1
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Brownmiller T, Caplen NJ. The HNRNPF/H RNA binding proteins and disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1788. [PMID: 37042074 PMCID: PMC10523889 DOI: 10.1002/wrna.1788] [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: 10/31/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 04/13/2023]
Abstract
The members of the HNRNPF/H family of heterogeneous nuclear RNA proteins-HNRNPF, HNRNPH1, HNRNPH2, HNRNPH3, and GRSF1, are critical regulators of RNA maturation. Documented functions of these proteins include regulating splicing, particularly alternative splicing, 5' capping and 3' polyadenylation of RNAs, and RNA export. The assignment of these proteins to the HNRNPF/H protein family members relates to differences in the amino acid composition of their RNA recognition motifs, which differ from those of other RNA binding proteins (RBPs). HNRNPF/H proteins typically bind RNA sequences enriched with guanine (G) residues, including sequences that, in the presence of a cation, have the potential to form higher-order G-quadruplex structures. The need to further investigate members of the HNRNPF/H family of RBPs has intensified with the recent descriptions of their involvement in several disease states, including the pediatric tumor Ewing sarcoma and the hematological malignancy mantle cell lymphoma; newly described groups of developmental syndromes; and neuronal-related disorders, including addictive behavior. Here, to foster the study of the HNRNPF/H family of RBPs, we discuss features of the genes encoding these proteins, their structures and functions, and emerging contributions to disease. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Tayvia Brownmiller
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland, USA
| | - Natasha J Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland, USA
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2
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Barreira M, Kerridge C, Jorda S, Olofsson D, Neumann A, Horton H, Smith-Moore S. Enzymatically amplified linear dbDNA TM as a rapid and scalable solution to industrial lentiviral vector manufacturing. Gene Ther 2023; 30:122-131. [PMID: 35606492 PMCID: PMC9935383 DOI: 10.1038/s41434-022-00343-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/09/2022]
Abstract
Traditional bacterial fermentation techniques used to manufacture plasmid are time-consuming, expensive, and inherently unstable. The production of sufficient GMP grade material thus imposes a major bottleneck on industrial-scale manufacturing of lentiviral vectors (LVV). Touchlight's linear doggybone DNA (dbDNATM) is an enzymatically amplified DNA vector produced with exceptional speed through an in vitro dual enzyme process, enabling industrial-scale manufacturing of GMP material in a fraction of the time required for plasmid. We have previously shown that dbDNATM can be used to produce functional LVV; however, obtaining high LVV titres remained a challenge. Here, we aimed to demonstrate that dbDNATM could be optimised for the manufacture of high titre LVV. We found that dbDNATM displayed a unique transfection and expression profile in the context of LVV production, which necessitated the optimisation of DNA input and construct ratios. Furthermore, we demonstrate that efficient 3' end processing of viral genomic RNA (vgRNA) derived from linear dbDNATM transfer vectors required the addition of a strong 3' termination signal and downstream spacer sequence to enable efficient vgRNA packaging. Using these improved vector architectures along with optimised transfection conditions, we were able to produce a CAR19h28z LVV with equivalent infectious titres as achieved using plasmid, demonstrating that dbDNATM technology can provide a highly effective solution to the plasmid bottleneck.
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Affiliation(s)
- Maria Barreira
- Touchlight Genetics Ltd, Hampton, TW12 2ER, United Kingdom.,Cell and Gene Therapy Catapult, Guy's Hospital, London, SE1 9RT, United Kingdom
| | | | - Sara Jorda
- Touchlight Genetics Ltd, Hampton, TW12 2ER, United Kingdom.,Medical Research Institute La Fe, 46026, Valencia, Spain
| | - Didrik Olofsson
- Omiqa Bioinformatics GmbH, Altensteinstraße 40, 14195, Berlin, Germany
| | - Alexander Neumann
- Omiqa Bioinformatics GmbH, Altensteinstraße 40, 14195, Berlin, Germany
| | - Helen Horton
- Touchlight Genetics Ltd, Hampton, TW12 2ER, United Kingdom
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3
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Vannutelli A, Perreault JP, Ouangraoua A. G-quadruplex occurrence and conservation: more than just a question of guanine–cytosine content. NAR Genom Bioinform 2022; 4:lqac010. [PMID: 35261973 PMCID: PMC8896161 DOI: 10.1093/nargab/lqac010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 12/06/2021] [Accepted: 02/25/2022] [Indexed: 12/14/2022] Open
Abstract
G-quadruplexes are motifs found in DNA and RNA that can fold into tertiary structures. Until now, they have been studied experimentally mainly in humans and a few other species. Recently, predictions have been made with bacterial and archaeal genomes. Nevertheless, a global comparison of predicted G4s (pG4s) across and within the three living kingdoms has not been addressed. In this study, we aimed to predict G4s in genes and transcripts of all kingdoms of living organisms and investigated the differences in their distributions. The relation of the predictions with GC content was studied. It appears that GC content is not the only parameter impacting G4 predictions and abundance. The distribution of pG4 densities varies depending on the class of transcripts and the group of species. Indeed, we have observed that, in coding transcripts, there are more predicted G4s than expected for eukaryotes but not for archaea and bacteria, while in noncoding transcripts, there are as many or fewer predicted G4s in all species groups. We even noticed that some species with the same GC content presented different pG4 profiles. For instance, Leishmania major and Chlamydomonas reinhardtii both have 60% of GC content, but the former has a pG4 density of 0.07 and the latter 1.16.
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Affiliation(s)
- Anaïs Vannutelli
- Department of Computer Science, Faculté des sciences, Université de Sherbrooke, QC, J1K 2R1, Canada
- Department of Biochemistry and Functional Genomics, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, QC J1E 4K8, Canada
| | - Jean-Pierre Perreault
- Department of Computer Science, Faculté des sciences, Université de Sherbrooke, QC, J1K 2R1, Canada
| | - Aïda Ouangraoua
- Department of Computer Science, Faculté des sciences, Université de Sherbrooke, QC, J1K 2R1, Canada
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4
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Simko EAJ, Liu H, Zhang T, Velasquez A, Teli S, Haeusler AR, Wang J. G-quadruplexes offer a conserved structural motif for NONO recruitment to NEAT1 architectural lncRNA. Nucleic Acids Res 2020; 48:7421-7438. [PMID: 32496517 PMCID: PMC7367201 DOI: 10.1093/nar/gkaa475] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 06/02/2020] [Indexed: 12/11/2022] Open
Abstract
The long non-coding RNA NEAT1 serves as a scaffold for the assembly of paraspeckles, membraneless nuclear organelles involved in gene regulation. Paraspeckle assembly requires NEAT1 recruitment of the RNA-binding protein NONO, however the NEAT1 elements responsible for recruitment are unknown. Herein we present evidence that previously unrecognized structural features of NEAT1 serve an important role in these interactions. Led by the initial observation that NONO preferentially binds the G-quadruplex conformation of G-rich C9orf72 repeat RNA, we find that G-quadruplex motifs are abundant and conserved features of NEAT1. Furthermore, we determine that NONO binds NEAT1 G-quadruplexes with structural specificity and provide evidence that G-quadruplex motifs mediate NONO-NEAT1 association, with NONO binding sites on NEAT1 corresponding largely to G-quadruplex motifs, and treatment with a G-quadruplex-disrupting small molecule causing dissociation of native NONO-NEAT1 complexes. Together, these findings position G-quadruplexes as a primary candidate for the NONO-recruiting elements of NEAT1 and provide a framework for further investigation into the role of G-quadruplexes in paraspeckle formation and function.
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Affiliation(s)
- Eric A J Simko
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Honghe Liu
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tao Zhang
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Adan Velasquez
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shraddha Teli
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Aaron R Haeusler
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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5
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Nourse J, Spada S, Danckwardt S. Emerging Roles of RNA 3'-end Cleavage and Polyadenylation in Pathogenesis, Diagnosis and Therapy of Human Disorders. Biomolecules 2020; 10:biom10060915. [PMID: 32560344 PMCID: PMC7356254 DOI: 10.3390/biom10060915] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/10/2020] [Accepted: 06/13/2020] [Indexed: 12/11/2022] Open
Abstract
A crucial feature of gene expression involves RNA processing to produce 3′ ends through a process termed 3′ end cleavage and polyadenylation (CPA). This ensures the nascent RNA molecule can exit the nucleus and be translated to ultimately give rise to a protein which can execute a function. Further, alternative polyadenylation (APA) can produce distinct transcript isoforms, profoundly expanding the complexity of the transcriptome. CPA is carried out by multi-component protein complexes interacting with multiple RNA motifs and is tightly coupled to transcription, other steps of RNA processing, and even epigenetic modifications. CPA and APA contribute to the maintenance of a multitude of diverse physiological processes. It is therefore not surprising that disruptions of CPA and APA can lead to devastating disorders. Here, we review potential CPA and APA mechanisms involving both loss and gain of function that can have tremendous impacts on health and disease. Ultimately we highlight the emerging diagnostic and therapeutic potential CPA and APA offer.
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Affiliation(s)
- Jamie Nourse
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany; (J.N.); (S.S.)
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
| | - Stefano Spada
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany; (J.N.); (S.S.)
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
| | - Sven Danckwardt
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany; (J.N.); (S.S.)
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Rhine-Main, Germany
- Correspondence:
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6
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Vainberg Slutskin I, Weinberger A, Segal E. Sequence determinants of polyadenylation-mediated regulation. Genome Res 2019; 29:1635-1647. [PMID: 31530582 PMCID: PMC6771402 DOI: 10.1101/gr.247312.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 08/13/2019] [Indexed: 12/31/2022]
Abstract
The cleavage and polyadenylation reaction is a crucial step in transcription termination and pre-mRNA maturation in human cells. Despite extensive research, the encoding of polyadenylation-mediated regulation of gene expression within the DNA sequence is not well understood. Here, we utilized a massively parallel reporter assay to inspect the effect of over 12,000 rationally designed polyadenylation sequences (PASs) on reporter gene expression and cleavage efficiency. We find that the PAS sequence can modulate gene expression by over five orders of magnitude. By using a uniquely designed scanning mutagenesis data set, we gain mechanistic insight into various modes of action by which the cleavage efficiency affects the sensitivity or robustness of the PAS to mutation. Furthermore, we employ motif discovery to identify both known and novel sequence motifs associated with PAS-mediated regulation. By leveraging the large scale of our data, we train a deep learning model for the highly accurate prediction of RNA levels from DNA sequence alone (R = 0.83). Moreover, we devise unique approaches for predicting exact cleavage sites for our reporter constructs and for endogenous transcripts. Taken together, our results expand our understanding of PAS-mediated regulation, and provide an unprecedented resource for analyzing and predicting PAS for regulatory genomics applications.
