting in increased energy expenditure. We compared Chow-fed Maf1 -/- mice with Chow- or High Fat (HF)-fed Maf1 hep-/- mice that lack MAF1 specifically in hepatocytes. Unlike Maf1 -/- mice, Maf1 hep-/- mice become heavier and fattier than control mice with old age and much earlier under a HF diet. Liver ChIPseq, RNAseq and proteomics analyses indicate increased Pol III occupancy at Pol III genes, very few differences in mRNA accumulation, and protein accumulation changes consistent with increased lipogenesis. Futile pre-tRNA synthesis and degradation in the liver, as likely occurs in Maf1 hep-/- mice, thus seems insufficient to counteract increased lipogenesis. Indeed, RNAseq and metabolite profiling indicate that liver phenotypes of Maf1 -/- mice are strongly influenced by systemic inter-organ communication. Among common changes in the three phenotypically distinct cohorts, Angiogenin downregulation is likely linked to increased Pol III occupancy of tRNA genes in the Angiogenin promoter.
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Affiliation(s)
- Gilles Willemin
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - François Mange
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Viviane Praz
- Lausanne Genomic Technologies Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Séverine Lorrain
- Protein Analysis Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Pascal Cousin
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Catherine Roger
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Ian M. Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, United States
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Nouria Hernandez
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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5
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Gutiérrez-Santiago F, Navarro F. Transcription by the Three RNA Polymerases under the Control of the TOR Signaling Pathway in Saccharomyces cerevisiae. Biomolecules 2023; 13:biom13040642. [PMID: 37189389 DOI: 10.3390/biom13040642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/30/2023] [Accepted: 04/02/2023] [Indexed: 04/05/2023] Open
Abstract
Ribosomes are the basis for protein production, whose biogenesis is essential for cells to drive growth and proliferation. Ribosome biogenesis is highly regulated in accordance with cellular energy status and stress signals. In eukaryotic cells, response to stress signals and the production of newly-synthesized ribosomes require elements to be transcribed by the three RNA polymerases (RNA pols). Thus, cells need the tight coordination of RNA pols to adjust adequate components production for ribosome biogenesis which depends on environmental cues. This complex coordination probably occurs through a signaling pathway that links nutrient availability with transcription. Several pieces of evidence strongly support that the Target of Rapamycin (TOR) pathway, conserved among eukaryotes, influences the transcription of RNA pols through different mechanisms to ensure proper ribosome components production. This review summarizes the connection between TOR and regulatory elements for the transcription of each RNA pol in the budding yeast Saccharomyces cerevisiae. It also focuses on how TOR regulates transcription depending on external cues. Finally, it discusses the simultaneous coordination of the three RNA pols through common factors regulated by TOR and summarizes the most important similarities and differences between S. cerevisiae and mammals.
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Affiliation(s)
- Francisco Gutiérrez-Santiago
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
- Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
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6
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Ball CB, Parida M, Li M, Spector BM, Suarez GA, Meier JL, Price DH. Human Cytomegalovirus Infection Elicits Global Changes in Host Transcription by RNA Polymerases I, II, and III. Viruses 2022; 14:v14040779. [PMID: 35458509 PMCID: PMC9026722 DOI: 10.3390/v14040779] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 12/29/2022] Open
Abstract
How human cytomegalovirus (HCMV) infection impacts the transcription of the host genome remains incompletely understood. Here, we examine the global consequences of infection of primary human foreskin fibroblasts (HFFs) on transcription by RNA polymerase I, II, and III over the course of a lytic infection using PRO-Seq. The expected rapid induction of innate immune response genes is observed with specific subsets of genes exhibiting dissimilar expression kinetics. We find minimal effects on Pol II initiation, but increased rates of the release of paused Pol II into productive elongation are detected by 24 h postinfection and pronounced at late times postinfection. Pol I transcription increases during infection and we provide evidence for a potential Pol I elongation control mechanism. Pol III transcription of tRNA genes is dramatically altered, with many induced and some repressed. All effects are partially dependent on viral genome replication, suggesting a link to viral mRNA levels and/or a viral early–late or late gene product. Changes in tRNA transcription are connected to distinct alterations in the chromatin state around tRNA genes, which were probed with high-resolution DFF-ChIP. Additionally, evidence is provided that the Pol III PIC stably contacts an upstream −1 nucleosome. Finally, we compared and contrasted our HCMV data with results from published experiments with HSV-1, EBV, KSHV, and MHV68. We report disparate effects on Pol II transcription and potentially similar effects on Pol III transcription.
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Affiliation(s)
- Christopher B. Ball
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Mrutyunjaya Parida
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Ming Li
- Departments of Internal Medicine and Epidemiology, University of Iowa and Iowa City Veterans Affairs Health Care System, Iowa City, IA 52242, USA; (M.L.); (J.L.M.)
| | - Benjamin M. Spector
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Gustavo A. Suarez
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Jeffery L. Meier
- Departments of Internal Medicine and Epidemiology, University of Iowa and Iowa City Veterans Affairs Health Care System, Iowa City, IA 52242, USA; (M.L.); (J.L.M.)
| | - David H. Price
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
- Correspondence:
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7
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Abstract
RNA polymerase III (Pol III) is a large multisubunit complex conserved in all eukaryotes that plays an essential role in producing a variety of short non-coding RNAs, such as tRNA, 5S rRNA and U6 snRNA transcripts. Pol III comprises of 17 subunits in both yeast and human with a 10-subunit core and seven peripheral subunits. Because of its size and complexity, Pol III has posed a formidable challenge to structural biologists. The first atomic cryogenic electron microscopy structure of yeast Pol III leading to the canonical view was reported in 2015. Within the last few years, the optimization of endogenous extract and purification procedure and the technical and methodological advances in cryogenic electron microscopy, together allow us to have a first look at the unprecedented details of human Pol III organization. Here, we look back on the structural studies of human Pol III and discuss them in the light of our current understanding of its role in eukaryotic transcription.
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Affiliation(s)
- Qianmin Wang
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Ming Lei
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China.,State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wu
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
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8
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Structure of human RNA polymerase III elongation complex. Cell Res 2021; 31:791-800. [PMID: 33674783 PMCID: PMC8249397 DOI: 10.1038/s41422-021-00472-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/06/2021] [Indexed: 01/31/2023] Open
Abstract
RNA polymerase III (Pol III) transcribes essential structured small RNAs, such as tRNAs, 5S rRNA and U6 snRNA. The transcriptional activity of Pol III is tightly controlled and its dysregulation is associated with human diseases, such as cancer. Human Pol III has two isoforms with difference only in one of its subunits RPC7 (α and β). Despite structural studies of yeast Pol III, structure of human Pol III remains unsolved. Here, we determined the structures of 17-subunit human Pol IIIα complex in the backtracked and post-translocation states, respectively. Human Pol III contains a generally conserved catalytic core, similar to that of yeast counterpart, and structurally unique RPC3-RPC6-RPC7 heterotrimer and RPC10. The N-ribbon of TFIIS-like RPC10 docks on the RPC4-RPC5 heterodimer and the C-ribbon inserts into the funnel of Pol III in the backtracked state but is more flexible in the post-translocation state. RPC7 threads through the heterotrimer and bridges the stalk and Pol III core module. The winged helix 1 domain of RPC6 and the N-terminal region of RPC7α stabilize each other and may prevent Maf1-mediated repression of Pol III activity. The C-terminal FeS cluster of RPC6 coordinates a network of interactions that mediate core-heterotrimer contacts and stabilize Pol III. Our structural analysis sheds new light on the molecular mechanism of human Pol IIIα-specific transcriptional regulation and provides explanations for upregulated Pol III activity in RPC7α-dominant cancer cells.
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9
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Roles for the RNA polymerase III regulator MAFR-1 in regulating sperm quality in Caenorhabditis elegans. Sci Rep 2020; 10:19367. [PMID: 33168938 PMCID: PMC7652826 DOI: 10.1038/s41598-020-76423-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/27/2020] [Indexed: 11/08/2022] Open
Abstract
The negative regulator of RNA polymerase (pol) III mafr-1 has been shown to affect RNA pol III transcript abundance, lipid biosynthesis and storage, progeny output, and lifespan. We deleted mafr-1 from the Caenorhabditis elegans genome and found that animals lacking mafr-1 replicated many phenotypes from previous RNAi-based studies and discovered a new sperm-specific role. Utilizing a yeast two-hybrid assay, we discovered several novel interactors of MAFR-1 that are expressed in a sperm- and germline-enriched manner. In support of a role for MAFR-1 in the male germline, we found mafr-1 null males have smaller spermatids that are less capable in competition for fertilization; a phenotype that was dependent on RNA pol III activity. Restoration of MAFR-1 expression specifically in the germline rescued the spermatid-related phenotypes, suggesting a cell autonomous role for MAFR-1 in nematode male fertility. Based on the high degree of conservation of Maf1 activity across species, our study may inform similar roles for Maf1 and RNA pol III in mammalian male fertility.
