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La Rocca G, Cavalieri V. Roles of the Core Components of the Mammalian miRISC in Chromatin Biology. Genes (Basel) 2022; 13:414. [PMID: 35327968 PMCID: PMC8954937 DOI: 10.3390/genes13030414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 12/16/2022] Open
Abstract
The Argonaute (AGO) and the Trinucleotide Repeat Containing 6 (TNRC6) family proteins are the core components of the mammalian microRNA-induced silencing complex (miRISC), the machinery that mediates microRNA function in the cytoplasm. The cytoplasmic miRISC-mediated post-transcriptional gene repression has been established as the canonical mechanism through which AGO and TNRC6 proteins operate. However, growing evidence points towards an additional mechanism through which AGO and TNRC6 regulate gene expression in the nucleus. While several mechanisms through which miRISC components function in the nucleus have been described, in this review we aim to summarize the major findings that have shed light on the role of AGO and TNRC6 in mammalian chromatin biology and on the implications these novel mechanisms may have in our understanding of regulating gene expression.
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Affiliation(s)
- Gaspare La Rocca
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
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2
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Singh S, Kailasam S, Lo JC, Yeh KC. Histone H3 lysine4 trimethylation-regulated GRF11 expression is essential for the iron-deficiency response in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2021; 230:244-258. [PMID: 33274450 DOI: 10.1111/nph.17130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/26/2020] [Indexed: 05/21/2023]
Abstract
Iron (Fe) homeostasis in plants is controlled by both transcription factors (TFs) and chromatin remodeling through histone modification. To date, few studies have reported the existence of histone modification in maintaining the Fe-deficiency response. However, the reports that do exist shed light on various histone modifications, but knowledge of the activation mark in Fe-deficiency response is lacking. By using a forward genetics approach, we identified a crucial allele for Fe-deficiency response, NON-RESPONSE TO Fe-DEFICIENCY2 (NRF2), previously described as EARLY FLOWERING8 (ELF8) associated with an activation mark on histone modification, histone H3 lysine4 trimethylation. In the nrf2-1 mutant, a point mutation at ELF8T404I , exhibits impaired expression of GENERAL REGULATORY FACTOR11 (GRF11) and downstream genes in the Fe-uptake pathway. In vivo chromatin immunoprecipitation revealed that in roots, NRF2/ELF8 is essential for the expression of GRF11 for Fe-deficiency response, whereas in shoots, NRF2/ELF8 regulates FLOWERING LOCUS C (FLC) expression for flowering time control. In summary, a key factor, NRF2/ELF8, involved in epigenetic regulation essential for both flowering time control and Fe-deficiency response is uncovered.
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Affiliation(s)
- Surjit Singh
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei, 11529, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Sakthivel Kailasam
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Jing-Chi Lo
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Kuo-Chen Yeh
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei, 11529, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, 40227, Taiwan
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3
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Developing small activating RNA as a therapeutic: current challenges and promises. Ther Deliv 2020; 10:151-164. [PMID: 30909853 DOI: 10.4155/tde-2018-0061] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
RNA activation (RNAa) allows specific gene upregulation mediated by a small activating RNA (saRNA). Harnessing this process would help in developing novel therapeutics for undruggable diseases. Since its discovery in mid 2000s, improvements of saRNA design, synthetic chemistry and understanding of the biology have matured the way to apply RNAa. Indeed, MiNA therapeutics Ltd has conducted the first RNAa clinical trial for advanced hepatocellular carcinoma patients with promising outcomes. However, to fully realize the RNAa potential better saRNA delivery strategies are needed to target other diseases. Currently, saRNA can be delivered in vivo by lipid nanoparticles, dendrimers, lipid and polymer hybrids and aptamers. Further developing these delivery technologies and novel application of RNAa will prove to be invaluable for new treatment development.
