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Heimdörfer D, Vorleuter A, Eschlböck A, Spathopoulou A, Suarez-Cubero M, Farhan H, Reiterer V, Spanjaard M, Schaaf CP, Huber LA, Kremser L, Sarg B, Edenhofer F, Geley S, de Araujo MEG, Huettenhofer A. Truncated variants of MAGEL2 are involved in the etiologies of the Schaaf-Yang and Prader-Willi syndromes. Am J Hum Genet 2024; 111:1383-1404. [PMID: 38908375 PMCID: PMC11267527 DOI: 10.1016/j.ajhg.2024.05.023] [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: 04/16/2024] [Revised: 05/27/2024] [Accepted: 05/29/2024] [Indexed: 06/24/2024] Open
Abstract
The neurodevelopmental disorders Prader-Willi syndrome (PWS) and Schaaf-Yang syndrome (SYS) both arise from genomic alterations within human chromosome 15q11-q13. A deletion of the SNORD116 cluster, encoding small nucleolar RNAs, or frameshift mutations within MAGEL2 result in closely related phenotypes in individuals with PWS or SYS, respectively. By investigation of their subcellular localization, we observed that in contrast to a predominant cytoplasmic localization of wild-type (WT) MAGEL2, a truncated MAGEL2 mutant was evenly distributed between the cytoplasm and the nucleus. To elucidate regulatory pathways that may underlie both diseases, we identified protein interaction partners for WT or mutant MAGEL2, in particular the survival motor neuron protein (SMN), involved in spinal muscular atrophy, and the fragile-X-messenger ribonucleoprotein (FMRP), involved in autism spectrum disorders. The interactome of the non-coding RNA SNORD116 was also investigated by RNA-CoIP. We show that WT and truncated MAGEL2 were both involved in RNA metabolism, while regulation of transcription was mainly observed for WT MAGEL2. Hence, we investigated the influence of MAGEL2 mutations on the expression of genes from the PWS locus, including the SNORD116 cluster. Thereby, we provide evidence for MAGEL2 mutants decreasing the expression of SNORD116, SNORD115, and SNORD109A, as well as protein-coding genes MKRN3 and SNRPN, thus bridging the gap between PWS and SYS.
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Affiliation(s)
- David Heimdörfer
- Institute of Genomics and RNomics, Biocenter Innsbruck, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
| | - Alexander Vorleuter
- Institute of Genomics and RNomics, Biocenter Innsbruck, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Alexander Eschlböck
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Angeliki Spathopoulou
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Marta Suarez-Cubero
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Hesso Farhan
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Veronika Reiterer
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Melanie Spanjaard
- Institute of Human Genetics, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Christian P Schaaf
- Institute of Human Genetics, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innrain 80/82, Innsbruck 6020, Austria
| | - Leopold Kremser
- Institute of Medical Biochemistry, Protein Core Facility, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Bettina Sarg
- Institute of Medical Biochemistry, Protein Core Facility, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Frank Edenhofer
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Stephan Geley
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Mariana E G de Araujo
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innrain 80/82, Innsbruck 6020, Austria
| | - Alexander Huettenhofer
- Institute of Genomics and RNomics, Biocenter Innsbruck, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
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Ma T, Xiong ES, Lardelli RM, Lykke-Andersen J. Sm complex assembly and 5' cap trimethylation promote selective processing of snRNAs by the 3' exonuclease TOE1. Proc Natl Acad Sci U S A 2024; 121:e2315259121. [PMID: 38194449 PMCID: PMC10801842 DOI: 10.1073/pnas.2315259121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/06/2023] [Indexed: 01/11/2024] Open
Abstract
Competing exonucleases that promote 3' end maturation or degradation direct quality control of small non-coding RNAs, but how these enzymes distinguish normal from aberrant RNAs is poorly understood. The Pontocerebellar Hypoplasia 7 (PCH7)-associated 3' exonuclease TOE1 promotes maturation of canonical small nuclear RNAs (snRNAs). Here, we demonstrate that TOE1 achieves specificity toward canonical snRNAs through their Sm complex assembly and cap trimethylation, two features that distinguish snRNAs undergoing correct biogenesis from other small non-coding RNAs. Indeed, disruption of Sm complex assembly via snRNA mutations or protein depletions obstructs snRNA processing by TOE1, and in vitro snRNA processing by TOE1 is stimulated by a trimethylated cap. An unstable snRNA variant that normally fails to undergo maturation becomes fully processed by TOE1 when its degenerate Sm binding motif is converted into a canonical one. Our findings uncover the molecular basis for how TOE1 distinguishes snRNAs from other small non-coding RNAs and explain how TOE1 promotes maturation specifically of canonical snRNAs undergoing proper processing.
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Affiliation(s)
- Tiantai Ma
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
| | - Erica S. Xiong
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
| | - Rea M. Lardelli
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
| | - Jens Lykke-Andersen
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
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3
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McGinnis MM, Sutter BM, Jahangiri S, Tu BP. Exonuclease Xrn1 regulates TORC1 signaling in response to SAM availability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.559955. [PMID: 37808861 PMCID: PMC10557749 DOI: 10.1101/2023.09.28.559955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Autophagy is a conserved process of cellular self-digestion that promotes survival during nutrient stress. In yeast, methionine starvation is sufficient to induce autophagy. One pathway of autophagy induction is governed by the SEACIT complex, which regulates TORC1 activity in response to amino acids through the Rag GTPases Gtr1 and Gtr2. However, the precise mechanism by which SEACIT senses amino acids and regulates TORC1 signaling remains incompletely understood. Here, we identify the conserved 5'-3' RNA exonuclease Xrn1 as a surprising and novel regulator of TORC1 activity in response to methionine starvation. This role of Xrn1 is dependent on its catalytic activity, but not on degradation of any specific class of mRNAs. Instead, Xrn1 modulates the nucleotide-binding state of the Gtr1/2 complex, which is critical for its interaction with and activation of TORC1. This work identifies a critical role for Xrn1 in nutrient sensing and growth control that extends beyond its canonical housekeeping function in RNA degradation and indicates an avenue for RNA metabolism to function in amino acid signaling into TORC1.
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Affiliation(s)
- Madeline M McGinnis
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Benjamin M Sutter
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Samira Jahangiri
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
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4
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Ma T, Xiong ES, Lardelli RM, Lykke-Andersen J. The 3' exonuclease TOE1 selectively processes snRNAs through recognition of Sm complex assembly and 5' cap trimethylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.15.553431. [PMID: 37645788 PMCID: PMC10462049 DOI: 10.1101/2023.08.15.553431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Competing exonucleases that promote 3' end maturation or degradation direct quality control of small non-coding RNAs, but how these enzymes distinguish normal from aberrant RNAs is poorly understood. The Pontocerebellar Hypoplasia 7 (PCH7)-associated 3' exonuclease TOE1 promotes maturation of canonical small nuclear RNAs (snRNAs). Here, we demonstrate that TOE1 achieves specificity towards canonical snRNAs by recognizing Sm complex assembly and cap trimethylation, two features that distinguish snRNAs undergoing correct biogenesis from other small non-coding RNAs. Indeed, disruption of Sm complex assembly via snRNA mutations or protein depletions obstructs snRNA processing by TOE1, and in vitro snRNA processing by TOE1 is stimulated by a trimethylated cap. An unstable snRNA variant that normally fails to undergo maturation becomes fully processed by TOE1 when its degenerate Sm binding motif is converted into a canonical one. Our findings uncover the molecular basis for how TOE1 distinguishes snRNAs from other small non-coding RNAs and explain how TOE1 promotes maturation specifically of canonical snRNAs undergoing proper processing.
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Affiliation(s)
- Tiantai Ma
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Erica S Xiong
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Rea M Lardelli
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Jens Lykke-Andersen
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
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5
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Nayana RUK, Nakkeeran S, Saranya N, Saravanan R, Mahendra K, Ashraf S, Perveen K, Alshaikh NA, Sayyed RZ, Show PL. Triamcinolone Acetonide Produced by Bacillus velezensis YEBBR6 Exerts Antagonistic Activity Against Fusarium oxysporum f. sp. Cubense: A Computational Analysis. Mol Biotechnol 2023:10.1007/s12033-023-00797-w. [PMID: 37556108 DOI: 10.1007/s12033-023-00797-w] [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: 02/01/2023] [Accepted: 06/13/2023] [Indexed: 08/10/2023]
Abstract
Fusarium oxysporum f. sp. cubense is one of the most severe and threatening pathogens of bananas, causing "Panama wilt" worldwide. Confrontation assay of Foc antagonistic bacterial endophyte, Bacillus velezensis YEBBR6, with the Foc and GC-MS profiling of excised agar from the zone of inhibition, led to the unveiling of secondary metabolites produced by the endophyte. To refine the probable antifungal compounds among the numerous biomolecules formed during their di-trophic interaction with the pathogen, fungal protein targets were modeled, and docking studies (AutoDock Vina module of the PyRx 0.8 server) were done with all the compounds. Triamcinolone acetonide exhibited the most excellent affinity for the protein targets among the compounds studied. It had a maximum binding affinity of 11.2 kcal/mol for XRN2 (5' → 3'). Further, the protein-ligand complex formation kinetics was done through Molecular Dynamic Simulation studies. Graphs for the RMSD, RMSF, Rg, potential energy, and SASA were generated, and the values during the simulation period suggested the stability of the biomolecule as a complex with the protein. This indicated Triamcinolone acetonide's potential ability to act as a functional disrupter of the target protein and likely an antifungal molecule. Further, the biomolecule was tested for its activity against Foc by screening in the wet lab through the poisoned plate technique, and it was found to be fully inhibitory to the growth of the pathogen at 1000 ppm.
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Affiliation(s)
- R U Krishna Nayana
- Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - S Nakkeeran
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India.
| | - N Saranya
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - R Saravanan
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - K Mahendra
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Suhail Ashraf
- Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Kahkashan Perveen
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box-22452, Riyadh, 11495, Saudi Arabia
| | - Najla A Alshaikh
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box-22452, Riyadh, 11495, Saudi Arabia
| | - R Z Sayyed
- Department of Microbiology, PSGVP Mandal's, S. I. Patil Arts, G.B. Patel Science and STKV Sangh Commerce College, Shahada, 425409, India.
- Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800, Nilai, Negeri Sembilan, Malaysia.
| | - Pau Loke Show
- Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou, 325035, China.
- Department of Chemical Engineering, Khalifa University, Shakhbout Bin Sultan St - Zone 1, Abu Dhabi, United Arab Emirates.
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia.
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6
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Schneider C, Bohnsack KE. Caught in the act-Visualizing ribonucleases during eukaryotic ribosome assembly. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1766. [PMID: 36254602 DOI: 10.1002/wrna.1766] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 07/20/2023]
Abstract
Ribosomes are essential macromolecular machines responsible for translating the genetic information encoded in mRNAs into proteins. Ribosomes are composed of ribosomal RNAs and proteins (rRNAs and RPs) and the rRNAs fulfill both catalytic and architectural functions. Excision of the mature eukaryotic rRNAs from their precursor transcript is achieved through a complex series of endoribonucleolytic cleavages and exoribonucleolytic processing steps that are precisely coordinated with other aspects of ribosome assembly. Many ribonucleases involved in pre-rRNA processing have been identified and pre-rRNA processing pathways are relatively well defined. However, momentous advances in cryo-electron microscopy have recently enabled structural snapshots of various pre-ribosomal particles from budding yeast (Saccharomyces cerevisiae) and human cells to be captured and, excitingly, these structures not only allow pre-rRNAs to be observed before and after cleavage events, but also enable ribonucleases to be visualized on their target RNAs. These structural views of pre-rRNA processing in action allow a new layer of understanding of rRNA maturation and how it is coordinated with other aspects of ribosome assembly. They illuminate mechanisms of target recognition by the diverse ribonucleases involved and reveal how the cleavage/processing activities of these enzymes are regulated. In this review, we discuss the new insights into pre-rRNA processing gained by structural analyses and the growing understanding of the mechanisms of ribonuclease regulation. This article is categorized under: Translation > Ribosome Biogenesis RNA Processing > rRNA Processing.
