1
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Pinzaru AM, Tavazoie SF. Transfer RNAs as dynamic and critical regulators of cancer progression. Nat Rev Cancer 2023; 23:746-761. [PMID: 37814109 DOI: 10.1038/s41568-023-00611-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/28/2023] [Indexed: 10/11/2023]
Abstract
Transfer RNAs (tRNAs) have been historically viewed as non-dynamic adaptors that decode the genetic code into proteins. Recent work has uncovered dynamic regulatory roles for these fascinating molecules. Advances in tRNA detection methods have revealed that specific tRNAs can become modulated upon DNA copy number and chromatin alterations and can also be perturbed by oncogenic signalling and transcriptional regulators in cancer cells or the tumour microenvironment. Such alterations in the levels of specific tRNAs have been shown to causally impact cancer progression, including metastasis. Moreover, sequencing methods have identified tRNA-derived small RNAs that influence various aspects of cancer progression, such as cell proliferation and invasion, and could serve as diagnostic and prognostic biomarkers or putative therapeutic targets in various cancers. Finally, there is accumulating evidence, including from genetic models, that specific tRNA synthetases - the enzymes responsible for charging tRNAs with amino acids - can either promote or suppress tumour formation. In this Review, we provide an overview of how deregulation of tRNAs influences cancer formation and progression.
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Affiliation(s)
- Alexandra M Pinzaru
- Laboratory of Systems Cancer Biology, The Rockefeller University, New York, NY, USA.
| | - Sohail F Tavazoie
- Laboratory of Systems Cancer Biology, The Rockefeller University, New York, NY, USA.
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2
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Li Y, Gao J, Wang Y, Cai J, Wu D, Wang L, Pu W, Yu F, Zhu S. The functions of a 5' tRNA-Ala-derived fragment in gene expression. PLANT PHYSIOLOGY 2023; 193:1126-1141. [PMID: 37350495 DOI: 10.1093/plphys/kiad361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/04/2023] [Accepted: 05/22/2023] [Indexed: 06/24/2023]
Abstract
Transfer RNA (tRNA) can produce smaller RNA fragments called tRNA-derived fragments (tRFs). tRFs play critical roles in multiple cellular programs, although the functional mechanisms of tRFs remain largely unknown in plants. In this study, we examined the phenotype associated with 5' tRF-Ala (tRF-Ala, produced from tRNA-Ala) overexpression and knockdown lines (tDR-Ala-OE and tDR-Ala-kd, respectively) and the mechanisms by which tRF-Ala affects mRNA levels in Arabidopsis (Arabidopsis thaliana). We investigated the candidate proteins associated with tRF-Ala by quantitative proteomics and confirmed the direct interaction between tRF-Ala and the splicing factor SERINE-ARGININE RICH PROTEIN 34 (SR34). A transcriptome sequencing analysis showed that 318 genes among all the genes (786) with substantial alternative splicing (AS) variance in tDR-Ala-OE lines are targets of SR34. tRF-Ala diminished the binding affinity between SR34 and its targets by direct competition for interaction with SR34. These findings reveal the critical roles of tRF-Ala in regulating mRNA levels and splicing.