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4
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Yeast PAF1 complex counters the pol III accumulation and replication stress on the tRNA genes. Sci Rep 2019; 9:12892. [PMID: 31501524 PMCID: PMC6733944 DOI: 10.1038/s41598-019-49316-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/21/2019] [Indexed: 12/13/2022] Open
Abstract
The RNA polymerase (pol) III transcribes mostly short, house-keeping genes, which produce stable, non-coding RNAs. The tRNAs genes, highly transcribed by pol III in vivo are known replication fork barriers. One of the transcription factors, the PAF1C (RNA polymerase II associated factor 1 complex) is reported to associate with pol I and pol II and influence their transcription. We found low level PAF1C occupancy on the yeast pol III-transcribed genes, which is not correlated with nucleosome positions, pol III occupancy and transcription. PAF1C interacts with the pol III transcription complex and causes pol III loss from the genes under replication stress. Genotoxin exposure causes pol III but not Paf1 loss from the genes. In comparison, Paf1 deletion leads to increased occupancy of pol III, γ-H2A and DNA pol2 in gene-specific manner. Paf1 restricts the accumulation of pol III by influencing the pol III pause on the genes, which reduces the pol III barrier to the replication fork progression.
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5
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Karmakar S, Dey P, Vaz AP, Bhaumik SR, Ponnusamy MP, Batra SK. PD2/PAF1 at the Crossroads of the Cancer Network. Cancer Res 2018; 78:313-319. [PMID: 29311159 DOI: 10.1158/0008-5472.can-17-2175] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/29/2017] [Accepted: 11/06/2017] [Indexed: 12/31/2022]
Abstract
Pancreatic differentiation 2 (PD2)/RNA polymerase II-associated factor 1 (PAF1) is the core subunit of the human PAF1 complex (PAF1C) that regulates the promoter-proximal pausing of RNA polymerase II as well as transcription elongation and mRNA processing and coordinates events in mRNA stability and quality control. As an integral part of its transcription-regulatory function, PD2/PAF1 plays a role in posttranslational histone covalent modifications as well as regulates expression of critical genes of the cell-cycle machinery. PD2/PAF1 alone, and as a part of PAF1C, provides distinct roles in the maintenance of self-renewal of embryonic stem cells and cancer stem cells, and in lineage differentiation. Thus, PD2/PAF1 malfunction or its altered abundance is likely to affect normal cellular functions, leading to disease states. Indeed, PD2/PAF1 is found to be upregulated in poorly differentiated pancreatic cancer cells and has the capacity for neoplastic transformation when ectopically expressed in mouse fibroblast cells. Likewise, PD2/PAF1 is upregulated in pancreatic and ovarian cancer stem cells. Here, we concisely describe multifaceted roles of PD2/PAF1 associated with oncogenic transformation and implicate PD2/PAF1 as an attractive target for therapeutic development to combat malignancy. Cancer Res; 78(2); 313-9. ©2018 AACR.
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Affiliation(s)
- Saswati Karmakar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Parama Dey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Arokia P Vaz
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois
| | - Moorthy P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska.,Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska. .,Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska
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6
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Li LC. Small RNA-Guided Transcriptional Gene Activation (RNAa) in Mammalian Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017. [DOI: 10.1007/978-981-10-4310-9_1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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7
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Zhang Y, Najmi SM, Schneider DA. Transcription factors that influence RNA polymerases I and II: To what extent is mechanism of action conserved? BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:246-255. [PMID: 27989933 DOI: 10.1016/j.bbagrm.2016.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/07/2016] [Accepted: 10/25/2016] [Indexed: 01/05/2023]
Abstract
In eukaryotic cells, nuclear RNA synthesis is accomplished by at least three unique, multisubunit RNA polymerases. The roles of these enzymes are generally partitioned into the synthesis of the three major classes of RNA: rRNA, mRNA, and tRNA for RNA polymerases I, II, and III respectively. Consistent with their unique cellular roles, each enzyme has a complement of specialized transcription factors and enzymatic properties. However, not all transcription factors have evolved to affect only one eukaryotic RNA polymerase. In fact, many factors have been shown to influence the activities of multiple nuclear RNA polymerases. This review focuses on a subset of these factors, specifically addressing the mechanisms by which these proteins influence RNA polymerases I and II.