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Affiliation(s)
- Claudia Schneider
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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7
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Aygün I, Rzepczak A, Miki TS. A germline-targeted genetic screen for xrn-2 suppressors identifies a novel gene C34C12.2 in Caenorhabditis elegans. Genet Mol Biol 2023; 46:e20220328. [PMID: 37216322 DOI: 10.1590/1678-4685-gmb-2022-0328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 02/22/2023] [Indexed: 05/24/2023] Open
Abstract
XRN2 is an evolutionarily conserved 5'-to-3' exoribonuclease, which degrades or trims various types of RNA in the nucleus. Although XRN-2 is essential for embryogenesis, larval development and reproduction in Caenorhabditis elegans, relevant molecular pathways remain unidentified. Here we create a germline-specific xrn-2 conditional mutant and perform a mutagenesis screen for suppressors of sterility. Loss-of-function alleles of dpy-10, osr-1, ptr-6 and C34C12.2 genes are identified. Depletion of DPY-10, OSR-1 or PTR-6 increases expression of gpdh-1 that encodes a glycerol-3-phosphate dehydrogenase, thereby elevates glycerol accumulation to suppress sterility of the mutant. The C34C12.2 protein is predominantly localized in the nucleolus of germ cells and shows a similarity to Saccharomyces cerevisiae Net1, which is involved in rDNA silencing. Depletion of NRDE-2, a putative interacting partner of C34C12.2 and a component of the nuclear RNAi machinery, restores fertility to the xrn-2 conditional mutant. These results may help to identify an essential role of XRN-2 in germline development.
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Affiliation(s)
- Ilkin Aygün
- Polish Academy of Sciences, Institute of Bioorganic Chemistry, Department of Developmental Biology, Poznań, Poland
| | - Alicja Rzepczak
- Polish Academy of Sciences, Institute of Bioorganic Chemistry, Department of Developmental Biology, Poznań, Poland
| | - Takashi S Miki
- Polish Academy of Sciences, Institute of Bioorganic Chemistry, Department of Developmental Biology, Poznań, Poland
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8
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Han WY, Hou BH, Lee WC, Chan TC, Lin TH, Chen HM. Arabidopsis mRNA decay landscape shaped by XRN 5'-3' exoribonucleases. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:895-913. [PMID: 36987558 DOI: 10.1111/tpj.16181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 02/18/2023] [Accepted: 03/03/2023] [Indexed: 05/27/2023]
Abstract
5'-3' exoribonucleases (XRNs) play crucial roles in the control of RNA processing, quality, and quantity in eukaryotes. Although genome-wide profiling of RNA decay fragments is now feasible, how XRNs shape the plant mRNA degradome remains elusive. Here, we profiled and analyzed the RNA degradomes of Arabidopsis wild-type and mutant plants with defects in XRN activity. Deficiency of nuclear XRN3 or cytoplasmic XRN4 activity but not nuclear XRN2 activity greatly altered Arabidopsis mRNA decay profiles. Short excised linear introns and cleaved pre-mRNA fragments downstream of polyadenylation sites were polyadenylated and stabilized in the xrn3 mutant, demonstrating the unique function of XRN3 in the removal of cleavage remnants from pre-mRNA processing. Further analysis of stabilized XRN3 substrates confirmed that pre-mRNA 3' end cleavage frequently occurs after adenosine. The most abundant decay intermediates in wild-type plants include not only the primary substrates of XRN4 but also the products of XRN4-mediated cytoplasmic decay. An increase in decay intermediates with 5' ends upstream of a consensus motif in the xrn4 mutant suggests that there is an endonucleolytic cleavage mechanism targeting the 3' untranslated regions of many Arabidopsis mRNAs. However, analysis of decay fragments in the xrn4 mutant indicated that, except for microRNA-directed slicing, endonucleolytic cleavage events in the coding sequence rarely result in major decay intermediates. Together, these findings reveal the major substrates and products of nuclear and cytoplasmic XRNs along Arabidopsis transcripts and provide a basis for precise interpretation of RNA degradome data.
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Affiliation(s)
- Wan-Yin Han
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung-Hsing University, Taichung 40227, Taiwan, and Academia Sinica, Taipei, 11529, Taiwan
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, 40227, Taiwan
| | - Bo-Han Hou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Wen-Chi Lee
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Tze-Ching Chan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Tzu-Hsiang Lin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Ho-Ming Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung-Hsing University, Taichung 40227, Taiwan, and Academia Sinica, Taipei, 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung, 40227, Taiwan
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9
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Webster SF, Ghalei H. Maturation of small nucleolar RNAs: from production to function. RNA Biol 2023; 20:715-736. [PMID: 37796118 PMCID: PMC10557570 DOI: 10.1080/15476286.2023.2254540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2023] [Indexed: 10/06/2023] Open
Abstract
Small Nucleolar RNAs (snoRNAs) are an abundant group of non-coding RNAs with well-defined roles in ribosomal RNA processing, folding and chemical modification. Besides their classic roles in ribosome biogenesis, snoRNAs are also implicated in several other cellular activities including regulation of splicing, transcription, RNA editing, cellular trafficking, and miRNA-like functions. Mature snoRNAs must undergo a series of processing steps tightly regulated by transiently associating factors and coordinated with other cellular processes including transcription and splicing. In addition to their mature forms, snoRNAs can contribute to gene expression regulation through their derivatives and degradation products. Here, we review the current knowledge on mechanisms of snoRNA maturation, including the different pathways of processing, and the regulatory mechanisms that control snoRNA levels and complex assembly. We also discuss the significance of studying snoRNA maturation, highlight the gaps in the current knowledge and suggest directions for future research in this area.
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Affiliation(s)
- Sarah F. Webster
- Biochemistry, Cell, and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia, USA
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
| | - Homa Ghalei
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
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10
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Cortazar MA, Erickson B, Fong N, Pradhan SJ, Ntini E, Bentley DL. Xrn2 substrate mapping identifies torpedo loading sites and extensive premature termination of RNA pol II transcription. Genes Dev 2022; 36:1062-1078. [PMID: 36396340 PMCID: PMC9744234 DOI: 10.1101/gad.350004.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022]
Abstract
The exonuclease torpedo Xrn2 loads onto nascent RNA 5'-PO4 ends and chases down pol II to promote termination downstream from polyA sites. We report that Xrn2 is recruited to preinitiation complexes and "travels" to 3' ends of genes. Mapping of 5'-PO4 ends in nascent RNA identified Xrn2 loading sites stabilized by an active site mutant, Xrn2(D235A). Xrn2 loading sites are approximately two to 20 bases downstream from where CPSF73 cleaves at polyA sites and histone 3' ends. We propose that processing of all mRNA 3' ends comprises cleavage and limited 5'-3' trimming by CPSF73, followed by handoff to Xrn2. A similar handoff occurs at tRNA 3' ends, where cotranscriptional RNase Z cleavage generates novel Xrn2 substrates. Exonuclease-dead Xrn2 increased transcription in 3' flanking regions by inhibiting polyA site-dependent termination. Surprisingly, the mutant Xrn2 also rescued transcription in promoter-proximal regions to the same extent as in 3' flanking regions. eNET-seq revealed Xrn2-mediated degradation of sense and antisense nascent RNA within a few bases of the TSS, where 5'-PO4 ends may be generated by decapping or endonucleolytic cleavage. These results suggest that a major fraction of pol II complexes terminates prematurely close to the start site under normal conditions by an Xrn2-mediated torpedo mechanism.
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Affiliation(s)
- Michael A. Cortazar
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Benjamin Erickson
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Nova Fong
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Sarala J. Pradhan
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Evgenia Ntini
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas (FORTH), Heraklion GR-70013, Greece
| | - David L. Bentley
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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11
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Bailey AD, Talkish J, Ding H, Igel H, Duran A, Mantripragada S, Paten B, Ares M. Concerted modification of nucleotides at functional centers of the ribosome revealed by single-molecule RNA modification profiling. eLife 2022; 11:e76562. [PMID: 35384842 PMCID: PMC9045821 DOI: 10.7554/elife.76562] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/05/2022] [Indexed: 12/02/2022] Open
Abstract
Nucleotides in RNA and DNA are chemically modified by numerous enzymes that alter their function. Eukaryotic ribosomal RNA (rRNA) is modified at more than 100 locations, particularly at highly conserved and functionally important nucleotides. During ribosome biogenesis, modifications are added at various stages of assembly. The existence of differently modified classes of ribosomes in normal cells is unknown because no method exists to simultaneously evaluate the modification status at all sites within a single rRNA molecule. Using a combination of yeast genetics and nanopore direct RNA sequencing, we developed a reliable method to track the modification status of single rRNA molecules at 37 sites in 18 S rRNA and 73 sites in 25 S rRNA. We use our method to characterize patterns of modification heterogeneity and identify concerted modification of nucleotides found near functional centers of the ribosome. Distinct, undermodified subpopulations of rRNAs accumulate upon loss of Dbp3 or Prp43 RNA helicases, suggesting overlapping roles in ribosome biogenesis. Modification profiles are surprisingly resistant to change in response to many genetic and acute environmental conditions that affect translation, ribosome biogenesis, and pre-mRNA splicing. The ability to capture single-molecule RNA modification profiles provides new insights into the roles of nucleotide modifications in RNA function.
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Affiliation(s)
- Andrew D Bailey
- Department of Biomolecular Engineering and Santa Cruz Genomics Institute, University of California, Santa CruzSanta CruzUnited States
| | - Jason Talkish
- RNA Center and Department of Molecular, Cell & Developmental Biology, University of California, Santa CruzSanta CruzUnited States
| | - Hongxu Ding
- Department of Biomolecular Engineering and Santa Cruz Genomics Institute, University of California, Santa CruzSanta CruzUnited States
- Department of Pharmacy Practice & Science, College of Pharmacy, University of ArizonaTucsonUnited States
| | - Haller Igel
- RNA Center and Department of Molecular, Cell & Developmental Biology, University of California, Santa CruzSanta CruzUnited States
| | | | | | - Benedict Paten
- Department of Biomolecular Engineering and Santa Cruz Genomics Institute, University of California, Santa CruzSanta CruzUnited States
| | - Manuel Ares
- RNA Center and Department of Molecular, Cell & Developmental Biology, University of California, Santa CruzSanta CruzUnited States
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12
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Fractional 2'-O-methylation in the ribosomal RNA of Dictyostelium discoideum supports ribosome heterogeneity in Amoebozoa. Sci Rep 2022; 12:1952. [PMID: 35121764 PMCID: PMC8817022 DOI: 10.1038/s41598-022-05447-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/07/2022] [Indexed: 12/02/2022] Open
Abstract
A hallmark of ribosomal RNA (rRNA) are 2′-O-methyl groups that are introduced sequence specifically by box C/D small nucleolar RNAs (snoRNAs) in ribonucleoprotein particles. Most data on this chemical modification and its impact on RNA folding and stability are derived from organisms of the Opisthokonta supergroup. Using bioinformatics and RNA-seq data, we identify 30 novel box C/D snoRNAs in Dictyostelium discoideum, many of which are differentially expressed during the multicellular development of the amoeba. By applying RiboMeth-seq, we find 49 positions in the 17S and 26S rRNA 2′-O-methylated. Several of these nucleotides are substoichiometrically modified, with one displaying dynamic modification levels during development. Using homology-based models for the D. discoideum rRNA secondary structures, we localize many modified nucleotides in the vicinity of the ribosomal A, P and E sites. For most modified positions, a guiding box C/D snoRNA could be identified, allowing to determine idiosyncratic features of the snoRNA/rRNA interactions in the amoeba. Our data from D. discoideum represents the first evidence for ribosome heterogeneity in the Amoebozoa supergroup, allowing to suggest that it is a common feature of all eukaryotes.
