1
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Patil S, Cremosnik G, Dötsch L, Flegel J, Schulte B, Maier KC, Žumer K, Cramer P, Janning P, Sievers S, Ziegler S, Waldmann H. The Pseudo-Natural Product Tafbromin Selectively Targets the TAF1 Bromodomain 2. Angew Chem Int Ed Engl 2024; 63:e202404645. [PMID: 38801173 DOI: 10.1002/anie.202404645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/17/2024] [Accepted: 05/23/2024] [Indexed: 05/29/2024]
Abstract
Phenotypic assays detect small-molecule bioactivity at functionally relevant cellular sites, and inherently cover a variety of targets and mechanisms of action. They can uncover new small molecule-target pairs and may give rise to novel biological insights. By means of an osteoblast differentiation assay which employs a Hedgehog (Hh) signaling agonist as stimulus and which monitors an endogenous marker for osteoblasts, we identified a pyrrolo[3,4-g]quinoline (PQ) pseudo-natural product (PNP) class of osteogenesis inhibitors. The most potent PQ, termed Tafbromin, impairs canonical Hh signaling and modulates osteoblast differentiation through binding to the bromodomain 2 of the TATA-box binding protein-associated factor 1 (TAF1). Tafbromin is the most selective TAF1 bromodomain 2 ligand and promises to be an invaluable tool for the study of biological processes mediated by TAF1(2) bromodomains.
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Affiliation(s)
- Sohan Patil
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Gregor Cremosnik
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Lara Dötsch
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
- Technical University Dortmund, Faculty of Chemistry and Chemical Biology, Otto-Hahn-Strasse 6, Dortmund, 44227, Germany
| | - Jana Flegel
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Britta Schulte
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Kerstin C Maier
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Kristina Žumer
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Petra Janning
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Sonja Sievers
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Slava Ziegler
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
| | - Herbert Waldmann
- Max-Planck Institute of Molecular Physiology, Department of Chemical Biology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany
- Technical University Dortmund, Faculty of Chemistry and Chemical Biology, Otto-Hahn-Strasse 6, Dortmund, 44227, Germany
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2
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Li T, Chao TC, Tsai KL. Structures and compositional dynamics of Mediator in transcription regulation. Curr Opin Struct Biol 2024; 88:102892. [PMID: 39067114 DOI: 10.1016/j.sbi.2024.102892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/30/2024] [Accepted: 07/05/2024] [Indexed: 07/30/2024]
Abstract
The eukaryotic Mediator, comprising a large Core (cMED) and a dissociable CDK8 kinase module (CKM), functions as a critical coregulator during RNA polymerase II (RNAPII) transcription. cMED recruits RNAPII and facilitates the assembly of the pre-initiation complex (PIC) at promoters. In contrast, CKM prevents RNAPII binding to cMED while simultaneously exerting positive or negative influence on gene transcription through its kinase function. Recent structural studies on cMED and CKM have revealed their intricate architectures and subunit interactions. Here, we explore these structures, providing a comprehensive insight into Mediator (cMED-CKM) architecture and its potential mechanism in regulating RNAPII transcription. Additionally, we discuss the remaining puzzles that require further investigation to fully understand how cMED coordinates with CKM to regulate transcription in various events.
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Affiliation(s)
- Tao Li
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston TX, USA
| | - Ti-Chun Chao
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston TX, USA
| | - Kuang-Lei Tsai
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston TX, USA.
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3
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Chen SF, Chao TC, Kim HJ, Tang HC, Khadka S, Li T, Lee DF, Murakami K, Boyer TG, Tsai KL. Structural basis of the human transcriptional Mediator complex modulated by its dissociable Kinase module. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.01.601608. [PMID: 39005267 PMCID: PMC11244988 DOI: 10.1101/2024.07.01.601608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
The eukaryotic Mediator, comprising a large Core (cMED) and a dissociable CDK8 kinase module (CKM), regulates RNA Polymerase II (Pol II)-dependent transcription. cMED recruits Pol II and promotes pre-initiation complex (PIC) formation in a manner inhibited by the CKM, which is also implicated in post-initiation control of gene expression. Herein we report cryo-electron microscopy structures of the human complete Mediator and its CKM, which explains the basis for CKM inhibition of cMED-activated transcription. The CKM binds to cMED through an intrinsically disordered region (IDR) in MED13 and HEAT repeats in MED12. The CKM inhibits transcription by allocating its MED13 IDR to occlude binding of Pol II and MED26 to cMED and further obstructing cMED-PIC assembly through steric hindrance with TFIIH and the +1 nucleosome. Notably, MED12 binds to the cMED Hook, positioning CDK8 downstream of the transcription start site, which sheds new light on its stimulatory function in post-initiation events.
