1
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Yao J, Xu H, Ferrick-Kiddie EA, Nottingham RM, Wu DC, Ares M, Lambowitz AM. Human cells contain myriad excised linear intron RNAs with links to gene regulation and potential utility as biomarkers. PLoS Genet 2024; 20:e1011416. [PMID: 39325823 DOI: 10.1371/journal.pgen.1011416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 09/03/2024] [Indexed: 09/28/2024] Open
Abstract
A previous study using Thermostable Group II Intron Reverse Transcriptase sequencing (TGIRT-seq) found human plasma contains short (≤300 nt) structured full-length excised linear intron (FLEXI) RNAs with potential to serve as blood-based biomarkers. Here, TGIRT-seq identified >9,000 different FLEXI RNAs in human cell lines, including relatively abundant FLEXIs with cell-type-specific expression patterns. Analysis of public CLIP-seq datasets identified 126 RNA-binding proteins (RBPs) that have binding sites within the region corresponding to the FLEXI or overlapping FLEXI splice sites in pre-mRNAs, including 53 RBPs with binding sites for ≥30 different FLEXIs. These included splicing factors, transcription factors, a chromatin remodeling protein, cellular growth regulators, and proteins with cytoplasmic functions. Analysis of ENCODE datasets identified subsets of these RBPs whose knockdown impacted FLEXI host gene mRNA levels or proximate alternative splicing, indicating functional interactions. Hierarchical clustering identified six subsets of RBPs whose FLEXI binding sites were co-enriched in six subsets of functionally related host genes: AGO1-4 and DICER, including but not limited to agotrons or mirtron pre-miRNAs; DKC1, NOLC1, SMNDC1, and AATF (Apoptosis Antagonizing Transcription Factor), including but not limited to snoRNA-encoding FLEXIs; two subsets of alternative splicing factors; and two subsets that included RBPs with cytoplasmic functions (e.g., LARP4, PABPC4, METAP2, and ZNF622) together with regulatory proteins. Cell fractionation experiments showed cytoplasmic enrichment of FLEXI RNAs with binding sites for RBPs with cytoplasmic functions. The subsets of host genes encoding FLEXIs with binding sites for different subsets of RBPs were co-enriched with non-FLEXI other short and long introns with binding sites for the same RBPs, suggesting overarching mechanisms for coordinately regulating expression of functionally related genes. Our findings identify FLEXIs as a previously unrecognized large class of cellular RNAs and provide a comprehensive roadmap for further analyzing their biological functions and the relationship of their RBPs to cellular regulatory mechanisms.
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Affiliation(s)
- Jun Yao
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin, Texas, United States of America
| | - Hengyi Xu
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin, Texas, United States of America
| | - Elizabeth A Ferrick-Kiddie
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin, Texas, United States of America
| | - Ryan M Nottingham
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin, Texas, United States of America
| | - Douglas C Wu
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin, Texas, United States of America
| | - Manuel Ares
- Department of Molecular, Cell, and Developmental Biology University of California, Santa Cruz, California, United States of America
| | - Alan M Lambowitz
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin, Texas, United States of America
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2
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Wu C, Wang X, Li Y, Zhen W, Wang C, Wang X, Xie Z, Xu X, Guo S, Botella JR, Zheng B, Wang W, Song CP, Hu Z. Sequestration of DBR1 to stress granules promotes lariat intronic RNAs accumulation for heat-stress tolerance. Nat Commun 2024; 15:7696. [PMID: 39227617 PMCID: PMC11371829 DOI: 10.1038/s41467-024-52034-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 08/22/2024] [Indexed: 09/05/2024] Open
Abstract
Heat stress (HS) poses a significant challenge to plant survival, necessitating sophisticated molecular mechanisms to maintain cellular homeostasis. Here, we identify SICKLE (SIC) as a key modulator of HS responses in Arabidopsis (Arabidopsis thaliana). SIC is required for the sequestration of RNA DEBRANCHING ENZYME 1 (DBR1), a rate-limiting enzyme of lariat intronic RNA (lariRNA) decay, into stress granules (SGs). The sequestration of DBR1 by SIC enhances the accumulation of lariRNAs, branched circular RNAs derived from excised introns during pre-mRNA splicing, which in turn promote the transcription of their parental genes. Our findings further demonstrate that SIC-mediated DBR1 sequestration in SGs is crucial for plant HS tolerance, as deletion of the N-terminus of SIC (SIC1-244) impairs DBR1 sequestration and compromises plant response to HS. Overall, our study unveils a mechanism of transcriptional regulation in the HS response, where lariRNAs are enriched through DBR1 sequestration, ultimately promoting the transcription of heat stress tolerance genes.
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Affiliation(s)
- Chengyun Wu
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
- Sanya Institute, Henan University, Sanya, 572025, China
- The National Engineering Lab of Crop Stress Resistance Breeding, School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Xingsong Wang
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Yan Li
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Weibo Zhen
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Chunfei Wang
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Xiaoqing Wang
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Zhouli Xie
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Xiumei Xu
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
- Sanya Institute, Henan University, Sanya, 572025, China
| | - Siyi Guo
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
- Sanya Institute, Henan University, Sanya, 572025, China
| | - José Ramón Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Wei Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Center for Life Sciences, Beijing, 100871, China
| | - Chun-Peng Song
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China.
- Sanya Institute, Henan University, Sanya, 572025, China.
| | - Zhubing Hu
- The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China.
- Sanya Institute, Henan University, Sanya, 572025, China.
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3
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Chan YH, Lundberg V, Le Pen J, Yuan J, Lee D, Pinci F, Volpi S, Nakajima K, Bondet V, Åkesson S, Khobrekar NV, Bodansky A, Du L, Melander T, Mariaggi AA, Seeleuthner Y, Saleh TS, Chakravarty D, Marits P, Dobbs K, Vonlanthen S, Hennings V, Thörn K, Rinchai D, Bizien L, Chaldebas M, Sobh A, Özçelik T, Keles S, AlKhater SA, Prando C, Meyts I, Wilson MR, Rosain J, Jouanguy E, Aubart M, Abel L, Mogensen TH, Pan-Hammarström Q, Gao D, Duffy D, Cobat A, Berg S, Notarangelo LD, Harschnitz O, Rice CM, Studer L, Casanova JL, Ekwall O, Zhang SY. SARS-CoV-2 brainstem encephalitis in human inherited DBR1 deficiency. J Exp Med 2024; 221:e20231725. [PMID: 39023559 PMCID: PMC11256911 DOI: 10.1084/jem.20231725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 05/14/2024] [Accepted: 06/20/2024] [Indexed: 07/20/2024] Open
Abstract
Inherited deficiency of the RNA lariat-debranching enzyme 1 (DBR1) is a rare etiology of brainstem viral encephalitis. The cellular basis of disease and the range of viral predisposition are unclear. We report inherited DBR1 deficiency in a 14-year-old boy who suffered from isolated SARS-CoV-2 brainstem encephalitis. The patient is homozygous for a previously reported hypomorphic and pathogenic DBR1 variant (I120T). Consistently, DBR1 I120T/I120T fibroblasts from affected individuals from this and another unrelated kindred have similarly low levels of DBR1 protein and high levels of RNA lariats. DBR1 I120T/I120T human pluripotent stem cell (hPSC)-derived hindbrain neurons are highly susceptible to SARS-CoV-2 infection. Exogenous WT DBR1 expression in DBR1 I120T/I120T fibroblasts and hindbrain neurons rescued the RNA lariat accumulation phenotype. Moreover, expression of exogenous RNA lariats, mimicking DBR1 deficiency, increased the susceptibility of WT hindbrain neurons to SARS-CoV-2 infection. Inborn errors of DBR1 impair hindbrain neuron-intrinsic antiviral immunity, predisposing to viral infections of the brainstem, including that by SARS-CoV-2.
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Affiliation(s)
- Yi-Hao Chan
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
| | - Vanja Lundberg
- Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Jérémie Le Pen
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Jiayi Yuan
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, NY, USA
| | - Danyel Lee
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | | | - Stefano Volpi
- Rheumatology and Autoinflammatory Diseases, IRCCS Giannina Gaslini Institute, Genoa, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Koji Nakajima
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
| | - Vincent Bondet
- Translational Immunology Unit, Institut Pasteur, Paris City University, Paris, France
| | - Sanna Åkesson
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Noopur V. Khobrekar
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, NY, USA
| | - Aaron Bodansky
- Department of Pediatrics, Division of Critical Care, University of California San Francisco, San Francisco, CA, USA
| | - Likun Du
- Department of Medical Biochemistry and Biophysics, Division of Immunology, Karolinska Institutet, Stockholm, Sweden
| | - Tina Melander
- Department of Pediatrics, Härnösand Hospital, Region Västernorrland, Sundsvall, Sweden
| | - Alice-Andrée Mariaggi
- Laboratory of Virology, Assistance Publique-Hôpitaux de Paris (AP-HP), Cochin Hospital, Paris, France
| | - Yoann Seeleuthner
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | - Tariq Shikh Saleh
- Department of Pediatric Dentistry, Sundsvall, Region Västernorrland, Sundsvall, Sweden
| | - Debanjana Chakravarty
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Per Marits
- Department of Medicine, Huddinge, Hematology Unit, Therapeutic Immunology and Transfusion, Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Kerry Dobbs
- Division of Intramural Research, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sofie Vonlanthen
- Department of Medicine, Huddinge, Hematology Unit, Therapeutic Immunology and Transfusion, Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Viktoria Hennings
- Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Karolina Thörn
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Darawan Rinchai
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
| | - Lucy Bizien
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | - Matthieu Chaldebas
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
| | - Ali Sobh
- Department of Pediatrics, Mansoura University Children’s Hospital, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Tayfun Özçelik
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | | | - Suzan A. AlKhater
- College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
- Department of Pediatrics, King Fahad University Hospital, Al-Khobar, Saudi Arabia
| | - Carolina Prando
- Faculty of Pequeno Príncipe, Pesquisa Pelé Pequeno Príncipe Institute, Curitiba, Brazil
| | - Isabelle Meyts
- Department of Pediatrics, University Hospitals Leuven, Laboratory for Inborn Errors of Immunity, KU Leuven, Leuven, Belgium
| | - Michael R. Wilson
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Jérémie Rosain
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | - Emmanuelle Jouanguy
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | - Mélodie Aubart
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
- Department of Pediatric Neurology, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Laurent Abel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | | | - Qiang Pan-Hammarström
- Department of Medical Biochemistry and Biophysics, Division of Immunology, Karolinska Institutet, Stockholm, Sweden
| | - Daxing Gao
- Division of Life Science and Medicine, Department of General Surgery, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, China
- Division of Life Sciences and Medicine, Institute of Immunology and the CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, China
| | - Darragh Duffy
- Translational Immunology Unit, Institut Pasteur, Paris City University, Paris, France
| | - Aurélie Cobat
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
| | - Stefan Berg
- Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Luigi D. Notarangelo
- Division of Intramural Research, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | - Charles M. Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Lorenz Studer
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, NY, USA
| | - Jean-Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
- Department of Pediatrics, Necker Hospital for Sick Children, AP-HP, Paris, France
- Howard Hughes Medical Institute, New York, NY, USA
| | - Olov Ekwall
- Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Shen-Ying Zhang
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, Paris, France
- Paris City University, Imagine Institute, Paris, France
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4
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Zhang Y, Zhang X, Tang Q, Li L, Jiang T, Fang Y, Zhang H, Zhai J, Ren G, Zheng B. A repertoire of intronic lariat RNAs reveals tissue-specific regulation and target mimicry potential in plants. SCIENCE CHINA. LIFE SCIENCES 2024; 67:1280-1291. [PMID: 38489006 DOI: 10.1007/s11427-023-2466-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 09/28/2023] [Indexed: 03/17/2024]
Abstract
Lariat RNA is concomitantly produced by excised intron during RNA splicing, which is usually debranched by DBR1, an RNA debranching enzyme. However, increasing evidence showed that some lariat RNA could escape debranching. Little is known about how and why these lariat RNAs could be retained. By comparing the atlas of lariat RNAs between the non-dividing cell (mature pollen) and three actively dividing tissues (young shoot apex, young seeds, and young roots), we identified hundreds to thousands of lariat RNA naturally retained in each tissue, and the incidence of lariat RNA retention is much less in shoot apex while much more in pollen. Many lariat RNAs derived from the same intron or different lariat RNAs from the same pre-mRNA could be retained in one tissue while degraded in the other tissues. By deciphering lariat RNA sequences, we identified an AG-rich (RAAAAVAAAR) motif and a UC-rich (UCUCUYUCUC) motif for pollen-specific and the other three tissues-retained lariat RNAs, respectively. Reconstitution of the pollen-specific AG-rich motif indeed enhanced lariat RNA retention in plants. Biologically, hundreds of lariat RNAs harbored miRNA binding sites, and dual-luciferase reporter assay showed that these natural lariat RNAs had the potential to protect expression of miRNA target genes. Collectively, our results uncover that selective retention of lariat RNA is an actively regulatory process, and provide new insights into understanding how lariat RNA metabolism may impact miRNA activity.
