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Mahat DB, Tippens ND, Martin-Rufino JD, Waterton SK, Fu J, Blatt SE, Sharp PA. Single-cell nascent RNA sequencing unveils coordinated global transcription. Nature 2024:10.1038/s41586-024-07517-7. [PMID: 38839954 DOI: 10.1038/s41586-024-07517-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 05/03/2024] [Indexed: 06/07/2024]
Abstract
Transcription is the primary regulatory step in gene expression. Divergent transcription initiation from promoters and enhancers produces stable RNAs from genes and unstable RNAs from enhancers1,2. Nascent RNA capture and sequencing assays simultaneously measure gene and enhancer activity in cell populations3. However, fundamental questions about the temporal regulation of transcription and enhancer-gene coordination remain unanswered, primarily because of the absence of a single-cell perspective on active transcription. In this study, we present scGRO-seq-a new single-cell nascent RNA sequencing assay that uses click chemistry-and unveil coordinated transcription throughout the genome. We demonstrate the episodic nature of transcription and the co-transcription of functionally related genes. scGRO-seq can estimate burst size and frequency by directly quantifying transcribing RNA polymerases in individual cells and can leverage replication-dependent non-polyadenylated histone gene transcription to elucidate cell cycle dynamics. The single-nucleotide spatial and temporal resolution of scGRO-seq enables the identification of networks of enhancers and genes. Our results suggest that the bursting of transcription at super-enhancers precedes bursting from associated genes. By imparting insights into the dynamic nature of global transcription and the origin and propagation of transcription signals, we demonstrate the ability of scGRO-seq to investigate the mechanisms of transcription regulation and the role of enhancers in gene expression.
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Affiliation(s)
- Dig B Mahat
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nathaniel D Tippens
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Sean K Waterton
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Jiayu Fu
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL, USA
| | - Sarah E Blatt
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Exact Sciences, Madison, WI, USA
| | - Phillip A Sharp
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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2
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Li H, Zhang Y, Bing J, Han J, Hu J, Zhao H, Sun X. Intron-capture RNA-seq reveals the landscape of intronic RNAs in Arabidopsis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 196:75-88. [PMID: 36701993 DOI: 10.1016/j.plaphy.2023.01.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/19/2023] [Indexed: 06/17/2023]
Abstract
Intronic RNAs have been overlooked for a long time: They are functional, but treated as "junk." In this work, we designed a new sequencing strategy to investigate intronic RNAs. By using intron-capture RNA-seq, we systematically analyzed the intronic RNAs in Arabidopsis by zooming into the intronic regions an order of magnitude deeper than in previous work. Our key findings include: (1) Intron-capture RNA-seq is a much more efficient approach to analyze intronic RNAs than total RNA-seq and mRNA-seq. (2) We identified three types of intronic RNAs, and found that the GC pattern differs significantly between the introns with and without intronic RNAs. (3) We detected many hidden elements in introns, including circular RNAs, splice junctions, and transcripts that have previously been overlooked. (4) The expression of these intronic RNAs varies during the time course of pathogen infection, which indicates that an unknown mechanism may exist for these RNAs. (5) We also demonstrated that most of intronic RNAs are detectable in both Arabidopsis and rice, suggesting that these non-coding molecules are conserved. Taken together, this work proposes an efficient strategy to analyze intronic RNAs, and provides an unprecedented view of this essential component in biological pathways.
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Affiliation(s)
- Han Li
- Agricultural Big-Data Research Center, College of Information Science and Engineering, Shandong Agricultural University, Taian, China
| | - Yimai Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jianhao Bing
- Agricultural Big-Data Research Center, College of Information Science and Engineering, Shandong Agricultural University, Taian, China
| | - Jinyu Han
- Agricultural Big-Data Research Center, College of Information Science and Engineering, Shandong Agricultural University, Taian, China
| | - Jiming Hu
- Agricultural Big-Data Research Center, College of Information Science and Engineering, Shandong Agricultural University, Taian, China
| | - Hongwei Zhao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
| | - Xiaoyong Sun
- Agricultural Big-Data Research Center, College of Information Science and Engineering, Shandong Agricultural University, Taian, China.
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3
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Choi Y, Lee HH, Park J, Kim S, Choi S, Moon H, Shin J, Kim JE, Choi GJ, Seo YS, Son H. Intron turnover is essential to the development and pathogenicity of the plant pathogenic fungus Fusarium graminearum. Commun Biol 2022; 5:1129. [PMID: 36289323 PMCID: PMC9606315 DOI: 10.1038/s42003-022-04111-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022] Open
Abstract
Intron lariats excised during the splicing process are rapidly degraded by RNA lariat debranching enzyme (Dbr1) and several exonucleases. Rapid turnover of lariat RNA is essential to cellular RNA homeostasis. However, the functions of Dbr1 have not been investigated in filamentous fungi. Here, we characterized the molecular functions of Dbr1 in Fusarium graminearum, a major fungal plant pathogen. Deletion of FgDBR1 resulted in pleiotropic defects in hyphal growth, conidiation, sexual reproduction, and virulence. Through transcriptome analysis, we revealed that the deletion mutant exhibited global accumulation of intron lariats and upregulation of ribosome-related genes. Excessive accumulation of lariat RNA led to reduced overall protein synthesis, causing various phenotypic defects in the absence of FgDBR1. The results of this study demonstrate that a compromised intron turnover process affects development and pathogenesis in this fungus and that Dbr1 function is critical to plant pathogenic fungi. RNA lariat debranching enzyme Dbr1 is required for intron turnover in the fungal plant pathogen <i>Fusarium graminearum <i > , and accumulation of lariat RNA affects its development and pathogenesis.
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Affiliation(s)
- Yejin Choi
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Hyun-Hee Lee
- grid.262229.f0000 0001 0719 8572Department of Integrated Biological Science, Pusan National University, Busan, 46247 Republic of Korea
| | - Jiyeun Park
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Sieun Kim
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Soyoung Choi
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Heeji Moon
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jiyoung Shin
- grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jung-Eun Kim
- grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Gyung Ja Choi
- grid.29869.3c0000 0001 2296 8192Therapeutic & Biotechnology Division, Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, 34114 Republic of Korea
| | - Young-Su Seo
- grid.262229.f0000 0001 0719 8572Department of Integrated Biological Science, Pusan National University, Busan, 46247 Republic of Korea
| | - Hokyoung Son
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea ,grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
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4
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Shifman BM, Platonova NM, Vasilyev EV, Abdulkhabirova FM, Kachko VA. Circular RNAs and thyroid cancer: closed molecules, open possibilities. Crit Rev Oncol Hematol 2022; 173:103662. [PMID: 35341987 DOI: 10.1016/j.critrevonc.2022.103662] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/22/2022] [Accepted: 03/22/2022] [Indexed: 12/17/2022] Open
Abstract
Thyroid neoplasms requiring differential diagnosis between thyroid cancer and benign tumors can be detected in more than half of the healthy population. A generally accepted method that allows assessing the risk of malignant potential and determining the indications for surgical treatment of thyroid tumor is a fine-needle aspiration biopsy followed by a cytological examination. Nevertheless, in patients with indeterminate categories of cytological conclusions according to Bethesda system, the positive predictive value of the cytology result is significantly lower than desired and often leads to unjustified surgical treatment. In this regard, the search for alternative diagnostic solutions continues. Circular RNAs are a group of non-coding RNAs distinguished by a closed structure formed by covalent bonding of the nucleotide chain ends. Recent studies allow us to conclude that many different circular RNAs are involved in processes mediating oncogenesis in the thyroid gland, and their altered expression in tissue, blood, and exosomes of plasma may be a characteristic sign of thyroid cancer and certain clinicopathological features of its course. The purpose of this review is to analyze the accumulated data on the association of various circular RNAs with thyroid cancer and to discuss possible ways to improve the diagnosis and treatment of the disease based on the assessment of the expression of these molecules.
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Johnson ST, Chu Y, Liu J, Corey DR. Impact of scaffolding protein TNRC6 paralogs on gene expression and splicing. RNA (NEW YORK, N.Y.) 2021; 27:1004-1016. [PMID: 34108231 PMCID: PMC8370741 DOI: 10.1261/rna.078709.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/04/2021] [Indexed: 05/11/2023]
Abstract
TNRC6 is a scaffolding protein that bridges interactions between small RNAs, argonaute (AGO) protein, and effector proteins to control gene expression. There are three paralogs in mammalian cells, TNRC6A, TNRC6B, and TNRC6C These paralogs have ∼40% amino acid sequence identity and the extent of their unique or redundant functions is unclear. Here, we use knockout cell lines, enhanced crosslinking immunoprecipitation (eCLIP), and high-throughput RNA sequencing (RNA-seq) to explore the roles of TNRC6 paralogs in RNA-mediated control of gene expression. We find that the paralogs are largely functionally redundant and changes in levels of gene expression are well-correlated with those observed in AGO knockout cell lines. Splicing changes observed in AGO knockout cell lines are also observed in TNRC6 knockout cells. These data further define the roles of the TNRC6 isoforms as part of the RNA interference (RNAi) machinery.