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13
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Talross GJS, Deryusheva S, Gall JG. Stable lariats bearing a snoRNA (slb-snoRNA) in eukaryotic cells: A level of regulation for guide RNAs. Proc Natl Acad Sci U S A 2021; 118:e2114156118. [PMID: 34725166 PMCID: PMC8609340 DOI: 10.1073/pnas.2114156118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2021] [Indexed: 12/31/2022] Open
Abstract
Small nucleolar (sno)RNAs guide posttranscriptional modifications essential for the biogenesis and function of their target. The majority of snoRNAs in higher eukaryotes are encoded within introns. They are first released from nascent transcripts in the form of a lariat and rapidly targeted by the debranching enzyme and nuclear exonucleases for linearization and further trimming. In this study, we report that some snoRNAs are encoded within unusually stable intronic RNAs. These intronic sequences can escape the debranching enzyme and accumulate as lariats. Stable lariats bearing a snoRNA, or slb-snoRNA, are associated with snoRNA binding proteins but do not guide posttranscriptional modification. While most slb-snoRNAs accumulate in the nucleus, some can be exported to the cytoplasm. We find that this export competes with snoRNA maturation. Slb-snoRNAs provide a previously unknown layer of regulation to snoRNA and snoRNA binding proteins.
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Affiliation(s)
- Gaëlle J S Talross
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
| | - Svetlana Deryusheva
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
| | - Joseph G Gall
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
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14
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Aygün I, Miki TS. Nuclear RNA Regulation by XRN2 and XTBD Family Proteins. Cell Struct Funct 2021; 46:73-78. [PMID: 34483148 PMCID: PMC10511037 DOI: 10.1247/csf.21041] [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: 07/15/2021] [Accepted: 08/30/2021] [Indexed: 11/11/2022] Open
Abstract
XRN2 is a 5'-to-3' exoribonuclease that is predominantly localized in the nucleus. By degrading or trimming various classes of RNA, XRN2 contributes to essential processes in gene expression such as transcription termination and ribosome biogenesis. Despite limited substrate specificity in vitro, XRN2 targets a specific subset of RNA by interacting with other proteins in cells. Here we review the functions of proteins that have an evolutionarily conserved XRN2-binding domain, XTBD. These proteins modulate activity of XRN2 by stabilizing it, controlling its subcellular localization or recruiting it to specific RNA targets, and thereby impact on various cellular processes.Key words: RNA regulation, XRN2, XTBD, ribosome biogenesis, subcellular localization.
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Affiliation(s)
- Ilkin Aygün
- Department of Developmental Biology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Takashi S. Miki
- Department of Developmental Biology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
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15
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Aquino GRR, Krogh N, Hackert P, Martin R, Gallesio JD, van Nues RW, Schneider C, Watkins NJ, Nielsen H, Bohnsack KE, Bohnsack MT. RNA helicase-mediated regulation of snoRNP dynamics on pre-ribosomes and rRNA 2'-O-methylation. Nucleic Acids Res 2021; 49:4066-4084. [PMID: 33721027 PMCID: PMC8053091 DOI: 10.1093/nar/gkab159] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 02/23/2021] [Accepted: 02/26/2021] [Indexed: 12/18/2022] Open
Abstract
RNA helicases play important roles in diverse aspects of RNA metabolism through their functions in remodelling ribonucleoprotein complexes (RNPs), such as pre-ribosomes. Here, we show that the DEAD box helicase Dbp3 is required for efficient processing of the U18 and U24 intron-encoded snoRNAs and 2′-O-methylation of various sites within the 25S ribosomal RNA (rRNA) sequence. Furthermore, numerous box C/D snoRNPs accumulate on pre-ribosomes in the absence of Dbp3. Many snoRNAs guiding Dbp3-dependent rRNA modifications have overlapping pre-rRNA basepairing sites and therefore form mutually exclusive interactions with pre-ribosomes. Analysis of the distribution of these snoRNAs between pre-ribosome-associated and ‘free’ pools demonstrated that many are almost exclusively associated with pre-ribosomal complexes. Our data suggest that retention of such snoRNPs on pre-ribosomes when Dbp3 is lacking may impede rRNA 2′-O-methylation by reducing the recycling efficiency of snoRNPs and by inhibiting snoRNP access to proximal target sites. The observation of substoichiometric rRNA modification at adjacent sites suggests that the snoRNPs guiding such modifications likely interact stochastically rather than hierarchically with their pre-rRNA target sites. Together, our data provide new insights into the dynamics of snoRNPs on pre-ribosomal complexes and the remodelling events occurring during the early stages of ribosome assembly.
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Affiliation(s)
- Gerald Ryan R Aquino
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Nicolai Krogh
- Department of Cellular and Molecular Medicine, University of Copenhagen, 3B Blegdamsvej, 2200N Copenhagen, Denmark
| | - Philipp Hackert
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Roman Martin
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Jimena Davila Gallesio
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Robert W van Nues
- Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Claudia Schneider
- Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Nicholas J Watkins
- Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 3B Blegdamsvej, 2200N Copenhagen, Denmark.,Genomics group, Faculty of Biosciences and Aquaculture, Nord University, 8049, Bodø, Norway
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.,Göttingen Center for Molecular Biosciences, Georg-August University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
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16
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Lau B, Cheng J, Flemming D, La Venuta G, Berninghausen O, Beckmann R, Hurt E. Structure of the Maturing 90S Pre-ribosome in Association with the RNA Exosome. Mol Cell 2020; 81:293-303.e4. [PMID: 33326748 DOI: 10.1016/j.molcel.2020.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/01/2020] [Accepted: 11/04/2020] [Indexed: 12/12/2022]
Abstract
Ribosome assembly is catalyzed by numerous trans-acting factors and coupled with irreversible pre-rRNA processing, driving the pathway toward mature ribosomal subunits. One decisive step early in this progression is removal of the 5' external transcribed spacer (5'-ETS), an RNA extension at the 18S rRNA that is integrated into the huge 90S pre-ribosome structure. Upon endo-nucleolytic cleavage at an internal site, A1, the 5'-ETS is separated from the 18S rRNA and degraded. Here we present biochemical and cryo-electron microscopy analyses that depict the RNA exosome, a major 3'-5' exoribonuclease complex, in a super-complex with the 90S pre-ribosome. The exosome is docked to the 90S through its co-factor Mtr4 helicase, a processive RNA duplex-dismantling helicase, which strategically positions the exosome at the base of 5'-ETS helices H9-H9', which are dislodged in our 90S-exosome structures. These findings suggest a direct role of the exosome in structural remodeling of the 90S pre-ribosome to drive eukaryotic ribosome synthesis.
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Affiliation(s)
- Benjamin Lau
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Jingdong Cheng
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
| | - Dirk Flemming
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Giuseppe La Venuta
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Otto Berninghausen
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
| | - Roland Beckmann
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany.
| | - Ed Hurt
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
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17
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Mohanta A, Chakrabarti K. Dbr1 functions in mRNA processing, intron turnover and human diseases. Biochimie 2020; 180:134-142. [PMID: 33038423 DOI: 10.1016/j.biochi.2020.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/29/2022]
Abstract
Pre-mRNA processing and mRNA stability play direct roles in controlling protein abundance in a cell. Before the mRNA can be translated into a protein, the introns in the pre-mRNA transcripts need to be removed by splicing, such that exons can be ligated together and can code for a protein. In this process, the function of the RNA lariat debranching enzyme or Dbr1 provides a rate-limiting step in the intron turnover process and possibly regulating the production of translation competent mRNAs. Surprising new roles of Dbr1 are emerging in cellular metabolism which extends beyond intron turnover processes, ranging from splicing regulation to translational control. In this review, we highlight the importance of the Dbr1 enzyme, its structure and how anomalies in its function could relate to various human diseases.
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Affiliation(s)
- Arundhati Mohanta
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA
| | - Kausik Chakrabarti
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA.
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18
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Aceituno-Valenzuela U, Micol-Ponce R, Ponce MR. Genome-wide analysis of CCHC-type zinc finger (ZCCHC) proteins in yeast, Arabidopsis, and humans. Cell Mol Life Sci 2020; 77:3991-4014. [PMID: 32303790 PMCID: PMC11105112 DOI: 10.1007/s00018-020-03518-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 03/06/2020] [Accepted: 03/30/2020] [Indexed: 12/22/2022]
Abstract
The diverse eukaryotic proteins that contain zinc fingers participate in many aspects of nucleic acid metabolism, from DNA transcription to RNA degradation, post-transcriptional gene silencing, and small RNA biogenesis. These proteins can be classified into at least 30 types based on structure. In this review, we focus on the CCHC-type zinc fingers (ZCCHC), which contain an 18-residue domain with the CX2CX4HX4C sequence, where C is cysteine, H is histidine, and X is any amino acid. This motif, also named the "zinc knuckle", is characteristic of the retroviral Group Antigen protein and occurs alone or with other motifs. Many proteins containing zinc knuckles have been identified in eukaryotes, but only a few have been studied. Here, we review the available information on ZCCHC-containing factors from three evolutionarily distant eukaryotes-Saccharomyces cerevisiae, Arabidopsis thaliana, and Homo sapiens-representing fungi, plants, and metazoans, respectively. We performed systematic searches for proteins containing the CX2CX4HX4C sequence in organism-specific and generalist databases. Next, we analyzed the structural and functional information for all such proteins stored in UniProtKB. Excluding retrotransposon-encoded proteins and proteins harboring uncertain ZCCHC motifs, we found seven ZCCHC-containing proteins in yeast, 69 in Arabidopsis, and 34 in humans. ZCCHC-containing proteins mainly localize to the nucleus, but some are nuclear and cytoplasmic, or exclusively cytoplasmic, and one localizes to the chloroplast. Most of these factors participate in RNA metabolism, including transcriptional elongation, polyadenylation, translation, pre-messenger RNA splicing, RNA export, RNA degradation, microRNA and ribosomal RNA biogenesis, and post-transcriptional gene silencing. Several human ZCCHC-containing factors are derived from neofunctionalized retrotransposons and act as proto-oncogenes in diverse neoplastic processes. The conservation of ZCCHCs in orthologs of these three phylogenetically distant eukaryotes suggests that these domains have biologically relevant functions that are not well known at present.
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Affiliation(s)
- Uri Aceituno-Valenzuela
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - Rosa Micol-Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - María Rosa Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain.
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19
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Delan-Forino C, Spanos C, Rappsilber J, Tollervey D. Substrate specificity of the TRAMP nuclear surveillance complexes. Nat Commun 2020; 11:3122. [PMID: 32561742 PMCID: PMC7305330 DOI: 10.1038/s41467-020-16965-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 05/29/2020] [Indexed: 01/01/2023] Open
Abstract
During nuclear surveillance in yeast, the RNA exosome functions together with the TRAMP complexes. These include the DEAH-box RNA helicase Mtr4 together with an RNA-binding protein (Air1 or Air2) and a poly(A) polymerase (Trf4 or Trf5). To better determine how RNA substrates are targeted, we analyzed protein and RNA interactions for TRAMP components. Mass spectrometry identified three distinct TRAMP complexes formed in vivo. These complexes preferentially assemble on different classes of transcripts. Unexpectedly, on many substrates, including pre-rRNAs and pre-mRNAs, binding specificity is apparently conferred by Trf4 and Trf5. Clustering of mRNAs by TRAMP association shows co-enrichment for mRNAs with functionally related products, supporting the significance of surveillance in regulating gene expression. We compared binding sites of TRAMP components with multiple nuclear RNA binding proteins, revealing preferential colocalization of subsets of factors. TRF5 deletion reduces Mtr4 recruitment and increases RNA abundance for mRNAs specifically showing high Trf5 binding.