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10
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Feng X, Tubbs A, Zhang C, Tang M, Sridharan S, Wang C, Jiang D, Su D, Zhang H, Chen Z, Nie L, Xiong Y, Huang M, Nussenzweig A, Chen J. ATR inhibition potentiates ionizing radiation-induced interferon response via cytosolic nucleic acid-sensing pathways. EMBO J 2020; 39:e104036. [PMID: 32484965 DOI: 10.15252/embj.2019104036] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 03/21/2020] [Accepted: 05/08/2020] [Indexed: 12/20/2022] Open
Abstract
Mechanistic understanding of how ionizing radiation induces type I interferon signaling and how to amplify this signaling module should help to maximize the efficacy of radiotherapy. In the current study, we report that inhibitors of the DNA damage response kinase ATR can significantly potentiate ionizing radiation-induced innate immune responses. Using a series of mammalian knockout cell lines, we demonstrate that, surprisingly, both the cGAS/STING-dependent DNA-sensing pathway and the MAVS-dependent RNA-sensing pathway are responsible for type I interferon signaling induced by ionizing radiation in the presence or absence of ATR inhibitors. The relative contributions of these two pathways in type I interferon signaling depend on cell type and/or genetic background. We propose that DNA damage-elicited double-strand DNA breaks releases DNA fragments, which may either activate the cGAS/STING-dependent pathway or-especially in the case of AT-rich DNA sequences-be transcribed and initiate MAVS-dependent RNA sensing and signaling. Together, our results suggest the involvement of two distinct pathways in type I interferon signaling upon DNA damage. Moreover, radiation plus ATR inhibition may be a promising new combination therapy against cancer.
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Affiliation(s)
- Xu Feng
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Anthony Tubbs
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Chunchao Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mengfan Tang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sriram Sridharan
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Chao Wang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dadi Jiang
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dan Su
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Huimin Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Zhen Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Litong Nie
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yun Xiong
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Min Huang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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11
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Wang X, Rusin A, Walkey CJ, Lin JJ, Johnson DL. The RNA polymerase III repressor MAF1 is regulated by ubiquitin-dependent proteasome degradation and modulates cancer drug resistance and apoptosis. J Biol Chem 2019; 294:19255-19268. [PMID: 31645432 DOI: 10.1074/jbc.ra119.008849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/01/2019] [Indexed: 01/03/2023] Open
Abstract
MAF1 homolog, negative regulator of RNA polymerase III (MAF1) is a key repressor of RNA polymerase (pol) III-dependent transcription and functions as a tumor suppressor. Its expression is frequently down-regulated in primary human hepatocellular carcinomas (HCCs). However, this reduction in MAF1 protein levels does not correlate with its transcript levels, indicating that MAF1 is regulated post-transcriptionally. Here, we demonstrate that MAF1 is a labile protein whose levels are regulated through the ubiquitin-dependent proteasome pathway. We found that MAF1 ubiquitination is enhanced upon mTOR complex 1 (TORC1)-mediated phosphorylation at Ser-75. Moreover, we observed that the E3 ubiquitin ligase cullin 2 (CUL2) critically regulates MAF1 ubiquitination and controls its stability and subsequent RNA pol III-dependent transcription. Analysis of the phenotypic consequences of modulating either CUL2 or MAF1 protein expression revealed changes in actin cytoskeleton reorganization and altered sensitivity to doxorubicin-induced apoptosis. Repression of RNA pol III-dependent transcription by chemical inhibition or knockdown of BRF1 RNA pol III transcription initiation factor subunit (BRF1) enhanced HCC cell sensitivity to doxorubicin, suggesting that MAF1 regulates doxorubicin resistance in HCC by controlling RNA pol III-dependent transcription. Together, our results identify the ubiquitin proteasome pathway and CUL2 as important regulators of MAF1 levels. They suggest that decreases in MAF1 protein underlie chemoresistance in HCC and perhaps other cancers and point to an important role for MAF1 and RNA pol III-mediated transcription in chemosensitivity and apoptosis.
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Affiliation(s)
- Xianlong Wang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Aleksandra Rusin
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Christopher J Walkey
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | | | - Deborah L Johnson
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
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12
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Ciesla M, Skowronek E, Boguta M. Function of TFIIIC, RNA polymerase III initiation factor, in activation and repression of tRNA gene transcription. Nucleic Acids Res 2019; 46:9444-9455. [PMID: 30053100 PMCID: PMC6182151 DOI: 10.1093/nar/gky656] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/10/2018] [Indexed: 01/09/2023] Open
Abstract
Transcription of transfer RNA genes by RNA polymerase III (Pol III) is controlled by general factors, TFIIIB and TFIIIC, and a negative regulator, Maf1. Here we report the interplay between TFIIIC and Maf1 in controlling Pol III activity upon the physiological switch of yeast from fermentation to respiration. TFIIIC directly competes with Pol III for chromatin occupancy as demonstrated by inversely correlated tDNA binding. The association of TFIIIC with tDNA was stronger under unfavorable respiratory conditions and in the presence of Maf1. Induction of tDNA transcription by glucose-activated protein kinase A (PKA) was correlated with the down-regulation of TFIIIC occupancy on tDNA. The conditions that activate the PKA signaling pathway promoted the binding of TFIIIB subunits, Brf1 and Bdp1, with tDNA, but decreased their interaction with TFIIIC. Association of Brf1 and Bdp1 with TFIIIC was much stronger under repressive conditions, potentially restricting TFIIIB recruitment to tDNA and preventing Pol III recruitment. Altogether, we propose a model in which, depending on growth conditions, TFIIIC promotes activation or repression of tDNA transcription.
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Affiliation(s)
- Malgorzata Ciesla
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Ewa Skowronek
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Magdalena Boguta
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
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13
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Herrera MC, Chymkowitch P, Robertson JM, Eriksson J, Bøe SO, Alseth I, Enserink JM. Cdk1 gates cell cycle-dependent tRNA synthesis by regulating RNA polymerase III activity. Nucleic Acids Res 2019; 46:11698-11711. [PMID: 30247619 PMCID: PMC6294503 DOI: 10.1093/nar/gky846] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/10/2018] [Indexed: 01/14/2023] Open
Abstract
tRNA genes are transcribed by RNA polymerase III (RNAPIII). During recent years it has become clear that RNAPIII activity is strictly regulated by the cell in response to environmental cues and the homeostatic status of the cell. However, the molecular mechanisms that control RNAPIII activity to regulate the amplitude of tDNA transcription in normally cycling cells are not well understood. Here, we show that tRNA levels fluctuate during the cell cycle and reveal an underlying molecular mechanism. The cyclin Clb5 recruits the cyclin dependent kinase Cdk1 to tRNA genes to boost tDNA transcription during late S phase. At tDNA genes, Cdk1 promotes the recruitment of TFIIIC, stimulates the interaction between TFIIIB and TFIIIC, and increases the dynamics of RNA polymerase III in vivo. Furthermore, we identified Bdp1 as a putative Cdk1 substrate in this process. Preventing Bdp1 phosphorylation prevented cell cycle-dependent recruitment of TFIIIC and abolished the cell cycle-dependent increase in tDNA transcription. Our findings demonstrate that under optimal growth conditions Cdk1 gates tRNA synthesis in S phase by regulating the RNAPIII machinery, revealing a direct link between the cell cycle and RNAPIII activity.
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Affiliation(s)
- Maria C Herrera
- Department of Molecular Cell Biology, Institute for Cancer Research, the Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway.,Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,The Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0371, Norway
| | - Pierre Chymkowitch
- Department of Molecular Cell Biology, Institute for Cancer Research, the Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway
| | - Joseph M Robertson
- Department of Molecular Cell Biology, Institute for Cancer Research, the Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway.,Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Jens Eriksson
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Stig Ove Bøe
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Ingrun Alseth
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Jorrit M Enserink
- Department of Molecular Cell Biology, Institute for Cancer Research, the Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway.,Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,The Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0371, Norway
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14
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Advani VM, Ivanov P. Translational Control under Stress: Reshaping the Translatome. Bioessays 2019; 41:e1900009. [PMID: 31026340 PMCID: PMC6541386 DOI: 10.1002/bies.201900009] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/06/2019] [Indexed: 01/01/2023]
Abstract
Adequate reprogramming of cellular metabolism in response to stresses or suboptimal growth conditions involves a myriad of coordinated changes that serve to promote cell survival. As protein synthesis is an energetically expensive process, its regulation under stress is of critical importance. Reprogramming of messenger RNA (mRNA) translation involves well-understood stress-activated kinases that target components of translation initiation machinery, resulting in the robust inhibition of general translation and promotion of the translation of stress-responsive proteins. Translational arrest of mRNAs also results in the accumulation of transcripts in cytoplasmic foci called stress granules. Recent studies focus on the key roles of transfer RNA (tRNA) in stress-induced translational reprogramming. These include stress-specific regulation of tRNA pools, codon-biased translation influenced by tRNA modifications, tRNA miscoding, and tRNA cleavage. In combination, signal transduction pathways and tRNA metabolism changes regulate translation during stress, resulting in adaptation and cell survival. This review examines molecular mechanisms that regulate protein synthesis in response to stress.
