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Wang J, Chen Q, Wang X, Zhao S, Deng H, Guo B, Zhang C, Song X, Deng W, Zhang T, Ni H. TFIIB-related factor 1 is a nucleolar protein that promotes RNA polymerase I-directed transcription and tumour cell growth. Hum Mol Genet 2023; 32:104-121. [PMID: 35925837 DOI: 10.1093/hmg/ddac152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 06/26/2022] [Accepted: 07/01/2022] [Indexed: 01/25/2023] Open
Abstract
Eukaryotic RNA polymerase I (Pol I) products play fundamental roles in ribosomal assembly, protein synthesis, metabolism and cell growth. Abnormal expression of both Pol I transcription-related factors and Pol I products causes a range of diseases, including ribosomopathies and cancers. However, the factors and mechanisms governing Pol I-dependent transcription remain to be elucidated. Here, we report that transcription factor IIB-related factor 1 (BRF1), a subunit of transcription factor IIIB required for RNA polymerase III (Pol III)-mediated transcription, is a nucleolar protein and modulates Pol I-mediated transcription. We showed that BRF1 can be localized to the nucleolus in several human cell types. BRF1 expression correlates positively with Pol I product levels and tumour cell growth in vitro and in vivo. Pol III transcription inhibition assays confirmed that BRF1 modulates Pol I-directed transcription in an independent manner rather than through a Pol III product-to-45S pre-rRNA feedback mode. Mechanistically, BRF1 binds to the Pol I transcription machinery components and can be recruited to the rDNA promoter along with them. Additionally, alteration of BRF1 expression affects the recruitment of Pol I transcription machinery components to the rDNA promoter and the expression of TBP and TAF1A. These findings indicate that BRF1 modulates Pol I-directed transcription by controlling the expression of selective factor 1 subunits. In summary, we identified a novel role of BRF1 in Pol I-directed transcription, suggesting that BRF1 can independently regulate both Pol I- and Pol III-mediated transcription and act as a key coordinator of Pol I and Pol III.
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Affiliation(s)
- Juan Wang
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China.,School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Qiyue Chen
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xin Wang
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PL, UK
| | - Shasha Zhao
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Huan Deng
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Baoqiang Guo
- School of Healthcare Science, Manchester Metropolitan University, Manchester M1 5GD, UK
| | - Cheng Zhang
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xiaoye Song
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Wensheng Deng
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Tongcun Zhang
- School of Life Science and Health, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Hongwei Ni
- School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
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2
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Goldkamp AK, Li Y, Rivera RM, Hagen DE. Characterization of tRNA expression profiles in large offspring syndrome. BMC Genomics 2022; 23:273. [PMID: 35392796 PMCID: PMC8988405 DOI: 10.1186/s12864-022-08496-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 03/23/2022] [Indexed: 11/10/2022] Open
Abstract
Background Assisted Reproductive Technologies (ART) use can increase the risk of congenital overgrowth syndromes, such as large offspring syndrome (LOS) in ruminants. Epigenetic variations are known to influence gene expression and differentially methylated regions (DMRs) were previously determined to be associated with LOS in cattle. We observed DMRs overlapping tRNA clusters which could affect tRNA abundance and be associated with tissue specificity or overgrowth. Variations in tRNA expression have been identified in several disease pathways suggesting an important role in the regulation of biological processes. Understanding the role of tRNA expression in cattle offers an opportunity to reveal mechanisms of regulation at the translational level. We analyzed tRNA expression in the skeletal muscle and liver tissues of day 105 artificial insemination-conceived, ART-conceived with a normal body weight, and ART-conceived bovine fetuses with a body weight above the 97th percentile compared to Control-AI. Results Despite the centrality of tRNAs to translation, in silico predictions have revealed dramatic differences in the number of tRNA genes between humans and cattle (597 vs 1,659). Consistent with reports in human, only a fraction of predicted tRNA genes are expressed. We detected the expression of 474 and 487 bovine tRNA genes in the muscle and liver with the remainder being unexpressed. 193 and 198 unique tRNA sequences were expressed in all treatment groups within muscle and liver respectively. In addition, an average of 193 tRNA sequences were expressed within the same treatment group in different tissues. Some tRNA isodecoders were differentially expressed between treatment groups. In the skeletal muscle and liver, we categorized 11 tRNA isoacceptors with undetected expression as well as an isodecoder that was unexpressed in the liver (SerGGA). Our results identified variation in the proportion of tRNA gene copies expressed between tissues and differences in the highest contributing tRNA anticodon within an amino acid family due to treatment and tissue type. Out of all amino acid families, roughly half of the most highly expressed tRNA isoacceptors correlated to their most frequent codon in the bovine genome. Conclusion Although the number of bovine tRNA genes is nearly triple of that of the tRNA genes in human, there is a shared occurrence of transcriptionally inactive tRNA genes in both species. We detected differential expression of tRNA genes as well as tissue- and treatment- specific tRNA transcripts with unique sequence variations that could modulate translation during protein homeostasis or cellular stress, and give rise to regulatory products targeting genes related to overgrowth in the skeletal muscle and/or tumor development in the liver of LOS individuals. While the absence of certain isodecoders may be relieved by wobble base pairing, missing tRNA species could increase the likelihood of mistranslation or mRNA degradation. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08496-7.
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Affiliation(s)
- Anna K Goldkamp
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Yahan Li
- Division of Animal Sciences, University of Missouri, Columbia, MO, USA
| | - Rocio M Rivera
- Division of Animal Sciences, University of Missouri, Columbia, MO, USA
| | - Darren E Hagen
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK, USA.
