1
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Wu YW, Deng ZQ, Rong Y, Bu GW, Wu YK, Wu X, Cheng H, Fan HY. RNA surveillance by the RNA helicase MTR4 determines volume of mouse oocytes. Dev Cell 2024:S1534-5807(24)00537-9. [PMID: 39378876 DOI: 10.1016/j.devcel.2024.09.009] [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: 11/04/2023] [Revised: 04/21/2024] [Accepted: 09/10/2024] [Indexed: 10/10/2024]
Abstract
Oocytes are the largest cell type in multicellular animals. Here, we show that mRNA transporter 4 (MTR4) is indispensable for oocyte growth and functions as part of the RNA surveillance mechanism, which is responsible for nuclear waste RNA clearance. MTR4 ensures the normal post-transcriptional processing of maternal RNAs, their nuclear export to the cytoplasm, and the accumulation of properly processed transcripts. Oocytes with Mtr4 knockout fail to accumulate sufficient and normal transcripts in the cytoplasm and cannot grow to normal sizes. MTR4-dependent RNA surveillance has a previously unrecognized function in maintaining a stable nuclear environment for the establishment of non-canonical histone H3 lysine-4 trimethylation and chromatin reorganization, which is necessary to form a nucleolus-like structure in oocytes. In conclusion, MTR4-dependent RNA surveillance activity is a checkpoint that allows oocytes to grow to a normal size, undergo nuclear and cytoplasmic maturation, and acquire developmental competence.
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Affiliation(s)
- Yun-Wen Wu
- MOE Key Laboratory for Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Zuo-Qi Deng
- MOE Key Laboratory for Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Yan Rong
- Zhejiang Key Laboratory of Precise Protection and Promotion of Fertility, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Guo-Wei Bu
- Center for Biomedical Research, Shaoxing Institute, Zhejiang University, Shaoxing 312000, China
| | - Yu-Ke Wu
- MOE Key Laboratory for Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xuan Wu
- MOE Key Laboratory for Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Hong Cheng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Heng-Yu Fan
- MOE Key Laboratory for Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Zhejiang Key Laboratory of Precise Protection and Promotion of Fertility, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Center for Biomedical Research, Shaoxing Institute, Zhejiang University, Shaoxing 312000, China.
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2
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Garland W, Jensen TH. Nuclear sorting of short RNA polymerase II transcripts. Mol Cell 2024; 84:3644-3655. [PMID: 39366352 DOI: 10.1016/j.molcel.2024.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 08/14/2024] [Accepted: 08/20/2024] [Indexed: 10/06/2024]
Abstract
Mammalian genomes produce an abundance of short RNA. This is, to a large extent, due to the genome-wide and spurious activity of RNA polymerase II (RNAPII). However, it is also because the vast majority of initiating RNAPII, regardless of the transcribed DNA unit, terminates within a ∼3-kb early "pausing zone." Given that the resultant RNAs constitute both functional and non-functional species, their proper sorting is critical. One way to think about such quality control (QC) is that transcripts, from their first emergence, are relentlessly targeted by decay factors, which may only be avoided by engaging protective processing pathways. In a molecular materialization of this concept, recent progress has found that both "destructive" and "productive" RNA effectors assemble at the 5' end of capped RNA, orchestrated by the essential arsenite resistance protein 2 (ARS2) protein. Based on this principle, we here discuss early QC mechanisms and how these might sort short RNAs to their final fates.
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Affiliation(s)
- William Garland
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, Aarhus, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, Aarhus, Denmark.
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3
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Glossop MS, Chelysheva I, Ketley RF, Alagia A, Gullerova M. TIRR regulates mRNA export and association with P-bodies in response to DNA damage. Nucleic Acids Res 2024:gkae688. [PMID: 39119906 DOI: 10.1093/nar/gkae688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 07/15/2024] [Accepted: 07/25/2024] [Indexed: 08/10/2024] Open
Abstract
To ensure the integrity of our genetic code, a coordinated network of signalling and repair proteins, known as the DNA damage response (DDR), detects and repairs DNA insults, the most toxic being double-strand breaks (DSBs). Tudor interacting repair regulator (TIRR) is a key factor in DSB repair, acting through its interaction with p53 binding protein 1 (53BP1). TIRR is also an RNA binding protein, yet its role in RNA regulation during the DDR remains elusive. Here, we show that TIRR selectively binds to a subset of messenger RNAs (mRNAs) in response to DNA damage. Upon DNA damage, TIRR interacts with the nuclear export protein Exportin-1 through a nuclear export signal. Furthermore, TIRR plays a crucial role in the modulation of RNA processing bodies (PBs). TIRR itself and TIRR-bound RNA co-localize with PBs, and TIRR depletion results in nuclear RNA retention and impaired PB formation. We also suggest a potential link between TIRR-regulated RNA export and efficient DDR. This work reveals intricate involvement of TIRR in orchestrating mRNA nuclear export and storage within PBs, emphasizing its significance in the regulation of RNA-mediated DDR.
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Affiliation(s)
- Michelle S Glossop
- Sir William Dunn School of Pathology, Medical Sciences Division, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Irina Chelysheva
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford OX3 7LE, UK
| | - Ruth F Ketley
- Sir William Dunn School of Pathology, Medical Sciences Division, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Adele Alagia
- Sir William Dunn School of Pathology, Medical Sciences Division, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Monika Gullerova
- Sir William Dunn School of Pathology, Medical Sciences Division, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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4
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Zhuravskaya A, Yap K, Hamid F, Makeyev EV. Alternative splicing coupled to nonsense-mediated decay coordinates downregulation of non-neuronal genes in developing mouse neurons. Genome Biol 2024; 25:162. [PMID: 38902825 PMCID: PMC11188260 DOI: 10.1186/s13059-024-03305-8] [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: 07/08/2023] [Accepted: 06/07/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND The functional coupling between alternative pre-mRNA splicing (AS) and the mRNA quality control mechanism called nonsense-mediated decay (NMD) can modulate transcript abundance. Previous studies have identified several examples of such a regulation in developing neurons. However, the systems-level effects of AS-NMD in this context are poorly understood. RESULTS We developed an R package, factR2, which offers a comprehensive suite of AS-NMD analysis functions. Using this tool, we conducted a longitudinal analysis of gene expression in pluripotent stem cells undergoing induced neuronal differentiation. Our analysis uncovers hundreds of AS-NMD events with significant potential to regulate gene expression. Notably, this regulation is significantly overrepresented in specific functional groups of developmentally downregulated genes. Particularly strong association with gene downregulation is detected for alternative cassette exons stimulating NMD upon their inclusion into mature mRNA. By combining bioinformatic analyses with CRISPR/Cas9 genome editing and other experimental approaches we show that NMD-stimulating cassette exons regulated by the RNA-binding protein PTBP1 dampen the expression of their genes in developing neurons. We also provided evidence that the inclusion of NMD-stimulating cassette exons into mature mRNAs is temporally coordinated with NMD-independent gene repression mechanisms. CONCLUSIONS Our study provides an accessible workflow for the discovery and prioritization of AS-NMD targets. It further argues that the AS-NMD pathway plays a widespread role in developing neurons by facilitating the downregulation of functionally related non-neuronal genes.
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Affiliation(s)
- Anna Zhuravskaya
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Karen Yap
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Fursham Hamid
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
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5
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Han X, Xing L, Hong Y, Zhang X, Hao B, Lu JY, Huang M, Wang Z, Ma S, Zhan G, Li T, Hao X, Tao Y, Li G, Zhou S, Zheng Z, Shao W, Zeng Y, Ma D, Zhang W, Xie Z, Deng H, Yan J, Deng W, Shen X. Nuclear RNA homeostasis promotes systems-level coordination of cell fate and senescence. Cell Stem Cell 2024; 31:694-716.e11. [PMID: 38631356 DOI: 10.1016/j.stem.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/01/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Understanding cellular coordination remains a challenge despite knowledge of individual pathways. The RNA exosome, targeting a wide range of RNA substrates, is often downregulated in cellular senescence. Utilizing an auxin-inducible system, we observed that RNA exosome depletion in embryonic stem cells significantly affects the transcriptome and proteome, causing pluripotency loss and pre-senescence onset. Mechanistically, exosome depletion triggers acute nuclear RNA aggregation, disrupting nuclear RNA-protein equilibrium. This disturbance limits nuclear protein availability and hinders polymerase initiation and engagement, reducing gene transcription. Concurrently, it promptly disrupts nucleolar transcription, ribosomal processes, and nuclear exporting, resulting in a translational shutdown. Prolonged exosome depletion induces nuclear structural changes resembling senescent cells, including aberrant chromatin compaction, chromocenter disassembly, and intensified heterochromatic foci. These effects suggest that the dynamic turnover of nuclear RNA orchestrates crosstalk between essential processes to optimize cellular function. Disruptions in nuclear RNA homeostasis result in systemic functional decline, altering the cell state and promoting senescence.
