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Schwank K, Schmid C, Fremter T, Engel C, Milkereit P, Griesenbeck J, Tschochner H. Features of yeast RNA polymerase I with special consideration of the lobe binding subunits. Biol Chem 2023; 404:979-1002. [PMID: 37823775 DOI: 10.1515/hsz-2023-0184] [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: 04/14/2023] [Accepted: 07/13/2023] [Indexed: 10/13/2023]
Abstract
Ribosomal RNAs (rRNAs) are structural components of ribosomes and represent the most abundant cellular RNA fraction. In the yeast Saccharomyces cerevisiae, they account for more than 60 % of the RNA content in a growing cell. The major amount of rRNA is synthesized by RNA polymerase I (Pol I). This enzyme transcribes exclusively the rRNA gene which is tandemly repeated in about 150 copies on chromosome XII. The high number of transcribed rRNA genes, the efficient recruitment of the transcription machinery and the dense packaging of elongating Pol I molecules on the gene ensure that enough rRNA is generated. Specific features of Pol I and of associated factors confer promoter selectivity and both elongation and termination competence. Many excellent reviews exist about the state of research about function and regulation of Pol I and how Pol I initiation complexes are assembled. In this report we focus on the Pol I specific lobe binding subunits which support efficient, error-free, and correctly terminated rRNA synthesis.
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Affiliation(s)
- Katrin Schwank
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Catharina Schmid
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Tobias Fremter
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Christoph Engel
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Philipp Milkereit
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Joachim Griesenbeck
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Herbert Tschochner
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
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2
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Midha T, Mallory JD, Kolomeisky AB, Igoshin OA. Synergy among Pausing, Intrinsic Proofreading, and Accessory Proteins Results in Optimal Transcription Speed and Tolerable Accuracy. J Phys Chem Lett 2023; 14:3422-3429. [PMID: 37010247 DOI: 10.1021/acs.jpclett.3c00345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Cleavage of dinucleotides after the misincorporational pauses serves as a proofreading mechanism that increases transcriptional elongation accuracy. The accuracy is further improved by accessory proteins such as GreA and TFIIS. However, it is not clear why RNAP pauses and why cleavage-factor-assisted proofreading is necessary despite transcriptional errors in vitro being of the same order as those in downstream translation. Here, we developed a chemical-kinetic model that incorporates most relevant features of transcriptional proofreading and uncovers how the balance between speed and accuracy is achieved. We found that long pauses are essential for high accuracy, whereas cleavage-factor-stimulated proofreading optimizes speed. Moreover, in comparison to the cleavage of a single nucleotide or three nucleotides, RNAP backtracking and dinucleotide cleavage improve both speed and accuracy. Our results thereby show how the molecular mechanism and the kinetic parameters of the transcriptional process were evolutionarily optimized to achieve maximal speed and tolerable accuracy.
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Affiliation(s)
- Tripti Midha
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Joel D Mallory
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Anatoly B Kolomeisky
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Oleg A Igoshin
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
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3
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Chung C, Verheijen BM, Navapanich Z, McGann EG, Shemtov S, Lai GJ, Arora P, Towheed A, Haroon S, Holczbauer A, Chang S, Manojlovic Z, Simpson S, Thomas KW, Kaplan C, van Hasselt P, Timmers M, Erie D, Chen L, Gout JF, Vermulst M. Evolutionary conservation of the fidelity of transcription. Nat Commun 2023; 14:1547. [PMID: 36941254 PMCID: PMC10027832 DOI: 10.1038/s41467-023-36525-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/03/2023] [Indexed: 03/23/2023] Open
Abstract
Accurate transcription is required for the faithful expression of genetic information. However, relatively little is known about the molecular mechanisms that control the fidelity of transcription, or the conservation of these mechanisms across the tree of life. To address these issues, we measured the error rate of transcription in five organisms of increasing complexity and found that the error rate of RNA polymerase II ranges from 2.9 × 10-6 ± 1.9 × 10-7/bp in yeast to 4.0 × 10-6 ± 5.2 × 10-7/bp in worms, 5.69 × 10-6 ± 8.2 × 10-7/bp in flies, 4.9 × 10-6 ± 3.6 × 10-7/bp in mouse cells and 4.7 × 10-6 ± 9.9 × 10-8/bp in human cells. These error rates were modified by various factors including aging, mutagen treatment and gene modifications. For example, the deletion or modification of several related genes increased the error rate substantially in both yeast and human cells. This research highlights the evolutionary conservation of factors that control the fidelity of transcription. Additionally, these experiments provide a reasonable estimate of the error rate of transcription in human cells and identify disease alleles in a subunit of RNA polymerase II that display error-prone transcription. Finally, we provide evidence suggesting that the error rate and spectrum of transcription co-evolved with our genetic code.