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Affiliation(s)
- Yuanyuan Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
| | - Junping Gao
- Technology Center, China Tobacco Hunan Industrial Co., Ltd., Changsha 410007, China
| | - Ying Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
| | - Jun Cai
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
| | - Dousheng Wu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
| | - Long Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
| | - Wenxuan Pu
- Technology Center, China Tobacco Hunan Industrial Co., Ltd., Changsha 410007, China
| | - Feng Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
| | - Sirui Zhu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, China
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3
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Bir J, Rojo-Bartolomé I, Lekube X, Diaz de Cerio O, Ortiz-Zarragoitia M, Cancio I. High production of transfer RNAs identifies the presence of developing oocytes in ovaries and intersex testes of teleost fish. MARINE ENVIRONMENTAL RESEARCH 2023; 186:105907. [PMID: 36774708 DOI: 10.1016/j.marenvres.2023.105907] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/03/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
5S rRNA is highly transcribed in fish oocytes and this transcription levels can be used to identify the presence of oocytes in the intersex testes of fish exposed to xenoestrogens. Similar to 5S rRNA, tRNAs are transcribed by RNA polymerase III (Pol-III) in eukaryotes, so this study focuses in the analysis of the levels of expression of tRNAs in the gonads (ovaries and testes) of eight teleost species as a possible new oocyte molecular marker. Total RNA extracted from gonads of six commercial teleost species in the Biscay Bay, from the pollution sentinel species thicklip grey mullet (Chelon labrosus) known present intersex testes in response to xenoestrogens in Gernika estuary and from the laboratory model species Danio rerio were analysed through capillary electrophoresis. Bioanalyzer electropherograms were used to quantify the concentrations of tRNAs, 5S and 5.8S rRNA. All studied ovaries expressed significantly higher levels of tRNAs and 5S rRNA than testes. A tRNA to 5.8S rRNA index was calculated which differentiates ovaries from testes, and identifies some intersex testes in between testes and ovaries in mullets. The tRNA/5.8S ratio was highest in ovaries in previtellogenic stage, decreasing towards maturity. Thus, strong oocyte expression of tRNAs is an additional proof of high activity levels of Pol-III during early stages of oocyte development in teleost ovaries. Incidentally, we observed that miRNA concentrations were always higher in testes than ovaries. The indexing approach developed in the present study could have multiple applications in teleost reproduction research and in the development of early molecular markers of intersex condition.
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Affiliation(s)
- Joyanta Bir
- CBET Research Group, Dept. of Zoology and Animal Cell Biology, Fac. Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology (PiE-UPV/EHU), University of the Basque Country (UPV/EHU), Areatza 47, 48620, Plentzia, Basque Country, Spain; Fisheries and Marine Resources Technology Discipline, School of Life Sciences, Khulna University, Khulna, 9208, Bangladesh
| | - Iratxe Rojo-Bartolomé
- CBET Research Group, Dept. of Zoology and Animal Cell Biology, Fac. Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology (PiE-UPV/EHU), University of the Basque Country (UPV/EHU), Areatza 47, 48620, Plentzia, Basque Country, Spain
| | - Xabier Lekube
- Biscay Bay Environmental Biospecimen Bank (BBEBB), Research Centre for Experimental Marine Biology and Biotechnology (PiE-UPV/EHU), University of the Basque Country (UPV/EHU), Areatza 47, 48620, Plentzia, Basque Country, Spain
| | - Oihane Diaz de Cerio
- CBET Research Group, Dept. of Zoology and Animal Cell Biology, Fac. Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology (PiE-UPV/EHU), University of the Basque Country (UPV/EHU), Areatza 47, 48620, Plentzia, Basque Country, Spain
| | - Maren Ortiz-Zarragoitia
- CBET Research Group, Dept. of Zoology and Animal Cell Biology, Fac. Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology (PiE-UPV/EHU), University of the Basque Country (UPV/EHU), Areatza 47, 48620, Plentzia, Basque Country, Spain
| | - Ibon Cancio
- CBET Research Group, Dept. of Zoology and Animal Cell Biology, Fac. Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology (PiE-UPV/EHU), University of the Basque Country (UPV/EHU), Areatza 47, 48620, Plentzia, Basque Country, Spain.
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4
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Sizer RE, Chahid N, Butterfield SP, Donze D, Bryant NJ, White RJ. TFIIIC-based chromatin insulators through eukaryotic evolution. Gene X 2022; 835:146533. [PMID: 35623477 DOI: 10.1016/j.gene.2022.146533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 04/19/2022] [Accepted: 04/29/2022] [Indexed: 11/04/2022] Open
Abstract
Eukaryotic chromosomes are divided into domains with distinct structural and functional properties, such as differing levels of chromatin compaction and gene transcription. Domains of relatively compact chromatin and minimal transcription are termed heterochromatic, whereas euchromatin is more open and actively transcribed. Insulators separate these domains and maintain their distinct features. Disruption of insulators can cause diseases such as cancer. Many insulators contain tRNA genes (tDNAs), examples of which have been shown to block the spread of activating or silencing activities. This characteristic of specific tDNAs is conserved through evolution, such that human tDNAs can serve as barriers to the spread of silencing in fission yeast. Here we demonstrate that tDNAs from the methylotrophic fungus Pichia pastoris can function effectively as insulators in distantly-related budding yeast. Key to the function of tDNAs as insulators is TFIIIC, a transcription factor that is also required for their expression. TFIIIC binds additional loci besides tDNAs, some of which have insulator activity. Although the mechanistic basis of TFIIIC-based insulation has been studied extensively in yeast, it is largely uncharacterized in metazoa. Utilising publicly-available genome-wide ChIP-seq data, we consider the extent to which mechanisms conserved from yeast to man may suffice to allow efficient insulation by TFIIIC in the more challenging chromatin environments of metazoa and suggest features that may have been acquired during evolution to cope with new challenges. We demonstrate the widespread presence at human tDNAs of USF1, a transcription factor with well-established barrier activity in vertebrates. We predict that tDNA-based insulators in higher organisms have evolved through incorporation of modules, such as binding sites for factors like USF1 and CTCF that are absent from yeasts, thereby strengthening function and providing opportunities for regulation between cell types.