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Affiliation(s)
- Yinfeng Zhang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Saman M Najmi
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - David A Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
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8
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Jahani-Asl A, Cheng C, Zhang C, Bonni A. Pathogenesis of Börjeson-Forssman-Lehmann syndrome: Insights from PHF6 function. Neurobiol Dis 2016; 96:227-235. [PMID: 27633282 DOI: 10.1016/j.nbd.2016.09.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/07/2016] [Accepted: 09/07/2016] [Indexed: 02/07/2023] Open
Abstract
Intellectual disability encompasses a large set of neurodevelopmental disorders of cognition that are more common in males than females. Although mutations in over 100 X-linked genes associated to intellectual disability have been identified, only a few X-linked intellectual disability proteins have been intensively studied. Hence, the molecular mechanisms underlying the majority of X-linked intellectual disability disorders remain poorly understood. A substantial fraction of X-linked intellectual disability genes encode nuclear proteins, suggesting that elucidating their functions in the regulation of transcription may provide novel insights into the pathogenesis of intellectual disability. Recent studies have uncovered mechanisms by which mutations of the gene encoding plant homeodomain (PHD)-like finger protein 6 (PHF6) contribute to the pathogenesis of the X-linked intellectual disability disorder Börjeson-Forssman-Lehmann syndrome (BFLS). PHF6 plays a critical role in the migration of neurons in the mouse cerebral cortex in vivo, and patient-specific mutations disrupt the ability of PHF6 to promote neuronal migration. Interestingly, PHF6 physically associates with the PAF1 transcriptional elongation complex and thereby drives neuronal migration in the cerebral cortex. PHF6 also interacts with the NuRD chromatin remodeling complex and with the nucleolar transcriptional regulator UBF, though the biological role of these interactions remains to be characterized. In other studies, PHF6 mRNA has been identified as the target of the microRNA miR-128 in the cerebral cortex, providing new insights into regulation of PHF6 function in neuronal migration. Importantly, deregulation of PHF6 function in neuronal migration triggers the formation of white matter heterotopias that harbor neuronal hyperexcitability, which may be relevant to the pathogenesis of intellectual disability and seizures in BFLS. Collectively, these studies are beginning to provide key insights into the molecular pathogenesis of BFLS.
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Affiliation(s)
- Arezu Jahani-Asl
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA; Department of Oncology, Faculty of Medicine, McGill University, Montreal, QC H3T 1E2, Canada; Lady Davis Research Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada
| | - Cheng Cheng
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA
| | - Chi Zhang
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA
| | - Azad Bonni
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA.
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9
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Portnoy V, Lin SHS, Li KH, Burlingame A, Hu ZH, Li H, Li LC. saRNA-guided Ago2 targets the RITA complex to promoters to stimulate transcription. Cell Res 2016; 26:320-35. [PMID: 26902284 PMCID: PMC4783471 DOI: 10.1038/cr.2016.22] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 10/22/2015] [Accepted: 01/12/2016] [Indexed: 12/21/2022] Open
Abstract
Small activating RNAs (saRNAs) targeting specific promoter regions are able to stimulate gene expression at the transcriptional level, a phenomenon known as RNA activation (RNAa). It is known that RNAa depends on Ago2 and is associated with epigenetic changes at the target promoters. However, the precise molecular mechanism of RNAa remains elusive. Using human CDKN1A (p21) as a model gene, we characterized the molecular nature of RNAa. We show that saRNAs guide Ago2 to and associate with target promoters. saRNA-loaded Ago2 facilitates the assembly of an RNA-induced transcriptional activation (RITA) complex, which, in addition to saRNA-Ago2 complex, includes RHA and CTR9, the latter being a component of the PAF1 complex. RITA interacts with RNA polymerase II to stimulate transcription initiation and productive elongation, accompanied by monoubiquitination of histone 2B. Our results establish the existence of a cellular RNA-guided genome-targeting and transcriptional activation mechanism and provide important new mechanistic insights into the RNAa process.