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Affiliation(s)
- Vivek M. Advani
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- The Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts, United States of America
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15
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Szatkowska R, Garcia-Albornoz M, Roszkowska K, Holman SW, Furmanek E, Hubbard SJ, Beynon RJ, Adamczyk M. Glycolytic flux in Saccharomyces cerevisiae is dependent on RNA polymerase III and its negative regulator Maf1. Biochem J 2019; 476:1053-1082. [PMID: 30885983 PMCID: PMC6448137 DOI: 10.1042/bcj20180701] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 03/11/2019] [Accepted: 03/15/2019] [Indexed: 02/07/2023]
Abstract
Protein biosynthesis is energetically costly, is tightly regulated and is coupled to stress conditions including glucose deprivation. RNA polymerase III (RNAP III)-driven transcription of tDNA genes for production of tRNAs is a key element in efficient protein biosynthesis. Here we present an analysis of the effects of altered RNAP III activity on the Saccharomyces cerevisiae proteome and metabolism under glucose-rich conditions. We show for the first time that RNAP III is tightly coupled to the glycolytic system at the molecular systems level. Decreased RNAP III activity or the absence of the RNAP III negative regulator, Maf1 elicit broad changes in the abundance profiles of enzymes engaged in fundamental metabolism in S. cerevisiae In a mutant compromised in RNAP III activity, there is a repartitioning towards amino acids synthesis de novo at the expense of glycolytic throughput. Conversely, cells lacking Maf1 protein have greater potential for glycolytic flux.
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Affiliation(s)
- Roza Szatkowska
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | - Manuel Garcia-Albornoz
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, U.K
| | - Katarzyna Roszkowska
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | - Stephen W Holman
- Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, U.K
| | - Emil Furmanek
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | - Simon J Hubbard
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, U.K
| | - Robert J Beynon
- Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, U.K
| | - Malgorzata Adamczyk
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
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16
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Ahn CS, Lee DH, Pai HS. Characterization of Maf1 in Arabidopsis: function under stress conditions and regulation by the TOR signaling pathway. PLANTA 2019; 249:527-542. [PMID: 30293201 DOI: 10.1007/s00425-018-3024-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 09/30/2018] [Indexed: 06/08/2023]
Abstract
Maf1 repressor activity is critical for plant survival during environmental stresses, and is regulated by its phosphorylation/dephosphorylation through the activity of TOR and PP4/PP2A phosphatases. Maf1 is a global repressor of RNA polymerase III (Pol III), and is conserved in eukaryotes. Pol III synthesizes small RNAs, 5S rRNA, and tRNAs that are essential for protein translation and cell growth. Maf1 is a phosphoprotein and dephosphorylation of Maf1 promotes its repressor activity in yeast and mammals. Plant Maf1 was identified in citrus plants as a canker elicitor-binding protein, and citrus Maf1 represses cell growth associated with canker development. However, functions of plant Maf1 under diverse stress conditions and its regulation by the target of rapamycin (TOR) signaling components are poorly understood. In this study, the Arabidopsis maf1 mutants were more susceptible to diverse stresses and treatment with the TOR inhibitor Torin-1 than wild-type plants. The maf1 mutants expressed higher levels of Maf1 target RNAs, including 5S rRNA and pre-tRNAs in leaf cells, supporting Pol III repressor activity of Arabidopsis Maf1. Cellular stresses and Torin-1 treatment induced dephosphorylation of Maf1, suggesting Maf1 activation under diverse stress conditions. TOR silencing also stimulated Maf1 dephosphorylation, while silencing of catalytic subunit genes of PP4 and PP2A repressed it. Thus, TOR kinase and PP4/PP2A phosphatases appeared to oppositely modulate the Maf1 phosphorylation status. TOR silencing decreased the abundance of the target RNAs, while silencing of the PP4 and PP2A subunit genes increased it, supporting the positive correlation between Maf1 dephosphorylation and its repressor activity. Taken together, these results suggest that repressor activity of Maf1, regulated by the TOR signaling pathway, is critical for plant cell survival during environmental stresses.
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Affiliation(s)
- Chang Sook Ahn
- Department of Systems Biology, Yonsei University, Seoul, 03722, Korea
- Future Technology Research Center, Corporate R&D, LG Chem/LG Science Park, Seoul, 07796, Korea
| | - Du-Hwa Lee
- Department of Systems Biology, Yonsei University, Seoul, 03722, Korea
| | - Hyun-Sook Pai
- Department of Systems Biology, Yonsei University, Seoul, 03722, Korea.
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17
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Wang Z, Wu C, Aslanian A, Yates JR, Hunter T. Defective RNA polymerase III is negatively regulated by the SUMO-Ubiquitin-Cdc48 pathway. eLife 2018; 7:35447. [PMID: 30192228 PMCID: PMC6128692 DOI: 10.7554/elife.35447] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/21/2018] [Indexed: 12/26/2022] Open
Abstract
Transcription by RNA polymerase III (Pol III) is an essential cellular process, and mutations in Pol III can cause neurodegenerative disease in humans. However, in contrast to Pol II transcription, which has been extensively studied, the knowledge of how Pol III is regulated is very limited. We report here that in budding yeast, Saccharomyces cerevisiae, Pol III is negatively regulated by the Small Ubiquitin-like MOdifier (SUMO), an essential post-translational modification pathway. Besides sumoylation, Pol III is also targeted by ubiquitylation and the Cdc48/p97 segregase; these three processes likely act in a sequential manner and eventually lead to proteasomal degradation of Pol III subunits, thereby repressing Pol III transcription. This study not only uncovered a regulatory mechanism for Pol III, but also suggests that the SUMO and ubiquitin modification pathways and the Cdc48/p97 segregase can be potential therapeutic targets for Pol III-related human diseases.
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Affiliation(s)
- Zheng Wang
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
| | - Catherine Wu
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
| | - Aaron Aslanian
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, United States.,The Scripps Research Institute, La Jolla, United States
| | - John R Yates
- The Scripps Research Institute, La Jolla, United States
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
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18
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Chen CY, Lanz RB, Walkey CJ, Chang WH, Lu W, Johnson DL. Maf1 and Repression of RNA Polymerase III-Mediated Transcription Drive Adipocyte Differentiation. Cell Rep 2018; 24:1852-1864. [PMID: 30110641 PMCID: PMC6138453 DOI: 10.1016/j.celrep.2018.07.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/05/2018] [Accepted: 07/12/2018] [Indexed: 12/11/2022] Open
Abstract
RNA polymerase (pol) III transcribes a variety of small untranslated RNAs involved in transcription, RNA processing, and translation. RNA pol III and its components are altered in various human developmental disorders, yet their roles in cell fate determination and development are poorly understood. Here we demonstrate that Maf1, a transcriptional repressor, promotes induction of mouse embryonic stem cells (mESCs) into mesoderm. Reduced Maf1 expression in mESCs and preadipocytes impairs adipogenesis, while ectopic Maf1 expression in Maf1-deficient cells enhances differentiation. RNA pol III repression by chemical inhibition or knockdown of Brf1 promotes adipogenesis. Altered RNA pol III-dependent transcription produces select changes in mRNAs with a significant enrichment of adipogenic gene signatures. Furthermore, RNA pol III-mediated transcription positively regulates long non-coding RNA H19 and Wnt6 expression, established adipogenesis inhibitors. Together, these studies reveal an important and unexpected function for RNA pol III-mediated transcription and Maf1 in mesoderm induction and adipocyte differentiation.
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Affiliation(s)
- Chun-Yuan Chen
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, CA, USA; Department of Molecular and Cellular Biology and the Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Rainer B Lanz
- Department of Molecular and Cellular Biology and the Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Christopher J Walkey
- Department of Molecular and Cellular Biology and the Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Wen-Hsuan Chang
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California, Los Angeles, CA, USA
| | - Wange Lu
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, CA, USA; Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California, Los Angeles, CA, USA
| | - Deborah L Johnson
- Department of Molecular and Cellular Biology and the Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA.
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19
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Graczyk D, Cieśla M, Boguta M. Regulation of tRNA synthesis by the general transcription factors of RNA polymerase III - TFIIIB and TFIIIC, and by the MAF1 protein. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:320-329. [DOI: 10.1016/j.bbagrm.2018.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 01/20/2018] [Accepted: 01/21/2018] [Indexed: 01/03/2023]
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20
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Arimbasseri GA. Interactions between RNAP III transcription machinery and tRNA processing factors. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:354-360. [PMID: 29428193 DOI: 10.1016/j.bbagrm.2018.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 10/18/2022]
Abstract
Eukaryotes have at least three nuclear RNA polymerases to carry out transcription. While RNA polymerases I and II are responsible for ribosomal RNA transcription and messenger RNA transcription, respectively, RNA Polymerase III transcribes approximately up to 300 nt long noncoding RNAs, including tRNA. For all three RNAPs, the nascent transcripts generated undergo extensive post-transcriptional processing. Transcription of mRNAs by RNAP II and their processing are coupled with the aid of the C-terminal domain of the RNAP II. RNAP I transcription and the processing of its transcripts are co-localized to the nucleolus and to some extent, rRNA processing occurs co-transcriptionally. Here, I review the current evidence for the interaction between tRNA processing factors and RNA polymerase III. These interactions include the moonlighting functions of tRNA processing factors in RNAP III transcription and the indirect effect of tRNA transcription levels on tRNA modification machinery.