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Affiliation(s)
- Rebecca E Sizer
- Department of Biology, The University of York, York YO10 5DD, UK
| | - Nisreen Chahid
- Department of Biology, The University of York, York YO10 5DD, UK
| | | | - David Donze
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Nia J Bryant
- Department of Biology, The University of York, York YO10 5DD, UK
| | - Robert J White
- Department of Biology, The University of York, York YO10 5DD, UK.
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5
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Wang Q, Daiß JL, Xu Y, Engel C. Snapshots of RNA polymerase III in action - A mini review. Gene 2022; 821:146282. [PMID: 35149153 DOI: 10.1016/j.gene.2022.146282] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/20/2022] [Accepted: 02/03/2022] [Indexed: 11/04/2022]
Abstract
RNA polymerase (Pol) III is responsible for the transcription of tRNAs, 5S rRNA, U6 snRNA, and other non-coding RNAs. Transcription factors such as TFIIIA, -B, -C, SNAPc, and Maf1 are required for promoter recognition, promoter opening, and Pol III activity regulation. Recent developments in cryo-electron microscopy and advanced purification approaches for endogenous multi-subunit complexes accelerated structural studies resulting in detailed structural insights which allowed an in-depth understanding of the molecular mechanisms underlying Pol III transcription. Here, we summarize structural data on Pol III and its regulating factors providing a three-dimensional framework to guide further analysis of RNA polymerase III.
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Affiliation(s)
- Qianmin Wang
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Institute of Precision Medicine, Shanghai, China; Present address: Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, 93053, Regensburg, Germany
| | - Youwei Xu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, 93053, Regensburg, Germany.
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6
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Malcolm JR, Leese NK, Lamond-Warner PI, Brackenbury WJ, White RJ. Widespread association of ERα with RMRP and tRNA genes in MCF-7 cells and breast cancers. Gene X 2022; 821:146280. [PMID: 35143945 PMCID: PMC8942118 DOI: 10.1016/j.gene.2022.146280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/21/2022] [Accepted: 02/03/2022] [Indexed: 12/04/2022] Open
Abstract
Estrogen receptor (ER) interacts with hundreds of tRNA genes (tDNAs) in MCF-7 cells. Hundreds of tDNAs are also targeted in primary breast tumours and metastases. Canonical estrogen response element is not found near top tDNA targets of ER. ER also targets non-coding breast cancer driver gene RMRP. ER also targets RN7SL1 gene that promotes breast cancer progression.
tRNA gene transcription by RNA polymerase III (Pol III) is a tightly regulated process, but dysregulated Pol III transcription is widely observed in cancers. Approximately 75% of all breast cancers are positive for expression of Estrogen Receptor alpha (ERα), which acts as a key driver of disease. MCF-7 cells rapidly upregulate tRNA gene transcription in response to estrogen and ChIP-PCR demonstrated ERα enrichment at tRNALeu and 5S rRNA genes in this breast cancer cell line. While these data implicate the ERα as a Pol III transcriptional regulator, how widespread this regulation is across the 631 tRNA genes has yet to be revealed. Through analyses of ERα ChIP-seq datasets, we show that ERα interacts with hundreds of tRNA genes, not only in MCF-7 cells, but also in primary human breast tumours and distant metastases. The extent of ERα association with tRNA genes varies between breast cancer cell lines and does not correlate with levels of ERα binding to its canonical target gene GREB1. Amongst other Pol III-transcribed genes, ERα is consistently enriched at the long non-coding RNA gene RMRP, a positive regulator of cell cycle progression that is subject to focal amplification in tumours. Another Pol III template targeted by ERα is the RN7SL1 gene, which is strongly implicated in breast cancer pathology by inducing inflammatory responses in tumours. Our data indicate that Pol III-transcribed non-coding genes should be added to the list of ERα targets in breast cancer.