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Affiliation(s)
- Yong Zhang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Xiaotuo Zhang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Qi Tang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Lei Li
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Ting Jiang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Yixiao Fang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Hong Zhang
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jixian Zhai
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Guodong Ren
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China.
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5
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Buerer L, Clark NE, Welch A, Duan C, Taggart AJ, Townley BA, Wang J, Soemedi R, Rong S, Lin CL, Zeng Y, Katolik A, Staley JP, Damha MJ, Mosammaparast N, Fairbrother WG. The debranching enzyme Dbr1 regulates lariat turnover and intron splicing. Nat Commun 2024; 15:4617. [PMID: 38816363 PMCID: PMC11139901 DOI: 10.1038/s41467-024-48696-1] [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: 05/23/2023] [Accepted: 05/05/2024] [Indexed: 06/01/2024] Open
Abstract
The majority of genic transcription is intronic. Introns are removed by splicing as branched lariat RNAs which require rapid recycling. The branch site is recognized during splicing catalysis and later debranched by Dbr1 in the rate-limiting step of lariat turnover. Through generation of a viable DBR1 knockout cell line, we find the predominantly nuclear Dbr1 enzyme to encode the sole debranching activity in human cells. Dbr1 preferentially debranches substrates that contain canonical U2 binding motifs, suggesting that branchsites discovered through sequencing do not necessarily represent those favored by the spliceosome. We find that Dbr1 also exhibits specificity for particular 5' splice site sequences. We identify Dbr1 interactors through co-immunoprecipitation mass spectrometry. We present a mechanistic model for Dbr1 recruitment to the branchpoint through the intron-binding protein AQR. In addition to a 20-fold increase in lariats, Dbr1 depletion increases exon skipping. Using ADAR fusions to timestamp lariats, we demonstrate a defect in spliceosome recycling. In the absence of Dbr1, spliceosomal components remain associated with the lariat for a longer period of time. As splicing is co-transcriptional, slower recycling increases the likelihood that downstream exons will be available for exon skipping.
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Affiliation(s)
- Luke Buerer
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Nathaniel E Clark
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Anastasia Welch
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Chaorui Duan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Allison J Taggart
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Brittany A Townley
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jing Wang
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Rachel Soemedi
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Stephen Rong
- Center for Computational Molecular Biology, Brown University, Providence, RI, 02912, USA
- Department of Genetics, Yale University, New Haven, CT, 06520, USA
| | - Chien-Ling Lin
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan
| | - Yi Zeng
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, 60637, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Adam Katolik
- Department of Chemistry, McGill University, Montreal, QC, H3A 0B8, Canada
| | - Jonathan P Staley
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, QC, H3A 0B8, Canada
| | - Nima Mosammaparast
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA.
- Center for Computational Molecular Biology, Brown University, Providence, RI, 02912, USA.
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6
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Theil AF, Pines A, Kalayci T, Heredia‐Genestar JM, Raams A, Rietveld MH, Sridharan S, Tanis SEJ, Mulder KW, Büyükbabani N, Karaman B, Uyguner ZO, Kayserili H, Hoeijmakers JHJ, Lans H, Demmers JAA, Pothof J, Altunoglu U, El Ghalbzouri A, Vermeulen W. Trichothiodystrophy-associated MPLKIP maintains DBR1 levels for proper lariat debranching and ectodermal differentiation. EMBO Mol Med 2023; 15:e17973. [PMID: 37800682 PMCID: PMC10630875 DOI: 10.15252/emmm.202317973] [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: 05/10/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/07/2023] Open
Abstract
The brittle hair syndrome Trichothiodystrophy (TTD) is characterized by variable clinical features, including photosensitivity, ichthyosis, growth retardation, microcephaly, intellectual disability, hypogonadism, and anaemia. TTD-associated mutations typically cause unstable mutant proteins involved in various steps of gene expression, severely reducing steady-state mutant protein levels. However, to date, no such link to instability of gene-expression factors for TTD-associated mutations in MPLKIP/TTDN1 has been established. Here, we present seven additional TTD individuals with MPLKIP mutations from five consanguineous families, with a newly identified MPLKIP variant in one family. By mass spectrometry-based interaction proteomics, we demonstrate that MPLKIP interacts with core splicing factors and the lariat debranching protein DBR1. MPLKIP-deficient primary fibroblasts have reduced steady-state DBR1 protein levels. Using Human Skin Equivalents (HSEs), we observed impaired keratinocyte differentiation associated with compromised splicing and eventually, an imbalanced proteome affecting skin development and, interestingly, also the immune system. Our data show that MPLKIP, through its DBR1 stabilizing role, is implicated in mRNA splicing, which is of particular importance in highly differentiated tissue.
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Affiliation(s)
- Arjan F Theil
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Alex Pines
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Tuğba Kalayci
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | | | - Anja Raams
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Marion H Rietveld
- Department of DermatologyLeiden University Medical Center (LUMC)LeidenThe Netherlands
| | - Sriram Sridharan
- Cancer Science Institute of SingaporeNational University of SingaporeSingaporeSingapore
| | - Sabine EJ Tanis
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life SciencesRadboud UniversityNijmegenThe Netherlands
| | - Klaas W Mulder
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life SciencesRadboud UniversityNijmegenThe Netherlands
| | - Nesimi Büyükbabani
- Department of Pathology, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University HospitalIstanbulTurkey
| | - Birsen Karaman
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Pediatric Basic Sciences, Child Health InstituteIstanbul UniversityIstanbulTurkey
| | - Zehra O Uyguner
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | - Hülya Kayserili
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University School of Medicine (KUSOM)IstanbulTurkey
| | - Jan HJ Hoeijmakers
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
- Institute for Genome Stability in Aging and Disease, CECAD ForschungszentrumUniversity Hospital of CologneKölnGermany
- Princess Máxima Center for Pediatric OncologyONCODE InstituteUtrechtThe Netherlands
| | - Hannes Lans
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | | | - Joris Pothof
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Umut Altunoglu
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University School of Medicine (KUSOM)IstanbulTurkey
| | | | - Wim Vermeulen
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
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7
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Shamseldin HE, Sadagopan M, Martini J, Al-Ali R, Radefeldt M, Ataei M, Lemke S, Rahbeeni Z, Al Mutairi F, Ababneh F, AlRukban HA, Abdulwahab F, Alhajj SM, Bauer P, Bertoli-Avella A, Alkuraya FS. A founder DBR1 variant causes a lethal form of congenital ichthyosis. Hum Genet 2023; 142:1491-1498. [PMID: 37656279 DOI: 10.1007/s00439-023-02597-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/18/2023] [Indexed: 09/02/2023]
Abstract
DBR1 encodes the only known human lariat debranching enzyme and its deficiency has been found to cause an autosomal recessive inborn error of immunity characterized by pediatric brainstem viral-induced encephalitis (MIM 619441). We describe a distinct allelic disorder caused by a founder recessive DBR1 variant in four families (DBR1(NM_016216.4):c.200A > G (p.Tyr67Cys)). Consistent features include prematurity, severe intrauterine growth deficiency, congenital ichthyosis-like presentation (collodion membrane, severe skin peeling and xerosis), and death before the first year of life. Patient-derived fibroblasts displayed the characteristic accumulation of intron lariats in their RNA as revealed by targeted and untargeted analysis, in addition to a marked reduction of DBR1 on immunoblot analysis. We propose a novel DBR1-related developmental disorder that is distinct from DBR1-related encephalitis susceptibility and highlight the apparent lack of correlation with the degree of DBR1 deficiency.