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4
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Struhl K. Non-canonical functions of enhancers: regulation of RNA polymerase III transcription, DNA replication, and V(D)J recombination. Trends Genet 2024; 40:471-479. [PMID: 38643034 PMCID: PMC11152991 DOI: 10.1016/j.tig.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/02/2024] [Indexed: 04/22/2024]
Abstract
Enhancers are the key regulators of other DNA-based processes by virtue of their unique ability to generate nucleosome-depleted regions in a highly regulated manner. Enhancers regulate cell-type-specific transcription of tRNA genes by RNA polymerase III (Pol III). They are also responsible for the binding of the origin replication complex (ORC) to DNA replication origins, thereby regulating origin utilization, replication timing, and replication-dependent chromosome breaks. Additionally, enhancers regulate V(D)J recombination by increasing access of the recombination-activating gene (RAG) recombinase to target sites and by generating non-coding enhancer RNAs and localized regions of trimethylated histone H3-K4 recognized by the RAG2 PHD domain. Thus, enhancers represent the first step in decoding the genome, and hence they regulate biological processes that, unlike RNA polymerase II (Pol II) transcription, do not have dedicated regulatory proteins.
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Affiliation(s)
- Kevin Struhl
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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5
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Bell CC, Balic JJ, Talarmain L, Gillespie A, Scolamiero L, Lam EYN, Ang CS, Faulkner GJ, Gilan O, Dawson MA. Comparative cofactor screens show the influence of transactivation domains and core promoters on the mechanisms of transcription. Nat Genet 2024; 56:1181-1192. [PMID: 38769457 DOI: 10.1038/s41588-024-01749-z] [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: 11/30/2023] [Accepted: 04/09/2024] [Indexed: 05/22/2024]
Abstract
Eukaryotic transcription factors (TFs) activate gene expression by recruiting cofactors to promoters. However, the relationships between TFs, promoters and their associated cofactors remain poorly understood. Here we combine GAL4-transactivation assays with comparative CRISPR-Cas9 screens to identify the cofactors used by nine different TFs and core promoters in human cells. Using this dataset, we associate TFs with cofactors, classify cofactors as ubiquitous or specific and discover transcriptional co-dependencies. Through a reductionistic, comparative approach, we demonstrate that TFs do not display discrete mechanisms of activation. Instead, each TF depends on a unique combination of cofactors, which influences distinct steps in transcription. By contrast, the influence of core promoters appears relatively discrete. Different promoter classes are constrained by either initiation or pause-release, which influences their dynamic range and compatibility with cofactors. Overall, our comparative cofactor screens characterize the interplay between TFs, cofactors and core promoters, identifying general principles by which they influence transcription.
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Affiliation(s)
- Charles C Bell
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, Queensland, Australia.
| | - Jesse J Balic
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Laure Talarmain
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrea Gillespie
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Laura Scolamiero
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Enid Y N Lam
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Ching-Seng Ang
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, Queensland, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Omer Gilan
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Mark A Dawson
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
- Department of Haematology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
- Centre for Cancer Research, University of Melbourne, Melbourne, Victoria, Australia.
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6
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Bunch H, Kim D, Naganuma M, Nakagawa R, Cong A, Jeong J, Ehara H, Vu H, Chang JH, Schellenberg MJ, Sekine SI. ERK2-topoisomerase II regulatory axis is important for gene activation in immediate early genes. Nat Commun 2023; 14:8341. [PMID: 38097570 PMCID: PMC10721843 DOI: 10.1038/s41467-023-44089-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/29/2023] [Indexed: 12/17/2023] Open
Abstract
The function of the mitogen-activated protein kinase signaling pathway is required for the activation of immediate early genes (IEGs), including EGR1 and FOS, for cell growth and proliferation. Recent studies have identified topoisomerase II (TOP2) as one of the important regulators of the transcriptional activation of IEGs. However, the mechanism underlying transcriptional regulation involving TOP2 in IEG activation has remained unknown. Here, we demonstrate that ERK2, but not ERK1, is important for IEG transcriptional activation and report a critical ELK1 binding sequence for ERK2 function at the EGR1 gene. Our data indicate that both ERK1 and ERK2 extensively phosphorylate the C-terminal domain of TOP2B at mutual and distinctive residues. Although both ERK1 and ERK2 enhance the catalytic rate of TOP2B required to relax positive DNA supercoiling, ERK2 delays TOP2B catalysis of negative DNA supercoiling. In addition, ERK1 may relax DNA supercoiling by itself. ERK2 catalytic inhibition or knock-down interferes with transcription and deregulates TOP2B in IEGs. Furthermore, we present the first cryo-EM structure of the human cell-purified TOP2B and etoposide together with the EGR1 transcriptional start site (-30 to +20) that has the strongest affinity to TOP2B within -423 to +332. The structure shows TOP2B-mediated breakage and dramatic bending of the DNA. Transcription is activated by etoposide, while it is inhibited by ICRF193 at EGR1 and FOS, suggesting that TOP2B-mediated DNA break to favor transcriptional activation. Taken together, this study suggests that activated ERK2 phosphorylates TOP2B to regulate TOP2-DNA interactions and favor transcriptional activation in IEGs. We propose that TOP2B association, catalysis, and dissociation on its substrate DNA are important processes for regulating transcription and that ERK2-mediated TOP2B phosphorylation may be key for the catalysis and dissociation steps.