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Affiliation(s)
- Claire Chung
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Bert M Verheijen
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Zoe Navapanich
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Eric G McGann
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Sarah Shemtov
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Guan-Ju Lai
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Payal Arora
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Atif Towheed
- Children's hospital of Philadelphia, Center for Mitochondrial and Epigenomic Medicine, Philadelphia, PA, USA
| | - Suraiya Haroon
- Children's hospital of Philadelphia, Center for Mitochondrial and Epigenomic Medicine, Philadelphia, PA, USA
| | - Agnes Holczbauer
- Children's hospital of Philadelphia, Center for Mitochondrial and Epigenomic Medicine, Philadelphia, PA, USA
| | - Sharon Chang
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Zarko Manojlovic
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Stephen Simpson
- College of Life Sciences and Agriculture, University of New Hampshire, Durham, NH, USA
| | - Kelley W Thomas
- College of Life Sciences and Agriculture, University of New Hampshire, Durham, NH, USA
| | - Craig Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter van Hasselt
- Department of Metabolic Disease, University of Utrecht, Utrecht, the Netherlands
| | - Marc Timmers
- Department of Urology, Medical Center - University of Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Dorothy Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA
| | - Lin Chen
- Department of Molecular and Cellular Biology, University of Southern California, Los Angeles, CA, USA
| | - Jean-Franćois Gout
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Marc Vermulst
- School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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4
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Roa-Linares VC, Escudero-Flórez M, Vicente-Manzanares M, Gallego-Gómez JC. Host Cell Targets for Unconventional Antivirals against RNA Viruses. Viruses 2023; 15:v15030776. [PMID: 36992484 PMCID: PMC10058429 DOI: 10.3390/v15030776] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/12/2023] [Accepted: 02/28/2023] [Indexed: 03/31/2023] Open
Abstract
The recent COVID-19 crisis has highlighted the importance of RNA-based viruses. The most prominent members of this group are SARS-CoV-2 (coronavirus), HIV (human immunodeficiency virus), EBOV (Ebola virus), DENV (dengue virus), HCV (hepatitis C virus), ZIKV (Zika virus), CHIKV (chikungunya virus), and influenza A virus. With the exception of retroviruses which produce reverse transcriptase, the majority of RNA viruses encode RNA-dependent RNA polymerases which do not include molecular proofreading tools, underlying the high mutation capacity of these viruses as they multiply in the host cells. Together with their ability to manipulate the immune system of the host in different ways, their high mutation frequency poses a challenge to develop effective and durable vaccination and/or treatments. Consequently, the use of antiviral targeting agents, while an important part of the therapeutic strategy against infection, may lead to the selection of drug-resistant variants. The crucial role of the host cell replicative and processing machinery is essential for the replicative cycle of the viruses and has driven attention to the potential use of drugs directed to the host machinery as therapeutic alternatives to treat viral infections. In this review, we discuss small molecules with antiviral effects that target cellular factors in different steps of the infectious cycle of many RNA viruses. We emphasize the repurposing of FDA-approved drugs with broad-spectrum antiviral activity. Finally, we postulate that the ferruginol analog (18-(phthalimide-2-yl) ferruginol) is a potential host-targeted antiviral.
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Affiliation(s)
- Vicky C Roa-Linares
- Molecular and Translation Medicine Group, University of Antioquia, Medellin 050010, Colombia
| | - Manuela Escudero-Flórez
- Molecular and Translation Medicine Group, University of Antioquia, Medellin 050010, Colombia
| | - Miguel Vicente-Manzanares
- Molecular Mechanisms Program, Centro de Investigación del Cáncer, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain
| | - Juan C Gallego-Gómez
- Molecular and Translation Medicine Group, University of Antioquia, Medellin 050010, Colombia
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5
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Li X, Chou T. Stochastic dynamics and ribosome-RNAP interactions in transcription-translation coupling. Biophys J 2023; 122:254-266. [PMID: 36199250 PMCID: PMC9822797 DOI: 10.1016/j.bpj.2022.09.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 01/11/2023] Open
Abstract
Under certain cellular conditions, transcription and mRNA translation in prokaryotes appear to be "coupled," in which the formation of mRNA transcript and production of its associated protein are temporally correlated. Such transcription-translation coupling (TTC) has been evoked as a mechanism that speeds up the overall process, provides protection against premature termination, and/or regulates the timing of transcript and protein formation. What molecular mechanisms underlie ribosome-RNAP coupling and how they can perform these functions have not been explicitly modeled. We develop and analyze a continuous-time stochastic model that incorporates ribosome and RNAP elongation rates, initiation and termination rates, RNAP pausing, and direct ribosome and RNAP interactions (exclusion and binding). Our model predicts how distributions of delay times depend on these molecular features of transcription and translation. We also propose additional measures for TTC: a direct ribosome-RNAP binding probability and the fraction of time the translation-transcription process is "protected" from attack by transcription-terminating proteins. These metrics quantify different aspects of TTC and differentially depend on parameters of known molecular processes. We use our metrics to reveal how and when our model can exhibit either acceleration or deceleration of transcription, as well as protection from termination. Our detailed mechanistic model provides a basis for designing new experimental assays that can better elucidate the mechanisms of TTC.
