1
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Ledvina HE, Whiteley AT. Conservation and similarity of bacterial and eukaryotic innate immunity. Nat Rev Microbiol 2024; 22:420-434. [PMID: 38418927 DOI: 10.1038/s41579-024-01017-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2024] [Indexed: 03/02/2024]
Abstract
Pathogens are ubiquitous and a constant threat to their hosts, which has led to the evolution of sophisticated immune systems in bacteria, archaea and eukaryotes. Bacterial immune systems encode an astoundingly large array of antiviral (antiphage) systems, and recent investigations have identified unexpected similarities between the immune systems of bacteria and animals. In this Review, we discuss advances in our understanding of the bacterial innate immune system and highlight the components, strategies and pathogen restriction mechanisms conserved between bacteria and eukaryotes. We summarize evidence for the hypothesis that components of the human immune system originated in bacteria, where they first evolved to defend against phages. Further, we discuss shared mechanisms that pathogens use to overcome host immune pathways and unexpected similarities between bacterial immune systems and interbacterial antagonism. Understanding the shared evolutionary path of immune components across domains of life and the successful strategies that organisms have arrived at to restrict their pathogens will enable future development of therapeutics that activate the human immune system for the precise treatment of disease.
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Affiliation(s)
- Hannah E Ledvina
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Aaron T Whiteley
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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2
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Grandi C, Emmaneel M, Nelissen FHT, Roosenboom LWM, Petrova Y, Elzokla O, Hansen MMK. Decoupled degradation and translation enables noise modulation by poly(A) tails. Cell Syst 2024; 15:526-543.e7. [PMID: 38901403 DOI: 10.1016/j.cels.2024.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 11/24/2023] [Accepted: 05/16/2024] [Indexed: 06/22/2024]
Abstract
Poly(A) tails are crucial for mRNA translation and degradation, but the exact relationship between tail length and mRNA kinetics remains unclear. Here, we employ a small library of identical mRNAs that differ only in their poly(A)-tail length to examine their behavior in human embryonic kidney cells. We find that tail length strongly correlates with mRNA degradation rates but is decoupled from translation. Interestingly, an optimal tail length of ∼100 nt displays the highest translation rate, which is identical to the average endogenous tail length measured by nanopore sequencing. Furthermore, poly(A)-tail length variability-a feature of endogenous mRNAs-impacts translation efficiency but not mRNA degradation rates. Stochastic modeling combined with single-cell tracking reveals that poly(A) tails provide cells with an independent handle to tune gene expression fluctuations by decoupling mRNA degradation and translation. Together, this work contributes to the basic understanding of gene expression regulation and has potential applications in nucleic acid therapeutics.
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Affiliation(s)
- Carmen Grandi
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands; Oncode Institute, Nijmegen, the Netherlands
| | - Martin Emmaneel
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands; Oncode Institute, Nijmegen, the Netherlands
| | - Frank H T Nelissen
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands; Oncode Institute, Nijmegen, the Netherlands
| | - Laura W M Roosenboom
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Yoanna Petrova
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Omnia Elzokla
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Maike M K Hansen
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands; Oncode Institute, Nijmegen, the Netherlands.
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3
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Yu L, Majerciak V, Jia R, Zheng ZM. Revisiting and corrections to the annotated SRSF3 (SRp20) gene structure and RefSeq sequences from the human and mouse genomes. CELL INSIGHT 2023; 2:100089. [PMID: 37193066 PMCID: PMC10134197 DOI: 10.1016/j.cellin.2023.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/14/2023] [Accepted: 02/18/2023] [Indexed: 05/18/2023]
Abstract
SRSF3 (SRp20) is the smallest member of the serine/arginine (SR)-rich protein family. We found the annotated human SRSF3 and mouse Srsf3 RefSeq sequences are much larger than the detected SRSF3/Srsf3 RNA size by Northern blot. Mapping of RNA-seq reads from various human and mouse cell lines to the annotated SRSF3/Srsf3 gene illustrated only a partial coverage of its terminal exon 7. By 5' RACE and 3' RACE, we determined that SRSF3 gene spanning over 8422 bases and Srsf3 gene spanning over 9423 bases. SRSF3/Srsf3 gene has seven exons with exon 7 bearing two alternative polyadenylation signals (PAS). Through alternative PAS selection and exon 4 exclusion/inclusion by alternative RNA splicing, SRSF3/Srsf3 gene expresses four RNA isoforms. The major SRSF3 mRNA isoform with exon 4 exclusion by using a favorable distal PAS to encode a full-length protein is 1411 nt long (not annotated 4228 nt) and the same major mouse Srsf3 mRNA isoform is only 1295 nt (not annotated 2585 nt). The difference from the redefined RNA size of SRSF3/Srsf3 to the corresponding RefSeq sequence is at the 3' UTR region. Collectively, the redefined SRSF3/Srsf3 gene structure and expression will allow better understanding of SRSF3 functions and its regulations in health and diseases.
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Affiliation(s)
- Lulu Yu
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Vladimir Majerciak
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Rong Jia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST), Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
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4
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Rahmati A, Mafi A, Soleymani F, Babaei Aghdam Z, Masihipour N, Ghezelbash B, Asemi R, Aschner M, Vakili O, Homayoonfal M, Asemi Z, Sharifi M, Azadi A, Mirzaei H, Aghadavod E. Circular RNAs: pivotal role in the leukemogenesis and novel indicators for the diagnosis and prognosis of acute myeloid leukemia. Front Oncol 2023; 13:1149187. [PMID: 37124518 PMCID: PMC10140500 DOI: 10.3389/fonc.2023.1149187] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/29/2023] [Indexed: 05/02/2023] Open
Abstract
Acute myeloid leukemia (AML) is an aggressive hematological malignancy and affected patients have poor overall survival (OS) rates. Circular RNAs (circRNAs) are a novel class of non-coding RNAs (ncRNAs) with a unique loop structure. In recent years, with the development of high-throughput RNA sequencing, many circRNAs have been identified exhibiting either up-regulation or down-regulation in AML patients compared with healthy controls. Recent studies have reported that circRNAs regulate leukemia cell proliferation, stemness, and apoptosis, both positively and negatively. Additionally, circRNAs could be promising biomarkers and therapeutic targets in AML. In this study, we present a comprehensive review of the regulatory roles and potentials of a number of dysregulated circRNAs in AML.