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Affiliation(s)
- Heeyoun Bunch
- Department of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
- School of Applied Biosciences, College of Agriculture & Life Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
| | - Deukyeong Kim
- School of Applied Biosciences, College of Agriculture & Life Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Masahiro Naganuma
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Reiko Nakagawa
- RIKEN BDR Laboratory for Phyloinformatics, Hyogo, 650-0047, Japan
| | - Anh Cong
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jaehyeon Jeong
- Department of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Hongha Vu
- Department of Biology Education, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Jeong Ho Chang
- Department of Biology Education, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Matthew J Schellenberg
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Shun-Ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
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7
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Duran E, Schmidt A, Welty R, Jalihal AP, Pitchiaya S, Walter NG. Utilizing functional cell-free extracts to dissect ribonucleoprotein complex biology at single-molecule resolution. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1787. [PMID: 37042458 PMCID: PMC10524090 DOI: 10.1002/wrna.1787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Cellular machineries that drive and regulate gene expression often rely on the coordinated assembly and interaction of a multitude of proteins and RNA together called ribonucleoprotein complexes (RNPs). As such, it is challenging to fully reconstitute these cellular machines recombinantly and gain mechanistic understanding of how they operate and are regulated within the complex environment that is the cell. One strategy for overcoming this challenge is to perform single molecule fluorescence microscopy studies within crude or recombinantly supplemented cell extracts. This strategy enables elucidation of the interaction and kinetic behavior of specific fluorescently labeled biomolecules within RNPs under conditions that approximate native cellular environments. In this review, we describe single molecule fluorescence microcopy approaches that dissect RNP-driven processes within cellular extracts, highlighting general strategies used in these methods. We further survey biological advances in the areas of pre-mRNA splicing and transcription regulation that have been facilitated through this approach. Finally, we conclude with a summary of practical considerations for the implementation of the featured approaches to facilitate their broader future implementation in dissecting the mechanisms of RNP-driven cellular processes. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Elizabeth Duran
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Andreas Schmidt
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Robb Welty
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Ameya P Jalihal
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Sethuramasundaram Pitchiaya
- Michigan Center for Translational Pathology, Department of Pathology, Department of Urology, Michigan Medicine, Ann Arbor, Michigan, USA
| | - Nils G Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
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8
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Suzuki H, Furugori K, Abe R, Ogawa S, Ito S, Akiyama T, Horiuchi K, Takahashi H. MED26-containing Mediator may orchestrate multiple transcription processes through organization of nuclear bodies. Bioessays 2023; 45:e2200178. [PMID: 36852638 DOI: 10.1002/bies.202200178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 03/01/2023]
Abstract
Mediator is a coregulatory complex that plays essential roles in multiple processes of transcription regulation. One of the human Mediator subunits, MED26, has a role in recruitment of the super elongation complex (SEC) to polyadenylated genes and little elongation complex (LEC) to non-polyadenylated genes, including small nuclear RNAs (snRNAs) and replication-dependent histone (RDH) genes. MED26-containing Mediator plays a role in 3' Pol II pausing at the proximal region of transcript end sites in RDH genes through recruitment of Cajal bodies (CBs) to histone locus bodies (HLBs). This finding suggests that Mediator is involved in the association of CBs with HLBs to facilitate 3' Pol II pausing and subsequent 3'-end processing by supplying 3'-end processing factors from CBs. Thus, we argue the possibility that Mediator is involved in the organization of nuclear bodies to orchestrate multiple processes of gene transcription.