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Affiliation(s)
- Ilya Vainberg Slutskin
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 7610001, Israel.,Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Adina Weinberger
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 7610001, Israel.,Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eran Segal
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 7610001, Israel.,Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
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7
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Kharel P, Balaratnam S, Beals N, Basu S. The role of RNA G-quadruplexes in human diseases and therapeutic strategies. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1568. [PMID: 31514263 DOI: 10.1002/wrna.1568] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 08/09/2019] [Accepted: 08/27/2019] [Indexed: 12/13/2022]
Abstract
G-quadruplexes (GQs) are four-stranded secondary structures formed by G-rich nucleic acid sequence(s). DNA GQs are present abundantly in the genome and affect a wide range of processes associated with DNA. Recent studies show that RNA GQs are present in different transcripts, including coding and noncoding areas of mRNA, telomeric RNA as well as in other premature and mature noncoding RNAs. When present at specific locations within the RNAs, GQs play important roles in key biological functions, including the regulation of gene expression and telomere homeostasis. RNA GQs regulate pre-mRNA processing, such as splicing and polyadenylation. Evidently, among other processes, RNA GQs also control mRNA translation, miRNA and piRNA biogenesis, and RNA localization. The regulatory mechanisms controlled by RNA GQs mainly involve binding to RNA binding protein that modulate GQ conformation or serve as an entity in recruiting additional protein regulators to act as a block element to the processing machinery. Here we provide an overview of the ever-increasing number of discoveries revealing the role of RNA GQs in biology and their relevance in human diseases and therapeutics. This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Prakash Kharel
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio.,Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Sumirtha Balaratnam
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio.,Chemical Biology Laboratory, National Cancer Institute, Frederick, Maryland
| | - Nathan Beals
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York
| | - Soumitra Basu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio
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8
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Hagen T, Malinowska AL, Lightfoot HL, Bigatti M, Hall J. Site-Specific Fluorophore Labeling of Guanosines in RNA G-Quadruplexes. ACS OMEGA 2019; 4:8472-8479. [PMID: 31459936 PMCID: PMC6648711 DOI: 10.1021/acsomega.9b00704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/24/2019] [Indexed: 05/08/2023]
Abstract
RNA G-quadruplexes are RNA secondary structures that are implicated in many cellular processes. Although conventional biophysical techniques are widely used for their in vitro characterization, more advanced methods are needed to study complex equilibria and the kinetics of their folding. We have developed a new Förster resonance energy-transfer-based method to detect the folding of RNA G-quadruplexes, which is enabled by labeling the 2'-positions of participating guanosines with fluorophores. Importantly, this does not interfere with the required anti conformation of the nucleobase in a quadruplex with parallel topology. Sequential click reactions on the solid phase and in solution using a stop-and-go strategy circumvented the issue of unselective cross-labeling. We exemplified the method on a series of sequences under different assay conditions. In contrast to the commonly used end-labeling approach, our internal labeling strategy would also allow the study of G-quadruplex formation in long functional RNAs.
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9
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Schäfer P, Tüting C, Schönemann L, Kühn U, Treiber T, Treiber N, Ihling C, Graber A, Keller W, Meister G, Sinz A, Wahle E. Reconstitution of mammalian cleavage factor II involved in 3' processing of mRNA precursors. RNA (NEW YORK, N.Y.) 2018; 24:1721-1737. [PMID: 30139799 PMCID: PMC6239180 DOI: 10.1261/rna.068056.118] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/17/2018] [Indexed: 05/05/2023]
Abstract
Cleavage factor II (CF II) is a poorly characterized component of the multiprotein complex catalyzing 3' cleavage and polyadenylation of mammalian mRNA precursors. We have reconstituted CF II as a heterodimer of hPcf11 and hClp1. The heterodimer is active in partially reconstituted cleavage reactions, whereas hClp1 by itself is not. Pcf11 moderately stimulates the RNA 5' kinase activity of hClp1; the kinase activity is dispensable for RNA cleavage. CF II binds RNA with nanomolar affinity. Binding is mediated mostly by the two zinc fingers in the C-terminal region of hPcf11. RNA is bound without pronounced sequence-specificity, but extended G-rich sequences appear to be preferred. We discuss the possibility that CF II contributes to the recognition of cleavage/polyadenylation substrates through interaction with G-rich far-downstream sequence elements.
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Affiliation(s)
- Peter Schäfer
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Christian Tüting
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Lars Schönemann
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Uwe Kühn
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Thomas Treiber
- Biochemistry Center Regensburg, Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Nora Treiber
- Biochemistry Center Regensburg, Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Christian Ihling
- Institute of Pharmacy, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Anne Graber
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - Walter Keller
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - Gunter Meister
- Biochemistry Center Regensburg, Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Andrea Sinz
- Institute of Pharmacy, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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10
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Deng Z, Zhang S, Gu S, Ni X, Zeng W, Li X. Useful Bicistronic Reporter System for Studying Poly(A) Site-Defining cis Elements and Regulation of Alternative Polyadenylation. Int J Mol Sci 2018; 19:E279. [PMID: 29342112 PMCID: PMC5796225 DOI: 10.3390/ijms19010279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/05/2018] [Accepted: 01/15/2018] [Indexed: 12/15/2022] Open
Abstract
The link between polyadenylation (pA) and various biological, behavioral, and pathological events of eukaryotes underlines the need to develop in vivo polyadenylation assay methods for characterization of the cis-acting elements, trans-acting factors and environmental stimuli that affect polyadenylation efficiency and/or relative usage of two alternative polyadenylation (APA) sites. The current protein-based CAT or luciferase reporter systems can measure the polyadenylation efficiency of a single pA site or candidate cis element but not the choice of two APA sites. To address this issue, we developed a set of four new bicistronic reporter vectors that harbor either two luciferase or fluorescence protein open reading frames connected with one Internal Ribosome Entry Site (IRES). Transfection of single or dual insertion constructs of these vectors into mammalian cells demonstrated that they could be utilized not only to quantify the strength of a single candidate pA site or cis element, but also to accurately measure the relative usage of two APA sites at both the mRNA (qRT-PCR) and protein levels. This represents the first reporter system that can study polyadenylation efficiency of a single pA site or element and regulation of two APA sites at both the mRNA and protein levels.
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Affiliation(s)
- Zhongyuan Deng
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling 712100, Shaanxi, China.
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Shen Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Shaohua Gu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Xinzhi Ni
- United States Department of Agriculture, Agricultural Research Service, Crop Genetics and Breeding Research Unit, Tifton, GA 31793, USA.
| | - Wenxian Zeng
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling 712100, Shaanxi, China.
| | - Xianchun Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
- Department of Entomology and BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA.
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11
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Fay MM, Lyons SM, Ivanov P. RNA G-Quadruplexes in Biology: Principles and Molecular Mechanisms. J Mol Biol 2017; 429:2127-2147. [PMID: 28554731 PMCID: PMC5603239 DOI: 10.1016/j.jmb.2017.05.017] [Citation(s) in RCA: 271] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 11/26/2022]
Abstract
G-quadruplexes (G4s) are extremely stable DNA or RNA secondary structures formed by sequences rich in guanine. These structures are implicated in many essential cellular processes, and the number of biological functions attributed to them continues to grow. While DNA G4s are well understood on structural and, to some extent, functional levels, RNA G4s and their functions have received less attention. The presence of bona fide RNA G4s in cells has long been a matter of debate. The development of G4-specific antibodies and ligands hinted on their presence in vivo, but recent advances in RNA sequencing coupled with chemical footprinting suggested the opposite. In this review, we will critically discuss the biology of RNA G4s focusing on the molecular mechanisms underlying their proposed functions.
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Affiliation(s)
- Marta M Fay
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Shawn M Lyons
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; The Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
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12
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Laishram RS. Poly(A) polymerase (PAP) diversity in gene expression--star-PAP vs canonical PAP. FEBS Lett 2014; 588:2185-97. [PMID: 24873880 PMCID: PMC6309179 DOI: 10.1016/j.febslet.2014.05.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/02/2014] [Accepted: 05/15/2014] [Indexed: 01/09/2023]
Abstract
Almost all eukaryotic mRNAs acquire a poly(A) tail at the 3'-end by a concerted RNA processing event: cleavage and polyadenylation. The canonical PAP, PAPα, was considered the only nuclear PAP involved in general polyadenylation of mRNAs. A phosphoinositide-modulated nuclear PAP, Star-PAP, was then reported to regulate a select set of mRNAs in the cell. In addition, several non-canonical PAPs have been identified with diverse cellular functions. Further, canonical PAP itself exists in multiple isoforms thus illustrating the diversity of PAPs. In this review, we compare two nuclear PAPs, Star-PAP and PAPα with a general overview of PAP diversity in the cell. Emerging evidence suggests distinct niches of target pre-mRNAs for the two PAPs and that modulation of these PAPs regulates distinct cellular functions.
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Affiliation(s)
- Rakesh S Laishram
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India.