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Affiliation(s)
- G Aneeshkumar Arimbasseri
- Molecular Genetics Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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21
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Zhang S, Li X, Wang HY, Steven Zheng XF. Beyond regulation of pol III: Role of MAF1 in growth, metabolism, aging and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:338-343. [PMID: 29407795 DOI: 10.1016/j.bbagrm.2018.01.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 01/24/2018] [Accepted: 01/28/2018] [Indexed: 11/24/2022]
Abstract
MAF1 was discovered as a master repressor of Pol III-dependent transcription in response to diverse extracellular signals, including growth factor, nutrient and stress. It is regulated through posttranslational mechanisms such as phosphorylation. A prominent upstream regulator of MAF1 is the mechanistic target of rapamycin (mTOR) pathway. mTOR kinase directly phosphorylates MAF1, controlling its localization and transcriptional activity. In mammals, MAF1 has also been shown to regulate Pol I- and Pol II-dependent transcription. Interestingly, MAF1 modulates Pol II activity both as a repressor and activator, depending on specific target genes, to impact on cellular growth and metabolism. While MAF1 represses genes such as TATA-binding protein (TBP) and fatty acid synthase (FASN), it activates the expression of PTEN, a major tumor suppressor and an inhibitor of the mTOR signaling. Increasing evidence indicates that MAF1 plays an important role in different aspects of normal physiology, lifespan and oncogenesis. Here we will review the current knowledge on MAF1 in growth, metabolism, aging and cancer. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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Affiliation(s)
- Shanshan Zhang
- State Key Laboratory of Oncology in South China, and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Xiaoxing Li
- State Key Laboratory of Oncology in South China, and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Hui-Yun Wang
- State Key Laboratory of Oncology in South China, and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Rutgers Cancer Institute of New Jersey and Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08903, USA
| | - X F Steven Zheng
- State Key Laboratory of Oncology in South China, and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Rutgers Cancer Institute of New Jersey and Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08903, USA.
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22
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Willis IM, Moir RD. Signaling to and from the RNA Polymerase III Transcription and Processing Machinery. Annu Rev Biochem 2018; 87:75-100. [PMID: 29328783 DOI: 10.1146/annurev-biochem-062917-012624] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA polymerase (Pol) III has a specialized role in transcribing the most abundant RNAs in eukaryotic cells, transfer RNAs (tRNAs), along with other ubiquitous small noncoding RNAs, many of which have functions related to the ribosome and protein synthesis. The high energetic cost of producing these RNAs and their central role in protein synthesis underlie the robust regulation of Pol III transcription in response to nutrients and stress by growth regulatory pathways. Downstream of Pol III, signaling impacts posttranscriptional processes affecting tRNA function in translation and tRNA cleavage into smaller fragments that are increasingly attributed with novel cellular activities. In this review, we consider how nutrients and stress control Pol III transcription via its factors and its negative regulator, Maf1. We highlight recent work showing that the composition of the tRNA population and the function of individual tRNAs is dynamically controlled and that unrestrained Pol III transcription can reprogram central metabolic pathways.
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Affiliation(s)
- Ian M Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA; , .,Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA; ,
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23
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Leśniewska E, Boguta M. Novel layers of RNA polymerase III control affecting tRNA gene transcription in eukaryotes. Open Biol 2017; 7:rsob.170001. [PMID: 28228471 PMCID: PMC5356446 DOI: 10.1098/rsob.170001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 01/31/2017] [Indexed: 12/20/2022] Open
Abstract
RNA polymerase III (Pol III) transcribes a limited set of short genes in eukaryotes producing abundant small RNAs, mostly tRNA. The originally defined yeast Pol III transcriptome appears to be expanding owing to the application of new methods. Also, several factors required for assembly and nuclear import of Pol III complex have been identified recently. Models of Pol III based on cryo-electron microscopy reconstructions of distinct Pol III conformations reveal unique features distinguishing Pol III from other polymerases. Novel concepts concerning Pol III functioning involve recruitment of general Pol III-specific transcription factors and distinctive mechanisms of transcription initiation, elongation and termination. Despite the short length of Pol III transcription units, mapping of transcriptionally active Pol III with nucleotide resolution has revealed strikingly uneven polymerase distribution along all genes. This may be related, at least in part, to the transcription factors bound at the internal promoter regions. Pol III uses also a specific negative regulator, Maf1, which binds to polymerase under stress conditions; however, a subset of Pol III genes is not controlled by Maf1. Among other RNA polymerases, Pol III machinery represents unique features related to a short transcript length and high transcription efficiency.
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Affiliation(s)
- Ewa Leśniewska
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Magdalena Boguta
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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24
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Soprano AS, Smetana JHC, Benedetti CE. Regulation of tRNA biogenesis in plants and its link to plant growth and response to pathogens. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1861:344-353. [PMID: 29222070 DOI: 10.1016/j.bbagrm.2017.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/29/2017] [Accepted: 12/03/2017] [Indexed: 12/23/2022]
Abstract
The field of tRNA biology, encompassing the functional and structural complexity of tRNAs, has fascinated scientists over the years and is continuously growing. Besides their fundamental role in protein translation, new evidence indicates that tRNA-derived molecules also regulate gene expression and protein synthesis in all domains of life. This review highlights some of the recent findings linking tRNA transcription and modification with plant cell growth and response to pathogens. In fact, mutations in proteins directly involved in tRNA synthesis and modification most often lead to pleiotropic effects on plant growth and immunity. As plants need to optimize and balance their energy and nutrient resources towards growth and defense, regulatory pathways that play a central role in integrating tRNA transcription and protein translation with cell growth control and organ development, such as the auxin-TOR signaling pathway, also influence the plant immune response against pathogens. As a consequence, distinct pathogens employ an array of effector molecules including tRNA fragments to target such regulatory pathways to exploit the plant's translational capacity, gain access to nutrients and evade defenses. An example includes the RNA polymerase III repressor MAF1, a conserved component of the TOR signaling pathway that controls ribosome biogenesis and tRNA synthesis required for plant growth and which is targeted by a pathogen effector molecule to promote disease. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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Affiliation(s)
- Adriana Santos Soprano
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, SP, Brazil
| | - Juliana Helena Costa Smetana
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, SP, Brazil
| | - Celso Eduardo Benedetti
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, SP, Brazil.
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25
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Soprano AS, Giuseppe POD, Shimo HM, Lima TB, Batista FAH, Righetto GL, Pereira JGDC, Granato DC, Nascimento AFZ, Gozzo FC, de Oliveira PSL, Figueira ACM, Smetana JHC, Paes Leme AF, Murakami MT, Benedetti CE. Crystal Structure and Regulation of the Citrus Pol III Repressor MAF1 by Auxin and Phosphorylation. Structure 2017; 25:1360-1370.e4. [PMID: 28781084 DOI: 10.1016/j.str.2017.07.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/16/2017] [Accepted: 07/06/2017] [Indexed: 10/25/2022]
Abstract
MAF1 is the main RNA polymerase (Pol) III repressor that controls cell growth in eukaryotes. The Citrus ortholog, CsMAF1, was shown to restrict cell growth in citrus canker disease but its role in plant development and disease is still unclear. We solved the crystal structure of the globular core of CsMAF1, which reveals additional structural elements compared with the previously available structure of hMAF1, and explored the dynamics of its flexible regions not present in the structure. CsMAF1 accumulated in the nucleolus upon leaf excision, and this translocation was inhibited by auxin and by mutation of the PKA phosphorylation site, S45, to aspartate. Additionally, mTOR phosphorylated recombinant CsMAF1 and the mTOR inhibitor AZD8055 blocked canker formation in normal but not CsMAF1-silenced plants. These results indicate that the role of TOR on cell growth induced by Xanthomonas citri depends on CsMAF1 and that auxin controls CsMAF1 interaction with Pol III in citrus.
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Affiliation(s)
- Adriana Santos Soprano
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Priscila Oliveira de Giuseppe
- Brazilian Bioethanol Science and Technology Laboratory (CTBE), Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Hugo Massayoshi Shimo
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Tatiani Brenelli Lima
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil; Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil
| | - Fernanda Aparecida Heleno Batista
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Germanna Lima Righetto
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - José Geraldo de Carvalho Pereira
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Daniela Campos Granato
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Andrey Fabricio Ziem Nascimento
- XALOC Beamline, Experiments Division, ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Barcelona, Spain; Structural Biology, Molecular Biology Institute of Barcelona (IBMB-CSIC), Carrer Baldiri Reixac 15, 3 A17, 08028 Barcelona, Spain
| | - Fabio Cesar Gozzo
- Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil
| | - Paulo Sérgio Lopes de Oliveira
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Ana Carolina Migliorini Figueira
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Juliana Helena Costa Smetana
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Adriana Franco Paes Leme
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Mario Tyago Murakami
- Brazilian Bioethanol Science and Technology Laboratory (CTBE), Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil
| | - Celso Eduardo Benedetti
- Brazilian Nacional Biosciences Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-100 Campinas, São Paulo, Brazil.
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TORC1-dependent sumoylation of Rpc82 promotes RNA polymerase III assembly and activity. Proc Natl Acad Sci U S A 2017; 114:1039-1044. [PMID: 28096404 DOI: 10.1073/pnas.1615093114] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Maintaining cellular homeostasis under changing nutrient conditions is essential for the growth and development of all organisms. The mechanisms that maintain homeostasis upon loss of nutrient supply are not well understood. By mapping the SUMO proteome in Saccharomyces cerevisiae, we discovered a specific set of differentially sumoylated proteins mainly involved in transcription. RNA polymerase III (RNAPIII) components, including Rpc53, Rpc82, and Ret1, are particularly prominent nutrient-dependent SUMO targets. Nitrogen starvation, as well as direct inhibition of the master nutrient response regulator target of rapamycin complex 1 (TORC1), results in rapid desumoylation of these proteins, which is reflected by loss of SUMO at tRNA genes. TORC1-dependent sumoylation of Rpc82 in particular is required for robust tRNA transcription. Mechanistically, sumoylation of Rpc82 is important for assembly of the RNAPIII holoenzyme and recruitment of Rpc82 to tRNA genes. In conclusion, our data show that TORC1-dependent sumoylation of Rpc82 bolsters the transcriptional capacity of RNAPIII under optimal growth conditions.