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Affiliation(s)
- Atefe Rahmati
- Department of Hematology and Blood Banking, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Basic Sciences, Faculty of Medicine, Neyshabur University of Medical Sciences, Neyshabur, Iran
| | - Alireza Mafi
- Department of Clinical Biochemistry, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Firooze Soleymani
- Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra Babaei Aghdam
- Imaging Sciences Research Group, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Niloufar Masihipour
- Department of Medicine, Lorestan University of Medical Science, Lorestan, Iran
| | - Behrooz Ghezelbash
- Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Reza Asemi
- Department of Internal Medicine, School of Medicine, Cancer Prevention Research Center, Seyyed Al-Shohada Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Omid Vakili
- Department of Clinical Biochemistry, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mina Homayoonfal
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
| | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
| | - Mehran Sharifi
- Department of Internal Medicine, School of Medicine, Cancer Prevention Research Center, Seyyed Al-Shohada Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Abbas Azadi
- Department of Internal Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
- *Correspondence: Abbas Azadi, ; Esmat Aghadavod, ; Hamed Mirzaei, ;
| | - Esmat Aghadavod
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
- Department of Clinical Biochemistry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- *Correspondence: Abbas Azadi, ; Esmat Aghadavod, ; Hamed Mirzaei, ;
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5
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Ielasi FS, Ternifi S, Fontaine E, Iuso D, Couté Y, Palencia A. Human histone pre-mRNA assembles histone or canonical mRNA-processing complexes by overlapping 3'-end sequence elements. Nucleic Acids Res 2022; 50:12425-12443. [PMID: 36447390 PMCID: PMC9756948 DOI: 10.1093/nar/gkac878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 09/20/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Human pre-mRNA processing relies on multi-subunit macromolecular complexes, which recognize specific RNA sequence elements essential for assembly and activity. Canonical pre-mRNA processing proceeds via the recognition of a polyadenylation signal (PAS) and a downstream sequence element (DSE), and produces polyadenylated mature mRNAs, while replication-dependent (RD) histone pre-mRNA processing requires association with a stem-loop (SL) motif and a histone downstream element (HDE), and produces cleaved but non-polyadenylated mature mRNAs. H2AC18 mRNA, a specific H2A RD histone pre-mRNA, can be processed to give either a non-polyadenylated mRNA, ending at the histone SL, or a polyadenylated mRNA. Here, we reveal how H2AC18 captures the two human pre-mRNA processing complexes in a mutually exclusive mode by overlapping a canonical PAS (AAUAAA) sequence element with a HDE. Disruption of the PAS sequence on H2AC18 pre-mRNA prevents recruitment of the canonical complex in vitro, without affecting the histone machinery. This shows how the relative position of cis-acting elements in histone pre-mRNAs allows the selective recruitment of distinct human pre-mRNA complexes, thereby expanding the capability to regulate 3' processing and polyadenylation.
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Affiliation(s)
- Francesco S Ielasi
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Sara Ternifi
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Emeline Fontaine
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Domenico Iuso
- Institute for Advanced Biosciences (IAB), Epigenetics and Cell Signaling, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Andrés Palencia
- To whom correspondence should be addressed. Tel: +33 476 54 95 75;
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6
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Kazzi PE, Rabah N, Chamontin C, Poulain L, Ferron F, Debart F, Canard B, Missé D, Coutard B, Nisole S, Decroly E. Internal RNA 2′O-methylation in the HIV-1 genome counteracts ISG20 nuclease-mediated antiviral effect. Nucleic Acids Res 2022; 51:2501-2515. [PMID: 36354007 PMCID: PMC10085690 DOI: 10.1093/nar/gkac996] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 09/16/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
Abstract
RNA 2′O-methylation is a ‘self’ epitranscriptomic modification allowing discrimination between host and pathogen. Indeed, human immunodeficiency virus 1 (HIV-1) induces 2′O-methylation of its genome by recruiting the cellular FTSJ3 methyltransferase, thereby impairing detection by RIG-like receptors. Here, we show that RNA 2′O-methylations interfere with the antiviral activity of interferon-stimulated gene 20-kDa protein (ISG20). Biochemical experiments showed that ISG20-mediated degradation of 2′O-methylated RNA pauses two nucleotides upstream of and at the methylated residue. Structure-function analysis indicated that this inhibition is due to steric clash between ISG20 R53 and D90 residues and the 2′O-methylated nucleotide. We confirmed that hypomethylated HIV-1 genomes produced in FTSJ3-KO cells were more prone to in vitro degradation by ISG20 than those produced in cells expressing FTSJ3. Finally, we found that reverse-transcription of hypomethylated HIV-1 was impaired in T cells by interferon-induced ISG20, demonstrating the direct antagonist effect of 2′O-methylation on ISG20-mediated antiviral activity.