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3
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Qiu Z, Wang Q, Liu L, Li G, Hao Y, Ning S, Zhang L, Zhang X, Chen Y, Wu J, Wang X, Yang S, Lin Y, Xu S. Riddle of the Sphinx: Emerging Role of Transfer RNAs in Human Cancer. Front Pharmacol 2021; 12:794986. [PMID: 34975491 PMCID: PMC8714751 DOI: 10.3389/fphar.2021.794986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/10/2021] [Indexed: 01/16/2023] Open
Abstract
The dysregulation of transfer RNA (tRNA) expression contributes to the diversity of proteomics, heterogeneity of cell populations, and instability of the genome, which may be related to human cancer susceptibility. However, the relationship between tRNA dysregulation and cancer susceptibility remains elusive because the landscape of cancer-associated tRNAs has not been portrayed yet. Furthermore, the molecular mechanisms of tRNAs involved in tumorigenesis and cancer progression have not been systematically understood. In this review, we detail current knowledge of cancer-related tRNAs and comprehensively summarize the basic characteristics and functions of these tRNAs, with a special focus on their role and involvement in human cancer. This review bridges the gap between tRNAs and cancer and broadens our understanding of their relationship, thus providing new insights and strategies to improve the potential clinical applications of tRNAs for cancer diagnosis and therapy.
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Affiliation(s)
- Zhilin Qiu
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Qin Wang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Lei Liu
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Guozheng Li
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Yi Hao
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Shipeng Ning
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Lei Zhang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Xin Zhang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Yihai Chen
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Jiale Wu
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Xinheng Wang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Shuai Yang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Yaoxin Lin
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, China
- *Correspondence: Yaoxin Lin, ; Shouping Xu,
| | - Shouping Xu
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China
- *Correspondence: Yaoxin Lin, ; Shouping Xu,
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4
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Guan L, Grigoriev A. Computational meta-analysis of ribosomal RNA fragments: potential targets and interaction mechanisms. Nucleic Acids Res 2021; 49:4085-4103. [PMID: 33772581 PMCID: PMC8053083 DOI: 10.1093/nar/gkab190] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/18/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022] Open
Abstract
The most abundant cellular RNA species, ribosomal RNA (rRNA), appears to be a source of massive amounts of non-randomly generated fragments. We found rRNA fragments (rRFs) in immunoprecipitated Argonaute (Ago-IP) complexes in human and mouse cells and in small RNA sequencing datasets. In human Ago1-IP, guanine-rich rRFs were preferentially cut in single-stranded regions of mature rRNAs between pyrimidines and adenosine, and non-randomly paired with cellular transcripts in crosslinked chimeras. Numerous identical rRFs were found in the cytoplasm and nucleus in mouse Ago2-IP. We report specific interaction motifs enriched in rRF-target pairs. Locations of such motifs on rRFs were compatible with the Ago structural features and patterns of the Ago-RNA crosslinking in both species. Strikingly, many of these motifs may bind to double-stranded regions on target RNAs, suggesting a potential pathway for regulating translation by unwinding mRNAs. Occurring on either end of rRFs and matching intronic, untranslated or coding regions in targets, such interaction sites extend the concept of microRNA seed regions. Targeting both borders of certain short introns, rRFs may be involved in their biogenesis or function, facilitated by Ago. Frequently dismissed as noise, rRFs are poised to greatly enrich the known functional spectrum of small RNA regulation.
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Affiliation(s)
- Lingyu Guan
- Department of Biology, Center for Computational and Integrative Biology, Rutgers University, Camden, NJ 08102, USA
| | - Andrey Grigoriev
- Department of Biology, Center for Computational and Integrative Biology, Rutgers University, Camden, NJ 08102, USA
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5
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Sun Z, Tan J, Zhao M, Peng Q, Zhou M, Zuo S, Wu F, Li X, Dong Y, Xie M, Yang Y, Zhou J, Liu X, He Q, He Z, Yu X, He Q. Integrated genomic analysis reveals regulatory pathways and dynamic landscapes of the tRNA transcriptome. Sci Rep 2021; 11:5226. [PMID: 33664286 PMCID: PMC7933247 DOI: 10.1038/s41598-021-83469-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 02/01/2021] [Indexed: 11/25/2022] Open
Abstract
tRNAs and tRNA-derived RNA fragments (tRFs) play various roles in many cellular processes outside of protein synthesis. However, comprehensive investigations of tRNA/tRF regulation are rare. In this study, we used new algorithms to extensively analyze the publicly available data from 1332 ChIP-Seq and 42 small-RNA-Seq experiments in human cell lines and tissues to investigate the transcriptional and posttranscriptional regulatory mechanisms of tRNAs. We found that histone acetylation, cAMP, and pluripotency pathways play important roles in the regulation of the tRNA gene transcription in a cell-specific manner. Analysis of RNA-Seq data identified 950 high-confidence tRFs, and the results suggested that tRNA pools are dramatically distinct across the samples in terms of expression profiles and tRF composition. The mismatch analysis identified new potential modification sites and specific modification patterns in tRNA families. The results also show that RNA library preparation technologies have a considerable impact on tRNA profiling and need to be optimized in the future.
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Affiliation(s)
- Zefang Sun
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Jia Tan
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Minqiong Zhao
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Qiyao Peng
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Mingqing Zhou
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Shanru Zuo
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Feilong Wu
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Xueguang Li
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Yangyang Dong
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Ming Xie
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Yide Yang
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Junhua Zhou
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Xianghua Liu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine One Baylor Plaza, Houston, TX, 77-30, USA
| | - Quanze He
- The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, People's Republic of China
| | - Zuping He
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Xing Yu
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China
| | - Quanyuan He
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Tongzipo Road 371, Changsha, 410013, Hunan, People's Republic of China.
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6
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Dwivedi SKD, Rao G, Dey A, Mukherjee P, Wren JD, Bhattacharya R. Small Non-Coding-RNA in Gynecological Malignancies. Cancers (Basel) 2021; 13:1085. [PMID: 33802524 PMCID: PMC7961667 DOI: 10.3390/cancers13051085] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/18/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Gynecologic malignancies, which include cancers of the cervix, ovary, uterus, vulva, vagina, and fallopian tube, are among the leading causes of female mortality worldwide, with the most prevalent being endometrial, ovarian, and cervical cancer. Gynecologic malignancies are complex, heterogeneous diseases, and despite extensive research efforts, the molecular mechanisms underlying their development and pathology remain largely unclear. Currently, mechanistic and therapeutic research in cancer is largely focused on protein targets that are encoded by about 1% of the human genome. Our current understanding of 99% of the genome, which includes noncoding RNA, is limited. The discovery of tens of thousands of noncoding RNAs (ncRNAs), possessing either structural or regulatory functions, has fundamentally altered our understanding of genetics, physiology, pathophysiology, and disease treatment as they relate to gynecologic malignancies. In recent years, it has become clear that ncRNAs are relatively stable, and can serve as biomarkers for cancer diagnosis and prognosis, as well as guide therapy choices. Here we discuss the role of small non-coding RNAs, i.e., microRNAs (miRs), P-Element induced wimpy testis interacting (PIWI) RNAs (piRNAs), and tRNA-derived small RNAs in gynecological malignancies, specifically focusing on ovarian, endometrial, and cervical cancer.