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Affiliation(s)
- Hanan E Shamseldin
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | | | | | | | | | | | | | - Zuhair Rahbeeni
- Department of Medical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fuad Al Mutairi
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Faroug Ababneh
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Hadeel A AlRukban
- Department of Pediatrics, King Abdullah Bin Abdulaziz University Hospital, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Firdous Abdulwahab
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Saleh Mohammed Alhajj
- Department of Medical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Peter Bauer
- CENTOGENE GmbH, Rostock, Germany
- University Medicine Rostock, Center for internal Medicine, Rostock, Germany
| | | | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
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8
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Clark NE, Katolik A, Gallant P, Welch A, Murphy E, Buerer L, Schorl C, Naik N, Naik MT, Holloway SP, Cano K, Weintraub ST, Howard KM, Hart PJ, Jogl G, Damha MJ, Fairbrother WG. Activation of human RNA lariat debranching enzyme Dbr1 by binding protein TTDN1 occurs though an intrinsically disordered C-terminal domain. J Biol Chem 2023; 299:105100. [PMID: 37507019 PMCID: PMC10470207 DOI: 10.1016/j.jbc.2023.105100] [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: 04/26/2023] [Revised: 07/11/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
In eukaryotic cells, the introns are excised from pre-mRNA by the spliceosome. These introns typically have a lariat configuration due to the 2'-5' phosphodiester bond between an internal branched residue and the 5' terminus of the RNA. The only enzyme known to selectively hydrolyze the 2'-5' linkage of these lariats is the RNA lariat debranching enzyme Dbr1. In humans, Dbr1 is involved in processes such as class-switch recombination of immunoglobulin genes, and its dysfunction is implicated in viral encephalitis, HIV, ALS, and cancer. However, mechanistic details of precisely how Dbr1 affects these processes are missing. Here we show that human Dbr1 contains a disordered C-terminal domain through sequence analysis and nuclear magnetic resonance. This domain stabilizes Dbr1 in vitro by reducing aggregation but is dispensable for debranching activity. We establish that Dbr1 requires Fe2+ for efficient catalysis and demonstrate that the noncatalytic protein Drn1 and the uncharacterized protein trichothiodystrophy nonphotosensitive 1 directly bind to Dbr1. We demonstrate addition of trichothiodystrophy nonphotosensitive 1 to in vitro debranching reactions increases the catalytic efficiency of human Dbr1 19-fold but has no effect on the activity of Dbr1 from the amoeba Entamoeba histolytica, which lacks a disordered C-terminal domain. Finally, we systematically examine how the identity of the branchpoint nucleotide affects debranching rates. These findings describe new aspects of Dbr1 function in humans and further clarify how Dbr1 contributes to human health and disease.
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Affiliation(s)
- Nathaniel E Clark
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA.
| | - Adam Katolik
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
| | - Pascal Gallant
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
| | - Anastasia Welch
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Eileen Murphy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Luke Buerer
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Christoph Schorl
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Nandita Naik
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Mandar T Naik
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Stephen P Holloway
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Kristin Cano
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Katherine M Howard
- Department of Biomedical Sciences, School of Dental Medicine, University of Nevada-Las Vegas, Las Vegas, Nevada, USA
| | - P John Hart
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Gerwald Jogl
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec, Canada.
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA.
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9
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Townley BA, Buerer L, Tsao N, Bacolla A, Mansoori F, Rusanov T, Clark N, Goodarzi N, Schmidt N, Srivatsan SN, Sun H, Sample RA, Brickner JR, McDonald D, Tsai MS, Walter MJ, Wozniak DF, Holehouse AS, Pena V, Tainer JA, Fairbrother WG, Mosammaparast N. A functional link between lariat debranching enzyme and the intron-binding complex is defective in non-photosensitive trichothiodystrophy. Mol Cell 2023; 83:2258-2275.e11. [PMID: 37369199 PMCID: PMC10483886 DOI: 10.1016/j.molcel.2023.06.011] [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: 06/20/2022] [Revised: 03/25/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023]
Abstract
The pre-mRNA life cycle requires intron processing; yet, how intron-processing defects influence splicing and gene expression is unclear. Here, we find that TTDN1/MPLKIP, which is encoded by a gene implicated in non-photosensitive trichothiodystrophy (NP-TTD), functionally links intron lariat processing to spliceosomal function. The conserved TTDN1 C-terminal region directly binds lariat debranching enzyme DBR1, whereas its N-terminal intrinsically disordered region (IDR) binds the intron-binding complex (IBC). TTDN1 loss, or a mutated IDR, causes significant intron lariat accumulation, as well as splicing and gene expression defects, mirroring phenotypes observed in NP-TTD patient cells. A Ttdn1-deficient mouse model recapitulates intron-processing defects and certain neurodevelopmental phenotypes seen in NP-TTD. Fusing DBR1 to the TTDN1 IDR is sufficient to recruit DBR1 to the IBC and circumvents the functional requirement for TTDN1. Collectively, our findings link RNA lariat processing with splicing outcomes by revealing the molecular function of TTDN1.
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Affiliation(s)
- Brittany A Townley
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Luke Buerer
- Center for Computational Molecular Biology, Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912, USA
| | - Ning Tsao
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Fadhel Mansoori
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timur Rusanov
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Nathanial Clark
- Center for Computational Molecular Biology, Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912, USA
| | - Negar Goodarzi
- Mechanisms and Regulation of Splicing Research Group, The Institute of Cancer Research, London, UK
| | - Nicolas Schmidt
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Hua Sun
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Reilly A Sample
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joshua R Brickner
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Drew McDonald
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Miaw-Sheue Tsai
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matthew J Walter
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David F Wozniak
- Department of Psychiatry, Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Alex S Holehouse
- Department of Biochemistry & Molecular Biophysics, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA; Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Vladimir Pena
- Mechanisms and Regulation of Splicing Research Group, The Institute of Cancer Research, London, UK
| | - John A Tainer
- Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - William G Fairbrother
- Center for Computational Molecular Biology, Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912, USA; Hassenfeld Child Health Innovation Institute of Brown University, Providence, RI 02912, USA.
| | - Nima Mosammaparast
- Department of Pathology & Immunology, Center for Genome Integrity, Washington University School of Medicine, St. Louis, MO 63110, USA.
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10
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Choi Y, Lee HH, Park J, Kim S, Choi S, Moon H, Shin J, Kim JE, Choi GJ, Seo YS, Son H. Intron turnover is essential to the development and pathogenicity of the plant pathogenic fungus Fusarium graminearum. Commun Biol 2022; 5:1129. [PMID: 36289323 PMCID: PMC9606315 DOI: 10.1038/s42003-022-04111-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022] Open
Abstract
Intron lariats excised during the splicing process are rapidly degraded by RNA lariat debranching enzyme (Dbr1) and several exonucleases. Rapid turnover of lariat RNA is essential to cellular RNA homeostasis. However, the functions of Dbr1 have not been investigated in filamentous fungi. Here, we characterized the molecular functions of Dbr1 in Fusarium graminearum, a major fungal plant pathogen. Deletion of FgDBR1 resulted in pleiotropic defects in hyphal growth, conidiation, sexual reproduction, and virulence. Through transcriptome analysis, we revealed that the deletion mutant exhibited global accumulation of intron lariats and upregulation of ribosome-related genes. Excessive accumulation of lariat RNA led to reduced overall protein synthesis, causing various phenotypic defects in the absence of FgDBR1. The results of this study demonstrate that a compromised intron turnover process affects development and pathogenesis in this fungus and that Dbr1 function is critical to plant pathogenic fungi. RNA lariat debranching enzyme Dbr1 is required for intron turnover in the fungal plant pathogen <i>Fusarium graminearum <i > , and accumulation of lariat RNA affects its development and pathogenesis.
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Affiliation(s)
- Yejin Choi
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Hyun-Hee Lee
- grid.262229.f0000 0001 0719 8572Department of Integrated Biological Science, Pusan National University, Busan, 46247 Republic of Korea
| | - Jiyeun Park
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Sieun Kim
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Soyoung Choi
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Heeji Moon
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jiyoung Shin
- grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jung-Eun Kim
- grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Gyung Ja Choi
- grid.29869.3c0000 0001 2296 8192Therapeutic & Biotechnology Division, Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, 34114 Republic of Korea
| | - Young-Su Seo
- grid.262229.f0000 0001 0719 8572Department of Integrated Biological Science, Pusan National University, Busan, 46247 Republic of Korea
| | - Hokyoung Son
- grid.31501.360000 0004 0470 5905Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea ,grid.31501.360000 0004 0470 5905Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
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11
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Wu C, Wang X, Zhen W, Nie Y, Li Y, Yuan P, Liu Q, Guo S, Shen Z, Zheng B, Hu Z. SICKLE modulates lateral root development by promoting degradation of lariat intronic RNA. PLANT PHYSIOLOGY 2022; 190:548-561. [PMID: 35788403 PMCID: PMC9434198 DOI: 10.1093/plphys/kiac301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Plant lateral roots (LRs) play vital roles in anchorage and uptake of water and nutrients. Here, we reveal that degradation of lariat intronic RNAs (lariRNAs) modulated by SICKLE (SIC) is required for LR development in Arabidopsis (Arabidopsis thaliana). Loss of SIC results in hyper-accumulation of lariRNAs and restricts the outgrowth of LR primordia, thereby reducing the number of emerged LRs. Decreasing accumulation of lariRNAs by over-expressing RNA debranching enzyme 1 (DBR1), a rate-limiting enzyme of lariRNA decay, restored LR defects in SIC-deficient plants. Mechanistically, SIC interacts with DBR1 and facilitates its nuclear accumulation, which is achieved through two functionally redundant regions (SIC1-244 and SIC252-319) for nuclear localization. Of the remaining amino acids in this region, six (SIC245-251) comprise a DBR1-interacting region while two (SICM246 and SICW251) are essential for DBR1-SIC interaction. Reducing lariRNAs restored microRNA (miRNA) levels and LR development in lariRNA hyper-accumulating plants, suggesting that these well-known regulators of LR development mainly function downstream of lariRNAs. Taken together, we propose that SIC acts as an enhancer of DBR1 nuclear accumulation by driving nuclear localization through direct interaction, thereby promoting lariRNA decay to fine-tune miRNA biogenesis and modulating LR development.
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Affiliation(s)
- Chengyun Wu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
- Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
- Sanya Institute of Henan University, Sanya 572025, China
| | - Xiaoqing Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Weibo Zhen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yaqing Nie
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yan Li
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Penglai Yuan
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Qiaoqiao Liu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Siyi Guo
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Zhenguo Shen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
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12
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Bhattarai-Kline S, Lear SK, Fishman CB, Lopez SC, Lockshin ER, Schubert MG, Nivala J, Church GM, Shipman SL. Recording gene expression order in DNA by CRISPR addition of retron barcodes. Nature 2022; 608:217-225. [PMID: 35896746 PMCID: PMC9357182 DOI: 10.1038/s41586-022-04994-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 06/17/2022] [Indexed: 02/03/2023]
Abstract
Biological processes depend on the differential expression of genes over time, but methods to make physical recordings of these processes are limited. Here we report a molecular system for making time-ordered recordings of transcriptional events into living genomes. We do this through engineered RNA barcodes, based on prokaryotic retrons1, that are reverse transcribed into DNA and integrated into the genome using the CRISPR-Cas system2. The unidirectional integration of barcodes by CRISPR integrases enables reconstruction of transcriptional event timing based on a physical record through simple, logical rules rather than relying on pretrained classifiers or post hoc inferential methods. For disambiguation in the field, we will refer to this system as a Retro-Cascorder.