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Affiliation(s)
- Xiangting Li
- Department of Computational Medicine, University of California, Los Angeles, Los Angeles, California
| | - Tom Chou
- Department of Computational Medicine, University of California, Los Angeles, Los Angeles, California; Department of Mathematics, University of California, Los Angeles, Los Angeles, California.
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6
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Bhardwaj V, Sharma N. Absence of the Rpb9 subunit of RNA polymerase II reduces the chronological life span in fission yeast. J Basic Microbiol 2022; 62:900-910. [PMID: 35618649 DOI: 10.1002/jobm.202200036] [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: 01/23/2022] [Revised: 04/04/2022] [Accepted: 05/14/2022] [Indexed: 11/07/2022]
Abstract
Fission yeast RNA polymerase II consists of 12 subunits, Rpb1-Rpb12. Among these subunits, Rpb9 is the only subunit whose absence does not cause lethality under optimum growth conditions in fission yeast. However, an rpb9 null fission yeast mutant exhibits a slow-growth phenotype under optimum growth conditions and a defect in survival under environmental and genotoxic stress conditions. To further gain an understanding of its physiological roles, in the present study we have elucidated the role of the Rpb9 subunit in chronological aging using fission yeast as the model organism. Our results provide evidence that the absence of Rpb9 reduces the chronological life span in fission yeast. Our data further shows that lack of Rpb9 in fission yeast causes oxidative stress sensitivity and accumulation of reactive oxygen species during the stationary phase. Our domain mapping experiments have demonstrated that the Rpb9 region encompassing its amino-terminal zinc finger domain and the central linker region is important for the role of Rpb9 in chronological aging. Finally, we also show that expression of the budding yeast or human Rpb9 ortholog can functionally complement the reduced chronological life span phenotype of the fission yeast rpb9 deletion mutant. Taken together, our study has identified a new role of the Rpb9 subunit in chronological aging.
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Affiliation(s)
- Vaibhav Bhardwaj
- University School of Biotechnology (USBT), Guru Gobind Singh Indraprastha University, Dwarka, New Delhi, India
| | - Nimisha Sharma
- University School of Biotechnology (USBT), Guru Gobind Singh Indraprastha University, Dwarka, New Delhi, India
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7
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RNA polymerase I (Pol I) lobe-binding subunit Rpa12.2 promotes RNA cleavage and proofreading. J Biol Chem 2022; 298:101862. [PMID: 35341765 PMCID: PMC9108883 DOI: 10.1016/j.jbc.2022.101862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 03/13/2022] [Accepted: 03/17/2022] [Indexed: 11/23/2022] Open
Abstract
Elongating nuclear RNA polymerases (Pols) frequently pause, backtrack, and are then reactivated by endonucleolytic cleavage. Pol backtracking and RNA cleavage are also crucial for proofreading, which contributes to transcription fidelity. RNA polymerase I (Pol I) of the yeast Saccharomyces cerevisiae synthesizes exclusively 35S rRNA, the precursor transcript of mature ribosomal 5.8S, 18S, and 25S rRNA. Pol I contains the specific heterodimeric subunits Rpa34.5/49 and subunit Rpa12.2, which have been implicated in RNA cleavage and elongation activity, respectively. These subunits are associated with the Pol I lobe structure and encompass different structural domains, but the contribution of these domains to RNA elongation is unclear. Here, we used Pol I mutants or reconstituted Pol I enzymes to study the effects of these subunits and/or their distinct domains on RNA cleavage, backtracking, and transcription fidelity in defined in vitro systems. Our findings suggest that the presence of the intact C-terminal domain of Rpa12.2 is sufficient to support the cleavage reaction, but that the N-terminal domains of Rpa12.2 and the heterodimer facilitate backtracking and RNA cleavage. Since both N-terminal and C-terminal domains of Rpa12.2 were also required to faithfully incorporate NTPs in the growing RNA chain, efficient backtracking and RNA cleavage might be a prerequisite for transcription fidelity. We propose that RNA Pols containing efficient RNA cleavage activity are able to add and remove nucleotides until the matching nucleotide supports RNA chain elongation, whereas cleavage-deficient enzymes can escape this proofreading process by incorporating incorrect nucleotides.