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Affiliation(s)
- Victoria Portnoy
- Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA
| | - Szu Hua Sharon Lin
- Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA
| | - Kathy H Li
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Zheng-Hui Hu
- Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA
| | - Hao Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Long-Cheng Li
- Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA.,Laboratory of Molecular Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
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10
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De Gois S, Slama P, Pietrancosta N, Erdozain AM, Louis F, Bouvrais-Veret C, Daviet L, Giros B. Ctr9, a Protein in the Transcription Complex Paf1, Regulates Dopamine Transporter Activity at the Plasma Membrane. J Biol Chem 2015; 290:17848-17862. [PMID: 26048990 DOI: 10.1074/jbc.m115.646315] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Indexed: 01/01/2023] Open
Abstract
Dopamine (DA) is a major regulator of sensorimotor and cognitive functions. The DA transporter (DAT) is the key protein that regulates the spatial and temporal activity of DA release into the synaptic cleft via the rapid reuptake of DA into presynaptic termini. Several lines of evidence have suggested that transporter-interacting proteins may play a role in DAT function and regulation. Here, we identified the tetratricopeptide repeat domain-containing protein Ctr9 as a novel DAT binding partner using a yeast two-hybrid system. We showed that Ctr9 is expressed in dopaminergic neurons and forms a stable complex with DAT in vivo via GST pulldown and co-immunoprecipitation assays. In mammalian cells co-expressing both proteins, Ctr9 partially colocalizes with DAT at the plasma membrane. This interaction between DAT and Ctr9 results in a dramatic enhancement of DAT-mediated DA uptake due to an increased number of DAT transporters at the plasma membrane. We determined that the binding of Ctr9 to DAT requires residues YKF in the first half of the DAT C terminus. In addition, we characterized Ctr9, providing new insight into this protein. Using three-dimensional modeling, we identified three novel tetratricopeptide repeat domains in the Ctr9 sequence, and based on deletion mutation experiments, we demonstrated the role of the SH2 domain of Ctr9 in nuclear localization. Our results demonstrate that Ctr9 localization is not restricted to the nucleus, as previously described for the transcription complex Paf1. Taken together, our data provide evidence that Ctr9 modulates DAT function by regulating its trafficking.
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Affiliation(s)
- Stéphanie De Gois
- INSERM U952, 75005 Paris, France; CNRS UMR 7224, 75005 Paris, France; Université Pierre et Marie Curie, Neuroscience Paris Seine, 75005 Paris, France; Douglas Hospital Research Center, Department of Psychiatry, McGill University, Montreal H4H 1R3 Quebec, Canada
| | - Patrick Slama
- INSERM U952, 75005 Paris, France; CNRS UMR 7224, 75005 Paris, France; Université Pierre et Marie Curie, Neuroscience Paris Seine, 75005 Paris, France
| | - Nicolas Pietrancosta
- Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; CNRS, UMR 8601, 75006 Paris, France
| | - Amaia M Erdozain
- INSERM U952, 75005 Paris, France; CNRS UMR 7224, 75005 Paris, France; Université Pierre et Marie Curie, Neuroscience Paris Seine, 75005 Paris, France
| | - Franck Louis
- INSERM U952, 75005 Paris, France; CNRS UMR 7224, 75005 Paris, France; Université Pierre et Marie Curie, Neuroscience Paris Seine, 75005 Paris, France
| | - Caroline Bouvrais-Veret
- INSERM U952, 75005 Paris, France; CNRS UMR 7224, 75005 Paris, France; Université Pierre et Marie Curie, Neuroscience Paris Seine, 75005 Paris, France
| | | | - Bruno Giros
- INSERM U952, 75005 Paris, France; CNRS UMR 7224, 75005 Paris, France; Université Pierre et Marie Curie, Neuroscience Paris Seine, 75005 Paris, France; Douglas Hospital Research Center, Department of Psychiatry, McGill University, Montreal H4H 1R3 Quebec, Canada.
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Cks1 enhances transcription efficiency at the GAL1 locus by linking the Paf1 complex to the 19S proteasome. EUKARYOTIC CELL 2013; 12:1192-201. [PMID: 23825181 DOI: 10.1128/ec.00151-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cks1 was originally identified based on genetic interactions with CDC28, the gene that encodes Cdk1 in the budding yeast Saccharomyces cerevisiae. Subsequent work has shown that Cks1 binds Cdc28 and modulates its activity against certain substrates. However, the Cks1/Cdc28 complex also has a role in transcriptional chromatin remodeling not related to kinase activity. In order to elucidate protein networks associated with Cks1 transcriptional functions, proteomic analysis was performed on immunoaffinity-purified Cks1, identifying a physical interaction with the Paf1 complex. Specifically, we found that the Paf1 complex component Rtf1 interacts directly with Cks1 and that this interaction is essential for efficient recruitment of Cks1 to chromatin in the context of GAL1 gene induction. We further found that Cks1 in this capacity serves as an adaptor allowing Rtf1 to recruit 19S proteasome particles, shown to be required for efficient RNA production from some rapidly inducible genes such as GAL1.
