1
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Kiliti AJ, Sharif GM, Martin MB, Wellstein A, Riegel AT. AIB1/SRC-3/NCOA3 function in estrogen receptor alpha positive breast cancer. Front Endocrinol (Lausanne) 2023; 14:1250218. [PMID: 37711895 PMCID: PMC10498919 DOI: 10.3389/fendo.2023.1250218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/14/2023] [Indexed: 09/16/2023] Open
Abstract
The estrogen receptor alpha (ERα) is a steroid receptor that is pivotal in the initiation and progression of most breast cancers. ERα regulates gene transcription through recruitment of essential coregulators, including the steroid receptor coactivator AIB1 (Amplified in Breast Cancer 1). AIB1 itself is an oncogene that is overexpressed in a subset of breast cancers and is known to play a role in tumor progression and resistance to endocrine therapy through multiple mechanisms. Here we review the normal and pathological functions of AIB1 in regard to its ERα-dependent and ERα-independent actions, as well as its genomic conservation and protein evolution. We also outline the efforts to target AIB1 in the treatment of breast cancer.
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Affiliation(s)
- Amber J. Kiliti
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
- Department of Biochemistry, Molecular and Cellular Biology, Georgetown University, Washington, DC, United States
| | - Ghada M. Sharif
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Mary Beth Martin
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
- Department of Biochemistry, Molecular and Cellular Biology, Georgetown University, Washington, DC, United States
| | - Anton Wellstein
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Anna T. Riegel
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
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2
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Compe E, Egly JM. The Long Road to Understanding RNAPII Transcription Initiation and Related Syndromes. Annu Rev Biochem 2021; 90:193-219. [PMID: 34153211 DOI: 10.1146/annurev-biochem-090220-112253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In eukaryotes, transcription of protein-coding genes requires the assembly at core promoters of a large preinitiation machinery containing RNA polymerase II (RNAPII) and general transcription factors (GTFs). Transcription is potentiated by regulatory elements called enhancers, which are recognized by specific DNA-binding transcription factors that recruit cofactors and convey, following chromatin remodeling, the activating cues to the preinitiation complex. This review summarizes nearly five decades of work on transcription initiation by describing the sequential recruitment of diverse molecular players including the GTFs, the Mediator complex, and DNA repair factors that support RNAPII to enable RNA synthesis. The elucidation of the transcription initiation mechanism has greatly benefited from the study of altered transcription components associated with human diseases that could be considered transcription syndromes.
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Affiliation(s)
- Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch CEDEX, Commune Urbaine de Strasbourg, France; ,
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch CEDEX, Commune Urbaine de Strasbourg, France; , .,College of Medicine, National Taiwan University, Taipei 10051, Taiwan
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3
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Wang H, Xing J, Wang W, Lv G, He H, Lu Y, Sun M, Chen H, Li X. Molecular Characterization of the Oncogene BTF3 and Its Targets in Colorectal Cancer. Front Cell Dev Biol 2021; 8:601502. [PMID: 33644029 PMCID: PMC7905040 DOI: 10.3389/fcell.2020.601502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/26/2020] [Indexed: 01/12/2023] Open
Abstract
Colorectal cancer (CRC) is one of the most commonly diagnosed and leading causes of cancer mortality worldwide, and the prognosis of patients with CRC remains unsatisfactory. Basic transcription factor 3 (BTF3) is an oncogene and hazardous prognosticator in CRC. Although two distinct functional mechanisms of BTF3 in different cancer types have been reported, its role in CRC is still unclear. In this study, we aimed to molecularly characterize the oncogene BTF3 and its targets in CRC. Here, we first identified the transcriptional targets of BTF3 by applying combined RNA-Seq and ChIP-Seq analysis, identifying CHD1L as a transcriptional target of BTF3. Thereafter, we conducted immunoprecipitation (IP)-MS and E3 ubiquitin ligase analysis to identify potential interacting targets of BTF3 as a subunit of the nascent-polypeptide-associated complex (NAC). The analysis revealed that BTF3 might also inhibit E3 ubiquitin ligase HERC2-mediated p53 degradation. Finally, miRNAs targeting BTF3 were predicted and validated. Decreased miR-497-5p expression is responsible for higher levels of BTF3 post-transcriptionally. Collectively, we concluded that BTF3 is an oncogene, and there may exist a transcription factor and NAC-related proteolysis mechanism in CRC. This study provides a comprehensive basis for understanding the oncogenic mechanisms of BTF3 in CRC.
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Affiliation(s)
- Hantao Wang
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, China
| | - Junjie Xing
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, China
| | - Wei Wang
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, China
| | - Guifen Lv
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, China
| | - Haiyan He
- Department of Digestive Endoscopy, Changhai Hospital, Shanghai, China
| | - Yeqing Lu
- Department of Anesthesiology, Changhai Hospital, Shanghai, China
| | - Mei Sun
- Department of Anesthesiology, Changhai Hospital, Shanghai, China
| | - Haiyan Chen
- Department of Endocrinology, Changzheng Hospital, Shanghai, China
| | - Xu Li
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, China
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4
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Timmers HTM. SAGA and TFIID: Friends of TBP drifting apart. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194604. [PMID: 32673655 DOI: 10.1016/j.bbagrm.2020.194604] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 01/24/2023]
Abstract
Transcription initiation constitutes a major checkpoint in gene regulation across all living organisms. Control of chromatin function is tightly linked to this checkpoint, which is best illustrated by the SAGA coactivator. This evolutionary conserved complex of 18-20 subunits was first discovered as a Gcn5p-containing histone acetyltransferase, but it also integrates a histone H2B deubiquitinase. The SAGA subunits are organized in a modular fashion around its central core. Strikingly, this central module of SAGA shares a number of proteins with the central core of the basal transcription factor TFIID. In this review I will compare the SAGA and TFIID complexes with respect to their shared subunits, structural organization, enzymatic activities and chromatin binding. I will place a special emphasis on the ancestry of SAGA and TFIID subunits, which suggests that these complexes evolved to control the activity of TBP (TATA-binding protein) in directing the assembly of transcription initiation complexes.
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Affiliation(s)
- H Th Marc Timmers
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; German Cancer Consortium (DKTK) partner site Freiburg, 79106 Freiburg, Germany; Department of Urology, Medical Center-University of Freiburg, Breisacher Straße 66, 79106 Freiburg, Germany.
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5
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Kramm K, Schröder T, Gouge J, Vera AM, Gupta K, Heiss FB, Liedl T, Engel C, Berger I, Vannini A, Tinnefeld P, Grohmann D. DNA origami-based single-molecule force spectroscopy elucidates RNA Polymerase III pre-initiation complex stability. Nat Commun 2020; 11:2828. [PMID: 32504003 PMCID: PMC7275037 DOI: 10.1038/s41467-020-16702-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 05/13/2020] [Indexed: 01/03/2023] Open
Abstract
The TATA-binding protein (TBP) and a transcription factor (TF) IIB-like factor are important constituents of all eukaryotic initiation complexes. The reason for the emergence and strict requirement of the additional initiation factor Bdp1 in the RNA polymerase (RNAP) III system, however, remained elusive. A poorly studied aspect in this context is the effect of DNA strain arising from DNA compaction and transcriptional activity on initiation complex formation. We made use of a DNA origami-based force clamp to follow the assembly of human initiation complexes in the RNAP II and RNAP III systems at the single-molecule level under piconewton forces. We demonstrate that TBP-DNA complexes are force-sensitive and TFIIB is sufficient to stabilise TBP on a strained promoter. In contrast, Bdp1 is the pivotal component that ensures stable anchoring of initiation factors, and thus the polymerase itself, in the RNAP III system. Thereby, we offer an explanation for the crucial role of Bdp1 for the high transcriptional output of RNAP III.