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Affiliation(s)
- Clémentine Delan-Forino
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
| | - Christos Spanos
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
| | - Juri Rappsilber
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355, Berlin, Germany
| | - David Tollervey
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK.
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20
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Herpes simplex virus encephalitis of childhood: inborn errors of central nervous system cell-intrinsic immunity. Hum Genet 2020; 139:911-918. [PMID: 32040615 DOI: 10.1007/s00439-020-02127-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/02/2020] [Indexed: 12/23/2022]
Abstract
Herpes simplex virus 1 (HSV-1) encephalitis (HSE) is the most common sporadic viral encephalitis in Western countries. Over the last 15 years, human genetic and immunological studies have provided proof-of-principle that childhood HSE can result from inborn errors of central nervous system (CNS)-specific, cell-intrinsic immunity to HSV-1. HSE-causing mutations of eight genes disrupt known (TLR3-dependent IFN-α/β immunity) and novel (dependent on DBR1 or snoRNA31) antiviral mechanisms. Monogenic inborn errors confer susceptibility to forebrain (TLR3-IFN or snoRNA31) or brainstem (DBR1) HSE. Most of these disorders display incomplete clinical penetrance, with the possible exception of DBR1 deficiency. They account for a small, but non-negligible proportion of cases (about 7%). These findings pave the way for the gradual definition of the genetic and immunological architecture of childhood HSE, with both biological and clinical implications.
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21
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Regulation of long non-coding RNAs and genome dynamics by the RNA surveillance machinery. Nat Rev Mol Cell Biol 2020; 21:123-136. [PMID: 32020081 DOI: 10.1038/s41580-019-0209-0] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2019] [Indexed: 02/07/2023]
Abstract
Much of the mammalian genome is transcribed, generating long non-coding RNAs (lncRNAs) that can undergo post-transcriptional surveillance whereby only a subset of the non-coding transcripts is allowed to attain sufficient stability to persist in the cellular milieu and control various cellular functions. Paralleling protein turnover by the proteasome complex, lncRNAs are also likely to exist in a dynamic equilibrium that is maintained through constant monitoring by the RNA surveillance machinery. In this Review, we describe the RNA surveillance factors and discuss the vital role of lncRNA surveillance in orchestrating various biological processes, including the protection of genome integrity, maintenance of pluripotency of embryonic stem cells, antibody-gene diversification, coordination of immune cell activation and regulation of heterochromatin formation. We also discuss examples of human diseases and developmental defects associated with the failure of RNA surveillance mechanisms, further highlighting the importance of lncRNA surveillance in maintaining cell and organism functions and health.
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22
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Parenteau J, Abou Elela S. Introns: Good Day Junk Is Bad Day Treasure. Trends Genet 2019; 35:923-934. [PMID: 31668856 DOI: 10.1016/j.tig.2019.09.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/28/2019] [Accepted: 09/19/2019] [Indexed: 02/01/2023]
Abstract
Introns are ubiquitous in eukaryotic transcripts. They are often viewed as junk RNA but the huge energetic burden of transcribing, removing, and degrading them suggests a significant evolutionary advantage. Ostensibly, an intron functions within the host pre-mRNA to regulate its splicing, transport, and degradation. However, recent studies have revealed an entirely new class of trans-acting functions where the presence of intronic RNA in the cell impacts the expression of other genes in trans. Here, we review possible new mechanisms of intron functions, with a focus on the role of yeast introns in regulating the cell growth response to starvation.
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Affiliation(s)
- Julie Parenteau
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Sherif Abou Elela
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
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23
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Zhang SY, Jouanguy E, Zhang Q, Abel L, Puel A, Casanova JL. Human inborn errors of immunity to infection affecting cells other than leukocytes: from the immune system to the whole organism. Curr Opin Immunol 2019; 59:88-100. [PMID: 31121434 PMCID: PMC6774828 DOI: 10.1016/j.coi.2019.03.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 03/29/2019] [Indexed: 01/19/2023]
Abstract
Studies of vertebrate immunity have traditionally focused on professional cells, including circulating and tissue-resident leukocytes. Evidence that non-professional cells are also intrinsically essential (i.e. not via their effect on leukocytes) for protective immunity in natural conditions of infection has emerged from three lines of research in human genetics. First, studies of Mendelian resistance to infection have revealed an essential role of DARC-expressing erythrocytes in protection against Plasmodium vivax infection, and an essential role of FUT2-expressing intestinal epithelial cells for protection against norovirus and rotavirus infections. Second, studies of inborn errors of non-hematopoietic cell-extrinsic immunity have shown that APOL1 and complement cascade components secreted by hepatocytes are essential for protective immunity to trypanosome and pyogenic bacteria, respectively. Third, studies of inborn errors of non-hematopoietic cell-intrinsic immunity have suggested that keratinocytes, pulmonary epithelial cells, and cortical neurons are essential for tissue-specific protective immunity to human papillomaviruses, influenza virus, and herpes simplex virus, respectively. Various other types of genetic resistance or predisposition to infection in human populations are not readily explained by inborn variants of genes operating in leukocytes and may, therefore, involve defects in other cells. The probing of this unchartered territory by human genetics is reshaping immunology, by scaling immunity to infection up from the immune system to the whole organism.
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Affiliation(s)
- Shen-Ying Zhang
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR 1163, Necker Hospital for Sick Children, 75015 Paris, France; Paris Descartes University, Imagine Institute, 75015 Paris, France
| | - Emmanuelle Jouanguy
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR 1163, Necker Hospital for Sick Children, 75015 Paris, France; Paris Descartes University, Imagine Institute, 75015 Paris, France
| | - Qian Zhang
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Laurent Abel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR 1163, Necker Hospital for Sick Children, 75015 Paris, France; Paris Descartes University, Imagine Institute, 75015 Paris, France
| | - Anne Puel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR 1163, Necker Hospital for Sick Children, 75015 Paris, France; Paris Descartes University, Imagine Institute, 75015 Paris, France
| | - Jean-Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR 1163, Necker Hospital for Sick Children, 75015 Paris, France; Paris Descartes University, Imagine Institute, 75015 Paris, France; Pediatric Hematology-Immunology Unit, Necker Hospital for Sick Children, 75015 Paris, France; Howard Hughes Medical Institute, New York, NY 10065, USA.
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24
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Boivin V, Faucher-Giguère L, Scott M, Abou-Elela S. The cellular landscape of mid-size noncoding RNA. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1530. [PMID: 30843375 PMCID: PMC6619189 DOI: 10.1002/wrna.1530] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/08/2019] [Accepted: 02/09/2019] [Indexed: 01/06/2023]
Abstract
Noncoding RNA plays an important role in all aspects of the cellular life cycle, from the very basic process of protein synthesis to specialized roles in cell development and differentiation. However, many noncoding RNAs remain uncharacterized and the function of most of them remains unknown. Mid-size noncoding RNAs (mncRNAs), which range in length from 50 to 400 nucleotides, have diverse regulatory functions but share many fundamental characteristics. Most mncRNAs are produced from independent promoters although others are produced from the introns of other genes. Many are found in multiple copies in genomes. mncRNAs are highly structured and carry many posttranscriptional modifications. Both of these facets dictate their RNA-binding protein partners and ultimately their function. mncRNAs have already been implicated in translation, catalysis, as guides for RNA modification, as spliceosome components and regulatory RNA. However, recent studies are adding new mncRNA functions including regulation of gene expression and alternative splicing. In this review, we describe the different classes, characteristics and emerging functions of mncRNAs and their relative expression patterns. Finally, we provide a portrait of the challenges facing their detection and annotation in databases. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution.
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Affiliation(s)
- Vincent Boivin
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Laurence Faucher-Giguère
- Department of Microbiology and Infectious Disease, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Michelle Scott
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Sherif Abou-Elela
- Department of Microbiology and Infectious Disease, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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25
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Excised linear introns regulate growth in yeast. Nature 2019; 565:606-611. [PMID: 30651636 DOI: 10.1038/s41586-018-0828-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 11/27/2018] [Indexed: 12/31/2022]
Abstract
Spliceosomal introns are ubiquitous non-coding RNAs that are typically destined for rapid debranching and degradation. Here we describe 34 excised introns in Saccharomyces cerevisiae that-despite being rapidly degraded in log-phase growth-accumulate as linear RNAs under either saturated-growth conditions or other stresses that cause prolonged inhibition of TORC1, which is a key integrator of growth signalling. Introns that become stabilized remain associated with components of the spliceosome and differ from other spliceosomal introns in having a short distance between their lariat branch point and 3' splice site, which is necessary and sufficient for their stabilization. Deletion of these unusual introns is disadvantageous in saturated conditions and causes aberrantly high growth rates in yeast that are chronically challenged with the TORC1 inhibitor rapamycin. The reintroduction of native or engineered stable introns suppresses this aberrant rapamycin response. Thus, excised introns function within the TOR growth-signalling network of S. cerevisiae and, more generally, excised spliceosomal introns can have biological functions.
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Kufel J, Grzechnik P. Small Nucleolar RNAs Tell a Different Tale. Trends Genet 2018; 35:104-117. [PMID: 30563726 DOI: 10.1016/j.tig.2018.11.005] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/16/2018] [Accepted: 11/21/2018] [Indexed: 12/21/2022]
Abstract
Transcribing RNA Polymerase II interacts with multiple factors that orchestrate maturation and stabilisation of messenger RNA. For the majority of noncoding RNAs, the polymerase complex employs entirely different strategies, which usually direct the nascent transcript to ribonucleolytic degradation. However, some noncoding RNA classes use endo- and exonucleases to achieve functionality. Here we review processing of small nucleolar RNAs that are transcribed by RNA Polymerase II as precursors, and whose 5' and 3' ends undergo processing to release mature, functional molecules. The maturation strategies of these noncoding RNAs in various organisms follow a similar pattern but employ different factors and are strictly correlated with genomic organisation of their genes.
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Affiliation(s)
- Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Pawel Grzechnik
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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Kobyłecki K, Drążkowska K, Kuliński TM, Dziembowski A, Tomecki R. Elimination of 01/A'-A0 pre-rRNA processing by-product in human cells involves cooperative action of two nuclear exosome-associated nucleases: RRP6 and DIS3. RNA (NEW YORK, N.Y.) 2018; 24:1677-1692. [PMID: 30266864 PMCID: PMC6239190 DOI: 10.1261/rna.066589.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/17/2018] [Indexed: 05/10/2023]
Abstract
Pre-rRNA processing generates mature 18S, 5.8S, and 28S/25S rRNAs through multistage removal of surrounding 5'-ETS/3'-ETS and intervening ITS1/ITS2 segments. Endonucleolytic activities release by-products, which need to be eliminated. Here, we investigated the interplay of exosome-associated 3'-5' exonucleases DIS3 and RRP6 in rRNA processing and by-product elimination in human cells. In agreement with previous reports, we observed accumulation of 5.8S and 18S precursors upon dysfunction of these enzymes. However, none of these phenotypes was so pronounced as previously overlooked accumulation of short RNA species derived from 5'-ETS (01/A'-A0), in cells with nonfunctional DIS3. We demonstrate that removal of 01/A'-A0 is independent of the XRN2 5'-3' exonucleolytic activity. Instead, it proceeds rapidly after A0 cleavage and occurs exclusively in the 3'-5' direction in several phases-following initiation by an unknown nuclease, the decay is executed by RRP6 with some contribution of DIS3, whereas the ultimate phase involves predominantly DIS3. Our data shed new light onto the role of human exosome in 5'-ETS removal. Furthermore, although 01/A'-A0 degradation involves the action of two nucleases associated with the exosome ring, similarly to 5.8S 3'-end maturation, it is likely that contrary to the latter process, RRP6 acts prior to or redundantly with DIS3.