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12
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The many roles of the conserved eukaryotic Paf1 complex in regulating transcription, histone modifications, and disease states. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:116-26. [PMID: 22982193 DOI: 10.1016/j.bbagrm.2012.08.011] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/18/2012] [Accepted: 08/29/2012] [Indexed: 12/20/2022]
Abstract
The Paf1 complex was originally identified over fifteen years ago in budding yeast through its physical association with RNA polymerase II. The Paf1 complex is now known to be conserved throughout eukaryotes and is well studied for promoting RNA polymerase II transcription elongation and transcription-coupled histone modifications. Through these critical regulatory functions, the Paf1 complex participates in numerous cellular processes such as gene expression and silencing, RNA maturation, DNA repair, cell cycle progression and prevention of disease states in higher eukaryotes. In this review, we describe the historic and current research involving the eukaryotic Paf1 complex to explain the cellular roles that underlie its conservation and functional importance. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Massoni-Laporte A, Perrot M, Ponger L, Boucherie H, Guieysse-Peugeot AL. Proteome analysis of a CTR9 deficient yeast strain suggests that Ctr9 has function(s) independent of the Paf1 complex. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:759-68. [PMID: 22446411 DOI: 10.1016/j.bbapap.2012.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 02/18/2012] [Accepted: 02/25/2012] [Indexed: 11/17/2022]
Abstract
The Ctr9 protein is a member of the Paf1 complex implicated in multiple functions: transcription initiation and elongation by RNA pol II, RNA processing and histone modifications. It has also been described as a triple-helical DNA binding protein. Loss of Ctr9 results in severe phenotypes similar to the loss of Paf1p, a Paf1 complex subunit. However, the exact role of Ctr9 is not entirely established. To study the biological role of the protein Ctr9 in yeast, we used 2-D gel electrophoresis and characterized proteome alterations in a ctr9Δ mutant strain. Here we present results suggesting that Ctr9 has function distinct from its established role in the Paf1 complex. This role could be linked to its ability to bind to DNA complex structures as triplexes that may have function in regulation of gene expression.
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Dey P, Ponnusamy MP, Deb S, Batra SK. Human RNA polymerase II-association factor 1 (hPaf1/PD2) regulates histone methylation and chromatin remodeling in pancreatic cancer. PLoS One 2011; 6:e26926. [PMID: 22046413 PMCID: PMC3203178 DOI: 10.1371/journal.pone.0026926] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Accepted: 10/05/2011] [Indexed: 11/19/2022] Open
Abstract
Change in gene expression associated with pancreatic cancer could be attributed to the variation in histone posttranslational modifications leading to subsequent remodeling of the chromatin template during transcription. However, the interconnected network of molecules involved in regulating such processes remains elusive. hPaf1/PD2, a subunit of the human PAF-complex, involved in the regulation of transcriptional elongation has oncogenic potential. Our study explores the possibility that regulation of histone methylation by hPaf1 can contribute towards alteration in gene expression by nucleosomal rearrangement. Here, we show that knockdown of hPaf1/PD2 leads to decreased di- and tri-methylation at histone H3 lysine 4 residues in pancreatic cancer cells. Interestingly, hPaf1/PD2 colocalizes with MLL1 (Mixed Lineage Leukemia 1), a histone methyltransferase that methylates H3K4 residues. Also, a reduction in hPaf1 level resulted in reduced MLL1 expression and a corresponding decrease in the level of CHD1 (Chromohelicase DNA-binding protein 1), an ATPase dependent chromatin remodeling enzyme that specifically binds to H3K4 di and trimethyl marks. hPaf1/PD2 was also found to interact and colocalize with CHD1 in both cytoplasmic and nuclear extracts of pancreatic cancer cells. Further, reduced level of CHD1 localization in the nucleus in hPaf1/PD2 Knockdown cells could be rescued by ectopic expression of hPaf1/PD2. Micrococcal nuclease digestion showed an altered chromatin structure in hPaf1/PD2-KD cells. Overall, our results suggest that hPaf1/PD2 in association with MLL1 regulates methylation of H3K4 residues, as well as interacts and regulates nuclear shuttling of chromatin remodeling protein CHD1, facilitating its function in pancreatic cancer cells.
