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Mitra P, Banerjee S, Khandavalli C, Deshmukh AS. The role of Toxoplasma TFIIS-like protein in the early stages of mRNA transcription. Biochim Biophys Acta Gen Subj 2022; 1866:130240. [PMID: 36058424 DOI: 10.1016/j.bbagen.2022.130240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/25/2022] [Accepted: 08/28/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND The mRNA transcription is a multistep process involving distinct sets of proteins associated with RNA polymerase II (RNAPII) through various stages. Recent studies have highlighted the role of RNAPII-associated proteins in facilitating the assembly of functional complexes in a crowded nuclear milieu. RNAPII dynamics and gene expression regulation have been primarily studied in model eukaryotes like yeasts and mammals and remain largely unchartered in protozoan parasites like Toxoplasma gondii, where considerable gene expression changes accompany stage differentiations. Here we report a key modulator of RNAPII activity, TFIIS in Toxoplasma gondii (TgTFIIS). METHODS A Pull-down assay demonstrated that TgTFIIS binds to RNAPII subunit TgRPB1. Truncation mutants of TFIIS help us define the regions critical for its binding to TgRPB1. Co-immunoprecipitation analysis confirmed the interaction between the native TgTFIIS and TgRPB1. Confocal microscopy revealed a predominantly nuclear localization. Native TgTFIIS was able to bind promoter DNA which was consistent with the CHIP results. RESULTS TgTFIIS complements initiation defects in yeast mutants, and the regions implicated in RNAPII binding appeared essential for this function. Interestingly, the C-terminal zinc finger domain necessary for its potential elongation function is dispensable for TgRPB1 binding. TgTFIIS was found to be associated with the promoter region along with its association with the ORF on an RNAPII transcribed gene. CONCLUSION The observations were in line with the potential role of TgTFIIS in early events of RNAPII transcription in addition to elongation. GENERAL SIGNIFICANCE The study elucidates the potential role of RNAPII-associated proteins in multiple steps of transcription.
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Affiliation(s)
- Pallabi Mitra
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India.
| | - Sneha Banerjee
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Chittiraju Khandavalli
- DBT-National Institute of Animal Biotechnology, Hyderabad, India; Dept. of Graduate Studies, Regional Centre for Biotechnology, Faridabad, Haryana, India
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2
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Hou X, Xia J, Feng Y, Cui L, Yang Y, Yang P, Xu X. USP47-Mediated Deubiquitination and Stabilization of TCEA3 Attenuates Pyroptosis and Apoptosis of Colorectal Cancer Cells Induced by Chemotherapeutic Doxorubicin. Front Pharmacol 2021; 12:713322. [PMID: 34630087 PMCID: PMC8495243 DOI: 10.3389/fphar.2021.713322] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 09/10/2021] [Indexed: 12/31/2022] Open
Abstract
The ubiquitin–proteasome system regulates a variety of cellular processes including growth, differentiation and apoptosis. While E1, E2, and E3 are responsible for the conjugation of ubiquitin to substrates, deubiquitinating enzymes (DUBs) reverse the process to remove ubiquitin and edit ubiquitin chains, which have profound effects on substrates’ degradation, localization, and activities. In the present study, we found that the deubiquitinating enzyme USP47 was markedly decreased in primary colorectal cancers (CRC). Its reduced expression was associated with shorter disease-free survival of CRC patients. In cultured CRC cells, knockdown of USP47 increased pyroptosis and apoptosis induced by chemotherapeutic doxorubicin. We found that USP47 was able to bind with transcription elongation factor a3 (TCEA3) and regulated its deubiquitination and intracellular level. While ectopic expression of USP47 increased cellular TCEA3 and resistance to doxorubicin, the effect was markedly attenuated by TCEA3 knockdown. Further analysis showed that the level of pro-apoptotic Bax was regulated by TCEA3. These results indicated that the USP47-TCEA3 axis modulates cell pyroptosis and apoptosis and may serve as a target for therapeutic intervention in CRC.
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Affiliation(s)
- Xiaodan Hou
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences, Suzhou, China
| | - Jun Xia
- Department of Emergency Medicine, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yuan Feng
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences, Suzhou, China
| | - Long Cui
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yili Yang
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences, Suzhou, China.,China Regional Research Centre, International Centre of Genetic Engineering and Biotechnology, Taizhou, China
| | - Peng Yang
- Department of Emergency Medicine, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xin Xu
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences, Suzhou, China.,China Regional Research Centre, International Centre of Genetic Engineering and Biotechnology, Taizhou, China
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3
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Zatreanu D, Han Z, Mitter R, Tumini E, Williams H, Gregersen L, Dirac-Svejstrup AB, Roma S, Stewart A, Aguilera A, Svejstrup JQ. Elongation Factor TFIIS Prevents Transcription Stress and R-Loop Accumulation to Maintain Genome Stability. Mol Cell 2019; 76:57-69.e9. [PMID: 31519522 PMCID: PMC6863433 DOI: 10.1016/j.molcel.2019.07.037] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 05/28/2019] [Accepted: 07/26/2019] [Indexed: 01/08/2023]
Abstract
Although correlations between RNA polymerase II (RNAPII) transcription stress, R-loops, and genome instability have been established, the mechanisms underlying these connections remain poorly understood. Here, we used a mutant version of the transcription elongation factor TFIIS (TFIISmut), aiming to specifically induce increased levels of RNAPII pausing, arrest, and/or backtracking in human cells. Indeed, TFIISmut expression results in slower elongation rates, relative depletion of polymerases from the end of genes, and increased levels of stopped RNAPII; it affects mRNA splicing and termination as well. Remarkably, TFIISmut expression also dramatically increases R-loops, which may form at the anterior end of backtracked RNAPII and trigger genome instability, including DNA strand breaks. These results shed light on the relationship between transcription stress and R-loops and suggest that different classes of R-loops may exist, potentially with distinct consequences for genome stability.