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Affiliation(s)
- Shailendra Kumar Dhar Dwivedi
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.K.D.D.); (A.D.)
| | - Geeta Rao
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (G.R.); (P.M.)
| | - Anindya Dey
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.K.D.D.); (A.D.)
| | - Priyabrata Mukherjee
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (G.R.); (P.M.)
- Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jonathan D. Wren
- Biochemistry and Molecular Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Resham Bhattacharya
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.K.D.D.); (A.D.)
- Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
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7
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Huang SQ, Sun B, Xiong ZP, Shu Y, Zhou HH, Zhang W, Xiong J, Li Q. The dysregulation of tRNAs and tRNA derivatives in cancer. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2018; 37:101. [PMID: 29743091 PMCID: PMC5944149 DOI: 10.1186/s13046-018-0745-z] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/29/2018] [Indexed: 11/14/2022]
Abstract
Transfer RNAs (tRNAs), traditionally considered to participate in protein translation, were interspersed in the entire genome. Recent studies suggested that dysregulation was observed in not only tRNAs, but also tRNA derivatives generated by the specific cleavage of pre- and mature tRNAs in the progression of cancer. Accumulating evidence had identified that certain tRNAs and tRNA derivatives were involved in proliferation, metastasis and invasiveness of cancer cell, as well as tumor growth and angiogenesis in several malignant human tumors. This paper reviews the importance of the dysregulation of tRNAs and tRNA derivatives during the development of cancer, such as breast cancer, lung cancer, and melanoma, aiming at a better understanding of the tumorigenesis and providing new ideas for the treatment of these cancers.
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Affiliation(s)
- Shi-Qiong Huang
- Department of Clinical Pharmacology, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410078, People's Republic of China
| | - Bao Sun
- Department of Clinical Pharmacology, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410078, People's Republic of China
| | - Zong-Ping Xiong
- Department of Clinical Pharmacology, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410078, People's Republic of China
| | - Yan Shu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, MD, USA
| | - Hong-Hao Zhou
- Department of Clinical Pharmacology, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410078, People's Republic of China
| | - Wei Zhang
- Department of Clinical Pharmacology, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, People's Republic of China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410078, People's Republic of China
| | - Jing Xiong
- Department of gynaecology and obstetrics, The Second Xiangya Hospital of Central South University, Central South University, Changsha, 410078, People's Republic of China.
| | - Qing Li
- Department of Clinical Pharmacology, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, People's Republic of China. .,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410078, People's Republic of China.
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8
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WITHDRAWN: Abnormal expression of TFIIIB subunits and RNA Pol III genes is associated with hepatocellular carcinoma. LIVER RESEARCH 2017. [DOI: 10.1016/j.livres.2017.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Lei J, Chen S, Zhong S. Abnormal expression of TFIIIB subunits and RNA Pol III genes is associated with hepatocellular carcinoma. LIVER RESEARCH 2017; 1:112-120. [PMID: 29276645 PMCID: PMC5739085 DOI: 10.1016/j.livres.2017.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The levels of the products of RNA polymerase III-dependent genes (Pol III genes), including tRNAs and 5S rRNA, are elevated in transformed and tumor cells, which potentiate tumorigenesis. TFIIB-related factor 1 (Brf1) is a key transcription factor and specifically regulates the transcription of Pol III genes. In vivo and in vitro studies have demonstrated that a decrease in Brf1 reduces Pol III gene transcription and is sufficient for inhibiting cell transformation and tumor formation. Emerging evidence indicates that dysregulation of Brf1 and Pol III genes is linked to the development of hepatocellular carcinoma (HCC) in humans and animals. We have reported that Brf1 is overexpressed in human liver cancer patients and that those with high Brf1 levels have shorter survivals. This review summarizes the effects of dysregulation of these genes on HCC and their regulation by signaling pathways and epigenetics. These novel data should help us determine the molecular mechanisms of HCC from a different perspective and guide the development of therapeutic approaches for HCC patients.
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Affiliation(s)
- Junxia Lei
- School of medicine, South china university of technology, China
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Songlin Chen
- Department of Cardiothoracic Surgery, Xiamen University Affiliated Southeast Hospital, China
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Shuping Zhong
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Corresponding author. Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. (S. Zhong)
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10
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Shigematsu M, Honda S, Loher P, Telonis AG, Rigoutsos I, Kirino Y. YAMAT-seq: an efficient method for high-throughput sequencing of mature transfer RNAs. Nucleic Acids Res 2017; 45:e70. [PMID: 28108659 PMCID: PMC5605243 DOI: 10.1093/nar/gkx005] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 01/03/2017] [Indexed: 11/18/2022] Open
Abstract
Besides translation, transfer RNAs (tRNAs) play many non-canonical roles in various biological pathways and exhibit highly variable expression profiles. To unravel the emerging complexities of tRNA biology and molecular mechanisms underlying them, an efficient tRNA sequencing method is required. However, the rigid structure of tRNA has been presenting a challenge to the development of such methods. We report the development of Y-shaped Adapter-ligated MAture TRNA sequencing (YAMAT-seq), an efficient and convenient method for high-throughput sequencing of mature tRNAs. YAMAT-seq circumvents the issue of inefficient adapter ligation, a characteristic of conventional RNA sequencing methods for mature tRNAs, by employing the efficient and specific ligation of Y-shaped adapter to mature tRNAs using T4 RNA Ligase 2. Subsequent cDNA amplification and next-generation sequencing successfully yield numerous mature tRNA sequences. YAMAT-seq has high specificity for mature tRNAs and high sensitivity to detect most isoacceptors from minute amount of total RNA. Moreover, YAMAT-seq shows quantitative capability to estimate expression levels of mature tRNAs, and has high reproducibility and broad applicability for various cell lines. YAMAT-seq thus provides high-throughput technique for identifying tRNA profiles and their regulations in various transcriptomes, which could play important regulatory roles in translation and other biological processes.