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Affiliation(s)
- Priscila El Kazzi
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
| | - Nadia Rabah
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
- Université de Toulon , 83130 La Garde , France
| | - Célia Chamontin
- IRIM, CNRS UMR9004, Université de Montpellier , Montpellier , France
| | - Lina Poulain
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
| | - François Ferron
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
- European Virus Bioinformatics Center , Leutragraben 1, 07743 Jena , Germany
| | - Françoise Debart
- IBMM, UMR 5247 CNRS, Université de Montpellier , ENSCM, Montpellier , France
| | - Bruno Canard
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
| | - Dorothée Missé
- MIVEGEC, Univ. Montpellier, CNRS , IRD, Montpellier, France
| | - Bruno Coutard
- Unité des Virus Émergents (UVE: Aix-Marseille Univ-IRD 190-Inserm 1207) , Marseille , France
| | - Sébastien Nisole
- IRIM, CNRS UMR9004, Université de Montpellier , Montpellier , France
| | - Etienne Decroly
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
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7
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Klama S, Hirsch AG, Schneider UM, Zander G, Seel A, Krebber H. A guard protein mediated quality control mechanism monitors 5'-capping of pre-mRNAs. Nucleic Acids Res 2022; 50:11301-11314. [PMID: 36305816 PMCID: PMC9638935 DOI: 10.1093/nar/gkac952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 09/30/2022] [Accepted: 10/12/2022] [Indexed: 07/26/2023] Open
Abstract
Efficient gene expression requires properly matured mRNAs for functional transcript translation. Several factors including the guard proteins monitor maturation and act as nuclear retention factors for unprocessed pre-mRNAs. Here we show that the guard protein Npl3 monitors 5'-capping. In its absence, uncapped transcripts resist degradation, because the Rat1-Rai1 5'-end degradation factors are not efficiently recruited to these faulty transcripts. Importantly, in npl3Δ, these improperly capped transcripts escape this quality control checkpoint and leak into the cytoplasm. Our data suggest a model in which Npl3 associates with the Rai1 bound pre-mRNAs. In case the transcript was properly capped and is thus CBC (cap binding complex) bound, Rai1 dissociates from Npl3 allowing the export factor Mex67 to interact with this guard protein and support nuclear export. In case Npl3 does not detect proper capping through CBC attachment, Rai1 binding persists and Rat1 can join this 5'-complex to degrade the faulty transcript.
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Affiliation(s)
| | | | - Ulla M Schneider
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen 37077, Germany
| | - Gesa Zander
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen 37077, Germany
| | - Anika Seel
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen 37077, Germany
| | - Heike Krebber
- To whom correspondence should be addressed. Tel: +49 551 39 33801; Fax: +49 551 39 33805;
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Yu L, Majerciak V, Zheng ZM. HPV16 and HPV18 Genome Structure, Expression, and Post-Transcriptional Regulation. Int J Mol Sci 2022; 23:ijms23094943. [PMID: 35563334 PMCID: PMC9105396 DOI: 10.3390/ijms23094943] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 12/18/2022] Open
Abstract
Human papillomaviruses (HPV) are a group of small non-enveloped DNA viruses whose infection causes benign tumors or cancers. HPV16 and HPV18, the two most common high-risk HPVs, are responsible for ~70% of all HPV-related cervical cancers and head and neck cancers. The expression of the HPV genome is highly dependent on cell differentiation and is strictly regulated at the transcriptional and post-transcriptional levels. Both HPV early and late transcripts differentially expressed in the infected cells are intron-containing bicistronic or polycistronic RNAs bearing more than one open reading frame (ORF), because of usage of alternative viral promoters and two alternative viral RNA polyadenylation signals. Papillomaviruses proficiently engage alternative RNA splicing to express individual ORFs from the bicistronic or polycistronic RNA transcripts. In this review, we discuss the genome structures and the updated transcription maps of HPV16 and HPV18, and the latest research advances in understanding RNA cis-elements, intron branch point sequences, and RNA-binding proteins in the regulation of viral RNA processing. Moreover, we briefly discuss the epigenetic modifications, including DNA methylation and possible APOBEC-mediated genome editing in HPV infections and carcinogenesis.
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9
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Architectural and functional details of CF IA proteins involved in yeast 3'-end pre-mRNA processing and its significance for eukaryotes: A concise review. Int J Biol Macromol 2021; 193:387-400. [PMID: 34699898 DOI: 10.1016/j.ijbiomac.2021.10.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/04/2021] [Accepted: 10/18/2021] [Indexed: 11/22/2022]
Abstract
In eukaryotes, maturation of pre-mRNA relies on its precise 3'-end processing. This processing involves co-transcriptional steps regulated by sequence elements and other proteins. Although, it holds tremendous importance, defect in the processing machinery will result in erroneous pre-mRNA maturation leading to defective translation. Remarkably, more than 20 proteins in humans and yeast share homology and execute this processing. The defects in this processing are associated with various diseases in humans. We shed light on the CF IA subunit of yeast Saccharomyces cerevisiae that contains four proteins (Pcf11, Clp1, Rna14 and Rna15) involved in this processing. Structural details of various domains of CF IA and their roles during 3'-end processing, like cleavage and polyadenylation at 3'-UTR of pre-mRNA and other cellular events are explained. Further, the chronological development and important discoveries associated with 3'-end processing are summarized. Moreover, the mammalian homologues of yeast CF IA proteins, along with their key roles are described. This knowledge would be helpful for better comprehension of the mechanism associated with this marvel; thus opening up vast avenues in this area.
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Agostini F, Zagalak J, Attig J, Ule J, Luscombe NM. Intergenic RNA mainly derives from nascent transcripts of known genes. Genome Biol 2021; 22:136. [PMID: 33952325 PMCID: PMC8097831 DOI: 10.1186/s13059-021-02350-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/12/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Eukaryotic genomes undergo pervasive transcription, leading to the production of many types of stable and unstable RNAs. Transcription is not restricted to regions with annotated gene features but includes almost any genomic context. Currently, the source and function of most RNAs originating from intergenic regions in the human genome remain unclear. RESULTS We hypothesize that many intergenic RNAs can be ascribed to the presence of as-yet unannotated genes or the "fuzzy" transcription of known genes that extends beyond the annotated boundaries. To elucidate the contributions of these two sources, we assemble a dataset of more than 2.5 billion publicly available RNA-seq reads across 5 human cell lines and multiple cellular compartments to annotate transcriptional units in the human genome. About 80% of transcripts from unannotated intergenic regions can be attributed to the fuzzy transcription of existing genes; the remaining transcripts originate mainly from putative long non-coding RNA loci that are rarely spliced. We validate the transcriptional activity of these intergenic RNAs using independent measurements, including transcriptional start sites, chromatin signatures, and genomic occupancies of RNA polymerase II in various phosphorylation states. We also analyze the nuclear localization and sensitivities of intergenic transcripts to nucleases to illustrate that they tend to be rapidly degraded either on-chromatin by XRN2 or off-chromatin by the exosome. CONCLUSIONS We provide a curated atlas of intergenic RNAs that distinguishes between alternative processing of well-annotated genes from independent transcriptional units based on the combined analysis of chromatin signatures, nuclear RNA localization, and degradation pathways.