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13
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Frees S, Menendez C, Crum M, Bagga PS. QGRS-Conserve: a computational method for discovering evolutionarily conserved G-quadruplex motifs. Hum Genomics 2014; 8:8. [PMID: 24885782 PMCID: PMC4017754 DOI: 10.1186/1479-7364-8-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 04/21/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Nucleic acids containing guanine tracts can form quadruplex structures via non-Watson-Crick base pairing. Formation of G-quadruplexes is associated with the regulation of important biological functions such as transcription, genetic instability, DNA repair, DNA replication, epigenetic mechanisms, regulation of translation, and alternative splicing. G-quadruplexes play important roles in human diseases and are being considered as targets for a variety of therapies. Identification of functional G-quadruplexes and the study of their overall distribution in genomes and transcriptomes is an important pursuit. Traditional computational methods map sequence motifs capable of forming G-quadruplexes but have difficulty in distinguishing motifs that occur by chance from ones which fold into G-quadruplexes. RESULTS We present Quadruplex forming 'G'-rich sequences (QGRS)-Conserve, a computational method for calculating motif conservation across exomes and supports filtering to provide researchers with more precise methods of studying G-quadruplex distribution patterns. Our method quantitatively evaluates conservation between quadruplexes found in homologous nucleotide sequences based on several motif structural characteristics. QGRS-Conserve also efficiently manages overlapping G-quadruplex sequences such that the resulting datasets can be analyzed effectively. CONCLUSIONS We have applied QGRS-Conserve to identify a large number of G-quadruplex motifs in the human exome conserved across several mammalian and non-mammalian species. We have successfully identified multiple homologs of many previously published G-quadruplexes that play post-transcriptional regulatory roles in human genes. Preliminary large-scale analysis identified many homologous G-quadruplexes in the 5'- and 3'-untranslated regions of mammalian species. An expectedly smaller set of G-quadruplex motifs was found to be conserved across larger phylogenetic distances. QGRS-Conserve provides means to build datasets that can be filtered and categorized in a variety of biological dimensions for more targeted studies in order to better understand the roles that G-quadruplexes play.
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Affiliation(s)
- Scott Frees
- Department of Computer Science, Ramapo College of New Jersey, 505 Ramapo Valley Road, Mahwah, NJ 08807, USA
| | - Camille Menendez
- Department of Bioinformatics, Ramapo College of New Jersey, 505 Ramapo Valley Road, Mahwah, NJ 08807, USA
| | - Matt Crum
- Department of Bioinformatics, Ramapo College of New Jersey, 505 Ramapo Valley Road, Mahwah, NJ 08807, USA
| | - Paramjeet S Bagga
- Department of Bioinformatics, Ramapo College of New Jersey, 505 Ramapo Valley Road, Mahwah, NJ 08807, USA
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Majerciak V, Ni T, Yang W, Meng B, Zhu J, Zheng ZM. A viral genome landscape of RNA polyadenylation from KSHV latent to lytic infection. PLoS Pathog 2013; 9:e1003749. [PMID: 24244170 PMCID: PMC3828183 DOI: 10.1371/journal.ppat.1003749] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/20/2013] [Indexed: 11/30/2022] Open
Abstract
RNA polyadenylation (pA) is one of the major steps in regulation of gene expression at the posttranscriptional level. In this report, a genome landscape of pA sites of viral transcripts in B lymphocytes with Kaposi sarcoma-associated herpesvirus (KSHV) infection was constructed using a modified PA-seq strategy. We identified 67 unique pA sites, of which 55 could be assigned for expression of annotated ∼90 KSHV genes. Among the assigned pA sites, twenty are for expression of individual single genes and the rest for multiple genes (average 2.7 genes per pA site) in cluster-gene loci of the genome. A few novel viral pA sites that could not be assigned to any known KSHV genes are often positioned in the antisense strand to ORF8, ORF21, ORF34, K8 and ORF50, and their associated antisense mRNAs to ORF21, ORF34 and K8 could be verified by 3′RACE. The usage of each mapped pA site correlates to its peak size, the larger (broad and wide) peak size, the more usage and thus, the higher expression of the pA site-associated gene(s). Similar to mammalian transcripts, KSHV RNA polyadenylation employs two major poly(A) signals, AAUAAA and AUUAAA, and is regulated by conservation of cis-elements flanking the mapped pA sites. Moreover, we found two or more alternative pA sites downstream of ORF54, K2 (vIL6), K9 (vIRF1), K10.5 (vIRF3), K11 (vIRF2), K12 (Kaposin A), T1.5, and PAN genes and experimentally validated the alternative polyadenylation for the expression of KSHV ORF54, K11, and T1.5 transcripts. Together, our data provide not only a comprehensive pA site landscape for understanding KSHV genome structure and gene expression, but also the first evidence of alternative polyadenylation as another layer of posttranscriptional regulation in viral gene expression. A genome-wide polyadenylation landscape in the expression of human herpesviruses has not been reported. In this study, we provide the first genome landscape of viral RNA polyadenylation sites in B cells from KSHV latent to lytic infection by using a modified PA-seq protocol and selectively validated by 3′ RACE. We found that KSHV genome contains 67 active pA sites for the expression of its ∼90 genes and a few antisense transcripts. Among the mapped pA sites, a large fraction of them are for the expression of cluster genes and the production of bicistronic or polycistronic transcripts from KSHV genome and only one-third are used for the expression of single genes. We found that the size of individual PA peaks is positively correlated with the usage of corresponding pA site, which is determined by the number of reads within the PA peak from latent to lytic KSHV infection, and the strength of cis-elements surrounding KSHV pA site determines the expression level of viral genes. Lastly, we identified and experimentally validated alternative polyadenylation of KSHV ORF54, T1.5, and K11 during viral lytic infection. To our knowledge, this is the first report on alternative polyadenylation events in KSHV infection.
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Affiliation(s)
- Vladimir Majerciak
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ting Ni
- DNA Sequencing and Genomics Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Wenjing Yang
- DNA Sequencing and Genomics Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bowen Meng
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jun Zhu
- DNA Sequencing and Genomics Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JZ); (ZMZ)
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JZ); (ZMZ)
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15
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Curtis EA, Liu DR. Discovery of widespread GTP-binding motifs in genomic DNA and RNA. ACTA ACUST UNITED AC 2013; 20:521-32. [PMID: 23601641 DOI: 10.1016/j.chembiol.2013.02.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 01/22/2013] [Accepted: 02/25/2013] [Indexed: 12/20/2022]
Abstract
Biological RNAs that bind small molecules have been implicated in a variety of regulatory and catalytic processes. Inspired by these examples, we used in vitro selection to search a pool of genome-encoded RNA fragments for naturally occurring GTP aptamers. Several aptamer classes were identified, including one (the "G motif") with a G-quadruplex structure. Further analysis revealed that most RNA and DNA G-quadruplexes bind GTP. The G motif is abundant in eukaryotes, and the human genome contains ~75,000 examples with dissociation constants comparable to the GTP concentration of a eukaryotic cell (~300 μM). G-quadruplexes play roles in diverse cellular processes, and our findings raise the possibility that GTP may play a role in the function of these elements. Consistent with this possibility, the sequence requirements of several classes of regulatory G-quadruplexes parallel those of GTP binding.
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Affiliation(s)
- Edward A Curtis
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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16
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Bagga JS, D’Antonio LA. Role of conserved cis-regulatory elements in the post-transcriptional regulation of the human MECP2 gene involved in autism. Hum Genomics 2013; 7:19. [PMID: 24040966 PMCID: PMC3844687 DOI: 10.1186/1479-7364-7-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/04/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The MECP2 gene codes for methyl CpG binding protein 2 which regulates activities of other genes in the early development of the brain. Mutations in this gene have been associated with Rett syndrome, a form of autism. The purpose of this study was to investigate the role of evolutionarily conserved cis-elements in regulating the post-transcriptional expression of the MECP2 gene and to explore their possible correlations with a mutation that is known to cause mental retardation. RESULTS A bioinformatics approach was used to map evolutionarily conserved cis-regulatory elements in the transcribed regions of the human MECP2 gene and its mammalian orthologs. Cis-regulatory motifs including G-quadruplexes, microRNA target sites, and AU-rich elements have gained significant importance because of their role in key biological processes and as therapeutic targets. We discovered in the 5'-UTR (untranslated region) of MECP2 mRNA a highly conserved G-quadruplex which overlapped a known deletion in Rett syndrome patients with decreased levels of MeCP2 protein. We believe that this 5'-UTR G-quadruplex could be involved in regulating MECP2 translation. We mapped additional evolutionarily conserved G-quadruplexes, microRNA target sites, and AU-rich elements in the key sections of both untranslated regions. Our studies suggest the regulation of translation, mRNA turnover, and development-related alternative MECP2 polyadenylation, putatively involving interactions of conserved cis-regulatory elements with their respective trans factors and complex interactions among the trans factors themselves. We discovered highly conserved G-quadruplex motifs that were more prevalent near alternative splice sites as compared to the constitutive sites of the MECP2 gene. We also identified a pair of overlapping G-quadruplexes at an alternative 5' splice site that could potentially regulate alternative splicing in a negative as well as a positive way in the MECP2 pre-mRNAs. CONCLUSIONS A Rett syndrome mutation with decreased protein expression was found to be associated with a conserved G-quadruplex. Our studies suggest that MECP2 post-transcriptional gene expression could be regulated by several evolutionarily conserved cis-elements like G-quadruplex motifs, microRNA target sites, and AU-rich elements. This phylogenetic analysis has provided some interesting and valuable insights into the regulation of the MECP2 gene involved in autism.
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Affiliation(s)
- Joetsaroop S Bagga
- John P. Stevens High School, 855 Grove Ave., Edison, NJ 08820, USA
- Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213, USA
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17
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RRP1B is a metastasis modifier that regulates the expression of alternative mRNA isoforms through interactions with SRSF1. Oncogene 2013; 33:1818-27. [PMID: 23604122 PMCID: PMC3925194 DOI: 10.1038/onc.2013.133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 02/14/2013] [Accepted: 02/28/2013] [Indexed: 12/22/2022]
Abstract
RRP1B (ribosomal RNA processing 1 homolog B) was first identified as a metastasis susceptibility gene in breast cancer through its ability to modulate gene expression in a manner that can be used to accurately predict prognosis in breast cancer. However, the mechanism(s) by which RRP1B modulates gene expression is currently unclear. Many RRP1B binding candidates are involved in alternative splicing, a mechanism of gene expression regulation that is increasingly recognized to be involved in cancer progression and metastasis. One such target is SRSF1 (SF2/ASF), an essential splicing regulator that also functions as an oncoprotein. Earlier studies demonstrated that splicing and transcription occur concurrently and are coupled processes. Given that RRP1B regulates transcriptional activity, we hypothesized that RRP1B also regulates the expression of alternative mRNA isoforms through its interaction with SRSF1. Interaction between RRP1B and SRSF1 was verified by co-immunoprecipitation and co-immunofluorescence. Treatment of cells with transcriptional inhibitors significantly increased this interaction, demonstrating that the association of these two proteins is transcriptionally regulated. To assess the role of RRP1B in the regulation of alternative isoform expression, RNA-seq data were generated from control and Rrp1b-knockdown cells. Knockdown of Rrp1b induced a significant change in isoform expression in over 600 genes compared to control cell lines. This was verified by qRT-PCR using isoform-specific primers. Pathway enrichment analyses identified cell cycle and checkpoint regulation to be those most affected by Rrp1b knockdown. These data suggest that RRP1B suppresses metastatic progression by altering the transcriptome through its interaction with splicing regulators such as SRSF1.