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Affiliation(s)
| | - Sierra K Lear
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Graduate Program in Bioengineering, University of California, San Francisco and Berkeley, San Francisco, CA, USA
| | - Chloe B Fishman
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
| | - Santiago C Lopez
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Graduate Program in Bioengineering, University of California, San Francisco and Berkeley, San Francisco, CA, USA
| | - Elana R Lockshin
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
| | - Max G Schubert
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Jeff Nivala
- Paul G. Allen School of Computer Science & Engineering, University of Washington, Seattle, WA, USA
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Seth L Shipman
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA.
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA.
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13
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Clark NE, Katolik A, Taggart AJ, Buerer L, Holloway SP, Miller N, Phillips JD, Farrell CP, Damha MJ, Fairbrother WG. Metal content and kinetic properties of yeast RNA lariat debranching enzyme Dbr1. RNA (NEW YORK, N.Y.) 2022; 28:927-936. [PMID: 35459748 PMCID: PMC9202583 DOI: 10.1261/rna.079159.122] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
In eukaryotic cells, intron lariats produced by the spliceosome contain a 2'5' phosphodiester linkage. The RNA lariat debranching enzyme, Dbr1, is the only enzyme known to hydrolyze this bond. Dbr1 is a member of the metallophosphoesterase (MPE) family of enzymes, and recent X-ray crystal structures and biochemistry data demonstrate that Dbr1 from Entamoeba histolytica uses combinations of Mn2+, Zn2+, and Fe2+ as enzymatic cofactors. Here, we examine the kinetic properties and metal dependence of the Dbr1 homolog from Saccharomyces cerevisiae (yDbr1). Elemental analysis measured stoichiometric quantities of Fe and Zn in yDbr1 purified following heterologous expression E. coli We analyzed the ability of Fe2+, Zn2+, and Mn2+ to reconstitute activity in metal-free apoenzyme. Purified yDbr1 was highly active, turning over substrate at 5.6 sec-1, and apo-yDbr1 reconstituted with Fe2+ was the most active species, turning over at 9.2 sec-1 We treated human lymphoblastoid cells with the iron-chelator deferoxamine and measured a twofold increase in cellular lariats. These data suggest that Fe is an important biological cofactor for Dbr1 enzymes.
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Affiliation(s)
- Nathaniel E Clark
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
| | - Adam Katolik
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Allison J Taggart
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, USA
| | - Luke Buerer
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
| | - Stephen P Holloway
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Nathaniel Miller
- Department of Geological Sciences, University of Texas Austin, Austin, Texas 78712, USA
| | - John D Phillips
- Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
| | - Colin P Farrell
- Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
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14
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Yu L, Majerciak V, Zheng ZM. HPV16 and HPV18 Genome Structure, Expression, and Post-Transcriptional Regulation. Int J Mol Sci 2022; 23:ijms23094943. [PMID: 35563334 PMCID: PMC9105396 DOI: 10.3390/ijms23094943] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 12/18/2022] Open
Abstract
Human papillomaviruses (HPV) are a group of small non-enveloped DNA viruses whose infection causes benign tumors or cancers. HPV16 and HPV18, the two most common high-risk HPVs, are responsible for ~70% of all HPV-related cervical cancers and head and neck cancers. The expression of the HPV genome is highly dependent on cell differentiation and is strictly regulated at the transcriptional and post-transcriptional levels. Both HPV early and late transcripts differentially expressed in the infected cells are intron-containing bicistronic or polycistronic RNAs bearing more than one open reading frame (ORF), because of usage of alternative viral promoters and two alternative viral RNA polyadenylation signals. Papillomaviruses proficiently engage alternative RNA splicing to express individual ORFs from the bicistronic or polycistronic RNA transcripts. In this review, we discuss the genome structures and the updated transcription maps of HPV16 and HPV18, and the latest research advances in understanding RNA cis-elements, intron branch point sequences, and RNA-binding proteins in the regulation of viral RNA processing. Moreover, we briefly discuss the epigenetic modifications, including DNA methylation and possible APOBEC-mediated genome editing in HPV infections and carcinogenesis.
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15
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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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16
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Xu X, Yang X, Liu X, Bi Y, Kong P, Wang Y, Cheng X, Xi Y. The Role of DBR1 as a Candidate Prognosis Biomarker in Esophageal Squamous Cell Carcinoma. Technol Cancer Res Treat 2022; 21:15330338221083105. [PMID: 35244467 PMCID: PMC8902023 DOI: 10.1177/15330338221083105] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 01/20/2022] [Accepted: 02/02/2022] [Indexed: 11/16/2022] Open
Abstract
Aims: Esophageal squamous cell carcinoma (ESCC) is one of the most prevalent malignancies with unfavorable clinical outcomes and limited therapeutic methods. As a key enzyme in RNA metabolism, debranching RNA Lariats 1 (DBR1) is involved in intron turnover and biogenesis of noncoding RNA. Although cancer cells often show disorder of nucleic acid metabolism, it is unclear whether DBR1 has any effect on the carcinogenesis and progression of ESCC. Methods: Here we detected DBR1 expression in 112 ESCC samples by immunohistochemistry and analyzed its correlation with clinical parameters and survival. Results: DBR1 is mainly located in the nucleus of ESCC tissue. And DBR1 was associated with several malignant clinical features in patients, including tumor location (χ2 = 9.687, P = .021), pathologic T stage (χ2 = 5.771, P = .016), lymph node metastasis (χ2 = 8.215, P = .004) and N classification (χ2 = 10.066, P = .018). Moreover, Kaplan-Meier analysis showed that ESCC patients harboring lower DBR1 expression had a worse prognosis in comparison with those with higher DBR1 expression (P = .005). Univariate and multivariate Cox proportional hazards regression analyses indicated that decreased DBR1 might act as an independent predictor of poor prognosis for ESCC patients. Conclusion: Abnormal RNA metabolism might play a critical role in promoting the progression of ESCC, and DBR1 may be a promising potential biomarker for predicting the prognosis of ESCC patients.
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Affiliation(s)
- Xiaoqin Xu
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
- Shanxi Cancer Hospital, Taiyuan, Shanxi, People’s Republic of China
| | - Xin Yang
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
| | - Xue Liu
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
| | - Yanghui Bi
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
| | - Pengzhou Kong
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
| | - Yanqiang Wang
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
| | - Xiaolong Cheng
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China
| | - Yanfeng Xi
- Shanxi Cancer Hospital, Taiyuan, Shanxi, People’s Republic of China
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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: 14] [Impact Index Per Article: 4.7] [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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18
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Constitutive and latent immune mechanisms exert 'silent' control of virus infections in the central nervous system. Curr Opin Immunol 2021; 72:158-166. [PMID: 34062364 DOI: 10.1016/j.coi.2021.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 12/14/2022]
Abstract
Viral infections in the central nervous system (CNS) can lead to severe disease manifestations often mediated by a combination of viral cytopathic effects and immunopathology. Moreover, neuronal tissue and brain activities are highly sensitive to excessive inflammation that disturb homeostasis. Immune responses to virus infections in the CNS should therefore be tightly balanced and limited in magnitude and duration to avoid immunopathology and tissue damage. Recent data from genetic studies of patients with viral infections in the CNS as well as experimental cell and animal models have provided evidence of non-redundant roles for constitutive and latent immune mechanisms, which mediate a first line of antiviral control without significantly triggering inflammatory activities. Collectively, accumulating data suggest the existence of a layer of immune mechanisms in the CNS exerting immediate control of infection, hence buffering the need for activation of more potent immune reactions with inherent potential to induce immunopathology and disease.
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Villa T, Barucco M, Martin-Niclos MJ, Jacquier A, Libri D. Degradation of Non-coding RNAs Promotes Recycling of Termination Factors at Sites of Transcription. Cell Rep 2021; 32:107942. [PMID: 32698007 DOI: 10.1016/j.celrep.2020.107942] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 05/08/2020] [Accepted: 06/30/2020] [Indexed: 12/27/2022] Open
Abstract
A large share of the non-coding transcriptome in yeast is controlled by the Nrd1-Nab3-Sen1 (NNS) complex, which promotes transcription termination of non-coding RNA (ncRNA) genes, and by the nuclear exosome, which limits the steady-state levels of the transcripts produced. How unconstrained ncRNA levels affect RNA metabolism and gene expression are long-standing and important questions. Here, we show that degradation of ncRNAs by the exosome is required for freeing Nrd1 and Nab3 from the released transcript after termination. In exosome mutants, these factors are sequestered by ncRNAs and cannot be efficiently recycled to sites of transcription, inducing termination defects at NNS targets. ncRNA-dependent, genome-wide termination defects can be recapitulated by the expression of a degradation-resistant, circular RNA containing a natural NNS target in exosome-proficient cells. Our results have important implications for the mechanism of termination, the general impact of ncRNAs abundance, and the importance of nuclear ncRNA degradation.
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Affiliation(s)
- Tommaso Villa
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France.
| | - Mara Barucco
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France
| | | | - Alain Jacquier
- Institut Pasteur, Centre National de la Recherche Scientifique, UMR3525 Paris, France
| | - Domenico Libri
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France.
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20
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Menees TM. Saccharomyces cerevisiae RNA lariat debranching enzyme, Dbr1p, is required for completion of reverse transcription by the retrovirus-like element Ty1 and cleaves branched Ty1 RNAs. Mol Genet Genomics 2021; 296:409-422. [PMID: 33464395 DOI: 10.1007/s00438-020-01753-y] [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: 08/31/2020] [Accepted: 12/14/2020] [Indexed: 11/25/2022]
Abstract
RNA debranching enzymes are 2'-5' phosphodiesterases found in all eukaryotes. Their main role is cleavage of intron RNA lariat branch points, promoting RNA turnover via exonucleases. Consistent with this role, cells with reduced RNA debranching enzyme activity accumulate intron RNA lariats. The Saccharomyces cerevisiae RNA debranching enzyme Dbr1p is also a host factor for the yeast long terminal repeat (LTR) retrotransposon Ty1, a model for many aspects of retroviral replication. Fittingly, the human RNA debranching enzyme Dbr1 is a host factor for the human immunodeficiency virus, HIV-1. The yeast and human RNA debranching enzymes act at the reverse transcription stages for Ty1 and HIV-1, respectively. Although efficient production of full-length Ty1 cDNA requires Dbr1p, the findings reported here indicate that production of the earliest distinct cDNA product, minus strand strong stop DNA (-sssDNA), is equivalent in wild type and dbr1∆ mutant cells. Several branched Ty1 RNAs are shown to accumulate in dbr1∆ cells during retrotransposition. These data are consistent with creation of Ty1 RNA branches prior to Ty1 reverse transcription and their removal by Dbr1p to allow efficient extension of early cDNA products. The data support the possibility that RNA branch formation and cleavage play broadly shared, but unknown roles in retroviral and LTR retrotransposon reverse transcription.