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Affiliation(s)
- Xue Han
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Linqing Xing
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yantao Hong
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Xuechun Zhang
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Bo Hao
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - J Yuyang Lu
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Mengyuan Huang
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zuhui Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Shaoqian Ma
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Ge Zhan
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Tong Li
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaowen Hao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yibing Tao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Guanwen Li
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Shuqin Zhou
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zheng Zheng
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Wen Shao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yitian Zeng
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Dacheng Ma
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and Systems Biology, Department of Automation, Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China
| | - Wenhao Zhang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhen Xie
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and Systems Biology, Department of Automation, Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiangwei Yan
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xiaohua Shen
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China; SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China.
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6
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Xu M, Qian K, Shao H, Yao Y, Nair V, Ye J, Qin A. 3'UTR of ALV-J can affect viral replication through promoting transcription and mRNA nuclear export. J Virol 2023; 97:e0115223. [PMID: 37902396 PMCID: PMC10688361 DOI: 10.1128/jvi.01152-23] [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: 07/27/2023] [Accepted: 09/29/2023] [Indexed: 10/31/2023] Open
Abstract
IMPORTANCE 3'UTRs can affect gene transcription and post-transcriptional regulation in multiple ways, further influencing the function of proteins in a unique manner. Recently, ALV-J has been mutating and evolving rapidly, especially the 3'UTR of viral genome. Meanwhile, clinical symptoms caused by ALV-J have changed significantly. In this study, we found that the ALV-J strains containing △-r-TM-type 3'UTR are the most abundant. By constructing ALV-J infectious clones and subgenomic vectors containing different 3'UTRs, we prove that 3'UTRs directly affect viral tissue preference and can promote virus replication as an enhancer. ALV-J strain containing 3'UTR of △-r-TM proliferated fastest in primary cells. All five forms of 3'UTRs can assist intron-containing viral mRNA nuclear export, with similar efficiency. ALV-J mRNA half-life is not influenced by different 3'UTRs. Our results dissect the roles of 3'UTR on regulating viral replication and pathogenicity, providing novel insights into potential anti-viral strategies.
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Affiliation(s)
- Moru Xu
- Ministry of Education Key Lab for Avian Preventive Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Kun Qian
- Ministry of Education Key Lab for Avian Preventive Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China
| | - Hongxia Shao
- Ministry of Education Key Lab for Avian Preventive Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China
| | - Yongxiu Yao
- The Pirbright Institute and UK-China Centre of Excellence on Avian Disease Research, Surrey, United Kingdom
| | - Venugopal Nair
- The Pirbright Institute and UK-China Centre of Excellence on Avian Disease Research, Surrey, United Kingdom
| | - Jianqiang Ye
- Ministry of Education Key Lab for Avian Preventive Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China
| | - Aijian Qin
- Ministry of Education Key Lab for Avian Preventive Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China
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7
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Egberink RO, van Asbeck AH, Boswinkel M, Muradjan G, Dieker J, Brock R. Deciphering Structural Determinants Distinguishing Active from Inactive Cell-Penetrating Peptides for Cytosolic mRNA Delivery. Bioconjug Chem 2023; 34:1822-1834. [PMID: 37733627 PMCID: PMC10587869 DOI: 10.1021/acs.bioconjchem.3c00346] [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: 08/07/2023] [Revised: 09/07/2023] [Indexed: 09/23/2023]
Abstract
The formation of noncovalent complexes by mixing of positively charged polymers with negatively charged oligonucleotides (ONs) is a widely explored concept in nanomedicine to achieve cellular delivery of ONs. Uptake of ON complexes occurs through endocytosis, which then requires release of ON from endosomes. As one type of polymer, cell-penetrating peptides (CPPs) are being used which are peptides of about 8-30 amino acids in length. However, only a few CPPs yield effective cytosolic ON delivery and activity. Several strategies have been devised to increase cellular uptake and enhance endosomal release, among which an increase of osmotic pressure through the so-called proton sponge effect, disruption of membrane integrity through membrane activity, and disulfide-mediated polymerization. Here, we address the relevance of these concepts for mRNA delivery by incorporating structural features into the human lactoferrin-derived CPP, which shows uptake but not delivery. The incorporation of histidines was explored to address osmotic pressure and structural motifs of the delivery-active CPP PepFect14 (PF14) to address membrane disturbance, and finally, the impact of polymerization was explored. Whereas oligomerization increased the stability of polyplexes against heparin-induced decomplexation, neither this approach nor the incorporation of histidine residues to promote a proton-sponge effect yielded activity. Also, the replacement of arginine residues with lysine or ornithine residues, as in PF14, was without effect, even though all polyplexes showed cellular uptake. Ultimately, sufficient activity could only be achieved by transferring amphipathic sequence motifs from PF14 into the hLF context with some benefit of oligomerization demonstrating overarching principles of delivery for CPPs, lipid nanoparticles, and other types of delivery polymers.
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Affiliation(s)
- Rik Oude Egberink
- Department
of Medical BioSciences, Research Institute for Medical Innovation, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Alexander H. van Asbeck
- Department
of Medical BioSciences, Research Institute for Medical Innovation, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Milou Boswinkel
- Department
of Medical BioSciences, Research Institute for Medical Innovation, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Grigor Muradjan
- Department
of Medical BioSciences, Research Institute for Medical Innovation, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Jürgen Dieker
- Department
of Medical BioSciences, Research Institute for Medical Innovation, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Roland Brock
- Department
of Medical BioSciences, Research Institute for Medical Innovation, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Department
of Medical Biochemistry, College of Medicine and Medical Sciences, Arabian Gulf University, Manama 329, Bahrain
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8
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Yin Y, Shen X. Noncoding RNA-chromatin association: Functions and mechanisms. FUNDAMENTAL RESEARCH 2023; 3:665-675. [PMID: 38933302 PMCID: PMC11197541 DOI: 10.1016/j.fmre.2023.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/12/2023] [Accepted: 03/23/2023] [Indexed: 06/28/2024] Open
Abstract
Pervasive transcription of the mammalian genome produces hundreds of thousands of noncoding RNAs (ncRNAs). Numerous studies have suggested that some of these ncRNAs regulate multiple cellular processes and play important roles in physiological and pathological processes. Notably, a large subset of ncRNAs is enriched on chromatin and participates in regulating gene expression and the dynamics of chromatin structure and status. In this review, we summarize recent advances in the functional study of chromatin-associated ncRNAs and mechanistic insights into how these ncRNAs associate with chromatin. We also discuss the potential future challenges which still need to be overcome in this field.
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Affiliation(s)
- Yafei Yin
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Yuhangtang Road, Hangzhou, Zhejiang 310058, China
| | - Xiaohua Shen
- Tsinghua-Peking Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing 100084, China
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9
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Rouvière JO, Salerno-Kochan A, Lykke-Andersen S, Garland W, Dou Y, Rathore O, Molska EŠ, Wu G, Schmid M, Bugai A, Jakobsen L, Žumer K, Cramer P, Andersen JS, Conti E, Jensen TH. ARS2 instructs early transcription termination-coupled RNA decay by recruiting ZC3H4 to nascent transcripts. Mol Cell 2023:S1097-2765(23)00384-2. [PMID: 37329882 DOI: 10.1016/j.molcel.2023.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/29/2023] [Accepted: 05/18/2023] [Indexed: 06/19/2023]
Abstract
The RNA-binding ARS2 protein is centrally involved in both early RNA polymerase II (RNAPII) transcription termination and transcript decay. Despite its essential nature, the mechanisms by which ARS2 enacts these functions have remained unclear. Here, we show that a conserved basic domain of ARS2 binds a corresponding acidic-rich, short linear motif (SLiM) in the transcription restriction factor ZC3H4. This interaction recruits ZC3H4 to chromatin to elicit RNAPII termination, independent of other early termination pathways defined by the cleavage and polyadenylation (CPA) and Integrator (INT) complexes. We find that ZC3H4, in turn, forms a direct connection to the nuclear exosome targeting (NEXT) complex, hereby facilitating rapid degradation of the nascent RNA. Hence, ARS2 instructs the coupled transcription termination and degradation of the transcript onto which it is bound. This contrasts with ARS2 function at CPA-instructed termination sites where the protein exclusively partakes in RNA suppression via post-transcriptional decay.
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Affiliation(s)
- Jérôme O Rouvière
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Anna Salerno-Kochan
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Munich, Germany
| | - Søren Lykke-Andersen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - William Garland
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Yuhui Dou
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Om Rathore
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Ewa Šmidová Molska
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Guifen Wu
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Andrii Bugai
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Lis Jakobsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Kristina Žumer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Munich, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark.