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Affiliation(s)
- Samantha T Johnson
- UT Southwestern Medical Center, Departments of Pharmacology and Biochemistry, Dallas, Texas 75205, USA
| | - Yongjun Chu
- UT Southwestern Medical Center, Departments of Pharmacology and Biochemistry, Dallas, Texas 75205, USA
| | - Jing Liu
- UT Southwestern Medical Center, Departments of Pharmacology and Biochemistry, Dallas, Texas 75205, USA
| | - David R Corey
- UT Southwestern Medical Center, Departments of Pharmacology and Biochemistry, Dallas, Texas 75205, USA
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6
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Ng AYE, Pek JW. Circular sisRNA identification and characterisation. Methods 2021; 196:138-146. [PMID: 33838268 DOI: 10.1016/j.ymeth.2021.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/30/2021] [Accepted: 04/02/2021] [Indexed: 01/22/2023] Open
Abstract
Stable Intronic Sequence RNA (sisRNA) is a relatively new class of non-coding RNA. Found in many organisms, these sisRNA produced from their host genes are generally involved in regulatory roles, controlling gene expression at multiple levels through active involvement in regulatory feedback loops. Large scale identification of sisRNA via genome-wide RNA sequencing has been difficult, largely in part due to its low abundance. Done on its own, RNA sequencing often yields a large mass of information that is ironically uninformative; the potential sisRNA reads being masked by other highly abundant RNA species like ribosomal RNA and messenger RNA. In this review, we present a practical workflow for the enrichment of circular sisRNA through the use of transcriptionally quiescent systems, rRNA-depletion, and RNase R treatment prior to deep sequencing. This workflow allows circular sisRNA to be reliably detected. We also present various methods to experimentally validate the circularity and stability of the circular sisRNA identified, as well as a few methods for further functional characterisation.
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Affiliation(s)
- Amanda Yunn Ee Ng
- Temasek Life Sciences Laboratory, 1 Research Link National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive, Singapore 117543, Singapore
| | - Jun Wei Pek
- Temasek Life Sciences Laboratory, 1 Research Link National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive, Singapore 117543, Singapore.
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7
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Královičová J, Borovská I, Pengelly R, Lee E, Abaffy P, Šindelka R, Grutzner F, Vořechovský I. Restriction of an intron size en route to endothermy. Nucleic Acids Res 2021; 49:2460-2487. [PMID: 33550394 PMCID: PMC7969005 DOI: 10.1093/nar/gkab046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 11/15/2022] Open
Abstract
Ca2+-insensitive and -sensitive E1 subunits of the 2-oxoglutarate dehydrogenase complex (OGDHC) regulate tissue-specific NADH and ATP supply by mutually exclusive OGDH exons 4a and 4b. Here we show that their splicing is enforced by distant lariat branch points (dBPs) located near the 5' splice site of the intervening intron. dBPs restrict the intron length and prevent transposon insertions, which can introduce or eliminate dBP competitors. The size restriction was imposed by a single dominant dBP in anamniotes that expanded into a conserved constellation of four dBP adenines in amniotes. The amniote clusters exhibit taxon-specific usage of individual dBPs, reflecting accessibility of their extended motifs within a stable RNA hairpin rather than U2 snRNA:dBP base-pairing. The dBP expansion took place in early terrestrial species and was followed by a uridine enrichment of large downstream polypyrimidine tracts in mammals. The dBP-protected megatracts permit reciprocal regulation of exon 4a and 4b by uridine-binding proteins, including TIA-1/TIAR and PUF60, which promote U1 and U2 snRNP recruitment to the 5' splice site and BP, respectively, but do not significantly alter the relative dBP usage. We further show that codons for residues critically contributing to protein binding sites for Ca2+ and other divalent metals confer the exon inclusion order that mirrors the Irving-Williams affinity series, linking the evolution of auxiliary splicing motifs in exons to metallome constraints. Finally, we hypothesize that the dBP-driven selection for Ca2+-dependent ATP provision by E1 facilitated evolution of endothermy by optimizing the aerobic scope in target tissues.
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Affiliation(s)
- Jana Královičová
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Ivana Borovská
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Reuben Pengelly
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
| | - Eunice Lee
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Pavel Abaffy
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Radek Šindelka
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Frank Grutzner
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Igor Vořechovský
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
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8
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Robinson-Thiewes S, McCloskey J, Kimble J. Two classes of active transcription sites and their roles in developmental regulation. Proc Natl Acad Sci U S A 2020; 117:26812-26821. [PMID: 33033228 PMCID: PMC7604424 DOI: 10.1073/pnas.2013163117] [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] [Indexed: 11/18/2022] Open
Abstract
The expression of genes encoding powerful developmental regulators is exquisitely controlled, often at multiple levels. Here, we investigate developmental expression of three conserved genes, Caenorhabditis elegans mpk-1, lag-1, and lag-3/sel-8, which encode homologs of ERK/MAPK and core components of the Notch-dependent transcription complex, respectively. We use single-molecule FISH (smFISH) and MATLAB to visualize and quantify nuclear nascent transcripts and cytoplasmic mRNAs as a function of position along the germline developmental axis. Using differentially labeled probes, one spanning an exceptionally long first intron and the other spanning exons, we identify two classes of active transcription sites (ATS). The iATS class, for "incomplete" ATS, harbors only partial nascent transcripts; the cATS class, for "complete" ATS, harbors full-length nascent transcripts. Remarkably, the frequencies of iATS and cATS are patterned along the germline axis. For example, most mpk-1 ATS are iATS in hermaphrodite germline stem cells, but most are cATS in differentiating stem cell daughters. Thus, mpk-1 ATS class frequencies switch in a graded manner as stem cell daughters begin differentiation. Importantly, the patterns of ATS class frequency are gene-, stage-, and sex-specific, and cATS frequency strongly correlates with transcriptional output. Although the molecular mechanism underlying ATS classes is not understood, their primary difference is the extent of transcriptional progression. To generate only partial nascent transcripts in iATS, progression must be slowed, paused, or aborted midway through the gene. We propose that regulation of ATS class can be a critical mode of developmental gene regulation.
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Affiliation(s)
| | - John McCloskey
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
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9
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Bagchi D, Mason BD, Baldino K, Li B, Lee EJ, Zhang Y, Chu LK, El Raheb S, Sinha I, Neppl RL. Adult-Onset Myopathy with Constitutive Activation of Akt following the Loss of hnRNP-U. iScience 2020; 23:101319. [PMID: 32659719 PMCID: PMC7358745 DOI: 10.1016/j.isci.2020.101319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/30/2020] [Accepted: 06/24/2020] [Indexed: 01/03/2023] Open
Abstract
Skeletal muscle has the remarkable ability to modulate its mass in response to changes in nutritional input, functional utilization, systemic disease, and age. This is achieved by the coordination of transcriptional and post-transcriptional networks and the signaling cascades balancing anabolic and catabolic processes with energy and nutrient availability. The extent to which alternative splicing regulates these signaling networks is uncertain. Here we investigate the role of the RNA-binding protein hnRNP-U on the expression and splicing of genes and the signaling processes regulating skeletal muscle hypertrophic growth. Muscle-specific Hnrnpu knockout (mKO) mice develop an adult-onset myopathy characterized by the selective atrophy of glycolytic muscle, the constitutive activation of Akt, increases in cellular and metabolic stress gene expression, and changes in the expression and splicing of metabolic and signal transduction genes. These findings link Hnrnpu with the balance between anabolic signaling, cellular and metabolic stress, and physiological growth. Hnrnpu mKO mice develop adult-onset myopathy with selective glycolytic muscle atrophy Akt is constitutively active in the atrophied muscles of Hnrnpu mKO mice Hnrnpu mutants show altered gene expression and alternative splicing patterns Induction of genes associated with cellular and metabolic stress
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Affiliation(s)
- Debalina Bagchi
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Benjamin D Mason
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
| | - Kodilichi Baldino
- Division of Plastic Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Bin Li
- Division of Plastic Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Eun-Joo Lee
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Yuteng Zhang
- Division of Plastic Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Linh Khanh Chu
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
| | - Sherif El Raheb
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
| | - Indranil Sinha
- Division of Plastic Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Ronald L Neppl
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
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10
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Elongin C Contributes to RNA Polymerase II Degradation by the Interferon Antagonist NSs of La Crosse Orthobunyavirus. J Virol 2020; 94:JVI.02134-19. [PMID: 31941775 PMCID: PMC7081911 DOI: 10.1128/jvi.02134-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 12/21/2022] Open
Abstract
The mosquito-borne La Crosse virus (LACV; genus Orthobunyavirus, family Peribunyaviridae, order Bunyavirales) is prevalent in the United States and can cause severe childhood meningoencephalitis. Its main virulence factor, the nonstructural protein NSs, is a strong inhibitor of the antiviral type I interferon (IFN) system. NSs acts by imposing a global host mRNA synthesis shutoff, mediated by NSs-driven proteasomal degradation of the RPB1 subunit of RNA polymerase II. Here, we show that RPB1 degradation commences as early as 1 h postinfection, and identify the E3 ubiquitin ligase subunit Elongin C (and its binding partners Elongins A and B) as an NSs cofactor involved in RPB1 degradation and in suppression of global as well as IFN-related mRNA synthesis. Mosquito-borne La Crosse virus (LACV; genus Orthobunyavirus, family Peribunyaviridae, order Bunyavirales) causes up to 100 annual cases of severe meningoencephalitis in children and young adults in the United States. A major virulence factor of LACV is the nonstructural protein NSs, which inhibits host cell mRNA synthesis to prevent the induction of antiviral type I interferons (IFN-α/β). To achieve this host transcriptional shutoff, LACV NSs drives the proteasomal degradation of RPB1, the large subunit of mammalian RNA polymerase II. Here, we show that NSs acts in a surprisingly rapid manner, as RPB1 degradation was commencing already at 1 h postinfection. The RPB1 degradation was partially dependent on the cellular E3 ubiquitin ligase subunit Elongin C. Consequently, removal of Elongin C, but also of the subunits Elongin A or B by siRNA transfection partially rescued general RNAP II transcription and IFN-beta mRNA synthesis from the blockade by NSs. In line with these results, LACV NSs was found to trigger the redistribution of Elongin C out of nucleolar speckles, which, however, is an epiphenomenon rather than part of the NSs mechanism. Our study also shows that the molecular phenotype of LACV NSs is different from RNA polymerase II inhibitors like α-amanitin or Rift Valley fever virus NSs, indicating that LACV is unique in involving the Elongin complex to shut off host transcription and IFN response. IMPORTANCE The mosquito-borne La Crosse virus (LACV; genus Orthobunyavirus, family Peribunyaviridae, order Bunyavirales) is prevalent in the United States and can cause severe childhood meningoencephalitis. Its main virulence factor, the nonstructural protein NSs, is a strong inhibitor of the antiviral type I interferon (IFN) system. NSs acts by imposing a global host mRNA synthesis shutoff, mediated by NSs-driven proteasomal degradation of the RPB1 subunit of RNA polymerase II. Here, we show that RPB1 degradation commences as early as 1 h postinfection, and identify the E3 ubiquitin ligase subunit Elongin C (and its binding partners Elongins A and B) as an NSs cofactor involved in RPB1 degradation and in suppression of global as well as IFN-related mRNA synthesis.