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Affiliation(s)
| | - Julian Zagalak
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jan Attig
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Jernej Ule
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Nicholas M Luscombe
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- UCL Genetics Institute, Department of Genetics, Environment and Evolution, University College London, Gower Street, London, WC1E 6BT, UK
- Okinawa Institute of Science & Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
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11
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Interplay of mRNA capping and transcription machineries. Biosci Rep 2021; 40:221784. [PMID: 31904821 PMCID: PMC6981093 DOI: 10.1042/bsr20192825] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/02/2020] [Accepted: 01/06/2020] [Indexed: 12/31/2022] Open
Abstract
Early stages of transcription from eukaryotic promoters include two principal events: the capping of newly synthesized mRNA and the transition of RNA polymerase II from the preinitiation complex to the productive elongation state. The capping checkpoint model implies that these events are tightly coupled, which is necessary for ensuring the proper capping of newly synthesized mRNA. Recent findings also show that the capping machinery has a wider effect on transcription and the entire gene expression process. The molecular basis of these phenomena is discussed.
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12
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Pan S, Li KE, Huang W, Zhong H, Wu H, Wang Y, Zhang H, Cai Z, Guo H, Chen X, Xia Y. Arabidopsis DXO1 possesses deNADding and exonuclease activities and its mutation affects defense-related and photosynthetic gene expression. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:967-983. [PMID: 31449356 PMCID: PMC8034840 DOI: 10.1111/jipb.12867] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/23/2019] [Indexed: 05/26/2023]
Abstract
RNA capping and decapping tightly coordinate with transcription, translation, and RNA decay to regulate gene expression. Proteins in the DXO/Rai1 family have been implicated in mRNA decapping and decay, and mammalian DXO was recently found to also function as a decapping enzyme for NAD+ -capped RNAs (NAD-RNA). The Arabidopsis genome contains a single gene encoding a DXO/Rai1 protein, AtDXO1. Here we show that AtDXO1 possesses both NAD-RNA decapping activity and 5'-3' exonuclease activity but does not hydrolyze the m7 G cap. The atdxo1 mutation increased the stability of NAD-RNAs and led to pleiotropic phenotypes, including severe growth retardation, pale color, and multiple developmental defects. Transcriptome profiling analysis showed that the atdxo1 mutation resulted in upregulation of defense-related genes but downregulation of photosynthesis-related genes. The autoimmunity phenotype of the mutant could be suppressed by either eds1 or npr1 mutation. However, the various phenotypes associated with the atdxo1 mutant could be complemented by an enzymatically inactive AtDXO1. The atdxo1 mutation apparently enhances post-transcriptional gene silencing by elevating levels of siRNAs. Our study indicates that AtDXO1 regulates gene expression in various biological and physiological processes through its pleiotropic molecular functions in mediating RNA processing and decay.
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Affiliation(s)
- Shuying Pan
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Kai-en Li
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Wei Huang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Huan Zhong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Huihui Wu
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuan Wang
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, California 92521, USA
| | - He Zhang
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Hongwei Guo
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, California 92521, USA
| | - Yiji Xia
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
- State Key Laboratory of Agricultural Biotechnology, School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
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13
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Zhou ZD, Selvaratnam T, Lee JCT, Chao YX, Tan EK. Molecular targets for modulating the protein translation vital to proteostasis and neuron degeneration in Parkinson's disease. Transl Neurodegener 2019; 8:6. [PMID: 30740222 PMCID: PMC6360798 DOI: 10.1186/s40035-019-0145-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/14/2019] [Indexed: 12/13/2022] Open
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder, which is characterized by the progressive loss of dopaminergic neurons in the Substantia Nigra pars compacta concomitant with Lewy body formation in affected brain areas. The detailed pathogenic mechanisms underlying the selective loss of dopaminergic neurons in PD are unclear, and no drugs or treatments have been developed to alleviate progressive dopaminergic neuron degeneration in PD. However, the formation of α-synuclein-positive protein aggregates in Lewy body has been identified as a common pathological feature of PD, possibly stemming from the consequence of protein misfolding and dysfunctional proteostasis. Proteostasis is the mechanism for maintaining protein homeostasis via modulation of protein translation, enhancement of chaperone capacity and the prompt clearance of misfolded protein by the ubiquitin proteasome system and autophagy. Deregulated protein translation and impaired capacities of chaperone or protein degradation can disturb proteostasis processes, leading to pathological protein aggregation and neurodegeneration in PD. In recent years, multiple molecular targets in the modulation of protein translation vital to proteostasis and dopaminergic neuron degeneration have been identified. The potential pathophysiological and therapeutic significance of these molecular targets to neurodegeneration in PD is highlighted.