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18
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Darmon SK, Lutz CS. Novel upstream and downstream sequence elements contribute to polyadenylation efficiency. RNA Biol 2012; 9:1255-65. [PMID: 23085579 DOI: 10.4161/rna.21957] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polyadenylation is a 3' mRNA processing event that contributes to gene expression by affecting stability, export and translation of mRNA. Human polyadenylation signals (PAS) have core and auxiliary elements that bind polyadenylation factors upstream and downstream of the cleavage site. The majority of mRNAs do not have optimal upstream and downstream core elements and therefore auxiliary elements can aid in polyadenylation efficiency. Auxiliary elements have previously been identified and studied in a small number of mRNAs. We previously used a global approach to examine auxiliary elements to identify overrepresented motifs by a bioinformatic survey. This predicted information was used to direct our in vivo validation studies, all of which were accomplished using both a tandem in vivo polyadenylation assay and using reporter protein assays measured as luciferase activity. Novel auxiliary elements were placed in a test polyadenylation signal. An in vivo polyadenylation assay was used to determine the strength of the polyadenylation signal. All but one of the novel auxiliary elements enhanced the test polyadenylation signal. Effects of these novel auxiliary elements were also measured by a luciferase assay when placed in the 3' UTR of a firefly luciferase reporter. Two novel downstream auxiliary elements and all of the novel upstream auxiliary elements showed an increase in reporter protein levels. Many well known auxiliary polyadenylation elements have been found to occur in multiple sets. However, in our study, multiple copies of novel auxiliary elements brought reporter protein levels as well as polyadenylation choice back to wild type levels. Structural features of these novel auxiliary elements may also affect the role of auxiliary elements. A MS2 structure placed upstream of the polyadenylation signal can affect polyadenylation in both the positive and negative direction. A large change in RNA structure by using novel complementary auxiliary element also decreased polyadenylation choice and reporter protein levels. Therefore, we conclude that RNA structure has an important role in polyadenylation efficiency.
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Affiliation(s)
- Sarah K Darmon
- Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, and the Graduate School of Biomedical Sciences, Newark, NJ, USA
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19
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Zarudnaya MI, Potyahaylo AL, Kolomiets IM, Hovorun DМ. Structural model of the complete poly(A) region of HIV-1 pre-mRNA. J Biomol Struct Dyn 2012; 31:1044-56. [PMID: 22963228 DOI: 10.1080/07391102.2012.718530] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In the HIV-1 retrovirus, identical sequences encompassing the AAUAAA hexamer and the U/GU-rich downstream sequence element (DSE) that compose the core poly(A) site are present at both the 5' and 3' ends of the HIV-1 pre-mRNA. The AAUAAA hexamer is partly occluded by base pairing in the upper part of a semi-stable polyA hairpin. This sets the stage for regulation of HIV-1 polyadenylation, which involves reaction suppression at the 5' end and its stimulation at the 3' end. Efficient utilization of the 3' core poly(A) site is promoted by major and minor upstream sequence elements (USEs) which are uniquely present at the 3' end of the HIV-1 transcript. The structures of the HIV-1 5' and 3' poly(A) sites are defined by overall architecture of complete 5' and 3' untranslated terminal regions (UTRs). To our knowledge, there is still no structural model of a complete 3' UTR of the HIV-1 pre-mRNA and complete 3' poly(A) region including the USEs except the fact that the polyA and transactivation response (TAR) hairpins are present at both ends of the HIV-1 pre-mRNA. In this work, we predicted a secondary structure of the 3' UTR of HIV-1 pre-mRNA based on our observation that the minor USEs are located in a region with a high potential to form G-quadruplex structures. We first present structural models for the major USE, complete 3' poly(A) region, and almost entire 3' UTR of HIV-1 pre-mRNA. Our models are built based on the mfold and UNAFold secondary structure prediction of these regions for about 1500 HIV-1 isolates of different subtypes and recombinant forms. We have demonstrated that these models are valid for most of the HIV-1 isolates studied. The proposed models include the known TAR and polyA hairpins and new structural elements containing the U-rich tract of the major USE and U/GU-rich DSE which are fully exposed and accessible to the polyadenylation machinery, which confirms the functional competence of our models.
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Affiliation(s)
- Margarita I Zarudnaya
- a Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150, Zabolotnogo Str. , Kyiv , 03680 , Ukraine
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20
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Millevoi S, Moine H, Vagner S. G-quadruplexes in RNA biology. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:495-507. [PMID: 22488917 DOI: 10.1002/wrna.1113] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
G-quadruplexes are noncanonical structures formed by G-rich DNA and RNA sequences that fold into a four-stranded conformation. Experimental studies and computational predictions show that RNA G-quadruplexes are present in transcripts associated with telomeres, in noncoding sequences of primary transcripts and within mature transcripts. RNA G-quadruplexes at these specific locations play important roles in key cellular functions, including telomere homeostasis and gene expression. Indeed, RNA G-quadruplexes appear as important regulators of pre-mRNA processing (splicing and polyadenylation), RNA turnover, mRNA targeting and translation. The regulatory mechanisms controlled by RNA G-quadruplexes involve the binding of protein factors that modulate G-quadruplex conformation and/or serve as a bridge to recruit additional protein regulators. In this review, we summarize the current knowledge on the role of G-quadruplexes in RNA biology with particular emphasis on the molecular mechanisms underlying their specific function in RNA metabolism occurring in physiological or pathological conditions.
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Affiliation(s)
- Stefania Millevoi
- Inserm UMR 1037, University of Toulouse III, Cancer Research Center of Toulouse, Toulouse 31432, Cedex 4, France.
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21
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Tian B, Graber JH. Signals for pre-mRNA cleavage and polyadenylation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:385-96. [PMID: 22012871 DOI: 10.1002/wrna.116] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Pre-mRNA cleavage and polyadenylation is an essential step for 3' end formation of almost all protein-coding transcripts in eukaryotes. The reaction, involving cleavage of nascent mRNA followed by addition of a polyadenylate or poly(A) tail, is controlled by cis-acting elements in the pre-mRNA surrounding the cleavage site. Experimental and bioinformatic studies in the past three decades have elucidated conserved and divergent elements across eukaryotes, from yeast to human. Here we review histories and current models of these elements in a broad range of species.
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Affiliation(s)
- Bin Tian
- UMDNJ-New Jersey Medical School, Newark, NJ, USA.
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22
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Bruelle C, Bédard M, Blier S, Gauthier M, Traish AM, Vincent M. The mitotic phosphorylation of p54nrb modulates its RNA binding activity. Biochem Cell Biol 2011; 89:423-33. [DOI: 10.1139/o11-030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The RNA-binding protein p54nrb is involved in many nuclear processes including transcription, RNA processing, and retention of hyperedited RNAs. In interphase cells, p54nrb localizes to the nucleoplasm and concentrates with protein partners in the paraspeckles via an interaction with the non-coding RNA Neat1. During mitosis, p54nrb becomes multiphosphorylated and the effects of this modification are not known. In the present study, we show that p54nrb phosphorylation does not affect the interactions with its protein partners but rather diminishes its general RNA-binding ability. Biochemical assays indicate that in vitro phosphorylation of a GST-p54nrb construct by CDK1 abolishes the interaction with 5′ splice site RNA sequence. Site-directed mutagenesis shows that the threonine 15 residue, located N-terminal to the RRM tandem domains of p54nrb, is involved in this inhibition. In vivo analysis reveals that Neat1 ncRNA co-immunoprecipitates with p54nrb in either interphase or mitotic cells, suggesting that p54nrb–Neat1 interaction is not modulated by phosphorylation. Accordingly, in vitro phosphorylated GST-p54nrb still interacts with PIR-1 RNA, a G-rich Neat1 sequence known to interact with p54nrb. In vitro RNA binding assays show that CDK1-phosphorylation of a GST-p54nrb construct abolishes its interaction with homoribopolymers poly(A), poly(C), and poly(U) but not with poly(G). These data suggest that p54nrb interaction with RNA could be selectively modulated by phosphorylation during mitosis.
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Affiliation(s)
- Céline Bruelle
- PROTEO Research Center and Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Mikaël Bédard
- PROTEO Research Center and Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Stéphanie Blier
- PROTEO Research Center and Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Martin Gauthier
- PROTEO Research Center and Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Abdulmaged M. Traish
- Department of Biochemistry, Boston University School of Medicine, Center for Advanced Biomedical Research, 700 Albany Street, W607, Boston, MA 02118, USA
| | - Michel Vincent
- PROTEO Research Center and Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, QC G1V 0A6, Canada
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Phan AT, Kuryavyi V, Darnell JC, Serganov A, Majumdar A, Ilin S, Raslin T, Polonskaia A, Chen C, Clain D, Darnell RB, Patel DJ. Structure-function studies of FMRP RGG peptide recognition of an RNA duplex-quadruplex junction. Nat Struct Mol Biol 2011; 18:796-804. [PMID: 21642970 PMCID: PMC3130835 DOI: 10.1038/nsmb.2064] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 03/30/2011] [Indexed: 01/22/2023]
Abstract
We have determined the solution structure of the complex between an arginine-glycine-rich RGG peptide from the fragile X mental retardation protein (FMRP) and an in vitro-selected guanine-rich sc1 RNA. The bound RNA forms a novel G-quadruplex separated from the flanking duplex stem by a mixed junctional tetrad. The RGG peptide is positioned along the major groove of the RNA duplex, with the G-quadruplex forcing a sharp turn of R10GGGGR15 at the duplex-quadruplex junction. Arginines R10 and R15 form cross-strand specificity-determining intermolecular hydrogen-bonds with the major-groove edges of guanines of adjacent Watson-Crick G•C pairs. Filter binding assays on RNA and peptide mutations identify and validate contributions of peptide-RNA intermolecular contacts and shape complementarity to molecular recognition. These findings on FMRP RGG domain recognition by a combination of G-quadruplex and surrounding RNA sequences have implications for recognition of other genomic G-rich RNAs.