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11
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Neil CR, Fairbrother WG. Intronic RNA: Ad'junk' mediator of post-transcriptional gene regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194439. [PMID: 31682938 DOI: 10.1016/j.bbagrm.2019.194439] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/30/2019] [Indexed: 01/23/2023]
Abstract
RNA splicing, the process through which intervening segments of noncoding RNA (introns) are excised from pre-mRNAs to allow for the formation of a mature mRNA product, has long been appreciated for its capacity to add complexity to eukaryotic proteomes. However, evidence suggests that the utility of this process extends beyond protein output and provides cells with a dynamic tool for gene regulation. In this review, we aim to highlight the role that intronic RNA plays in mediating specific splicing outcomes in pre-mRNA processing, as well as explore an emerging class of stable intronic sequences that have been observed to act in gene expression control. Building from underlying flexibility in both sequence and structure, intronic RNA provides mechanisms for post-transcriptional gene regulation that are amenable to the tissue and condition specific needs of eukaryotic cells. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Christopher R Neil
- Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States of America
| | - William G Fairbrother
- Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States of America; Center for Computational Molecular Biology, Brown University, Providence, RI, United States of America.
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12
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Pervouchine DD. Circular exonic RNAs: When RNA structure meets topology. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194384. [PMID: 31102674 DOI: 10.1016/j.bbagrm.2019.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022]
Abstract
Although RNA circularization was first documented in the 1990s, the extent to which it occurs was not known until recent advances in high-throughput sequencing enabled the widespread identification of circular RNAs (circRNAs). Despite this, many aspects of circRNA biogenesis, structure, and function yet remain obscure. This review focuses on circular exonic RNAs, a subclass of circRNAs that are generated through backsplicing. Here, I hypothesize that RNA secondary structure can be the common factor that promotes both exon skipping and spliceosomal RNA circularization, and that backsplicing of double-stranded regions could generate topologically linked circRNA molecules. CircRNAs manifest themselves by the presence of tail-to-head exon junctions, which were previously attributed to post-transcriptional exon permutation and repetition. I revisit these observations and argue that backsplicing does not automatically imply RNA circularization because tail-to-head exon junctions give only local information about transcript architecture and, therefore, they are in principle insufficient to determine globally circular topology. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Dmitri D Pervouchine
- Skolkovo Institute of Science and Technology, 3 Nobel St, Moscow 143026, Russia; Faculty of Bioengineering and Bioinformatics, Moscow State University, Leninskiye Gory 1-73, Moscow 119234, Russia.
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Abstract
MicroRNAs (miRNAs), small single-stranded regulatory RNAs capable of interfering with intracellular messenger RNAs (mRNAs) that contain either complete or partial complementarity, are useful for the design of new therapies against cancer polymorphism and viral mutation. Numerous miRNAs have been reported to induce RNA interference (RNAi), a post-transcriptional gene-silencing mechanism. Recent evidence also indicates that they are involved in the transcriptional regulation of genome activities. They were first discovered in Caenorhabditis elegans as native RNA fragments that modulate a wide range of genetic regulatory pathways during embryonic development, and are now recognized as small gene silencers transcribed from the noncoding regions of a genome. In humans, nearly 97% of the genome is noncoding DNA, which varies from one individual to another, and changes in these sequences are frequently noted to manifest in clinical and circumstantial malfunction; for example, type 2 myotonic dystrophy and fragile X syndrome were found to be associated with miRNAs derived from introns. Intronic miRNA is a new class of miRNAs derived from the processing of non-protein-coding regions of gene transcripts. The intronic miRNAs differ uniquely from previously described intergenic miRNAs in the requirement of RNA polymerase (Pol)-II and spliceosomal components for its biogenesis. Several kinds of intronic miRNAs have been identified in C. elegans, mouse, and human cells; however, their functions and applications have not been reported. Here, we show for the first time that intron-derived miRNA is not only able to induce RNAi in mammalian cells but also in fish, chicken embryos, and adult mice cells, demonstrating the evolutionary preservation of this gene regulation system in vivo. These miRNA-mediated animal models provide artificial means to reproduce the mechanisms of miRNA-induced disease in vivo and will shed further light on miRNA-related therapies.
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Affiliation(s)
- Shi-Lung Lin
- Division of Regenerative Medicine, WJWU & LYNN Institute for Stem Cell Research, Santa Fe Springs, CA, USA.
| | - Shao-Yao Ying
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Holdt LM, Kohlmaier A, Teupser D. Molecular functions and specific roles of circRNAs in the cardiovascular system. Noncoding RNA Res 2018; 3:75-98. [PMID: 30159442 PMCID: PMC6096412 DOI: 10.1016/j.ncrna.2018.05.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 05/11/2018] [Accepted: 05/11/2018] [Indexed: 12/25/2022] Open
Abstract
As part of the superfamily of long noncoding RNAs, circular RNAs (circRNAs) are emerging as a new type of regulatory molecules that partake in gene expression control. Here, we review the current knowledge about circRNAs in cardiovascular disease. CircRNAs are not only associated with different types of cardiovascular disease, but they have also been identified as intracellular effector molecules for pathophysiological changes in cardiovascular tissues, and as cardiovascular biomarkers. This evidence is put in the context of the current understanding of general circRNA biogenesis and of known interactions of circRNAs with DNA, RNA, and proteins.
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Affiliation(s)
- Lesca M. Holdt
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Germany
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15
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Holdt LM, Kohlmaier A, Teupser D. Molecular roles and function of circular RNAs in eukaryotic cells. Cell Mol Life Sci 2018; 75:1071-1098. [PMID: 29116363 PMCID: PMC5814467 DOI: 10.1007/s00018-017-2688-5] [Citation(s) in RCA: 239] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/29/2017] [Accepted: 10/17/2017] [Indexed: 12/27/2022]
Abstract
Protein-coding and noncoding genes in eukaryotes are typically expressed as linear messenger RNAs, with exons arranged colinearly to their genomic order. Recent advances in sequencing and in mapping RNA reads to reference genomes have revealed that thousands of genes express also covalently closed circular RNAs. Many of these circRNAs are stable and contain exons, but are not translated into proteins. Here, we review the emerging understanding that both, circRNAs produced by co- and posttranscriptional head-to-tail "backsplicing" of a downstream splice donor to a more upstream splice acceptor, as well as circRNAs generated from intronic lariats during colinear splicing, may exhibit physiologically relevant regulatory functions in eukaryotes. We describe how circRNAs impact gene expression of their host gene locus by affecting transcriptional initiation and elongation or splicing, and how they partake in controlling the function of other molecules, for example by interacting with microRNAs and proteins. We conclude with an outlook how circRNA dysregulation affects disease, and how the stability of circRNAs might be exploited in biomedical applications.
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Affiliation(s)
- Lesca M Holdt
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.
| | - Alexander Kohlmaier
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
- Faculty of Biology, Genetics, LMU Munich, Großhaderner Str. 2-4, 82152, Martinsried, Germany
| | - Daniel Teupser
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
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16
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Abstract
Transgenic animal models are valuable tools for testing gene functions and drug mechanisms in vivo. They are also the best similitude for a human body for etiological and pathological research of diseases. All pharmaceutically developed medicines must be proven to be safe and effective in animals before approval by the Food and Drug Administration (FDA) to be used in clinical trials. To this end, the transgenic animal models of diseases serve as the front line of drug evaluation. However, there is currently no transgenic animal model for microRNA (miRNA)-related research. MiRNAs, small single-stranded regulatory RNAs capable of silencing intracellular gene transcripts (mRNAs) that contain either complete or partial complementarity to the miRNA, are useful for the design of new therapies against cancer polymorphism and viral mutation. Recently, varieties of natural miRNAs have been found to be derived from hairpin-like RNA precursors in almost all eukaryotes, including yeast (Schizosaccharomyces pombe), plant (Arabidopsis spp.), nematode (Caenorhabditis elegans), fly (Drosophila melanogaster), fish, mouse and human, involving intracellular defense against viral infections and regulation of certain gene expressions during development. To facilitate the miRNA research in vivo, we have developed a state-of-the-art transgenic strategy for silencing specific genes in zebrafish, chicken, and mouse, using intronic miRNAs. By the insertion of a hairpin-like pre-miRNA structure into the intron region of a gene, we have found that mature miRNAs were successfully transcribed by RNA polymerases type II (Pol-II), coexpressed with the encoding gene transcripts, and excised out of the encoding gene transcripts by intracellular RNA splicing and processing mechanisms. In conjunction with retroviral transfection, the designed hairpin-like pre-miRNA construct has also been placed in the intron regions of a cellular gene for tissue-specific expression, specifically regulated by the gene promoter of interest. Because the retroviral vectors are integrated into the genome of its host cells, we can select and propagate the most effective transgenic animals to form a stable model line for further research. Here, we have shown for the first time that transgene-like animal models were generated using the intronic miRNA expression system reported previously, which has been proven to be useful for studying miRNA function as well as the related gene regulation in vivo.