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Affiliation(s)
- Zhi Dong Zhou
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
- Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Medical School Singapore, 8 College Road, Singapore, Singapore
| | - Thevapriya Selvaratnam
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Ji Chao Tristan Lee
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Yin Xia Chao
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Eng-King Tan
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
- Department of Neurology, Singapore General Hospital, Outram Road, Singapore, 169608 Singapore
- Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Medical School Singapore, 8 College Road, Singapore, Singapore
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14
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Kramer S, McLennan AG. The complex enzymology of mRNA decapping: Enzymes of four classes cleave pyrophosphate bonds. WILEY INTERDISCIPLINARY REVIEWS. RNA 2019; 10:e1511. [PMID: 30345629 DOI: 10.1002/wrna.1511] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 12/16/2022]
Abstract
The 5' ends of most RNAs are chemically modified to enable protection from nucleases. In bacteria, this is often achieved by keeping the triphosphate terminus originating from transcriptional initiation, while most eukaryotic mRNAs and small nuclear RNAs have a 5'→5' linked N7 -methyl guanosine (m7 G) cap added. Several other chemical modifications have been described at RNA 5' ends. Common to all modifications is the presence of at least one pyrophosphate bond. To enable RNA turnover, these chemical modifications at the RNA 5' end need to be reversible. Dependent on the direction of the RNA decay pathway (5'→3' or 3'→5'), some enzymes cleave the 5'→5' cap linkage of intact RNAs to initiate decay, while others act as scavengers and hydrolyse the cap element of the remnants of the 3'→5' decay pathway. In eukaryotes, there is also a cap quality control pathway. Most enzymes involved in the cleavage of the RNA 5' ends are pyrophosphohydrolases, with only a few having (additional) 5' triphosphonucleotide hydrolase activities. Despite the identity of their enzyme activities, the enzymes belong to four different enzyme classes. Nudix hydrolases decap intact RNAs as part of the 5'→3' decay pathway, DXO family members mainly degrade faulty RNAs, members of the histidine triad (HIT) family are scavenger proteins, while an ApaH-like phosphatase is the major mRNA decay enzyme of trypanosomes, whose RNAs have a unique cap structure. Many novel cap structures and decapping enzymes have only recently been discovered, indicating that we are only beginning to understand the mechanisms of RNA decapping. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Turnover and Surveillance > Regulation of RNA Stability RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Susanne Kramer
- Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Alexander G McLennan
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
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15
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Zarudnaya MI, Kolomiets IM, Potyahaylo AL, Hovorun DM. Structural transitions in poly(A), poly(C), poly(U), and poly(G) and their possible biological roles. J Biomol Struct Dyn 2018; 37:2837-2866. [PMID: 30052138 DOI: 10.1080/07391102.2018.1503972] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The homopolynucleotide (homo-oligonucleotide) tracts function as regulatory elements at various stages of mRNAs life cycle. Numerous cellular proteins specifically bind to these tracts. Among them are the different poly(A)-binding proteins, poly(C)-binding proteins, multifunctional fragile X mental retardation protein which binds specifically both to poly(G) and poly(U) and others. Molecular mechanisms of regulation of gene expression mediated by homopolynucleotide tracts in RNAs are not fully understood and the structural diversity of these tracts can contribute substantially to this regulation. This review summarizes current knowledge on different forms of homoribopolynucleotides, in particular, neutral and acidic forms of poly(A) and poly(C), and also biological relevance of homoribopolynucleotide (homoribo-oligonucleotide) tracts is discussed. Under physiological conditions, the acidic forms of poly(A) and poly(C) can be induced by proton transfer from acidic amino acids of proteins to adenine and cytosine bases. Finally, we present potential mechanisms for the regulation of some biological processes through the formation of intramolecular poly(A) duplexes.
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Affiliation(s)
- Margarita I Zarudnaya
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Iryna M Kolomiets
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Andriy L Potyahaylo
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Dmytro M Hovorun
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine.,b Department of Molecular Biotechnology and Bioinformatics , Institute of High Technologies, Taras Shevchenko National University of Kyiv , Kyiv , Ukraine
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16
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Yun JS, Yoon JH, Choi YJ, Son YJ, Kim S, Tong L, Chang JH. Molecular mechanism for the inhibition of DXO by adenosine 3',5'-bisphosphate. Biochem Biophys Res Commun 2018; 504:89-95. [PMID: 30180947 DOI: 10.1016/j.bbrc.2018.08.135] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/22/2018] [Indexed: 10/28/2022]
Abstract
The decapping exoribonuclease DXO functions in pre-mRNA capping quality control, and shows multiple biochemical activities such as decapping, deNADding, pyrophosphohydrolase, and 5'-3' exoribonuclease activities. Previous studies revealed the molecular mechanisms of DXO based on the structures in complexes with a product, substrate mimic, cap analogue, and 3'-NADP+. Despite several reports on the substrate-specific reaction mechanism, the inhibitory mechanism of DXO remains elusive. Here, we demonstrate that adenosine 3', 5'-bisphosphate (pAp), a known inhibitor of the 5'-3' exoribonuclease Xrn1, inhibits the nuclease activity of DXO based on the results of structural and biochemical experiments. We determined the crystal structure of the DXO-pAp-Mg2+ complex at 1.8 Å resolution. In comparison with the DXO-RNA product complex, the position of pAp is well superimposed with the first nucleotide of the product RNA in the vicinity of two magnesium ions. Furthermore, biochemical assays showed that the inhibition by pAp is comparable between Xrn1 and DXO. Collectively, these structural and biochemical studies reveal that pAp inhibits the activities of DXO by occupying the active site to act as a competitive inhibitor.
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Affiliation(s)
- Ji-Sook Yun
- Department of Biology Education, Kyungpook National University, Daegu 41566, South Korea
| | - Je-Hyun Yoon
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Young Jun Choi
- Department of Biology Education, Kyungpook National University, Daegu 41566, South Korea
| | - Young Jin Son
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, South Korea
| | - Sunghwan Kim
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, South Korea
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - Jeong Ho Chang
- Department of Biology Education, Kyungpook National University, Daegu 41566, South Korea; Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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17
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Kiledjian M. Eukaryotic RNA 5'-End NAD + Capping and DeNADding. Trends Cell Biol 2018; 28:454-464. [PMID: 29544676 PMCID: PMC5962413 DOI: 10.1016/j.tcb.2018.02.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/30/2018] [Accepted: 02/15/2018] [Indexed: 12/28/2022]
Abstract
A hallmark of eukaryotic mRNAs has long been the 5'-end m7G cap. This paradigm was recently amended by recent reports that Saccharomyces cerevisiae and mammalian cells also contain mRNAs carrying a novel nicotinamide adenine dinucleotide (NAD+) cap at their 5'-end. The presence of an NAD+ cap on mRNA uncovers a previously unknown mechanism for controlling gene expression through nucleotide metabolite-directed mRNA turnover. In contrast to the m7G cap that stabilizes mRNA, the NAD+ cap targets RNA for rapid decay in mammalian cells through the DXO non-canonical decapping enzyme which removes intact NAD+ from RNA in a process termed 'deNADding'. This review highlights the identification of NAD+ caps, their mode of addition, and their functional significance in cells.