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Affiliation(s)
- Kevin Kramm
- Single-Molecule Biochemistry Lab, Institute of Microbiology and Archaea Centre, University of Regensburg, 93053, Regensburg, Germany
| | - Tim Schröder
- Department of Chemistry and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539, München, Germany
| | - Jerome Gouge
- Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK
| | - Andrés Manuel Vera
- Department of Chemistry and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539, München, Germany
| | - Kapil Gupta
- Bristol Synthetic Biology Centre BrisSynBio, Biomedical Sciences, University of Bristol, 1 Tankard's Close, Clifton, BS8 1TD, UK
| | - Florian B Heiss
- Regensburg Center of Biochemistry (RCB), University of Regensburg, 93053, Regensburg, Germany
| | - Tim Liedl
- Faculty of Physics and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Christoph Engel
- Regensburg Center of Biochemistry (RCB), University of Regensburg, 93053, Regensburg, Germany
| | - Imre Berger
- Bristol Synthetic Biology Centre BrisSynBio, Biomedical Sciences, University of Bristol, 1 Tankard's Close, Clifton, BS8 1TD, UK
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK
- Human Technopole Foundation, Centre of Structural Biology, 20157, Milan, Italy
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539, München, Germany
| | - Dina Grohmann
- Single-Molecule Biochemistry Lab, Institute of Microbiology and Archaea Centre, University of Regensburg, 93053, Regensburg, Germany.
- Regensburg Center of Biochemistry (RCB), University of Regensburg, 93053, Regensburg, Germany.
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6
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Upregulation of BTF3 affects the proliferation, apoptosis, and cell cycle regulation in hypopharyngeal squamous cell carcinoma. Biomed Pharmacother 2019; 118:109211. [DOI: 10.1016/j.biopha.2019.109211] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/27/2019] [Accepted: 07/08/2019] [Indexed: 12/15/2022] Open
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7
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Roeder RG. 50+ years of eukaryotic transcription: an expanding universe of factors and mechanisms. Nat Struct Mol Biol 2019; 26:783-791. [PMID: 31439941 DOI: 10.1038/s41594-019-0287-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 07/26/2019] [Indexed: 12/12/2022]
Abstract
The landmark 1969 discovery of nuclear RNA polymerases I, II and III in diverse eukaryotes represented a major turning point in the field that, with subsequent elucidation of the distinct structures and functions of these enzymes, catalyzed an avalanche of further studies. In this Review, written from a personal and historical perspective, I highlight foundational biochemical studies that led to the discovery of an expanding universe of the components of the transcriptional and regulatory machineries, and a parallel complexity in gene-specific mechanisms that continue to be explored to the present day.
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Affiliation(s)
- Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, New York, USA.
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8
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Jackobel AJ, Zeberl BJ, Glover DM, Fakhouri AM, Knutson BA. DNA binding preferences of S. cerevisiae RNA polymerase I Core Factor reveal a preference for the GC-minor groove and a conserved binding mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194408. [PMID: 31382053 DOI: 10.1016/j.bbagrm.2019.194408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/03/2019] [Accepted: 07/23/2019] [Indexed: 01/24/2023]
Abstract
In Saccharomyces cerevisiae, Core Factor (CF) is a key evolutionarily conserved transcription initiation factor that helps recruit RNA polymerase I (Pol I) to the ribosomal DNA (rDNA) promoter. Upregulated Pol I transcription has been linked to many cancers, and targeting Pol I is an attractive and emerging anti-cancer strategy. Using yeast as a model system, we characterized how CF binds to the Pol I promoter by electrophoretic mobility shift assays (EMSA). Synthetic DNA competitors along with anti-tumor drugs and nucleic acid stains that act as DNA groove blockers were used to discover the binding preference of yeast CF. Our results show that CF employs a unique binding mechanism where it prefers the GC-rich minor groove within the rDNA promoter. In addition, we show that yeast CF is able to bind to the human rDNA promoter sequence that is divergent in DNA sequence and demonstrate CF sensitivity to the human specific Pol I inhibitor, CX-5461. Finally, we show that the human Core Promoter Element (CPE) can functionally replace the yeast Core Element (CE) in vivo when aligned by conserved DNA structural features rather than DNA sequence. Together, these findings suggest that the yeast CF and the human ortholog Selectivity Factor 1 (SL1) use an evolutionarily conserved, structure-based mechanism to target DNA. Their shared mechanism may offer a new avenue in using yeast to explore current and future Pol I anti-cancer compounds.
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Affiliation(s)
- Ashleigh J Jackobel
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Brian J Zeberl
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Danea M Glover
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; School of Graduate Studies, Rutgers Biomedical and Health Sciences, Rutgers University, Piscataway, NJ 08854, USA
| | - Aula M Fakhouri
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Bruce A Knutson
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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9
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Liu Q, Wu J, Lu T, Fang Z, Huang Z, Lu S, Dai C, Li M. Positive expression of basic transcription factor 3 predicts poor survival of colorectal cancer patients: possible mechanisms involved. Cell Death Dis 2019; 10:509. [PMID: 31263147 PMCID: PMC6603001 DOI: 10.1038/s41419-019-1747-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 02/06/2023]
Abstract
Basic transcription factor 3 (BTF3) is associated with the development of several cancers. The aim of our study was to elucidate the role of BTF3 in colorectal cancer (CRC) tissues. CRC tissues or their paired adjacent noncancerous (ANCT) tissues were obtained from 90 patients who underwent operations in our hospital from November 2011 to December 2016, and then we implemented a gene microarray assay for detecting significant changes in gene expression and confirmed expression in tissues using immunohistochemistry and real-time PCR. We transfected or injected the silencing BTF3 (BTF3-siRNA) plasmid into cells and nude mice, and measured the tumorigenicity of CRC cells with flow cytometry and studied the expression level of BTF3 downstream genes (MAD2L2, MCM3 and PLK1) in CRC cells. BTF3 expression level was not only significantly higher in CRC tissue than in ANCT tissue (2.61 ± 0.07 vs 1.90 ± 0.03, P < 0.001) but BTF3-siRNA decreased tumor formation in a nude mice model. Furthermore, based on the data of gene microarray analysis, MAD2L2, MCM3 and PLK1 were detected as the downstream target genes of BTF3 and their expressions were positive related with BTF3 expression. Also, through transfecting BTF3-siRNA into HCT116 cells, we found that BTF3-siRNA could decrease cell viability and induced cell apoptosis and blocking the cell cycle. In conclusion, BTF3 is positively related to CRC and BTF3-siRNA attenuated the tumorigenicity of colorectal cancer cells via MAD2L2, MCM3 and PLK1 activity reduction.
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Affiliation(s)
- Qi Liu
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China.
| | - Junjie Wu
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
| | - Tailiang Lu
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
| | - Zhixue Fang
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
| | - Zixuan Huang
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
| | - Shanzheng Lu
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
| | - Chen Dai
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
| | - Mengqian Li
- Department of General Surgery, People's Hospital of Hunan Province, First Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, China
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10
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Transcription initiation factor TBP: old friend new questions. Biochem Soc Trans 2019; 47:411-423. [DOI: 10.1042/bst20180623] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/02/2019] [Accepted: 01/04/2019] [Indexed: 12/14/2022]
Abstract
Abstract
In all domains of life, the regulation of transcription by DNA-dependent RNA polymerases (RNAPs) is achieved at the level of initiation to a large extent. Whereas bacterial promoters are recognized by a σ-factor bound to the RNAP, a complex set of transcription factors that recognize specific promoter elements is employed by archaeal and eukaryotic RNAPs. These initiation factors are of particular interest since the regulation of transcription critically relies on initiation rates and thus formation of pre-initiation complexes. The most conserved initiation factor is the TATA-binding protein (TBP), which is of crucial importance for all archaeal-eukaryotic transcription initiation complexes and the only factor required to achieve full rates of initiation in all three eukaryotic and the archaeal transcription systems. Recent structural, biochemical and genome-wide mapping data that focused on the archaeal and specialized RNAP I and III transcription system showed that the involvement and functional importance of TBP is divergent from the canonical role TBP plays in RNAP II transcription. Here, we review the role of TBP in the different transcription systems including a TBP-centric discussion of archaeal and eukaryotic initiation complexes. We furthermore highlight questions concerning the function of TBP that arise from these findings.