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Affiliation(s)
- Diana Zatreanu
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Zhong Han
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Richard Mitter
- Bioinformatics and Biostatistics Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Emanuela Tumini
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Universidad de Sevilla, Seville, Spain
| | - Hannah Williams
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Lea Gregersen
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - A Barbara Dirac-Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Stefania Roma
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Universidad de Sevilla, Seville, Spain
| | - Aengus Stewart
- Bioinformatics and Biostatistics Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Andres Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Universidad de Sevilla, Seville, Spain
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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4
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Bradley CC, Gordon AJE, Halliday JA, Herman C. Transcription fidelity: New paradigms in epigenetic inheritance, genome instability and disease. DNA Repair (Amst) 2019; 81:102652. [PMID: 31326363 DOI: 10.1016/j.dnarep.2019.102652] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RNA transcription errors are transient, yet frequent, events that do have consequences for the cell. However, until recently we lacked the tools to empirically measure and study these errors. Advances in RNA library preparation and next generation sequencing (NGS) have allowed the spectrum of transcription errors to be empirically measured over the entire transcriptome and in nascent transcripts. Combining these powerful methods with forward and reverse genetic strategies has refined our understanding of transcription factors known to enhance RNA accuracy and will enable the discovery of new candidates. Furthermore, these approaches will shed additional light on the complex interplay between transcription fidelity and other DNA transactions, such as replication and repair, and explore a role for transcription errors in cellular evolution and disease.
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Affiliation(s)
- Catherine C Bradley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA; Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, 77030, USA; Robert and Janice McNair Foundation/ McNair Medical Institute M.D./Ph.D. Scholars Program, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, 77030, USA.
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5
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Huang XY, Sun WY, Yan ZQ, Shi HR, Yang QL, Wang PF, Li SG, Liu LX, Zhao SG, Gun SB. Novel Insights reveal Anti-microbial Gene Regulation of Piglet Intestine Immune in response to Clostridium perfringens Infection. Sci Rep 2019; 9:1963. [PMID: 30760749 PMCID: PMC6374412 DOI: 10.1038/s41598-018-37898-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 12/17/2018] [Indexed: 12/16/2022] Open
Abstract
LncRNA play important roles in regulation of host immune and inflammation responses in defending bacterial infection. Clostridium perfringens (C. perfringens) type C is one of primary bacteria leading to piglet diarrhea and other intestinal inflammatory diseases. For the differences of host immune capacity, individuals usually show resistance and susceptibility to bacterial infection. However, whether and how lncRNAs involved in modulating host immune resistance have not been reported. We have investigated the expression patterns of ileum lncRNAs of 7-day-old piglets infected by C. perfringens type C through RNA sequencing. A total of 16 lncRNAs and 126 mRNAs were significantly differentially expressed in resistance (IR) and susceptibility (IS) groups. Many lncRNAs and mRNAs were identified to regulate resistance and susceptibility of piglets through immune related pathways. Five lncRNAs may have potential function on regulating the expressions of cytokines, these lncRNAs and cytokines work together to co-regulated piglet immune response to C. perfringens, affecting host resistance and susceptibility. These results provide valuable information for understanding the functions of lncRNA and mRNA in affecting piglet diarrhea resistance of defensing to C. perfringens type C, these lncRNAs and mRNAs may be used as the important biomarkers for decreasing C. perfringens spread and diseases in human and piglets.
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Affiliation(s)
- Xiao Yu Huang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Wen Yang Sun
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Zun Qiang Yan
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Hai Ren Shi
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Qiao Li Yang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Peng Fei Wang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Sheng Gui Li
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Li Xia Liu
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou, 730030, China
| | - Sheng Guo Zhao
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Shuang Bao Gun
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China.
- Gansu Research Center for Swine Production Engineering and Technology, Lanzhou, 730070, China.
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6
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Majerska J, Feretzaki M, Glousker G, Lingner J. Transformation-induced stress at telomeres is counteracted through changes in the telomeric proteome including SAMHD1. Life Sci Alliance 2018; 1:e201800121. [PMID: 30456372 PMCID: PMC6238619 DOI: 10.26508/lsa.201800121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 12/13/2022] Open
Abstract
The authors apply telomeric chromatin analysis to identify factors that accumulate at telomeres during cellular transformation, promoting telomere replication and repair and counteracting oncogene-borne telomere replication stress. Telomeres play crucial roles during tumorigenesis, inducing cellular senescence upon telomere shortening and extensive chromosome instability during telomere crisis. However, it has not been investigated if and how cellular transformation and oncogenic stress alter telomeric chromatin composition and function. Here, we transform human fibroblasts by consecutive transduction with vectors expressing hTERT, the SV40 early region, and activated H-RasV12. Pairwise comparisons of the telomeric proteome during different stages of transformation reveal up-regulation of proteins involved in chromatin remodeling, DNA repair, and replication at chromosome ends. Depletion of several of these proteins induces telomere fragility, indicating their roles in replication of telomeric DNA. Depletion of SAMHD1, which has reported roles in DNA resection and homology-directed repair, leads to telomere breakage events in cells deprived of the shelterin component TRF1. Thus, our analysis identifies factors, which accumulate at telomeres during cellular transformation to promote telomere replication and repair, resisting oncogene-borne telomere replication stress.