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Affiliation(s)
- Jodie R Malcolm
- Department of Biology, The University of York, Heslington Road, YO10 5DD, United Kingdom
| | - Natasha K Leese
- Department of Biology, The University of York, Heslington Road, YO10 5DD, United Kingdom
| | | | - William J Brackenbury
- Department of Biology, The University of York, Heslington Road, YO10 5DD, United Kingdom
| | - Robert J White
- Department of Biology, The University of York, Heslington Road, YO10 5DD, United Kingdom.
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7
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Chen L, Xu W, Liu K, Jiang Z, Han Y, Jin H, Zhang L, Shen W, Jia S, Sun Q, Meng A. 5' Half of specific tRNAs feeds back to promote corresponding tRNA gene transcription in vertebrate embryos. SCIENCE ADVANCES 2021; 7:eabh0494. [PMID: 34797706 PMCID: PMC8604414 DOI: 10.1126/sciadv.abh0494] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
5′tRFls are small transfer RNA (tRNA) fragments derived from 5′ half of mature tRNAs. However, it is unknown whether 5′tRFls could feed back to regulate tRNA biogenesis. Here, we show that 5′tRFlGly/GCC and 5′tRFlGlu/CTC function to promote transcription of corresponding tRNA genes and are essential for vertebrate early embryogenesis. During zebrafish embryogenesis, dynamics of 5′tRFlGly/GCC and 5′tRFlGlu/CTC levels correlates with that of tRNAGly/GCC and tRNAGlu/CTC levels. Morpholino-mediated knockdown of 5′tRFlGly/GCC or 5′tRFlGlu/CTC down-regulates tRNAGly/GCC or tRNAGlu/CTC levels, respectively, and causes embryonic lethality that is efficiently rescued by coinjection of properly refolded corresponding tRNA. In zebrafish embryos, tRNA:DNA and 5′tRFl:DNA hybrids commonly exist on the template strand of tRNA genes. Mechanistically, unstable 5′tRFl:DNA hybrid may prevent the formation of transcriptionally inhibitory stable tRNA:DNA hybrids on the same tRNA loci so as to facilitate tRNA gene transcription. The uncovered mechanism may be implicated in other physiological and pathological processes.
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Affiliation(s)
- Luxi Chen
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xu
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
- The Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kunpeng Liu
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
- The Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zheng Jiang
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yang Han
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongbin Jin
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lin Zhang
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Weimin Shen
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shunji Jia
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qianwen Sun
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
- The Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Anming Meng
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Guangzhou Laboratory, Guangzhou 510320, Guangdong Province, China
- Corresponding author.
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8
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Turowski TW, Boguta M. Specific Features of RNA Polymerases I and III: Structure and Assembly. Front Mol Biosci 2021; 8:680090. [PMID: 34055890 PMCID: PMC8160253 DOI: 10.3389/fmolb.2021.680090] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 04/16/2021] [Indexed: 12/22/2022] Open
Abstract
RNA polymerase I (RNAPI) and RNAPIII are multi-heterogenic protein complexes that specialize in the transcription of highly abundant non-coding RNAs, such as ribosomal RNA (rRNA) and transfer RNA (tRNA). In terms of subunit number and structure, RNAPI and RNAPIII are more complex than RNAPII that synthesizes thousands of different mRNAs. Specific subunits of the yeast RNAPI and RNAPIII form associated subcomplexes that are related to parts of the RNAPII initiation factors. Prior to their delivery to the nucleus where they function, RNAP complexes are assembled at least partially in the cytoplasm. Yeast RNAPI and RNAPIII share heterodimer Rpc40-Rpc19, a functional equivalent to the αα homodimer which initiates assembly of prokaryotic RNAP. In the process of yeast RNAPI and RNAPIII biogenesis, Rpc40 and Rpc19 form the assembly platform together with two small, bona fide eukaryotic subunits, Rpb10 and Rpb12. We propose that this assembly platform is co-translationally seeded while the Rpb10 subunit is synthesized by cytoplasmic ribosome machinery. The translation of Rpb10 is stimulated by Rbs1 protein, which binds to the 3′-untranslated region of RPB10 mRNA and hypothetically brings together Rpc19 and Rpc40 subunits to form the αα-like heterodimer. We suggest that such a co-translational mechanism is involved in the assembly of RNAPI and RNAPIII complexes.