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8
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Deletion of the non-essential Rpb9 subunit of RNA polymerase II results in pleiotropic phenotypes in Schizosaccharomyces pombe. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140654. [PMID: 33775921 DOI: 10.1016/j.bbapap.2021.140654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 10/21/2022]
Abstract
Schizosaccharomyces pombe RNA polymerase II comprises twelve different subunits. Its Rpb9 subunit comprises 113 amino acids, and is the only non-essential subunit of S. pombe RNA polymerase II. However, its functions have not been studied in S. pombe. The results presented in this study demonstrate that Rpb9 is involved in regulating growth under optimum and certain stress conditions in S. pombe. To further address the role (s) of various domains of this subunit in regulating these phenotypes, deletion mutant analysis was done. We observed that the region spanning 1-74 amino acids, encompassing the amino-terminal zinc finger domain and the linker region of Rpb9 was able to rescue the phenotypes associated with rpb9+deletion. We also demonstrate that the functions of this subunit are only partially conserved among yeast and humans. Our computational biology approaches provide a structural basis for the differential role of various Rpb9 domains in S. pombe. Furthermore, using these tools we show that there has been a co-evolution of the interaction residues between the Rpb9 subunit and the two largest subunits of RNA polymerase II, allowing for a more stringent organism-specific packing. Taken together, our results have provided functional and structural insights into the Rpb9 subunit of S. pombe.
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9
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A mitogen-activated protein kinase PoxMK1 mediates regulation of the production of plant-biomass-degrading enzymes, vegetative growth, and pigment biosynthesis in Penicillium oxalicum. Appl Microbiol Biotechnol 2021; 105:661-678. [PMID: 33409610 DOI: 10.1007/s00253-020-11020-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/20/2020] [Accepted: 11/11/2020] [Indexed: 02/07/2023]
Abstract
Mitogen-activated protein kinase (MAPK) cascades are broadly conserved and play essential roles in multiple cellular processes, including fungal development, pathogenicity, and secondary metabolism. Their function, however, also exhibits species and strain specificity. Penicillium oxalicum secretes plant-biomass-degrading enzymes (PBDEs) that contribute to the carbon cycle in the natural environment and to utilization of lignocellulose in industrial processes. However, knowledge of the MAPK pathway in P. oxalicum has been relatively limited. In this study, comparative transcriptomic analysis of P. oxalicum, cultured on different carbon sources, found ten putative kinase genes with significantly modified transcriptional levels. Six of these putative kinase genes were knocked out in the parental strain ∆PoxKu70, and deletion of the gene, Fus3/Kss1-like PoxMK1 (POX00158), resulted in the largest reduction (91.1%) in filter paper cellulase production. Further tests revealed that the mutant ∆PoxMK1 lost 37.1 to 92.2% of PBDE production, under both submerged- and solid-state fermentation conditions, compared with ∆PoxKu70. In addition, the mutant ∆PoxMK1 had reduced vegetative growth and increased pigment biosynthesis. Comparative transcriptomic analysis showed that PoxMK1 deletion from P. oxalicum downregulated the expression of major PBDE genes and known regulatory genes such as PoxClrB and PoxCxrB, whereas the transcription of pigment biosynthesis-related genes was upregulated. Comparative phosphoproteomic analysis revealed that PoxMK1 deletion considerably modified phosphorylation of key transcription- and signal transduction-associated proteins, including transcription factors Mcm1 and Atf1, RNA polymerase II subunits Rpb1 and Rpb9, MAPK-associated Hog1 and Ste7, and cyclin-dependent kinase Kin28. These findings provide novel insights into understanding signal transduction and regulation of PBDE gene expression in fungi.Key points• PoxMK1 is involved in expression of PBDE- and pigment synthesis-related genes.• PoxMK1 is required for vegetative growth of P. oxalicum.• PoxMK1 is involved in phosphorylation of key TFs, kinases, and RNA polymerase II.
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10
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Wenck BR, Santangelo TJ. Archaeal transcription. Transcription 2020; 11:199-210. [PMID: 33112729 PMCID: PMC7714419 DOI: 10.1080/21541264.2020.1838865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022] Open
Abstract
Increasingly sophisticated biochemical and genetic techniques are unraveling the regulatory factors and mechanisms that control gene expression in the Archaea. While some similarities in regulatory strategies are universal, archaeal-specific regulatory strategies are emerging to complement a complex patchwork of shared archaeal-bacterial and archaeal-eukaryotic regulatory mechanisms employed in the archaeal domain. The prokaryotic archaea encode core transcription components with homology to the eukaryotic transcription apparatus and also share a simplified eukaryotic-like initiation mechanism, but also deploy tactics common to bacterial systems to regulate promoter usage and influence elongation-termination decisions. We review the recently established complete archaeal transcription cycle, highlight recent findings of the archaeal transcription community and detail the expanding post-initiation regulation imposed on archaeal transcription.