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11
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Chen P, Zhong Q, Li Z, Zhang Y, Huang Z. Expression and clinical significance of basic transcription factor 3 in nasopharyngeal carcinoma. Oncol Lett 2018; 17:789-796. [PMID: 30655831 PMCID: PMC6312943 DOI: 10.3892/ol.2018.9699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/15/2018] [Indexed: 12/28/2022] Open
Abstract
Basic transcription factor 3 (BTF3), a transcription factor and modulator of apoptosis, is differentially expressed in carcinoma. To acquire further understanding of the involvement of BTF3 in carcinoma, the present study analyzed the expression of BTF3, as well as its role in cell function in nasopharyngeal carcinoma (NPC). BTF3 transcription rates in human NPC samples (n=46) and adjacent normal tissue samples (n=46) were analyzed using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. BTF3-silencing in NPC cells was performed via specific small interfering RNA molecules. The function of BTF3 was analyzed by proliferation assays and colony forming assays using a Cellomic assay system. The positive expression rates of BTF3 were significantly increased in cancerous tissues compared with those in adjacent tissues (P<0.05). In addition, BTF3-silencing decreased cell proliferation and colony formation (P<0.01) in TCA-8113 and 5–8F cells. BTF3 is overexpressed in NPC, and its silencing is associated with decreased cell proliferation and colony formation, enhanced apoptosis and cell cycle regulation of TCA-8113 and 5–8F cells.
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Affiliation(s)
- Ping Chen
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, P.R. China
| | - Qi Zhong
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, P.R. China
| | - Zufei Li
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, P.R. China
| | - Yang Zhang
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, P.R. China
| | - Zhigang Huang
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, P.R. China
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12
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Li X, Sui J, Xing J, Cao F, Wang H, Fu C, Wang H. Basic transcription factor 3 expression silencing attenuates colon cancer cell proliferation and migration in vitro. Oncol Lett 2018; 17:113-118. [PMID: 30655745 PMCID: PMC6313191 DOI: 10.3892/ol.2018.9613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 07/27/2018] [Indexed: 12/14/2022] Open
Abstract
Basic transcription factor 3 (BTF3) is an RNA polymerase II transcription factor that also regulates apoptosis. Numerous studies have identified that BTF3 is aberrantly expressed in several types of tumor. However, the function of BTF3 in colorectal cancer remains unknown. The aim of the present study was to assess the function of BTF3 during colon cancer tumorigenesis. Applying a lentivirus-transfected short hairpin RNA approach, expression of BTF3 was dysregulated in the colon cancer HCT116 and HT-29 cell lines; knockdown efficiency was verified using the quantitative polymerase chain reaction and western blotting. To determine the function of BTF3 in colon cancer, cell proliferation was assessed using an MTT assay, cell apoptosis and the cell cycle were assessed using flow cytometry, and cell migration was assessed using a Transwell assay. Knockdown of BTF3 inhibited cell proliferation, possibly because BTF3 knockdown induced cell early apoptosis and arrested cells in G0-G1 phase. BTF3 knockdown also inhibited cell migration. The results of the present study identified that BTF3 expression is associated with colon cancer progress, and BTF3 may therefore be a molecular marker for diagnosis and treatment outcomes of human colon cancer.
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Affiliation(s)
- Xu Li
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
| | - Jinke Sui
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
| | - Junjie Xing
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
| | - Fuao Cao
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
| | - Hao Wang
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
| | - Chuangang Fu
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
| | - Hantao Wang
- Department of Colorectal Surgery, Changhai Hospital, Shanghai 200433, P.R. China
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13
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Ding J, Wang X, Zhang Y, Sang X, Yi J, Liu C, Liu Z, Wang M, Zhang N, Xue Y, Shen L, Zhao W, Luo F, Liu P, Cheng H. Inhibition of BTF3 sensitizes luminal breast cancer cells to PI3Kα inhibition through the transcriptional regulation of ERα. Cancer Lett 2018; 440-441:54-63. [PMID: 30315845 DOI: 10.1016/j.canlet.2018.09.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 09/07/2018] [Accepted: 09/26/2018] [Indexed: 02/07/2023]
Abstract
Selective phosphatidylinositol 3 kinase (PI3K) inhibitors are being actively tested in clinical trials for ERα-positive (ER+) breast cancer due to the presence of activating PIK3CA mutations. However, recent studies have revealed that increased ERα transcriptional activity limits the efficacy of PI3K inhibitor monotherapy for ER + breast cancers. Herein, we report the identification of BTF3 as an oncogenic transcription factor that regulates ERα expression in luminal breast cancers. Our TCGA analysis reveals high expression levels of BTF3 in luminal/ER + breast cancer and cell line models harboring ERα overexpression. Concordantly, BTF3 expression is highly and strongly associated with ESR1 expression in multiple breast cancer cohorts. We further show that BTF3 promotes the proliferation, survival and migration of ER + breast cancer cells by modulating ESR1 expression and ERα-dependent transcription. Moreover, BTF3 knockdown sensitizes ER + breast cancer cells to the PI3Kα inhibitor BYL-719 in both in vitro and in vivo models. Together, our findings highlight a novel role of BTF3 in modulation of ERα-dependent transcriptional activity and its potential as a predictive marker for the response to PI3K-targeted therapy in ER + breast cancer.
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Affiliation(s)
- Jinlei Ding
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Xiaonan Wang
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Yuan Zhang
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Xiaolin Sang
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Jingyan Yi
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Chongya Liu
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Zundong Liu
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Min Wang
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Nan Zhang
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Yijue Xue
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Lanlin Shen
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China
| | - Wenzhi Zhao
- Department of Orthopedics, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Fuwen Luo
- Department of Acute Abdomen Surgery, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Pixu Liu
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China; College of Pharmacy, Dalian Medical University, Dalian, Liaoning, China.
| | - Hailing Cheng
- Cancer Institute, The Second Hospital of Dalian Medical University, Dalian Key Laboratory of Molecular Targeted Cancer Therapy, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning, China.
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14
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Gap junction protein Connexin-43 is a direct transcriptional regulator of N-cadherin in vivo. Nat Commun 2018; 9:3846. [PMID: 30242148 PMCID: PMC6155008 DOI: 10.1038/s41467-018-06368-x] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 08/29/2018] [Indexed: 11/16/2022] Open
Abstract
Connexins are the primary components of gap junctions, providing direct links between cells under many physiological processes. Here, we demonstrate that in addition to this canonical role, Connexins act as transcriptional regulators. We show that Connexin 43 (Cx43) controls neural crest cell migration in vivo by directly regulating N-cadherin transcription. This activity requires interaction between Cx43 carboxy tail and the basic transcription factor-3, which drives the translocation of Cx43 tail to the nucleus. Once in the nucleus they form a complex with PolII which directly binds to the N-cadherin promoter. We found that this mechanism is conserved between amphibian and mammalian cells. Given the strong evolutionary conservation of connexins across vertebrates, this may reflect a common mechanism of gene regulation by a protein whose function was previously ascribed only to gap junctional communication. Connexins are components of gap junctions that link cells and allow intercellular communication. Here, the authors show that the Connexin 43 carboxy tail interacts with basic transcription factor-3, leading to nuclear translocation and direct regulation of N-cadherin expression and neural crest migration.
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15
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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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16
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Jeon YJ, Bang W, Cho JH, Lee RH, Kim SH, Kim MS, Park SM, Shin JC, Chung HJ, Oh KB, Seo JM, Ko S, Shim JH, Chae JI. Kahweol induces apoptosis by suppressing BTF3 expression through the ERK signaling pathway in non-small cell lung cancer cells. Int J Oncol 2016; 49:2294-2302. [DOI: 10.3892/ijo.2016.3727] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/04/2016] [Indexed: 11/06/2022] Open
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17
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Abstract
Transcription of eukaryotic protein-coding genes commences with the assembly of a conserved initiation complex, which consists of RNA polymerase II (Pol II) and the general transcription factors, at promoter DNA. After two decades of research, the structural basis of transcription initiation is emerging. Crystal structures of many components of the initiation complex have been resolved, and structural information on Pol II complexes with general transcription factors has recently been obtained. Although mechanistic details await elucidation, available data outline how Pol II cooperates with the general transcription factors to bind to and open promoter DNA, and how Pol II directs RNA synthesis and escapes from the promoter.