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Affiliation(s)
- Kamil Kobyłecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Karolina Drążkowska
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland
| | - Tomasz M Kuliński
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Andrzej Dziembowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Rafał Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
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SAMMSON fosters cancer cell fitness by concertedly enhancing mitochondrial and cytosolic translation. Nat Struct Mol Biol 2018; 25:1035-1046. [PMID: 30374086 PMCID: PMC6223542 DOI: 10.1038/s41594-018-0143-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 09/12/2018] [Indexed: 01/09/2023]
Abstract
Synchronization of mitochondrial and cytoplasmic translation rates is critical for the maintenance of cellular fitness, with cancer cells being especially vulnerable to translational uncoupling. Although alterations of cytosolic protein synthesis are common in human cancer, compensating mechanisms in mitochondrial translation remain elusive. Here we show that the malignant long non-coding RNA (lncRNA) SAMMSON promotes a balanced increase in ribosomal RNA (rRNA) maturation and protein synthesis in the cytosol and mitochondria by modulating the localization of CARF, an RNA-binding protein that sequesters the exo-ribonuclease XRN2 in the nucleoplasm, which under normal circumstances limits nucleolar rRNA maturation. SAMMSON interferes with XRN2 binding to CARF in the nucleus by favoring the formation of an aberrant cytoplasmic RNA-protein complex containing CARF and p32, a mitochondrial protein required for the processing of the mitochondrial rRNAs. These data highlight how a single oncogenic lncRNA can simultaneously modulate RNA-protein complex formation in two distinct cellular compartments to promote cell growth.
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The Conserved RNA Exonuclease Rexo5 Is Required for 3' End Maturation of 28S rRNA, 5S rRNA, and snoRNAs. Cell Rep 2018; 21:758-772. [PMID: 29045842 DOI: 10.1016/j.celrep.2017.09.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/16/2017] [Accepted: 09/20/2017] [Indexed: 12/21/2022] Open
Abstract
Non-coding RNA biogenesis in higher eukaryotes has not been fully characterized. Here, we studied the Drosophila melanogaster Rexo5 (CG8368) protein, a metazoan-specific member of the DEDDh 3'-5' single-stranded RNA exonucleases, by genetic, biochemical, and RNA-sequencing approaches. Rexo5 is required for small nucleolar RNA (snoRNA) and rRNA biogenesis and is essential in D. melanogaster. Loss-of-function mutants accumulate improperly 3' end-trimmed 28S rRNA, 5S rRNA, and snoRNA precursors in vivo. Rexo5 is ubiquitously expressed at low levels in somatic metazoan cells but extremely elevated in male and female germ cells. Loss of Rexo5 leads to increased nucleolar size, genomic instability, defective ribosome subunit export, and larval death. Loss of germline expression compromises gonadal growth and meiotic entry during germline development.
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Perumal K, Reddy R. The 3' end formation in small RNAs. Gene Expr 2018; 10:59-78. [PMID: 11868988 PMCID: PMC5977532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Small RNAs are a major class of RNAs along with transfer RNAs, ribosomal RNAs, and messenger RNAs. They vary in size from less than 100 nucleotides to several thousand nucleotides and have been identified and characterized both in prokaryotes and eukaryotes. Small RNAs participate in a variety of cellular functions including regulating RNA synthesis, RNA processing, guiding modifications in RNA, and in transport of proteins. Small RNAs are generated by a series of posttranscriptional processing steps following transcription. While RNA 5' end structure, 5' cap formation, and RNA processing mechanisms have been fairly well characterized, the 3' end processing is poorly understood. Recent data point to an emerging theme in small RNAs metabolism in which the 3' end processing is mediated by the exosome, a large multienzyme complex. In addition to removal of nucleotides by the exosome, there is simultaneous rebuilding of the 3' end of some small RNA by adenylation and/or uridylation. This review presents a picture of both degradative and rebuilding reactions operative on the 3' end of some small RNA molecules in prokaryotes and eukaryotes.
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Affiliation(s)
- Karthika Perumal
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030
| | - Ram Reddy
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030
- Address correspondence to Ram Reddy, Ph.D., Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030. Tel: (713) 798-7906; Fax: (713) 798-3145; E-mail:
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31
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Terns MP, Terns RM. Small nucleolar RNAs: versatile trans-acting molecules of ancient evolutionary origin. Gene Expr 2018; 10:17-39. [PMID: 11868985 PMCID: PMC5977530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The small nucleolar RNAs (snoRNAs) are an abundant class of trans-acting RNAs that function in ribosome biogenesis in the eukaryotic nucleolus. Elegant work has revealed that most known snoRNAs guide modification of pre-ribosomal RNA (pre-rRNA) by base pairing near target sites. Other snoRNAs are involved in cleavage of pre-rRNA by mechanisms that have not yet been detailed. Moreover, our appreciation of the cellular roles of the snoRNAs is expanding with new evidence that snoRNAs also target modification of small nuclear RNAs and messenger RNAs. Many snoRNAs are produced by unorthodox modes of biogenesis including salvage from introns of pre-mRNAs. The recent discovery that homologs of snoRNAs as well as associated proteins exist in the domain Archaea indicates that the RNA-guided RNA modification system is of ancient evolutionary origin. In addition, it has become clear that the RNA component of vertebrate telomerase (an enzyme implicated in cancer and cellular senescence) is related to snoRNAs. During its evolution, vertebrate telomerase RNA appears to have co-opted a snoRNA domain that is essential for the function of telomerase RNA in vivo. The unique properties of snoRNAs are now being harnessed for basic research and therapeutic applications.
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MESH Headings
- Animals
- Base Pairing
- Biological Transport
- Cell Nucleolus/metabolism
- Cell Nucleus/metabolism
- Eukaryotic Cells/metabolism
- Evolution, Molecular
- Methylation
- Prokaryotic Cells/metabolism
- Pseudouridine/metabolism
- RNA/metabolism
- RNA Precursors/metabolism
- RNA Processing, Post-Transcriptional/genetics
- RNA, Archaeal/genetics
- RNA, Archaeal/physiology
- RNA, Catalytic/metabolism
- RNA, Messenger/metabolism
- RNA, Ribosomal/biosynthesis
- RNA, Small Nucleolar/chemistry
- RNA, Small Nucleolar/classification
- RNA, Small Nucleolar/genetics
- RNA, Small Nucleolar/metabolism
- RNA, Small Nucleolar/physiology
- Ribonucleoproteins, Small Nucleolar/metabolism
- Ribosomes/metabolism
- Species Specificity
- Structure-Activity Relationship
- Telomerase/metabolism
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Affiliation(s)
- Michael P Terns
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA.
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33
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Zhang SY, Clark NE, Freije CA, Pauwels E, Taggart AJ, Okada S, Mandel H, Garcia P, Ciancanelli MJ, Biran A, Lafaille FG, Tsumura M, Cobat A, Luo J, Volpi S, Zimmer B, Sakata S, Dinis A, Ohara O, Garcia Reino EJ, Dobbs K, Hasek M, Holloway SP, McCammon K, Hussong SA, DeRosa N, Van Skike CE, Katolik A, Lorenzo L, Hyodo M, Faria E, Halwani R, Fukuhara R, Smith GA, Galvan V, Damha MJ, Al-Muhsen S, Itan Y, Boeke JD, Notarangelo LD, Studer L, Kobayashi M, Diogo L, Fairbrother WG, Abel L, Rosenberg BR, Hart PJ, Etzioni A, Casanova JL. Inborn Errors of RNA Lariat Metabolism in Humans with Brainstem Viral Infection. Cell 2018; 172:952-965.e18. [PMID: 29474921 PMCID: PMC5886375 DOI: 10.1016/j.cell.2018.02.019] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/03/2017] [Accepted: 02/07/2018] [Indexed: 01/05/2023]
Abstract
Viruses that are typically benign sometimes invade the brainstem in otherwise healthy children. We report bi-allelic DBR1 mutations in unrelated patients from different ethnicities, each of whom had brainstem infection due to herpes simplex virus 1 (HSV1), influenza virus, or norovirus. DBR1 encodes the only known RNA lariat debranching enzyme. We show that DBR1 expression is ubiquitous, but strongest in the spinal cord and brainstem. We also show that all DBR1 mutant alleles are severely hypomorphic, in terms of expression and function. The fibroblasts of DBR1-mutated patients contain higher RNA lariat levels than control cells, this difference becoming even more marked during HSV1 infection. Finally, we show that the patients' fibroblasts are highly susceptible to HSV1. RNA lariat accumulation and viral susceptibility are rescued by wild-type DBR1. Autosomal recessive, partial DBR1 deficiency underlies viral infection of the brainstem in humans through the disruption of tissue-specific and cell-intrinsic immunity to viruses.
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Affiliation(s)
- Shen-Ying Zhang
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris 75015, France; Paris Descartes University, Imagine Institute, Paris 75015, France.