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Affiliation(s)
- Breanna R. Wenck
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
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11
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Ren J, Liu Y, Wang S, Wang Y, Li W, Chen S, Cui D, Yang S, Li MY, Feng B, Lai PBS, Chen GG. The FKH domain in FOXP3 mRNA frequently contains mutations in hepatocellular carcinoma that influence the subcellular localization and functions of FOXP3. J Biol Chem 2020; 295:5484-5495. [PMID: 32198183 PMCID: PMC7170510 DOI: 10.1074/jbc.ra120.012518] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/12/2020] [Indexed: 01/16/2023] Open
Abstract
The transcription factor forkhead box P3 (FOXP3) is a biomarker for regulatory T cells and can also be expressed in cancer cells, but its function in cancer appears to be divergent. The role of hepatocyte-expressed FOXP3 in hepatocellular carcinoma (HCC) is unknown. Here, we collected tumor samples and clinical information from 115 HCC patients and used five human cancer cell lines. We examined FOXP3 mRNA sequences for mutations, used a luciferase assay to assess promoter activities of FOXP3's target genes, and employed mouse tumor models to confirm in vitro results. We detected mutations in the FKH domain of FOXP3 mRNAs in 33% of the HCC tumor tissues, but in none of the adjacent nontumor tissues. None of the mutations occurred at high frequency, indicating that they occurred randomly. Notably, the mutations were not detected in the corresponding regions of FOXP3 genomic DNA, and many of them resulted in amino acid substitutions in the FKH region, altering FOXP3's subcellular localization. FOXP3 delocalization from the nucleus to the cytoplasm caused loss of transcriptional regulation of its target genes, inactivated its tumor-inhibitory capability, and changed cellular responses to histone deacetylase (HDAC) inhibitors. More complex FKH mutations appeared to be associated with worse prognosis in HCC patients. We conclude that mutations in the FKH domain of FOXP3 mRNA frequently occur in HCC and that these mutations are caused by errors in transcription and are not derived from genomic DNA mutations. Our results suggest that transcriptional mutagenesis of FOXP3 plays a role in HCC.
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Affiliation(s)
- Jianwei Ren
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute (SZRI), Chinese University of Hong Kong, Shenzhen 518057, China
| | - Yi Liu
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, Guangdong 524023, China
| | - Shanshan Wang
- School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Yu Wang
- Division of Cellular & Molecular Research, National Cancer Centre, Singapore 169610
| | - Wende Li
- Guangdong Laboratory Animals Monitoring Institute, Guangzhou 510663, China
| | - Siyu Chen
- Guangdong Laboratory Animals Monitoring Institute, Guangzhou 510663, China
| | - Dexuan Cui
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Shengli Yang
- Union Hospital Tumour Center, Wuhan 430022, China
| | - Ming-Yue Li
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510320, China
| | - Bo Feng
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Paul B S Lai
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China.
| | - George G Chen
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute (SZRI), Chinese University of Hong Kong, Shenzhen 518057, China; Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, Guangdong 524023, China; Department of Otorhinolaryngology, Head and Neck Surgery, Chinese University of Hong Kong, Hong Kong, China.
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12
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Warthi G, Fournier PE, Seligmann H. Systematic Nucleotide Exchange Analysis of ESTs From the Human Cancer Genome Project Report: Origins of 347 Unknown ESTs Indicate Putative Transcription of Non-Coding Genomic Regions. Front Genet 2020; 11:42. [PMID: 32117454 PMCID: PMC7027195 DOI: 10.3389/fgene.2020.00042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/15/2020] [Indexed: 12/16/2022] Open
Abstract
Expressed sequence tags (ESTs) provide an imprint of cellular RNA diversity irrespectively of sequence homology with template genomes. NCBI databases include many unknown RNAs from various normal and cancer cells. These are usually ignored assuming sequencing artefacts or contamination due to their lack of sequence homology with template DNA. Here, we report genomic origins of 347 ESTs previously assumed artefacts/unknown, from the FAPESP/LICR Human Cancer Genome Project. EST template detection uses systematic nucleotide exchange analyses called swinger transformations. Systematic nucleotide exchanges replace systematically particular nucleotides with different nucleotides. Among 347 unknown ESTs, 51 ESTs match mitogenome transcription, 17 and 2 ESTs are from nuclear chromosome non-coding regions, and uncharacterized nuclear genes. Identified ESTs mapped on 205 protein-coding genes, 10 genes had swinger RNAs in several biosamples. Whole cell transcriptome searches for 17 ESTs mapping on non-coding regions confirmed their transcription. The 10 swinger-transcribed genes identified more than once associate with cancer induction and progression, suggesting swinger transformation occurs mainly in highly transcribed genes. Swinger transformation is a unique method to identify noncanonical RNAs obtained from NGS, which identifies putative ncRNA transcribed regions. Results suggest that swinger transcription occurs in highly active genes in normal and genetically unstable cancer cells.