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Affiliation(s)
- Thomas M Menees
- School of Biological and Chemical Sciences, University of Missouri-Kansas City, Kansas City, MO, USA.
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21
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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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22
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Abstract
Host cell factors are integral to viral replication. Human immunodeficiency virus 1 (HIV-1), the retroviral agent of acquired immune deficiency syndrome, requires several host factors for reverse transcription of the viral genomic RNA (gRNA) into DNA shortly after viral entry. One of these host factors is the RNA lariat debranching enzyme (Dbr1), which cleaves the 2'-5' bond of branched and lariat RNAs. A recent study has revealed that Dbr1 cleaves HIV-1 gRNA lariats that form early after viral entry. Without Dbr1 activity, HIV-1 reverse transcription stalls, consistent with blockage of viral reverse transcriptase at gRNA branch points. These findings echo an earlier study with the long-terminal-repeat retrotransposon of Saccharomyces cerevisiae, Ty1, which is a retrovirus model. Currently, branching and debranching of viral gRNA are not widely recognized as features of HIV-1 replication, and the role of a gRNA lariat is not known. Future studies will determine whether these gRNA dynamics represent fundamental features of retroviral biology and whether they occur for other positive-sense RNA viruses.
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Affiliation(s)
- Thomas M Menees
- School of Biological and Chemical Sciences, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA;
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24
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Jin J, He X, Silva E. Stable intronic sequence RNAs (sisRNAs) are selected regions in introns with distinct properties. BMC Genomics 2020; 21:287. [PMID: 32264855 PMCID: PMC7137253 DOI: 10.1186/s12864-020-6687-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 03/18/2020] [Indexed: 12/31/2022] Open
Abstract
Background Stable introns and intronic fragments make up the largest population of RNA in the oocyte nucleus of the frog Xenopus tropicalis. These stable intronic sequence RNAs (sisRNAs) persist through the onset of zygotic transcription when synchronous cell division has ended, and the developing embryo consists of approximately 8000 cells. Despite their abundance, the sequence properties and biological function of sisRNAs are just beginning to be understood. Results To characterize this population of non-coding RNA, we identified all of the sisRNAs in the X. tropicalis oocyte nucleus using published high-throughput RNA sequencing data. Our analysis revealed that sisRNAs, have an average length of ~ 360 nt, are widely expressed from genes with multiple introns, and are derived from specific regions of introns that are GC and TG rich, while CpG poor. They are enriched in introns at both ends of transcripts but preferentially at the 3′ end. The consensus binding sites of specific transcription factors such as Stat3 are enriched in sisRNAs, suggesting an association between sisRNAs and transcription factors involved in early development. Evolutionary conservation analysis of sisRNA sequences in seven vertebrate genomes indicates that sisRNAs are as conserved as other parts of introns, but much less conserved than exons. Conclusion In total, our results indicate sisRNAs are selected intron regions with distinct properties and may play a role in gene expression regulation.
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Affiliation(s)
- Jing Jin
- Department of Physiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.,Department of Biology, Georgetown University, 37th and O Sts, NW, Washington DC, 20057, USA
| | - Ximiao He
- Department of Physiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
| | - Elena Silva
- Department of Biology, Georgetown University, 37th and O Sts, NW, Washington DC, 20057, USA.
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25
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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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26
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Human inborn errors of immunity to herpes viruses. Curr Opin Immunol 2020; 62:106-122. [PMID: 32014647 DOI: 10.1016/j.coi.2020.01.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/16/2019] [Accepted: 01/07/2020] [Indexed: 12/16/2022]
Abstract
Infections with any of the nine human herpes viruses (HHV) can be asymptomatic or life-threatening. The study of patients with severe diseases caused by HHVs, in the absence of overt acquired immunodeficiency, has led to the discovery or diagnosis of various inborn errors of immunity. The related inborn errors of adaptive immunity disrupt α/β T-cell rather than B-cell immunity. Affected patients typically develop HHV infections in the context of other infectious diseases. However, this is not always the case, as illustrated by inborn errors of SAP-dependent T-cell immunity to EBV-infected B cells. The related inborn errors of innate immunity disrupt leukocytes other than T and B cells, non-hematopoietic cells, or both. Patients typically develop only a single type of infection due to HHV, although, again, this is not always the case, as illustrated by inborn errors of TLR3 immunity resulting in HSV1 encephalitis in some patients and influenza pneumonitis in others. Most severe HHV infections in otherwise healthy patients remains unexplained. The forward human genetic dissection of isolated and syndromic HHV-driven illnesses will establish the molecular and cellular basis of protective immunity to HHVs, paving the way for novel diagnosis and management strategies.
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Abstract
PURPOSE OF REVIEW Studying primary immunodeficiencies (PIDs) provides insights into human antiviral immunity in the natural infectious environment. This review describes new PIDs with genetic defects that impair innate antiviral responses. RECENT FINDINGS New genetic defects in the interferon (IFN) signaling pathway include IFNAR1 deficiency, which causes uncontrolled infections with measles-mumps-rubella or yellow fever vaccines, and possibly also cytomegalovirus (CMV); and IRF9 deficiency, which results in influenza virus susceptibility. Genetic defects in several pattern recognition receptors include MDA5 deficiency, which impairs viral RNA sensing and confers human rhinovirus susceptibility; RNA polymerase III haploinsufficiency, which impairs sensing of A:T-rich virus DNA and confers VZV susceptibility; and TLR3 deficiency, which causes HSV-1 encephalitis (HSE) or influenza virus pneumonitis. Defects in RNA metabolism, such as that caused by Debranching enzyme 1 deficiency, can cause virus meningoencephalitis. Finally, defects in host restriction factors for virus replication, such as in CIB1 deficiency, contribute to uncontrolled β-HPV infections. SUMMARY Several new PIDs highlight the role of type I/III IFN signaling pathway, virus sensors, and host virus restriction factors in human antiviral immunity.
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Affiliation(s)
- Huie Jing
- Human Immunological Diseases Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Helen C. Su
- Human Immunological Diseases Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health
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28
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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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Královicová J, Ševcíková I, Stejskalová E, Obuca M, Hiller M, Stanek D, Vorechovský I. PUF60-activated exons uncover altered 3' splice-site selection by germline missense mutations in a single RRM. Nucleic Acids Res 2019; 46:6166-6187. [PMID: 29788428 PMCID: PMC6093180 DOI: 10.1093/nar/gky389] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 05/01/2018] [Indexed: 12/27/2022] Open
Abstract
PUF60 is a splicing factor that binds uridine (U)-rich tracts and facilitates association of the U2 small nuclear ribonucleoprotein with primary transcripts. PUF60 deficiency (PD) causes a developmental delay coupled with intellectual disability and spinal, cardiac, ocular and renal defects, but PD pathogenesis is not understood. Using RNA-Seq, we identify human PUF60-regulated exons and show that PUF60 preferentially acts as their activator. PUF60-activated internal exons are enriched for Us upstream of their 3′ splice sites (3′ss), are preceded by longer AG dinucleotide exclusion zones and more distant branch sites, with a higher probability of unpaired interactions across a typical branch site location as compared to control exons. In contrast, PUF60-repressed exons show U-depletion with lower estimates of RNA single-strandedness. We also describe PUF60-regulated, alternatively spliced isoforms encoding other U-bound splicing factors, including PUF60 partners, suggesting that they are co-regulated in the cell, and identify PUF60-regulated exons derived from transposed elements. PD-associated amino-acid substitutions, even within a single RNA recognition motif (RRM), altered selection of competing 3′ss and branch points of a PUF60-dependent exon and the 3′ss choice was also influenced by alternative splicing of PUF60. Finally, we propose that differential distribution of RNA processing steps detected in cells lacking PUF60 and the PUF60-paralog RBM39 is due to the RBM39 RS domain interactions. Together, these results provide new insights into regulation of exon usage by the 3′ss organization and reveal that germline mutation heterogeneity in RRMs can enhance phenotypic variability at the level of splice-site and branch-site selection.
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Affiliation(s)
- Jana Královicová
- University of Southampton Faculty of Medicine, Southampton SO16 6YD, UK.,Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Ivana Ševcíková
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Eva Stejskalová
- Czech Academy of Sciences, Institute of Molecular Genetics, 142 20 Prague, Czech Republic
| | - Mina Obuca
- Czech Academy of Sciences, Institute of Molecular Genetics, 142 20 Prague, Czech Republic
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics and Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - David Stanek
- Czech Academy of Sciences, Institute of Molecular Genetics, 142 20 Prague, Czech Republic
| | - Igor Vorechovský
- University of Southampton Faculty of Medicine, Southampton SO16 6YD, UK
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30
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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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31
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Mendoza-Figueroa MS, Alfonso-Maqueira EE, Vélez C, Azuara-Liceaga EI, Zárate S, Villegas-Sepúlveda N, Saucedo-Cárdenas O, Valdés J. Postsplicing-Derived Full-Length Intron Circles in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2018; 8:255. [PMID: 30123775 PMCID: PMC6085484 DOI: 10.3389/fcimb.2018.00255] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
Noncoding circular RNAs are widespread in the tree of life. Particularly, intron-containing circular RNAs which apparently upregulate their parental gene expression. Entamoeba histolytica, the causative agent of dysentery and liver abscesses in humans, codes for several noncoding RNAs, including circular ribosomal RNAs, but no intron containing circular RNAs have been described to date. Divergent RT-PCR and diverse molecular approaches, allowed us to detect bona fide full-length intronic circular RNA (flicRNA) molecules. Self-splicing reactions, RNA polymerase II inhibition with Actinomycin D, and second step of splicing-inhibition with boric acid showed that the production of flicRX13 (one of the flicRNAs found in this work, and our test model) depends on mRNA synthesis and pre-mRNA processing instead of self-splicing. To explore the cues and factors involved in flicRX13 biogenesis in vivo, splicing assays were carried out in amoeba transformants where splicing factors and Dbr1 (intron lariat debranching enzyme 1) were silenced or overexpressed, or where Rabx13 wild-type and mutant 5'ss (splice site) and branch site minigene constructs were overexpressed. Whereas SF1 (splicing factor 1) is not involved, the U2 auxiliary splicing factor, Dbr1, and the GU-rich 5'ss are involved in postsplicing flicRX13 biogenesis, probably by Dbr1 stalling, in a similar fashion to the formation of ciRNAs (circular intronic RNAs), but with distinctive 5'-3'ss ligation points. Different from the reported functions of ciRNAs, the 5'ss GU-rich element of flicRX13 possibly interacts with transcription machinery to silence its own gene in cis. Furthermore, introns of E. histolytica virulence-related genes are also processed as flicRNAs.