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Affiliation(s)
- Megerditch Kiledjian
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA.
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18
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Eger N, Schoppe L, Schuster S, Laufs U, Boeckel JN. Circular RNA Splicing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1087:41-52. [PMID: 30259356 DOI: 10.1007/978-981-13-1426-1_4] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Circular RNAs (circRNAs) are covalently closed single-stranded RNA molecules derived from exons by alternative mRNA splicing. Circularization of single-stranded RNA molecules was already described in 1976 for viroids in plants. Since then several additional types of circular RNAs in many species have been described such as the circular single-stranded RNA genome of the hepatitis delta virus (HDV) or circular RNAs as products or intermediates of tRNA and rRNA maturation in archaea. CircRNAs are generally formed by covalent binding of the 5' site of an upstream exon with the 3' of the same or a downstream exon. Meanwhile, two different models of circRNA biogenesis have been described, the lariat or exon skipping model and the direct backsplicing model. In the lariat model, canonical splicing occurs before backsplicing, whereas in the direct backsplicing model, the circRNA is generated first. In this chapter, we will review the formation of circular RNAs and highlight the derivation of different types of circular RNAs.
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Affiliation(s)
- Nicole Eger
- University of Heidelberg, Heidelberg, Germany
| | | | - Susanne Schuster
- Clinic and Polyclinic for Cardiology, University Hospital Leipzig, Leipzig, Germany
| | - Ulrich Laufs
- Clinic and Polyclinic for Cardiology, University Hospital Leipzig, Leipzig, Germany
| | - Jes-Niels Boeckel
- Clinic and Polyclinic for Cardiology, University Hospital Leipzig, Leipzig, Germany.
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19
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Martins RP, Fåhraeus R. A matter of maturity: The impact of pre-mRNA processing in gene expression and antigen presentation. Int J Biochem Cell Biol 2017; 91:203-211. [PMID: 28549625 DOI: 10.1016/j.biocel.2017.05.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/15/2017] [Accepted: 05/18/2017] [Indexed: 12/28/2022]
Abstract
RNA processing plays a pivotal role in the diversification of high eukaryotes transcriptome and proteome. The expression of gene products controlling a variety of cellular and physiological processes depends largely on a complex maturation process undergone by pre-mRNAs to become translation-competent mRNAs. Here we review the different mechanisms involved in the pre-mRNA processing and disclose their impact in the gene regulation process in eukaryotic cells. We describe some viral strategies targeting pre-mRNA processing to control gene expression and host immune response and discuss their relevance as tools for a better understanding of cell biology. Finally, we highlight accumulating evidences toward the occurrence of a translation event coupled to mRNA biogenesis in the nuclear compartment and argue how this is relevant for the production of antigenic peptide substrates for the major histocompatibility complex class I pathway.
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Affiliation(s)
- Rodrigo Prado Martins
- Équipe Labellisée Ligue Contre le Cancer, Université Paris 7, INSERM UMR 1162, 27 rue Juliette Dodu, 75010 Paris, France.
| | - Robin Fåhraeus
- Équipe Labellisée Ligue Contre le Cancer, Université Paris 7, INSERM UMR 1162, 27 rue Juliette Dodu, 75010 Paris, France; Department of Medical Biosciences, Umeå University, Umeå, Sweden; RECAMO, Masaryk Memorial Cancer Institute, Brno, Czech Republic
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20
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Molecular basis for the interaction between Integrator subunits IntS9 and IntS11 and its functional importance. Proc Natl Acad Sci U S A 2017; 114:4394-4399. [PMID: 28396433 DOI: 10.1073/pnas.1616605114] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The metazoan Integrator complex (INT) has important functions in the 3'-end processing of noncoding RNAs, including the uridine-rich small nuclear RNA (UsnRNA) and enhancer RNA (eRNA), and in the transcription of coding genes by RNA polymerase II. The INT contains at least 14 subunits, but its molecular mechanism of action is poorly understood, because currently there is little structural information about its subunits. The endonuclease activity of INT is mediated by its subunit 11 (IntS11), which belongs to the metallo-β-lactamase superfamily and is a paralog of CPSF-73, the endonuclease for pre-mRNA 3'-end processing. IntS11 forms a stable complex with Integrator complex subunit 9 (IntS9) through their C-terminal domains (CTDs). Here, we report the crystal structure of the IntS9-IntS11 CTD complex at 2.1-Å resolution and detailed, structure-based biochemical and functional studies. The complex is composed of a continuous nine-stranded β-sheet with four strands from IntS9 and five from IntS11. Highly conserved residues are located in the extensive interface between the two CTDs. Yeast two-hybrid assays and coimmunoprecipitation experiments confirm the structural observations on the complex. Functional studies demonstrate that the IntS9-IntS11 interaction is crucial for the role of INT in snRNA 3'-end processing.
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21
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Zhang Y, Rataj K, Simpson GG, Tong L. Crystal Structure of the SPOC Domain of the Arabidopsis Flowering Regulator FPA. PLoS One 2016; 11:e0160694. [PMID: 27513867 PMCID: PMC4981400 DOI: 10.1371/journal.pone.0160694] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/23/2016] [Indexed: 11/18/2022] Open
Abstract
The Arabidopsis protein FPA controls flowering time by regulating the alternative 3′-end processing of the FLOWERING LOCUS (FLC) antisense RNA. FPA belongs to the split ends (SPEN) family of proteins, which contain N-terminal RNA recognition motifs (RRMs) and a SPEN paralog and ortholog C-terminal (SPOC) domain. The SPOC domain is highly conserved among FPA homologs in plants, but the conservation with the domain in other SPEN proteins is much lower. We have determined the crystal structure of Arabidopsis thaliana FPA SPOC domain at 2.7 Å resolution. The overall structure is similar to that of the SPOC domain in human SMRT/HDAC1 Associated Repressor Protein (SHARP), although there are also substantial conformational differences between them. Structural and sequence analyses identify a surface patch that is conserved among plant FPA homologs. Mutations of two residues in this surface patch did not disrupt FPA functions, suggesting that either the SPOC domain is not required for the role of FPA in regulating RNA 3′-end formation or the functions of the FPA SPOC domain cannot be disrupted by the combination of mutations, in contrast to observations with the SHARP SPOC domain.