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Affiliation(s)
- Shi-Lung Lin
- Division of Regenerative Medicine, WJWU & LYNN Institute for Stem Cell Research, Santa Fe Springs, CA, USA.
| | - Shin-Ju E Chang
- Division of Regenerative Medicine, WJWU & LYNN Institute for Stem Cell Research, Santa Fe Springs, CA, USA
| | - Shao-Yao Ying
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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17
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Nowak CM, Lawson S, Zerez M, Bleris L. Guide RNA engineering for versatile Cas9 functionality. Nucleic Acids Res 2016; 44:9555-9564. [PMID: 27733506 PMCID: PMC5175371 DOI: 10.1093/nar/gkw908] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/23/2016] [Accepted: 10/03/2016] [Indexed: 12/16/2022] Open
Abstract
The Clustered Regularly Interspaced Short Palindromic Repeats system allows a single guide RNA (sgRNA) to direct a protein with combined helicase and nuclease activity to the DNA. Streptococcus pyogenes Cas9 (SpCas9), a CRISPR-associated protein, has revolutionized our ability to probe and edit the human genome in vitro and in vivo Arguably, the true modularity of the Cas9 platform is conferred through the ease of sgRNA programmability as well as the degree of modifications the sgRNA can tolerate without compromising its association with SpCas9 and function. In this review, we focus on the properties and recent engineering advances of the sgRNA component in Cas9-mediated genome targeting.
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Affiliation(s)
- Chance M Nowak
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Seth Lawson
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Megan Zerez
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Leonidas Bleris
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX 75080, USA
- Bioengineering Department, The University of Texas at Dallas, Richardson, TX 75080, USA
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18
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Osman I, Tay MLI, Pek JW. Stable intronic sequence RNAs (sisRNAs): a new layer of gene regulation. Cell Mol Life Sci 2016; 73:3507-19. [PMID: 27147469 PMCID: PMC11108444 DOI: 10.1007/s00018-016-2256-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 02/05/2023]
Abstract
Upon splicing, introns are rapidly degraded. Hence, RNAs derived from introns are commonly deemed as junk sequences. However, the discoveries of intronic-derived small nucleolar RNAs (snoRNAs), small Cajal body associated RNAs (scaRNAs) and microRNAs (miRNAs) suggested otherwise. These non-coding RNAs are shown to play various roles in gene regulation. In this review, we highlight another class of intron-derived RNAs known as stable intronic sequence RNAs (sisRNAs). sisRNAs have been observed since the 1980 s; however, we are only beginning to understand their biological significance. Recent studies have shown or suggested that sisRNAs regulate their own host's gene expression, function as molecular sinks or sponges, and regulate protein translation. We propose that sisRNAs function as an additional layer of gene regulation in the cells.
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Affiliation(s)
- Ismail Osman
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Mandy Li-Ian Tay
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Jun Wei Pek
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore.
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19
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Bhalla N, Sun C, Metthew Lam LK, Gardner CL, Ryman KD, Klimstra WB. Host translation shutoff mediated by non-structural protein 2 is a critical factor in the antiviral state resistance of Venezuelan equine encephalitis virus. Virology 2016; 496:147-165. [PMID: 27318152 PMCID: PMC5821108 DOI: 10.1016/j.virol.2016.06.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/06/2016] [Accepted: 06/08/2016] [Indexed: 10/21/2022]
Abstract
Most previous studies of interferon-alpha/beta (IFN-α/β) response antagonism by alphaviruses have focused upon interruption of IFN-α/β induction and/or receptor signaling cascades. Infection of mice with Venezuelan equine encephalitis alphavirus (VEEV) or Sindbis virus (SINV) induces serum IFN-α/β, that elicits a systemic antiviral state in uninfected cells successfully controlling SINV but not VEEV replication. Furthermore, VEEV replication is more resistant than that of SINV to a pre-existing antiviral state in vitro. While host macromolecular shutoff is proposed as a major antagonist of IFN-α/β induction, the underlying mechanisms of alphavirus resistance to a pre-existing antiviral state are not fully defined, nor is the mechanism for the greater resistance of VEEV. Here, we have separated viral transcription and translation shutoff with multiple alphaviruses, identified the viral proteins that induce each activity, and demonstrated that VEEV nonstructural protein 2-induced translation shutoff is likely a critical factor in enhanced antiviral state resistance of this alphavirus.
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Affiliation(s)
- Nishank Bhalla
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Chengqun Sun
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - L K Metthew Lam
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Christina L Gardner
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kate D Ryman
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - William B Klimstra
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States.
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20
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Pek JW, Osman I, Tay MLI, Zheng RT. Stable intronic sequence RNAs have possible regulatory roles in Drosophila melanogaster. J Cell Biol 2016; 211:243-51. [PMID: 26504165 PMCID: PMC4621838 DOI: 10.1083/jcb.201507065] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Stable intronic sequence RNAs (sisRNAs) are present in Drosophila melanogaster, and a sisRNA modulates its host gene expression by repressing a long noncoding RNA during embryogenesis. Stable intronic sequence RNAs (sisRNAs) have been found in Xenopus tropicalis, human cell lines, and Epstein-Barr virus; however, the biological significance of sisRNAs remains poorly understood. We identify sisRNAs in Drosophila melanogaster by deep sequencing, reverse transcription polymerase chain reaction, and Northern blotting. We characterize a sisRNA (sisR-1) from the regena (rga) locus and show that it can be processed from the precursor messenger RNA (pre-mRNA). We also document a cis-natural antisense transcript (ASTR) from the rga locus, which is highly expressed in early embryos. During embryogenesis, ASTR promotes robust rga pre-mRNA expression. Interestingly, sisR-1 represses ASTR, with consequential effects on rga pre-mRNA expression. Our results suggest a model in which sisR-1 modulates its host gene expression by repressing ASTR during embryogenesis. We propose that sisR-1 belongs to a class of sisRNAs with probable regulatory activities in Drosophila.
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Affiliation(s)
- Jun Wei Pek
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604
| | - Ismail Osman
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604
| | - Mandy Li-Ian Tay
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604
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21
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Minor Contribution of Chimeric Host-HIV Readthrough Transcripts to the Level of HIV Cell-Associated gag RNA. J Virol 2015; 90:1148-51. [PMID: 26559833 DOI: 10.1128/jvi.02597-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/03/2015] [Indexed: 11/20/2022] Open
Abstract
Cell-associated HIV unspliced RNA is an important marker of the viral reservoir. HIV gag RNA-specific assays are frequently used to monitor reservoir activation. Because HIV preferentially integrates into actively transcribed genes, some of the transcripts detected by these assays may not represent genuine HIV RNA but rather chimeric host-HIV readthrough transcripts. Here, we demonstrate that in HIV-infected patients on suppressive combination antiretroviral therapy, such host-derived transcripts do not significantly contribute to the HIV gag RNA level.
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22
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Pek JW, Okamura K. Regulatory RNAs discovered in unexpected places. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:671-86. [DOI: 10.1002/wrna.1309] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/14/2015] [Accepted: 08/21/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Jun Wei Pek
- Temasek Life Sciences Laboratory; 1 Research Link, National University of Singapore; Singapore Singapore
| | - Katsutomo Okamura
- Temasek Life Sciences Laboratory; 1 Research Link, National University of Singapore; Singapore Singapore
- School of Biological Sciences; Nanyang Technological University; Singapore Singapore
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23
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Deng JH, Deng P, Lin SL, Ying SY. Gene silencing in vitro and in vivo using intronic microRNAs. Methods Mol Biol 2015; 1218:321-40. [PMID: 25319661 DOI: 10.1007/978-1-4939-1538-5_20] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
MicroRNAs (miRNAs) are small, single-stranded noncoding RNAs important in many biological processes through posttranscriptional modification of complementary intracellular messenger RNAs (mRNAs). MiRNAs have been reported to induce RNA interference (RNAi), by utilizing the miRNA-induced silencing complex (miRISC) to target mRNAs. They were first discovered in Caenorhabditis elegans as native RNA fragments that modulate a wide range of genetic regulatory pathways during embryonic development, and are now recognized as small gene silencers transcribed from the noncoding regions of a genome. In humans, nearly 97 % of the genome is noncoding DNA and changes in these sequences are frequently noted to manifest in clinical and circumstantial malfunction; for example, type 2 myotonic dystrophy and fragile X syndrome were found to be associated with miRNAs derived from introns. Intronic miRNA (mirtrons) is a class of miRNAs derived from the processing of non-protein-coding regions of gene transcripts. The intronic miRNAs differ uniquely from previously described intergenic miRNAs in the requirement of RNA polymerase (Pol)-II and spliceosomal components for its biogenesis. Several kinds of intronic miRNAs have been identified in C. elegans, mouse, and human cells; however, their functions and applications have not been reported. It is notable that there are different, but still highly conserved, mirtrons in mammalian than in invertebrates, and could be an indication that mirtrons are an evolutionary precursor to existing miRNA biogenesis pathways. Here, we show that intron-derived miRNA is not only able to induce RNAi in mammalian cells but also in fish, chicken embryos, and adult mice cells, demonstrating the evolutionary preservation of this gene regulation system in vivo. These miRNA-mediated animal models provide artificial means to reproduce the mechanisms of miRNA-induced disease in vivo and will shed further light on miRNA-related therapies.
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Affiliation(s)
- Jia Han Deng
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Bishop Medical Teaching and Research Building 401, MCH51A, 1333 San Pablo Street, BMT-301, Los Angeles, CA, 90033, USA
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24
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Talhouarne GJS, Gall JG. Lariat intronic RNAs in the cytoplasm of Xenopus tropicalis oocytes. RNA (NEW YORK, N.Y.) 2014; 20:1476-87. [PMID: 25051970 PMCID: PMC4138330 DOI: 10.1261/rna.045781.114] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We previously demonstrated that the oocyte nucleus (germinal vesicle or GV) of Xenopus tropicalis contains a population of stable RNA molecules derived from the introns of most expressed genes. Here we show that similar stable intronic sequence (sis) RNAs occur in the oocyte cytoplasm. About 9000 cytoplasmic sisRNAs have been identified, all of which are resistant to the exonuclease RNase R. About half have been confirmed as lariat molecules and the rest are presumed to be lariats, whereas nuclear sisRNAs are a mixture of lariat and linear molecules. Cytoplasmic sisRNAs are more abundant on a molar basis than nuclear sisRNAs and are derived from short introns, mostly under 1 kb in length. Both nuclear and cytoplasmic sisRNAs are transmitted intact to the egg at GV breakdown and persist until at least the blastula stage of embryogenesis, when zygotic transcription begins. We compared cytoplasmic sisRNAs derived from orthologous genes of X. tropicalis and X. laevis, and found that the specific introns from which sisRNAs are derived are not conserved. The existence of sisRNAs in the cytoplasm of the oocyte, their transmission to the fertilized egg, and their persistence during early embryogenesis suggest that they might play a regulatory role in mRNA translation.