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Affiliation(s)
- María S Mendoza-Figueroa
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Eddy E Alfonso-Maqueira
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cristina Vélez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Elisa I Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de Mexico, Mexico City, Mexico
| | - Selene Zárate
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de Mexico, Mexico City, Mexico
| | - Nicolás Villegas-Sepúlveda
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Odila Saucedo-Cárdenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico.,División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Jesús Valdés
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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32
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Abstract
De novo genes are very important for evolutionary innovation. However, how these genes originate and spread remains largely unknown. To better understand this, we rigorously searched for de novo genes in Saccharomyces cerevisiae S288C and examined their spread and fixation in the population. Here, we identified 84 de novo genes in S. cerevisiae S288C since the divergence with their sister groups. Transcriptome and ribosome profiling data revealed at least 8 (10%) and 28 (33%) de novo genes being expressed and translated only under specific conditions, respectively. DNA microarray data, based on 2-fold change, showed that 87% of the de novo genes are regulated during various biological processes, such as nutrient utilization and sporulation. Our comparative and evolutionary analyses further revealed that some factors, including single nucleotide polymorphism (SNP)/indel mutation, high GC content, and DNA shuffling, contribute to the birth of de novo genes, while domestication and natural selection drive the spread and fixation of these genes. Finally, we also provide evidence suggesting the possible parallel origin of a de novo gene between S. cerevisiae and Saccharomyces paradoxus. Together, our study provides several new insights into the origin and spread of de novo genes. Emergence of de novo genes has occurred in many lineages during evolution, but the birth, spread, and function of these genes remain unresolved. Here we have searched for de novo genes from Saccharomyces cerevisiae S288C using rigorous methods, which reduced the effects of bad annotation and genomic gaps on the identification of de novo genes. Through this analysis, we have found 84 new genes originating de novo from previously noncoding regions, 87% of which are very likely involved in various biological processes. We noticed that 10% and 33% of de novo genes were only expressed and translated under specific conditions, therefore, verification of de novo genes through transcriptome and ribosome profiling, especially from limited expression data, may underestimate the number of bona fide new genes. We further show that SNP/indel mutation, high GC content, and DNA shuffling could be involved in the birth of de novo genes, while domestication and natural selection drive the spread and fixation of these genes. Finally, we provide evidence suggesting the possible parallel origin of a new gene.
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33
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Valdés J, Ortuño-Pineda C, Saucedo-Cárdenas O, Mendoza-Figueroa MS. Unexplored Molecular Features of the Entamoeba histolytica RNA Lariat Debranching Enzyme Dbr 1 Expression Profile. Front Cell Infect Microbiol 2018; 8:228. [PMID: 30023353 PMCID: PMC6039765 DOI: 10.3389/fcimb.2018.00228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 06/18/2018] [Indexed: 11/25/2022] Open
Abstract
The RNA lariat debranching enzyme (Dbr1) has different functions in RNA metabolism, such as hydrolyzing the 2′-5′ linkage in intron lariats, positively influencing Ty1 and HIV-1 retrotransposition, and modulating snRNP recycling during splicing reactions. It seems that Dbr1 is one of the major players in RNA turnover. It is remarkable that of all the studies carried out to date with Dbr1, to our knowledge, none of them have evaluated the expression profile of the endogenous Dbr1 gene. In this work, we describe, for the first time, that Entamoeba histolytica EhDbr1 mRNA has a very short half-life (less than 30 min) and encodes a very stable protein that is present until trophozoite cultures die. We also show that the EhDbr1 protein is present in the nuclear periphery on the cytoplasmic basal side, contrary to the localization of human Dbr1. Comparing these results with previous hypotheses and with results from different organisms suggests that Dbr1 gene expression is finely tuned and conserved across eukaryotes. Experiments describing the aspects of Dbr1 gene expression and Dbr1 mRNA turnover as well as other functions of the protein need to be performed. Particularly, a special emphasis is needed on the protozoan parasite E. histolytica, the causative agent of amoebiasis, since even though it is a unicellular organism, it is an intron-rich eukaryote whose intron lariats seem to be open to avoid intron lariat accumulation and to process them in non-coding RNAs that might be involved in its virulence.
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Affiliation(s)
- Jesús Valdés
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Carlos Ortuño-Pineda
- Unidad Académica de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Mexico
| | - Odila Saucedo-Cárdenas
- Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico.,División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - María S Mendoza-Figueroa
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.,Departamento de Atención a la Salud, Universidad Autónoma Metropolitana-Xochimilco, Mexico City, Mexico
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34
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Chen W, Moore J, Ozadam H, Shulha HP, Rhind N, Weng Z, Moore MJ. Transcriptome-wide Interrogation of the Functional Intronome by Spliceosome Profiling. Cell 2018; 173:1031-1044.e13. [PMID: 29727662 PMCID: PMC6090549 DOI: 10.1016/j.cell.2018.03.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/09/2018] [Accepted: 03/23/2018] [Indexed: 12/31/2022]
Abstract
Full understanding of eukaryotic transcriptomes and how they respond to different conditions requires deep knowledge of all sites of intron excision. Although RNA sequencing (RNA-seq) provides much of this information, the low abundance of many spliced transcripts (often due to their rapid cytoplasmic decay) limits the ability of RNA-seq alone to reveal the full repertoire of spliced species. Here, we present "spliceosome profiling," a strategy based on deep sequencing of RNAs co-purifying with late-stage spliceosomes. Spliceosome profiling allows for unambiguous mapping of intron ends to single-nucleotide resolution and branchpoint identification at unprecedented depths. Our data reveal hundreds of new introns in S. pombe and numerous others that were previously misannotated. By providing a means to directly interrogate sites of spliceosome assembly and catalysis genome-wide, spliceosome profiling promises to transform our understanding of RNA processing in the nucleus, much as ribosome profiling has transformed our understanding mRNA translation in the cytoplasm.
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Affiliation(s)
- Weijun Chen
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jill Moore
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hakan Ozadam
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hennady P Shulha
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Nicholas Rhind
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Zhiping Weng
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Melissa J Moore
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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35
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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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36
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Carrocci TJ, Lohe L, Ashton MJ, Höbartner C, Hoskins AA. Debranchase-resistant labeling of RNA using the 10DM24 deoxyribozyme and fluorescent modified nucleotides. Chem Commun (Camb) 2017; 53:11992-11995. [PMID: 28984884 PMCID: PMC5668183 DOI: 10.1039/c7cc06703h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The 10DM24 deoxyribozyme can site-specifically label RNAs with fluorophore-GTP conjugates; however, the 2',5'-branched RNA linkage is readily cleaved by debranchase. To prevent loss of labels upon cleavage, we synthesized phosphorothioate-modified, fluorescent GTP derivatives and elaborated conditions for their incorporation by 10DM24. RNAs labeled with fluorescent derivatives of Sp-GTPS were found to be resistant to debranchase.
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Affiliation(s)
- Tucker J Carrocci
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Dr., Madison, WI 53706, USA.
| | - Lea Lohe
- Institute for Organic and Biomolecular Chemistry, Georg-August-University Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
| | - Matthew J Ashton
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Dr., Madison, WI 53706, USA.
| | - Claudia Höbartner
- Institute for Organic and Biomolecular Chemistry, Georg-August-University Göttingen, Tammannstr. 2, 37077 Göttingen, Germany and Institute for Organic Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Dr., Madison, WI 53706, USA.
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37
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Conformational Changes in the 5' End of the HIV-1 Genome Dependent on the Debranching Enzyme DBR1 during Early Stages of Infection. J Virol 2017; 91:JVI.01377-17. [PMID: 28931690 DOI: 10.1128/jvi.01377-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 09/18/2017] [Indexed: 11/20/2022] Open
Abstract
Previous studies in our laboratory showed that the RNA debranching enzyme (DBR1) is not required for early steps in HIV cDNA formation but is necessary for synthesis of intermediate and late cDNA products. To further characterize this effect, we evaluated the topology of the 5' end of the HIV-1 RNA genome during early infection with and without inhibition of DBR1 synthesis. Cells were transfected with DBR1 short hairpin RNA (shRNA) followed 48 h later by infection with an HIV-1-derived vector containing an RNase H-deficient reverse transcriptase (RT). RNA was isolated at several times postinfection and treated with various RNA-modifying enzymes prior to rapid amplification of 5' cDNA ends (5' RACE) for HIV-1 RNA and quantitative reverse transcriptase PCR (qRT-PCR). In infected cells, DBR1 knockdown inhibited detection of free HIV-1 RNA 5' ends at all time points. The difference in detection of free HIV-1 RNA 5' ends in infected DBR1 knockdown versus control cells was eliminated by in vitro incubation of infected cell RNAs with yeast or human DBR1 enzyme prior to 5' RACE and qRT-PCR. This was dependent on the 2'-5' phosphatase activity of DBR1, since it did not occur when we used the catalytically inactive DBR1(N85A) mutant. Finally, HIV-1 RNA from infected DBR1 knockdown cells was resistant to RNase R that degrades linear RNAs but not RNAs in circular or lariat-like conformations. These results provide evidence for formation of a lariat-like structure involving the 5' end of HIV-1 RNA during an early step in infection and the involvement of DBR1 in resolving it.IMPORTANCE Our findings support a new view of the early steps in HIV genome replication. We show that the HIV genomic RNA is rapidly decapped and forms a lariat-like structure after entering a cell. The lariat-like structure is subsequently resolved by the cellular enzyme DBR1, leaving a 5' phosphate. This pathway is similar to the formation and resolution of pre-mRNA intron lariats and therefore suggests that similar mechanisms may be used by HIV. Our work therefore opens a new area of investigation in HIV replication and may ultimately uncover new targets for inhibiting HIV replication and for preventing the development of AIDS.