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Affiliation(s)
- Anh Tuân Phan
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
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Ji X, Sun H, Zhou H, Xiang J, Tang Y, Zhao C. Research Progress of RNA Quadruplex. Nucleic Acid Ther 2011; 21:185-200. [DOI: 10.1089/nat.2010.0272] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Xiaohui Ji
- Key Laboratory for Cell Proliferation and Regulation Biology of Ministry of Education, Beijing Key Laboratory of Gene Engineering Drugs and Biological Technology, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Hongxia Sun
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Huaxi Zhou
- Department of Systems Science, School of Management, Beijing Normal University, Beijing, China
| | - Junfeng Xiang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Yalin Tang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Changqi Zhao
- Key Laboratory for Cell Proliferation and Regulation Biology of Ministry of Education, Beijing Key Laboratory of Gene Engineering Drugs and Biological Technology, College of Life Sciences, Beijing Normal University, Beijing, China
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25
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RNA polymerase II kinetics in polo polyadenylation signal selection. EMBO J 2011; 30:2431-44. [PMID: 21602789 DOI: 10.1038/emboj.2011.156] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 04/11/2011] [Indexed: 01/13/2023] Open
Abstract
Regulated alternative polyadenylation is an important feature of gene expression, but how gene transcription rate affects this process remains to be investigated. polo is a cell-cycle gene that uses two poly(A) signals in the 3' untranslated region (UTR) to produce alternative messenger RNAs that differ in their 3'UTR length. Using a mutant Drosophila strain that has a lower transcriptional elongation rate, we show that transcription kinetics can determine alternative poly(A) site selection. The physiological consequences of incorrect polo poly(A) site choice are of vital importance; transgenic flies lacking the distal poly(A) signal cannot produce the longer transcript and die at the pupa stage due to a failure in the proliferation of the precursor cells of the abdomen, the histoblasts. This is due to the low translation efficiency of the shorter transcript produced by proximal poly(A) site usage. Our results show that correct polo poly(A) site selection functions to provide the correct levels of protein expression necessary for histoblast proliferation, and that the kinetics of RNA polymerase II have an important role in the mechanism of alternative polyadenylation.
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Ji X, Sun H, Zhou H, Xiang J, Tang Y, Zhao C. Research Progress of RNA Quadruplex. Oligonucleotides 2011:121102072334007. [PMID: 21574857 DOI: 10.1089/oli.2010.0272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
RNA/DNA sequences rich in guanine (G) can form a 4-strand structure, G-quadruplex, which has been extensively researched and observed in mammalian, fungi, and plants, with in vivo existence in eukaryotic cells. Compared with DNA quadruplex, the potential existence of RNA quadruplex appears to be generally rare; however, it is believed by some researchers to be more inevitable in vivo and speculated to play an important role where it exists. Recently, researches concerning the function of G-quadruplexes in RNAs commence, making much progress. However, there is no available review particularly focusing on RNA quadruplex till now as we know. Therefore, we decide to give a review to comprehensively summarize research progress on it. This review highlights the diverse topologies for RNA quadruplex structure and its effect factors; outlines the current knowledge of RNA quadruplex's physiological functions in biological systems, especially in gene expression; and presents the prospects of RNA quadruplex.
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Affiliation(s)
- Xiaohui Ji
- 1 Key Laboratory for Cell Proliferation and Regulation Biology of Ministry of Education, Beijing Key Laboratory of Gene Engineering Drugs and Biological Technology, College of Life Sciences, Beijing Normal University , Beijing, China
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27
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Abstract
Messenger RNAs undergo 5' capping, splicing, 3'-end processing, and export before translation in the cytoplasm. It has become clear that these mRNA processing events are tightly coupled and have a profound effect on the fate of the resulting transcript. This processing is represented by modifications of the pre-mRNA and loading of various protein factors. The sum of protein factors that stay with the mRNA as a result of processing is modified over the life of the transcript, conferring significant regulation to its expression.
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Affiliation(s)
- Sami Hocine
- Department for Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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28
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Lutz CS, Moreira A. Alternative mRNA polyadenylation in eukaryotes: an effective regulator of gene expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 2:22-31. [PMID: 21956967 DOI: 10.1002/wrna.47] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Alternative RNA processing mechanisms, including alternative splicing and alternative polyadenylation, are increasingly recognized as important regulators of gene expression. This article will focus on what has recently been described about alternative polyadenylation in development, differentiation, and disease in higher eukaryotes. We will also describe how the evolving global methodologies for examining the cellular transcriptome, both experimental and bioinformatic, are revealing new details about the complex nature of alternative 3(') end formation as well as interactions with other RNA-mediated and RNA processing mechanisms.
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Affiliation(s)
- Carol S Lutz
- Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, Newark, NJ, USA.
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The Arabidopsis ortholog of the 77 kDa subunit of the cleavage stimulatory factor (AtCstF-77) involved in mRNA polyadenylation is an RNA-binding protein. FEBS Lett 2010; 584:1449-54. [PMID: 20214900 DOI: 10.1016/j.febslet.2010.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/23/2010] [Accepted: 03/03/2010] [Indexed: 01/27/2023]
Abstract
The 77 kDa subunit of the polyadenylation cleavage stimulation factor (CstF77) is important in messenger RNA 3' end processing. Previously, we demonstrated that AtCstF77 interacts with AtCPSF30, the Arabidopsis ortholog of the 30 kDa subunit of the Cleavage and Polyadenylation Specificity Factor. In further dissecting this interaction, it was found that the C-terminus of AtCstF77 interacts with AtCPSF30. Remarkably, we also found that the C-terminal domain of AtCstF77 possesses RNA-binding ability. These studies therefore reveal AtCstF77 to be an RNA-binding protein, adding yet another RNA-binding activity to the plant polyadenylation complex. This raises interesting questions as to the means by which RNAs are recognized during mRNA 3' end formation in plants.
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30
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Millevoi S, Vagner S. Molecular mechanisms of eukaryotic pre-mRNA 3' end processing regulation. Nucleic Acids Res 2009; 38:2757-74. [PMID: 20044349 PMCID: PMC2874999 DOI: 10.1093/nar/gkp1176] [Citation(s) in RCA: 294] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Messenger RNA (mRNA) 3′ end formation is a nuclear process through which all eukaryotic primary transcripts are endonucleolytically cleaved and most of them acquire a poly(A) tail. This process, which consists in the recognition of defined poly(A) signals of the pre-mRNAs by a large cleavage/polyadenylation machinery, plays a critical role in gene expression. Indeed, the poly(A) tail of a mature mRNA is essential for its functions, including stability, translocation to the cytoplasm and translation. In addition, this process serves as a bridge in the network connecting the different transcription, capping, splicing and export machineries. It also participates in the quantitative and qualitative regulation of gene expression in a variety of biological processes through the selection of single or alternative poly(A) signals in transcription units. A large number of protein factors associates with this machinery to regulate the efficiency and specificity of this process and to mediate its interaction with other nuclear events. Here, we review the eukaryotic 3′ end processing machineries as well as the comprehensive set of regulatory factors and discuss the different molecular mechanisms of 3′ end processing regulation by proposing several overlapping models of regulation.
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Affiliation(s)
- Stefania Millevoi
- Institut National de la Santé et de la Recherche Médicale U563, Toulouse, F-31000, France.
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31
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Millevoi S, Decorsière A, Loulergue C, Iacovoni J, Bernat S, Antoniou M, Vagner S. A physical and functional link between splicing factors promotes pre-mRNA 3' end processing. Nucleic Acids Res 2009; 37:4672-83. [PMID: 19506027 PMCID: PMC2724285 DOI: 10.1093/nar/gkp470] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Polypyrimidine tract-binding protein (PTB) is a splicing regulator that also plays a positive role in pre-mRNA 3' end processing when bound upstream of the polyadenylation signal (pA signal). Here, we address the mechanism of PTB stimulatory function in mRNA 3' end formation. We identify PTB as the protein factor whose binding to the human beta-globin (HBB) 3' UTR is abrogated by a 3' end processing-inactivating mutation. We show that PTB promotes both in vitro 3' end cleavage and polyadenylation and recruits directly the splicing factor hnRNP H to G-rich sequences associated with several pA signals. Increased binding of hnRNP H results in stimulation of polyadenylation through a direct interaction with poly(A) polymerase. Therefore, our results provide evidence of a concerted regulation of pA signal recognition by splicing factors bound to auxiliary polyadenylation sequence elements.
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Affiliation(s)
- Stefania Millevoi
- INSERM, U563, Toulouse, Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan, Toulouse, F-31300, France.
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32
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Abstract
Regulation of gene expression by RNA processing mechanisms is now understood to be an important level of control in mammalian cells. Regulation at the level of RNA transcription, splicing, polyadenylation, nucleo-cytoplasmic transport, and translation into polypeptides has been well-studied. Alternative RNA processing events, such as alternative splicing, also have been recognized as key contributors to the complexity of mammalian gene expression. Pre-messenger RNAs (pre-mRNAs) may be polyadenylated in several different ways due to more than one polyadenylation signal, allowing a single gene to encode multiple mRNA transcripts. However, alternative polyadenylation has only recently taken the field as a major player in gene regulation. This review summarizes what is currently known about alternative polyadenylation. It covers results from bioinformatics, as well as those from investigations of viral and tissue-specific studies and, importantly, will set the stage for what is yet to come.