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Affiliation(s)
- Megumi Shigematsu
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Shozo Honda
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Phillipe Loher
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Aristeidis G Telonis
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Isidore Rigoutsos
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Yohei Kirino
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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11
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Shigematsu M, Kirino Y. 5'-Terminal nucleotide variations in human cytoplasmic tRNAHisGUG and its 5'-halves. RNA (NEW YORK, N.Y.) 2017; 23:161-168. [PMID: 27879434 PMCID: PMC5238791 DOI: 10.1261/rna.058024.116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/18/2016] [Indexed: 06/06/2023]
Abstract
Transfer RNAs (tRNAs) are fundamental adapter components of translational machinery. tRNAs can further serve as a source of tRNA-derived noncoding RNAs that play important roles in various biological processes beyond translation. Among all species of tRNAs, tRNAHisGUG has been known to uniquely contain an additional guanosine residue at the -1 position (G-1) of its 5'-end. To analyze this -1 nucleotide in detail, we developed a TaqMan qRT-PCR method that can distinctively quantify human mature cytoplasmic tRNAHisGUG containing G-1, U-1, A-1, or C-1 or lacking the -1 nucleotide (starting from G1). Application of this method to the mature tRNA fraction of BT-474 breast cancer cells revealed the presence of tRNAHisGUG containing U-1 as well as the one containing G-1 Moreover, tRNA lacking the -1 nucleotide was also detected, thus indicating the heterogeneous expression of 5'-tRNAHisGUG variants. A sequence library of sex hormone-induced 5'-tRNA halves (5'-SHOT-RNAs), identified via cP-RNA-seq of a BT-474 small RNA fraction, also demonstrated the expression of 5'-tRNAHisGUG halves containing G-1, U-1, or G1 as 5'-terminal nucleotides. Although the detected 5'-nucleotide species were identical, the relative abundances differed widely between mature tRNA and 5'-half from the same BT-474 cells. The majority of mature tRNAs contained the -1 nucleotide, whereas the majority of 5'-halves lacked this nucleotide, which was biochemically confirmed using a primer extension assay. These results reveal the novel identities of tRNAHisGUG molecules and provide insights into tRNAHisGUG maturation and the regulation of tRNA half production.
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Affiliation(s)
- Megumi Shigematsu
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | - Yohei Kirino
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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12
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Grewal SS. Why should cancer biologists care about tRNAs? tRNA synthesis, mRNA translation and the control of growth. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:898-907. [PMID: 25497380 DOI: 10.1016/j.bbagrm.2014.12.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/01/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
Transfer RNAs (tRNAs) are essential for mRNA translation. They are transcribed in the nucleus by RNA polymerase III and undergo many modifications before contributing to cytoplasmic protein synthesis. In this review I highlight our understanding of how tRNA biology may be linked to the regulation of mRNA translation, growth and tumorigenesis. First, I review how oncogenes and tumour suppressor signalling pathways, such as the PI3 kinase/TORC1, Ras/ERK, Myc, p53 and Rb pathways, regulate Pol III and tRNA synthesis. In several cases, this regulation contributes to cell, tissue and body growth, and has implications for our understanding of tumorigenesis. Second, I highlight some recent work, particularly in model organisms such as yeast and Drosophila, that shows how alterations in tRNA synthesis may be not only necessary, but also sufficient to drive changes in mRNA translation and growth. These effects may arise due to both absolute increases in total tRNA levels, but also changes in the relative levels of tRNAs in the overall pool. Finally, I review some recent studies that have revealed how tRNA modifications (amino acid acylation, base modifications, subcellular shuttling, and cleavage) can be regulated by growth and stress cues to selectively influence mRNA translation. Together these studies emphasize the importance of the regulation of tRNA synthesis and modification as critical control points in protein synthesis and growth. This article is part of a Special Issue entitled: Translation and Cancer.
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Affiliation(s)
- Savraj S Grewal
- Department of Biochemistry and Molecular Biology, Clark H. Smith Brain Tumour Centre, Southern Alberta Cancer Research Institute, University of Calgary, HRIC, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
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13
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Abstract
Transfer RNAs (tRNA) are best known for their role as adaptors during translation of the genetic code. Beyond their canonical role during protein biosynthesis, tRNAs also perform additional functions in both prokaryotes and eukaryotes for example in regulating gene expression. Aminoacylated tRNAs have also been implicated as substrates for non-ribosomal peptide bond formation, post-translational protein labeling, modification of phospholipids in the cell membrane, and antibiotic biosyntheses. Most recently tRNA fragments, or tRFs, have also been recognized to play regulatory roles. Here, we examine in more detail some of the new functions emerging for tRNA in a variety of cellular processes outside of protein synthesis.