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10
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Ramdas P, Chande A. SERINC5 Mediates a Postintegration Block to HIV-1 Gene Expression in Macrophages. mBio 2023; 14:e0016623. [PMID: 36976020 PMCID: PMC10127607 DOI: 10.1128/mbio.00166-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/01/2023] [Indexed: 03/29/2023] Open
Abstract
HIV-1 antagonizes SERINC5 by redundant mechanisms, primarily through Nef and additionally via envelope glycoprotein. Paradoxically, HIV-1 preserves Nef function to ensure the exclusion of SERINC5 from virion incorporation regardless of the availability of envelope that can confer resistance, suggesting additional roles of the virion-incorporated host factor. Here, we report an unusual mode of SERINC5 action in inhibiting viral gene expression. This inhibition is observed only in the myeloid lineage cells but not in the cells of epithelial or lymphoid origin. We found that SERINC5-bearing viruses induce the expression of RPL35 and DRAP1 in macrophages, and these host proteins intercept HIV-1 Tat from binding to and recruiting a mammalian capping enzyme (MCE1) to the HIV-1 transcriptional complex. As a result, uncapped viral transcripts are synthesized, leading to the inhibition of viral protein synthesis and subsequent progeny virion biogenesis. Cell-type-specific inhibition of HIV-1 gene expression thus exemplifies a novel antiviral function of virion-incorporated SERINC5. IMPORTANCE In addition to Nef, HIV-1 envelope glycoprotein has been shown to modulate SERINC5-mediated inhibition. Counterintuitively, Nef from the same isolates preserves the ability to prevent SERINC5 incorporation into virions, implying additional functions of the host protein. We identify that virion-associated SERINC5 can manifest an antiviral mechanism independent of the envelope glycoprotein to regulate HIV-1 gene expression in macrophages. This mechanism is exhibited by affecting the viral RNA capping and is plausibly adopted by the host to overcome the envelope glycoprotein-mediated resistance to SERINC5 restriction.
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Affiliation(s)
- Pavitra Ramdas
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
| | - Ajit Chande
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
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11
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Matabishi-Bibi L, Challal D, Barucco M, Libri D, Babour A. Termination of the unfolded protein response is guided by ER stress-induced HAC1 mRNA nuclear retention. Nat Commun 2022; 13:6331. [PMID: 36284099 PMCID: PMC9596429 DOI: 10.1038/s41467-022-34133-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/14/2022] [Indexed: 12/25/2022] Open
Abstract
Cellular homeostasis is maintained by surveillance mechanisms that intervene at virtually every step of gene expression. In the nucleus, the yeast chromatin remodeler Isw1 holds back maturing mRNA ribonucleoparticles to prevent their untimely export, but whether this activity operates beyond quality control of mRNA biogenesis to regulate gene expression is unknown. Here, we identify the mRNA encoding the central effector of the unfolded protein response (UPR) HAC1, as an Isw1 RNA target. The direct binding of Isw1 to the 3' untranslated region of HAC1 mRNA restricts its nuclear export and is required for accurate UPR abatement. Accordingly, ISW1 inactivation sensitizes cells to endoplasmic reticulum (ER) stress while its overexpression reduces UPR induction. Our results reveal an unsuspected mechanism, in which binding of ER-stress induced Isw1 to HAC1 mRNA limits its nuclear export, providing a feedback loop that fine-tunes UPR attenuation to guarantee homeostatic adaptation to ER stress.
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Affiliation(s)
- Laura Matabishi-Bibi
- grid.508487.60000 0004 7885 7602Univ Paris Diderot, Sorbonne Paris Cité, INSERM U944, CNRS UMR7212, Hôpital St. Louis 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
| | - Drice Challal
- grid.457334.20000 0001 0667 2738Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Mara Barucco
- grid.461913.80000 0001 0676 2143Institut Jacques Monod, Univ Paris Diderot, Sorbonne Paris Cité, CNRS, Bâtiment Buffon, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Domenico Libri
- grid.429192.50000 0004 0599 0285Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
| | - Anna Babour
- grid.508487.60000 0004 7885 7602Univ Paris Diderot, Sorbonne Paris Cité, INSERM U944, CNRS UMR7212, Hôpital St. Louis 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
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12
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Schroader JH, Jones LA, Meng R, Shorrock HK, Richardson J, Shaughnessy S, Lin Q, Begley T, Berglund J, Fuchs G, Handley M, Reddy K. Disease-associated inosine misincorporation into RNA hinders translation. Nucleic Acids Res 2022; 50:9306-9318. [PMID: 35979951 PMCID: PMC9458462 DOI: 10.1093/nar/gkac709] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 07/08/2022] [Accepted: 08/06/2022] [Indexed: 12/24/2022] Open
Abstract
Failure to prevent accumulation of the non-canonical nucleotide inosine triphosphate (ITP) by inosine triphosphate pyrophosphatase (ITPase) during nucleotide synthesis results in misincorporation of inosine into RNA and can cause severe and fatal developmental anomalies in humans. While the biochemical activity of ITPase is well understood, the pathogenic basis of ITPase deficiency and the molecular and cellular consequences of ITP misincorporation into RNA remain cryptic. Here, we demonstrate that excess ITP in the nucleotide pool during in vitro transcription results in T7 polymerase-mediated inosine misincorporation in luciferase RNA. In vitro translation of inosine-containing luciferase RNA reduces resulting luciferase activity, which is only partly explained by reduced abundance of the luciferase protein produced. Using Oxford Nanopore Direct RNA sequencing, we reveal inosine misincorporation to be stochastic but biased largely towards misincorporation in place of guanosine, with evidence for misincorporation also in place of cytidine, adenosine and uridine. Inosine misincorporation into RNA is also detected in Itpa-null mouse embryonic heart tissue as an increase in relative variants compared with the wild type using Illumina RNA sequencing. By generating CRISPR/Cas9 rat H9c2 Itpa-null cardiomyoblast cells, we validate a translation defect in cells that accumulate inosine within endogenous RNA. Furthermore, we observe hindered cellular translation of transfected luciferase RNA containing misincorporated inosine in both wild-type and Itpa-null cells. We therefore conclude that inosine misincorporation into RNA perturbs translation, thus providing mechanistic insight linking ITPase deficiency, inosine accumulation and pathogenesis.
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Affiliation(s)
| | | | - Ryan Meng
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Hannah K Shorrock
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jared I Richardson
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biochemistry and Molecular Biology, Center for NeuroGenetics, University of Florida, Gainesville, FL 32611, USA
| | - Sharon M Shaughnessy
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Qishan Lin
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,RNA Epitranscriptomics & Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - Thomas J Begley
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA,RNA Epitranscriptomics & Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - J Andrew Berglund
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biochemistry and Molecular Biology, Center for NeuroGenetics, University of Florida, Gainesville, FL 32611, USA
| | - Gabriele Fuchs
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Mark T Handley
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Kaalak Reddy
- *To whom correspondence should be addressed. Tel: +1 518 442 1464;
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13
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Duan L, Zaepfel BL, Aksenova V, Dasso M, Rothstein JD, Kalab P, Hayes LR. Nuclear RNA binding regulates TDP-43 nuclear localization and passive nuclear export. Cell Rep 2022; 40:111106. [PMID: 35858577 PMCID: PMC9345261 DOI: 10.1016/j.celrep.2022.111106] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/26/2022] [Accepted: 06/27/2022] [Indexed: 11/27/2022] Open
Abstract
Nuclear clearance of the RNA-binding protein TDP-43 is a hallmark of neurodegeneration and an important therapeutic target. Our current understanding of TDP-43 nucleocytoplasmic transport does not fully explain its predominantly nuclear localization or mislocalization in disease. Here, we show that TDP-43 exits nuclei by passive diffusion, independent of facilitated mRNA export. RNA polymerase II blockade and RNase treatment induce TDP-43 nuclear efflux, suggesting that nuclear RNAs sequester TDP-43 in nuclei and limit its availability for passive export. Induction of TDP-43 nuclear efflux by short, GU-rich oligomers (presumably by outcompeting TDP-43 binding to endogenous nuclear RNAs), and nuclear retention conferred by splicing inhibition, demonstrate that nuclear TDP-43 localization depends on binding to GU-rich nuclear RNAs. Indeed, RNA-binding domain mutations markedly reduce TDP-43 nuclear localization and abolish transcription blockade-induced nuclear efflux. Thus, the nuclear abundance of GU-RNAs, dictated by the balance of transcription, pre-mRNA processing, and RNA export, regulates TDP-43 nuclear localization.