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Affiliation(s)
- Parama Dey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Moorthy P. Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shonali Deb
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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15
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Stevens JR, O'Donnell AF, Perry TE, Benjamin JJR, Barnes CA, Johnston GC, Singer RA. FACT, the Bur kinase pathway, and the histone co-repressor HirC have overlapping nucleosome-related roles in yeast transcription elongation. PLoS One 2011; 6:e25644. [PMID: 22022426 PMCID: PMC3192111 DOI: 10.1371/journal.pone.0025644] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/06/2011] [Indexed: 02/03/2023] Open
Abstract
Gene transcription is constrained by the nucleosomal nature of chromosomal DNA. This nucleosomal barrier is modulated by FACT, a conserved histone-binding heterodimer. FACT mediates transcription-linked nucleosome disassembly and also nucleosome reassembly in the wake of the RNA polymerase II transcription complex, and in this way maintains the repression of ‘cryptic’ promoters found within some genes. Here we focus on a novel mutant version of the yeast FACT subunit Spt16 that supplies essential Spt16 activities but impairs transcription-linked nucleosome reassembly in dominant fashion. This Spt16 mutant protein also has genetic effects that are recessive, which we used to show that certain Spt16 activities collaborate with histone acetylation and the activities of a Bur-kinase/Spt4–Spt5/Paf1C pathway that facilitate transcription elongation. These collaborating activities were opposed by the actions of Rpd3S, a histone deacetylase that restores a repressive chromatin environment in a transcription-linked manner. Spt16 activity paralleling that of HirC, a co-repressor of histone gene expression, was also found to be opposed by Rpd3S. Our findings suggest that Spt16, the Bur/Spt4–Spt5/Paf1C pathway, and normal histone abundance and/or stoichiometry, in mutually cooperative fashion, facilitate nucleosome disassembly during transcription elongation. The recessive nature of these effects of the mutant Spt16 protein on transcription-linked nucleosome disassembly, contrasted to its dominant negative effect on transcription-linked nucleosome reassembly, indicate that mutant FACT harbouring the mutant Spt16 protein competes poorly with normal FACT at the stage of transcription-linked nucleosome disassembly, but effectively with normal FACT for transcription-linked nucleosome reassembly. This functional difference is consistent with the idea that FACT association with the transcription elongation complex depends on nucleosome disassembly, and that the same FACT molecule that associates with an elongation complex through nucleosome disassembly is retained for reassembly of the same nucleosome.
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Affiliation(s)
- Jennifer R. Stevens
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Allyson F. O'Donnell
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Troy E. Perry
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jeremy J. R. Benjamin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christine A. Barnes
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Gerald C. Johnston
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Richard A. Singer
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
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The Paf1 complex represses SER3 transcription in Saccharomyces cerevisiae by facilitating intergenic transcription-dependent nucleosome occupancy of the SER3 promoter. EUKARYOTIC CELL 2011; 10:1283-94. [PMID: 21873510 DOI: 10.1128/ec.05141-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Previous studies have shown that repression of the Saccharomyces cerevisiae SER3 gene is dependent on transcription of SRG1 from noncoding DNA initiating within the intergenic region 5' of SER3 and extending across the SER3 promoter region. By a mechanism dependent on the activities of the Swi/Snf chromatin remodeling factor, the HMG-like factor Spt2, and the Spt6 and Spt16 histone chaperones, SRG1 transcription deposits nucleosomes over the SER3 promoter to prevent transcription factors from binding and activating SER3. In this study, we uncover a role for the Paf1 transcription elongation complex in SER3 repression. We find that SER3 repression is primarily dependent on the Paf1 and Ctr9 subunits of this complex, with minor contributions by the Rtf1, Cdc73, and Leo1 subunits. We show that the Paf1 complex localizes to the SRG1 transcribed region under conditions that repress SER3, consistent with it having a direct role in mediating SRG1 transcription-dependent SER3 repression. Importantly, we show that the defect in SER3 repression in strains lacking Paf1 subunits is not a result of reduced SRG1 transcription or reduced levels of known Paf1 complex-dependent histone modifications. Rather, we find that strains lacking subunits of the Paf1 complex exhibit reduced nucleosome occupancy and reduced recruitment of Spt16 and, to a lesser extent, Spt6 at the SER3 promoter. Taken together, our results suggest that Paf1 and Ctr9 repress SER3 by maintaining SRG1 transcription-dependent nucleosome occupancy.