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Affiliation(s)
- Tomasz W Turowski
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Magdalena Boguta
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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9
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Zorn P, Misiak D, Gekle M, Köhn M. Identification and initial characterization of POLIII-driven transcripts by msRNA-sequencing. RNA Biol 2021; 18:1807-1817. [PMID: 33404286 PMCID: PMC8583065 DOI: 10.1080/15476286.2020.1871216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Non-coding RNAs (ncRNAs) are powerful regulators of gene expression but medium-sized (50–300 nts in length) ncRNAs (msRNAs) are barely picked-up precisely by RNA-sequencing. Here we describe msRNA-sequencing (msRNAseq), a modified protocol that associated with a computational analyses pipeline identified about ~1800 msRNA loci, including over 300 putatively novel msRNAs, in human and murine cells. We focused on the identification and initial characterization of three POLIII-derived transcripts. The validation of these uncharacterized msRNAs identified an ncRNA in antisense orientation from the POLR3E locus transcribed by POLIII. This msRNA, termed POLAR (POLR3E Antisense RNA), has a strikingly short half-life, localizes to paraspeckles (PSPs) and associates with PSP-associated proteins indicating that msRNAseq identifies functional msRNAs. Thus, our analyses will pave the way for analysing the roles of msRNAs in cells, development and diseases.
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Affiliation(s)
| | - Danny Misiak
- Institute of Molecular Medicine, University of Halle-Wittenberg, Halle (Saale), Germany
| | - Michael Gekle
- Julius-Bernstein-Institute of Physiology, University of Halle-Wittenberg, Germany
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10
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Moir RD, Lavados C, Lee J, Willis IM. Functional characterization of Polr3a hypomyelinating leukodystrophy mutations in the S. cerevisiae homolog, RPC160. Gene 2020; 768:145259. [PMID: 33148458 DOI: 10.1016/j.gene.2020.145259] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/23/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022]
Abstract
Mutations in RNA polymerase III (Pol III) cause hypomeylinating leukodystrophy (HLD) and neurodegeneration in humans. POLR3A and POLR3B, the two largest Pol III subunits, together form the catalytic center and carry the majority of disease alleles. Disease-causing mutations include invariant and highly conserved residues that are predicted to negatively affect Pol III activity and decrease transcriptional output. A subset of HLD missense mutations in POLR3A cluster in the pore region that provides nucleotide access to the Pol III active site. These mutations were engineered at the corresponding positions in the Saccharomyces cerevisiae homolog, Rpc160, to evaluate their functional deficits. None of the mutations caused a growth or transcription phenotype in yeast. Each mutation was combined with a frequently occurring pore mutation, POLR3A G672E, which was also wild-type for growth and transcription. The double mutants showed a spectrum of phenotypes from wild-type to lethal, with only the least fit combinations showing an effect on Pol III transcription. In one slow-growing temperature-sensitive mutant the steady-state level of tRNAs was unaffected, however global tRNA synthesis was compromised, as was the synthesis of RPR1 and SNR52 RNAs. Affinity-purified mutant Pol III was broadly defective in both factor-independent and factor-dependent transcription in vitro across genes that represent the yeast Pol III transcriptome. Thus, the robustness of yeast Rpc160 to single Pol III leukodystrophy mutations in the pore domain can be overcome by a second mutation in the domain.