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Affiliation(s)
- Lauren Duan
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Benjamin L Zaepfel
- Biochemistry, Cellular and Molecular Biology Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Vasilisa Aksenova
- Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mary Dasso
- Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Petr Kalab
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Lindsey R Hayes
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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14
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Wu M, Schmid M, Jensen T, Sandelin A. Computational identification of signals predictive for nuclear RNA exosome degradation pathway targeting. NAR Genom Bioinform 2022; 4:lqac071. [PMID: 36128426 PMCID: PMC9477074 DOI: 10.1093/nargab/lqac071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 08/05/2022] [Accepted: 09/01/2022] [Indexed: 11/15/2022] Open
Abstract
The RNA exosome degrades transcripts in the nucleoplasm of mammalian cells. Its substrate specificity is mediated by two adaptors: the ‘nuclear exosome targeting (NEXT)’ complex and the ‘poly(A) exosome targeting (PAXT)’ connection. Previous studies have revealed some DNA/RNA elements that differ between the two pathways, but how informative these features are for distinguishing pathway targeting, or whether additional genomic features that are informative for such classifications exist, is unknown. Here, we leverage the wealth of available genomic data and develop machine learning models that predict exosome targets and subsequently rank the features the models use by their predictive power. As expected, features around transcript end sites were most predictive; specifically, the lack of canonical 3′ end processing was highly predictive of NEXT targets. Other associated features, such as promoter-proximal G/C content and 5′ splice sites, were informative, but only for distinguishing NEXT and not PAXT targets. Finally, we discovered predictive features not previously associated with exosome targeting, in particular RNA helicase DDX3X binding sites. Overall, our results demonstrate that nucleoplasmic exosome targeting is to a large degree predictable, and our approach can assess the predictive power of previously known and new features in an unbiased way.
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Affiliation(s)
- Mengjun Wu
- The Bioinformatics Centre, Department of Biology and Biotech and Research Innovation Centre, University of Copenhagen , Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet , 171 65 Solna , Sweden
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University , Universitetsbyen 81, Aarhus , DK-8000, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University , Universitetsbyen 81, Aarhus , DK-8000, Denmark
| | - Albin Sandelin
- The Bioinformatics Centre, Department of Biology and Biotech and Research Innovation Centre, University of Copenhagen , Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
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15
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Richter F, Plehn JE, Bessler L, Hertler J, Jörg M, Cirzi C, Tuorto F, Friedland K, Helm M. RNA marker modifications reveal the necessity for rigorous preparation protocols to avoid artifacts in epitranscriptomic analysis. Nucleic Acids Res 2022; 50:4201-4215. [PMID: 34850949 PMCID: PMC9071408 DOI: 10.1093/nar/gkab1150] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/31/2021] [Accepted: 11/03/2021] [Indexed: 12/16/2022] Open
Abstract
The accurate definition of an epitranscriptome is endangered by artefacts resulting from RNA degradation after cell death, a ubiquitous yet little investigated process. By tracing RNA marker modifications through tissue preparation protocols, we identified a major blind spot from daily lab routine, that has massive impact on modification analysis in small RNAs. In particular, m6,6A and Am as co-varying rRNA marker modifications, appeared in small RNA fractions following rRNA degradation in vitro and in cellulo. Analysing mouse tissue at different time points post mortem, we tracked the progress of intracellular RNA degradation after cell death, and found it reflected in RNA modification patterns. Differences were dramatic between liver, where RNA degradation commenced immediately after death, and brain, yielding essentially undamaged RNA. RNA integrity correlated with low amounts of co-varying rRNA markers. Thus validated RNA preparations featured differentially modified tRNA populations whose information content allowed a distinction even among the related brain tissues cortex, cerebellum and hippocampus. Inversely, advanced cell death correlated with high rRNA marker content, and correspondingly little with the naïve state of living tissue. Therefore, unless RNA and tissue preparations are executed with utmost care, interpretation of modification patterns in tRNA and small RNA are prone to artefacts.
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Affiliation(s)
- Florian Richter
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
| | - Johanna E Plehn
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
| | - Larissa Bessler
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
| | - Jasmin Hertler
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
| | - Marko Jörg
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
| | - Cansu Cirzi
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ) 69120 Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg 69120 Heidelberg, Germany
| | - Francesca Tuorto
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance69120 Heidelberg, Germany
| | - Kristina Friedland
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
| | - Mark Helm
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5 55128 Mainz, Germany
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16
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Lange H, Gagliardi D. Catalytic activities, molecular connections, and biological functions of plant RNA exosome complexes. THE PLANT CELL 2022; 34:967-988. [PMID: 34954803 PMCID: PMC8894942 DOI: 10.1093/plcell/koab310] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/16/2021] [Indexed: 05/08/2023]
Abstract
RNA exosome complexes provide the main 3'-5'-exoribonuclease activities in eukaryotic cells and contribute to the maturation and degradation of virtually all types of RNA. RNA exosomes consist of a conserved core complex that associates with exoribonucleases and with multimeric cofactors that recruit the enzyme to its RNA targets. Despite an overall high level of structural and functional conservation, the enzymatic activities and compositions of exosome complexes and their cofactor modules differ among eukaryotes. This review highlights unique features of plant exosome complexes, such as the phosphorolytic activity of the core complex, and discusses the exosome cofactors that operate in plants and are dedicated to the maturation of ribosomal RNA, the elimination of spurious, misprocessed, and superfluous transcripts, or the removal of mRNAs cleaved by the RNA-induced silencing complex and other mRNAs prone to undergo silencing.
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Affiliation(s)
- Heike Lange
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
- Author for correspondence:
| | - Dominique Gagliardi
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
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17
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van Heuvel Y, Schatz S, Rosengarten JF, Stitz J. Infectious RNA: Human Immunodeficiency Virus (HIV) Biology, Therapeutic Intervention, and the Quest for a Vaccine. Toxins (Basel) 2022; 14:toxins14020138. [PMID: 35202165 PMCID: PMC8876946 DOI: 10.3390/toxins14020138] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/02/2022] [Accepted: 02/09/2022] [Indexed: 11/16/2022] Open
Abstract
Different mechanisms mediate the toxicity of RNA. Genomic retroviral mRNA hijacks infected host cell factors to enable virus replication. The viral genomic RNA of the human immunodeficiency virus (HIV) encompasses nine genes encoding in less than 10 kb all proteins needed for replication in susceptible host cells. To do so, the genomic RNA undergoes complex alternative splicing to facilitate the synthesis of the structural, accessory, and regulatory proteins. However, HIV strongly relies on the host cell machinery recruiting cellular factors to complete its replication cycle. Antiretroviral therapy (ART) targets different steps in the cycle, preventing disease progression to the acquired immunodeficiency syndrome (AIDS). The comprehension of the host immune system interaction with the virus has fostered the development of a variety of vaccine platforms. Despite encouraging provisional results in vaccine trials, no effective vaccine has been developed, yet. However, novel promising vaccine platforms are currently under investigation.
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Affiliation(s)
- Yasemin van Heuvel
- Research Group Pharmaceutical Biotechnology, Faculty of Applied Natural Sciences, TH Köln—University of Applied Sciences, Chempark Leverkusen, Kaiser-Wilhelm-Allee, 51368 Leverkusen, Germany; (Y.v.H.); (S.S.); (J.F.R.)
- Institute of Technical Chemistry, Leibniz University Hannover, Callinstraße 3-9, 30167 Hannover, Germany
| | - Stefanie Schatz
- Research Group Pharmaceutical Biotechnology, Faculty of Applied Natural Sciences, TH Köln—University of Applied Sciences, Chempark Leverkusen, Kaiser-Wilhelm-Allee, 51368 Leverkusen, Germany; (Y.v.H.); (S.S.); (J.F.R.)
- Institute of Technical Chemistry, Leibniz University Hannover, Callinstraße 3-9, 30167 Hannover, Germany
| | - Jamila Franca Rosengarten
- Research Group Pharmaceutical Biotechnology, Faculty of Applied Natural Sciences, TH Köln—University of Applied Sciences, Chempark Leverkusen, Kaiser-Wilhelm-Allee, 51368 Leverkusen, Germany; (Y.v.H.); (S.S.); (J.F.R.)
- Institute of Technical Chemistry, Leibniz University Hannover, Callinstraße 3-9, 30167 Hannover, Germany
| | - Jörn Stitz
- Research Group Pharmaceutical Biotechnology, Faculty of Applied Natural Sciences, TH Köln—University of Applied Sciences, Chempark Leverkusen, Kaiser-Wilhelm-Allee, 51368 Leverkusen, Germany; (Y.v.H.); (S.S.); (J.F.R.)
- Correspondence:
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18
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Pöll G, Pilsl M, Griesenbeck J, Tschochner H, Milkereit P. Analysis of subunit folding contribution of three yeast large ribosomal subunit proteins required for stabilisation and processing of intermediate nuclear rRNA precursors. PLoS One 2021; 16:e0252497. [PMID: 34813592 PMCID: PMC8610266 DOI: 10.1371/journal.pone.0252497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/17/2021] [Indexed: 11/19/2022] Open
Abstract
In yeast and human cells many of the ribosomal proteins (r-proteins) are required for the stabilisation and productive processing of rRNA precursors. Functional coupling of r-protein assembly with the stabilisation and maturation of subunit precursors potentially promotes the production of ribosomes with defined composition. To further decipher mechanisms of such an intrinsic quality control pathway we analysed here the contribution of three yeast large ribosomal subunit r-proteins rpL2 (uL2), rpL25 (uL23) and rpL34 (eL34) for intermediate nuclear subunit folding steps. Structure models obtained from single particle cryo-electron microscopy analyses provided evidence for specific and hierarchic effects on the stable positioning and remodelling of large ribosomal subunit domains. Based on these structural and previous biochemical data we discuss possible mechanisms of r-protein dependent hierarchic domain arrangement and the resulting impact on the stability of misassembled subunits.