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Affiliation(s)
- Yinglu Zhang
- Department of Biological Sciences, Columbia University, New York, NY, 10027, United States of America
| | - Katarzyna Rataj
- Division Plant Sciences & Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, United Kingdom
| | - Gordon G. Simpson
- Division Plant Sciences & Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, United Kingdom
- Cell & Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, Scotland, United Kingdom
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, 10027, United States of America
- * E-mail:
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22
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Grudzien-Nogalska E, Kiledjian M. New insights into decapping enzymes and selective mRNA decay. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27425147 DOI: 10.1002/wrna.1379] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/23/2016] [Accepted: 06/27/2016] [Indexed: 01/04/2023]
Abstract
Removal of the 5' end cap is a critical determinant controlling mRNA stability and efficient gene expression. Removal of the cap is exquisitely controlled by multiple direct and indirect regulators that influence association with the cap and the catalytic step. A subset of these factors directly stimulate activity of the decapping enzyme, while others influence remodeling of factors bound to mRNA and indirectly stimulate decapping. Furthermore, the components of the general decapping machinery can also be recruited by mRNA-specific regulatory proteins to activate decapping. The Nudix hydrolase, Dcp2, identified as a first decapping enzyme, cleaves capped mRNA and initiates 5'-3' degradation. Extensive studies on Dcp2 led to broad understanding of its activity and the regulation of transcript specific decapping and decay. Interestingly, seven additional Nudix proteins possess intrinsic decapping activity in vitro and at least two, Nudt16 and Nudt3, are decapping enzymes that regulate mRNA stability in cells. Furthermore, a new class of decapping proteins within the DXO family preferentially function on incompletely capped mRNAs. Importantly, it is now evident that each of the characterized decapping enzymes predominantly modulates only a subset of mRNAs, suggesting the existence of multiple decapping enzymes functioning in distinct cellular pathways. WIREs RNA 2017, 8:e1379. doi: 10.1002/wrna.1379 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ewa Grudzien-Nogalska
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Megerditch Kiledjian
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
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23
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Ziemniak M, Mugridge JS, Kowalska J, Rhoads RE, Gross JD, Jemielity J. Two-headed tetraphosphate cap analogs are inhibitors of the Dcp1/2 RNA decapping complex. RNA (NEW YORK, N.Y.) 2016; 22:518-29. [PMID: 26826132 PMCID: PMC4793208 DOI: 10.1261/rna.055152.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/10/2015] [Indexed: 05/08/2023]
Abstract
Dcp1/2 is the major eukaryotic RNA decapping complex, comprised of the enzyme Dcp2 and activator Dcp1, which removes the 5' m(7)G cap from mRNA, committing the transcript to degradation. Dcp1/2 activity is crucial for RNA quality control and turnover, and deregulation of these processes may lead to disease development. The molecular details of Dcp1/2 catalysis remain elusive, in part because both cap substrate (m(7)GpppN) and m(7)GDP product are bound by Dcp1/2 with weak (mM) affinity. In order to find inhibitors to use in elucidating the catalytic mechanism of Dcp2, we screened a small library of synthetic m(7)G nucleotides (cap analogs) bearing modifications in the oligophosphate chain. One of the most potent cap analogs, m(7)GpSpppSm(7)G, inhibited Dcp1/2 20 times more efficiently than m(7)GpppN or m(7)GDP. NMR experiments revealed that the compound interacts with specific surfaces of both regulatory and catalytic domains of Dcp2 with submillimolar affinities. Kinetics analysis revealed that m(7)GpSpppSm(7)G is a mixed inhibitor that competes for the Dcp2 active site with micromolar affinity. m(7)GpSpppSm(7)G-capped RNA undergoes rapid decapping, suggesting that the compound may act as a tightly bound cap mimic. Our identification of the first small molecule inhibitor of Dcp2 should be instrumental in future studies aimed at understanding the structural basis of RNA decapping and may provide insight toward the development of novel therapeutically relevant decapping inhibitors.
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Affiliation(s)
- Marcin Ziemniak
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Jeffrey S Mugridge
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, USA
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Robert E Rhoads
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-3932, USA
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, USA
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
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24
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Li Z, Jiang D, Fu X, Luo X, Liu R, He Y. Coupling of histone methylation and RNA processing by the nuclear mRNA cap-binding complex. NATURE PLANTS 2016; 2:16015. [PMID: 27249350 DOI: 10.1038/nplants.2016.15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 01/14/2016] [Indexed: 05/08/2023]
Abstract
In eukaryotes, genes are transcribed into pre-mRNAs that are subsequently processed into mature mRNAs by adding a 5'-cap and a 3'-polyA tail and splicing introns. Pre-mRNA processing involves their binding proteins and processing factors, whereas gene transcription often involves chromatin modifiers. It has been unclear how the factors involved in chromatin modifications and RNA processing function in concert to control mRNA production. Here, we show that in Arabidopsis thaliana, the evolutionarily conserved nuclear mRNA cap-binding complex (CBC) forms multi-protein complexes with a conserved histone 3 lysine 4 (H3K4) methyltransferase complex called COMPASS-like and a histone 3 lysine 36 (H3K36) methyltransferase to integrate active histone methylations with co-transcriptional mRNA processing and cap preservation, leading to a high level of mature mRNA production. We further show that CBC is required for H3K4 and H3K36 trimethylation, and the histone methyltransferases are required for CBC-mediated mRNA cap preservation and efficient pre-mRNA splicing at their target loci, suggesting that these factors are functionally interdependent. Our study reveals novel roles for histone methyltransferases in RNA-processing-related events and provides mechanistic insights into how the 'downstream' RNA CBC controls eukaryotic gene transcription.