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Affiliation(s)
- Ganesh Warthi
- Aix Marseille Univ, IRD, APHM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Pierre-Edouard Fournier
- Aix Marseille Univ, IRD, APHM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Hervé Seligmann
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel.,Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical & Labcom CNRS/UGA/OrangeLabs Telecoms4Health, La Tronche, France
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13
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Warthi G, Seligmann H. Transcripts with systematic nucleotide deletion of 1-12 nucleotide in human mitochondrion suggest potential non-canonical transcription. PLoS One 2019; 14:e0217356. [PMID: 31120958 PMCID: PMC6532905 DOI: 10.1371/journal.pone.0217356] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 11/22/2022] Open
Abstract
Raw transcriptomic data contain numerous RNA reads whose homology with template DNA doesn't match canonical transcription. Transcriptome analyses usually ignore such noncanonical RNA reads. Here, analyses search for noncanonical mitochondrial RNAs systematically deleting 1 to 12 nucleotides after each transcribed nucleotide triplet, producing deletion-RNAs (delRNAs). We detected delRNAs in the human whole cell and purified mitochondrial transcriptomes, and in Genbank's human EST database corresponding to systematic deletions of 1 to 12 nucleotides after each transcribed trinucleotide. DelRNAs detected in both transcriptomes mapped along with 55.63% of the EST delRNAs. A bias exists for delRNAs covering identical mitogenomic regions in both transcriptomic and EST datasets. Among 227 delRNAs detected in these 3 datasets, 81.1% and 8.4% of delRNAs were mapped on mitochondrial coding and hypervariable region 2 of dloop. Del-transcription analyses of GenBank's EST database confirm observations from whole cell and purified mitochondrial transcriptomes, eliminating the possibility that detected delRNAs are false positives matches, cytosolic DNA/RNA nuclear contamination or sequencing artefacts. These detected delRNAs are enriched in frameshift-inducing homopolymers and are poor in frameshift-preventing circular code codons (a set of 20 codons which regulate reading frame detection, over- and underrepresented in coding and other frames of genes, respectively) suggesting a motif-based regulation of non-canonical transcription. These findings show that rare non-canonical transcripts exist. Such non canonical del-transcription does increases mitochondrial coding potential and non-coding regulation of intracellular mechanisms, and could explain the dark DNA conundrum.
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Affiliation(s)
- Ganesh Warthi
- Aix-Marseille Université, IRD, VITROME, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Hervé Seligmann
- Aix-Marseille Université, IRD, MEPHI, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Marseille, France
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
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14
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Tafur L, Sadian Y, Hanske J, Wetzel R, Weis F, Müller CW. The cryo-EM structure of a 12-subunit variant of RNA polymerase I reveals dissociation of the A49-A34.5 heterodimer and rearrangement of subunit A12.2. eLife 2019; 8:43204. [PMID: 30913026 PMCID: PMC6435322 DOI: 10.7554/elife.43204] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 03/09/2019] [Indexed: 11/13/2022] Open
Abstract
RNA polymerase (Pol) I is a 14-subunit enzyme that solely transcribes pre-ribosomal RNA. Cryo-electron microscopy (EM) structures of Pol I initiation and elongation complexes have given first insights into the molecular mechanisms of Pol I transcription. Here, we present cryo-EM structures of yeast Pol I elongation complexes (ECs) bound to the nucleotide analog GMPCPP at 3.2 to 3.4 Å resolution that provide additional insight into the functional interplay between the Pol I-specific transcription-like factors A49-A34.5 and A12.2. Strikingly, most of the nucleotide-bound ECs lack the A49-A34.5 heterodimer and adopt a Pol II-like conformation, in which the A12.2 C-terminal domain is bound in a previously unobserved position at the A135 surface. Our structural and biochemical data suggest a mechanism where reversible binding of the A49-A34.5 heterodimer could contribute to the regulation of Pol I transcription initiation and elongation.
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Affiliation(s)
- Lucas Tafur
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for joint PhD degree, European Molecular Biology Laboratory and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Yashar Sadian
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jonas Hanske
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Rene Wetzel
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Felix Weis
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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15
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Sein H, Reinmets K, Peil K, Kristjuhan K, Värv S, Kristjuhan A. Rpb9-deficient cells are defective in DNA damage response and require histone H3 acetylation for survival. Sci Rep 2018; 8:2949. [PMID: 29440683 PMCID: PMC5811553 DOI: 10.1038/s41598-018-21110-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/29/2018] [Indexed: 11/09/2022] Open
Abstract
Rpb9 is a non-essential subunit of RNA polymerase II that is involved in DNA transcription and repair. In budding yeast, deletion of RPB9 causes several phenotypes such as slow growth and temperature sensitivity. We found that simultaneous mutation of multiple N-terminal lysines within histone H3 was lethal in rpb9Δ cells. Our results indicate that hypoacetylation of H3 leads to inefficient repair of DNA double-strand breaks, while activation of the DNA damage checkpoint regulators γH2A and Rad53 is suppressed in Rpb9-deficient cells. Combination of H3 hypoacetylation with the loss of Rpb9 leads to genomic instability, aberrant segregation of chromosomes in mitosis, and eventually to cell death. These results indicate that H3 acetylation becomes essential for efficient DNA repair and cell survival if a DNA damage checkpoint is defective.