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Affiliation(s)
- Gaëlle J S Talhouarne
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA Department of Biology, Mudd Hall, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Joseph G Gall
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA Department of Biology, Mudd Hall, Johns Hopkins University, Baltimore, Maryland 21218, USA
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25
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Nissim L, Perli SD, Fridkin A, Perez-Pinera P, Lu TK. Multiplexed and programmable regulation of gene networks with an integrated RNA and CRISPR/Cas toolkit in human cells. Mol Cell 2014; 54:698-710. [PMID: 24837679 PMCID: PMC4077618 DOI: 10.1016/j.molcel.2014.04.022] [Citation(s) in RCA: 304] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 04/15/2014] [Accepted: 04/18/2014] [Indexed: 01/23/2023]
Abstract
RNA-based regulation and CRISPR/Cas transcription factors (CRISPR-TFs) have the potential to be integrated for the tunable modulation of gene networks. A major limitation of this methodology is that guide RNAs (gRNAs) for CRISPR-TFs can only be expressed from RNA polymerase III promoters in human cells, limiting their use for conditional gene regulation. We present new strategies that enable expression of functional gRNAs from RNA polymerase II promoters and multiplexed production of proteins and gRNAs from a single transcript in human cells. We use multiple RNA regulatory strategies, including RNA-triple-helix structures, introns, microRNAs, and ribozymes, with Cas9-based CRISPR-TFs and Cas6/Csy4-based RNA processing. Using these tools, we efficiently modulate endogenous promoters and implement tunable synthetic circuits, including multistage cascades and RNA-dependent networks that can be rewired with Csy4 to achieve complex behaviors. This toolkit can be used for programming scalable gene circuits and perturbing endogenous networks for biology, therapeutic, and synthetic biology applications.
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Affiliation(s)
- Lior Nissim
- Synthetic Biology Group, Research Laboratory of Electronics, Department of Biological Engineering and Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Samuel D Perli
- Synthetic Biology Group, Research Laboratory of Electronics, Department of Biological Engineering and Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Alexandra Fridkin
- Synthetic Biology Group, Research Laboratory of Electronics, Department of Biological Engineering and Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Pablo Perez-Pinera
- Synthetic Biology Group, Research Laboratory of Electronics, Department of Biological Engineering and Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Timothy K Lu
- Synthetic Biology Group, Research Laboratory of Electronics, Department of Biological Engineering and Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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An intronic miRNA regulates expression of the human endothelial nitric oxide synthase gene and proliferation of endothelial cells by a mechanism related to the transcription factor SP-1. PLoS One 2013; 8:e70658. [PMID: 23940615 PMCID: PMC3734264 DOI: 10.1371/journal.pone.0070658] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 06/20/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This study was to investigate the molecular mechanisms underlying the 27nt-miRNA-mediated regulation of expression of the endothelial nitric oxide synthase (eNOS) gene. METHODS Cell lines overexpressing 27nt-miRNA or its mutant were established by transfecting the miRNA expression vector into the endothelial cells. eNOS mRNA and protein expression were examined by RT-PCR and Western Blotting, respectively. Luciferase activity reporter system was used to study the target of 27nt-miRNA. RESULTS The results showed that overexpression of 27nt-miRNA significantly inhibited eNOS mRNA level and protein expression, and reduced the eNOS transcriptional efficiency. Such inhibitory effects of 27nt-miRNA were attenuated by the sequence mutations in 27nt-miRNA. Interestingly, the transcription factor SP-1 expression was reduced by 27nt-miRNA. Meanwhile, overxpression of SP-1 protein partially restored eNOS expression, and rescued the 27nt-miRNA-mediated reduction of endothelial cell proliferation. Moreover, certain sites in the SP-1 mRNA were found to be the direct target of 27nt-miRNA by a luciferase reporter system. CONCLUSIONS These results demonstrate that the 27nt-miRNA suppresses eNOS gene expression and SP-1 expression in vascular endothelial cells. The 27nt-miRNA directly target to SP-1 mRNA, thereby contributing to proliferation of endothelial cells.
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27
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Hesselberth JR. Lives that introns lead after splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:677-91. [DOI: 10.1002/wrna.1187] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 06/14/2013] [Accepted: 06/18/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Jay R. Hesselberth
- Department of Biochemistry and Molecular Genetics; University of Colorado Anschutz Medical School; Aurora CO USA
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28
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Lariat sequencing in a unicellular yeast identifies regulated alternative splicing of exons that are evolutionarily conserved with humans. Proc Natl Acad Sci U S A 2013; 110:12762-7. [PMID: 23861491 DOI: 10.1073/pnas.1218353110] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alternative splicing is a potent regulator of gene expression that vastly increases proteomic diversity in multicellular eukaryotes and is associated with organismal complexity. Although alternative splicing is widespread in vertebrates, little is known about the evolutionary origins of this process, in part because of the absence of phylogenetically conserved events that cross major eukaryotic clades. Here we describe a lariat-sequencing approach, which offers high sensitivity for detecting splicing events, and its application to the unicellular fungus, Schizosaccharomyces pombe, an organism that shares many of the hallmarks of alternative splicing in mammalian systems but for which no previous examples of exon-skipping had been demonstrated. Over 200 previously unannotated splicing events were identified, including examples of regulated alternative splicing. Remarkably, an evolutionary analysis of four of the exons identified here as subject to skipping in S. pombe reveals high sequence conservation and perfect length conservation with their homologs in scores of plants, animals, and fungi. Moreover, alternative splicing of two of these exons have been documented in multiple vertebrate organisms, making these the first demonstrations of identical alternative-splicing patterns in species that are separated by over 1 billion y of evolution.
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29
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Gardner EJ, Nizami ZF, Talbot CC, Gall JG. Stable intronic sequence RNA (sisRNA), a new class of noncoding RNA from the oocyte nucleus of Xenopus tropicalis. Genes Dev 2013; 26:2550-9. [PMID: 23154985 DOI: 10.1101/gad.202184.112] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To compare nuclear and cytoplasmic RNA from a single cell type, free of cross-contamination, we studied the oocyte of the frog Xenopus tropicalis, a giant cell with an equally giant nucleus. We isolated RNA from manually dissected nuclei and cytoplasm of mature oocytes and subjected it to deep sequencing. Cytoplasmic mRNA consisted primarily of spliced exons derived from ∼6700 annotated genes. Nearly all of these genes were represented in the nucleus by intronic sequences. However, unspliced nascent transcripts were not detected. Inhibition of transcription or splicing for 1-2 d had little or no effect on the abundance of nuclear intronic sequences, demonstrating that they are unusually stable. RT-PCR analysis showed that these stable intronic sequences are transcribed from the coding strand and that a given intron can be processed into more than one molecule. Stable intronic sequence RNA (sisRNA) from the oocyte nucleus constitutes a new class of noncoding RNA. sisRNA is detectable by RT-PCR in samples of total RNA from embryos up to the mid-blastula stage, when zygotic transcription begins. Storage of sisRNA in the oocyte nucleus and its transmission to the developing embryo suggest that it may play important regulatory roles during oogenesis and/or early embryogenesis.
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Affiliation(s)
- Eugene J Gardner
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
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Abstract
Transgenic animal models are valuable tools for testing gene functions and drug mechanisms in vivo. They are also the best similitude for a human body for etiological and pathological research of diseases. All pharmaceutically developed drugs must be proven to be safe and effective in animals before approval by the Food and Drug Administration to be used in clinical trials. To this end, the transgenic animal models of diseases serve as the front line of drug evaluation. However, there is currently no transgenic animal model for microRNA (miRNA) research. miRNAs, small single-stranded regulatory RNAs capable of silencing intracellular gene transcripts (mRNAs) that contain either complete or partial complementarity to the miRNA, are useful for the design of new therapies against cancer polymorphism and viral mutation. Recently, varieties of natural miRNAs have been found to derived from hairpin-like RNA precursors in almost all eukaryotes, including yeast (Schizosaccharomyces pombe), plant (Arabidopsis spp.), nematode (Caenorhabditis elegans), fly (Drosophila melanogaster), fish, mouse, and human, involving intracellular defense against viral infections and regulation of certain gene expressions during development. To facilitate the miRNA research in vivo, we have developed a state-of-the-art transgenic strategy for silencing specific genes in zebrafish, chicken, and mouse, using intronic miRNAs. By insertion of a hairpin-like pre-miRNA structure into the intron region of a gene, we have found that mature miRNAs were successfully transcribed by RNA polymerases type II (Pol II), coexpressed with the encoding gene transcript, and excised out of the encoding gene transcript by natural RNA splicing and processing mechanisms. In conjunction with retroviral transfection systems, the designed hairpin-like pre-miRNA construct was further tested to insert into the intron regions of a cellular gene for tissue-specific expression regulated by the gene promoter. Because the retroviral vectors were randomly integrated into the genome of its host cell, the most effective transgenic animal can be selected and propagated to be a stable transgenic line for future research. Here, we have shown for the first time that transgene-like animal models were generated using the intronic miRNA-expressing system described previously, which has been proven to be useful for both miRNA research and in vivo evaluation of miRNA-associated target gene functions.
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Affiliation(s)
- Shi-Lung Lin
- Division of Regenerative Medicine, WJWU and LYNN Institute for Stem Cell Research, Santa Fe Springs, CA, USA.