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Affiliation(s)
- Hidefumi Suzuki
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Kazuki Furugori
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Ryota Abe
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Shintaro Ogawa
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Sayaka Ito
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Tomohiko Akiyama
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Keiko Horiuchi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
| | - Hidehisa Takahashi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Yokohama, Kanagawa, Japan
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9
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Collin A, González-Jiménez A, González-Jiménez MDC, Alfonso MJ, Calvo O. The Role of S. cerevisiae Sub1/PC4 in Transcription Elongation Depends on the C-Terminal Region and Is Independent of the ssDNA Binding Domain. Cells 2022; 11:cells11203320. [PMID: 36291192 PMCID: PMC9600219 DOI: 10.3390/cells11203320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/30/2022] Open
Abstract
Saccharomyces cerevisiae Sub1 (ScSub1) has been defined as a transcriptional stimulatory protein due to its homology to the ssDNA binding domain (ssDBD) of human PC4 (hPC4). Recently, PC4/Sub1 orthologues have been elucidated in eukaryotes, prokaryotes, and bacteriophages with functions related to DNA metabolism. Additionally, ScSub1 contains a unique carboxyl–terminal region (CT) of unknown function up to date. Specifically, it has been shown that Sub1 is required for transcription activation, as well as other processes, throughout the transcription cycle. Despite the progress that has been made in understanding the mechanism underlying Sub1′s functions, some questions remain unanswered. As a case in point: whether Sub1’s roles in initiation and elongation are differentially predicated on distinct regions of the protein or how Sub1′s functions are regulated. Here, we uncover some residues that are key for DNA–ScSub1 interaction in vivo, localized in the ssDBD, and required for Sub1 recruitment to promoters. Furthermore, using an array of genetic and molecular techniques, we demonstrate that the CT region is required for transcription elongation by RNA polymerase II (RNAPII). Altogether, our data indicate that Sub1 plays a dual role during transcription—in initiation through the ssDBD and in elongation through the CT region.
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Affiliation(s)
- Alejandro Collin
- Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas-INICSA, CONICET-Universidad Nacional de Córdoba, Haya de la Torre s/n, Pabellón Argentina, 2º piso. Ciudad Universitaria, Cordoba CP5000, Argentina
| | - Araceli González-Jiménez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain
| | | | - Manuel J. Alfonso
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain
| | - Olga Calvo
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain
- Correspondence:
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10
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Rawson JMO, Nikolaitchik OA, Shakya S, Keele BF, Pathak VK, Hu WS. Transcription Start Site Heterogeneity and Preferential Packaging of Specific Full-Length RNA Species Are Conserved Features of Primate Lentiviruses. Microbiol Spectr 2022; 10:e0105322. [PMID: 35736240 PMCID: PMC9430795 DOI: 10.1128/spectrum.01053-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/05/2022] [Indexed: 11/22/2022] Open
Abstract
HIV-1 must package its RNA genome to generate infectious viruses. Recent studies have revealed that during genome packaging, HIV-1 not only excludes cellular mRNAs, but also distinguishes among full-length viral RNAs. Using NL4-3 and MAL molecular clones, multiple transcription start sites (TSS) were identified, which generate full-length RNAs that differ by only a few nucleotides at the 5' end. However, HIV-1 selectively packages RNAs containing one guanosine (1G RNA) over RNAs with three guanosines (3G RNA) at the 5' end. Thus, the 5' context of HIV-1 full-length RNA can affect its function. To determine whether the regulation of genome packaging by TSS usage is unique to NL4-3 and MAL, we examined 15 primate lentiviruses including transmitted founder viruses of HIV-1, HIV-2, and several simian immunodeficiency viruses (SIVs). We found that all 15 viruses used multiple TSS to some extent. However, the level of TSS heterogeneity in infected cells varied greatly, even among closely related viruses belonging to the same subtype. Most viruses also exhibited selective packaging of specific full-length viral RNA species into particles. These findings demonstrate that TSS heterogeneity and selective packaging of certain full-length viral RNA species are conserved features of primate lentiviruses. In addition, an SIV strain closely related to the progenitor virus that gave rise to HIV-1 group M, the pandemic pathogen, exhibited TSS usage similar to some HIV-1 strains and preferentially packaged 1G RNA. These findings indicate that multiple TSS usage and selective packaging of a particular unspliced RNA species predate the emergence of HIV-1. IMPORTANCE Unspliced HIV-1 RNA serves two important roles during viral replication: as the virion genome and as the template for translation of Gag/Gag-Pol. Previous studies of two HIV-1 molecular clones have concluded that the TSS usage affects unspliced HIV-1 RNA structures and functions. To investigate the evolutionary origin of this replication strategy, we determined TSS of HIV-1 RNA in infected cells and virions for 15 primate lentiviruses. All HIV-1 isolates examined, including several transmitted founder viruses, utilized multiple TSS and selected a particular RNA species for packaging. Furthermore, these features were observed in SIVs related to the progenitors of HIV-1, suggesting that these characteristics originated from the ancestral viruses. HIV-2, SIVs related to HIV-2, and other SIVs also exhibited multiple TSS and preferential packaging of specific unspliced RNA species, demonstrating that this replication strategy is broadly conserved across primate lentiviruses.