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Affiliation(s)
- Jana Majerska
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Swiss Institute for Experimental Cancer Research, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marianna Feretzaki
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Swiss Institute for Experimental Cancer Research, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Galina Glousker
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Swiss Institute for Experimental Cancer Research, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Joachim Lingner
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Swiss Institute for Experimental Cancer Research, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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7
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TCEA1 regulates the proliferative potential of mouse myeloid cells. Exp Cell Res 2018; 370:551-560. [PMID: 30009791 DOI: 10.1016/j.yexcr.2018.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 01/15/2023]
Abstract
Leukemia is a malignance with complex pathogenesis and poor prognosis. Discovery of noval regulators amenable to leukemia could be of value to gain insight into the pathogenesis, diagnosis and prognosis of leukemia. Here, we conducted a large-scale shRNA library screening for functional regulators in the development of myeloid cells in primary cells. We identified eighteen candidate regulators in the primary screening. Those genes cover a wide range of cellular functions, including gene expression regulation, intracellular signaling transduction, nucleotide excision repair, cell cycle control and transcription regulation. In both primary screening and validation, shRNAs targeting Tcea1, encoding the transcription elongation factor A (SII) 1, exhibited the greatest influence on the proliferative potential of cells. Knocking down the expression of Tcea1 in the 32Dcl3 myeloid cell line led to enhanced proliferation of myeloid cells and blockage of myeloid differentiation induced by G-CSF. In addition, silence of Tcea1 inhibited apoptosis of myeloid cells. Thus, Tcea1 was identified as a gene which can influence the proliferative potential, survival and differentiation of myeloid cells. These findings have implications for how transcriptional elongation influences myeloid cell development and leukemic transformation.
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8
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Unarta IC, Zhu L, Tse CKM, Cheung PPH, Yu J, Huang X. Molecular mechanisms of RNA polymerase II transcription elongation elucidated by kinetic network models. Curr Opin Struct Biol 2018; 49:54-62. [PMID: 29414512 DOI: 10.1016/j.sbi.2018.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 12/30/2022]
Abstract
Transcription elongation cycle (TEC) of RNA polymerase II (Pol II) is a process of adding a nucleoside triphosphate to the growing messenger RNA chain. Due to the long timescale events in Pol II TEC, an advanced computational technique, such as Markov State Model (MSM), is needed to provide atomistic mechanism and reaction rates. The combination of MSM and experimental results can be used to build a kinetic network model (KNM) of the whole TEC. This review provides a brief protocol to build MSM and KNM of the whole TEC, along with the latest findings of MSM and other computational studies of Pol II TEC. Lastly, we offer a perspective on potentially using a sequence dependent KNM to predict genome-wide transcription error.
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Affiliation(s)
- Ilona Christy Unarta
- Bioengineering Graduate Program, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong
| | - Lizhe Zhu
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Carmen Ka Man Tse
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Peter Pak-Hang Cheung
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong
| | - Jin Yu
- Beijing Computational Science Research Center, Beijing 100084, China
| | - Xuhui Huang
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.
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9
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Reid-Bayliss KS, Loeb LA. Accurate RNA consensus sequencing for high-fidelity detection of transcriptional mutagenesis-induced epimutations. Proc Natl Acad Sci U S A 2017; 114:9415-9420. [PMID: 28798064 PMCID: PMC5584456 DOI: 10.1073/pnas.1709166114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transcriptional mutagenesis (TM) due to misincorporation during RNA transcription can result in mutant RNAs, or epimutations, that generate proteins with altered properties. TM has long been hypothesized to play a role in aging, cancer, and viral and bacterial evolution. However, inadequate methodologies have limited progress in elucidating a causal association. We present a high-throughput, highly accurate RNA sequencing method to measure epimutations with single-molecule sensitivity. Accurate RNA consensus sequencing (ARC-seq) uniquely combines RNA barcoding and generation of multiple cDNA copies per RNA molecule to eliminate errors introduced during cDNA synthesis, PCR, and sequencing. The stringency of ARC-seq can be scaled to accommodate the quality of input RNAs. We apply ARC-seq to directly assess transcriptome-wide epimutations resulting from RNA polymerase mutants and oxidative stress.
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Affiliation(s)
- Kate S Reid-Bayliss
- Department of Pathology, University of Washington School of Medicine, Seattle, WA 98195
| | - Lawrence A Loeb
- Department of Pathology, University of Washington School of Medicine, Seattle, WA 98195;
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195
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10
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Mechanism of DNA alkylation-induced transcriptional stalling, lesion bypass, and mutagenesis. Proc Natl Acad Sci U S A 2017; 114:E7082-E7091. [PMID: 28784758 DOI: 10.1073/pnas.1708748114] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alkylated DNA lesions, induced by both exogenous chemical agents and endogenous metabolites, interfere with the efficiency and accuracy of DNA replication and transcription. However, the molecular mechanisms of DNA alkylation-induced transcriptional stalling and mutagenesis remain unknown. In this study, we systematically investigated how RNA polymerase II (pol II) recognizes and bypasses regioisomeric O2-, N3-, and O4-ethylthymidine (O2-, N3-, and O4-EtdT) lesions. We observed distinct pol II stalling profiles for the three regioisomeric EtdT lesions. Intriguingly, pol II stalling at O2-EtdT and N3-EtdT sites is exacerbated by TFIIS-stimulated proofreading activity. Assessment for the impact of the EtdT lesions on individual fidelity checkpoints provided further mechanistic insights, where the transcriptional lesion bypass routes for the three EtdT lesions are controlled by distinct fidelity checkpoints. The error-free transcriptional lesion bypass route is strongly favored for the minor-groove O2-EtdT lesion. In contrast, a dominant error-prone route stemming from GMP misincorporation was observed for the major-groove O4-EtdT lesion. For the N3-EtdT lesion that disrupts base pairing, multiple transcriptional lesion bypass routes were found. Importantly, the results from the present in vitro transcriptional studies are well correlated with in vivo transcriptional mutagenesis analysis. Finally, we identified a minor-groove-sensing motif from pol II (termed Pro-Gate loop). The Pro-Gate loop faces toward the minor groove of RNA:DNA hybrid and is involved in modulating the translocation of minor-groove alkylated DNA template after nucleotide incorporation opposite the lesion. Taken together, this work provides important mechanistic insights into transcriptional stalling, lesion bypass, and mutagenesis of alkylated DNA lesions.