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Affiliation(s)
- Henel Sein
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Kristina Reinmets
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Kadri Peil
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Kersti Kristjuhan
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Signe Värv
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia.,Department of Biosciences, Section for Biochemistry and Molecular Biology, University of Oslo, Blindernveien 31, 0371, Oslo, Norway
| | - Arnold Kristjuhan
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia.
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16
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Li W, Li S. Facilitators and Repressors of Transcription-coupled DNA Repair in Saccharomyces cerevisiae. Photochem Photobiol 2016; 93:259-267. [PMID: 27796045 DOI: 10.1111/php.12655] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/12/2016] [Indexed: 12/11/2022]
Abstract
Nucleotide excision repair is a well-conserved DNA repair pathway that removes bulky and/or helix-distorting DNA lesions, such as UV-induced cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts. Transcription-coupled repair (TCR) is a subpathway of nucleotide excision repair that is dedicated to rapid removal of DNA lesions in the transcribed strand of actively transcribed genes. In eukaryotic cells, TCR is triggered by RNA polymerase II (RNAP II). Rad26, a DNA-dependent ATPase, Rpb9, a nonessential subunit of RNAP II, and Sen1, a 5' to 3' RNA/DNA and DNA helicase, have been shown to facilitate TCR in Saccharomyces cerevisiae. In contrast, a number of factors have also been found to repress TCR in the yeast. These TCR repressors include Rpb4, another nonessential subunit of RNAP II, Spt4/5, a transcription elongation factor complex, and the RNAP II-associated factor 1 complex (PAFc). It appears that the eukaryotic TCR process involves intricate interplays of RNAP II with TCR facilitators and repressors. In this minireview, we summarize recent advances in TCR in S. cerevisiae.
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Affiliation(s)
- Wentao Li
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Shisheng Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
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17
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Fungtammasan A, Tomaszkiewicz M, Campos-Sánchez R, Eckert KA, DeGiorgio M, Makova KD. Reverse Transcription Errors and RNA-DNA Differences at Short Tandem Repeats. Mol Biol Evol 2016; 33:2744-58. [PMID: 27413049 PMCID: PMC5026258 DOI: 10.1093/molbev/msw139] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Transcript variation has important implications for organismal function in health and disease. Most transcriptome studies focus on assessing variation in gene expression levels and isoform representation. Variation at the level of transcript sequence is caused by RNA editing and transcription errors, and leads to nongenetically encoded transcript variants, or RNA–DNA differences (RDDs). Such variation has been understudied, in part because its detection is obscured by reverse transcription (RT) and sequencing errors. It has only been evaluated for intertranscript base substitution differences. Here, we investigated transcript sequence variation for short tandem repeats (STRs). We developed the first maximum-likelihood estimator (MLE) to infer RT error and RDD rates, taking next generation sequencing error rates into account. Using the MLE, we empirically evaluated RT error and RDD rates for STRs in a large-scale DNA and RNA replicated sequencing experiment conducted in a primate species. The RT error rates increased exponentially with STR length and were biased toward expansions. The RDD rates were approximately 1 order of magnitude lower than the RT error rates. The RT error rates estimated with the MLE from a primate data set were concordant with those estimated with an independent method, barcoded RNA sequencing, from a Caenorhabditis elegans data set. Our results have important implications for medical genomics, as STR allelic variation is associated with >40 diseases. STR nonallelic transcript variation can also contribute to disease phenotype. The MLE and empirical rates presented here can be used to evaluate the probability of disease-associated transcripts arising due to RDD.
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Affiliation(s)
- Arkarachai Fungtammasan
- Integrative Biosciences, Bioinformatics and Genomics Option, Pennsylvania State University Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University Huck Institute of Genome Sciences, Pennsylvania State University
| | - Marta Tomaszkiewicz
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University
| | - Rebeca Campos-Sánchez
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University
| | - Kristin A Eckert
- Center for Medical Genomics, Pennsylvania State University Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, The Pennsylvania State University College of Medicine
| | - Michael DeGiorgio
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University Institute for CyberScience, Pennsylvania State University
| | - Kateryna D Makova
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University Huck Institute of Genome Sciences, Pennsylvania State University
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18
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Kaster BC, Knippa KC, Kaplan CD, Peterson DO. RNA Polymerase II Trigger Loop Mobility: INDIRECT EFFECTS OF Rpb9. J Biol Chem 2016; 291:14883-95. [PMID: 27226557 DOI: 10.1074/jbc.m116.714394] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Indexed: 01/08/2023] Open
Abstract
Rpb9 is a conserved RNA polymerase II (pol II) subunit, the absence of which confers alterations to pol II enzymatic properties and transcription fidelity. It has been suggested previously that Rpb9 affects mobility of the trigger loop (TL), a structural element of Rpb1 that moves in and out of the active site with each elongation cycle. However, a biochemical mechanism for this effect has not been defined. We find that the mushroom toxin α-amanitin, which inhibits TL mobility, suppresses the effect of Rpb9 on NTP misincorporation, consistent with a role for Rpb9 in this process. Furthermore, we have identified missense alleles of RPB9 in yeast that suppress the severe growth defect caused by rpb1-G730D, a substitution within Rpb1 α-helix 21 (α21). These alleles suggest a model in which Rpb9 indirectly affects TL mobility by anchoring the position of α21, with which the TL directly interacts during opening and closing. Amino acid substitutions in Rpb9 or Rpb1 that disrupt proposed anchoring interactions resulted in phenotypes shared by rpb9Δ strains, including increased elongation rate in vitro Combinations of rpb9Δ with the fast rpb1 alleles that we identified did not result in significantly faster in vitro misincorporation rates than those resulting from rpb9Δ alone, and this epistasis is consistent with the idea that defects caused by the rpb1 alleles are related mechanistically to the defects caused by rpb9Δ. We conclude that Rpb9 supports intra-pol II interactions that modulate TL function and thus pol II enzymatic properties.