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Buske FA, Mattick JS, Bailey TL. Potential in vivo roles of nucleic acid triple-helices. RNA Biol 2011; 8:427-39. [PMID: 21525785 DOI: 10.4161/rna.8.3.14999] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ability of double-stranded DNA to form a triple-helical structure by hydrogen bonding with a third strand is well established, but the biological functions of these structures remain largely unknown. There is considerable albeit circumstantial evidence for the existence of nucleic triplexes in vivo and their potential participation in a variety of biological processes including chromatin organization, DNA repair, transcriptional regulation, and RNA processing has been investigated in a number of studies to date. There is also a range of possible mechanisms to regulate triplex formation through differential expression of triplex-forming RNAs, alteration of chromatin accessibility, sequence unwinding and nucleotide modifications. With the advent of next generation sequencing technology combined with targeted approaches to isolate triplexes, it is now possible to survey triplex formation with respect to their genomic context, abundance and dynamical changes during differentiation and development, which may open up new vistas in understanding genome biology and gene regulation.
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Affiliation(s)
- Fabian A Buske
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD Australia
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Dermody JL, Buratowski S. Leo1 subunit of the yeast paf1 complex binds RNA and contributes to complex recruitment. J Biol Chem 2010; 285:33671-9. [PMID: 20732871 DOI: 10.1074/jbc.m110.140764] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The Paf1 complex (Paf1C) affects RNA polymerase II transcription by coordinating co-transcriptional chromatin modifications and helping recruit mRNA 3' end processing factors. Paf1C cross-links to transcribed genes, but not downstream of the cleavage and polyadenylation site, suggesting that it may interact with the nascent mRNA. Paf1C purified from Saccharomyces cerevisiae binds RNA in vitro, as do the purified Leo1 and Rtf1 subunits of the complex. In vivo cross-linking and immunoprecipitation of RNA associated with Paf1C (RNA-IP) show that Leo1, but not Rtf1, is necessary for the complex to bind RNA. Cells lacking Leo1 have reduced Paf1C recruitment as well as decreased levels of histone H3 and trimethylated H3 Lys(4) within transcribed chromatin. Together, these results suggest that association of Paf1C with RNA stabilizes its localization at actively transcribed regions where it influences chromatin structure.
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Affiliation(s)
- Jessica L Dermody
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Hontz RD, Niederer RO, Johnson JM, Smith JS. Genetic identification of factors that modulate ribosomal DNA transcription in Saccharomyces cerevisiae. Genetics 2009; 182:105-19. [PMID: 19270272 PMCID: PMC2674809 DOI: 10.1534/genetics.108.100313] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 02/27/2009] [Indexed: 11/18/2022] Open
Abstract
Ribosomal RNA (rRNA) is transcribed from the ribosomal DNA (rDNA) genes by RNA polymerase I (Pol I). Despite being responsible for the majority of transcription in growing cells, Pol I regulation is poorly understood compared to Pol II. To gain new insights into rDNA transcriptional regulation, we developed a genetic assay in Saccharomyces cerevisiae that detects alterations in transcription from the centromere-proximal rDNA gene of the tandem array. Changes in Pol I transcription at this gene alter the expression of an adjacent, modified URA3 reporter cassette (mURA3) such that reductions in Pol I transcription induce growth on synthetic media lacking uracil. Increases in Pol I transcription induce growth on media containing 5-FOA. A transposon mutagenesis screen was performed with the reporter strain to identify genes that play a role in modulating rDNA transcription. Mutations in 68 different genes were identified, several of which were already known to function in chromatin modification and the regulation of Pol II transcription. Among the other classes of genes were those encoding proteasome subunits and multiple kinases and phosphatases that function in nutrient and stress signaling pathways. Fourteen genes were previously uncharacterized and have been named as regulators of rDNA transcription (RRT).
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Affiliation(s)
- Robert D Hontz
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, Virginia 22908, USA
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