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18
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Perturbation of discrete sites on a single protein domain with RNA aptamers: targeting of different sides of the TATA-binding protein (TBP). Biosci Biotechnol Biochem 2013; 77:1739-46. [PMID: 23924740 DOI: 10.1271/bbb.130296] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Control of interactions among proteins is critical in the treatment of diseases, but the specificity required is not easily incorporated into small molecules. Macromolecules could be more suitable as antagonists in this situation, and RNA aptamers have become particularly promising. Here we describe a novel selection procedure for RNA aptamers against a protein that constitutes a single structural domain, the Drosophila TATA-binding protein (TBP). In addition to the conventional filter partitioning method with free TBP as target, we performed another experiment, in which the TATA-bound form of TBP was targeted. Aptamers generated by both selections were able to bind specifically to TBP, but the two groups showed characteristics which were clearly different in terms of their capability to compete with TATA-DNA, their effects on the TATA-bound form of TBP, and their effects on in vitro transcription. The method used to generate these two groups of aptamers can be used with other targets to direct aptamer specificity to discrete sites on the surface of a protein.
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19
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Liu Q, Zhou JP, Li B, Huang ZC, Dong HY, Li GY, Zhou K, Nie SL. Basic transcription factor 3 is involved in gastric cancer development and progression. World J Gastroenterol 2013; 19:4495-4503. [PMID: 23901224 PMCID: PMC3725373 DOI: 10.3748/wjg.v19.i28.4495] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/25/2013] [Accepted: 06/04/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To further analyse cancer involvement of basic transcription factor 3 (BTF3) after detection of its upregulation in gastric tumor samples.
METHODS: BTF3 transcription rates in human gastric tumor tissue samples (n = 20) and adjacent normal tissue (n = 18) specimens as well as in the gastric cancer cell lines AGS, SGC-7901, MKN-28, MKN-45 and MGC803 were analyzed via quantitative real-time polymerase chain reaction. The effect of stable BTF3 silencing via infection with a small interfering RNA (siRNA)-BTF3 expressing lentivirus on SGC-7901 cells was measured via Western blotting analysis, proliferation assays, cell cycle and apoptosis profiling by flow cytometry as well as colony forming assays with a Cellomic Assay System.
RESULTS: A significant higher expression of BTF3 mRNA was detected in tumors compared to normal gastric tissues (P < 0.01), especially in section tissues from female patients compared to male patients, and all tested gastric cancer cell lines expressed high levels of BTF3. From days 1 to 5, the relative proliferation rates of stable BTF3-siRNA transfected SGC7901 cells were 82%, 70%, 57%, 49% and 44% compared to the control, while the percentage of cells arrested in the G1 phase was significantly decreased (P = 0.000) and the percentages of cells in the S (P = 0.031) and G2/M (P = 0.027) phases were significantly increased. In addition, the colony forming tendency was significantly decreased (P = 0.014) and the apoptosis rate increased from 5.73% to 8.59% (P = 0.014) after BTF3 was silenced in SGC7901 cells.
CONCLUSION: BTF3 expression is associated with enhanced cell proliferation, reduced cell cycle regulation and apoptosis and its silencing decreased colony forming and proliferation of gastric cancer cells.
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20
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Quantitative proteomic analysis of induced pluripotent stem cells derived from a human Huntington's disease patient. Biochem J 2012; 446:359-71. [PMID: 22694310 DOI: 10.1042/bj20111495] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
HD (Huntington's disease) is a devastating neurodegenerative genetic disorder caused by abnormal expansion of CAG repeats in the HTT (huntingtin) gene. We have recently established two iPSC (induced pluripotent stem cell) lines derived from a HD patient carrying 72 CAG repeats (HD-iPSC). In order to understand the proteomic profiles of HD-iPSCs, we have performed comparative proteomic analysis among normal hESCs (human embryonic stem cells; H9), iPSCs (551-8) and HD-iPSCs at undifferentiated stages, and identified 26 up- and down-regulated proteins. Interestingly, these differentially expressed proteins are known to be involved in different biological processes, such as oxidative stress, programmed cell death and cellular oxygen-associated proteins. Among them, we found that oxidative stress-related proteins, such as SOD1 (superoxide dismutase 1) and Prx (peroxiredoxin) families are particularly affected in HD-iPSCs, implying that HD-iPSCs are highly susceptible to oxidative stress. We also found that BTF3 (basic transcription factor 3) is up-regulated in HD-iPSCs, which leads to the induction of ATM (ataxia telangiectasia mutated), followed by activation of the p53-mediated apoptotic pathway. In addition, we observed that the expression of cytoskeleton-associated proteins was significantly reduced in HD-iPSCs, implying that neuronal differentiation was also affected. Taken together, these results demonstrate that HD-iPSCs can provide a unique cellular disease model system to understand the pathogenesis and neurodegeneration mechanisms in HD, and the identified proteins from the present study may serve as potential targets for developing future HD therapeutics.
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21
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Thakur D, Saxena R, Singh V, Haq W, Katti SB, Singh BN, Tripathi RK. Human beta casein fragment (54-59) modulates M. bovis BCG survival and basic transcription factor 3 (BTF3) expression in THP-1 cell line. PLoS One 2012; 7:e45905. [PMID: 23029305 PMCID: PMC3461027 DOI: 10.1371/journal.pone.0045905] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 08/27/2012] [Indexed: 12/15/2022] Open
Abstract
Immunostimulatory peptides potentiate the immune system of the host and are being used as a viable adjunct to established therapeutic modalities in treatment of cancer and microbial infections. Several peptides derived from milk protein have been reported to induce immunostimulatory activity. Human β -casein fragment (54–59), natural sequence peptide (NS) carrying the Val-Glu-Pro-Ile-Pro-Tyr amino acid residues, was reported to activate the macrophages and impart potent immunostimulatory activity. In present study, we found that this peptide increases the clearance of M. bovis BCG from THP-1 cell line in vitro. The key biomolecules, involved in the clearance of BCG from macrophage like, nitric oxide, pro-inflammatory cytokines and chemokines, were not found to be significantly altered after peptide treatment in comparison to the untreated control. Using proteomic approach we found that BTF3a, an isoform of the Basic Transcription Factor, BTF3, was down regulated in THP-1 cell line after peptide treatment. This was reconfirmed by real time RT-PCR and western blotting. We report the BTF3a as a novel target of this hexapeptide. Based on the earlier findings and the results from the present studies, we suggest that the down regulation of BTF3a following the peptide treatment may augment the M. bovis BCG mediated apoptosis resulting in enhanced clearance of M. bovis BCG from THP-1 cell line.