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Affiliation(s)
- Gisela Pöll
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Michael Pilsl
- Structural Biochemistry Unit, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Joachim Griesenbeck
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
- * E-mail: (JG); (HT); (PM)
| | - Herbert Tschochner
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
- * E-mail: (JG); (HT); (PM)
| | - Philipp Milkereit
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
- * E-mail: (JG); (HT); (PM)
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19
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Lu YY, Krebber H. Nuclear mRNA Quality Control and Cytoplasmic NMD Are Linked by the Guard Proteins Gbp2 and Hrb1. Int J Mol Sci 2021; 22:ijms222011275. [PMID: 34681934 PMCID: PMC8541090 DOI: 10.3390/ijms222011275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 12/23/2022] Open
Abstract
Pre-mRNA splicing is critical for cells, as defects in this process can lead to altered open reading frames and defective proteins, potentially causing neurodegenerative diseases and cancer. Introns are removed in the nucleus and splicing is documented by the addition of exon-junction-complexes (EJCs) at exon-exon boundaries. This “memory” of splicing events is important for the ribosome, which translates the RNAs in the cytoplasm. In case a stop codon was detected before an EJC, translation is blocked and the RNA is eliminated by the nonsense-mediated decay (NMD). In the model organism Saccharomyces cerevisiae, two guard proteins, Gbp2 and Hrb1, have been identified as nuclear quality control factors for splicing. In their absence, intron-containing mRNAs leak into the cytoplasm. Their presence retains transcripts until the process is completed and they release the mRNAs by recruitment of the export factor Mex67. On transcripts that experience splicing problems, these guard proteins recruit the nuclear RNA degradation machinery. Interestingly, they continue their quality control function on exported transcripts. They support NMD by inhibiting translation and recruiting the cytoplasmic degradation factors. In this way, they link the nuclear and cytoplasmic quality control systems. These discoveries are also intriguing for humans, as homologues of these guard proteins are present also in multicellular organisms. Here, we provide an overview of the quality control mechanisms of pre-mRNA splicing, and present Gbp2 and Hrb1, as well as their human counterparts, as important players in these pathways.
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20
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Dendooven T, Paris G, Shkumatov AV, Islam MS, Burt A, Kubańska MA, Yang TY, Hardwick SW, Luisi BF. Multi-scale ensemble properties of the Escherichia coli RNA degradosome. Mol Microbiol 2021; 117:102-120. [PMID: 34415624 PMCID: PMC7613265 DOI: 10.1111/mmi.14800] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/09/2021] [Accepted: 08/18/2021] [Indexed: 11/30/2022]
Abstract
In organisms from all domains of life, multi-enzyme assemblies play central roles in defining transcript lifetimes and facilitating RNA-mediated regulation of gene expression. An assembly dedicated to such roles, known as the RNA degradosome, is found amongst bacteria from highly diverse lineages. About a fifth of the assembly mass of the degradosome of Escherichia coli and related species is predicted to be intrinsically disordered - a property that has been sustained for over a billion years of bacterial molecular history and stands in marked contrast to the high degree of sequence variation of that same region. Here, we characterize the conformational dynamics of the degradosome using a hybrid structural biology approach that combines solution scattering with ad hoc ensemble modelling, cryo-electron microscopy, and other biophysical methods. The E. coli degradosome can form punctate bodies in vivo that may facilitate its functional activities, and based on our results, we propose an electrostatic switch model to account for the propensity of the degradosome to undergo programmable puncta formation.
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Affiliation(s)
- Tom Dendooven
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Giulia Paris
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alexander V Shkumatov
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Md Saiful Islam
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alister Burt
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Marta A Kubańska
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Tai Yuchen Yang
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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21
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Jara-Espejo M, Hawkins MTR, Fogalli GB, Line SRP. Folding Stability of Pax9 Intronic G-Quadruplex Correlates with Relative Molar Size in Eutherians. Mol Biol Evol 2021; 38:1860-1873. [PMID: 33355664 PMCID: PMC8097303 DOI: 10.1093/molbev/msaa331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Eutherian dentition has been the focus of a great deal of studies in the areas of evolution, development, and genomics. The development of molar teeth is regulated by an antero-to-posterior cascade mechanism of activators and inhibitors molecules, where the relative sizes of the second (M2) and third (M3) molars are dependent of the inhibitory influence of the first molar (M1). Higher activator/inhibitor ratios will result in higher M2/M1 or M3/M1. Pax9 has been shown to play a key role in tooth development. We have previously shown that a G-quadruplex in the first intron of Pax9 can modulate the splicing efficiency. Using a sliding window approach with we analyzed the association of the folding energy (Mfe) of the Pax9 first intron with the relative molar sizes in 42 mammalian species, representing 9 orders. The Mfe of two regions located in the first intron of Pax9 were shown to be significantly associated with the M2/M1 and M3/M1 areas and mesiodistal lengths. The first region is located at the intron beginning and can fold into a stable G4 structure, whereas the second is downstream the G4 and 265 bp from intron start. Across species, the first intron of Pax9 varied in G-quadruplex structural stability. The correlations were further increased when the Mfe of the two sequences were added. Our results indicate that this region has a role in the evolution of the mammalian dental pattern by influencing the relative size of the molars.
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Affiliation(s)
- Manuel Jara-Espejo
- Department of Biosciences, Piracicaba Dental School, University of Campinas, Brazil
| | - Melissa T R Hawkins
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
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22
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An introduction to the themed issue on RNA biology in China. Essays Biochem 2021; 64:863-866. [PMID: 33284952 DOI: 10.1042/ebc20200031] [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: 09/13/2020] [Revised: 10/25/2020] [Accepted: 11/02/2020] [Indexed: 11/17/2022]
Abstract
The year 2019 marked the fortieth anniversary of the Chinese Society of Biochemistry and Molecular Biology (CSBMB), whose mission is to promote biomolecular research and education in China. The last 40 years have witnessed tremendous growth and achievements in biomolecular research by Chinese scientists and Essays in Biochemistry is delighted to publish this themed issue that focuses on exciting areas within RNA biology, with each review contributed by key experts from China.
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23
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Das M, Zattas D, Zinder JC, Wasmuth EV, Henri J, Lima CD. Substrate discrimination and quality control require each catalytic activity of TRAMP and the nuclear RNA exosome. Proc Natl Acad Sci U S A 2021; 118:e2024846118. [PMID: 33782132 PMCID: PMC8040639 DOI: 10.1073/pnas.2024846118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quality control requires discrimination between functional and aberrant species to selectively target aberrant substrates for destruction. Nuclear RNA quality control in Saccharomyces cerevisiae includes the TRAMP complex that marks RNA for decay via polyadenylation followed by helicase-dependent 3' to 5' degradation by the RNA exosome. Using reconstitution biochemistry, we show that polyadenylation and helicase activities of TRAMP cooperate with processive and distributive exoribonuclease activities of the nuclear RNA exosome to protect stable RNA from degradation while selectively targeting and degrading less stable RNA. Substrate discrimination is lost when the distributive exoribonuclease activity of Rrp6 is inactivated, leading to degradation of stable and unstable RNA species. These data support a proofreading mechanism in which deadenylation by Rrp6 competes with Mtr4-dependent degradation to protect stable RNA while selectively targeting and degrading unstable RNA.
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Affiliation(s)
- Mom Das
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Dimitrios Zattas
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - John C Zinder
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Elizabeth V Wasmuth
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Julien Henri
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065;
- HHMI, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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24
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Abstract
The subcellular localization of RNAs correlates with their function and how they are regulated. Most protein-coding mRNAs are exported into the cytoplasm for protein synthesis, while some mRNA species, long noncoding RNAs, and some regulatory element-associated unstable transcripts tend to be retained in the nucleus, where they function as a regulatory unit and/or are regulated by nuclear surveillance pathways. While the mechanisms regulating mRNA export and localization have been well summarized, the mechanisms governing nuclear retention of RNAs, especially of noncoding RNAs, are seldomly reviewed. In this review, we summarize recent advances in the mechanistic study of RNA nuclear retention, especially for noncoding RNAs, from the angle of cis-acting elements embedded in RNA transcripts and their interaction with trans-acting factors. We also try to illustrate the general principles of RNA nuclear retention and we discuss potential areas for future investigation.