| | - Nathaniel E Clark
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Catherine A Freije
- Program in Immunogenomics, The Rockefeller University, New York, NY 10065, USA
| | - Elodie Pauwels
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Allison J Taggart
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Satoshi Okada
- Department of Pediatrics, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima 734-8553, Japan
| | - Hanna Mandel
- Metabolic Unit, Ruth Children's Hospital, Rambam Health Care Campus, Haifa 31096, Israel; Rappaport Faculty of Medicine, Haifa 31096, Israel
| | - Paula Garcia
- Child Developmental Center, Pediatric Hospital, Hospital and University Center of Coimbra, Coimbra 3000-602, Portugal
| | - Michael J Ciancanelli
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Anat Biran
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Fabien G Lafaille
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Miyuki Tsumura
- Department of Pediatrics, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima 734-8553, Japan
| | - Aurélie Cobat
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris 75015, France; Paris Descartes University, Imagine Institute, Paris 75015, France
| | - Jingchuan Luo
- Department of Molecular Biology & Genetics, JHU School of Medicine, Baltimore, MD 21205, USA; Institute for Systems Genetics, NYU Langone Health, New York 10016, NY, USA
| | - Stefano Volpi
- Pediatric and Rheumatology Clinic, Center for Autoinflammatory Diseases and Immunodeficiencies, Istituto Giannina Gaslini and University of Genoa, Genoa 16100, Italy
| | - Bastian Zimmer
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA
| | - Sonoko Sakata
- Department of Pediatrics, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima 734-8553, Japan
| | - Alexandra Dinis
- Pediatric Intensive Care Unit, Pediatric Hospital, Hospital and University Center of Coimbra, Coimbra 3000-075, Portugal
| | - Osamu Ohara
- Department of Technology Development, Kazusa DNA Research Institute, Chiba 292-0818, Japan; Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Eduardo J Garcia Reino
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Kerry Dobbs
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892-1456, USA
| | - Mary Hasek
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA
| | - Stephen P Holloway
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Karen McCammon
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Stacy A Hussong
- Department of Cellular and Integrative Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, TX 78229, USA; South Texas Veterans Health Care System, Department of Veterans Affairs, TX 78229, USA
| | - Nicholas DeRosa
- Department of Cellular and Integrative Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Candice E Van Skike
- Department of Cellular and Integrative Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Adam Katolik
- Department of Chemistry, McGill University, Montréal, QC H3A0B8, Canada
| | - Lazaro Lorenzo
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris 75015, France; Paris Descartes University, Imagine Institute, Paris 75015, France
| | - Maki Hyodo
- Department of Obstetrics and Gynecology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima 734-8553, Japan
| | - Emilia Faria
- Immuno-Allergy Department, Hospital and University of Coimbra, Coimbra 3000-075, Portugal
| | - Rabih Halwani
- Immunology Research Laboratory, Department of Pediatrics, College of Medicine, King Saud University, Riyadh 11461, Saudi Arabia
| | - Rie Fukuhara
- Department of Neonatology, Hiroshima Prefectural Hospital, Hiroshima 734-8115, Japan
| | - Gregory A Smith
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Veronica Galvan
- Department of Cellular and Integrative Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, TX 78229, USA; South Texas Veterans Health Care System, Department of Veterans Affairs, TX 78229, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montréal, QC H3A0B8, Canada
| | - Saleh Al-Muhsen
- Immunology Research Laboratory, Department of Pediatrics, College of Medicine, King Saud University, Riyadh 11461, Saudi Arabia
| | - Yuval Itan
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jef D Boeke
- Department of Molecular Biology & Genetics, JHU School of Medicine, Baltimore, MD 21205, USA; Institute for Systems Genetics, NYU Langone Health, New York 10016, NY, USA
| | - Luigi D Notarangelo
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892-1456, USA
| | - Lorenz Studer
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA
| | - Masao Kobayashi
- Department of Pediatrics, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima 734-8553, Japan
| | - Luisa Diogo
- Pediatric Hospital of Coimbra, Coimbra 3000-075, Portugal
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA; Hassenfeld Child Health Innovation Institute, Brown University, Providence, RI 02912, USA
| | - Laurent Abel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris 75015, France; Paris Descartes University, Imagine Institute, Paris 75015, France
| | - Brad R Rosenberg
- Program in Immunogenomics, The Rockefeller University, New York, NY 10065, USA; Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - P John Hart
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; South Texas Veterans Health Care System, Department of Veterans Affairs, TX 78229, USA; X-ray Crystallography Core Laboratory, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Amos Etzioni
- Rappaport Faculty of Medicine, Haifa 31096, Israel; Immunology Unit, Ruth Children's Hospital, Haifa 31096, Israel
| | - Jean-Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065, USA; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris 75015, France; Paris Descartes University, Imagine Institute, Paris 75015, France; Howard Hughes Medical Institute, New York, NY 10065, USA; Pediatric Immunology-Hematology Unit, Necker Hospital for Sick Children, Paris 75015, France
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Memet I, Doebele C, Sloan KE, Bohnsack MT. The G-patch protein NF-κB-repressing factor mediates the recruitment of the exonuclease XRN2 and activation of the RNA helicase DHX15 in human ribosome biogenesis. Nucleic Acids Res 2017; 45:5359-5374. [PMID: 28115624 PMCID: PMC5435916 DOI: 10.1093/nar/gkx013] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/04/2017] [Indexed: 01/05/2023] Open
Abstract
In eukaryotes, the synthesis of ribosomal subunits, which involves the maturation of the ribosomal (r)RNAs and assembly of ribosomal proteins, requires the co-ordinated action of a plethora of ribosome biogenesis factors. Many of these cofactors remain to be characterized in human cells. Here, we demonstrate that the human G-patch protein NF-κB-repressing factor (NKRF) forms a pre-ribosomal subcomplex with the DEAH-box RNA helicase DHX15 and the 5΄-3΄ exonuclease XRN2. Using UV crosslinking and analysis of cDNA (CRAC), we reveal that NKRF binds to the transcribed spacer regions of the pre-rRNA transcript. Consistent with this, we find that depletion of NKRF, XRN2 or DHX15 impairs an early pre-rRNA cleavage step (A’). The catalytic activity of DHX15, which we demonstrate is stimulated by NKRF functioning as a cofactor, is required for efficient A’ cleavage, suggesting that a structural remodelling event may facilitate processing at this site. In addition, we show that depletion of NKRF or XRN2 also leads to the accumulation of excised pre-rRNA spacer fragments and that NKRF is essential for recruitment of the exonuclease to nucleolar pre-ribosomal complexes. Our findings therefore reveal a novel pre-ribosomal subcomplex that plays distinct roles in the processing of pre-rRNAs and the turnover of excised spacer fragments.
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Affiliation(s)
- Indira Memet
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany
| | - Carmen Doebele
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany
| | - Katherine E Sloan
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany
| | - Markus T Bohnsack
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany.,Göttingen Centre for Molecular Biosciences, Georg-August-University, 37073 Göttingen, Germany
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Boivin V, Deschamps-Francoeur G, Scott MS. Protein coding genes as hosts for noncoding RNA expression. Semin Cell Dev Biol 2017; 75:3-12. [PMID: 28811264 DOI: 10.1016/j.semcdb.2017.08.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 12/17/2022]
Abstract
With the emergence of high-throughput sequence characterization methods and the subsequent improvements in gene annotations, it is becoming increasingly clear that a large proportion of eukaryotic protein-coding genes (as many as 50% in human) serve as host genes for non-coding RNA genes. Amongst the most extensively characterized embedded non-coding RNA genes, small nucleolar RNAs and microRNAs represent abundant families. Encoded individually or clustered, in sense or antisense orientation with respect to their host and independently expressed or dependent on host expression, the genomic characteristics of embedded genes determine their biogenesis and the extent of their relationship with their host gene. Not only can host genes and the embedded genes they harbour be co-regulated and mutually modulate each other, many are functionally coupled playing a role in the same cellular pathways. And while host-non-coding RNA relationships can be highly conserved, mechanisms have been identified, and in particular an association with transposable elements, allowing the appearance of copies of non-coding genes nested in host genes, or the migration of embedded genes from one host gene to another. The study of embedded non-coding genes and their relationship with their host genes increases the complexity of cellular networks and provides important new regulatory links that are essential to properly understand cell function.
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Affiliation(s)
- Vincent Boivin
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Gabrielle Deschamps-Francoeur
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Michelle S Scott
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada.
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Liang XH, Sun H, Nichols JG, Crooke ST. RNase H1-Dependent Antisense Oligonucleotides Are Robustly Active in Directing RNA Cleavage in Both the Cytoplasm and the Nucleus. Mol Ther 2017; 25:2075-2092. [PMID: 28663102 PMCID: PMC5589097 DOI: 10.1016/j.ymthe.2017.06.002] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 06/01/2017] [Accepted: 06/02/2017] [Indexed: 12/14/2022] Open
Abstract
RNase H1-dependent antisense oligonucleotides (ASOs) are active in reducing levels of both cytoplasmic mRNAs and nuclear retained RNAs. Although ASO activity in the nucleus has been well demonstrated, the cytoplasmic activity of ASOs is less clear. Using kinetic and subcellular fractionation studies, we evaluated ASO activity in the cytoplasm. Upon transfection, ASOs targeting exonic regions rapidly reduced cytoplasmically enriched mRNAs, whereas an intron-targeting ASO that only degrades the nuclear pre-mRNA reduced mRNA levels at a slower rate, similar to normal mRNA decay. Importantly, some exon-targeting ASOs can rapidly and vigorously reduce mRNA levels without decreasing pre-mRNA levels, suggesting that pre-existing cytoplasmic mRNAs can be cleaved by RNase H1-ASO treatment. In addition, we expressed a cytoplasm-localized mutant 7SL RNA that contains a partial U16 small nucleolar RNA (snoRNA) sequence. Treatment with an ASO simultaneously reduced both the nuclear U16 snoRNA and the cytoplasmic 7SL mutant RNA as early as 30 min after transfection in an RNase H1-dependent manner. Both the 5′ and 3′ cleavage products of the 7SL mutant RNA were accumulated in the cytoplasm. Together, these results demonstrate that RNase H1-dependent ASOs are robustly active in both the cytoplasm and nucleus.
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Affiliation(s)
- Xue-Hai Liang
- Department of Core Antisense Research, Ionis Pharmaceutics, Inc., Carlsbad, CA 92010, USA.
| | - Hong Sun
- Department of Core Antisense Research, Ionis Pharmaceutics, Inc., Carlsbad, CA 92010, USA
| | - Joshua G Nichols
- Department of Core Antisense Research, Ionis Pharmaceutics, Inc., Carlsbad, CA 92010, USA
| | - Stanley T Crooke
- Department of Core Antisense Research, Ionis Pharmaceutics, Inc., Carlsbad, CA 92010, USA
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37
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Tomecki R, Sikorski PJ, Zakrzewska-Placzek M. Comparison of preribosomal RNA processing pathways in yeast, plant and human cells - focus on coordinated action of endo- and exoribonucleases. FEBS Lett 2017; 591:1801-1850. [PMID: 28524231 DOI: 10.1002/1873-3468.12682] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 12/17/2022]
Abstract
Proper regulation of ribosome biosynthesis is mandatory for cellular adaptation, growth and proliferation. Ribosome biogenesis is the most energetically demanding cellular process, which requires tight control. Abnormalities in ribosome production have severe consequences, including developmental defects in plants and genetic diseases (ribosomopathies) in humans. One of the processes occurring during eukaryotic ribosome biogenesis is processing of the ribosomal RNA precursor molecule (pre-rRNA), synthesized by RNA polymerase I, into mature rRNAs. It must not only be accurate but must also be precisely coordinated with other phenomena leading to the synthesis of functional ribosomes: RNA modification, RNA folding, assembly with ribosomal proteins and nucleocytoplasmic RNP export. A multitude of ribosome biogenesis factors ensure that these events take place in a correct temporal order. Among them are endo- and exoribonucleases involved in pre-rRNA processing. Here, we thoroughly present a wide spectrum of ribonucleases participating in rRNA maturation, focusing on their biochemical properties, regulatory mechanisms and substrate specificity. We also discuss cooperation between various ribonucleolytic activities in particular stages of pre-rRNA processing, delineating major similarities and differences between three representative groups of eukaryotes: yeast, plants and humans.
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Affiliation(s)
- Rafal Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Poland
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Vendramin R, Marine JC, Leucci E. Non-coding RNAs: the dark side of nuclear-mitochondrial communication. EMBO J 2017; 36:1123-1133. [PMID: 28314780 DOI: 10.15252/embj.201695546] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/26/2016] [Accepted: 12/15/2016] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are critical hubs for the integration of several key metabolic processes implicated in cell growth and survival. They originated from bacterial ancestors through endosymbiosis, following the transfer of more than 90% of their endosymbiont genome to the host cell nucleus. Over time, a mutually beneficial symbiotic relationship has been established, which relies on continuous and elaborate signaling mechanisms between this life-essential organelle and its host. The ability of mitochondria to signal their functional state and trigger compensatory and adaptive cellular responses has long been recognized, but the underlying molecular mechanisms involved have remained poorly understood. Recent evidence indicates that non-coding RNAs (ncRNAs) may contribute to the synchronization of a series of essential cellular and mitochondrial biological processes, acting as "messengers" between the nucleus and the mitochondria. Here, we discuss the emerging putative roles of ncRNAs in various bidirectional signaling pathways established between the host cell and its mitochondria, and how the dysregulation of these pathways may lead to aging-related diseases, including cancer, and offer new promising therapeutic avenues.