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11
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Hu R, Wei P, Jin L, Zheng T, Chen WY, Liu XY, Shi XD, Hao JR, Sun N, Gao C. Overexpression of EphB2 in hippocampus rescues impaired NMDA receptors trafficking and cognitive dysfunction in Alzheimer model. Cell Death Dis 2017; 8:e2717. [PMID: 28358367 PMCID: PMC5386541 DOI: 10.1038/cddis.2017.140] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease, which affects more and more people. But there is still no effective treatment for preventing or reversing the progression of the disease. Soluble amyloid-beta (Aβ) oligomers, also known as Aβ-derived diffusible ligands (ADDLs) play an important role in AD. Synaptic activity and cognition critically depend on the function of glutamate receptors. Targeting N-methyl-D-aspartic acid (NMDA) receptors trafficking and its regulation is a new strategy for AD early treatment. EphB2 is a key regulator of synaptic localization of NMDA receptors. Aβ oligomers could bind to the fibronectin repeats domain of EphB2 and trigger EphB2 degradation in the proteasome. Here we identified that overexpression of EphB2 with lentiviral vectors in dorsal hippocampus improved impaired memory deficits and anxiety or depression-like behaviors in APPswe/PS1-dE9 (APP/PS1) transgenic mice. Phosphorylation and surface expression of GluN2B-containing NMDA receptors were also improved. Overexpression of EphB2 also rescued the ADDLs-induced depletion of the expression of EphB2 and GluN2B-containing NMDA receptors trafficking in cultured hippocampal neurons. These results suggest that improving the decreased expression of EphB2 and subsequent GluN2B-containing NMDA receptors trafficking in hippocampus may be a promising strategy for AD treatment.
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Affiliation(s)
- Rui Hu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Department of Anesthesiology, Xuzhou TCM Hospital, Xuzhou, Jiangsu 221009, China
| | - Pan Wei
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Lu Jin
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Teng Zheng
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Wen-Yu Chen
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Xiao-Ya Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Xiao-Dong Shi
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Jing-Ru Hao
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Nan Sun
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Can Gao
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
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12
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Ostasiewicz B, Ostasiewicz P, Duś-Szachniewicz K, Ostasiewicz K, Ziółkowski P. Quantitative analysis of gene expression in fixed colorectal carcinoma samples as a method for biomarker validation. Mol Med Rep 2016; 13:5084-92. [PMID: 27121919 PMCID: PMC4878534 DOI: 10.3892/mmr.2016.5200] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 03/09/2016] [Indexed: 02/06/2023] Open
Abstract
Biomarkers have been described as the future of oncology. Modern proteomics provide an invaluable tool for the near-whole proteome screening for proteins expressed differently in neoplastic vs. healthy tissues. However, in order to select the most promising biomarkers, an independent method of validation is required. The aim of the current study was to propose a methodology for the validation of biomarkers. Due to material availability the majority of large scale biomarker studies are performed using formalin-fixed paraffin-embedded (FFPE) tissues, therefore these were selected for use in the current study. A total of 10 genes were selected from what have been previously described as the most promising candidate biomarkers, and the expression levels were analyzed with reverse transcription-quantitative polymerase chain reaction (RT-qPCR) using calibrator normalized relative quantification with the efficiency correction. For 6/10 analyzed genes, the results were consistent with the proteomic data; for the remaining four genes, the results were inconclusive. The upregulation of karyopherin α 2 (KPNA2) and chromosome segregation 1-like (CSE1L) in colorectal carcinoma, in addition to downregulation of chloride channel accessory 1 (CLCA1), fatty acid binding protein 1 (FABP1), sodium channel, voltage gated, type VII α subunit (SCN7A) and solute carrier family 26 (anion exchanger), member 3 (SLC26A3) was confirmed. With the combined use of proteomic and genetic tools, it was reported, for the first time to the best of our knowledge, that SCN7A was downregulated in colorectal carcinoma at mRNA and protein levels. It had been previously suggested that the remaining five genes served an important role in colorectal carcinogenesis, however the current study provided strong evidence to support their use as biomarkers. Thus, it was concluded that combination of RT-qPCR with proteomics offers a powerful methodology for biomarker identification, which can be used to analyze FFPE samples.