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Affiliation(s)
- Chong Tong
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yafei Yin
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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25
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Wei FJ, Ueno S, Ujino-Ihara T, Saito M, Tsumura Y, Higuchi Y, Hirayama S, Iwai J, Hakamata T, Moriguchi Y. Construction of a reference transcriptome for the analysis of male sterility in sugi (Cryptomeria japonica D. Don) focusing on MALE STERILITY 1 (MS1). PLoS One 2021; 16:e0247180. [PMID: 33630910 PMCID: PMC7935350 DOI: 10.1371/journal.pone.0247180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 02/02/2021] [Indexed: 11/18/2022] Open
Abstract
Sugi (Cryptomeria japonica D. Don) is an important conifer used for afforestation in Japan. As the genome of this species is 11 Gbps, it is too large to assemble within a short timeframe. Transcriptomics is one approach that can address this deficiency. Here we designed a workflow consisting of three stages to de novo assemble transcriptome using Oases and Trinity. The three transcriptomic stage used were independent assembly, automatic and semi-manual integration, and refinement by filtering out potential contamination. We identified a set of 49,795 cDNA and an equal number of translated proteins. According to the benchmark set by BUSCO, 87.01% of cDNAs identified were complete genes, and 78.47% were complete and single-copy genes. Compared to other full-length cDNA resources collected by Sanger and PacBio sequencers, the extent of the coverage in our dataset was the highest, indicating that these data can be safely used for further studies. When two tissue-specific libraries were compared, there were significant expression differences between male strobili and leaf and bark sets. Moreover, subtle expression difference between male-fertile and sterile libraries were detected. Orthologous genes from other model plants and conifer species were identified. We demonstrated that our transcriptome assembly output (CJ3006NRE) can serve as a reference transcriptome for future functional genomics and evolutionary biology studies.
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Affiliation(s)
- Fu-Jin Wei
- Forestry and Forest Products Research Institute, Forest Research and Management Organization, Ibaraki, Japan
| | - Saneyoshi Ueno
- Forestry and Forest Products Research Institute, Forest Research and Management Organization, Ibaraki, Japan
- * E-mail:
| | - Tokuko Ujino-Ihara
- Forestry and Forest Products Research Institute, Forest Research and Management Organization, Ibaraki, Japan
| | - Maki Saito
- Forest Research Institute, Toyama Prefectural Agricultural Forestry and Fisheries Research Center, Toyama, Japan
| | - Yoshihiko Tsumura
- Forestry and Forest Products Research Institute, Forest Research and Management Organization, Ibaraki, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Yuumi Higuchi
- Niigata Prefectural Forest Research Institute, Niigata, Japan
| | | | - Junji Iwai
- Niigata Prefectural Forest Research Institute, Niigata, Japan
| | - Tetsuji Hakamata
- Shizuoka Prefectural Research Institute of Agriculture and Forestry, Shizuoka, Japan
| | - Yoshinari Moriguchi
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
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26
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Aguilar LC, Paul B, Reiter T, Gendron L, Arul Nambi Rajan A, Montpetit R, Trahan C, Pechmann S, Oeffinger M, Montpetit B. Altered rRNA processing disrupts nuclear RNA homeostasis via competition for the poly(A)-binding protein Nab2. Nucleic Acids Res 2020; 48:11675-11694. [PMID: 33137177 PMCID: PMC7672433 DOI: 10.1093/nar/gkaa964] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/06/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
RNA-binding proteins (RBPs) are key mediators of RNA metabolism. Whereas some RBPs exhibit narrow transcript specificity, others function broadly across both coding and non-coding RNAs. Here, in Saccharomyces cerevisiae, we demonstrate that changes in RBP availability caused by disruptions to distinct cellular processes promote a common global breakdown in RNA metabolism and nuclear RNA homeostasis. Our data shows that stabilization of aberrant ribosomal RNA (rRNA) precursors in an enp1-1 mutant causes phenotypes similar to RNA exosome mutants due to nucleolar sequestration of the poly(A)-binding protein (PABP) Nab2. Decreased nuclear PABP availability is accompanied by genome-wide changes in RNA metabolism, including increased pervasive transcripts levels and snoRNA processing defects. These phenotypes are mitigated by overexpression of PABPs, inhibition of rDNA transcription, or alterations in TRAMP activity. Our results highlight the need for cells to maintain poly(A)-RNA levels in balance with PABPs and other RBPs with mutable substrate specificity across nucleoplasmic and nucleolar RNA processes.
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Affiliation(s)
- Lisbeth-Carolina Aguilar
- Department for Systems Biology, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada
| | - Biplab Paul
- Department of Cell Biology, University of Alberta, Edmonton, Canada
| | - Taylor Reiter
- Food Science Graduate Group, University of California Davis, Davis, CA, USA
| | - Louis Gendron
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Arvind Arul Nambi Rajan
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, CA, USA
| | - Rachel Montpetit
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Christian Trahan
- Department for Systems Biology, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada
| | - Sebastian Pechmann
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Marlene Oeffinger
- Department for Systems Biology, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, QC, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Canada
- Food Science Graduate Group, University of California Davis, Davis, CA, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, CA, USA
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
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27
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Zhang Y, Kuster D, Schmidt T, Kirrmaier D, Nübel G, Ibberson D, Benes V, Hombauer H, Knop M, Jäschke A. Extensive 5'-surveillance guards against non-canonical NAD-caps of nuclear mRNAs in yeast. Nat Commun 2020; 11:5508. [PMID: 33139726 PMCID: PMC7606564 DOI: 10.1038/s41467-020-19326-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 09/24/2020] [Indexed: 12/16/2022] Open
Abstract
The ubiquitous redox coenzyme nicotinamide adenine dinucleotide (NAD) acts as a non-canonical cap structure on prokaryotic and eukaryotic ribonucleic acids. Here we find that in budding yeast, NAD-RNAs are abundant (>1400 species), short (<170 nt), and mostly correspond to mRNA 5′-ends. The modification percentage of transcripts is low (<5%). NAD incorporation occurs mainly during transcription initiation by RNA polymerase II, which uses distinct promoters with a YAAG core motif for this purpose. Most NAD-RNAs are 3′-truncated. At least three decapping enzymes, Rai1, Dxo1, and Npy1, guard against NAD-RNA at different cellular locations, targeting overlapping transcript populations. NAD-mRNAs are not translatable in vitro. Our work indicates that in budding yeast, most of the NAD incorporation into RNA seems to be disadvantageous to the cell, which has evolved a diverse surveillance machinery to prematurely terminate, decap and reject NAD-RNAs. NAD (nicotinamide adenine dinucleotide) acts as a non-canonical RNA cap structure in bacteria and eukaryotes. Here the authors demonstrate the whole landscape of budding yeast NAD-RNAs which are subject to diverse surveillance pathways, suggesting that NAD caps in budding yeast are mostly dysfunctional.
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Affiliation(s)
- Yaqing Zhang
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, 69120, Heidelberg, Germany
| | - David Kuster
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, 69120, Heidelberg, Germany
| | - Tobias Schmidt
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Daniel Kirrmaier
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, 69120, Heidelberg, Germany.,Cell Morphogenesis and Signal Transduction, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
| | - Gabriele Nübel
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, 69120, Heidelberg, Germany
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks, Heidelberg University, 69120, Heidelberg, Germany
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL), 69117, Heidelberg, Germany
| | - Hans Hombauer
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, 69120, Heidelberg, Germany
| | - Michael Knop
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, 69120, Heidelberg, Germany.,Cell Morphogenesis and Signal Transduction, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, 69120, Heidelberg, Germany.
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28
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Bursać S, Prodan Y, Pullen N, Bartek J, Volarević S. Dysregulated Ribosome Biogenesis Reveals Therapeutic Liabilities in Cancer. Trends Cancer 2020; 7:57-76. [PMID: 32948502 DOI: 10.1016/j.trecan.2020.08.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 12/24/2022]
Abstract
Ribosome biogenesis (RiBi) is one of the most complex and energy demanding processes in human cells, critical for cell growth and proliferation. Strong causal links between inherited and acquired impairment in RiBi with cancer pathogenesis are emerging, pointing to RiBi as an attractive therapeutic target for cancer. Here, we will highlight new knowledge about causes of excessive or impaired RiBi and the impact of these changes on protein synthesis. We will also discuss how new knowledge about secondary consequences of dysregulated RiBi and protein synthesis, including proteotoxic stress, metabolic alterations, adaptive transcriptional and translational programs, and the impaired ribosome biogenesis checkpoint (IRBC) provide a foundation for the development of new anticancer therapies.
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Affiliation(s)
- Slađana Bursać
- Department of Molecular Medicine and Biotechnology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia
| | - Ylenia Prodan
- Department of Molecular Medicine and Biotechnology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia
| | - Nick Pullen
- Bristol Myers Squibb, 200 Cambridge Park Drive, Cambridge, MA 02140, USA
| | - Jiri Bartek
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, 171 76, Stockholm, Sweden; The Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark.
| | - Siniša Volarević
- Department of Molecular Medicine and Biotechnology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia.