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Affiliation(s)
- Carol S. Lutz
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey−New Jersey Medical School, MSB E671, 185 South Orange Avenue, Newark, New Jersey 07101
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Maciolek NL, McNally MT. Characterization of Rous sarcoma virus polyadenylation site use in vitro. Virology 2008; 374:468-76. [PMID: 18272196 PMCID: PMC2413101 DOI: 10.1016/j.virol.2008.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 12/13/2007] [Accepted: 01/10/2008] [Indexed: 11/22/2022]
Abstract
Polyadenylation of Rous sarcoma virus (RSV) RNA is inefficient, as approximately 15% of RSV RNAs represent read-through transcripts that use a downstream cellular polyadenylation site (poly(A) site). Read-through transcription has implications for the virus and the host since it is associated with oncogene capture and tumor induction. To explore the basis of inefficient RSV RNA 3'-end formation, we characterized RSV polyadenylation in vitro using HeLa cell nuclear extracts and HEK293 whole cell extracts. RSV polyadenylation substrates composed of the natural 3' end of viral RNA and various lengths of upstream sequence showed little or no polyadenylation, indicating that the RSV poly(A) site is suboptimal. Efficiently used poly(A) sites often have identifiable upstream and downstream elements (USEs and DSEs) in close proximity to the conserved AAUAAA signal. The sequences upstream and downstream of the RSV poly(A) site deviate from those found in efficiently used poly(A) sites, which may explain inefficient RSV polyadenylation. To assess the quality of the RSV USEs and DSEs, the well-characterized SV40 late USEs and/or DSEs were substituted for the RSV elements and vice versa, which showed that the USEs and DSEs from RSV are suboptimal but functional. CstF interacted poorly with the RSV polyadenylation substrate, and the inactivity of the RSV poly(A) site was at least in part due to poor CstF binding since tethering CstF to the RSV substrate activated polyadenylation. Our data are consistent with poor polyadenylation factor binding sites in both the USE and DSE as the basis for inefficient use of the RSV poly(A) site and point to the importance of additional elements within RSV RNA in promoting 3' end formation.
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Affiliation(s)
- Nicole L. Maciolek
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701, Watertown Plank Road, Milwaukee, WI 53226 USA
| | - Mark T. McNally
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701, Watertown Plank Road, Milwaukee, WI 53226 USA
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34
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Abstract
Upon integration into the host chromosome, retroviral gene expression requires transcription by the host RNA polymerase II, and viral messages are subject RNA processing events including 5'-end capping, pre-mRNA splicing, and polyadenylation. At a minimum, RNA splicing is required to generate the env mRNA, but viral replication requires substantial amounts of unspliced RNA to serve as mRNA and for incorporation into progeny virions as genomic RNA. Therefore, splicing has to be controlled to preserve the large unspliced RNA pool. Considering the current view that splicing and polyadenylation are coupled, the question arises as to how genome-length viral RNA is efficiently polyadenylated in the absence of splicing. Polyadenylation of many retroviral mRNAs is inefficient; in avian retroviruses, approximately 15 percent of viral transcripts extend into and are polyadenylated at downstream host genes, which often has profound biological consequences. Retroviruses have served as important models to study RNA processing and this review summarizes a body of work using avian retroviruses that has led to the discovery of novel RNA splicing and polyadenylation control mechanisms.
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Affiliation(s)
- Mark T McNally
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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35
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Abstract
Most eukaryotic mRNA precursors (premRNAs) must undergo extensive processing, including cleavage and polyadenylation at the 3'-end. Processing at the 3'-end is controlled by sequence elements in the pre-mRNA (cis elements) as well as protein factors. Despite the seeming biochemical simplicity of the processing reactions, more than 14 proteins have been identified for the mammalian complex, and more than 20 proteins have been identified for the yeast complex. The 3'-end processing machinery also has important roles in transcription and splicing. The mammalian machinery contains several sub-complexes, including cleavage and polyadenylation specificity factor, cleavage stimulation factor, cleavage factor I, and cleavage factor II. Additional protein factors include poly(A) polymerase, poly(A)-binding protein, symplekin, and the C-terminal domain of RNA polymerase II largest subunit. The yeast machinery includes cleavage factor IA, cleavage factor IB, and cleavage and polyadenylation factor.
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Affiliation(s)
- C. R. Mandel
- Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - Y. Bai
- Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - L. Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027 USA
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36
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Kikin O, Zappala Z, D'Antonio L, Bagga PS. GRSDB2 and GRS_UTRdb: databases of quadruplex forming G-rich sequences in pre-mRNAs and mRNAs. Nucleic Acids Res 2007; 36:D141-8. [PMID: 18045785 PMCID: PMC2238929 DOI: 10.1093/nar/gkm982] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
G-quadruplex motifs in the RNA play significant roles in key cellular processes and human disease. While sequences capable of forming G-quadruplexes in the pre-mRNA are involved in regulation of polyadenylation and splicing events in mammalian transcripts, the G-quadruplex motifs in the UTRs may help regulate mRNA expression. GRSDB2 is a second-generation database containing information on the composition and distribution of putative Quadruplex-forming G-Rich Sequences (QGRS) mapped in ∼29 000 eukaryotic pre-mRNA sequences, many of which are alternatively processed. The data stored in the GRSDB2 is based on computational analysis of NCBI Entrez Gene entries with the help of an improved version of the QGRS Mapper program. The database allows complex queries with a wide variety of parameters, including Gene Ontology terms. The data is displayed in a variety of formats with several additional computational capabilities. We have also developed a new database, GRS_UTRdb, containing information on the composition and distribution patterns of putative QGRS in the 5′- and 3′-UTRs of eukaryotic mRNA sequences. The goal of these experiments has been to build freely accessible resources for exploring the role of G-quadruplex structure in regulation of gene expression at post-transcriptional level. The databases can be accessed at the G-Quadruplex Resource Site at: http://bioinformatics.ramapo.edu/GQRS/.
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Affiliation(s)
- Oleg Kikin
- Bergen County Academies, Hackensack and Bioinformatics, School of Theoretical and Applied Science, Ramapo College of New Jersey, Mahwah, NJ, USA
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37
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Dalziel M, Nunes NM, Furger A. Two G-rich regulatory elements located adjacent to and 440 nucleotides downstream of the core poly(A) site of the intronless melanocortin receptor 1 gene are critical for efficient 3' end processing. Mol Cell Biol 2006; 27:1568-80. [PMID: 17189425 PMCID: PMC1820467 DOI: 10.1128/mcb.01821-06] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cleavage and polyadenylation is an essential processing reaction required for the maturation of pre-mRNAs into stable, export- and translation-competent mature mRNA molecules. This reaction requires the assembly of a multimeric protein complex onto a bipartite core sequence element consisting of an AAUAAA hexamer and a GU/U-rich downstream sequence element. In this study we have analyzed 3' end processing of the human melanocortin 1 receptor gene (MC1R). The MC1R gene is an intron-free transcription unit, and its poly(A) site lacks a defined U/GU-rich element. We describe two G-rich sequence elements that are critical for efficient cleavage at the MC1R poly(A) site. The first element is located 30 nucleotides downstream of the cleavage site and acts as an essential closely positioned enhancer. The second G-rich region is positioned more than 440 nucleotides downstream of the MC1R processing site and is instrumental for optimal processing efficiency. Both G-rich sequences contain clusters of heterogeneous nuclear ribonucleoprotein binding motifs and act together to enhance cleavage at the MC1R poly(A) site.
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Affiliation(s)
- Martin Dalziel
- Genetics Unit, Department of Biochemistry, South Parks Road, Oxford OX1 3QU, United Kingdom
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38
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Liu D, Brockman JM, Dass B, Hutchins LN, Singh P, McCarrey JR, MacDonald CC, Graber JH. Systematic variation in mRNA 3'-processing signals during mouse spermatogenesis. Nucleic Acids Res 2006; 35:234-46. [PMID: 17158511 PMCID: PMC1802579 DOI: 10.1093/nar/gkl919] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Gene expression and processing during mouse male germ cell maturation (spermatogenesis) is highly specialized. Previous reports have suggested that there is a high incidence of alternative 3′-processing in male germ cell mRNAs, including reduced usage of the canonical polyadenylation signal, AAUAAA. We used EST libraries generated from mouse testicular cells to identify 3′-processing sites used at various stages of spermatogenesis (spermatogonia, spermatocytes and round spermatids) and testicular somatic Sertoli cells. We assessed differences in 3′-processing characteristics in the testicular samples, compared to control sets of widely used 3′-processing sites. Using a new method for comparison of degenerate regulatory elements between sequence samples, we identified significant changes in the use of putative 3′-processing regulatory sequence elements in all spermatogenic cell types. In addition, we observed a trend towards truncated 3′-untranslated regions (3′-UTRs), with the most significant differences apparent in round spermatids. In contrast, Sertoli cells displayed a much smaller trend towards 3′-UTR truncation and no significant difference in 3′-processing regulatory sequences. Finally, we identified a number of genes encoding mRNAs that were specifically subject to alternative 3′-processing during meiosis and postmeiotic development. Our results highlight developmental differences in polyadenylation site choice and in the elements that likely control them during spermatogenesis.
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Affiliation(s)
- Donglin Liu
- The Jackson Laboratory, 600 Main StreetBar Harbor, ME 04609, USA
| | - J. Michael Brockman
- The Jackson Laboratory, 600 Main StreetBar Harbor, ME 04609, USA
- Bioinformatics Program, Boston University24 Cummington Street, Boston, MA 02215, USA
| | - Brinda Dass
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX 79430, USA
| | | | - Priyam Singh
- The Jackson Laboratory, 600 Main StreetBar Harbor, ME 04609, USA
- Bioinformatics Program, Boston University24 Cummington Street, Boston, MA 02215, USA
| | - John R. McCarrey
- Department of Biology, University of Texas at San AntonioSan Antonio, TX 78249, USA
| | - Clinton C. MacDonald
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX 79430, USA
| | - Joel H. Graber
- The Jackson Laboratory, 600 Main StreetBar Harbor, ME 04609, USA
- Bioinformatics Program, Boston University24 Cummington Street, Boston, MA 02215, USA
- To whom correspondence should be addressed. Tel: +1 207 288 6847; Fax: +1 207 288 6073;
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McMahon KW, Hirsch BA, MacDonald CC. Differences in polyadenylation site choice between somatic and male germ cells. BMC Mol Biol 2006; 7:35. [PMID: 17038175 PMCID: PMC1618850 DOI: 10.1186/1471-2199-7-35] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Accepted: 10/12/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We have previously noted that there were differences in somatic and male germ cell polyadenylation site choices. First, male germ cells showed a lower incidence of the sequence AAUAAA (an important element for somatic polyadenylation site choice) near the polyadenylation site choice. Second, the polyadenylation sites chosen in male germ cells tended to be nearer the 5' end of the mRNA than those chosen in somatic cells. Finally, a number of mRNAs used a different polyadenylation site in male germ cells than in somatic cells. These differences suggested that male germ cell-specific polyadenylation sites may be poor substrates for polyadenylation in somatic cells. We therefore hypothesized that male germ cell-specific polyadenylation sites would be inefficiently used in somatic cells. RESULTS We tested whether pre-mRNA sequences surrounding male germ cell-specific polyadenylation sites (polyadenylation cassettes) could be used to direct polyadenylation efficiently in somatic cells. To do this, we developed a luciferase reporter system in which luciferase activity correlated with polyadenylation efficiency. We showed that in somatic cells, somatic polyadenylation cassettes were efficiently polyadenylated, while male germ cell-specific polyadenylation cassettes were not. We also developed a sensitive, 3' RACE-based assay to analyze polyadenylation site choice. Using this assay, we demonstrated that male germ cell-specific polyadenylation cassettes were not polyadenylated at the expected site in somatic cells, but rather at aberrant sites upstream of the sites used in male germ cells. Finally, mutation of the male germ cell-specific poly(A) signal to a somatic poly(A) signal resulted in more efficient polyadenylation in somatic cells. CONCLUSION These data suggest that regulated polyadenylation site choice of male germ cell-specific polyadenylation sites requires one or more factors that are absent from somatic cells.