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Affiliation(s)
- Jonathan M. O. Rawson
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Olga A. Nikolaitchik
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Saurabh Shakya
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Brandon F. Keele
- AIDS and Cancer Virus Program, Frederick National Laboratory, Frederick, Maryland, USA
| | - Vinay K. Pathak
- Viral Mutation Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
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11
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Santana JF, Collins GS, Parida M, Luse DS, Price D. Differential dependencies of human RNA polymerase II promoters on TBP, TAF1, TFIIB and XPB. Nucleic Acids Res 2022; 50:9127-9148. [PMID: 35947745 PMCID: PMC9458433 DOI: 10.1093/nar/gkac678] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/08/2022] [Accepted: 07/27/2022] [Indexed: 12/24/2022] Open
Abstract
The effects of rapid acute depletion of components of RNA polymerase II (Pol II) general transcription factors (GTFs) that are thought to be critical for formation of preinitiation complexes (PICs) and initiation in vitro were quantified in HAP1 cells using precision nuclear run-on sequencing (PRO-Seq). The average dependencies for each factor across >70 000 promoters varied widely even though levels of depletions were similar. Some of the effects could be attributed to the presence or absence of core promoter elements such as the upstream TBP-specificity motif or downstream G-rich sequences, but some dependencies anti-correlated with such sequences. While depletion of TBP had a large effect on most Pol III promoters only a small fraction of Pol II promoters were similarly affected. TFIIB depletion had the largest general effect on Pol II and also correlated with apparent termination defects downstream of genes. Our results demonstrate that promoter activity is combinatorially influenced by recruitment of TFIID and sequence-specific transcription factors. They also suggest that interaction of the preinitiation complex (PIC) with nucleosomes can affect activity and that recruitment of TFIID containing TBP only plays a positive role at a subset of promoters.
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Affiliation(s)
- Juan F Santana
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Geoffrey S Collins
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Mrutyunjaya Parida
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Donal S Luse
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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12
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Morse RH. Function and dynamics of the Mediator complex: novel insights and new frontiers. Transcription 2022; 13:39-52. [PMID: 35708525 PMCID: PMC9467533 DOI: 10.1080/21541264.2022.2085502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The Mediator complex was discovered in the early 1990s as a biochemically fractionated factor from yeast extracts that was necessary for activator-stimulated transcriptional activation to be observed in in vitro transcription assays. The structure of this large, multi-protein complex is now understood in great detail, and novel genetic approaches have provided rich insights into its dynamics during transcriptional activation and the mechanism by which it facilitates activated transcription. Here I review recent findings and unanswered questions regarding Mediator dynamics, the roles of individual subunits, and differences between its function in yeast and metazoan cells.
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Affiliation(s)
- Randall H Morse
- Wadsworth Center, New York State Department of Health, Albany, NY, United States.,Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY, United States
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13
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Morgan M, Shiekhattar R, Shilatifard A, Lauberth SM. It's a DoG-eat-DoG world-altered transcriptional mechanisms drive downstream-of-gene (DoG) transcript production. Mol Cell 2022; 82:1981-1991. [PMID: 35487209 PMCID: PMC9208299 DOI: 10.1016/j.molcel.2022.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/24/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
The past decade has revolutionized our understanding of regulatory noncoding RNAs (ncRNAs). Among the most recently identified ncRNAs are downstream-of-gene (DoG)-containing transcripts that are produced by widespread transcriptional readthrough. The discovery of DoGs has set the stage for future studies to address many unanswered questions regarding the mechanisms that promote readthrough transcription, RNA processing, and the cellular functions of the unique transcripts. In this review, we summarize current findings regarding the biogenesis, function, and mechanisms regulating this exciting new class of RNA molecules.
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Affiliation(s)
- Marc Morgan
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ramin Shiekhattar
- Department of Human Genetics, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Shannon M Lauberth
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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