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29
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Gales JP, Kubina J, Geldreich A, Dimitrova M. Strength in Diversity: Nuclear Export of Viral RNAs. Viruses 2020; 12:E1014. [PMID: 32932882 PMCID: PMC7551171 DOI: 10.3390/v12091014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 12/11/2022] Open
Abstract
The nuclear export of cellular mRNAs is a complex process that requires the orchestrated participation of many proteins that are recruited during the early steps of mRNA synthesis and processing. This strategy allows the cell to guarantee the conformity of the messengers accessing the cytoplasm and the translation machinery. Most transcripts are exported by the exportin dimer Nuclear RNA export factor 1 (NXF1)-NTF2-related export protein 1 (NXT1) and the transcription-export complex 1 (TREX1). Some mRNAs that do not possess all the common messenger characteristics use either variants of the NXF1-NXT1 pathway or CRM1, a different exportin. Viruses whose mRNAs are synthesized in the nucleus (retroviruses, the vast majority of DNA viruses, and influenza viruses) exploit both these cellular export pathways. Viral mRNAs hijack the cellular export machinery via complex secondary structures recognized by cellular export factors and/or viral adapter proteins. This way, the viral transcripts succeed in escaping the host surveillance system and are efficiently exported for translation, allowing the infectious cycle to proceed. This review gives an overview of the cellular mRNA nuclear export mechanisms and presents detailed insights into the most important strategies that viruses use to export the different forms of their RNAs from the nucleus to the cytoplasm.
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Affiliation(s)
- Jón Pol Gales
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
| | - Julie Kubina
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
- SVQV UMR-A 1131, INRAE, Université de Strasbourg, F-68000 Colmar, France
| | - Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
| | - Maria Dimitrova
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
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30
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Arunkumar G, Melters DP. Centromeric Transcription: A Conserved Swiss-Army Knife. Genes (Basel) 2020; 11:E911. [PMID: 32784923 PMCID: PMC7463856 DOI: 10.3390/genes11080911] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
In most species, the centromere is comprised of repetitive DNA sequences, which rapidly evolve. Paradoxically, centromeres fulfill an essential function during mitosis, as they are the chromosomal sites wherein, through the kinetochore, the mitotic spindles bind. It is now generally accepted that centromeres are transcribed, and that such transcription is associated with a broad range of functions. More than a decade of work on this topic has shown that centromeric transcripts are found across the eukaryotic tree and associate with heterochromatin formation, chromatin structure, kinetochore structure, centromeric protein loading, and inner centromere signaling. In this review, we discuss the conservation of small and long non-coding centromeric RNAs, their associations with various centromeric functions, and their potential roles in disease.
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Affiliation(s)
| | - Daniël P. Melters
- Chromatin Structure and Epigenetic Mechanisms, Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA;
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31
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32
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Kaposi's Sarcoma-Associated Herpesvirus Fine-Tunes the Temporal Expression of Late Genes by Manipulating a Host RNA Quality Control Pathway. J Virol 2020; 94:JVI.00287-20. [PMID: 32376621 DOI: 10.1128/jvi.00287-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/28/2020] [Indexed: 12/25/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a human oncogenic nuclear DNA virus that expresses its genes using the host cell transcription and RNA processing machinery. As a result, KSHV transcripts are subject to degradation by at least two host-mediated nuclear RNA decay pathways, the PABPN1- and poly(A) polymerase α/γ (PAPα/γ)-mediated RNA decay (PPD) pathway and an ARS2-dependent decay pathway. Here, we present global analyses of viral transcript levels to further understand the roles of these decay pathways in KSHV gene expression. Consistent with our recent report that the KSHV ORF57 protein increases viral transcript stability by impeding ARS2-dependent decay, ARS2 knockdown has only modest effects on viral gene expression 24 h after lytic reactivation of wild-type virus. In contrast, inactivation of PPD has more widespread effects, including premature accumulation of late transcripts. The upregulation of late transcripts does not require the primary late-gene-specific viral transactivation factor, suggesting that cryptic transcription produces the transcripts that then succumb to PPD. Remarkably, PPD inactivation has no effect on late transcripts at their proper time of expression. We show that this time-dependent PPD evasion by late transcripts requires the host factor nuclear RNAi-defective 2 (NRDE2), which has previously been reported to protect cellular RNAs by sequestering decay factors. From these studies, we conclude that KSHV uses PPD to fine-tune the temporal expression of its genes by preventing their premature accumulation.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus that causes Kaposi's sarcoma and other lymphoproliferative disorders. Nuclear expression of KSHV genes results in exposure to at least two host-mediated nuclear RNA decay pathways, the PABPN1- and PAPα/γ-mediated RNA decay (PPD) pathway and an ARS2-mediated decay pathway. Perhaps unsurprisingly, we previously found that KSHV uses specific mechanisms to protect its transcripts from ARS2-mediated decay. In contrast, here we show that PPD is required to dampen the expression of viral late transcripts that are prematurely transcribed, presumably due to cryptic transcription early in infection. At the proper time for their expression, KSHV late transcripts evade PPD through the activity of the host factor NRDE2. We conclude that KSHV fine-tunes the temporal expression of its genes by modulating PPD activity. Thus, the virus both protects from and exploits the host nuclear RNA decay machinery for proper expression of its genes.
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33
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Delan-Forino C, Spanos C, Rappsilber J, Tollervey D. Substrate specificity of the TRAMP nuclear surveillance complexes. Nat Commun 2020; 11:3122. [PMID: 32561742 PMCID: PMC7305330 DOI: 10.1038/s41467-020-16965-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 05/29/2020] [Indexed: 01/01/2023] Open
Abstract
During nuclear surveillance in yeast, the RNA exosome functions together with the TRAMP complexes. These include the DEAH-box RNA helicase Mtr4 together with an RNA-binding protein (Air1 or Air2) and a poly(A) polymerase (Trf4 or Trf5). To better determine how RNA substrates are targeted, we analyzed protein and RNA interactions for TRAMP components. Mass spectrometry identified three distinct TRAMP complexes formed in vivo. These complexes preferentially assemble on different classes of transcripts. Unexpectedly, on many substrates, including pre-rRNAs and pre-mRNAs, binding specificity is apparently conferred by Trf4 and Trf5. Clustering of mRNAs by TRAMP association shows co-enrichment for mRNAs with functionally related products, supporting the significance of surveillance in regulating gene expression. We compared binding sites of TRAMP components with multiple nuclear RNA binding proteins, revealing preferential colocalization of subsets of factors. TRF5 deletion reduces Mtr4 recruitment and increases RNA abundance for mRNAs specifically showing high Trf5 binding.
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Affiliation(s)
- Clémentine Delan-Forino
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
| | - Christos Spanos
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
| | - Juri Rappsilber
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355, Berlin, Germany
| | - David Tollervey
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK.
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34
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Turowski TW, Tollervey D. Extended ncRNAs Interfere with Promoter Nucleosome Dynamics. Trends Genet 2020; 36:637-639. [PMID: 32546405 DOI: 10.1016/j.tig.2020.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 10/24/2022]
Abstract
Eukaryotic genomes generate vast numbers of non-protein-coding RNAs (ncRNAs) that can inhibit mRNA synthesis through transcription interference, but the mechanisms are unclear. Gill et al. show that transcription of antisense ncRNAs induces 'elongation marks' on histones in promoter regions. These inhibit active nucleosome positioning required to maintain open transcription-initiation sites.
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Affiliation(s)
- Tomasz W Turowski
- Wellcome Centre for Cell Biology, The University of Edinburgh, Edinburgh, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology, The University of Edinburgh, Edinburgh, UK.
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35
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Elrod ND, Henriques T, Huang KL, Tatomer DC, Wilusz JE, Wagner EJ, Adelman K. The Integrator Complex Attenuates Promoter-Proximal Transcription at Protein-Coding Genes. Mol Cell 2020; 76:738-752.e7. [PMID: 31809743 DOI: 10.1016/j.molcel.2019.10.034] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/15/2019] [Accepted: 10/25/2019] [Indexed: 12/11/2022]
Abstract
The transition of RNA polymerase II (Pol II) from initiation to productive elongation is a central, regulated step in metazoan gene expression. At many genes, Pol II pauses stably in early elongation, remaining engaged with the 25- to 60-nt-long nascent RNA for many minutes while awaiting signals for release into the gene body. However, 15%-20% of genes display highly unstable promoter Pol II, suggesting that paused polymerase might dissociate from template DNA at these promoters and release a short, non-productive mRNA. Here, we report that paused Pol II can be actively destabilized by the Integrator complex. Specifically, we present evidence that Integrator utilizes its RNA endonuclease activity to cleave nascent RNA and drive termination of paused Pol II. These findings uncover a previously unappreciated mechanism of metazoan gene repression, akin to bacterial transcription attenuation, wherein promoter-proximal Pol II is prevented from entering productive elongation through factor-regulated termination.
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Affiliation(s)
- Nathan D Elrod
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Telmo Henriques
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Kai-Lieh Huang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Deirdre C Tatomer
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA.