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Pradhan A, Hammerquist AM, Khanna A, Curran SP. The C-Box Region of MAF1 Regulates Transcriptional Activity and Protein Stability. J Mol Biol 2016; 429:192-207. [PMID: 27986570 DOI: 10.1016/j.jmb.2016.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 11/15/2016] [Accepted: 12/08/2016] [Indexed: 12/26/2022]
Abstract
MAF1 is a conserved negative regulator of RNA polymerase (pol) III and intracellular lipid homeostasis across species. Here, we show that the MAF1 C-box region negatively regulates its activity. Mutations in Caenorhabditis elegans mafr-1 that truncate the C-box retain the ability to inhibit the transcription of RNA pol III targets, reduce lipid biogenesis, and lower reproductive output. In human cells, C-box deletion of MAF1 leads to increased MAF1 nuclear localization and enhanced repression of ACC1 and FASN, but with impaired repression of RNA pol III targets. Surprisingly, C-box mutations render MAF1 insensitive to rapamycin, further defining a regulatory role for this region. Two MAF1 species, MAF1L and MAF1S, are regulated by the C-box YSY motif, which, when mutated, alters species stoichiometry and proteasome-dependent turnover of nuclear MAF1. Our results reveal a role for the C-box region as a critical determinant of MAF1 stability, activity, and response to cellular stress.
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Affiliation(s)
- Ajay Pradhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Amy M Hammerquist
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Akshat Khanna
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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28
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Romero-Meza G, Vélez-Ramírez DE, Florencio-Martínez LE, Román-Carraro FC, Manning-Cela R, Hernández-Rivas R, Martínez-Calvillo S. Maf1 is a negative regulator of transcription in Trypanosoma brucei. Mol Microbiol 2016; 103:452-468. [PMID: 27802583 DOI: 10.1111/mmi.13568] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2016] [Indexed: 11/29/2022]
Abstract
RNA polymerase III (Pol III) produces small RNA molecules that play essential roles in mRNA processing and translation. Maf1, originally described as a negative regulator of Pol III transcription, has been studied from yeast to human. Here we characterized Maf1 in the parasitic protozoa Trypanosoma brucei (TbMaf1), representing the first report to analyse Maf1 in an early-diverged eukaryote. While Maf1 is generally encoded by a single-copy gene, the T. brucei genome contains two almost identical TbMaf1 genes. The TbMaf1 protein has the three conserved sequences and is predicted to fold into a globular structure. Unlike in yeast, TbMaf1 localizes to the nucleus in procyclic forms of T. brucei under normal growth conditions. Cell lines that either downregulate or overexpress TbMaf1 were generated, and growth curve analysis with them suggested that TbMaf1 participates in the regulation of cell growth of T. brucei. Nuclear run-on and chromatin immunoprecipitation analyses demonstrated that TbMaf1 represses Pol III transcription of tRNA and U2 snRNA genes by associating with their promoters. Interestingly, 5S rRNA levels do not change after TbMaf1 ablation or overexpression. Notably, our data also revealed that TbMaf1 regulates Pol I transcription of procyclin gene and Pol II transcription of SL RNA genes.
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Affiliation(s)
- Gabriela Romero-Meza
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México.,Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF, 07360, México
| | - Daniel E Vélez-Ramírez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México
| | - Luis E Florencio-Martínez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México
| | - Fiordaliso C Román-Carraro
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México
| | - Rebeca Manning-Cela
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF, 07360, México
| | - Rosaura Hernández-Rivas
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF, 07360, México
| | - Santiago Martínez-Calvillo
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. De los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP, 54090, México
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Turowski TW, Leśniewska E, Delan-Forino C, Sayou C, Boguta M, Tollervey D. Global analysis of transcriptionally engaged yeast RNA polymerase III reveals extended tRNA transcripts. Genome Res 2016; 26:933-44. [PMID: 27206856 PMCID: PMC4937561 DOI: 10.1101/gr.205492.116] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/20/2016] [Indexed: 01/25/2023]
Abstract
RNA polymerase III (RNAPIII) synthesizes a range of highly abundant small stable RNAs, principally pre-tRNAs. Here we report the genome-wide analysis of nascent transcripts attached to RNAPIII under permissive and restrictive growth conditions. This revealed strikingly uneven polymerase distributions across transcription units, generally with a predominant 5' peak. This peak was higher for more heavily transcribed genes, suggesting that initiation site clearance is rate-limiting during RNAPIII transcription. Down-regulation of RNAPIII transcription under stress conditions was found to be uneven; a subset of tRNA genes showed low response to nutrient shift or loss of the major transcription regulator Maf1, suggesting potential "housekeeping" roles. Many tRNA genes were found to generate long, 3'-extended forms due to read-through of the canonical poly(U) terminators. The degree of read-through was anti-correlated with the density of U-residues in the nascent tRNA, and multiple, functional terminators can be located far downstream. The steady-state levels of 3'-extended pre-tRNA transcripts are low, apparently due to targeting by the nuclear surveillance machinery, especially the RNA binding protein Nab2, cofactors for the nuclear exosome, and the 5'-exonuclease Rat1.
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Affiliation(s)
- Tomasz W Turowski
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland; Institute of Biotechnology, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
| | - Ewa Leśniewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Clementine Delan-Forino
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland
| | - Camille Sayou
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland
| | - Magdalena Boguta
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland
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30
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Li Y, Tsang CK, Wang S, Li X, Yang Y, Fu L, Huang W, Li M, Wang H, Zheng XS. MAF1 suppresses AKT-mTOR signaling and liver cancer through activation of PTEN transcription. Hepatology 2016; 63:1928-42. [PMID: 26910647 PMCID: PMC5021206 DOI: 10.1002/hep.28507] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/17/2016] [Indexed: 12/12/2022]
Abstract
UNLABELLED The phosphatidylinositol 3-kinase/phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase/protein kinase B/mammalian target of rapamycin (PI3K-PTEN-AKT-mTOR) pathway is a central controller of cell growth and a key driver for human cancer. MAF1 is an mTOR downstream effector and transcriptional repressor of ribosomal and transfer RNA genes. MAF1 expression is markedly reduced in hepatocellular carcinomas, which is correlated with disease progression and poor prognosis. Consistently, MAF1 displays tumor-suppressor activity toward in vitro and in vivo cancer models. Surprisingly, blocking the synthesis of ribosomal and transfer RNAs is insufficient to account for MAF1's tumor-suppressor function. Instead, MAF1 down-regulation paradoxically leads to activation of AKT-mTOR signaling, which is mediated by decreased PTEN expression. MAF1 binds to the PTEN promoter, enhancing PTEN promoter acetylation and activity. CONCLUSION In contrast to its canonical function as a transcriptional repressor, MAF1 can also act as a transcriptional activator for PTEN, which is important for MAF1's tumor-suppressor function. These results have implications in disease staging, prognostic prediction, and AKT-mTOR-targeted therapy in liver cancer. (Hepatology 2016;63:1928-1942).
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Affiliation(s)
- Yue Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Chi Kwan Tsang
- Rutgers Cancer Institute of New Jersey and Department of Pharmacology, Robert Wood Johnson Medical School, Rutgersthe State University of New JerseyNew BrunswickNJ
| | - Suihai Wang
- State Key Laboratory of Organ Failure Research, Institute of Antibody Engineering, School of BiotechnologySouthern Medical UniversityGuangzhouChina
| | - Xiao‐Xing Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Yang Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Liwu Fu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Wenlin Huang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Ming Li
- State Key Laboratory of Organ Failure Research, Institute of Antibody Engineering, School of BiotechnologySouthern Medical UniversityGuangzhouChina
| | - Hui‐Yun Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina,Rutgers Cancer Institute of New Jersey and Department of Pharmacology, Robert Wood Johnson Medical School, Rutgersthe State University of New JerseyNew BrunswickNJ
| | - X.F. Steven Zheng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina,Rutgers Cancer Institute of New Jersey and Department of Pharmacology, Robert Wood Johnson Medical School, Rutgersthe State University of New JerseyNew BrunswickNJ
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31
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Hoffmann NA, Jakobi AJ, Vorländer MK, Sachse C, Müller CW. Transcribing RNA polymerase III observed by electron cryomicroscopy. FEBS J 2016; 283:2811-9. [PMID: 27059519 PMCID: PMC5053293 DOI: 10.1111/febs.13732] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 03/26/2016] [Accepted: 04/04/2016] [Indexed: 12/21/2022]
Abstract
Electron cryomicroscopy reconstructions of elongating RNA polymerase (Pol) III at 3.9 Å resolution and of unbound Pol III (apo Pol III) in two distinct conformations at 4.6 Å and 4.7 Å resolution allow the construction of complete atomic models of Pol III and provide new functional insights into the adaption of Pol III to fulfill its specific transcription tasks.