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Affiliation(s)
- K Wyatt McMahon
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4St, Lubbock, TX 79430-6540 USA
| | - Benjamin A Hirsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4St, Lubbock, TX 79430-6540 USA
| | - Clinton C MacDonald
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4St, Lubbock, TX 79430-6540 USA
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40
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Kikin O, D'Antonio L, Bagga PS. QGRS Mapper: a web-based server for predicting G-quadruplexes in nucleotide sequences. Nucleic Acids Res 2006; 34:W676-82. [PMID: 16845096 PMCID: PMC1538864 DOI: 10.1093/nar/gkl253] [Citation(s) in RCA: 661] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The quadruplex structures formed by guanine-rich nucleic acid sequences have received significant attention recently because of growing evidence for their role in important biological processes and as therapeutic targets. G-quadruplex DNA has been suggested to regulate DNA replication and may control cellular proliferation. Sequences capable of forming G-quadruplexes in the RNA have been shown to play significant roles in regulation of polyadenylation and splicing events in mammalian transcripts. Whether quadruplex structure directly plays a role in regulating RNA processing requires investigation. Computational approaches to study G-quadruplexes allow detailed analysis of mammalian genomes. There are no known easily accessible user-friendly tools that can compute G-quadruplexes in the nucleotide sequences. We have developed a web-based server, QGRS Mapper, that predicts quadruplex forming G-rich sequences (QGRS) in nucleotide sequences. It is a user-friendly application that provides many options for defining and studying G-quadruplexes. It performs analysis of the user provided genomic sequences, e.g. promoter and telomeric regions, as well as RNA sequences. It is also useful for predicting G-quadruplex structures in oligonucleotides. The program provides options to search and retrieve desired gene/nucleotide sequence entries from NCBI databases for mapping G-quadruplexes in the context of RNA processing sites. This feature is very useful for investigating the functional relevance of G-quadruplex structure, in particular its role in regulating the gene expression by alternative processing. In addition to providing data on composition and locations of QGRS relative to the processing sites in the pre-mRNA sequence, QGRS Mapper features interactive graphic representation of the data. The user can also use the graphics module to visualize QGRS distribution patterns among all the alternative RNA products of a gene simultaneously on a single screen. QGRS Mapper can be accessed at .
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Affiliation(s)
| | | | - Paramjeet S Bagga
- To whom correspondence should be addressed. Tel: +1 201 684 7722; Fax: +1 201 684 7637;
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41
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Huber Z, Monarez RR, Dass B, MacDonald CC. The mRNA encoding tauCstF-64 is expressed ubiquitously in mouse tissues. Ann N Y Acad Sci 2006; 1061:163-72. [PMID: 16467265 DOI: 10.1196/annals.1336.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Polyadenylation is a process of endonucleolytic cleavage of the mRNA, followed by addition of up to 250 adenosine residues to the 3' end of the mRNA. Polyadenylation is essential for eukaryotic mRNA expression, and CstF-64 is a subunit of the CstF polyadenylation factor that is required for accurate polyadenylation. We discovered that there are two forms of the CstF-64 protein in mammalian male germ cells, one of which (CstF-64) is expressed in all tissues, the other of which (tauCstF-64) is expressed only in male germ cells and in brain (albeit at significantly lower levels in the brain). Therefore, we were surprised to find that, using reverse transcription-PCR, cDNA cloning, and RNA blot analyses, tauCstF-64 mRNA was expressed at higher levels in brain than in testis. Also, tauCstF-64 mRNA was expressed at lower but detectable levels in all tissues tested, including epididymis, heart, kidney, liver, lung, muscle, ovary, spleen, thymus, and uterus. These results suggest the hypothesis that tauCstF-64 mRNA is regulated at the translational or post-translational level.
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Affiliation(s)
- Zane Huber
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
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42
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Salisbury J, Hutchison KW, Graber JH. A multispecies comparison of the metazoan 3'-processing downstream elements and the CstF-64 RNA recognition motif. BMC Genomics 2006; 7:55. [PMID: 16542450 PMCID: PMC1539018 DOI: 10.1186/1471-2164-7-55] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 03/16/2006] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The Cleavage Stimulation Factor (CstF) is a required protein complex for eukaryotic mRNA 3'-processing. CstF interacts with 3'-processing downstream elements (DSEs) through its 64-kDa subunit, CstF-64; however, the exact nature of this interaction has remained unclear. We used EST-to-genome alignments to identify and extract large sets of putative 3'-processing sites for mRNA from ten metazoan species, including Homo sapiens, Canis familiaris, Rattus norvegicus, Mus musculus, Gallus gallus, Danio rerio, Takifugu rubripes, Drosophila melanogaster, Anopheles gambiae, and Caenorhabditis elegans. In order to further delineate the details of the mRNA-protein interaction, we obtained and multiply aligned CstF-64 protein sequences from the same species. RESULTS We characterized the sequence content and specific positioning of putative DSEs across the range of organisms studied. Our analysis characterized the downstream element (DSE) as two distinct parts - a proximal UG-rich element and a distal U-rich element. We find that while the U-rich element is largely conserved in all of the organisms studied, the UG-rich element is not. Multiple alignment of the CstF-64 RNA recognition motif revealed that, while it is highly conserved throughout metazoans, we can identify amino acid changes that correlate with observed variation in the sequence content and positioning of the DSEs. CONCLUSION Our analysis confirms the early reports of separate U- and UG-rich DSEs. The correlated variations in protein sequence and mRNA binding sequences provide novel insights into the interactions between the precursor mRNA and the 3'-processing machinery.
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Affiliation(s)
- Jesse Salisbury
- Functional Genomics Program, The University of Maine, Orono, Maine 04469, USA
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
| | - Keith W Hutchison
- Functional Genomics Program, The University of Maine, Orono, Maine 04469, USA
- Department of Biochemistry, Microbiology and Molecular Biology, The University of Maine, Orono, ME 04469, USA
| | - Joel H Graber
- Functional Genomics Program, The University of Maine, Orono, Maine 04469, USA
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
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43
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Alkan S, Martincic K, Milcarek C. The hnRNPs F and H2 bind to similar sequences to influence gene expression. Biochem J 2006; 393:361-71. [PMID: 16171461 PMCID: PMC1383695 DOI: 10.1042/bj20050538] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The hnRNPs (heterogeneous nuclear ribonucleoproteins) F and H2 share a similar protein structure. Both have been implicated as regulating polyadenylation, but hnRNP H2 had a positive effect, whereas hnRNP F acted negatively. We therefore carried out side-by-side comparisons of their RNA-binding and in vivo actions. The binding of the CstF2 (64 kDa cleavage stimulatory factor) to SV40 (simian virus 40) late pre-mRNA substrates containing a downstream GRS (guanine-rich sequence) was reduced by hnRNP F, but not by hnRNP H2, in a UV-cross-linking assay. Point mutations of the 14-nt GRS influenced the binding of purified hnRNP F or H2 in parallel. Co-operative binding of the individual proteins to RNA was lost with mutations of the GRS in the G1-5 or G12-14 regions; both regions seem to be necessary for optimal interactions. Using a reporter green fluorescent protein assay with the GRS inserted downstream of the poly(A) (polyadenine) signal, expression in vivo was diminished by a mutant G1-5 sequence which decreased binding of both hnRNPs (SAA20) and was enhanced by a 12-14-nt mutant that showed enhanced hnRNP F or H2 binding (SAA10). Using small interfering RNA, down-regulation of hnRNP H2 levels diminished reporter expression, confirming that hnRNP H2 confers a positive influence; in contrast, decreasing hnRNP F levels had a negligible influence on reporter expression with the intact GRS. A pronounced diminution in reporter expression was seen with the SAA20 mutant for both. Thus the relative levels of hnRNP F and H2 in cells, as well as the target sequences in the downstream GRS on pre-mRNA, influence gene expression.