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Döring J, Hurek T. Arm-specific cleavage and mutation during reverse transcription of 2΄,5΄-branched RNA by Moloney murine leukemia virus reverse transcriptase. Nucleic Acids Res 2017; 45:3967-3984. [PMID: 28160599 PMCID: PMC5399748 DOI: 10.1093/nar/gkx073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 01/30/2017] [Indexed: 11/14/2022] Open
Abstract
Branchpoint nucleotides of intron lariats induce pausing of DNA synthesis by reverse transcriptases (RTs), but it is not known yet how they direct RT RNase H activity on branched RNA (bRNA). Here, we report the effects of the two arms of bRNA on branchpoint-directed RNA cleavage and mutation produced by Moloney murine leukemia virus (M-MLV) RT during DNA polymerization. We constructed a long-chained bRNA template by splinted-ligation. The bRNA oligonucleotide is chimeric and contains DNA to identify RNA cleavage products by probe hybridization. Unique sequences surrounding the branchpoint facilitate monitoring of bRNA purification by terminal-restriction fragment length polymorphism analysis. We evaluate the M-MLV RT-generated cleavage and mutational patterns. We find that cleavage of bRNA and misprocessing of the branched nucleotide proceed arm-specifically. Bypass of the branchpoint from the 2΄-arm causes single-mismatch errors, whereas bypass from the 3΄-arm leads to deletion mutations. The non-template arm is cleaved when reverse transcription is primed from the 3΄-arm but not from the 2΄-arm. This suggests that RTs flip ∼180° at branchpoints and RNases H cleave the non-template arm depending on its accessibility. Our observed interplay between M-MLV RT and bRNA would be compatible with a bRNA-mediated control of retroviral and related retrotransposon replication.
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Affiliation(s)
- Jessica Döring
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), University of Bremen, PO Box 330440, D-28334 Bremen, Germany
| | - Thomas Hurek
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), University of Bremen, PO Box 330440, D-28334 Bremen, Germany
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Biology and Pathobiology of TDP-43 and Emergent Therapeutic Strategies. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024554. [PMID: 27920024 DOI: 10.1101/cshperspect.a024554] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cytoplasmic TDP-43 mislocalization and aggregation is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 is an RNA-binding protein (RBP) with a prion-like domain (PrLD) that promotes TDP-43 misfolding. PrLDs possess compositional similarity to canonical prion domains of various yeast proteins, including Sup35. Strikingly, disease-causing TDP-43 mutations reside almost exclusively in the PrLD and can enhance TDP-43 misfolding and toxicity. Another ∼70 human RBPs harbor PrLDs, including FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2, which have surfaced in the etiology of neurodegenerative diseases. Importantly, PrLDs enable RBP function and mediate phase transitions that partition functional ribonucleoprotein compartments. This PrLD activity, however, renders RBPs prone to populating deleterious oligomers or self-templating fibrils that might spread disease, and disease-linked PrLD mutations can exacerbate this risk. Several strategies have emerged to counter TDP-43 proteinopathies, including engineering enhanced protein disaggregases based on Hsp104.
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Ransey E, Paredes E, Dey SK, Das SR, Heroux A, Macbeth MR. Crystal structure of the Entamoeba histolytica RNA lariat debranching enzyme EhDbr1 reveals a catalytic Zn 2+ /Mn 2+ heterobinucleation. FEBS Lett 2017; 591:2003-2010. [PMID: 28504306 DOI: 10.1002/1873-3468.12677] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/03/2017] [Accepted: 05/05/2017] [Indexed: 01/24/2023]
Abstract
The RNA lariat debranching enzyme, Dbr1, is a metallophosphoesterase that cleaves 2'-5' phosphodiester bonds within intronic lariats. Previous reports have indicated that Dbr1 enzymatic activity is supported by diverse metal ions including Ni2+ , Mn2+ , Mg2+ , Fe2+ , and Zn2+ . While in initial structures of the Entamoeba histolytica Dbr1 only one of the two catalytic metal-binding sites were observed to be occupied (with a Mn2+ ion), recent structures determined a Zn2+ /Fe2+ heterobinucleation. We solved a high-resolution X-ray crystal structure (1.8 Å) of the E. histolytica Dbr1 and determined a Zn2+ /Mn2+ occupancy. ICP-AES corroborate this finding, and in vitro debranching assays with fluorescently labeled branched substrates confirm activity.
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Affiliation(s)
- Elizabeth Ransey
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Eduardo Paredes
- Department of Chemistry and Center for Nucleic Acids & Technology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Sourav K Dey
- Department of Chemistry and Center for Nucleic Acids & Technology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Subha R Das
- Department of Chemistry and Center for Nucleic Acids & Technology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Annie Heroux
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY, USA
| | - Mark R Macbeth
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, IN, USA
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Human DBR1 modulates the recycling of snRNPs to affect alternative RNA splicing and contributes to the suppression of cancer development. Oncogene 2017; 36:5382-5391. [PMID: 28504715 PMCID: PMC5608638 DOI: 10.1038/onc.2017.150] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/03/2017] [Accepted: 04/14/2017] [Indexed: 12/16/2022]
Abstract
The contribution of RNA processing to tumorigenesis is understudied. Here, we report that the human RNA debranching enzyme (hDBR1), when inappropriately regulated, induces oncogenesis by causing RNA processing defects, for example, splicing defects. We found that wild-type p53 and hypoxia-inducible factor 1 co-regulate hDBR1 expression, and insufficient hDBR1 leads to a higher rate of exon skipping. Transcriptomic sequencing confirmed the effect of hDBR1 on RNA splicing, and metabolite profiling supported the observation that neoplasm is triggered by a decrease in hDBR1 expression both in vitro and in vivo. Most importantly, when modulating the expression of hDBR1, which was found to be generally low in malignant human tissues, higher expression of hDBR1 only affected exon-skipping activity in malignant cells. Together, our findings demonstrate previously unrecognized regulation and functions of hDBR1, with immediate clinical implications regarding the regulation of hDBR1 as an effective strategy for combating human cancer.
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Katolik A, Clark NE, Tago N, Montemayor EJ, Hart PJ, Damha MJ. Fluorescent Branched RNAs for High-Throughput Analysis of Dbr1 Enzyme Kinetics and Inhibition. ACS Chem Biol 2017; 12:622-627. [PMID: 28055181 DOI: 10.1021/acschembio.6b00971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have developed fluorescent 2',5' branched RNAs (bRNA) that permit real time monitoring of RNA lariat (intron) debranching enzyme (Dbr1) kinetics. These compounds contain fluorescein (FAM) on the 5' arm of the bRNA that is quenched by a dabcyl moiety on the 2' arm. Dbr1-mediated hydrolysis of the 2',5' linkage induces a large increase in fluorescence, providing a convenient assay for Dbr1 hydrolysis. We show that unlabeled bRNAs with non-native 2',5'-phosphodiester linkages, such as phosphoramidate or phosphorothioate, can inhibit Dbr1-mediated debranching with IC50 values in the low nanomolar range. In addition to measuring kinetic parameters of the debranching enzyme, these probes can be used for high throughput screening (HTS) of chemical libraries with the aim of identifying Dbr1 inhibitors, compounds that may be useful in treating neurodegenerative diseases and retroviral infections.
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Affiliation(s)
- Adam Katolik
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec H3A 0B8, Canada
| | - Nathaniel E. Clark
- Department
of Biochemistry and Structural Biology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
| | - Nobuhiro Tago
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec H3A 0B8, Canada
| | - Eric J. Montemayor
- Departments
of Biochemistry and Biomolecular Chemistry, University Of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - P. John Hart
- Department
of Biochemistry and Structural Biology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
- Department
of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, Texas 78229, United States
| | - Masad J. Damha
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec H3A 0B8, Canada
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Metal dependence and branched RNA cocrystal structures of the RNA lariat debranching enzyme Dbr1. Proc Natl Acad Sci U S A 2016; 113:14727-14732. [PMID: 27930312 DOI: 10.1073/pnas.1612729114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Intron lariats are circular, branched RNAs (bRNAs) produced during pre-mRNA splicing. Their unusual chemical and topological properties arise from branch-point nucleotides harboring vicinal 2',5'- and 3',5'-phosphodiester linkages. The 2',5'-bonds must be hydrolyzed by the RNA debranching enzyme Dbr1 before spliced introns can be degraded or processed into small nucleolar RNA and microRNA derived from intronic RNA. Here, we measure the activity of Dbr1 from Entamoeba histolytica by using a synthetic, dark-quenched bRNA substrate that fluoresces upon hydrolysis. Purified enzyme contains nearly stoichiometric equivalents of Fe and Zn per polypeptide and demonstrates turnover rates of ∼3 s-1 Similar rates are observed when apo-Dbr1 is reconstituted with Fe(II)+Zn(II) under aerobic conditions. Under anaerobic conditions, a rate of ∼4.0 s-1 is observed when apoenzyme is reconstituted with Fe(II). In contrast, apo-Dbr1 reconstituted with Mn(II) or Fe(II) under aerobic conditions is inactive. Diffraction data from crystals of purified enzyme using X-rays tuned to the Fe absorption edge show Fe partitions primarily to the β-pocket and Zn to the α-pocket. Structures of the catalytic mutant H91A in complex with 7-mer and 16-mer synthetic bRNAs reveal bona fide RNA branchpoints in the Dbr1 active site. A bridging hydroxide is in optimal position for nucleophilic attack of the scissile phosphate. The results clarify uncertainties regarding structure/function relationships in Dbr1 enzymes, and the fluorogenic probe permits high-throughput screening for inhibitors that may hold promise as treatments for retroviral infections and neurodegenerative disease.