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Affiliation(s)
| | - Reshu Saxena
- Division of Toxicology, Central Drug Research Institute, Lucknow, India
| | - Vandana Singh
- Division of Microbiology, Central Drug Research Institute, Lucknow, India
| | - Wahajul Haq
- Division of Medicinal and Process Chemistry, Central Drug Research Institute, Lucknow, India
| | - S. B. Katti
- Division of Medicinal and Process Chemistry, Central Drug Research Institute, Lucknow, India
| | - Bhupendra Narain Singh
- Division of Microbiology, Central Drug Research Institute, Lucknow, India
- * E-mail: (BNS); (RKT)
| | - Raj Kamal Tripathi
- Division of Toxicology, Central Drug Research Institute, Lucknow, India
- * E-mail: (BNS); (RKT)
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NER factors are recruited to active promoters and facilitate chromatin modification for transcription in the absence of exogenous genotoxic attack. Mol Cell 2010; 38:54-66. [PMID: 20385089 DOI: 10.1016/j.molcel.2010.03.004] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 12/01/2009] [Accepted: 03/02/2010] [Indexed: 11/20/2022]
Abstract
Upon gene activation, we found that RNA polymerase II transcription machinery assembles sequentially with the nucleotide excision repair (NER) factors at the promoter. This recruitment occurs in absence of exogenous genotoxic attack, is sensitive to transcription inhibitors, and depends on the XPC protein. The presence of these repair proteins at the promoter of activated genes is necessary in order to achieve optimal DNA demethylation and histone posttranslational modifications (H3K4/H3K9 methylation, H3K9/14 acetylation) and thus efficient RNA synthesis. Deficiencies in some NER factors impede the recruitment of others and affect nuclear receptor transactivation. Our data suggest that there is a functional difference between the presence of the NER factors at the promoters (which requires XPC) and the NER factors at the distal regions of the gene (which requires CSB). While the latter may be a repair function, the former is a function with respect to transcription unveiled in the current study.
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23
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Abstract
In eukaryotes, the core promoter serves as a platform for the assembly of transcription preinitiation complex (PIC) that includes TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, and RNA polymerase II (pol II), which function collectively to specify the transcription start site. PIC formation usually begins with TFIID binding to the TATA box, initiator, and/or downstream promoter element (DPE) found in most core promoters, followed by the entry of other general transcription factors (GTFs) and pol II through either a sequential assembly or a preassembled pol II holoenzyme pathway. Formation of this promoter-bound complex is sufficient for a basal level of transcription. However, for activator-dependent (or regulated) transcription, general cofactors are often required to transmit regulatory signals between gene-specific activators and the general transcription machinery. Three classes of general cofactors, including TBP-associated factors (TAFs), Mediator, and upstream stimulatory activity (USA)-derived positive cofactors (PC1/PARP-1, PC2, PC3/DNA topoisomerase I, and PC4) and negative cofactor 1 (NC1/HMGB1), normally function independently or in combination to fine-tune the promoter activity in a gene-specific or cell-type-specific manner. In addition, other cofactors, such as TAF1, BTAF1, and negative cofactor 2 (NC2), can also modulate TBP or TFIID binding to the core promoter. In general, these cofactors are capable of repressing basal transcription when activators are absent and stimulating transcription in the presence of activators. Here we review the roles of these cofactors and GTFs, as well as TBP-related factors (TRFs), TAF-containing complexes (TFTC, SAGA, SLIK/SALSA, STAGA, and PRC1) and TAF variants, in pol II-mediated transcription, with emphasis on the events occurring after the chromatin has been remodeled but prior to the formation of the first phosphodiester bond.
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Affiliation(s)
- Mary C Thomas
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4935, USA
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24
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The right tools for the job. Nat Rev Mol Cell Biol 2005. [DOI: 10.1038/nrm1801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Fan X, Shi H, Lis JT. Distinct transcriptional responses of RNA polymerases I, II and III to aptamers that bind TBP. Nucleic Acids Res 2005; 33:838-45. [PMID: 15701755 PMCID: PMC549393 DOI: 10.1093/nar/gki212] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The TATA-binding protein (TBP) is a general factor that is involved in transcription by all three types of nuclear RNA polymerase. To delineate the roles played by the DNA-binding surface of TBP in these transcription reactions, we used a set of RNA aptamers directed against TBP and examined their ability to perturb transcription in vitro by the different RNA polymerases. Distinct responses to the TBP aptamers were observed for transcription by different types of polymerase at either the initiation, reinitiation or both stages of the transcription cycle. We further probed the TBP interactions in the TFIIIB•DNA complex to elucidate the mechanism for the different sensitivity of Pol III dependent transcription before and after preinitiation complex (PIC) formation. Lastly, the aptamers were employed to measure the time required for Pol III PIC formation in vitro. This approach can be generalized to define the involvement of a particular region on the surface of a protein at particular stages in a biological process.
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Affiliation(s)
| | | | - John T. Lis
- To whom correspondence should be addressed. Tel: +1 607 255 2442; Fax: +1 607 255 6249;
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26
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Affiliation(s)
- Pierre Chambon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, ULP, Collège de France, Strasbourg.
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27
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Matangkasombut O, Auty R, Buratowski S. Structure and Function of the TFIID Complex. ADVANCES IN PROTEIN CHEMISTRY 2004; 67:67-92. [PMID: 14969724 DOI: 10.1016/s0065-3233(04)67003-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Oranart Matangkasombut
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02215, USA
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28
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Lachke SA, Srikantha T, Soll DR. The regulation of EFG1 in white-opaque switching in Candida albicans involves overlapping promoters. Mol Microbiol 2003; 48:523-36. [PMID: 12675809 DOI: 10.1046/j.1365-2958.2003.t01-1-03448.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
EFG1, which encodes a trans-acting factor, is expressed as a more abundant 3.2 kb transcript in the white phase and as a less abundant 2.2 kb transcript in the opaque phase of the white-opaque transition in Candida albicans. To understand how alternative phase-specific mRNAs are transcribed from the same gene locus, the 2320 bp upstream region of the gene was functionally characterized by analysing the -activity of deletion derivatives in a luciferase-based reporter system. The white phase-specific promoter contained three discrete sequences involved in white phase-specific activation, between -2022 and -1809 bp (AR1), between -1809 and -1727 bp (AR2) and between -922 and -840 bp (AR3). A higher resolution deletion and mutation analysis of AR2 revealed two regions between -1809 and -1787 bp and between -1764 and -1728 bp that are responsible for AR2 activation. Targeting of promoter constructs to the ectopic ADE2 genomic site and the 3' end of the EFG1 genomic site revealed a positional requirement for white phase-regulated activation specific for the AR2 region of the promoter. Gel mobility shift assays using AR2 revealed a white phase-specific activation complex. No discrete activation sequences were identified in the overlapping promoter of the opaque phase-specific EFG1 transcript. The strength of opaque phase activation was directly proportional to the length of the promoter. Northern analysis excluded the possibility of an opaque phase-specific repressor. These results demonstrate overlapping promoters for white and opaque phase-specific expression of the gene for the transcription factor Efg1, with distinctly different mechanisms of phase-specific activation.
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Affiliation(s)
- Salil A Lachke
- Department of Biological Sciences, Rm 302 BBE, The University of Iowa, Iowa City, IA 52242, USA
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29
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Srikantha T, Tsai LK, Daniels K, Soll DR. EFG1 null mutants of Candida albicans switch but cannot express the complete phenotype of white-phase budding cells. J Bacteriol 2000; 182:1580-91. [PMID: 10692363 PMCID: PMC94455 DOI: 10.1128/jb.182.6.1580-1591.2000] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Candida albicans gene EFG1 encodes a putative trans-acting factor. In strain WO-1, which undergoes the white-opaque transition, EFG1 is transcribed as a 3.2-kb mRNA in white-phase cells and a less-abundant 2.2-kb mRNA in opaque-phase cells. cDNA sequencing and 5' rapid amplification of cDNA ends analysis demonstrate that the major difference in molecular mass of the two transcripts is due to different transcription start sites. EFG1 null mutants form opaque-phase colonies and express the opaque-phase cell phenotype at 25 degrees C. When shifted from 25 to 42 degrees C, mutant opaque-phase cells undergo phenotypic commitment to the white phase, which includes deactivation of the opaque-phase-specific gene OP4 and activation of the white-phase-specific gene WH11, as do wild-type opaque-phase cells. After the commitment event, EFG1 null mutant cells form daughter cells which have the smooth (pimpleless) surface of white-phase cells but the elongate morphology of opaque-phase cells. Taken together, these results demonstrate that EFG1 expression is not essential for the switch event per se, but is essential for a subset of phenotypic characteristics necessary for the full expression of the phenotype of white-phase cells. These results demonstrate that EFG1 is not the site of the switch event, but is, rather, downstream of the switch event.