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Affiliation(s)
- Niklas A Hoffmann
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Arjen J Jakobi
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Matthias K Vorländer
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Carsten Sachse
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Christoph W Müller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
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32
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Orioli A, Praz V, Lhôte P, Hernandez N. Human MAF1 targets and represses active RNA polymerase III genes by preventing recruitment rather than inducing long-term transcriptional arrest. Genome Res 2016; 26:624-35. [PMID: 26941251 PMCID: PMC4864463 DOI: 10.1101/gr.201400.115] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 02/24/2016] [Indexed: 12/04/2022]
Abstract
RNA polymerase III (Pol III) is tightly controlled in response to environmental cues, yet a genomic-scale picture of Pol III regulation and the role played by its repressor MAF1 is lacking. Here, we describe genome-wide studies in human fibroblasts that reveal a dynamic and gene-specific adaptation of Pol III recruitment to extracellular signals in an mTORC1-dependent manner. Repression of Pol III recruitment and transcription are tightly linked to MAF1, which selectively localizes at Pol III loci, even under serum-replete conditions, and increasingly targets transcribing Pol III in response to serum starvation. Combining Pol III binding profiles with EU-labeling and high-throughput sequencing of newly synthesized small RNAs, we show that Pol III occupancy closely reflects ongoing transcription. Our results exclude the long-term, unproductive arrest of Pol III on the DNA as a major regulatory mechanism and identify previously uncharacterized, differential coordination in Pol III binding and transcription under different growth conditions.
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Affiliation(s)
- Andrea Orioli
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Viviane Praz
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Philippe Lhôte
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nouria Hernandez
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
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33
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Carlsten JO, Zhu X, Dávila López M, Samuelsson T, Gustafsson CM. Loss of the Mediator subunit Med20 affects transcription of tRNA and other non-coding RNA genes in fission yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:339-47. [DOI: 10.1016/j.bbagrm.2015.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 12/24/2022]
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34
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Arimbasseri AG, Rijal K, Maraia RJ. Comparative overview of RNA polymerase II and III transcription cycles, with focus on RNA polymerase III termination and reinitiation. Transcription 2015; 5:e27639. [PMID: 25764110 DOI: 10.4161/trns.27369] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In eukaryotes, RNA polymerase (RNAP) III transcribes hundreds of genes for tRNAs and 5S rRNA, among others, which share similar promoters and stable transcription initiation complexes (TIC), which support rapid RNAP III recycling. In contrast, RNAP II transcribes a large number of genes with highly variable promoters and interacting factors, which exert fine regulatory control over TIC lability and modifications of RNAP II at different transitional points in the transcription cycle. We review data that illustrate a relatively smooth continuity of RNAP III initiation-elongation-termination and reinitiation toward its function to produce high levels of tRNAs and other RNAs that support growth and development.
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Affiliation(s)
- Aneeshkumar G Arimbasseri
- a Intramural Research Program; Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Institutes of Health; Bethesda, MD USA
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35
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Lee YL, Li YC, Su CH, Chiao CH, Lin IH, Hsu MT. MAF1 represses CDKN1A through a Pol III-dependent mechanism. eLife 2015; 4:e06283. [PMID: 26067234 PMCID: PMC4480132 DOI: 10.7554/elife.06283] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 06/09/2015] [Indexed: 11/24/2022] Open
Abstract
MAF1 represses Pol III-mediated transcription by interfering with TFIIIB and Pol III. Herein, we found that MAF1 knockdown induced CDKN1A transcription and chromatin looping concurrently with Pol III recruitment. Simultaneous knockdown of MAF1 with Pol III or BRF1 (subunit of TFIIIB) diminished the activation and looping effect, which indicates that recruiting Pol III was required for activation of Pol II-mediated transcription and chromatin looping. Chromatin-immunoprecipitation analysis after MAF1 knockdown indicated enhanced binding of Pol III and BRF1, as well as of CFP1, p300, and PCAF, which are factors that mediate active histone marks, along with the binding of TATA binding protein (TBP) and POLR2E to the CDKN1A promoter. Simultaneous knockdown with Pol III abolished these regulatory events. Similar results were obtained for GDF15. Our results reveal a novel mechanism by which MAF1 and Pol III regulate the activity of a protein-coding gene transcribed by Pol II. DOI:http://dx.doi.org/10.7554/eLife.06283.001 An organism's genetic material is made of segments of DNA called genes, which contain instructions to make proteins. First, copies of the DNA are made using another molecule called ribonucleic acid (RNA) in a process known as transcription. Then the RNA is used as a template to make a protein. During transcription, enzymes called RNA polymerases move along the DNA to produce the RNA copies. When a cell is actively growing it needs large quantities of new proteins to be made, and so the level of transcription is higher. However, if a cell experiences stress caused by adverse environmental conditions (e.g., high temperatures), it can conserve resources by shutting down transcription. For example, one RNA polymerase—called Pol III—makes RNA copies with the help of a protein called BRF1 and several other proteins. However, when a cell is under stress, another protein called MAF1 can interfere with transcription by binding to BRF1, which prevents it from interacting with Pol III. Previous work has suggested that MAF1 can also inhibit the activity of another RNA polymerase called Pol II, but it was not clear how this could work. Lee et al. studied the effect of MAF1 on transcription in human cells. The experiments show that MAF1 blocks the transcription of many genes that are transcribed by Pol II, including one called CDKN1A. CDKN1A is involved in regulating many important processes, including the growth of cells and cell death. Cells that produced lower amounts of MAF1 had higher levels of CDKN1A transcription, and several proteins—including Pol II, Pol III and BRF1—were more able to bind to this gene. However, this effect was not observed in cells that also produced lower levels of Pol III or BRF1, suggesting that Pol III is needed for Pol II to be able to transcribe CDKN1A. Taken together, Lee et al.'s findings suggest that MAF1 inhibits the transcription of CDKN1A, and possibly other genes transcribed by Pol II, by regulating the activity of Pol III. Further research is needed to understand the details of how this works. DOI:http://dx.doi.org/10.7554/eLife.06283.002
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Affiliation(s)
- Yu-Ling Lee
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Yuan-Ching Li
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Hsin Su
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Chun-Hui Chiao
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - I-Hsuan Lin
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Ming-Ta Hsu
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
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36
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Lee J, Moir RD, Willis IM. Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae. PLoS One 2015; 10:e0127225. [PMID: 25970584 PMCID: PMC4430316 DOI: 10.1371/journal.pone.0127225] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 04/13/2015] [Indexed: 11/19/2022] Open
Abstract
The production of ribosomes and tRNAs for protein synthesis has a high energetic cost and is under tight transcriptional control to ensure that the level of RNA synthesis is balanced with nutrient availability and the prevailing environmental conditions. In the RNA polymerase (pol) III system in yeast, nutrients and stress affect transcription through a bifurcated signaling pathway in which protein kinase A (PKA) and TORC1 activity directly or indirectly, through downstream kinases, alter the phosphorylation state and function of the Maf1 repressor and Rpc53, a TFIIF-like subunit of the polymerase. However, numerous lines of evidence suggest greater complexity in the regulatory network including the phosphoregulation of other pol III components. To address this issue, we systematically examined all 17 subunits of pol III along with the three subunits of the initiation factor TFIIIB for evidence of differential phosphorylation in response to inhibition of TORC1. A relatively high stoichiometry of phosphorylation was observed for several of these proteins and the Rpc82 subunit of the polymerase and the Bdp1 subunit of TFIIIB were found to be differentially phosphorylated. Bdp1 is phosphorylated on four major sites during exponential growth and the protein is variably dephosphorylated under conditions that inhibit tRNA gene transcription. PKA, the TORC1-regulated kinase Sch9 and protein kinase CK2 are all implicated in the phosphorylation of Bdp1. Alanine substitutions at the four phosphosites cause hyper-repression of transcription indicating that phosphorylation of Bdp1 opposes Maf1-mediated repression. The new findings suggest an integrated regulatory model for signaling events controlling pol III transcription.
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Affiliation(s)
- Jaehoon Lee
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Robyn D. Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail: (RDM); (IMW)
| | - Ian M. Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail: (RDM); (IMW)
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37
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Sanchez-Casalongue ME, Lee J, Diamond A, Shuldiner S, Moir RD, Willis IM. Differential phosphorylation of a regulatory subunit of protein kinase CK2 by target of rapamycin complex 1 signaling and the Cdc-like kinase Kns1. J Biol Chem 2015; 290:7221-33. [PMID: 25631054 DOI: 10.1074/jbc.m114.626523] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Transcriptional regulation of ribosome and tRNA synthesis plays a central role in determining protein synthetic capacity and is tightly controlled in response to nutrient availability and cellular stress. In Saccharomyces cerevisiae, the regulation of ribosome and tRNA synthesis was recently shown to involve the Cdc-like kinase Kns1 and the GSK-3 kinase Mck1. In this study, we explored additional roles for these conserved kinases in processes connected to the target of rapamycin complex 1 (TORC1). We conducted a synthetic chemical-genetic screen in a kns1Δ mck1Δ strain and identified many novel rapamycin-hypersensitive genes. Gene ontology analysis showed enrichment for TORC1-regulated processes (vesicle-mediated transport, autophagy, and regulation of cell size) and identified new connections to protein complexes including the protein kinase CK2. CK2 is considered to be a constitutively active kinase and in budding yeast, the holoenzyme comprises two regulatory subunits, Ckb1 and Ckb2, and two catalytic subunits, Cka1 and Cka2. We show that Ckb1 is differentially phosphorylated in vivo and that Kns1 mediates this phosphorylation when nutrients are limiting and under all tested stress conditions. We determined that the phosphorylation of Ckb1 does not detectably affect the stability of the CK2 holoenzyme but correlates with the reduced occupancy of Ckb1 on tRNA genes after rapamycin treatment. Thus, the differential occupancy of tRNA genes by CK2 is likely to modulate its activation of RNA polymerase III transcription. Our data suggest that TORC1, via its effector kinase Kns1, may regulate the association of CK2 with some of its substrates by phosphorylating Ckb1.