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Affiliation(s)
- Beata Ostasiewicz
- Department of Pathology, Wrocław Medical University, Wrocław 50‑368, Poland
| | - Paweł Ostasiewicz
- Department of Pathology, Wrocław Medical University, Wrocław 50‑368, Poland
| | | | | | - Piotr Ziółkowski
- Department of Pathology, Wrocław Medical University, Wrocław 50‑368, Poland
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13
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Liao JM, Cao B, Deng J, Zhou X, Strong M, Zeng S, Xiong J, Flemington E, Lu H. TFIIS.h, a new target of p53, regulates transcription efficiency of pro-apoptotic bax gene. Sci Rep 2016; 6:23542. [PMID: 27005522 PMCID: PMC4804275 DOI: 10.1038/srep23542] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 03/03/2016] [Indexed: 11/09/2022] Open
Abstract
Tumor suppressor p53 transcriptionally regulates hundreds of genes involved in various cellular functions. However, the detailed mechanisms underlying the selection of p53 targets in response to different stresses are still elusive. Here, we identify TFIIS.h, a transcription elongation factor, as a new transcriptional target of p53, and also show that it can enhance the efficiency of transcription elongation of apoptosis-associated bax gene, but not cell cycle-associated p21 (CDKN1A) gene. TFIIS.h is revealed as a p53 target through microarray analysis of RNAs extracted from cells treated with or without inauhzin (INZ), a p53 activator, and further confirmed by RT-q-PCR, western blot, luciferase reporter, and ChIP assays. Interestingly, knocking down TFIIS.h impairs, but overexpressing TFIIS.h promotes, induction of bax, but not other p53 targets including p21, by p53 activation. In addition, overexpression of TFIIS.h induces cell death in a bax- dependent fashion. These findings reveal a mechanism by which p53 utilizes TFIIS.h to selectively promote the transcriptional elongation of the bax gene, upsurging cell death in response to severe DNA damage.
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Affiliation(s)
- Jun-Ming Liao
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Bo Cao
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Jun Deng
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA.,Department of Oncology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, PR China
| | - Xiang Zhou
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Michael Strong
- Department of Pathology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Shelya Zeng
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Jianping Xiong
- Department of Oncology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, PR China
| | - Erik Flemington
- Department of Pathology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Hua Lu
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
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14
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Li J, Jin Y, Pan S, Chen Y, Wang K, Lin C, Jin S, Wu J. TCEA3 Attenuates Gastric Cancer Growth by Apoptosis Induction. Med Sci Monit 2015; 21:3241-6. [PMID: 26498664 PMCID: PMC4627366 DOI: 10.12659/msm.895860] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Background The aim of this study was to investigate and interpret the expression level and potential function of TCEA3 in gastric cancer. Material/Methods qRT-PCR was used to determine the expression level of TCEA3 in gastric cancer tissues. Pearson χ2 test was performed to clarify the correlation between TCEA3 expression and patients’ clinicopathologic characteristics. Biological function of TCEA3 was tested by proliferation assay and colony formation assay. Flow cytometry was used to study the potential function of TCEA3 in apoptosis induction. Results TCEA3 expression was significantly downregulated in gastric cancer tissues compared with paired normal tissues. Poor prognoses were observed in the low TCEA3 expression group of patients in contrast to the high TCEA3 expression group. Functionally, upregulation of TCEA3 inhibited gastric cancer cell proliferation and colony formation. We also found that TCEA3 may attenuate cell growth through apoptosis induction. Conclusions Our findings suggest that TCEA3 attenuates the proliferation and induces apoptosis of gastric cancer cells.
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Affiliation(s)
- Jia Li
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Yin Jin
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Shuang Pan
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Yina Chen
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Kaijing Wang
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Chunjing Lin
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Shuqing Jin
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
| | - Jiansheng Wu
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China (mainland)
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15
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Peng J, Ma J, Li W, Mo R, Zhang P, Gao K, Jin X, Xiao J, Wang C, Fan J. Stabilization of MCRS1 by BAP1 prevents chromosome instability in renal cell carcinoma. Cancer Lett 2015; 369:167-74. [PMID: 26300492 DOI: 10.1016/j.canlet.2015.08.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/17/2015] [Accepted: 08/17/2015] [Indexed: 01/21/2023]
Abstract
Characterization of the exome and genome of carcinoma (ccRCC) by next-generation sequencing identified numerous genetic alternations. BRCA1-associated protein-1 (BAP1) was identified as one of the most frequently mutated genes in ccRCC, suggesting that BAP1 is a potential key driver for ccRCC cancer initiation and progression. However, how BAP1 mutations contribute to ccRCC remains to be elucidated. BAP1 is a nuclear de-ubiquitinating enzyme and cleaves the ubiquitin chain from the substrates. Here, we identified MCRS1 as a bona fide substrate for BAP1. MCRS1 is a component of the centrosome proteins, and plays an essential role in spindle assembly. BAP1 binds to MCRS1 and stabilizes MCRS1 by de-ubiquitination. BAP1 contributes to chromosome stability partially via MCRS1. A positive correlation was identified between BAP1 and MCRS1 expression in ccRCC tissues. Both BAP1 loss and MCRS1 down-regulation in ccRCC were associated with adverse clinicopathological features. This study revealed a novel mechanism for BAP1 involved in MCRS1 stability regulation, and provided insight in understanding the relationship between BAP1 mutations and chromosome instability in ccRCC.
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Affiliation(s)
- Jingtao Peng
- Department of Urology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, China
| | - Jian Ma
- Department of Urology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, China
| | - Weiguo Li
- Department of Urology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, China
| | - Ren Mo
- Department of Urology, Inner Mongolia Autonomous Region Peoples Hospital, 20 Zhaowuda Road, Hohhot 010017, China
| | - Pingzhao Zhang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, China
| | - Kun Gao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, China
| | - Xiaofeng Jin
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, China
| | - Jiantao Xiao
- Department of Urology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, China
| | - Chenji Wang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, China.
| | - Jie Fan
- Department of Urology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, China.