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Affiliation(s)
- Medha Raina
- Department of Microbiology, The Ohio State Biochemistry Program, The Ohio State University Columbus, OH, USA ; Center for RNA Biology, The Ohio State University Columbus, OH, USA
| | - Michael Ibba
- Department of Microbiology, The Ohio State Biochemistry Program, The Ohio State University Columbus, OH, USA ; Center for RNA Biology, The Ohio State University Columbus, OH, USA
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14
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Bravo IG, Müller M. Codon usage in papillomavirus genes: practical and functional aspects. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/095741905x24996] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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15
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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: 163] [Impact Index Per Article: 14.8] [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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16
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Andrews WJ, Panova T, Normand C, Gadal O, Tikhonova IG, Panov KI. Old drug, new target: ellipticines selectively inhibit RNA polymerase I transcription. J Biol Chem 2013; 288:4567-82. [PMID: 23293027 DOI: 10.1074/jbc.m112.411611] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Transcription by RNA polymerase I (Pol-I) is the main driving force behind ribosome biogenesis, a fundamental cellular process that requires the coordinated transcription of all three nuclear polymerases. Increased Pol-I transcription and the concurrent increase in ribosome biogenesis has been linked to the high rates of proliferation in cancers. The ellipticine family contains a number of potent anticancer therapeutic agents, some having progressed to stage I and II clinical trials; however, the mechanism by which many of the compounds work remains unclear. It has long been thought that inhibition of Top2 is the main reason behind the drugs antiproliferative effects. Here we report that a number of the ellipticines, including 9-hydroxyellipticine, are potent and specific inhibitors of Pol-I transcription, with IC(50) in vitro and in cells in the nanomolar range. Essentially, the drugs did not affect Pol-II and Pol-III transcription, demonstrating a high selectivity. We have shown that Pol-I inhibition occurs by a p53-, ATM/ATR-, and Top2-independent mechanism. We discovered that the drug influences the assembly and stability of preinitiation complexes by targeting the interaction between promoter recognition factor SL1 and the rRNA promoter. Our findings will have an impact on the design and development of novel therapeutic agents specifically targeting ribosome biogenesis.
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Affiliation(s)
- William J Andrews
- School of Biological Sciences, The Queen’s University Belfast, Belfast BT9 7BL, United Kingdom
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17
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Moir RD, Willis IM. Regulation of pol III transcription by nutrient and stress signaling pathways. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:361-75. [PMID: 23165150 DOI: 10.1016/j.bbagrm.2012.11.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 11/06/2012] [Accepted: 11/08/2012] [Indexed: 12/29/2022]
Abstract
Transcription by RNA polymerase III (pol III) is responsible for ~15% of total cellular transcription through the generation of small structured RNAs such as tRNA and 5S RNA. The coordinate synthesis of these molecules with ribosomal protein mRNAs and rRNA couples the production of ribosomes and their tRNA substrates and balances protein synthetic capacity with the growth requirements of the cell. Ribosome biogenesis in general and pol III transcription in particular is known to be regulated by nutrient availability, cell stress and cell cycle stage and is perturbed in pathological states. High throughput proteomic studies have catalogued modifications to pol III subunits, assembly, initiation and accessory factors but most of these modifications have yet to be linked to functional consequences. Here we review our current understanding of the major points of regulation in the pol III transcription apparatus, the targets of regulation and the signaling pathways known to regulate their function. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- Robyn D Moir
- Departments of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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18
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19
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Applications of different weighting schemes to improve pathway-based analysis. Comp Funct Genomics 2011; 2011:463645. [PMID: 21687588 PMCID: PMC3114410 DOI: 10.1155/2011/463645] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 02/26/2011] [Indexed: 11/28/2022] Open
Abstract
Conventionally, pathway-based analysis assumes that genes in a pathway equally contribute to a biological function, thus assigning uniform weight to genes. However, this assumption has been proved incorrect, and applying uniform weight in the pathway analysis may not be an appropriate approach for the tasks like molecular classification of diseases, as genes in a functional group may have different predicting power. Hence, we propose to use different weights to genes in pathway-based analysis and devise four weighting schemes. We applied them in two existing pathway analysis methods using both real and simulated gene expression data for pathways. Among all schemes, random weighting scheme, which generates random weights and selects optimal weights minimizing an objective function, performs best in terms of P value or error rate reduction. Weighting changes pathway scoring and brings up some new significant pathways, leading to the detection of disease-related genes that are missed under uniform weight.
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20
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Pol II and its associated epigenetic marks are present at Pol III-transcribed noncoding RNA genes. Nat Struct Mol Biol 2010; 17:629-34. [PMID: 20418881 PMCID: PMC2917008 DOI: 10.1038/nsmb.1806] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 03/15/2010] [Indexed: 12/16/2022]
Abstract
Epigenetic control is an important aspect of gene regulation. Despite detailed understanding of protein-coding gene expression, the transcription of non-coding RNA genes by RNA polymerase (pol) III is less well characterized. Here we profile the epigenetic features of pol III target genes throughout the human genome. This reveals that the chromatin landscape of pol III-transcribed genes resembles that of pol II templates in many ways, although there are also clear differences. Our analysis also discovered an entirely unexpected phenomenon, namely that pol II is present at the majority of genomic loci that are bound by pol III.
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Athineos D, Marshall L, White RJ. Regulation of TFIIIB during F9 cell differentiation. BMC Mol Biol 2010; 11:21. [PMID: 20226026 PMCID: PMC2842266 DOI: 10.1186/1471-2199-11-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 03/12/2010] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Differentiation of F9 embryonal carcinoma (EC) cells into parietal endoderm (PE) provides a tractable model system for studying molecular events during early and inaccessible stages of murine development. PE formation is accompanied by extensive changes in gene expression both in vivo and in culture. One of the most dramatic is the ~10-fold decrease in transcriptional output by RNA polymerase (pol) III. This has been attributed to changes in activity of TFIIIB, a factor that is necessary and sufficient to recruit pol III to promoters. The goal of this study was to identify molecular changes that can account for the low activity of TFIIIB following F9 cell differentiation. RESULTS Three essential subunits of TFIIIB decrease in abundance as F9 cells differentiate; these are Brf1 and Bdp1, which are pol III-specific, and TBP, which is also used by pols I and II. The decreased levels of Brf1 and Bdp1 proteins can be explained by reduced expression of the corresponding mRNAs. However, this is not the case for TBP, which is regulated post-transcriptionally. In proliferating cells, pol III transcription is stimulated by the proto-oncogene product c-Myc and the mitogen-activated protein kinase Erk, both of which bind to TFIIIB. However, c-Myc levels fall during differentiation and Erk becomes inactive through dephosphorylation. The diminished abundance of TFIIIB is therefore likely to be compounded by changes to these positive regulators that are required for its full activity. In addition, PE cells have elevated levels of the retinoblastoma protein RB, which is known to bind and repress TFIIIB. CONCLUSION The low activity of TFIIIB in PE can be attributed to a combination of changes, any one of which could be sufficient to inhibit pol III transcription. Declining levels of essential TFIIIB subunits and of activators that are required for maximal TFIIIB activity are accompanied by an increase in a potent repressor of TFIIIB. These events provide fail-safe guarantees to ensure that pol III output is appropriate to the diminished metabolic requirements of terminally differentiated cells.