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MESH Headings
- 5' Untranslated Regions/genetics
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Candida albicans/genetics
- Candida albicans/growth & development
- Candida albicans/metabolism
- Candida albicans/ultrastructure
- Colony Count, Microbial
- DNA, Complementary/genetics
- DNA-Binding Proteins
- Fungal Proteins/genetics
- Fungal Proteins/metabolism
- Gene Deletion
- Gene Expression Regulation, Fungal
- Microscopy, Electron, Scanning
- Molecular Sequence Data
- Mutation
- Phenotype
- Promoter Regions, Genetic
- Sequence Analysis, DNA
- Transcription Factors
- Transcription, Genetic
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Affiliation(s)
- T Srikantha
- Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242, USA
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30
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Moore PA, Ozer J, Salunek M, Jan G, Zerby D, Campbell S, Lieberman PM. A human TATA binding protein-related protein with altered DNA binding specificity inhibits transcription from multiple promoters and activators. Mol Cell Biol 1999; 19:7610-20. [PMID: 10523649 PMCID: PMC84787 DOI: 10.1128/mcb.19.11.7610] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/1999] [Accepted: 07/28/1999] [Indexed: 11/20/2022] Open
Abstract
The TATA binding protein (TBP) plays a central role in eukaryotic and archael transcription initiation. We describe the isolation of a novel 23-kDa human protein that displays 41% identity to TBP and is expressed in most human tissue. Recombinant TBP-related protein (TRP) displayed barely detectable binding to consensus TATA box sequences but bound with slightly higher affinities to nonconsensus TATA sequences. TRP did not substitute for TBP in transcription reactions in vitro. However, addition of TRP potently inhibited basal and activated transcription from multiple promoters in vitro and in vivo. General transcription factors TFIIA and TFIIB bound glutathione S-transferase-TRP in solution but failed to stimulate TRP binding to DNA. Preincubation of TRP with TFIIA inhibited TBP-TFIIA-DNA complex formation and addition of TFIIA overcame TRP-mediated transcription repression. TRP transcriptional repression activity was specifically reduced by mutations in TRP that disrupt the TFIIA binding surface but not by mutations that disrupt the TFIIB or DNA binding surface of TRP. These results suggest that TFIIA is a primary target of TRP transcription inhibition and that TRP may modulate transcription by a novel mechanism involving the partial mimicry of TBP functions.
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Affiliation(s)
- P A Moore
- Human Genome Sciences, Rockville, Maryland 20850, USA
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31
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Kim MK, Nikodem VM. hnRNP U inhibits carboxy-terminal domain phosphorylation by TFIIH and represses RNA polymerase II elongation. Mol Cell Biol 1999; 19:6833-44. [PMID: 10490622 PMCID: PMC84680 DOI: 10.1128/mcb.19.10.6833] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study describes a potential new function of hnRNP U as an RNA polymerase (Pol II) elongation inhibitor. We demonstrated that a subfraction of human hnRNP U is associated with the Pol II holoenzyme in vivo and as such recruited to the promoter as part of the preinitiation complex. hnRNP U, however, appears to dissociate from the Pol II complex at the early stage of transcription and is therefore absent from the elongating Pol II complex. When tested in the human immunodeficiency virus type 1 transcription system, hnRNP U inhibits elongation rather than initiation of transcription by Pol II. This inhibition requires the carboxy-terminal domain (CTD) of Pol II. We showed that hnRNP U can bind TFIIH in vivo under certain conditions and inhibit TFIIH-mediated CTD phosphorylation in vitro. We find that the middle domain of hnRNP U is sufficient to mediate its Pol II association and its inhibition of TFIIH-mediated phosphorylation and Pol II elongation. The abilities of hnRNP U to inhibit TFIIH-mediated CTD phosphorylation and its Pol II association are necessary for hnRNP U to mediate the repression of Pol II elongation. Based on these observations, we suggest that a subfraction of hnRNP U, as a component of the Pol II holoenzyme, may downregulate TFIIH-mediated CTD phosphorylation in the basal transcription machinery and repress Pol II elongation. With such functions, hnRNP U might provide one of the mechanisms by which the CTD is maintained in an unphosphorylated state in the Pol II holoenzyme.
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Affiliation(s)
- M K Kim
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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32
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Dantonel JC, Wurtz JM, Poch O, Moras D, Tora L. The TBP-like factor: an alternative transcription factor in metazoa? Trends Biochem Sci 1999; 24:335-9. [PMID: 10470030 DOI: 10.1016/s0968-0004(99)01436-x] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Protein sequence analysis has revealed a family of TATA-binding-protein (TBP)-like factors (TLFs) in metazoan organisms. Modelling of the three-dimensional structure of these TLFs suggests that they form an asymmetric saddle-like structure and that, unlike TBP, TLFs might bind to DNA sequences other than classical TATA boxes. Thus, the existence of TLFs presents a challenge to the doctrine that TBP is a universal regulator of transcription in metazoans.
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Affiliation(s)
- J C Dantonel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP 163, F-67404 Illkirch, Cedex, C.U. de Strasbourg, France
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33
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Bell B, Tora L. Regulation of gene expression by multiple forms of TFIID and other novel TAFII-containing complexes. Exp Cell Res 1999; 246:11-9. [PMID: 9882510 DOI: 10.1006/excr.1998.4294] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- B Bell
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, C. U. de Strasbourg, F-67404, France
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34
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Lockhart SR, Nguyen M, Srikantha T, Soll DR. A MADS box protein consensus binding site is necessary and sufficient for activation of the opaque-phase-specific gene OP4 of Candida albicans. J Bacteriol 1998; 180:6607-16. [PMID: 9852005 PMCID: PMC107764 DOI: 10.1128/jb.180.24.6607-6616.1998] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The majority of strains of Candida albicans can switch frequently and reversibly between two or more general phenotypes, a process now considered a putative virulence factor in this species. Candida albicans WO-1 switches frequently and reversibly between a white and an opaque phase, and this phenotypic transition is accompanied by the differential expression of white-phase-specific and opaque-phase-specific genes. In the opaque phase, cells differentially express the gene OP4, which encodes a putative protein 402 amino acids in length that contains a highly hydrophobic amino-terminal sequence and a carboxy-terminal sequence with a pI of 10.73. A series of deletion constructs fused to the Renilla reniformis luciferase was used to functionally characterize the OP4 promoter in order to investigate how this gene is differentially expressed in the white-opaque transition. An extremely strong 17-bp transcription activation sequence was identified between -422 and -404 bp. This sequence contained a MADS box consensus binding site, most closely related to the Mcm1 binding site of Saccharomyces cerevisiae. A number of point mutations generated in the MADS box consensus binding site as well as a complete deletion of the consensus site further demonstrated that it was essential for the activation of OP4 transcription in the opaque phase. Gel mobility shift assays with the 17-bp activation sequence identified three specific complexes which formed with both white- and opaque-phase cell extracts. Competition with a putative MADS box consensus binding site from the promoter of the coordinately regulated opaque-phase-specific gene PEP1 (SAP1) and the human MADS box consensus binding site for serum response factor demonstrated that one of the three complexes formed was specific to the OP4 sequence.
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Affiliation(s)
- S R Lockhart
- Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242, USA
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35
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Abstract
Transcription initiation by RNA polymerase II (RNA pol II) requires interaction between cis-acting promoter elements and trans-acting factors. The eukaryotic promoter consists of core elements, which include the TATA box and other DNA sequences that define transcription start sites, and regulatory elements, which either enhance or repress transcription in a gene-specific manner. The core promoter is the site for assembly of the transcription preinitiation complex, which includes RNA pol II and the general transcription fctors TBP, TFIIB, TFIIE, TFIIF, and TFIIH. Regulatory elements bind gene-specific factors, which affect the rate of transcription by interacting, either directly or indirectly, with components of the general transcriptional machinery. A third class of transcription factors, termed coactivators, is not required for basal transcription in vitro but often mediates activation by a broad spectrum of activators. Accordingly, coactivators are neither gene-specific nor general transcription factors, although gene-specific coactivators have been described in metazoan systems. Transcriptional repressors include both gene-specific and general factors. Similar to coactivators, general transcriptional repressors affect the expression of a broad spectrum of genes yet do not repress all genes. General repressors either act through the core transcriptional machinery or are histone related and presumably affect chromatin function. This review focuses on the global effectors of RNA polymerase II transcription in yeast, including the general transcription factors, the coactivators, and the general repressors. Emphasis is placed on the role that yeast genetics has played in identifying these factors and their associated functions.