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Affiliation(s)
- Roberto Vendramin
- Laboratory for Molecular Cancer Biology, Department of Oncology, KU Leuven, Leuven, Belgium.,VIB Center for Cancer Biology, VIB, Leuven, Belgium
| | - Jean-Christophe Marine
- Laboratory for Molecular Cancer Biology, Department of Oncology, KU Leuven, Leuven, Belgium.,VIB Center for Cancer Biology, VIB, Leuven, Belgium
| | - Eleonora Leucci
- Laboratory for Molecular Cancer Biology, Department of Oncology, KU Leuven, Leuven, Belgium .,RNA Molecular Biology, Center for Microscopy and Molecular Imaging, Université Libre de Bruxelles (ULB), Charleroi, Belgium
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39
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Cavaillé J. Box C/D small nucleolar RNA genes and the Prader-Willi syndrome: a complex interplay. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28296064 DOI: 10.1002/wrna.1417] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 12/22/2022]
Abstract
The nucleolus of mammalian cells contains hundreds of box C/D small nucleolar RNAs (SNORDs). Through their ability to base pair with ribosomal RNA precursors, most play important roles in the synthesis and/or activity of ribosomes, either by guiding sequence-specific 2'-O-methylations or by facilitating RNA folding and cleavages. A growing number of SNORD genes with elusive functions have been discovered recently. Intriguingly, the vast majority of them are located in two large, imprinted gene clusters at human chromosome region 15q11q13 (the SNURF-SNRPN domain) and at 14q32 (the DLK1-DIO3 domain) where they are expressed, respectively, only from the paternally and maternally inherited alleles. These placental mammal-specific SNORD genes have many features of the canonical SNORDs that guide 2'-O-methylations, yet they lack obvious complementarity with ribosomal RNAs and, surprisingly, they are processed from large, tandemly repeated genes expressed preferentially in the brain. This review summarizes our understanding of the biology of these peculiar SNORD genes, focusing particularly on SNORD115 and SNORD116 in the SNURF-SNRPN domain. It examines the growing evidence that altered levels of these SNORDs and/or their host-gene transcripts may be a primary cause of Prader-Willi syndrome (PWS; a rare disorder characterized by overeating and obesity) as well as abnormalities in signaling through the 5-HT2C serotonin receptor. Finally, the hypothesis that PWS may be a ribosomopathy (ribosomal disease) is also discussed. WIREs RNA 2017, 8:e1417. doi: 10.1002/wrna.1417 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Jérôme Cavaillé
- Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse; UPS and CNRS, LMBE, Toulouse, France
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40
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Architecture of the 90S Pre-ribosome: A Structural View on the Birth of the Eukaryotic Ribosome. Cell 2017; 166:380-393. [PMID: 27419870 DOI: 10.1016/j.cell.2016.06.014] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/05/2016] [Accepted: 06/01/2016] [Indexed: 12/13/2022]
Abstract
The 90S pre-ribosome is an early biogenesis intermediate formed during co-transcriptional ribosome formation, composed of ∼70 assembly factors and several small nucleolar RNAs (snoRNAs) that associate with nascent pre-rRNA. We report the cryo-EM structure of the Chaetomium thermophilum 90S pre-ribosome, revealing how a network of biogenesis factors including 19 β-propellers and large α-solenoid proteins engulfs the pre-rRNA. Within the 90S pre-ribosome, we identify the UTP-A, UTP-B, Mpp10-Imp3-Imp4, Bms1-Rcl1, and U3 snoRNP modules, which are organized around 5'-ETS and partially folded 18S rRNA. The U3 snoRNP is strategically positioned at the center of the 90S particle to perform its multiple tasks during pre-rRNA folding and processing. The architecture of the elusive 90S pre-ribosome gives unprecedented structural insight into the early steps of pre-rRNA maturation. Nascent rRNA that is co-transcriptionally folded and given a particular shape by encapsulation within a dedicated mold-like structure is reminiscent of how polypeptides use chaperone chambers for their protein folding.
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Kurihara Y. Activity and roles of Arabidopsis thaliana XRN family exoribonucleases in noncoding RNA pathways. JOURNAL OF PLANT RESEARCH 2017; 130:25-31. [PMID: 27988817 DOI: 10.1007/s10265-016-0887-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/28/2016] [Indexed: 05/20/2023]
Abstract
RNA metabolism is mediated by several sophisticated exo- or endo- ribonucleases. XRN family proteins are the conserved 5'-3' exoribonucleases in eukaryotes. A. thaliana genome encodes three XRN homologs (AtXRN2, AtXRN3 and AtXRN4) and their independent or redundant roles, which are possibly plant-specific in some cases, have been reported. AtXRN2 acts in maturation of ribosomal RNAs partially with AtXRN3. AtXRN3 is also involved in elimination of 3' remnants of microRNA precursors and in termination of mRNA transcription events. AtXRN4 degrades not only a small fraction of mRNAs in stress response but also 3' cleavage products of miRNA-mediated cleavage of target mRNAs. Moreover, all AtXRNs are important factors to suppress unexpected RNA silencing occurrence. Thus, this review summarizes and discusses multiple roles of AtXRN exoribonucleases and their relationship with noncoding RNA pathways including RNA silencing pathways.
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Affiliation(s)
- Yukio Kurihara
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
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42
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Intron Lariat RNA Inhibits MicroRNA Biogenesis by Sequestering the Dicing Complex in Arabidopsis. PLoS Genet 2016; 12:e1006422. [PMID: 27870853 PMCID: PMC5147768 DOI: 10.1371/journal.pgen.1006422] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 10/12/2016] [Indexed: 11/19/2022] Open
Abstract
Lariat RNAs formed as by-products of splicing are quickly degraded by the RNA debranching enzyme 1 (DBR1), leading to their turnover. Null dbr1 mutants in both animals and plants are embryo lethal, but the mechanism underlying the lethality remains unclear. Here we characterized a weak mutant allele of DBR1 in Arabidopsis, dbr1-2, and showed that a global increase in lariat RNAs was unexpectedly accompanied by a genome-wide reduction in miRNA accumulation. The dbr1-2 mutation had no effects on expression of miRNA biogenesis genes or primary miRNAs (pri-miRNAs), but the association of pri-miRNAs with the DCL1/HYL1 dicing complex was impaired. Lariat RNAs were associated with the DCL1/HYL1 dicing complex in vivo and competitively inhibited the binding of HYL1 with pri-miRNA. Consistent with the impacts of lariat RNAs on miRNA biogenesis, over-expression of lariat RNAs reduced miRNA accumulation. Lariat RNAs localized in nuclear bodies, and partially co-localize with HYL1, and both DCL1 and HYL1 were mis-localized in dbr1-2. Together with our findings that nearly four hundred lariat RNAs exist in wild type plants and that these lariat RNAs also associate with the DCL1/HYL1 dicing complex in vivo, we thus propose that lariat RNAs, as decoys, inhibit miRNA processing, suggesting a hitherto unknown layer of regulation in miRNA biogenesis. It is known that lariat RNAs formed during pre-mRNA splicing are debranched by DBR1 (RNA debranching enzyme 1). Loss of function of DBR1 causes embryo lethality in both animals and plants. In animals, some debranched lariat RNAs could be further processed into mirtron miRNAs, a class of nonconventional miRNAs that bypass the microprocessor for their biogenesis. However, no mirtron has been functionally validated in plants, and how the accumulation of lariat RNA in dbr1 results in embryo lethality remains unclear. Here, we show that DBR1 is necessary for the regulation of genome-wide miRNA biogenesis in plants. By investigating the correlation between lariat RNA accumulation and miRNA processing, we showed that the DBR1-mediated lariat RNA debranching process provides a safeguard role for the binding of the dicing complex with miRNA precursors. As both the DBR1-mediated lariat RNA debranching process and miRNA biogenesis are common features in higher eukaryotes, the finding that lariat RNAs sequester the dicing complex in plants may have a broad implications for the non-coding RNA field.
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43
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Tripp V, Martin R, Orell A, Alkhnbashi OS, Backofen R, Randau L. Plasticity of archaeal C/D box sRNA biogenesis. Mol Microbiol 2016; 103:151-164. [PMID: 27743417 DOI: 10.1111/mmi.13549] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2016] [Indexed: 01/11/2023]
Abstract
Archaeal and eukaryotic organisms contain sets of C/D box s(no)RNAs with guide sequences that determine ribose 2'-O-methylation sites of target RNAs. The composition of these C/D box sRNA sets is highly variable between organisms and results in varying RNA modification patterns which are important for ribosomal RNA folding and stability. Little is known about the genomic organization of C/D box sRNA genes in archaea. Here, we aimed to obtain first insights into the biogenesis of these archaeal C/D box sRNAs and analyzed the genetic context of more than 300 archaeal sRNA genes. We found that the majority of these genes do not possess independent promoters but are rather located at positions that allow for co-transcription with neighboring genes and their start or stop codons were frequently incorporated into the conserved boxC and D motifs. The biogenesis of plasmid-encoded C/D box sRNA variants was analyzed in vivo in Sulfolobus acidocaldarius. It was found that C/D box sRNA maturation occurs independent of their genetic context and relies solely on the presence of intact RNA kink-turn structures. The observed plasticity of C/D box sRNA biogenesis is suggested to enable their accelerated evolution and, consequently, allow for adjustments of the RNA modification landscape.
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Affiliation(s)
- Vanessa Tripp
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, Marburg, 35043, Germany.,LOEWE Center for Synthetic Microbiology, SYNMIKRO, Karl-von-Frisch-Strasse 16, Marburg, 35043, Germany
| | - Roman Martin
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, Marburg, 35043, Germany
| | - Alvaro Orell
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, Marburg, 35043, Germany
| | - Omer S Alkhnbashi
- Bioinformatics group, Department of Computer Science, University of Freiburg, Georges-Köhler-Allee 106, Freiburg, 79110, Germany
| | - Rolf Backofen
- Bioinformatics group, Department of Computer Science, University of Freiburg, Georges-Köhler-Allee 106, Freiburg, 79110, Germany.,BIOSS Centre for Biological Signalling Studies, Cluster of Excellence, University of Freiburg, Germany
| | - Lennart Randau
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, Marburg, 35043, Germany.,LOEWE Center for Synthetic Microbiology, SYNMIKRO, Karl-von-Frisch-Strasse 16, Marburg, 35043, Germany
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44
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Kumar L, Shamsuzzama, Haque R, Baghel T, Nazir A. Circular RNAs: the Emerging Class of Non-coding RNAs and Their Potential Role in Human Neurodegenerative Diseases. Mol Neurobiol 2016; 54:7224-7234. [PMID: 27796758 DOI: 10.1007/s12035-016-0213-8] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 10/11/2016] [Indexed: 01/01/2023]
Abstract
The exciting world of research with RNAs has to its credit some breakthrough findings that led to newer insights on multiple problems including that of human diseases. After the advent of siRNA, microRNA, and lncRNA, exciting novel molecules called circular RNAs (circRNAs) have been recently described. circRNAs are a class of non-coding RNAs, which are produced by scrambling of exons at the time of splicing. They are primarily produced in the brain region and are naturally present inside the cell. The best known ones so far include a particular type of circRNA namely "circular RNA sponge for miR-7" (ciRS-7 and CDR1as) which is the inhibitor of miR-7 microRNA-known to regulate various diseases like, cancer, neurodegenerative diseases, diabetes, and atherosclerosis. Similarly, another circRNA molecule called circmbl modulates the ratio of linear mRNA by competing with linear muscleblind gene through which it is synthesized. Considering the complex association of these molecules with critical microRNAs and gene families, circRNAs might have important roles in the cause and progression of human diseases. In particular, the multi-factorial nature of neurodegenerative diseases does warrant studies employing novel approaches towards identifying underlying root causes of these ailments. The non-coding RNAs, like circRNAs and microRNAs, could well present a common genetic trigger to multiple factors associated with neurodegenerative diseases. A specific fingerprint of a combination of various marker circRNAs could be explored for early diagnostic purpose as well. Herein, we review the possibility of exploring the role of circRNAs in the context of the central nervous system (CNS) and age-associated neurodegenerative diseases.
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Affiliation(s)
- Lalit Kumar
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India
| | - Shamsuzzama
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India
| | - Rizwanul Haque
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India
| | - Tanvi Baghel
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India
| | - Aamir Nazir
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India.