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Affiliation(s)
- Dimitris Athineos
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
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22
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Kantidakis T, White RJ. Dr1 (NC2) is present at tRNA genes and represses their transcription in human cells. Nucleic Acids Res 2009; 38:1228-39. [PMID: 19965767 PMCID: PMC2831321 DOI: 10.1093/nar/gkp1102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Dr1 (also known as NC2β) was identified as a repressor of RNA polymerase (pol) II transcription. It was subsequently shown to inhibit pol III transcription when expressed at high levels in vitro or in yeast cells. However, endogenous Dr1 was not detected at pol III-transcribed genes in growing yeast. In contrast, we demonstrate that endogenous Dr1 is present at pol III templates in human cells, as is its dimerization partner DRAP1 (also called NC2α). Expression of tRNA by pol III is selectively enhanced by RNAi-mediated depletion of endogenous human Dr1, but we found no evidence that DRAP1 influences pol III output in vivo. A stable association was detected between endogenous Dr1 and the pol III-specific transcription factor Brf1. This interaction may recruit Dr1 to pol III templates in vivo, as crosslinking to these sites increases following Brf1 induction. On the basis of these data, we conclude that the physiological functions of human Dr1 include regulation of pol III transcription.
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Affiliation(s)
- Theodoros Kantidakis
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
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The JNKs differentially regulate RNA polymerase III transcription by coordinately modulating the expression of all TFIIIB subunits. Proc Natl Acad Sci U S A 2009; 106:12682-7. [PMID: 19620725 DOI: 10.1073/pnas.0904843106] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
RNA polymerase (pol) III-dependent transcription is subject to stringent regulation by tumor suppressors and oncogenic proteins and enhanced RNA pol III transcription is essential for cellular transformation and tumorigenesis. Since the c-Jun N-terminal kinases (JNKs) display both oncogenic and tumor suppressor properties, the roles of these proteins in regulating RNA pol III transcription were examined. In both mouse and human cells, loss or reduction in JNK1 expression represses RNA pol III transcription. In contrast, loss or reduction in JNK2 expression induces transcription. The JNKs coordinately regulate expression of all 3 TFIIIB subunits. While JNK1 positively regulates TBP expression, the RNA pol III-specific factors, Brf1 and Bdp1, JNK2 negatively regulates their expression. Brf1 is coregulated with TBP through the JNK target, Elk-1. Reducing Elk-1 expression decreases Brf1 expression. Decreasing JNK1 expression reduces Elk-1 occupancy at the Brf1 promoter, while decreasing JNK2 expression enhances recruitment of Elk-1 to the Brf1 promoter. In contrast, regulation of Bdp1 occurs through JNK-mediated alterations in TBP expression. Altered TBP expression mimics the effect of reduced JNK1 or JNK2 levels on Bdp1 expression. Decreasing JNK1 expression reduces the occupancy of TBP at the Bdp1 promoter, while decreasing JNK2 expression enhances recruitment of TBP to the Bdp1 promoter. Together, these results provide a molecular mechanism for regulating RNA pol III transcription through the coordinate control of TFIIIB subunit expression and elucidate opposing functions for the JNKs in regulating a large class of genes that dictate the biosynthetic capacity of cells.
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Abstract
RNA polymerase III (Pol III) makes a variety of small non-coding RNAs, such as tRNA and 5S ribosomal RNA. Increased expression of pol III products is often observed in transformed cells. Much progress has been made in determining how Pol III-dependent transcription is regulated and how it increases in cancers, but the importance of this increase has not been clearly established. New evidence suggests that Pol III output can substantially affect transformation.
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Affiliation(s)
- Lynne Marshall
- Beatson Institute for Cancer Research, Bearsden, Glasgow, UK
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25
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RNA polymerases I and III, non-coding RNAs and cancer. Trends Genet 2008; 24:622-9. [PMID: 18980784 DOI: 10.1016/j.tig.2008.10.003] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 10/06/2008] [Accepted: 10/06/2008] [Indexed: 12/12/2022]
Abstract
Oncogenically transformed cells overexpress the non-coding RNAs, such as pre-ribosomal RNA (rRNA) and transfer RNA (tRNA), which are produced by RNA polymerases (Pols) I and III. Recent results indicate that levels of pre-rRNA have prognostic value and that a tRNA has oncogenic potential. Transcription by Pols I and III is restrained in healthy cells by the tumour suppressors RB, p53, ARF and PTEN. Such restraints are compromised during cell transformation and the problem is accentuated by oncogene products, such as c-Myc, that stimulate the output of Pol I and Pol III. The resultant increases in rRNA and tRNA expression might promote the generation of cancers.