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Affiliation(s)
| | | | | | | | | | - Ian M Willis
- From the Departments of Biochemistry and Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York 10461
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38
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Affiliation(s)
- Robyn D. Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
- * E-mail: (RDM); (IMW)
| | - Ian M. Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
- * E-mail: (RDM); (IMW)
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Acker J, Nguyen NTT, Vandamme M, Tavenet A, Briand-Suleau A, Conesa C. Sub1 and Maf1, two effectors of RNA polymerase III, are involved in the yeast quiescence cycle. PLoS One 2014; 9:e114587. [PMID: 25531541 PMCID: PMC4273968 DOI: 10.1371/journal.pone.0114587] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/11/2014] [Indexed: 12/30/2022] Open
Abstract
Sub1 and Maf1 exert an opposite effect on RNA polymerase III transcription interfering with different steps of the transcription cycle. In this study, we present evidence that Sub1 and Maf1 also exhibit an opposite role on yeast chronological life span. First, cells lacking Sub1 need more time than wild type to exit from resting and this lag in re-proliferation is correlated with a delay in transcriptional reactivation. Second, our data show that the capacity of the cells to properly establish a quiescent state is impaired in the absence of Sub1 resulting in a premature death that is dependent on the Ras/PKA and Tor1/Sch9 signalling pathways. On the other hand, we show that maf1Δ cells are long-lived mutant suggesting a connection between Pol III transcription and yeast longevity.
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Affiliation(s)
- Joël Acker
- iBiTec-S CEA, FRE3377, Gif-sur-Yvette, France
- CNRS, FRE3377, Gif-sur-Yvette, France
- Université Paris-Sud, FRE3377, Gif-sur-Yvette, France
- * E-mail: (CC); (JA)
| | - Ngoc-Thuy-Trinh Nguyen
- iBiTec-S CEA, FRE3377, Gif-sur-Yvette, France
- CNRS, FRE3377, Gif-sur-Yvette, France
- Université Paris-Sud, FRE3377, Gif-sur-Yvette, France
| | - Marie Vandamme
- iBiTec-S CEA, FRE3377, Gif-sur-Yvette, France
- CNRS, FRE3377, Gif-sur-Yvette, France
- Université Paris-Sud, FRE3377, Gif-sur-Yvette, France
| | - Arounie Tavenet
- iBiTec-S CEA, FRE3377, Gif-sur-Yvette, France
- CNRS, FRE3377, Gif-sur-Yvette, France
- Université Paris-Sud, FRE3377, Gif-sur-Yvette, France
| | - Audrey Briand-Suleau
- iBiTec-S CEA, FRE3377, Gif-sur-Yvette, France
- CNRS, FRE3377, Gif-sur-Yvette, France
- Université Paris-Sud, FRE3377, Gif-sur-Yvette, France
| | - Christine Conesa
- iBiTec-S CEA, FRE3377, Gif-sur-Yvette, France
- CNRS, FRE3377, Gif-sur-Yvette, France
- Université Paris-Sud, FRE3377, Gif-sur-Yvette, France
- * E-mail: (CC); (JA)
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40
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Grewal SS. Why should cancer biologists care about tRNAs? tRNA synthesis, mRNA translation and the control of growth. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:898-907. [PMID: 25497380 DOI: 10.1016/j.bbagrm.2014.12.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/01/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
Transfer RNAs (tRNAs) are essential for mRNA translation. They are transcribed in the nucleus by RNA polymerase III and undergo many modifications before contributing to cytoplasmic protein synthesis. In this review I highlight our understanding of how tRNA biology may be linked to the regulation of mRNA translation, growth and tumorigenesis. First, I review how oncogenes and tumour suppressor signalling pathways, such as the PI3 kinase/TORC1, Ras/ERK, Myc, p53 and Rb pathways, regulate Pol III and tRNA synthesis. In several cases, this regulation contributes to cell, tissue and body growth, and has implications for our understanding of tumorigenesis. Second, I highlight some recent work, particularly in model organisms such as yeast and Drosophila, that shows how alterations in tRNA synthesis may be not only necessary, but also sufficient to drive changes in mRNA translation and growth. These effects may arise due to both absolute increases in total tRNA levels, but also changes in the relative levels of tRNAs in the overall pool. Finally, I review some recent studies that have revealed how tRNA modifications (amino acid acylation, base modifications, subcellular shuttling, and cleavage) can be regulated by growth and stress cues to selectively influence mRNA translation. Together these studies emphasize the importance of the regulation of tRNA synthesis and modification as critical control points in protein synthesis and growth. This article is part of a Special Issue entitled: Translation and Cancer.
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Affiliation(s)
- Savraj S Grewal
- Department of Biochemistry and Molecular Biology, Clark H. Smith Brain Tumour Centre, Southern Alberta Cancer Research Institute, University of Calgary, HRIC, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
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41
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Bonhoure N, Bounova G, Bernasconi D, Praz V, Lammers F, Canella D, Willis IM, Herr W, Hernandez N, Delorenzi M. Quantifying ChIP-seq data: a spiking method providing an internal reference for sample-to-sample normalization. Genome Res 2014; 24:1157-68. [PMID: 24709819 PMCID: PMC4079971 DOI: 10.1101/gr.168260.113] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) experiments are widely used to determine, within entire genomes, the occupancy sites of any protein of interest, including, for example, transcription factors, RNA polymerases, or histones with or without various modifications. In addition to allowing the determination of occupancy sites within one cell type and under one condition, this method allows, in principle, the establishment and comparison of occupancy maps in various cell types, tissues, and conditions. Such comparisons require, however, that samples be normalized. Widely used normalization methods that include a quantile normalization step perform well when factor occupancy varies at a subset of sites, but may miss uniform genome-wide increases or decreases in site occupancy. We describe a spike adjustment procedure (SAP) that, unlike commonly used normalization methods intervening at the analysis stage, entails an experimental step prior to immunoprecipitation. A constant, low amount from a single batch of chromatin of a foreign genome is added to the experimental chromatin. This "spike" chromatin then serves as an internal control to which the experimental signals can be adjusted. We show that the method improves similarity between replicates and reveals biological differences including global and largely uniform changes.
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Affiliation(s)
- Nicolas Bonhoure
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Gergana Bounova
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland; Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - David Bernasconi
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland; Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Viviane Praz
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Fabienne Lammers
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Donatella Canella
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Ian M Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Winship Herr
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nouria Hernandez
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Mauro Delorenzi
- Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland; Department of Oncology and the Ludwig Center for Cancer Research, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland
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42
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Liu J, Zhang W, Du G, Chen J, Zhou J. Overproduction of geraniol by enhanced precursor supply in Saccharomyces cerevisiae. J Biotechnol 2013; 168:446-51. [DOI: 10.1016/j.jbiotec.2013.10.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 10/11/2013] [Accepted: 10/16/2013] [Indexed: 10/26/2022]
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43
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Good PD, Kendall A, Ignatz-Hoover J, Miller EL, Pai DA, Rivera SR, Carrick B, Engelke DR. Silencing near tRNA genes is nucleosome-mediated and distinct from boundary element function. Gene 2013; 526:7-15. [PMID: 23707796 PMCID: PMC3745993 DOI: 10.1016/j.gene.2013.05.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 01/22/2023]
Abstract
Transfer RNA (tRNA) genes and other RNA polymerase III transcription units are dispersed in high copy throughout nuclear genomes, and can antagonize RNA polymerase II transcription in their immediate chromosomal locus. Previous work in Saccharomyces cerevisiae found that this local silencing required subnuclear clustering of the tRNA genes near the nucleolus. Here we show that the silencing also requires nucleosome participation, though the nature of the nucleosome interaction appears distinct from other forms of transcriptional silencing. Analysis of an extensive library of histone amino acid substitutions finds a large number of residues that affect the silencing, both in the histone N-terminal tails and on the nucleosome disk surface. The residues on the disk surfaces involved are largely distinct from those affecting other regulatory phenomena. Consistent with the large number of histone residues affecting tgm silencing, survey of chromatin modification mutations shows that several enzymes known to affect nucleosome modification and positioning are also required. The enzymes include an Rpd3 deacetylase complex, Hos1 deacetylase, Glc7 phosphatase, and the RSC nucleosome remodeling activity, but not multiple other activities required for other silencing forms or boundary element function at tRNA gene loci. Models for communication between the tRNA gene transcription complexes and local chromatin are discussed.