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Affiliation(s)
- Zicong Li
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543 Singapore, Singapore
| | - Danhua Jiang
- Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543 Singapore, Singapore
| | - Xing Fu
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Xiao Luo
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Renyi Liu
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Yuehui He
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543 Singapore, Singapore
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25
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Wang VYF, Jiao X, Kiledjian M, Tong L. Structural and biochemical studies of the distinct activity profiles of Rai1 enzymes. Nucleic Acids Res 2015; 43:6596-606. [PMID: 26101253 PMCID: PMC4513879 DOI: 10.1093/nar/gkv620] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 06/02/2015] [Indexed: 11/14/2022] Open
Abstract
Recent studies showed that Rai1 and its homologs are a crucial component of the mRNA 5'-end capping quality control mechanism. They can possess RNA 5'-end pyrophosphohydrolase (PPH), decapping, and 5'-3' exonuclease (toward 5' monophosphate RNA) activities, which help to degrade mRNAs with incomplete 5'-end capping. A single active site in the enzyme supports these apparently distinct activities. However, each Rai1 protein studied so far has a unique set of activities, and the molecular basis for these differences are not known. Here, we have characterized the highly diverse activity profiles of Rai1 homologs from a collection of fungal organisms and identified a new activity for these enzymes, 5'-end triphosphonucleotide hydrolase (TPH) instead of PPH activity. Crystal structures of two of these enzymes bound to RNA oligonucleotides reveal differences in the RNA binding modes. Structure-based mutations of these enzymes, changing residues that contact the RNA but are poorly conserved, have substantial effects on their activity, providing a framework to begin to understand the molecular basis for the different activity profiles.
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Affiliation(s)
- Vivien Ya-Fan Wang
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Xinfu Jiao
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Megerditch Kiledjian
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Walsh MJ, Cooper-Knock J, Dodd JE, Stopford MJ, Mihaylov SR, Kirby J, Shaw PJ, Hautbergue GM. Invited review: decoding the pathophysiological mechanisms that underlie RNA dysregulation in neurodegenerative disorders: a review of the current state of the art. Neuropathol Appl Neurobiol 2015; 41:109-34. [PMID: 25319671 PMCID: PMC4329338 DOI: 10.1111/nan.12187] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/07/2014] [Indexed: 12/12/2022]
Abstract
Altered RNA metabolism is a key pathophysiological component causing several neurodegenerative diseases. Genetic mutations causing neurodegeneration occur in coding and noncoding regions of seemingly unrelated genes whose products do not always contribute to the gene expression process. Several pathogenic mechanisms may coexist within a single neuronal cell, including RNA/protein toxic gain-of-function and/or protein loss-of-function. Genetic mutations that cause neurodegenerative disorders disrupt healthy gene expression at diverse levels, from chromatin remodelling, transcription, splicing, through to axonal transport and repeat-associated non-ATG (RAN) translation. We address neurodegeneration in repeat expansion disorders [Huntington's disease, spinocerebellar ataxias, C9ORF72-related amyotrophic lateral sclerosis (ALS)] and in diseases caused by deletions or point mutations (spinal muscular atrophy, most subtypes of familial ALS). Some neurodegenerative disorders exhibit broad dysregulation of gene expression with the synthesis of hundreds to thousands of abnormal messenger RNA (mRNA) molecules. However, the number and identity of aberrant mRNAs that are translated into proteins - and how these lead to neurodegeneration - remain unknown. The field of RNA biology research faces the challenge of identifying pathophysiological events of dysregulated gene expression. In conclusion, we discuss current research limitations and future directions to improve our characterization of pathological mechanisms that trigger disease onset and progression.
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Affiliation(s)
- M J Walsh
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J Cooper-Knock
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J E Dodd
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - M J Stopford
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - S R Mihaylov
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J Kirby
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - P J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - G M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
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Brocato J, Fang L, Chervona Y, Chen D, Kiok K, Sun H, Tseng HC, Xu D, Shamy M, Jin C, Costa M. Arsenic induces polyadenylation of canonical histone mRNA by down-regulating stem-loop-binding protein gene expression. J Biol Chem 2014; 289:31751-31764. [PMID: 25266719 DOI: 10.1074/jbc.m114.591883] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The replication-dependent histone genes are the only metazoan genes whose messenger RNA (mRNA) does not terminate with a poly(A) tail at the 3'-end. Instead, the histone mRNAs display a stem-loop structure at their 3'-end. Stem-loop-binding protein (SLBP) binds the stem-loop and regulates canonical histone mRNA metabolism. Here we report that exposure to arsenic, a carcinogenic metal, decreased cellular levels of SLBP by inducing its proteasomal degradation and inhibiting SLBP transcription via epigenetic mechanisms. Notably, arsenic exposure dramatically increased polyadenylation of canonical histone H3.1 mRNA possibly through down-regulation of SLBP expression. The polyadenylated H3.1 mRNA induced by arsenic was not susceptible to normal degradation that occurs at the end of S phase, resulting in continued presence into mitosis, increased total H3.1 mRNA, and increased H3 protein levels. Excess expression of canonical histones have been shown to increase sensitivity to DNA damage as well as increase the frequency of missing chromosomes and induce genomic instability. Thus, polyadenylation of canonical histone mRNA following arsenic exposure may contribute to arsenic-induced carcinogenesis.
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Affiliation(s)
- Jason Brocato
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Lei Fang
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Yana Chervona
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Danqi Chen
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Kathrin Kiok
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Hong Sun
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Hsiang-Chi Tseng
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Dazhong Xu
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
| | - Magdy Shamy
- Department of Environmental Sciences, Faculty of Meteorology, Environment, and Arid Land Agriculture, King Abdulaziz University, Jeddah 21432, Saudi Arabia
| | - Chunyuan Jin
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and.
| | - Max Costa
- Department of Environmental Medicine, New York University School of Medicine, New York, New York 10016 and
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