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Affiliation(s)
- Serkan A. Alkan
- *Program in Biochemistry and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
- †Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Kathleen Martincic
- †Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Christine Milcarek
- †Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
- To whom correspondence should be addressed (email )
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Kostadinov R, Malhotra N, Viotti M, Shine R, D'Antonio L, Bagga P. GRSDB: a database of quadruplex forming G-rich sequences in alternatively processed mammalian pre-mRNA sequences. Nucleic Acids Res 2006; 34:D119-24. [PMID: 16381828 PMCID: PMC1347436 DOI: 10.1093/nar/gkj073] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Guanine-rich nucleic acids are known to form highly stable G-quadruplex structures, also known as G-quartets. Recently, there has been a tremendous amount of interest in studying G-quadruplexes owing to the realization of their biological importance. G-rich sequences (GRSs) capable of forming G-quadruplexes are found in the vicinity of polyadenylation regions and are involved in regulating 3′ end processing of mammalian pre-mRNAs. G-rich motifs are also known to play an important role in alternative, tissue-specific splicing by interacting with hnRNP H protein subfamily. Whether quadruplex structure directly plays a role in regulating RNA processing events requires further investigation. To date there has not been a comprehensive effort to study G-quadruplexes near RNA processing sites. We have applied a computational approach to map putative Quadruplex forming GRSs within the transcribed regions of a large number of alternatively processed human and mouse gene sequences that were obtained as fully annotated entries from GenBank and RefSeq. We have used the computed data to build the GRSDB database that provides a unique avenue for studying G-quadruplexes in the context of RNA processing sites. GRSDB website offers visual comparison of G-quadruplex distribution patterns among all the alternative RNA products of a gene with the help of dynamic graphics. At present, GRSDB contains data from 1310 human and mouse genes, of which 1188 are alternatively processed. It has a total of 379 223 predicted G-quadruplexes, of which 54 252 are near RNA processing sites. GRSDB is a good resource for researchers interested in investigating the functional relevance of G-quadruplexes, especially in the context of alternative RNA processing. It can be accessed at .
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Affiliation(s)
| | | | | | | | | | - Paramjeet Bagga
- To whom correspondence should be addressed. Tel: +1 201 684 7722; Fax: +1 201 684 7637;
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Rigo F, Kazerouninia A, Nag A, Martinson HG. The RNA tether from the poly(A) signal to the polymerase mediates coupling of transcription to cleavage and polyadenylation. Mol Cell 2006; 20:733-45. [PMID: 16337597 DOI: 10.1016/j.molcel.2005.09.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 09/15/2005] [Accepted: 09/30/2005] [Indexed: 11/15/2022]
Abstract
We have investigated the mechanism by which transcription accelerates cleavage and polyadenylation in vitro. By using a coupled transcription-processing system, we show that rapid and efficient 3' end processing occurs in the absence of crowding agents like polyvinyl alcohol. The continuity of the RNA from the poly(A) signal down to the polymerase is critical to this processing. If this tether is cut with DNA oligonucleotides and RNaseH during transcription, the efficiency of processing is drastically reduced. The polymerase is known to be an integral part of the cleavage and polyadenylation apparatus. RNA polymerase II pull-down and immobilized template experiments suggest that the role of the tether is to hold the poly(A) signal close to the polymerase during the early stages of processing complex assembly until the complex is sufficiently mature to remain stably associated with the polymerase on its own.
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Affiliation(s)
- Frank Rigo
- Department of Chemistry and Biochemistry and The Molecular Biology Institute, University of California, Los Angeles, 90095, USA
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Hu J, Lutz CS, Wilusz J, Tian B. Bioinformatic identification of candidate cis-regulatory elements involved in human mRNA polyadenylation. RNA (NEW YORK, N.Y.) 2005; 11:1485-93. [PMID: 16131587 PMCID: PMC1370832 DOI: 10.1261/rna.2107305] [Citation(s) in RCA: 181] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Polyadenylation is an essential step for the maturation of almost all cellular mRNAs in eukaryotes. In human cells, most poly(A) sites are flanked by the upstream AAUAAA hexamer or a close variant, and downstream U/GU-rich elements. In yeast and plants, additional cis elements have been found to be located upstream of the poly(A) site, including UGUA, UAUA, and U-rich elements. In this study, we have developed a computer program named PROBE (Polyadenylation-Related Oligonucleotide Bidimensional Enrichment) to identify cis elements that may play regulatory roles in mRNA polyadenylation. By comparing human genomic sequences surrounding frequently used poly(A) sites with those surrounding less frequently used ones, we found that cis elements occurring in yeast and plants also exist in human poly(A) regions, including the upstream U-rich elements, and UAUA and UGUA elements. In addition, several novel elements were found to be associated with human poly(A) sites, including several G-rich elements. Thus, we suggest that many cis elements are evolutionarily conserved among eukaryotes, and human poly(A) sites have an additional set of cis elements that may be involved in the regulation of mRNA polyadenylation.
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Affiliation(s)
- Jun Hu
- Department of Biochemistry and Molecular Biology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07101, USA
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Pan B, Shi K, Sundaralingam M. Synthesis, Purification and Crystallization of Guanine-rich RNA Oligonucleotides. Biol Proced Online 2004; 6:257-262. [PMID: 15562298 PMCID: PMC531606 DOI: 10.1251/bpo96] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 10/22/2004] [Accepted: 11/02/2004] [Indexed: 11/23/2022] Open
Abstract
Guanine-rich RNA oligonucleotides display many novel structural motifs in recent crystal structures. Here we describe the procedures of the chemical synthesis and the purification of such RNA molecules that are suitable for X-ray crystallographic studies. Modifications of the previous purification methods allow us to obtain better yields in shorter time. We also provide 24 screening conditions that are very effective in crystallization of the guanine-rich RNA oligonucleotides. Optimal crystallization conditions are usually achieved by adjustment of the concentration of the metal ions and pH of the buffer. Crystals obtained by this method usually diffract to high resolution.
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Affiliation(s)
- Baocheng Pan
- Departments of Chemistry and Biochemistry, The Ohio State University. 200 Johnston Laboratory, Columbus, OH 43210. USA
| | - Ke Shi
- Departments of Chemistry and Biochemistry, The Ohio State University. 200 Johnston Laboratory, Columbus, OH 43210. USA
| | - Muttaiya Sundaralingam
- Departments of Chemistry and Biochemistry, The Ohio State University. 200 Johnston Laboratory, Columbus, OH 43210. USA
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Fritz DT, Liu D, Xu J, Jiang S, Rogers MB. Conservation of Bmp2 post-transcriptional regulatory mechanisms. J Biol Chem 2004; 279:48950-8. [PMID: 15358784 DOI: 10.1074/jbc.m409620200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bone morphogenetic protein (BMP) orthologs from diverse species like flies and humans are functionally interchangeable and play key roles in fundamental processes such as dorso-ventral axis formation in metazoans. Because both transcriptional and post-transcriptional mechanisms play central roles in modulating developmental protein levels, we have analyzed the 3'-untranslated region (3'UTR) of the Bmp 2 gene. This 3'UTR is unusually long and is alternatively polyadenylated. Mouse, human, and dog mRNAs are 83-87% identical within this region. A 265-nucleotide sequence, conserved between mammals, birds, frogs, and fish, is present in Bmp2 but not Bmp4. The ability of AmphiBMP2/4, a chordate ortholog to Bmp2 and Bmp4, to align with this sequence suggests that its function may have been lost in Bmp4. Activation of reporter genes by the conserved region acts by a post-transcriptional mechanism. Mouse, human, chick, and zebrafish Bmp2 synthetic RNAs decay rapidly in extracts from cells not expressing Bmp2. In contrast, these RNAs are relatively stable in extracts from Bmp2-expressing cells. Thus, Bmp2 RNA half-lives in vitro correlate with natural Bmp2 mRNA levels. The fact that non-murine RNAs interact appropriately with the mouse decay machinery suggests that the function of these cis-regulatory regions has been conserved for 450 million years since the fish and tetrapod lineages diverged. Overall, our results suggest that the Bmp2 3'UTR contains essential regulatory elements that act post-transcriptionally.
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Affiliation(s)
- David T Fritz
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey (UMDNJ)-NJ Medical School, Newark, New Jersey 07101, USA
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Pan B, Xiong Y, Shi K, Sundaralingam M. Crystal structure of a bulged RNA tetraplex at 1.1 a resolution: implications for a novel binding site in RNA tetraplex. Structure 2004; 11:1423-30. [PMID: 14604532 DOI: 10.1016/j.str.2003.09.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Bulges are an important structural motif in RNA and can be used as recognition and interaction sites in RNA-protein interaction and RNA-RNA interaction. Here we report the first crystal structure of a bulged RNA tetraplex at 1.1 A resolution. The hexamer r(U)(BrdG)r(UGGU) forms a parallel tetraplex with the uridine sandwiched by guanines bulging out. The bulged uridine adopts the syn glycosidic conformation and its O2 and N3 atoms face outwards, serving as an effective recognition and interaction site. The bulge formation both widens the groove width and changes the groove hydrogen-bonding pattern on its 5' side. However, the bulge does not make any bends or kinks in the tetraplex structure. The present study demonstrates the dramatic difference between uridine and guanine in forming tetraplex structure. In addition, both G(syn) tetrad and G(anti) tetrad have been observed. They display the same base-pairing pattern and similar C1'-C1' distance but different hydrogen-bonding patterns in the groove.
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Affiliation(s)
- Baocheng Pan
- Department of Chemistry and Biochemistry, The Ohio State University, 200 Johnston Lab, 176 West 19th Avenue, Columbus, OH, USA
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50
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Park NJ, Tsao DC, Martinson HG. The two steps of poly(A)-dependent termination, pausing and release, can be uncoupled by truncation of the RNA polymerase II carboxyl-terminal repeat domain. Mol Cell Biol 2004; 24:4092-103. [PMID: 15121832 PMCID: PMC400489 DOI: 10.1128/mcb.24.10.4092-4103.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The carboxyl-terminal repeat domain (CTD) of RNA polymerase II is thought to help coordinate events during RNA metabolism. The mammalian CTD consists of 52 imperfectly repeated heptads followed by 10 additional residues at the C terminus. The CTD is required for cleavage and polyadenylation in vitro. We studied poly(A)-dependent termination in vivo using CTD truncation mutants. Poly(A)-dependent termination occurs in two steps, pause and release. We found that the CTD is required for release, the first 25 heptads being sufficient. Neither the final 10 amino acids nor the variant heptads of the second half of the CTD were required. No part of the CTD was required for poly(A)-dependent pausing--the poly(A) signal could communicate directly with the body of the polymerase. By removing the CTD, pausing could be observed without being obscured by release. Poly(A)-dependent pausing appeared to operate by slowing down the polymerase, such as by down-regulation of a positive elongation factor. Although the first 25 heptads supported undiminished poly(A)-dependent termination, they did not efficiently support events near the promoter involved in abortive elongation. However, the second half of the CTD, including the final 10 amino acids, was sufficient for these functions.
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Affiliation(s)
- Noh Jin Park
- Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095-1569, USA
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