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31
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Abstract
MicroRNAs (miRNAs), small single-stranded regulatory RNAs capable of interfering with intracellular messenger RNAs (mRNAs) that contain either complete or partial complementarity, are useful for the design of new therapies against cancer polymorphism and viral mutation. Numerous miRNAs have been reported to induce RNA interference (RNAi), a posttranscriptional gene-silencing mechanism. Recent evidence also indicates that they are involved in the transcriptional regulation of genome activities. They were first discovered in Caenorhabditis elegans as native RNA fragments that modulate a wide range of genetic regulatory pathways during embryonic development and are now recognized as small gene silencers transcribed from the noncoding regions of a genome. In humans, nearly 97% of the genome is noncoding DNA, which varies from one individual to another, and changes in these sequences are frequently noted to manifest in clinical and circumstantial malfunction; for example, type 2 myotonic dystrophy and fragile X syndrome were found to be associated with miRNAs derived from introns. Intronic miRNA is a new class of miRNAs derived from the processing of nonprotein-coding regions of gene transcripts. The intronic miRNAs differ uniquely from previously described intergenic miRNAs in the requirement of RNA polymerase (Pol)-II and spliceosomal components for its biogenesis. Several kinds of intronic miRNAs have been identified in C. elegans, mouse, and human cells; however, their functions and applications have not been reported. Here, we show for the first time that intron-derived miRNA is not only able to induce RNAi in mammalian cells, but also in fish, chicken embryos, and adult mice cells, demonstrating the evolutionary preservation of this gene regulation system in vivo. These miRNA-mediated animal models provide artificial means to reproduce the mechanisms of miRNA-induced disease in vivo and will shed further light on miRNA-related therapies.
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Affiliation(s)
- Shi-Lung Lin
- Division of Regenerative Medicine, WJWU and LYNN Institute for Stem Cell Research, Santa Fe Springs, CA, USA.
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32
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Yang Y, Pu XD, Qing K, Guo XR, Zhou XY, Zhou XG. Identification of differentially expressed microRNAs and the possible role of miRNA-126* in Sprague-Dawley rats during fetal lung development. Mol Med Rep 2012; 7:65-72. [PMID: 23076204 DOI: 10.3892/mmr.2012.1130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 10/05/2012] [Indexed: 11/05/2022] Open
Abstract
The aim of this study was to conduct a search for microRNAs (miRNAs) that are significant in fetal lung develop-ment to lay a foundation for further studies in the relevant fields. In this study, histological observation was performed in rats by hematoxylin and eosin (H&E) staining at three time points of fetal lung development [Embryo 21 (E21), E19 and E16, and designated as groups S1, S2 and S3, respectively]. An expression profile for fetal lung development was determined using the latest microarray technology. Furthermore, certain differentially expressed miRNAs were selected for further study by real‑time PCR. In total, 202 differentially expressed miRNAs were identified. Among them, miRNA-126* was selected for further study and validated by real-time PCR due to its higher expression levels in the microarrays. The results revealed that the relative expression of miRNA-126* differentially increased as embyronic development increased (P<0.05), which was consistent with the microarray results. In conclusion, we hypothesize that these newly identified miRNAs (including miRNA-126*) may be important in the physiological mechanisms during fetal lung development. These results may aid future studies of neonatal lung development.
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Affiliation(s)
- Yang Yang
- Department of Neonates, Nanjing Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu 210008, PR China.
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33
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Sowa N, Horie T, Kuwabara Y, Baba O, Watanabe S, Nishi H, Kinoshita M, Takanabe‐Mori R, Wada H, Shimatsu A, Hasegawa K, Kimura T, Ono K. MicroRNA 26b encoded by the intron of small CTD phosphatase (SCP) 1 has an antagonistic effect on its host gene. J Cell Biochem 2012; 113:3455-65. [DOI: 10.1002/jcb.24222] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Naoya Sowa
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Takahiro Horie
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Yasuhide Kuwabara
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Osamu Baba
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Shin Watanabe
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Hitoo Nishi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Minako Kinoshita
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Rieko Takanabe‐Mori
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto 612‐8555, Japan
| | - Hiromichi Wada
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto 612‐8555, Japan
| | - Akira Shimatsu
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto 612‐8555, Japan
| | - Koji Hasegawa
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto 612‐8555, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
| | - Koh Ono
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606‐8507, Japan
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34
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Windhager L, Bonfert T, Burger K, Ruzsics Z, Krebs S, Kaufmann S, Malterer G, L'Hernault A, Schilhabel M, Schreiber S, Rosenstiel P, Zimmer R, Eick D, Friedel CC, Dölken L. Ultrashort and progressive 4sU-tagging reveals key characteristics of RNA processing at nucleotide resolution. Genome Res 2012; 22:2031-42. [PMID: 22539649 PMCID: PMC3460197 DOI: 10.1101/gr.131847.111] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
RNA synthesis and decay rates determine the steady-state levels of cellular RNAs. Metabolic tagging of newly transcribed RNA by 4-thiouridine (4sU) can reveal the relative contributions of RNA synthesis and decay rates. The kinetics of RNA processing, however, had so far remained unresolved. Here, we show that ultrashort 4sU-tagging not only provides snapshot pictures of eukaryotic gene expression but, when combined with progressive 4sU-tagging and RNA-seq, reveals global RNA processing kinetics at nucleotide resolution. Using this method, we identified classes of rapidly and slowly spliced/degraded introns. Interestingly, each class of splicing kinetics was characterized by a distinct association with intron length, gene length, and splice site strength. For a large group of introns, we also observed long lasting retention in the primary transcript, but efficient secondary splicing or degradation at later time points. Finally, we show that processing of most, but not all small nucleolar (sno)RNA-containing introns is remarkably inefficient with the majority of introns being spliced and degraded rather than processed into mature snoRNAs. In summary, our study yields unparalleled insights into the kinetics of RNA processing and provides the tools to study molecular mechanisms of RNA processing and their contribution to the regulation of gene expression.
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Affiliation(s)
- Lukas Windhager
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333, Germany
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Kortenoeven MLA, Schweer H, Cox R, Wetzels JFM, Deen PMT. Lithium reduces aquaporin-2 transcription independent of prostaglandins. Am J Physiol Cell Physiol 2011; 302:C131-40. [PMID: 21881002 DOI: 10.1152/ajpcell.00197.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Vasopressin (AVP)-stimulated translocation and transcription of aquaporin-2 (AQP2) water channels in renal principal cells is essential for urine concentration. Twenty percent of patients treated with lithium develop nephrogenic diabetes insipidus (NDI), a disorder in which the kidney is unable to concentrate urine. In vivo and in mouse collecting duct (mpkCCD) cells, lithium treatment coincides with decreased AQP2 abundance and inactivation of glycogen synthase kinase (Gsk) 3β. This is paralleled in vivo by an increased renal cyclooxygenase 2 (COX-2) expression and urinary prostaglandin PGE(2) excretion. PGE(2) reduces AVP-stimulated water reabsorption, but its precise role in lithium-induced downregulation of AQP2 is unclear. Using mpkCCD cells, we here investigated whether prostaglandins contribute to lithium-induced downregulation of AQP2. In these cells, lithium application reduced AQP2 abundance, which coincided with Gsk3β inactivation and increased COX-2 expression. Inhibition of COX by indomethacin, leading to reduced PGE(2) and PGF(2α) levels, or dexamethasone-induced downregulation of COX-2 both increased AQP2 abundance, while PGE(2) addition reduced AQP2 abundance. However, lithium did not change the prostaglandin levels, and indomethacin and dexamethasone did not prevent lithium-induced AQP2 downregulation. Further analysis revealed that lithium decreased AQP2 protein abundance, mRNA levels and transcription, while PGE(2) reduced AQP2 abundance by increasing its lysosomal degradation, but not by reducing AQP2 gene transcription. In conclusion, our data reveal that in mpkCCD cells, prostaglandins decrease AQP2 protein stability by increasing its lysosomal degradation, indicating that in vivo paracrine-produced prostaglandins might have a role in lithium-induced NDI via this mechanism. However, lithium affects also AQP2 gene transcription, which is prostaglandin independent.
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36
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Yan L, Hao H, Elton TS, Liu Z, Ou H. Intronic microRNA suppresses endothelial nitric oxide synthase expression and endothelial cell proliferation via inhibition of STAT3 signaling. Mol Cell Biochem 2011; 357:9-19. [PMID: 21611796 DOI: 10.1007/s11010-011-0870-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 05/06/2011] [Indexed: 01/08/2023]
Abstract
Intronic microRNA (miRNAs) suppressed the expression of endothelial nitric oxide synthase (eNOS) gene in endothelial cells (ECs). This study was to investigate the role of signal transducer and activator of transcription 3 (STAT3) in the regulation of eNOS expression and vascular EC proliferation by the intronic 27-nucleotide (nt) miRNA derived from the 27-base pair repeats in intron 4 of eNOS gene. A detectable level of the 27-nt miRNA was present in the control ECs. Overexpression of the 27-nt miRNA dramatically suppressed the expression of eNOS and STAT3 at both transcription and translation levels in ECs in association with significant inhibition of EC proliferation. Mutation of the 27-nt miRNA at the 3'-terminal region resulted in substantial reduction of the inhibitory effect of miRNA on eNOS and STAT3 expression, and EC proliferation. Overexpression of active STAT3 significantly reversed the inhibitory effect of the 27-nt miRNA on eNOS expression and EC proliferation. In summary, we demonstrated that the 27-nt intronic miRNA functioned as a negative regulator for the expression of its host gene eNOS and cell proliferation in ECs. The sequence in 3'-terminal region played a key role in the function of the 27-nt miRNA. The regulatory effect of the intronic miRNA on eNOS gene expression was associated with miRNA polymorphisms, and mediated through inhibition of STAT3 signaling in ECs.