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Affiliation(s)
- Paul D. Good
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
| | - Ann Kendall
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
| | | | - Erin L. Miller
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
| | - Dave A. Pai
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
| | - Sara R. Rivera
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
| | - Brian Carrick
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
| | - David R. Engelke
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109-0600, USA
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44
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Mod5 protein binds to tRNA gene complexes and affects local transcriptional silencing. Proc Natl Acad Sci U S A 2013; 110:E3081-9. [PMID: 23898186 DOI: 10.1073/pnas.1219946110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The tRNA gene-mediated (tgm) silencing of RNA polymerase II promoters is dependent on subnuclear clustering of the tRNA genes, but genetic analysis shows that the silencing requires additional mechanisms. We have identified proteins that bind tRNA gene transcription complexes and are required for tgm silencing but not required for gene clustering. One of the proteins, Mod5, is a tRNA modifying enzyme that adds an N6-isopentenyl adenosine modification at position 37 on a small number of tRNAs in the cytoplasm, although a subpopulation of Mod5 is also found in the nucleus. Recent publications have also shown that Mod5 has tumor suppressor characteristics in humans as well as confers drug resistance through prion-like misfolding in yeast. Here, we show that a subpopulation of Mod5 associates with tRNA gene complexes in the nucleolus. This association occurs and is required for tgm silencing regardless of whether the pre-tRNA transcripts are substrates for Mod5 modification. In addition, Mod5 is bound to nuclear pre-tRNA transcripts, although they are not substrates for the A37 modification. Lastly, we show that truncation of the tRNA transcript to remove the normal tRNA structure also alleviates silencing, suggesting that synthesis of intact pre-tRNAs is required for the silencing mechanism. These results are discussed in light of recent results showing that silencing near tRNA genes also requires chromatin modification.
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45
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Rohira AD, Chen CY, Allen JR, Johnson DL. Covalent small ubiquitin-like modifier (SUMO) modification of Maf1 protein controls RNA polymerase III-dependent transcription repression. J Biol Chem 2013; 288:19288-95. [PMID: 23673667 DOI: 10.1074/jbc.m113.473744] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNA polymerase (pol) III transcribes genes that determine biosynthetic capacity. Induction of these genes is required for oncogenic transformation. The transcriptional repressor, Maf1, plays a central role in the repression of these and other genes that promote oncogenesis. Our studies identify an important new role for SUMOylation in repressing RNA pol III-dependent transcription. We show that a key mechanism by which this occurs is through small ubiquitin-like modifier (SUMO) modification of Maf1 by both SUMO1 and SUMO2. Mutation of each lysine residue revealed that Lys-35 is the major SUMOylation site on Maf1 and that the deSUMOylase, SENP1, is responsible for controlling Maf1K35 SUMOylation. SUMOylation of Maf1 is unaffected by rapamycin inhibition of mammalian target of rapamycin (mTOR) and mTOR-dependent Maf1 phosphorylation. By preventing SUMOylation at Lys-35, Maf1 is impaired in its ability to both repress transcription and suppress colony growth. Although SUMOylation does not alter Maf1 subcellular localization, Maf1K35R is defective in its ability to associate with RNA pol III. This impairs Maf1 recruitment to tRNA gene promoters and its ability to facilitate the dissociation of RNA pol III from these promoters. These studies identify a novel role for SUMOylation in controlling Maf1 and RNA pol III-mediated transcription. Given the emerging roles of SENP1, Maf1, and RNA pol III transcription in oncogenesis, our studies support the idea that deSUMOylation of Maf1 and induction of its gene targets play a critical role in cancer development.
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Affiliation(s)
- Aarti D Rohira
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California and the Norris Comprehensive Cancer Center, Los Angeles, California 90033, USA
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46
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Maf1, a general negative regulator of RNA polymerase III in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012. [PMID: 23201230 DOI: 10.1016/j.bbagrm.2012.11.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
tRNA synthesis by yeast RNA polymerase III (Pol III) is down-regulated under growth-limiting conditions. This control is mediated by Maf1, a global negative regulator of Pol III transcription. Conserved from yeast to man, Maf1 was originally discovered in Saccharomyces cerevisiae by a genetic approach. Details regarding the molecular basis of Pol III repression by Maf1 are now emerging from the recently reported structural and biochemical data on Pol III and Maf1. The phosphorylation status of Maf1 determines its nuclear localization and interaction with the Pol III complex and several Maf1 kinases have been identified to be involved in Pol III control. Moreover, Maf1 indirectly affects tRNA maturation and decay. Here I discuss the current understanding of the mechanisms that oversee the Maf1-mediated regulation of Pol III activity and the role of Maf1 in the control of tRNA biosynthesis in yeast. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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47
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Moir RD, Willis IM. Regulation of pol III transcription by nutrient and stress signaling pathways. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:361-75. [PMID: 23165150 DOI: 10.1016/j.bbagrm.2012.11.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 11/06/2012] [Accepted: 11/08/2012] [Indexed: 12/29/2022]
Abstract
Transcription by RNA polymerase III (pol III) is responsible for ~15% of total cellular transcription through the generation of small structured RNAs such as tRNA and 5S RNA. The coordinate synthesis of these molecules with ribosomal protein mRNAs and rRNA couples the production of ribosomes and their tRNA substrates and balances protein synthetic capacity with the growth requirements of the cell. Ribosome biogenesis in general and pol III transcription in particular is known to be regulated by nutrient availability, cell stress and cell cycle stage and is perturbed in pathological states. High throughput proteomic studies have catalogued modifications to pol III subunits, assembly, initiation and accessory factors but most of these modifications have yet to be linked to functional consequences. Here we review our current understanding of the major points of regulation in the pol III transcription apparatus, the targets of regulation and the signaling pathways known to regulate their function. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- Robyn D Moir
- Departments of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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48
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Dieci G, Bosio MC, Fermi B, Ferrari R. Transcription reinitiation by RNA polymerase III. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:331-41. [PMID: 23128323 DOI: 10.1016/j.bbagrm.2012.10.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/19/2012] [Accepted: 10/23/2012] [Indexed: 01/11/2023]
Abstract
The retention of transcription proteins at an actively transcribed gene contributes to maintenance of the active transcriptional state and increases the rate of subsequent transcription cycles relative to the initial cycle. This process, called transcription reinitiation, generates the abundant RNAs in living cells. The persistence of stable preinitiation intermediates on activated genes representing at least a subset of basal transcription components has long been recognized as a shared feature of RNA polymerase (Pol) I, II and III-dependent transcription in eukaryotes. Studies of the Pol III transcription machinery and its target genes in eukaryotic genomes over the last fifteen years, has uncovered multiple details on transcription reinitiation. In addition to the basal transcription factors that recruit the polymerase, Pol III itself can be retained on the same gene through multiple transcription cycles by a facilitated recycling pathway. The molecular bases for facilitated recycling are progressively being revealed with advances in structural and functional studies. At the same time, progress in our understanding of Pol III transcriptional regulation in response to different environmental cues points to the specific mechanism of Pol III reinitiation as a key target of signaling pathway regulation of cell growth. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- Giorgio Dieci
- Dipartimento di Bioscienze, Università degli Studi di Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
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Acker J, Conesa C, Lefebvre O. Yeast RNA polymerase III transcription factors and effectors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:283-95. [PMID: 23063749 DOI: 10.1016/j.bbagrm.2012.10.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/27/2012] [Accepted: 10/03/2012] [Indexed: 12/19/2022]
Abstract
Recent data indicate that the well-defined transcription machinery of RNA polymerase III (Pol III) is probably more complex than commonly thought. In this review, we describe the yeast basal transcription factors of Pol III and their involvements in the transcription cycle. We also present a list of proteins detected on genes transcribed by Pol III (class III genes) that might participate in the transcription process. Surprisingly, several of these proteins are involved in RNA polymerase II transcription. Defining the role of these potential new effectors in Pol III transcription in vivo will be the challenge of the next few years. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- Joël Acker
- CEA, iBiTecS, Gif Sur Yvette, F-91191, France
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50
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Turowski TW, Karkusiewicz I, Kowal J, Boguta M. Maf1-mediated repression of RNA polymerase III transcription inhibits tRNA degradation via RTD pathway. RNA (NEW YORK, N.Y.) 2012; 18:1823-32. [PMID: 22919049 PMCID: PMC3446706 DOI: 10.1261/rna.033597.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
tRNA precursors, which are transcribed by RNA polymerase III, undergo end-maturation, splicing, and base modifications. Hypomodified tRNAs, such as tRNA(Val(AAC)), lacking 7-methylguanosine and 5-methylcytidine modifications, are subject to degradation by a rapid tRNA decay pathway. Here we searched for genes which, when overexpressed, restored stability of tRNA(Val(AAC)) molecules in a modification-deficient trm4Δtrm8Δ mutant. We identified TEF1 and VAS1, encoding elongation factor eEF1A and valyl-tRNA synthetase respectively, which likely protect hypomodified tRNA(Val(AAC)) by direct interactions. We also identified MAF1 whose product is a general negative regulator of RNA polymerase III. Expression of a Maf1-7A mutant that constitutively repressed RNA polymerase III transcription resulted in increased stability of hypomodified tRNA(Val(AAC)). Strikingly, inhibition of tRNA transcription in a Maf1-independent manner, either by point mutation in RNA polymerase III subunit Rpc128 or decreased expression of Rpc17 subunit, also suppressed the turnover of the hypomodified tRNA(Val(AAC)). These results support a model where inhibition of tRNA transcription leads to stabilization of hypomodified tRNA(Val(AAC)) due to more efficient protection by tRNA-interacting proteins.
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Affiliation(s)
- Tomasz W. Turowski
- Institute of Biotechnology, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
| | - Iwona Karkusiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Justyna Kowal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Magdalena Boguta
- Institute of Biotechnology, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Corresponding authorE-mail
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