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Affiliation(s)
- Benjamin C Kaster
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Kevin C Knippa
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Craig D Kaplan
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - David O Peterson
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
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19
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Carey LB. RNA polymerase errors cause splicing defects and can be regulated by differential expression of RNA polymerase subunits. eLife 2015; 4. [PMID: 26652005 PMCID: PMC4868539 DOI: 10.7554/elife.09945] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/26/2015] [Indexed: 12/26/2022] Open
Abstract
Errors during transcription may play an important role in determining cellular phenotypes: the RNA polymerase error rate is >4 orders of magnitude higher than that of DNA polymerase and errors are amplified >1000-fold due to translation. However, current methods to measure RNA polymerase fidelity are low-throughout, technically challenging, and organism specific. Here I show that changes in RNA polymerase fidelity can be measured using standard RNA sequencing protocols. I find that RNA polymerase is error-prone, and these errors can result in splicing defects. Furthermore, I find that differential expression of RNA polymerase subunits causes changes in RNA polymerase fidelity, and that coding sequences may have evolved to minimize the effect of these errors. These results suggest that errors caused by RNA polymerase may be a major source of stochastic variability at the level of single cells.
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Affiliation(s)
- Lucas B Carey
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
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20
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Zhou M, Law JA. RNA Pol IV and V in gene silencing: Rebel polymerases evolving away from Pol II's rules. CURRENT OPINION IN PLANT BIOLOGY 2015; 27:154-64. [PMID: 26344361 PMCID: PMC4618083 DOI: 10.1016/j.pbi.2015.07.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/15/2015] [Accepted: 07/19/2015] [Indexed: 05/19/2023]
Abstract
Noncoding RNAs regulate gene expression at both the transcriptional and post-transcriptional levels, and play critical roles in development, imprinting and the maintenance of genome integrity in eukaryotic organisms [1,2,3]. Therefore, it is important to understand how the production of such RNAs are controlled. In addition to the three canonical DNA dependent RNA polymerases (Pol) Pol I, II and III, two non-redundant plant-specific RNA polymerases, Pol IV and Pol V, have been identified and shown to generate noncoding RNAs that are required for transcriptional gene silencing via the RNA-directed DNA methylation (RdDM) pathway. Thus, somewhat paradoxically, transcription is required for gene silencing. This paradox extends beyond plants, as silencing pathways in yeast, fungi, flies, worms, and mammals also require transcriptional machinery [4,5]. As plants have evolved specialized RNA polymerases to carry out gene silencing in a manner that is separate from the essential roles of Pol II, their characterization offers unique insights into how RNA polymerases facilitate gene silencing. In this review, we focus on the mechanisms of Pol IV and Pol V function, including their compositions, their transcripts, and their modes of recruitment to chromatin.
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Affiliation(s)
- Ming Zhou
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Julie A Law
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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21
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A genetic assay for transcription errors reveals multilayer control of RNA polymerase II fidelity. PLoS Genet 2014; 10:e1004532. [PMID: 25232834 PMCID: PMC4168980 DOI: 10.1371/journal.pgen.1004532] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 06/11/2014] [Indexed: 11/19/2022] Open
Abstract
We developed a highly sensitive assay to detect transcription errors in vivo. The assay is based on suppression of a missense mutation in the active site tyrosine in the Cre recombinase. Because Cre acts as tetramer, background from translation errors are negligible. Functional Cre resulting from rare transcription errors that restore the tyrosine codon can be detected by Cre-dependent rearrangement of reporter genes. Hence, transient transcription errors are captured as stable genetic changes. We used this Cre-based reporter to screen for mutations of Saccharomyces cerevisiae RPB1 (RPO21) that increase the level of misincorporation during transcription. The mutations are in three domains of Rpb1, the trigger loop, the bridge helix, and in sites involved in binding to TFIIS. Biochemical characterization demonstrates that these variants have elevated misincorporation, and/or ability to extend mispaired bases, or defects in TFIIS mediated editing.
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