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Affiliation(s)
- Limei Yan
- Center of Biochemistry Research, University of South China, Hengyang, Hunan 421001, People's Republic of China
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37
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Rabani M, Levin JZ, Fan L, Adiconis X, Raychowdhury R, Garber M, Gnirke A, Nusbaum C, Hacohen N, Friedman N, Amit I, Regev A. Metabolic labeling of RNA uncovers principles of RNA production and degradation dynamics in mammalian cells. Nat Biotechnol 2011; 29:436-42. [PMID: 21516085 PMCID: PMC3114636 DOI: 10.1038/nbt.1861] [Citation(s) in RCA: 415] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 04/01/2011] [Indexed: 12/25/2022]
Abstract
Cellular RNA levels are determined by the interplay of RNA production, processing and degradation. However, because most studies of RNA regulation do not distinguish the separate contributions of these processes, little is known about how they are temporally integrated. Here we combine metabolic labeling of RNA at high temporal resolution with advanced RNA quantification and computational modeling to estimate RNA transcription and degradation rates during the response of mouse dendritic cells to lipopolysaccharide. We find that changes in transcription rates determine the majority of temporal changes in RNA levels, but that changes in degradation rates are important for shaping sharp 'peaked' responses. We used sequencing of the newly transcribed RNA population to estimate temporally constant RNA processing and degradation rates genome wide. Degradation rates vary significantly between genes and contribute to the observed differences in the dynamic response. Certain transcripts, including those encoding cytokines and transcription factors, mature faster. Our study provides a quantitative approach to study the integrative process of RNA regulation.
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Affiliation(s)
- Michal Rabani
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
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38
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Abstract
Measurements of changes in pre-mRNA levels by intron-specific probes are generally accepted as more closely reflecting changes in gene transcription rates than are measurements of mRNA levels by exonic probes. This is, in part, because the pre-mRNAs, which include the primary transcript and various splicing intermediates located in the nucleus (also referred to as heteronuclear RNAs, or hnRNAs), are processed rapidly (with half-lives <60 min) as compared to neuropeptide mRNAs, which are then transferred to the cytoplasm and which have much longer half-lives (often over days). In this chapter, we describe the use of exon-and intron-specific probes to evaluate oxytocin (OT) and vasopressin (VP) neuropeptide gene expression by analyses of their mRNAs and hnRNAs by quantitative in situ hybridization (qISH) and also by using specific PCR primers in quantitative, real-time PCR (qPCR) procedures.
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Affiliation(s)
- Harold Gainer
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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39
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Verbruggen P, Ruf M, Blakqori G, Överby AK, Heidemann M, Eick D, Weber F. Interferon antagonist NSs of La Crosse virus triggers a DNA damage response-like degradation of transcribing RNA polymerase II. J Biol Chem 2010; 286:3681-92. [PMID: 21118815 DOI: 10.1074/jbc.m110.154799] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
La Crosse encephalitis virus (LACV) is a mosquito-borne member of the negative-strand RNA virus family Bunyaviridae. We have previously shown that the virulence factor NSs of LACV is an efficient inhibitor of the antiviral type I interferon system. A recombinant virus unable to express NSs (rLACVdelNSs) strongly induced interferon transcription, whereas the corresponding wt virus (rLACV) suppressed it. Here, we show that interferon induction by rLACVdelNSs mainly occurs through the signaling pathway leading from the pattern recognition receptor RIG-I to the transcription factor IRF-3. NSs expressed by rLACV, however, acts downstream of IRF-3 by specifically blocking RNA polymerase II-dependent transcription. Further investigations revealed that NSs induces proteasomal degradation of the mammalian RNA polymerase II subunit RPB1. NSs thereby selectively targets RPB1 molecules of elongating RNA polymerase II complexes, the so-called IIo form. This phenotype has similarities to the cellular DNA damage response, and NSs was indeed found to transactivate the DNA damage response gene pak6. Moreover, NSs expressed by rLACV boosted serine 139 phosphorylation of histone H2A.X, one of the earliest cellular reactions to damaged DNA. However, other DNA damage response markers such as up-regulation and serine 15 phosphorylation of p53 or serine 1524 phosphorylation of BRCA1 were not triggered by LACV infection. Collectively, our data indicate that the strong suppression of interferon induction by LACV NSs is based on a shutdown of RNA polymerase II transcription and that NSs achieves this by exploiting parts of the cellular DNA damage response pathway to degrade IIo-borne RPB1 subunits.
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Affiliation(s)
- Paul Verbruggen
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, D-79008 Freiburg, Germany
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40
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Abstract
Nearly 97% of the human genome is composed of noncoding DNA,
which varies from one species to another. Changes in these
sequences often manifest themselves in clinical and circumstantial
malfunction. Numerous genes in these non-protein-coding regions
encode microRNAs, which are responsible for RNA-mediated
gene silencing through RNA interference (RNAi)-like pathways.
MicroRNAs (miRNAs), small single-stranded regulatory RNAs capable
of interfering with intracellular messenger RNAs (mRNAs) with
complete or partial complementarity, are useful for the design of
new therapies against cancer polymorphisms and viral mutations. Currently, many varieties
of miRNA are widely reported in plants, animals, and even
microbes. Intron-derived microRNA (Id-miRNA) is a new class of
miRNA derived from the processing of gene introns. The intronic
miRNA requires type-II RNA polymerases (Pol-II) and spliceosomal
components for their biogenesis. Several kinds of Id-miRNA have
been identified in C elegans, mouse, and human cells;
however, neither function nor application has been reported. Here,
we show for the first time that intron-derived miRNAs are able to
induce RNA interference in not only human and mouse cells, but in
also zebrafish, chicken embryos, and adult mice, demonstrating the
evolutionary preservation of intron-mediated gene silencing via
functional miRNA in cell and in vivo. These findings suggest an
intracellular miRNA-mediated gene regulatory system, fine-tuning
the degradation of protein-coding messenger RNAs.
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Affiliation(s)
- Shi-Lung Lin
- Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, BMT-403, 1333 San Pablo Street,
Los Angeles, CA 90033, USA
| | - Joseph D. Miller
- Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, BMT-403, 1333 San Pablo Street,
Los Angeles, CA 90033, USA
| | - Shao-Yao Ying
- Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, BMT-403, 1333 San Pablo Street,
Los Angeles, CA 90033, USA
- *Shao-Yao Ying:
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41
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Arancio W. RNA memory model: a RNA-mediated transcriptional activation mechanism involved in cell identity. Rejuvenation Res 2010; 13:365-72. [PMID: 20370500 DOI: 10.1089/rej.2009.0957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
I propose a new model, called the "RNA memory" model, for the possible role of RNAs in the maintenance and establishment of cell identity. This is cytoplasmic memory obtained by the transmission of mother noncoding (nc) RNAs to daughter cells. These RNAs are able to activate transcription via sequence homology in daughter cells. Regulation of RNA memory is strictly linked to the regulation of ncRNAs with repressive features, such as the RNAs involved in RNA interference (RNAi). Misregulation of this system could lead to misidentity, and thus it could be involved in cancer transformation, progression of viral or genetic diseases, and progression of senescence.
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42
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Ying SY, Chang CP, Lin SL. Intron-mediated RNA interference, intronic microRNAs, and applications. Methods Mol Biol 2010; 629:205-37. [PMID: 20387152 DOI: 10.1007/978-1-60761-657-3_14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nearly 97% of the human genome is non-coding DNA. The intron occupies most of it around the gene-coding regions. Numerous intronic sequences have been recently found to encode microRNAs (miRNAs), responsible for RNA-mediated gene silencing through RNA interference (RNAi)-like pathways. miRNAs, small single-stranded regulatory RNAs capable of interfering with intracellular messenger RNAs (mRNAs) that contain either complete or partial complementarity, are useful for the design of new therapies against cancer polymorphism and viral mutation. This flexible characteristic differs from double-stranded siRNAs (small interfering RNAs) because more rigid complementarity is required for siRNA-induced RNAi gene silencing. miRNAs were firstly discovered in Caenorhabditis elegans as native RNA fragments that modulate a wide range of genetic regulatory pathways during embryonic development. Currently, varieties of miRNAs are widely reported in plants, animals, and even microorganisms. Intronic miRNA is a new class of miRNAs derived from the processing of gene introns. The intronic miRNAs differ from previously described intergenic miRNAs due to the requirement of type II RNA polymerases (Pol-II) and spliceosomal components for their biogenesis. Several kinds of intronic miRNAs have been identified in C. elegans, mouse, and human cells. However, neither function nor application has been reported. Here, we show that, for the first time, intron-derived miRNAs are able to induce RNA interference not only in human and mouse cell lines but also in zebrafish, chicken, and mouse, which demonstrates the evolutionary preservation of the intron-mediated gene silencing through miRNA functionality in cell and in vivo. Based on this novel mechanism, numerous biomedical applications have been developed, including cosmetic skin whitening, transgenic animal generation, anti-viral vaccination and therapy, and somatic cell reprogramming into induced pluripotent stem (iPS) cells. These findings suggest an important miRNA-mediated gene regulatory system, which fine-tunes a variety of cellular and developmental events through the mechanism of RNAi-like gene silencing.
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Affiliation(s)
- Shao-Yao Ying
- Department of Cell, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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43
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Mattick JS. Deconstructing the dogma: a new view of the evolution and genetic programming of complex organisms. Ann N Y Acad Sci 2009; 1178:29-46. [PMID: 19845626 DOI: 10.1111/j.1749-6632.2009.04991.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Since the birth of molecular biology it has been generally assumed that most genetic information is transacted by proteins, and that RNA plays an intermediary role. This led to the subsidiary assumption that the vast tracts of noncoding sequences in the genomes of higher organisms are largely nonfunctional, despite the fact that they are transcribed. These assumptions have since become articles of faith, but they are not necessarily correct. I propose an alternative evolutionary history whereby developmental and cognitive complexity has arisen by constructing sophisticated RNA-based regulatory networks that interact with generic effector complexes to control gene expression patterns and the epigenetic trajectories of differentiation and development. Environmental information can also be conveyed into this regulatory system via RNA editing, especially in the brain. Moreover, the observations that RNA-directed epigenetic changes can be inherited raises the intriguing question: has evolution learnt how to learn?
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Affiliation(s)
- John S Mattick
- Institute for Molecular Bioscience, The University of Queensland, St Lucia QLD 4072, Australia.