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Affiliation(s)
- M Hampsey
- Department of Biochemistry, Division of Nucleic Acids Enzymology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854-5635, USA.
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36
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Abstract
A previously isolated partial cDNA encoding a cell wall protein antigen found on hyphal surfaces of the opportunistic fungal pathogen, Candida albicans (Staab et al., 1996) was used to clone the complete hyphal wall protein 1 gene (HWP1). Hyphal forms of C. albicans invade mucosal surfaces of immunocompromised patients such as those with AIDS. HWP1 consisted of an open reading frame predicting an acidic protein (pI of 3.37) with a calculated molecular size of 61,122. The antigenic domain was located in the N-terminal third of the protein. The remainder of the protein contained abundant hydroxy amino acids, and terminated with a string of 15 amino acids typical of sequences specifying post-translational modification with glycosylphosphatidylinositol (6PI). The analyses suggested that Hwp1 is a glucan-linked protein with serine/threonine-rich regions that are predicted to function in extending a ligand-binding domain into the extracellular space.
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Affiliation(s)
- J F Staab
- Department of Medical Microbiology and Immunology, The Ohio State University College of Medicine, Columbus 43210-1239, USA
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37
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Teichmann M, Dieci G, Huet J, Rüth J, Sentenac A, Seifart KH. Functional interchangeability of TFIIIB components from yeast and human cells in vitro. EMBO J 1997; 16:4708-16. [PMID: 9303315 PMCID: PMC1170097 DOI: 10.1093/emboj/16.15.4708] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In eukaryotes, TFIIIB is required for proper initiation by RNA polymerase III. In the yeast Saccharomyces cerevisiae a single form of TFIIIB (gammaTFIIIB) is sufficient for transcription of all pol III genes, whereas in extracts derived from human cells two different hTFIIIB complexes exist which we have previously designated as hTFIIIB-alpha and hTFIIIB-beta. Human TFIIIB-alpha is a TBP-free entity and must be complemented by TBP for transcription of pol III genes driven by gene external promoters, whereas hTFIIIB-beta is a TBP-TAF complex which governs transcription from internal pol III promoters. We show that hTFIIIB-beta cannot be replaced by yeast TFIIIB for transcription of tRNA genes, but that the B" component of gammaTFIIIB can substitute for hTFIIIB-alpha activity in transcription of the human U6 gene. Moreover, hTFIIIB-alpha can be chromatographically divided into activities which are functionally related to gammaTFIIIE and recombinant yB"90, suggesting that hTFIIIB-alpha is a human homolog of yeast TFIIIB". In addition, we show that yeast TBP can only be exchanged against human TBP for in vitro transcription of the human and yeast U6 gene but virtually not for that of the yeast tRNA4Sup gene. This deficiency can be counteracted by a mutant of human TBP (R231K) which is able to replace yeast TBP for transcription of yeast tRNA genes in vitro.
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Affiliation(s)
- M Teichmann
- Institut für Molekularbiologie und Tumorforschung, Marburg/Lahn, Germany
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38
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Myers LC, Leuther K, Bushnell DA, Gustafsson CM, Kornberg RD. Yeast RNA polymerase II transcription reconstituted with purified proteins. Methods 1997; 12:212-6. [PMID: 9237165 DOI: 10.1006/meth.1997.0473] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Protocols are presented for the preparation of a fully defined yeast RNA polymerase II transcription system, consisting of essentially pure TFIIB, -E, -F, and -H, TATA-binding protein, RNA polymerase II, and mediator of transcriptional regulation. This system, comprising 44 polypeptides, is able to initiate transcription at any of a dozen yeast and mammalian promoters thus far tested and responds to a variety of transcriptional activator proteins.
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Affiliation(s)
- L C Myers
- Department of Structural Biology, Stanford University School of Medicine, California 94305, USA
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39
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Diagana TT. [Activation of transcription in eukaryotic cells: interactions between transcription factors and components of the basal transcriptional mechanism]. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 1997; 320:509-21. [PMID: 9309252 DOI: 10.1016/s0764-4469(97)84706-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Regulation of transcription in eucaryotes is achieved by two classes of transcription factors, GTFs (general transcription factors), which are components of the basal machinery, and sequence- and tissue-specific transcription factors. In this review, recent insights into the structure and function of components from the basal transcriptional machinery are discussed. The mechanisms of transcriptional activation involving direct interactions between trans-activators and the basal machinery are also presented.
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Affiliation(s)
- T T Diagana
- Département de Biologie Moléculaire, Institut Pasteur, Paris, France
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40
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Smale ST. Transcription initiation from TATA-less promoters within eukaryotic protein-coding genes. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1351:73-88. [PMID: 9116046 DOI: 10.1016/s0167-4781(96)00206-0] [Citation(s) in RCA: 430] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S T Smale
- Department of Microbiology and Immunology, University of California, Los Angeles School of Medicine 90095-1662, USA.
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41
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Soil DR. Gene regulation during high-frequency switching in Candida albicans. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 2):279-288. [PMID: 9043104 DOI: 10.1099/00221287-143-2-279] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- David R Soil
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA
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42
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Leuther KK, Bushnell DA, Kornberg RD. Two-dimensional crystallography of TFIIB- and IIE-RNA polymerase II complexes: implications for start site selection and initiation complex formation. Cell 1996; 85:773-9. [PMID: 8646784 DOI: 10.1016/s0092-8674(00)81242-8] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
SUMMARY Transcription factors IIB (TFIIB) and IIE (TFIIE) bound to RNA polymerase II have been revealed by electron crystallography in projection at 15.7 A resolution. The results lead to simple hypotheses for the roles of these factors in the initiation of transcription. TFIIB is suggested to define the distance from TATA box to transcription start site by bringing TATA DNA in contact with polymerase at that distance from the active center of the enzyme. TFIIE is suggested to participate in a key conformational switch occurring at the active center upon polymerase-DNA interaction.
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Affiliation(s)
- K K Leuther
- Department of Structural Biology, Stanford University School of Medicine, California 94305-5400, USA
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43
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Affiliation(s)
- H Zhang
- Center for Advanced Biotechnology and Medicine and Graduate Program in Molecular Genetics and Microbiology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854, USA
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44
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Abstract
Coactivators are a novel class of transcriptional activator required at many eukaryotic promoters. Several coactivators have now been isolated, their identification often facilitated by genetic studies in yeast. Some of the proposed mechanisms of coactivator function may help explain synergy between transcriptional activators at eukaryotic promoters.