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Cabarcas S, Jacob J, Veras I, Schramm L. Differential expression of the TFIIIB subunits Brf1 and Brf2 in cancer cells. BMC Mol Biol 2008; 9:74. [PMID: 18700021 PMCID: PMC2533013 DOI: 10.1186/1471-2199-9-74] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 08/12/2008] [Indexed: 12/27/2022] Open
Abstract
Background RNA polymerase (pol) III transcription is specifically elevated in a variety of cancers and is a target of regulation by a variety of tumor suppressors and oncogenes. Accurate initiation by RNA pol III is dependent on TFIIIB. In higher eukaryotes, two forms of TFIIIB have been characterized. TFIIIB required for proper initiation from gene internal RNA pol III promoters is comprised of TBP, Bdp1, and Brf1. Proper initiation from gene external RNA pol III promoters requires TBP, Bdp1, and Brf2. We hypothesized that deregulation of RNA polymerase III transcription in cancer may be a consequence of altered TFIIIB expression Results Here, we report: (1) the TFIIIB subunits Brf1 and Brf2 are differentially expressed in a variety of cancer cell lines: (2) the Brf1 and Brf2 promoters differ in activity in cancer cell lines, and (3) VAI transcription is universally elevated, as compared to U6, in breast, prostate and cervical cancer cells. Conclusion Deregulation of TFIIIB-mediated transcription may be an important step in tumor development. We demonstrate that Brf1 and Brf2 mRNA are differentially expressed in a variety of cancer cells and that the Brf2 promoter is more active than the Brf1 promoter in all cell lines tested. We also demonstrate, that Brf1-dependent VAI transcription was significantly higher than the Brf2-dependent U6 snRNA transcription in all cancer cell lines tested. The data presented suggest that Brf2 protein expression levels correlate with U6 promoter activity in the breast, cervical and prostate cell lines tested. Interestingly, the Brf1 protein levels did not vary considerably in HeLa, MCF-7 and DU-145 cells, yet Brf1 mRNA expression varied considerably in breast, prostate and cervical cancer cell lines tested. Thus, Brf1 promoter activity and Brf1 protein expression levels did not correlate well with Brf1-dependent transcription levels. Taken together, we reason that deregulation of Brf1 and Brf2 expression could be a key mechanism responsible for the observed deregulation of RNA pol III transcription in cancer cells.
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Affiliation(s)
- Stephanie Cabarcas
- Department of Biological Sciences, St, John's University, 8000 Utopia Parkway, Queens, NY 11439, USA.
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27
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Abstract
RNA polymerase (pol) III contains a dissociable subcomplex that is required for initiation, but not for elongation or termination of transcription. This subcomplex is composed of subunits RPC3, RPC6 and RPC7, and interacts with TFIIIB, a factor that is necessary and sufficient to support accurate pol III transcription in vitro. Direct binding of TFIIIB to RPC6 is believed to recruit pol III to its genetic templates. However, this has never been tested in vivo. Here we combine chromatin immunoprecipitation with RNA interference to demonstrate that the RPC3/6/7 subcomplex is required for pol III recruitment in mammalian cells. Specific knockdown of RPC6 by RNAi results in post-transcriptional depletion of the other components of the subcomplex, RPC3 and RPC7, without destabilizing core pol III subunits or TFIIIB. The resultant core enzyme is defective in associating with TFIIIB and target genes in vivo. Promoter occupancy by pol II is unaffected, despite sharing five subunits with the pol III core. These observations provide evidence for the validity in vivo of the model for pol III recruitment that was built on biochemical data.
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Affiliation(s)
- Niall S Kenneth
- Institute of Biomedical and Life Sciences, Division of Biochemistry and Molecular Biology, University of Glasgow, Glasgow, G12 8QQ, UK
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28
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Malmberg SE, Adams CM. Insulin signaling and the general amino acid control response. Two distinct pathways to amino acid synthesis and uptake. J Biol Chem 2008; 283:19229-34. [PMID: 18480057 DOI: 10.1074/jbc.m801331200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
ATF4 is a transcription factor that induces a genetic program for amino acid synthesis and amino acid uptake. Previous work demonstrated that ATF4 expression is increased either by insulin or by the general amino acid control (GAAC) response, an evolutionarily ancient pathway that is activated when eukaryotic cells are deprived of amino acids. It is not known whether insulin and the GAAC pathway increase ATF4 expression by the same or different mechanisms. In these studies, we demonstrate that insulin-mediated ATF4 expression occurs as part of a coordinated anabolic program that does not require an essential component of the GAAC pathway, the protein kinase GCN2. Moreover, insulin and the GAAC pathway have an additive effect on expression of ATF4 and downstream mRNAs for amino acid synthesis and uptake. These data suggest that the GAAC pathway may facilitate insulin-mediated anabolism when exogenous amino acids are limiting. We conclude that insulin signaling and the GAAC response comprise two distinct yet complimentary pathways to ATF4 expression, allowing anabolism to be finely tuned to amino acid availability.
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Affiliation(s)
- Sharon E Malmberg
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
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Marshall L, Kenneth NS, White RJ. Elevated tRNA(iMet) synthesis can drive cell proliferation and oncogenic transformation. Cell 2008; 133:78-89. [PMID: 18394991 DOI: 10.1016/j.cell.2008.02.035] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 12/14/2007] [Accepted: 02/06/2008] [Indexed: 12/23/2022]
Abstract
Characteristics of transformed and tumor cells include increased levels of protein synthesis and elevated expression of RNA polymerase (pol) III products, such as tRNAs and 5S rRNA. However, whether deregulated pol III transcription contributes to transformation has been unclear. Generating cell lines expressing an inducible pol III-specific transcription factor, Brf1, allowed us to raise tRNA and 5S rRNA levels specifically. Brf1 induction caused an increase in cell proliferation and oncogenic transformation, whereas depletion of Brf1 impeded transformation. Among the gene products induced by Brf1 is the tRNA(iMet) that initiates polypeptide synthesis. Overexpression of tRNA(iMet) is sufficient to stimulate cell proliferation and allow immortalized fibroblasts to form foci in culture and tumors in mice. The data indicate that elevated tRNA synthesis can promote cellular transformation.
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Affiliation(s)
- Lynne Marshall
- Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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30
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Goodfellow SJ, Graham EL, Kantidakis T, Marshall L, Coppins BA, Oficjalska-Pham D, Gérard M, Lefebvre O, White RJ. Regulation of RNA polymerase III transcription by Maf1 in mammalian cells. J Mol Biol 2008; 378:481-91. [PMID: 18377933 DOI: 10.1016/j.jmb.2008.02.060] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 02/22/2008] [Accepted: 02/25/2008] [Indexed: 11/28/2022]
Abstract
RNA polymerase (pol) III produces essential components of the biosynthetic machinery; therefore, its output is tightly coupled with the rate of cell growth and proliferation. In Saccharomyces cerevisiae, Maf1 is an essential mediator of pol III repression in response to starvation. We demonstrate that a Maf1 ortholog is also used to restrain pol III activity in mouse and human cells. Mammalian Maf1 represses pol III transcription in vitro and in transfected fibroblasts. Furthermore, genetic deletion of Maf1 elevates pol III transcript expression, thus confirming the role of endogenous Maf1 as an inhibitor of mammalian pol III output. Maf1 is detected at chromosomal pol III templates in rodent and human cells. It interacts with pol III as well as its associated initiation factor TFIIIB and is phosphorylated in a serum-sensitive manner in vivo. These aspects of Maf1 function have been conserved between yeast and mammals and are therefore likely to be of fundamental importance in controlling pol III transcriptional activity.