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16
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Imashimizu M, Takahashi H, Oshima T, McIntosh C, Bubunenko M, Court DL, Kashlev M. Visualizing translocation dynamics and nascent transcript errors in paused RNA polymerases in vivo. Genome Biol 2015; 16:98. [PMID: 25976475 PMCID: PMC4457086 DOI: 10.1186/s13059-015-0666-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/05/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Transcription elongation is frequently interrupted by pausing signals in DNA, with downstream effects on gene expression. Transcription errors also induce prolonged pausing, which can lead to a destabilized genome by interfering with DNA replication. Mechanisms of pausing associated with translocation blocks and misincorporation have been characterized in vitro, but not in vivo. RESULTS We investigate the pausing pattern of RNA polymerase (RNAP) in Escherichia coli by a novel approach, combining native elongating transcript sequencing (NET-seq) with RNase footprinting of the transcripts (RNET-seq). We reveal that the G-dC base pair at the 5' end of the RNA-DNA hybrid interferes with RNAP translocation. The distance between the 5' G-dC base pair and the 3' end of RNA fluctuates over a three-nucleotide width. Thus, the G-dC base pair can induce pausing in post-translocated, pre-translocated, and backtracked states of RNAP. Additionally, a CpG sequence of the template DNA strand spanning the active site of RNAP inhibits elongation and induces G-to-A errors, which leads to backtracking of RNAP. Gre factors efficiently proofread the errors and rescue the backtracked complexes. We also find that pausing events are enriched in the 5' untranslated region and antisense transcription of mRNA genes and are reduced in rRNA genes. CONCLUSIONS In E. coli, robust transcriptional pausing involves RNAP interaction with G-dC at the upstream end of the RNA-DNA hybrid, which interferes with translocation. CpG DNA sequences induce transcriptional pausing and G-to-A errors.
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Affiliation(s)
- Masahiko Imashimizu
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan.
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Ikoma, Nara, 630-0192, Japan.
| | - Carl McIntosh
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Mikhail Bubunenko
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Donald L Court
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Mikhail Kashlev
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
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17
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Wang R, Liao S, Fan K, Zhang J, Tu X. ¹H, ¹³C and ¹⁵N resonance assignments of TFIIS2-1 PWWP domain from Trypanosoma brucei. BIOMOLECULAR NMR ASSIGNMENTS 2013; 7:275-277. [PMID: 22987229 DOI: 10.1007/s12104-012-9426-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 09/10/2012] [Indexed: 06/01/2023]
Abstract
TFIIS2-1, one of the two trypanosome homologues of transcription elongation factor TFIIS (TbTFIIS1, TbTFIIS2-1), with a PWWP domain in the N-terminus, has a possible association with the largest subunit of RNA polymerase II (RPB1) and shares an essential function with TbTFIIS1 in the growth of Trypanosoma brucei. Here we report the resonance assignments of the protein backbone of the PWWP domain of TFIIS2-1 from T. brucei.
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Affiliation(s)
- Rui Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230026, Anhui, People's Republic of China
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18
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Imashimizu M, Oshima T, Lubkowska L, Kashlev M. Direct assessment of transcription fidelity by high-resolution RNA sequencing. Nucleic Acids Res 2013; 41:9090-104. [PMID: 23925128 PMCID: PMC3799451 DOI: 10.1093/nar/gkt698] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cancerous and aging cells have long been thought to be impacted by transcription errors that cause genetic and epigenetic changes. Until now, a lack of methodology for directly assessing such errors hindered evaluation of their impact to the cells. We report a high-resolution Illumina RNA-seq method that can assess noncoded base substitutions in mRNA at 10−4–10−5 per base frequencies in vitro and in vivo. Statistically reliable detection of changes in transcription fidelity through ∼103 nt DNA sites assures that the RNA-seq can analyze the fidelity in a large number of the sites where errors occur. A combination of the RNA-seq and biochemical analyses of the positions for the errors revealed two sequence-specific mechanisms that increase transcription fidelity by Escherichia coli RNA polymerase: (i) enhanced suppression of nucleotide misincorporation that improves selectivity for the cognate substrate, and (ii) increased backtracking of the RNA polymerase that decreases a chance of error propagation to the full-length transcript after misincorporation and provides an opportunity to proofread the error. This method is adoptable to a genome-wide assessment of transcription fidelity.
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Affiliation(s)
- Masahiko Imashimizu
- Gene Regulation and Chromosome Biology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA and Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara 630-0192, Japan
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19
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Bywater MJ, Pearson RB, McArthur GA, Hannan RD. Dysregulation of the basal RNA polymerase transcription apparatus in cancer. Nat Rev Cancer 2013; 13:299-314. [PMID: 23612459 DOI: 10.1038/nrc3496] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mutations that directly affect transcription by RNA polymerases rank among the most central mediators of malignant transformation, but the frequency of new anticancer drugs that selectively target defective transcription apparatus entering the clinic has been limited. This is because targeting the large protein-protein and protein-DNA interfaces that control both generic and selective aspects of RNA polymerase transcription has proved extremely difficult. However, recent technological advances have led to a 'quantum leap' in our comprehension of the structure and function of the core RNA polymerase components, how they are dysregulated in a broad range of cancers and how they may be targeted for 'transcription therapy'.