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Schwer B, Khalid F, Shuman S. Mechanistic insights into the manganese-dependent phosphodiesterase activity of yeast Dbr1 with bis-p-nitrophenylphosphate and branched RNA substrates. RNA (NEW YORK, N.Y.) 2016; 22:1819-1827. [PMID: 27765821 PMCID: PMC5113202 DOI: 10.1261/rna.058552.116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/08/2016] [Indexed: 06/06/2023]
Abstract
Saccharomyces cerevisiae Dbr1 is a manganese-dependent RNA debranching enzyme that cleaves the 2'-5' phosphodiester bond of the lariat introns formed during pre-mRNA splicing. Dbr1 is a member of the binuclear metallophosphoesterase enzyme superfamily. We showed previously via alanine scanning that RNA debranching in vivo and in vitro depends on conserved active site residues His13, Asp40, Asn85, His86, His179, His231, and His233. Here, by extending the alanine scan, we added Cys11 to the ensemble of essential active site components. We report that Dbr1 has a vigorous manganese-dependent phosphodiesterase activity with the non-RNA substrate bis-p-nitrophenylphosphate. Whereas RNA debranching requires His86, bis-p-nitrophenylphosphatase activity does not. We interpret these and other structure-activity relations reported here in light of the crystal structures of Entamoeba Dbr1 and other homologous binuclear metallophosphodiesterases. Our results suggest that (i) Dbr1 adheres to the two-metal mechanism of the enzyme superfamily, but is distinguished by its reliance on a Cys11-Xaa-His13 motif to engage one of the catalytic metals instead of the Asp-Xaa-His element typical of other clades within the superfamily; (ii) His86 is a general acid catalyst that protonates the O2' leaving group of the RNA 2'-5' phosphodiester; and (iii) the favorable pKa of p-nitrophenol elides the strict need for a general acid during hydrolysis of bis-p-nitrophenylphosphate. The Dbr1 bis-p-nitrophenylphosphatase activity is well suited for high-throughput screening for inhibitors of debranching.
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Affiliation(s)
- Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
| | - Fahad Khalid
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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Specific Recognition of a Single-Stranded RNA Sequence by a Synthetic Antibody Fragment. J Mol Biol 2016; 428:4100-4114. [PMID: 27593161 PMCID: PMC5178103 DOI: 10.1016/j.jmb.2016.08.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 01/07/2023]
Abstract
Antibodies that bind RNA represent an unrealized source of reagents for synthetic biology and for characterizing cellular transcriptomes. However, facile access to RNA-binding antibodies requires the engineering of effective Fab libraries guided by the knowledge of the principles that govern RNA recognition. Here, we describe a Fab identified from a minimalist synthetic library during phage display against a branched RNA target. The Fab (BRG) binds with 20nM dissociation constant to a single-stranded RNA (ssRNA) sequence adjacent to the branch site and can block the action of debranchase enzyme. We report the crystal structure in complex with RNA target at 2.38Å. The Fab traps the RNA in a hairpin conformation that contains a 2-bp duplex capped by a tetraloop. The paratope surface consists of residues located in four complementarity-determining regions including a major contribution from H3, which adopts a helical structure that projects into a deep, wide groove formed by the RNA. The amino acid composition of the paratope reflects the library diversity, consisting mostly of tyrosine and serine residues and a small but significant contribution from a single arginine residue. This structure, involving the recognition of ssRNA via a stem-loop conformation, together with our two previous structures involving the recognition of an RNA hairpin loop and an RNA tertiary structure, reveals the capacity of minimalist libraries biased with tyrosine, serine, glycine, and arginine to form binding surfaces for specific RNA conformations and distinct levels of RNA structural hierarchy.
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46
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Gould GM, Paggi JM, Guo Y, Phizicky DV, Zinshteyn B, Wang ET, Gilbert WV, Gifford DK, Burge CB. Identification of new branch points and unconventional introns in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2016; 22:1522-34. [PMID: 27473169 PMCID: PMC5029451 DOI: 10.1261/rna.057216.116] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/02/2016] [Indexed: 05/18/2023]
Abstract
Spliced messages constitute one-fourth of expressed mRNAs in the yeast Saccharomyces cerevisiae, and most mRNAs in metazoans. Splicing requires 5' splice site (5'SS), branch point (BP), and 3' splice site (3'SS) elements, but the role of the BP in splicing control is poorly understood because BP identification remains difficult. We developed a high-throughput method, Branch-seq, to map BPs and 5'SSs of isolated RNA lariats. Applied to S. cerevisiae, Branch-seq detected 76% of expressed, annotated BPs and identified a comparable number of novel BPs. We performed RNA-seq to confirm associated 3'SS locations, identifying some 200 novel splice junctions, including an AT-AC intron. We show that several yeast introns use two or even three different BPs, with effects on 3'SS choice, protein coding potential, or RNA stability, and identify novel introns whose splicing changes during meiosis or in response to stress. Together, these findings show unanticipated complexity of splicing in yeast.
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Affiliation(s)
- Genevieve M Gould
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Joseph M Paggi
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yuchun Guo
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - David V Phizicky
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Boris Zinshteyn
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Eric T Wang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Wendy V Gilbert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - David K Gifford
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Christopher B Burge
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Osman I, Tay MLI, Pek JW. Stable intronic sequence RNAs (sisRNAs): a new layer of gene regulation. Cell Mol Life Sci 2016; 73:3507-19. [PMID: 27147469 PMCID: PMC11108444 DOI: 10.1007/s00018-016-2256-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 02/05/2023]
Abstract
Upon splicing, introns are rapidly degraded. Hence, RNAs derived from introns are commonly deemed as junk sequences. However, the discoveries of intronic-derived small nucleolar RNAs (snoRNAs), small Cajal body associated RNAs (scaRNAs) and microRNAs (miRNAs) suggested otherwise. These non-coding RNAs are shown to play various roles in gene regulation. In this review, we highlight another class of intron-derived RNAs known as stable intronic sequence RNAs (sisRNAs). sisRNAs have been observed since the 1980 s; however, we are only beginning to understand their biological significance. Recent studies have shown or suggested that sisRNAs regulate their own host's gene expression, function as molecular sinks or sponges, and regulate protein translation. We propose that sisRNAs function as an additional layer of gene regulation in the cells.
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Affiliation(s)
- Ismail Osman
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Mandy Li-Ian Tay
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Jun Wei Pek
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore.
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48
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Kralovicova J, Vorechovsky I. Alternative splicing of U2AF1 reveals a shared repression mechanism for duplicated exons. Nucleic Acids Res 2016; 45:417-434. [PMID: 27566151 PMCID: PMC5224494 DOI: 10.1093/nar/gkw733] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 12/30/2022] Open
Abstract
The auxiliary factor of U2 small nuclear ribonucleoprotein (U2AF) facilitates branch point (BP) recognition and formation of lariat introns. The gene for the 35-kD subunit of U2AF gives rise to two protein isoforms (termed U2AF35a and U2AF35b) that are encoded by alternatively spliced exons 3 and Ab, respectively. The splicing recognition sequences of exon 3 are less favorable than exon Ab, yet U2AF35a expression is higher than U2AF35b across tissues. We show that U2AF35b repression is facilitated by weak, closely spaced BPs next to a long polypyrimidine tract of exon Ab. Each BP lacked canonical uridines at position -2 relative to the BP adenines, with efficient U2 base-pairing interactions predicted only for shifted registers reminiscent of programmed ribosomal frameshifting. The BP cluster was compensated by interactions involving unpaired cytosines in an upstream, EvoFold-predicted stem loop (termed ESL) that binds FUBP1/2. Exon Ab inclusion correlated with predicted free energies of mutant ESLs, suggesting that the ESL operates as a conserved rheostat between long inverted repeats upstream of each exon. The isoform-specific U2AF35 expression was U2AF65-dependent, required interactions between the U2AF-homology motif (UHM) and the α6 helix of U2AF35, and was fine-tuned by exon Ab/3 variants. Finally, we identify tandem homologous exons regulated by U2AF and show that their preferential responses to U2AF65-related proteins and SRSF3 are associated with unpaired pre-mRNA segments upstream of U2AF-repressed 3′ss. These results provide new insights into tissue-specific subfunctionalization of duplicated exons in vertebrate evolution and expand the repertoire of exon repression mechanisms that control alternative splicing.
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Affiliation(s)
- Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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Granados-Riveron JT, Aquino-Jarquin G. The complexity of the translation ability of circRNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1245-51. [PMID: 27449861 DOI: 10.1016/j.bbagrm.2016.07.009] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 06/21/2016] [Accepted: 07/15/2016] [Indexed: 12/12/2022]
Abstract
Circular RNAs (circRNAs) are a new class of long non-coding RNAs that play a potential role in gene expression regulation, acting as efficient microRNAs sponges. The latest surprise concerning circRNAs is that we now know that they can serve as transcriptional activators in human cells, indicating that circRNAs are involved in important regulatory tasks. Recently, new insight has been gained about the coding potential of circular viroid RNAs, as well as the presence of Internal Ribosomal Entry Sites (IRES) allowing the formation of peptides or proteins from circular RNA. Here, we discuss the current state of our knowledge regarding evidence supporting the hypothesis that circRNAs serve as protein-coding sequences in vitro and in vivo. Also, we remark on the difficulties of their identification and highlight some tools currently available for exploring the coding potential of circRNA.
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Affiliation(s)
- Javier T Granados-Riveron
- Laboratorio de Investigación en Genómica, Genética y Bioinformática, Torre de Hemato-Oncología, 4to Piso, Sección 2, Hospital Infantil de México, Federico Gómez, Mexico
| | - Guillermo Aquino-Jarquin
- Laboratorio de Investigación en Genómica, Genética y Bioinformática, Torre de Hemato-Oncología, 4to Piso, Sección 2, Hospital Infantil de México, Federico Gómez, Mexico.
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50
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Novel Intronic RNA Structures Contribute to Maintenance of Phenotype in Saccharomyces cerevisiae. Genetics 2016; 203:1469-81. [PMID: 27194751 PMCID: PMC4937481 DOI: 10.1534/genetics.115.185363] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 05/13/2016] [Indexed: 12/18/2022] Open
Abstract
The Saccharomyces cerevisiae genome has undergone extensive intron loss during its evolutionary history. It has been suggested that the few remaining introns (in only 5% of protein-coding genes) are retained because of their impact on function under stress conditions. Here, we explore the possibility that novel noncoding RNA structures (ncRNAs) are embedded within intronic sequences and are contributing to phenotype and intron retention in yeast. We employed de novo RNA structure prediction tools to screen intronic sequences in S. cerevisiae and 36 other fungi. We identified and validated 19 new intronic RNAs via RNA sequencing (RNA-seq) and RT-PCR. Contrary to the common belief that excised introns are rapidly degraded, we found that, in six cases, the excised introns were maintained intact in the cells. In another two cases we showed that the ncRNAs were further processed from their introns. RNA-seq analysis confirmed that introns in ribosomal protein genes are more highly expressed when they contain predicted RNA structures. We deleted the novel intronic RNA structure within the GLC7 intron and showed that this region, rather than the intron itself, is responsible for the cell’s ability to respond to salt stress. We also showed a direct association between the in cis presence of the intronic RNA and GLC7 expression. Overall, these data support the notion that some introns may have been maintained in the genome because they harbor functional RNA structures.
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