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44
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Teng G, Papavasiliou FN. Long noncoding RNAs: implications for antigen receptor diversification. Adv Immunol 2009; 104:25-50. [PMID: 20457115 DOI: 10.1016/s0065-2776(08)04002-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Noncoding RNAs (ncRNAs), both small and large, have recently risen to prominence as surprisingly versatile regulators of gene expression. In fact, eukaryotic transcriptomes are rife with RNAs that do not code for protein, though the majority of these species remains wholly uncharacterized. The functional diversity among the mere handful of validated ncRNAs hints at the vast regulatory potential of these silent biomolecules. Though the act of noncoding transcription and the resultant ncRNAs do not directly produce proteins, they represent powerful means of gene control. Here we survey the accumulating literature on the myriad functions of long ncRNAs and emphasize one curious case of noncoding transcription at antigen receptor loci in lymphocytes.
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Affiliation(s)
- Grace Teng
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
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45
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Abstract
Nearly 97% of the human genome is non-coding DNA, and introns occupy most of it around the gene-coding regions. Numerous intronic sequences have been recently found to encode microRNAs, which are responsible for RNA-mediated gene silencing through RNA interference (RNAi)-like pathways. microRNAs (miRNAs), small single-stranded regulatory RNAs capable of interfering with intracellular messenger RNAs (mRNAs) that contain either complete or partial complementarity, are useful for the design of new therapies against cancer polymorphism and viral mutation. This flexible characteristic is different from double-stranded siRNAs (small interfering RNAs) because a much more rigid complementarity is required for siRNA-induced RNAi gene silencing. miRNAs were firstly discovered in Caenorhabditis elegans as native RNA fragments that modulate a wide range of genetic regulatory pathways during embryonic development. Currently, varieties of miRNAs are widely reported in plants, animals and even microbes. Intronic microRNA is a new class of miRNAs derived from the processing of gene introns. The intronic miRNAs differ uniquely from previously described intergenic miRNAs in the requirement of type II RNA polymerases (Pol-II) and spliceosomal components for their biogenesis. Several kinds of intronic miRNAs have been identified in C. elegans, mouse and human cells; however, neither function nor application has been reported. Here, we show for the first time that intron-derived miRNAs are able to induce RNA interference in not only human and mouse cells but also zebrafishes, chicken embryos and adult mice, demonstrating the evolutionary preservation of the intron-mediated gene silencing through miRNA functionality in cell and in vivo. These findings suggest an intracellular miRNA-mediated gene regulatory system, fine-tuning the degradation of protein-coding messenger RNAs.
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46
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Louro R, Smirnova AS, Verjovski-Almeida S. Long intronic noncoding RNA transcription: expression noise or expression choice? Genomics 2008; 93:291-8. [PMID: 19071207 DOI: 10.1016/j.ygeno.2008.11.009] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Accepted: 11/16/2008] [Indexed: 02/07/2023]
Abstract
Recently, it was discovered that non-protein-coding RNAs (ncRNAs) represent the majority of the human transcripts. Regulatory role of many classes of ncRNAs is broadly recognized; however, long intronic ncRNAs have received little attention. In the past few years, evidence that intronic regions are key sources of regulatory ncRNAs has first appeared. Here we present an updated vision of the intronic ncRNA world, giving special attention to the long intronic ncRNAs. We summarize aspects of their expression pattern, evolutionary constraints, biogenesis, and responsiveness to physiological stimuli, and postulate their mechanisms of action. Deciphering nature's choice of different types of messages conveyed by ncRNAs will shed light on the RNA-based layer of regulatory processes in eukaryotic cells.
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Affiliation(s)
- Rodrigo Louro
- Departamento de Bioquimica, Instituto de Quimica, Universidade de São Paulo, 05508-900 São Paulo, SP, Brazil
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47
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Yue C, Ponzio TA, Fields RL, Gainer H. Oxytocin and vasopressin gene expression and RNA splicing patterns in the rat supraoptic nucleus. Physiol Genomics 2008; 35:231-42. [PMID: 18765859 PMCID: PMC2585020 DOI: 10.1152/physiolgenomics.90218.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Accepted: 08/28/2008] [Indexed: 11/22/2022] Open
Abstract
In this study, we test the hypothesis that there are differential splicing patterns between the expressed oxytocin (OT) and vasopressin (VP) genes in the rat supraoptic nucleus (SON). We quantify the low abundance, intron-containing heteronuclear RNAs (hnRNAs) and the higher abundance mRNAs in the SON using two-step, quantitative SYBR Green real-time reverse transcription (RT)-PCR and external standard curves constructed using synthetic 90 nt sense-strand oligonucleotides. The levels of OT and VP mRNA in the SON were found to be similar, approximately 10(8) copies/SON pair, whereas the copy numbers of VP hnRNAs containing intron 1 or 2 and the OT hnRNA containing intron 1 are much lower, i.e., approximately 10(2)-10(3) copies/rat SON pair. However, the estimated copy number of the intron 2-containing OT hnRNA is much larger, approximately 10(6) copies/SON pair. The relative distributions of all the OT and VP RNA species were invariant and independent of the physiological status of the rats (e.g., osmotically stimulated or lactating rats). Using intron-specific riboprobes against hnRNAs, we demonstrate by fluorescence in situ hybridization strong signals of OT hnRNA containing intron 2 predominantly in the cytoplasm, in contrast to the localization of the VP hnRNA found only in the nuclei. Taken together, these data support the view that the splicing patterns between OT and VP gene transcripts are different and show that there is a selective cytoplasmic retention of OT intron 2.
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Affiliation(s)
- Chunmei Yue
- Molecular Neuroscience Section, Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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Gene expression profiling of human epidermal keratinocytes in simulated microgravity and recovery cultures. GENOMICS PROTEOMICS & BIOINFORMATICS 2008; 6:8-28. [PMID: 18558382 PMCID: PMC5054098 DOI: 10.1016/s1672-0229(08)60017-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Simulated microgravity (SMG) bioreactors and DNA microarray technology are powerful tools to identify “space genes” that play key roles in cellular response to microgravity. We applied these biotechnology tools to investigate SMG and post-SMG recovery effects on human epidermal keratinocytes by exposing cells to SMG for 3, 4, 9, and 10 d using the high aspect ratio vessel bioreactor followed by recovery culturing for 15, 50, and 60 d in normal gravity. As a result, we identified 162 differentially expressed genes, 32 of which were “center genes” that were most consistently affected in the time course experiments. Eleven of the center genes were from the integrated stress response pathways and were coordinately down-regulated. Another seven of the center genes, which are all metallothionein MT-I and MT-II isoforms, were coordinately up-regulated. In addition, HLA-G, a key gene in cellular immune response suppression, was found to be significantly up-regulated during the recovery phase. Overall, more than 80% of the differentially expressed genes from the shorter exposures (≤4 d) recovered in 15 d; for longer (≥9 d) exposures, more than 50 d were needed to recover to the impact level of shorter exposures. The data indicated that shorter SMG exposure duration would lead to quicker and more complete recovery from the microgravity effect.
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Abstract
Utilization of gene silencing effectors, such as microRNA (miRNA) and small hairpin RNA (shRNA), provides a powerful new strategy for human skin care in vivo, particularly for hyperpigmentation treatment and aging prevention. In this study, tyrosinase (Tyr), the rate-limiting enzyme of melanin (black pigment) biosynthesis, was served as a target for treatment of hyperpigmentation in mouse and human skins. There are over 54 native microRNA capable of silencing human tyrosinase for skin whitening and lightening. To this, we have designed a mir-434-5p homologue and used it to successfully demonstrate the feasibility of miRNA-mediated skin whitening and lightening in vitro and in vivo. Under the same experimental condition in the trials, Pol-II-directed intronic mir-434-5p expression did not cause any detectable sign of cytotoxicity, whereas siRNAs targeting the same sequence often induced certain nonspecific mRNA degradation as previously reported. Because the intronic miRNA-mediated gene silencing pathway is tightly regulated by multiple intracellular surveillance systems, including Pol-II transcription, RNA splicing, exosomal digestion and nonsense-mediated RNA decay (NMD), the current findings underscore the fact that intronic miRNA agents, such as manually re-designed mir-434-5p homologues, are effective, target-specific and safe to be used for skin whitening without any detectable cytotoxic effect. Given that the human skins also express a variety of other native miRNAs, we may re-design these miRNAs based on their individual functions for skin care, which may provide significant insights into areas of opportunity for new cosmetic and/or therapeutical applications.
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Affiliation(s)
- David Ts Wu
- Institute of Mello Biotechnology, Taipei, Taiwan, ROC
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50
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Köhler CU, Roos PH. Focus on the intermediate state: immature mRNA of cytochromes P450--methods and insights. Anal Bioanal Chem 2008; 392:1109-22. [PMID: 18762920 DOI: 10.1007/s00216-008-2352-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 08/11/2008] [Accepted: 08/14/2008] [Indexed: 01/28/2023]
Abstract
The scattered and limited data on hnRNAs (pre-mRNAs) of cytochromes P450 (CYP) are compiled and discussed for the first time. The methods for determination and quantification of hnRNAs are compared. In most cases, CYP hnRNA levels were determined as a parameter of transcriptional activity. It is known, however, that some CYPs, in particular CYP2E1, are in addition specifically and extensively regulated by post-transcriptional processes. Obviously, these processes also influence the processing of CYP hnRNAs so that their levels cannot be considered a mere result of transcription. The underlying mechanisms of post-transcriptional CYP hnRNA and mRNA regulation are not well understood. It is our aim therefore to bring together available data on CYP hnRNA and to discuss them in the light of recent advances in knowledge concerning pre-mRNA processing and interactions between RNA and low molecular weight interfering RNAs. By doing this, we hope to drive research in a direction which appears promising in providing some long-awaited answers with respect to mechanisms of post-transcriptional CYP regulation.
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Affiliation(s)
- Christina U Köhler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystr. 67, 44139, Dortmund, Germany
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