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Affiliation(s)
- Megan J Bywater
- Division of Cancer Research, Peter MacCallum Cancer Centre, Melbourne 8006, Victoria, Australia
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20
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Cha Y, Kim DK, Hyun J, Kim SJ, Park KS. TCEA3 binds to TGF-beta receptor I and induces Smad-independent, JNK-dependent apoptosis in ovarian cancer cells. Cell Signal 2013; 25:1245-51. [PMID: 23357533 DOI: 10.1016/j.cellsig.2013.01.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 12/31/2012] [Accepted: 01/21/2013] [Indexed: 12/21/2022]
Abstract
TFIIS is a transcription elongation factor conserved in frog, mouse and human. Recently, knockdown of TCEA1, the most well-characterized isoform of TFIIS, by RNA silencing was reported to inhibit cancer cell proliferation and induce apoptosis in breast, lung and pancreatic cancer cell lines through activation of p53 (Hubbard et al., 2008 [1]). However, the functions of other TFIIS isoforms are poorly defined. The present study shows that TCEA3, an isoform of TFIIS, can trigger ovarian cancer-specific cell death by activating the JNK signaling pathway. TCEA3 expression is low in ovarian cancer cell lines compared to noncancerous ovarian epithelial cells. Suppression of TCEA3 in noncancerous ovarian epithelial cells promotes cell growth whereas ectopic expression of TCEA3 in ovarian cancer cell lines induces the caspase-dependent mitochondrial cell death pathway. Molecular and chemical inhibition assays show that the interaction of TCEA3 with TGFβ receptor I induces cell death in ovarian cancer cell through Smad-independent activation of the JNK pathway. These results reveal that TCEA3 induces a novel apoptotic mechanism in OEC, which provides TCEA3 as a novel target to develop therapeutics of ovarian cancer.
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Affiliation(s)
- Young Cha
- Department of Biomedical Science, College of Life Science, CHA University, Seoul, Republic of Korea
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21
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Li XH, Fang DN, Zeng CM. Knockdown of MED19 by short hairpin RNA-mediated gene silencing inhibits pancreatic cancer cell proliferation. Cancer Biother Radiopharm 2012; 26:495-501. [PMID: 21834715 DOI: 10.1089/cbr.2010.0863] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abnormal gene transcription plays an important role in oncogenesis. In cancer cells, the improper activation of specific genes is usually ascribed to aberrant transcription machinery including transcription factors, RNA polymerase II, and Mediator complex. This study reports on short hairpin RNA (shRNA)-mediated gene silencing of MED19, a subunit of Mediator complex, and its effect on the growth of pancreatic cancer cells. RNA interference was performed by lentivirus shRNA system to specifically knockdown MED19 expression in Aspc-1 and Panc-1 cells. The knockdown efficiency of MED19 was confirmed by quantitative RT-PCR and western blot. The effect of MED19 shRNA on Aspc-1 and Panc-1 cell proliferation was evaluated by methylthiazoletetrazolium assay, BrdU incorporation assay, colony formation assay, and flow cytometry assay. This study shows that downregulation of MED19 remarkably reduced cancer cell proliferation and colony formation capacity in two pancreatic cancer cell lines. In addition, downregulated MED19 induced G1-phase cell cycle arrest and apoptosis. This study provides a potent role of MED19 in promoting pancreatic cancer growth and a possible drug target for cancer therapy.
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Affiliation(s)
- Xing-Hua Li
- Department of Digestion Medicine, Shanghai Eighth People's Hospital, No. 8 Caobao Road, Shanghai, China.
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22
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A novel system for rapid screening of effective siRNA target sites by one step transfection with a single vector. J Biotechnol 2011; 155:135-9. [DOI: 10.1016/j.jbiotec.2011.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 05/02/2011] [Accepted: 05/07/2011] [Indexed: 01/28/2023]
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23
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RNF20 inhibits TFIIS-facilitated transcriptional elongation to suppress pro-oncogenic gene expression. Mol Cell 2011; 42:477-88. [PMID: 21596312 DOI: 10.1016/j.molcel.2011.03.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/27/2011] [Accepted: 03/14/2011] [Indexed: 12/31/2022]
Abstract
hBRE1/RNF20 is the major E3 ubiquitin ligase for histone H2B. RNF20 depletion causes a global reduction of monoubiquitylated H2B (H2Bub) levels and augments the expression of growth-promoting, pro-oncogenic genes. Those genes reside preferentially in compact chromatin and are inefficiently transcribed under basal conditions. We now report that RNF20, presumably via H2Bub, selectively represses those genes by interfering with chromatin recruitment of TFIIS, a factor capable of relieving stalled RNA polymerase II. RNF20 inhibits the interaction between TFIIS and the PAF1 complex and hinders transcriptional elongation. TFIIS ablation selectively abolishes the upregulation of those genes upon RNF20 depletion and attenuates the cellular response to EGF. Consistent with its positive role in transcription of pro-oncogenic genes, TFIIS expression is elevated in various human tumors. Our findings provide a molecular mechanism for selective gene repression by RNF20 and position TFIIS as a key target of RNF20's tumor suppressor activity.
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Shiloh Y, Shema E, Moyal L, Oren M. RNF20-RNF40: A ubiquitin-driven link between gene expression and the DNA damage response. FEBS Lett 2011; 585:2795-802. [PMID: 21827756 DOI: 10.1016/j.febslet.2011.07.034] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 07/25/2011] [Accepted: 07/25/2011] [Indexed: 10/17/2022]
Abstract
The DNA damage response (DDR) is emerging as a vast signaling network that temporarily modulates numerous aspects of cellular metabolism in the face of DNA lesions, especially critical ones such as the double strand break (DSB). The DDR involves extensive dynamics of protein post-translational modifications, most notably phosphorylation and ubiquitylation. The DSB response is mobilized primarily by the ATM protein kinase, which phosphorylates a plethora of key players in its various branches. It is based on a core of proteins dedicated to the damage response, and a cadre of proteins borrowed temporarily from other cellular processes to help meet the challenge. A recently identified novel component of the DDR pathway - histone H2B monoubiquitylation - exemplifies this principle. In mammalian cells, H2B monoubiquitylation is driven primarily by an E3 ubiquitin ligase composed of the two RING finger proteins RNF20 and RNF40. Generation of monoubiquitylated histone H2B (H2Bub) has been known to be coupled to gene transcription, presumably modulating chromatin decondensation at transcribed regions. New evidence indicates that the regulatory function of H2Bub on gene expression can selectively enhance or suppress the expression of distinct subsets of genes through a mechanism involving the hPAF1 complex and the TFIIS protein. This delicate regulatory process specifically affects genes that control cell growth and genome stability, and places RNF20 and RNF40 in the realm of tumor suppressor proteins. In parallel, it was found that following DSB induction, the H2B monoubiquitylation module is recruited to damage sites where it induces local H2Bub, which in turn is required for timely recruitment of DSB repair protein and, subsequently, timely DSB repair. This pathway represents a crossroads of the DDR and chromatin organization, and is a typical example of how the DDR calls to action functional modules that in unprovoked cells regulate other processes.