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Affiliation(s)
- Sarah J Goodfellow
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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31
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Kenneth NS, Ramsbottom BA, Gomez-Roman N, Marshall L, Cole PA, White RJ. TRRAP and GCN5 are used by c-Myc to activate RNA polymerase III transcription. Proc Natl Acad Sci U S A 2007; 104:14917-22. [PMID: 17848523 PMCID: PMC1986588 DOI: 10.1073/pnas.0702909104] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Activation of RNA polymerase (pol) II transcription by c-Myc generally involves recruitment of histone acetyltransferases and acetylation of histones H3 and H4. Here, we describe the mechanism used by c-Myc to activate pol III transcription of tRNA and 5S rRNA genes. Within 2 h of its induction, c-Myc appears at these genes along with the histone acetyltransferase GCN5 and the cofactor TRRAP. At the same time, occupancy of the pol III-specific factor TFIIIB increases and histone H3 becomes hyperacetylated, but increased histone H4 acetylation is not detected at these genes. The rapid acetylation of histone H3 and promoter assembly of TFIIIB, c-Myc, GCN5, and TRRAP are followed by recruitment of pol III and transcriptional induction. The selective acetylation of histone H3 distinguishes pol III activation by c-Myc from mechanisms observed in other systems.
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Affiliation(s)
- Niall S. Kenneth
- *Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Ben A. Ramsbottom
- *Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Natividad Gomez-Roman
- *Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Lynne Marshall
- *Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, United Kingdom; and
| | - Philip A. Cole
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Robert J. White
- *Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, United Kingdom; and
- To whom correspondence should be addressed. E-mail:
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32
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Felton-Edkins ZA, Kondrashov A, Karali D, Fairley JA, Dawson CW, Arrand JR, Young LS, White RJ. Epstein-Barr Virus Induces Cellular Transcription Factors to Allow Active Expression of EBER Genes by RNA Polymerase III. J Biol Chem 2006; 281:33871-80. [PMID: 16956891 DOI: 10.1074/jbc.m600468200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The EBER genes of Epstein-Barr virus (EBV) are transcribed by RNA polymerase (pol) III to produce untranslated RNAs that are implicated in oncogenesis. These EBER transcripts are the most highly expressed viral gene products in EBV-transformed cells. We have identified changes to the cellular transcription machinery that may contribute to the high levels of EBER RNA. These include phosphorylation of ATF2, which interacts with EBER promoters. A second is induction of TFIIIC, a pol III-specific factor that activates EBER genes; all five subunits of TFIIIC are overexpressed in EBV-positive cells. In addition, EBV induces BDP1, a subunit of the pol III-specific factor TFIIIB. Although BDP1 is the only TFIIIB subunit induced by EBV, its induction is sufficient to stimulate EBER expression in vivo, implying a limiting function. The elevated levels of BDP1 and TFIIIC in EBV-positive cells stimulate production of tRNA, 7SL, and 5S rRNA. Abnormally high expression of these cellular pol III products may contribute to the ability of EBV to enhance growth potential.
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MESH Headings
- Blotting, Western
- Chromatin Immunoprecipitation
- DNA-Binding Proteins
- Electrophoretic Mobility Shift Assay
- Gene Expression Regulation, Viral/physiology
- Herpesvirus 4, Human/physiology
- Humans
- Mutagenesis, Site-Directed
- Nuclear Matrix-Associated Proteins
- Octamer Transcription Factors
- Promoter Regions, Genetic/genetics
- RNA Polymerase III/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Viral/genetics
- RNA-Binding Proteins
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Factor TFIIIB/genetics
- Transcription Factor TFIIIB/metabolism
- Transcription Factors, TFIII/metabolism
- Transcription, Genetic
- Transfection
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Affiliation(s)
- Zoë A Felton-Edkins
- Institute of Biomedical and Life Sciences, Division of Biochemistry and Molecular Biology, Davidson Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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33
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Goodfellow SJ, Innes F, Derblay LE, MacLellan WR, Scott PH, White RJ. Regulation of RNA polymerase III transcription during hypertrophic growth. EMBO J 2006; 25:1522-33. [PMID: 16541106 PMCID: PMC1440310 DOI: 10.1038/sj.emboj.7601040] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 02/20/2006] [Indexed: 01/19/2023] Open
Abstract
The cell division-independent growth of terminally differentiated cardiomyocytes is commonly associated with cardiovascular disease. We demonstrate that it is accompanied by a substantial rise in transcription by RNA polymerase (pol) III, which produces essential components of the biosynthetic apparatus, including 5S rRNA and tRNAs. This increase in transcription is achieved by changes in both the activity and level of the essential pol III-specific transcription factor TFIIIB. Erk and c-Myc, which directly activate TFIIIB in proliferating fibroblasts, also induce pol III transcription in growing cardiomyocytes. Furthermore, hypertrophic stimulation increases expression of the essential TFIIIB subunit Brf1, an effect not seen when fibroblasts proliferate. Erk mediates this induction of Brf1 expression and therefore contributes in at least two ways to pol III transcriptional activation during hypertrophy. Increased production of tRNA and 5S rRNA will contribute to the enhanced translational capacity required to sustain hypertrophic growth.
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Affiliation(s)
- Sarah J Goodfellow
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
| | - Fiona Innes
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
| | - Louise E Derblay
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
| | - W Robb MacLellan
- Cardiovascular Research Laboratory, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Pamela H Scott
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
| | - Robert J White
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
- Beatson Institute for Cancer Research, Bearsden, Glasgow, UK
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