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Affiliation(s)
- L Guarente
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139-4307, USA
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45
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Wang H, Peters GA, Zeng X, Tang M, Ip W, Khan SA. Yeast two-hybrid system demonstrates that estrogen receptor dimerization is ligand-dependent in vivo. J Biol Chem 1995; 270:23322-9. [PMID: 7559488 DOI: 10.1074/jbc.270.40.23322] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Previous studies using in vitro procedures have not clearly established whether the estrogen receptor (ER) acts as a monomer or dimer in the cell. We have used the yeast two-hybrid system as an in vivo approach to investigate the dimerization of the estrogen receptor in the absence and presence of estrogen and anti-estrogens. This system is independent of ER binding to the estrogen response element. Two vectors, expressing GAL4 DNA binding domain-human ER and GAL4 transactivation domain-human ER, were constructed. Control experiments showed that each fusion protein had a high affinity binding site for estradiol-17 beta and could transactivate an ERE-LacZ reporter gene in yeast similar to the wild type ER. The two fusion proteins, GAL4 DB-hER and GAL 4 TA-hER, were expressed in the yeast strain, PCY2, which carries a GAL1 promoter-lacZ reporter. ER dimerization was measured via reconstitution of GAL4 through interaction of the fusion proteins, which transactivates LacZ through the GAL1 promoter. When both ER fusion proteins were expressed, beta-galactosidase activity was estradiol-17 beta-inducible. Furthermore, we showed that both tamoxifen and ICI 182,780 also induced beta-galactosidase activity, albeit lower than that induced by estradiol-17 beta. These results strongly argue that ER dimerization is ligand-dependent and the dimer can be induced by estradiol-17 beta, tamoxifen, or ICI 182,780. We also treated the yeast containing the two fusion proteins with estradiol-17 beta and tamoxifen or ICI 182,780 simultaneously to determine the effects on ER dimerization. beta-Galactosidase activity was lower when the yeast was treated with a higher ratio of tamoxifen or ICI 182,780 to estrogen than estradiol-17 beta alone. Taken together, we conclude that ER dimerization is ligand (estradiol-17 beta, tamoxifen, or ICI 182, 780)-dependent, and we suggest that estradiol-17 beta-induced dimers are destabilized when estradiol-17 beta is used with tamoxifen or ICI 182,780 simultaneously.
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Affiliation(s)
- H Wang
- Department of Cell Biology, Neurobiology, and Anatomy, University of Cincinnati College of Medicine, Ohio 45267-0521, USA
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46
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Metzger D, Ali S, Bornert JM, Chambon P. Characterization of the amino-terminal transcriptional activation function of the human estrogen receptor in animal and yeast cells. J Biol Chem 1995; 270:9535-42. [PMID: 7721882 DOI: 10.1074/jbc.270.16.9535] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have previously reported that the transcriptional activation function AF-1, located in the A/B region of the human estrogen receptor, exhibits cell-type and promoter context specificity in both animal cells and yeast. To further characterize AF-1, we have constructed a number of deletion mutants spanning the A/B region in the context of either the whole human estrogen receptor or the A/B region linked to the GAL4 DNA binding domain, and tested their transcriptional activity in chicken embryo fibroblasts and in yeast cells, two cell types in which AF-1 efficiently activates transcription on its own. Additionally, we utilized HeLa cells in which AF-1 is poorly active but can synergize with the transcriptional activation function AF-2 located in the hormone binding domain. We show that in animal cells the "independent" activity of AF-1 is embodied in a rather hydrophobic proline-rich 99-amino acid activating domain (amino acids 51-149), whereas amino acids 51-93 and 102-149 can independently synergize with AF-2. Interestingly, in yeast, three discrete activating domains (amino acids 1-62, 80-113, and 118-149) are almost as active on their own as the whole A/B region, indicating that multiple activating domains can operate independently in yeast. Our study also demonstrates that, within the context of the whole human estrogen receptor, the same AF-1 activating domains are "induced" by either estradiol or 4-hydroxytamoxifen.
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Affiliation(s)
- D Metzger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Collège de France, Illkirch, C.U. de Strasbourg
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47
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Srikantha T, Chandrasekhar A, Soll DR. Functional analysis of the promoter of the phase-specific WH11 gene of Candida albicans. Mol Cell Biol 1995; 15:1797-805. [PMID: 7862169 PMCID: PMC230404 DOI: 10.1128/mcb.15.3.1797] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Candida albicans WO-1 switches spontaneously, frequently, and reversibly between a hemispherical white and a flat gray (opaque) colony-forming phenotype. This transition affects a number of morphological and physiological parameters and involves the activation and deactivation of phase-specific genes. The WH11 gene is transcribed in the white but not the opaque phase. A chimeric WH11-firefly luciferase gene containing the 5' upstream region of WH11 was demonstrated to be under phase regulation regardless of the site of integration, and a series of promoter deletion constructs was used to delineate two white-phase-specific transcription activation domains. Gel retardation experiments with the individual distal or proximal domain and white-phase or opaque-phase protein extract demonstrated the formation of one distal white-phase-specific complex and two proximal white-phase-specific complexes. Specific subfragments were tested for their ability to compete with the entire domain in the formation of complexes with white-phase protein extract in order to map the proximal domain sequence involved in white-phase-specific complex formation. Our results indicate that white-phase-specific transcription of WH11 is positively regulated by trans-acting factors interacting with two cis-acting activation sequences in the WH11 promoter.
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Affiliation(s)
- T Srikantha
- Department of Biological Sciences, University of Iowa, Iowa City 52242
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48
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Functional substitution of an essential yeast RNA polymerase subunit by a highly conserved mammalian counterpart. Mol Cell Biol 1994. [PMID: 8196653 DOI: 10.1128/mcb.14.6.4155] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We isolated the cDNA encoding the homolog of the Saccharomyces cerevisiae nuclear RNA polymerase common subunit RPB6 from hamster CHO cells. Alignment of yeast RPB6 with its mammalian counterpart revealed that the subunits have nearly identical carboxy-terminal halves and a short acidic region at the amino terminus. Remarkably, the length and amino acid sequence of the hamster RPB6 are identical to those of the human RPB6 subunit. The conservation in sequence from lower to higher eukaryotes also reflects conservation of function in vivo, since hamster RPB6 supports normal wild-type yeast cell growth in the absence of the essential gene encoding RPB6.
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49
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Cormack BP, Strubin M, Stargell LA, Struhl K. Conserved and nonconserved functions of the yeast and human TATA-binding proteins. Genes Dev 1994; 8:1335-43. [PMID: 7926734 DOI: 10.1101/gad.8.11.1335] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Although the TATA-binding protein (TBP) is highly conserved throughout the eukaryotic kingdom, human TBP cannot functionally replace yeast TBP for cell viability. To investigate the basis of this species specificity, we examine the in vivo transcriptional activity of human TBP at different classes of yeast promoters. Consistent with previous results, analysis of yeast/human hybrid TBPs indicates that growth defects are not correlated with the ability to promote TATA-dependent polymerase II (Pol II) transcription or to respond to acidic activator proteins. Human TBP partially complements the growth defects of a yeast TBP mutant with altered TATA element-binding specificity, suggesting that it carries out sufficient Pol II function to support viability. However, human TBP does not complement the defects of yeast TBP mutants that are specifically defective in transcription by RNA polymerase III. Three independently isolated derivatives of human TBP that permit yeast cell growth replace arginine 231 with lysine; the corresponding amino acid in yeast TBP (lysine 133) has been implicated in RNA polymerase III transcription. Transcriptional analysis indicates that human TBP functions poorly at promoters recognized by RNA polymerases I and III and at RNA Pol II promoters lacking a conventional TATA element. These observations suggest that species specificity of TBP primarily reflects evolutionarily diverged interactions with TBP-associated factors (TAFs) that are necessary for recruitment to promoters lacking TATA elements.
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Affiliation(s)
- B P Cormack
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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50
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McKune K, Woychik NA. Functional substitution of an essential yeast RNA polymerase subunit by a highly conserved mammalian counterpart. Mol Cell Biol 1994; 14:4155-9. [PMID: 8196653 PMCID: PMC358781 DOI: 10.1128/mcb.14.6.4155-4159.1994] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We isolated the cDNA encoding the homolog of the Saccharomyces cerevisiae nuclear RNA polymerase common subunit RPB6 from hamster CHO cells. Alignment of yeast RPB6 with its mammalian counterpart revealed that the subunits have nearly identical carboxy-terminal halves and a short acidic region at the amino terminus. Remarkably, the length and amino acid sequence of the hamster RPB6 are identical to those of the human RPB6 subunit. The conservation in sequence from lower to higher eukaryotes also reflects conservation of function in vivo, since hamster RPB6 supports normal wild-type yeast cell growth in the absence of the essential gene encoding RPB6.
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Affiliation(s)
- K McKune
- Roche Institute of Molecular Biology, Nutley, New Jersey 07110
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