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Affiliation(s)
- Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Christian Lavados
- Graduate Program in Biomedical Science, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - JaeHoon Lee
- Department of Medicine (Cardiology), Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ian M Willis
- Departments of Biochemistry and Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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11
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Structure of the TFIIIC subcomplex τA provides insights into RNA polymerase III pre-initiation complex formation. Nat Commun 2020; 11:4905. [PMID: 32999288 PMCID: PMC7528018 DOI: 10.1038/s41467-020-18707-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 09/08/2020] [Indexed: 01/05/2023] Open
Abstract
Transcription factor (TF) IIIC is a conserved eukaryotic six-subunit protein complex with dual function. It serves as a general TF for most RNA polymerase (Pol) III genes by recruiting TFIIIB, but it is also involved in chromatin organization and regulation of Pol II genes through interaction with CTCF and condensin II. Here, we report the structure of the S. cerevisiae TFIIIC subcomplex τA, which contains the most conserved subunits of TFIIIC and is responsible for recruitment of TFIIIB and transcription start site (TSS) selection at Pol III genes. We show that τA binding to its promoter is auto-inhibited by a disordered acidic tail of subunit τ95. We further provide a negative-stain reconstruction of τA bound to the TFIIIB subunits Brf1 and TBP. This shows that a ruler element in τA achieves positioning of TFIIIB upstream of the TSS, and suggests remodeling of the complex during assembly of TFIIIB by TFIIIC.
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12
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Transcription-independent TFIIIC-bound sites cluster near heterochromatin boundaries within lamina-associated domains in C. elegans. Epigenetics Chromatin 2020; 13:1. [PMID: 31918747 PMCID: PMC6950938 DOI: 10.1186/s13072-019-0325-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/20/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chromatin organization is central to precise control of gene expression. In various eukaryotic species, domains of pervasive cis-chromatin interactions demarcate functional domains of the genomes. In nematode Caenorhabditis elegans, however, pervasive chromatin contact domains are limited to the dosage-compensated sex chromosome, leaving the principle of C. elegans chromatin organization unclear. Transcription factor III C (TFIIIC) is a basal transcription factor complex for RNA polymerase III, and is implicated in chromatin organization. TFIIIC binding without RNA polymerase III co-occupancy, referred to as extra-TFIIIC binding, has been implicated in insulating active and inactive chromatin domains in yeasts, flies, and mammalian cells. Whether extra-TFIIIC sites are present and contribute to chromatin organization in C. elegans remains unknown. RESULTS We identified 504 TFIIIC-bound sites absent of RNA polymerase III and TATA-binding protein co-occupancy characteristic of extra-TFIIIC sites in C. elegans embryos. Extra-TFIIIC sites constituted half of all identified TFIIIC binding sites in the genome. Extra-TFIIIC sites formed dense clusters in cis. The clusters of extra-TFIIIC sites were highly over-represented within the distal arm domains of the autosomes that presented a high level of heterochromatin-associated histone H3K9 trimethylation (H3K9me3). Furthermore, extra-TFIIIC clusters were embedded in the lamina-associated domains. Despite the heterochromatin environment of extra-TFIIIC sites, the individual clusters of extra-TFIIIC sites were devoid of and resided near the individual H3K9me3-marked regions. CONCLUSION Clusters of extra-TFIIIC sites were pervasive in the arm domains of C. elegans autosomes, near the outer boundaries of H3K9me3-marked regions. Given the reported activity of extra-TFIIIC sites in heterochromatin insulation in yeasts, our observation raised the possibility that TFIIIC may also demarcate heterochromatin in C. elegans.
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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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Choquet K, Forget D, Meloche E, Dicaire MJ, Bernard G, Vanderver A, Schiffmann R, Fabian MR, Teichmann M, Coulombe B, Brais B, Kleinman CL. Leukodystrophy-associated POLR3A mutations down-regulate the RNA polymerase III transcript and important regulatory RNA BC200. J Biol Chem 2019; 294:7445-7459. [PMID: 30898877 PMCID: PMC6509492 DOI: 10.1074/jbc.ra118.006271] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 03/07/2019] [Indexed: 12/12/2022] Open
Abstract
RNA polymerase III (Pol III) is an essential enzyme responsible for the synthesis of several small noncoding RNAs, a number of which are involved in mRNA translation. Recessive mutations in POLR3A, encoding the largest subunit of Pol III, cause POLR3-related hypomyelinating leukodystrophy (POLR3–HLD), characterized by deficient central nervous system myelination. Identification of the downstream effectors of pathogenic POLR3A mutations has so far been elusive. Here, we used CRISPR-Cas9 to introduce the POLR3A mutation c.2554A→G (p.M852V) into human cell lines and assessed its impact on Pol III biogenesis, nuclear import, DNA occupancy, transcription, and protein levels. Transcriptomic profiling uncovered a subset of transcripts vulnerable to Pol III hypofunction, including a global reduction in tRNA levels. The brain cytoplasmic BC200 RNA (BCYRN1), involved in translation regulation, was consistently affected in all our cellular models, including patient-derived fibroblasts. Genomic BC200 deletion in an oligodendroglial cell line led to major transcriptomic and proteomic changes, having a larger impact than those of POLR3A mutations. Upon differentiation, mRNA levels of the MBP gene, encoding myelin basic protein, were significantly decreased in POLR3A-mutant cells. Our findings provide the first evidence for impaired Pol III transcription in cellular models of POLR3–HLD and identify several candidate effectors, including BC200 RNA, having a potential role in oligodendrocyte biology and involvement in the disease.