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Affiliation(s)
- Yosef Shiloh
- The David and Inez Myers Laboratory for Cancer Genetics, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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25
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The TFIIS and TFIIS-like genes from Medicago truncatula are involved in oxidative stress response. Gene 2011; 470:20-30. [DOI: 10.1016/j.gene.2010.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 07/26/2010] [Accepted: 09/07/2010] [Indexed: 01/15/2023]
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26
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Jensen A, Mullenders LHF. Transcription factor IIS impacts UV-inhibited transcription. DNA Repair (Amst) 2010; 9:1142-50. [PMID: 20729154 DOI: 10.1016/j.dnarep.2010.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 07/08/2010] [Accepted: 08/03/2010] [Indexed: 11/25/2022]
Abstract
Inhibition of transcription elongation can cause severe developmental and neurological abnormalities notably manifested by the rare recessive progeroid disorder Cockayne syndrome (CS). DNA alterations can cause permanent blocks to an elongating RNA polymerase II (RNAPII) leading to transcriptional arrest. Abrogation of transcription arrest requires removal of transcription blocking lesions through transcription-coupled nucleotide excision repair (TC-NER) a process defective in CS. Transcription elongation factor IIS (TFIIS) has been found to localize with the TC-NER complex after cellular exposure to UV-C light and in vitro addition of TFIIS to a damage arrested RNAPII causes transcript shortening. Hence default TFIIS activity might mimic or contribute to the severe phenotype of Cockayne syndrome. Here we show that down regulation of TFIIS by siRNA treatment of human cells lead to impaired RNA synthesis recovery and elevated levels of hyper-phosphorylated RNAPII after UV-irradiation. TFIIS knock down does not affect TC-NER, the reappearance of hypo-phosphorylated RNAPII post-UV-irradiation, UV sensitivity or the p53 damage response. These findings reveal a role for TFIIS in transcription recovery and re-establishment of the balance between hypo- and hyper-phosphorylated RNAPII after DNA damage repair.
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Affiliation(s)
- Anne Jensen
- Department of Toxicogenetics, Leiden University Medical Center, The Netherlands
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27
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Wilson R, Purcell D, Netter HJ, Revill PA. Does RNA interference provide new hope for control of chronic hepatitis B infection? Antivir Ther 2010; 14:879-89. [PMID: 19918092 DOI: 10.3851/imp1424] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hepatitis B virus (HBV) infection is a global human health problem, with an estimated 350 million people having chronic hepatitis B (CHB) infection worldwide. The majority of infections acquired during adulthood are resolved without intervention; however, infections acquired at birth or during early childhood have a 90% chance of progressing to CHB, leading to a host of adverse effects on the liver, including cirrhosis and cancer. CHB is currently treated with a combination of cytokines and/or nucleoside/nucleotide analogues; however, adverse side effects to cytokine therapy and the selection of resistance mutations to nucleoside analogues often abrogate the efficacy of treatment. The recent discovery that small interfering RNA and microRNA are active in mammalian cells suggests it might be possible to supplement existing HBV therapies with small RNA-based therapeutic(s).
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Affiliation(s)
- Rachel Wilson
- Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria, Australia
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Grasser M, Kane CM, Merkle T, Melzer M, Emmersen J, Grasser KD. Transcript elongation factor TFIIS is involved in arabidopsis seed dormancy. J Mol Biol 2009; 386:598-611. [PMID: 19150360 DOI: 10.1016/j.jmb.2008.12.066] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 12/13/2008] [Accepted: 12/22/2008] [Indexed: 01/12/2023]
Abstract
Transcript elongation factor TFIIS promotes efficient transcription by RNA polymerase II, since it assists in bypassing blocks during mRNA synthesis. While yeast cells lacking TFIIS are viable, inactivation of mouse TFIIS causes embryonic lethality. Here, we have identified a protein encoded in the Arabidopsis genome that displays a marked sequence similarity to TFIIS of other organisms, primarily within domains II and III in the C-terminal part of the protein. TFIIS is widely expressed in Arabidopsis, and a green fluorescent protein-TFIIS fusion protein localises specifically to the cell nucleus. When expressed in yeast cells lacking the endogenous TFIIS, Arabidopsis TFIIS partially complements the sensitivity of mutant cells to the nucleotide analog 6-azauridine, which is a typical characteristic of transcript elongation factors. We have characterised Arabidopsis lines harbouring T-DNA insertions in the coding sequence of TFIIS. Plants homozygous for T-DNA insertions are viable, and genomewide transcript profiling revealed that compared to control plants, a relatively small number of genes are differentially expressed in mutant plants. TFIIS(-/-) plants display essentially normal development, but they flower slightly earlier than control plants and show clearly reduced seed dormancy. Plants with RNAi-mediated knockdown of TFIIS expression also are affected in seed dormancy. Therefore, TFIIS plays a critical role in Arabidopsis seed development.
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Affiliation(s)
- Marion Grasser
- Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark
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