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45
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Muppavarapu M, Huch S, Nissan T. The cytoplasmic mRNA degradation factor Pat1 is required for rRNA processing. RNA Biol 2016; 13:455-65. [PMID: 26918764 DOI: 10.1080/15476286.2016.1154253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pat1 is a key cytoplasmic mRNA degradation factor, the loss of which severely increases mRNA half-lives. Several recent studies have shown that Pat1 can enter the nucleus and can shuttle between the nucleus and the cytoplasm. As a result, many nuclear roles have been proposed for Pat1. In this study, we analyzed four previously suggested nuclear roles of Pat1 and show that Pat1 is not required for efficient pre-mRNA splicing or pre-mRNA decay in yeast. However, lack of Pat1 results in accumulation of pre-rRNA processing intermediates. Intriguingly, we identified a novel genetic relationship between Pat1 and the rRNA decay machinery, specifically the exosome and the TRAMP complex. While the pre-rRNA processing intermediates that accumulate in the pat1 deletion mutant are, at least to some extent, recognized as aberrant by the rRNA degradation machinery, it is unlikely that these accumulations are the cause of their synthetic sick relationship. Here, we show that the dysregulation of the levels of mRNAs related to ribosome biogenesis could be the cause of the accumulation of the pre-rRNA processing intermediates. Although our results support a role for Pat1 in transcription, they nevertheless suggest that the primary cause of the dysregulated mRNA levels is most likely due to Pat1's role in mRNA decapping and mRNA degradation.
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Affiliation(s)
- Mridula Muppavarapu
- a Department of Molecular Biology , Umeå University , SE-901 87 Umeå , Sweden
| | - Susanne Huch
- a Department of Molecular Biology , Umeå University , SE-901 87 Umeå , Sweden
| | - Tracy Nissan
- a Department of Molecular Biology , Umeå University , SE-901 87 Umeå , Sweden
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46
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Structural basis and function of XRN2 binding by XTB domains. Nat Struct Mol Biol 2016; 23:164-71. [PMID: 26779609 PMCID: PMC4888950 DOI: 10.1038/nsmb.3155] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 12/04/2015] [Indexed: 12/28/2022]
Abstract
The ribonuclease XRN2 is an essential player in RNA metabolism. In Caenorhabditis elegans, XRN2 functions with PAXT-1, which shares a putative XRN2-binding domain (XTBD) with otherwise unrelated mammalian proteins. Here, we characterize structure and function of an XTBD – XRN2 complex. Although XTBD stably interconnects two XRN2 domains through numerous interacting residues, mutation of a single critical residue suffices to disrupt XTBD – XRN2 complexes in vitro, and recapitulates paxt-1 null mutant phenotypes in vivo. Demonstrating conservation of function, vertebrate XTBD-containing proteins bind XRN2 in vitro, and human CDKN2AIPNL (C2AIL) can substitute for PAXT-1 in vivo. In vertebrates, where three distinct XTBD-containing proteins exist, XRN2 may partition to distinct stable heterodimeric complexes, likely differing in subcellular localization or function. In C. elegans, complex formation with the unique PAXT-1 serves to preserve the stability of XRN2 in the absence of substrate.
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47
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Lee CC, Lin TL, Lin JW, Han YT, Huang YT, Hsu YH, Meng M. Promotion of Bamboo Mosaic Virus Accumulation in Nicotiana benthamiana by 5'→3' Exonuclease NbXRN4. Front Microbiol 2016; 6:1508. [PMID: 26779163 PMCID: PMC4702010 DOI: 10.3389/fmicb.2015.01508] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/14/2015] [Indexed: 12/11/2022] Open
Abstract
Bamboo mosaic virus (BaMV) has a 6.4-kb (+) sense RNA genome with a 5' cap and a 3' poly(A) tail. ORF1 of this potexvirus encodes a 155-kDa replication protein responsible for the viral RNA replication/transcription and 5' cap formation. To learn more about the replication complex of BaMV, a protein preparation enriched in the 155-kDa replication protein was obtained from Nicotiana benthamiana by a protocol involving agroinfiltration and immunoprecipitation. Subsequent analysis by SDS-PAGE and mass spectrometry identified a handful of host proteins that may participate in the viral replication. Among them, the cytoplasmic exoribonuclease NbXRN4 particularly caught our attention. NbXRN4 has been shown to have an antiviral activity against Tomato bushy stunt virus and Tomato mosaic virus. In Arabidopsis, the enzyme could reduce RNAi- and miRNA-mediated RNA decay. This study found that downregulation of NbXRN4 greatly decreased BaMV accumulation, while overexpression of NbXRN4 resulted in an opposite effect. Mutations at the catalytically essential residues abolished the function of NbXRN4 in the increase of BaMV accumulation. Nonetheless, NbXRN4 was still able to promote BaMV accumulation in the presence of the RNA silencing suppressor P19. In summary, the replication efficiency of BaMV may be improved by the exoribonuclease activity of NbXRN4.
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Affiliation(s)
- Cheng-Cheng Lee
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - Tzu-Ling Lin
- Graduate Institute of Biotechnology, National Chung Hsing UniversityTaichung, Taiwan; Division of Medicine Centre for Nephrology, University College LondonLondon, UK
| | - Jhe-Wei Lin
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - Yu-Tsung Han
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - Yu-Ting Huang
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - Menghsiao Meng
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
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48
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Alptekin B, Akpinar BA, Budak H. A Comprehensive Prescription for Plant miRNA Identification. FRONTIERS IN PLANT SCIENCE 2016; 7:2058. [PMID: 28174574 PMCID: PMC5258749 DOI: 10.3389/fpls.2016.02058] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 12/23/2016] [Indexed: 05/15/2023]
Abstract
microRNAs (miRNAs) are tiny ribo-regulatory molecules involved in various essential pathways for persistence of cellular life, such as development, environmental adaptation, and stress response. In recent years, miRNAs have become a major focus in molecular biology because of their functional and diagnostic importance. This interest in miRNA research has resulted in the development of many specific software and pipelines for the identification of miRNAs and their specific targets, which is the key for the elucidation of miRNA-modulated gene expression. While the well-recognized importance of miRNAs in clinical research pushed the emergence of many useful computational identification approaches in animals, available software and pipelines are fewer for plants. Additionally, existing approaches suffers from mis-identification and annotation of plant miRNAs since the miRNA mining process for plants is highly prone to false-positives, particularly in cereals which have a highly repetitive genome. Our group developed a homology-based in silico miRNA identification approach for plants, which utilizes two Perl scripts "SUmirFind" and "SUmirFold" and since then, this method helped identify many miRNAs particularly from crop species such as Triticum or Aegliops. Herein, we describe a comprehensive updated guideline by the implementation of two new scripts, "SUmirPredictor" and "SUmirLocator," and refinements to our previous method in order to identify genuine miRNAs with increased sensitivity in consideration of miRNA identification problems in plants. Recent updates enable our method to provide more reliable and precise results in an automated fashion in addition to solutions for elimination of most false-positive predictions, miRNA naming and miRNA mis-annotation. It also provides a comprehensive view to genome/transcriptome-wide location of miRNA precursors as well as their association with transposable elements. The "SUmirPredictor" and "SUmirLocator" scripts are freely available together with a reference high-confidence plant miRNA list.
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Affiliation(s)
- Burcu Alptekin
- Cereal Genomics Lab, Department of Plant Sciences and Plant Pathology, Montana State UniversityBozeman, MT, USA
| | - Bala A. Akpinar
- Sabanci University Nanotechnology Research and Application Centre, Sabanci UniversityIstanbul, Turkey
| | - Hikmet Budak
- Cereal Genomics Lab, Department of Plant Sciences and Plant Pathology, Montana State UniversityBozeman, MT, USA
- *Correspondence: Hikmet Budak
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Pan WA, Tsai HY, Wang SC, Hsiao M, Wu PY, Tsai MD. The RNA recognition motif of NIFK is required for rRNA maturation during cell cycle progression. RNA Biol 2015; 12:255-67. [PMID: 25826659 PMCID: PMC4615200 DOI: 10.1080/15476286.2015.1017221] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ribosome biogenesis governs protein synthesis. NIFK is transactivated by c-Myc, the key regulator of ribosome biogenesis. The biological function of human NIFK is not well established, except that it has been shown to interact with Ki67 and NPM1. Here we report that NIFK is required for cell cycle progression and participates in the ribosome biogenesis via its RNA recognition motif (RRM). We show that silencing of NIFK inhibits cell proliferation through a reversible p53-dependent G1 arrest, possibly by induction of the RPL5/RPL11-mediated nucleolar stress. Mechanistically it is the consequence of impaired maturation of 28S and 5.8S rRNA resulting from inefficient cleavage of internal transcribed spacer (ITS) 1, a critical step in the separation of pre-ribosome to small and large subunits. Complementation of NIFK silencing by mutants shows that RNA-binding ability of RRM is essential for the pre-rRNA processing and G1 progression. More specifically, we validate that the RRM of NIFK preferentially binds to the 5′-region of ITS2 rRNA likely in both sequence specific and secondary structure dependent manners. Our results show how NIFK is involved in cell cycle progression through RRM-dependent pre-rRNA maturation, which could enhance our understanding of the function of NIFK in cell proliferation, and potentially also cancer and ribosomopathies.
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Key Words
- 5S RNP, 5S ribonucleoprotein particle
- CDK1, cyclin dependent kinase 1
- DFC, dense fibrillar component
- ETS/ITS, external/internal transcribed spacers
- GSK3, glycogen synthase kinase 3
- Ki67
- Ki67FHAID, Ki67-FHA interaction domain
- LSU, large subunit
- MDM2, murine double minute 2
- NIFK, Nucleolar protein Interacting with the FHA domain of pKi-67
- NPM1/B23, nucleophosmin
- Noprecipitation
- PAR-CLIP, Photo-Activatable-Ribonucleoside-Enhanced Crosslinking and Immu-pre-rRNAs, rRNA precursors
- REMSA, RNA electrophoresis mobility shift assay
- RNA recognition motif
- RNP1 and 2, ribonucleoprotein motif 1 and 2
- RPL5 and RPL11, large ribosomal protein 5 and 11
- RRM, RNA recognition motif
- cell cycle
- nucleolar stress
- rNIFK, recombinant NIFK
- ribosome biogenesis
- snoRNP, small nucleolar ribonucleoprotein
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Affiliation(s)
- Wen-An Pan
- a Institute of Biological Chemistry; Academia Sinica ; Taipei , Taiwan
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Thoms M, Thomson E, Baßler J, Gnädig M, Griesel S, Hurt E. The Exosome Is Recruited to RNA Substrates through Specific Adaptor Proteins. Cell 2015; 162:1029-38. [PMID: 26317469 DOI: 10.1016/j.cell.2015.07.060] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/18/2015] [Accepted: 07/02/2015] [Indexed: 12/15/2022]
Abstract
The exosome regulates the processing, degradation, and surveillance of a plethora of RNA species. However, little is known about how the exosome recognizes and is recruited to its diverse substrates. We report the identification of adaptor proteins that recruit the exosome-associated helicase, Mtr4, to unique RNA substrates. Nop53, the yeast homolog of the tumor suppressor PICT1, targets Mtr4 to pre-ribosomal particles for exosome-mediated processing, while a second adaptor Utp18 recruits Mtr4 to cleaved rRNA fragments destined for degradation by the exosome. Both Nop53 and Utp18 contain the same consensus motif, through which they dock to the "arch" domain of Mtr4 and target it to specific substrates. These findings show that the exosome employs a general mechanism of recruitment to defined substrates and that this process is regulated through adaptor proteins.
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Affiliation(s)
- Matthias Thoms
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Emma Thomson
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Jochen Baßler
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Marén Gnädig
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Sabine Griesel
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Ed Hurt
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany.
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