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Affiliation(s)
- Karine Choquet
- From the Department of Human Genetics, McGill University, Montréal, Québec H3A 0C7, Canada.,the Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec H3T 1E2, Canada.,the Montréal Neurological Institute, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Diane Forget
- the Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec H2W 1R7, Canada
| | - Elisabeth Meloche
- the Montréal Neurological Institute, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Marie-Josée Dicaire
- the Montréal Neurological Institute, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Geneviève Bernard
- From the Department of Human Genetics, McGill University, Montréal, Québec H3A 0C7, Canada.,Pediatrics, McGill University, Montréal, Québec H3A 0G4, Canada.,the Department of Internal Medicine, Division of Medical Genetics, Montréal Children's Hospital, McGill University Health Center, Montréal, Québec H4A 3J1, Canada.,the Child Health and Human Development Program, and.,MyeliNeuroGene Laboratory, Research Institute, McGill University Health Center, Montréal, Québec H4A 3J1, Canada.,the Departments of Neurology and Neurosurgery and
| | - Adeline Vanderver
- the Division of Neurology, Children's Hospital of Philadelphia (CHOP), Philadelphia, Pennsylvania 19104
| | - Raphael Schiffmann
- the Institute of Metabolic Disease, Baylor Research Institute, Dallas, Texas 75204
| | - Marc R Fabian
- the Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
| | - Martin Teichmann
- INSERM U1212-CNRS UMR5320, Université de Bordeaux, Bordeaux, France, and
| | - Benoit Coulombe
- the Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec H2W 1R7, Canada.,the Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Bernard Brais
- From the Department of Human Genetics, McGill University, Montréal, Québec H3A 0C7, Canada.,the Montréal Neurological Institute, McGill University, Montréal, Québec H3A 2B4, Canada.,the Departments of Neurology and Neurosurgery and
| | - Claudia L Kleinman
- From the Department of Human Genetics, McGill University, Montréal, Québec H3A 0C7, Canada, .,the Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
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Mishra S, Maraia RJ. RNA polymerase III subunits C37/53 modulate rU:dA hybrid 3' end dynamics during transcription termination. Nucleic Acids Res 2019; 47:310-327. [PMID: 30407541 PMCID: PMC6326807 DOI: 10.1093/nar/gky1109] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/22/2018] [Indexed: 12/18/2022] Open
Abstract
RNA polymerase (RNAP) III synthesizes tRNAs and other transcripts, and mutations to its subunits cause human disorders. The RNAP III subunit-heterodimer C37/53 functions in initiation, elongation and in termination-associated reinitiation with subunit C11. C37/53 is related to heterodimers associated with RNAPs I and II, and C11 is related to TFIIS and Rpa12.2, the active site RNA 3' cleavage factors for RNAPs II and I. Critical to termination is stability of the RNA:DNA hybrid bound in the active center, which is loose for RNAP III relative to other RNAPs. Here, we examined RNAP III lacking C37/53/C11 and various reconstituted forms during termination. First, we established a minimal terminator as 5T and 3A on the non-template and template DNA strands, respectively. We demonstrate that C11 stimulates termination, and does so independently of its RNA cleavage activity. We found that C37/53 sensitizes RNAP III termination to RNA:DNA hybrid strength and promotes RNA 3' end pairing/annealing with the template. The latter counteracts C11-insensitive arrest in the proximal part of the oligo(T)-tract, promoting oligo(rU:dA) extension toward greater hybrid instability and RNA release. The data also indicate that RNA 3' end engagement with the active site is a determinant of termination. Broader implications are also discussed.
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Affiliation(s)
- Saurabh Mishra
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard J Maraia
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- Commissioned Corps, U.S. Public Health Service, Rockville, MD 20852, USA
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