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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36
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Stolyarenko AD. Nuclear Argonaute Piwi Gene Mutation Affects rRNA by Inducing rRNA Fragment Accumulation, Antisense Expression, and Defective Processing in Drosophila Ovaries. Int J Mol Sci 2020; 21:ijms21031119. [PMID: 32046213 PMCID: PMC7037970 DOI: 10.3390/ijms21031119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/27/2020] [Accepted: 02/04/2020] [Indexed: 12/26/2022] Open
Abstract
Drosophila key nuclear piRNA silencing pathway protein Piwi of the Argonaute family has been classically studied as a factor controlling transposable elements and fertility. Piwi has been shown to concentrate in the nucleolus for reasons largely unknown. Ribosomal RNA is the main component of the nucleolus. In this work the effect of a piwi mutation on rRNA is described. This work led to three important conclusions: A mutation in piwi induces antisense 5S rRNA expression, a processing defect of 2S rRNA orthologous to the 3′-end of eukaryotic 5.8S rRNA, and accumulation of fragments of all five rRNAs in Drosophilamelanogaster ovaries. Hypotheses to explain these phenomena are proposed, possibly involving the interaction of the components of the piRNA pathway with the RNA surveillance machinery.
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Affiliation(s)
- Anastasia D Stolyarenko
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., Moscow 123182, Russia
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37
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Meiotic gene silencing complex MTREC/NURS recruits the nuclear exosome to YTH-RNA-binding protein Mmi1. PLoS Genet 2020; 16:e1008598. [PMID: 32012158 PMCID: PMC7018101 DOI: 10.1371/journal.pgen.1008598] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 02/13/2020] [Accepted: 01/03/2020] [Indexed: 11/24/2022] Open
Abstract
Accurate target recognition in transcript degradation is crucial for regulation of gene expression. In the fission yeast Schizosaccharomyces pombe, a number of meiotic transcripts are recognized by a YTH-family RNA-binding protein, Mmi1, and selectively degraded by the nuclear exosome during mitotic growth. Mmi1 forms nuclear foci in mitotically growing cells, and the nuclear exosome colocalizes to such foci. However, it remains elusive how Mmi1 and the nuclear exosome are connected. Here, we show that a complex called MTREC (Mtl1-Red1 core) or NURS (nuclear RNA silencing) that consists of a zinc-finger protein, Red1, and an RNA helicase, Mtl1, is required for the recruitment of the nuclear exosome to Mmi1 foci. Physical interaction between Mmi1 and the nuclear exosome depends on Red1. Furthermore, a chimeric protein involving Mmi1 and Rrp6, which is a nuclear-specific component of the exosome, suppresses the ectopic expression phenotype of meiotic transcripts in red1Δ cells and mtl1 mutant cells. These data indicate that the primary function of MTREC/NURS in meiotic transcript elimination is to link Mmi1 to the nuclear exosome physically. Since abnormal gene expression is detrimental to proliferation, cells possess a number of mechanisms to regulate gene expression at transcriptional and post-transcriptional levels. In particular, expression of meiotic genes is rigorously repressed in somatic cells because their aberrant expression causes severe cellular defects including genome instability and tumorigenesis. In the fission yeast Schizosaccharomyces pombe, selective degradation of meiotic transcripts is employed to prevent their deleterious expression during mitotic growth. Meiotic transcripts are recognized by a YTH-family RNA-binding protein, Mmi1. Mmi1 then induces their selective degradation by the nuclear exosome, which is a highly conserved exonuclease complex. However, little is known how Mmi1 cooperates with the nuclear exosome. Here, we demonstrate that the interaction of Mmi1 with the nuclear exosome is mediated by a complex termed MTREC/NURS that is composed of a conserved zinc-finger protein, Red1, and an RNA helicase, Mtl1. Our findings shed light on the target recognition mechanisms of post-transcriptional regulation.
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38
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Kainov YA, Makeyev EV. A transcriptome-wide antitermination mechanism sustaining identity of embryonic stem cells. Nat Commun 2020; 11:361. [PMID: 31953406 PMCID: PMC6969169 DOI: 10.1038/s41467-019-14204-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 12/11/2019] [Indexed: 11/29/2022] Open
Abstract
Eukaryotic gene expression relies on extensive crosstalk between transcription and RNA processing. Changes in this composite regulation network may provide an important means for shaping cell type-specific transcriptomes. Here we show that the RNA-associated protein Srrt/Ars2 sustains embryonic stem cell (ESC) identity by preventing premature termination of numerous transcripts at cryptic cleavage/polyadenylation sites in first introns. Srrt interacts with the nuclear cap-binding complex and facilitates recruitment of the spliceosome component U1 snRNP to cognate intronic positions. At least in some cases, U1 recruited in this manner inhibits downstream cleavage/polyadenylation events through a splicing-independent mechanism called telescripting. We further provide evidence that the naturally high expression of Srrt in ESCs offsets deleterious effects of retrotransposable sequences accumulating in its targets. Our work identifies Srrt as a molecular guardian of the pluripotent cell state. Besides its role in splicing, U1 snRNP can suppress pre-mRNA cleavage and polyadenylation. The authors show that the nuclear cap-binding complex component Srrt/Ars2 maintains embryonic stem cell identity by promoting U1 recruitment to first introns and preventing premature termination of multiple transcripts.
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Affiliation(s)
- Yaroslav A Kainov
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
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39
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Hsu PJ, Shi H, Zhu AC, Lu Z, Miller N, Edens BM, Ma YC, He C. The RNA-binding protein FMRP facilitates the nuclear export of N6-methyladenosine-containing mRNAs. J Biol Chem 2019; 294:19889-19895. [PMID: 31753916 PMCID: PMC6937581 DOI: 10.1074/jbc.ac119.010078] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 11/20/2019] [Indexed: 11/06/2022] Open
Abstract
N6-Methyladenosine (m6A) is the most abundant post-transcriptional mRNA modification in eukaryotes and exerts many of its effects on gene expression through reader proteins that bind specifically to m6A-containing transcripts. Fragile X mental retardation protein (FMRP), an RNA-binding protein, has previously been shown to affect the translation of target mRNAs and trafficking of mRNA granules. Loss of function of FMRP causes fragile X syndrome, the most common form of inherited intellectual disability in humans. Using HEK293T cells, siRNA-mediated gene knockdown, cytoplasmic and nuclear fractions, RNA-Seq, and LC-MS/MS analyses, we demonstrate here that FMRP binds directly to a collection of m6A sites on mRNAs. FMRP depletion increased mRNA m6A levels in the nucleus. Moreover, the abundance of FMRP targets in the cytoplasm relative to the nucleus was decreased in Fmr1-KO mice, an effect also observed in highly methylated genes. We conclude that FMRP may affect the nuclear export of m6A-modified RNA targets.
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Affiliation(s)
- Phillip J Hsu
- Department of Chemistry and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
- Medical Scientist Training Program/Committee on Immunology, University of Chicago, Chicago, Illinois 60637
| | - Hailing Shi
- Department of Chemistry and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
| | - Allen C Zhu
- Department of Chemistry and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
- Medical Scientist Training Program/Committee on Cancer Biology, University of Chicago, Chicago, Illinois 60637
| | - Zhike Lu
- Department of Chemistry and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
| | - Nimrod Miller
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Anne and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois 60611
| | - Brittany M Edens
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Anne and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois 60611
| | - Yongchao C Ma
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Anne and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois 60611
| | - Chuan He
- Department of Chemistry and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637
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40
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Abstract
The exoribonuclease Rrp6p is critical for RNA decay in the nucleus. While Rrp6p acts on a large range of diverse substrates, it does not indiscriminately degrade all RNAs. How Rrp6p accomplishes this task is not understood. Here, we measure Rrp6p-RNA binding and degradation kinetics in vitro at single-nucleotide resolution and find an intrinsic substrate selectivity that enables Rrp6p to discriminate against specific RNAs. RNA length and the four 3'-terminal nucleotides contribute most to substrate selectivity and collectively enable Rrp6p to discriminate between different RNAs by several orders of magnitude. The most pronounced discrimination is seen against RNAs ending with CCA-3'. These RNAs correspond to 3' termini of uncharged tRNAs, which are not targeted by Rrp6p in cells. The data show that in contrast to many other proteins that use substrate selectivity to preferentially interact with specific RNAs, Rrp6p utilizes its selectivity to discriminate against specific RNAs. This ability allows Rrp6p to target diverse substrates while avoiding a subset of RNAs.
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41
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Dendooven T, Luisi BF, Bandyra KJ. RNA lifetime control, from stereochemistry to gene expression. Curr Opin Struct Biol 2019; 61:59-70. [PMID: 31869589 DOI: 10.1016/j.sbi.2019.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 10/25/2022]
Abstract
Through the activities of various multi-component assemblies, protein-coding transcripts can be chaperoned toward protein synthesis or nudged into a funnel of rapid destruction. The capacity of these machine-like assemblies to tune RNA lifetime underpins the harmony of gene expression in all cells. Some of the molecular machines that mediate transcript turnover also contribute to on-the-fly surveillance of aberrant mRNAs and non-coding RNAs. How these dynamic assemblies distinguish functional RNAs from those that must be degraded is an intriguing puzzle for understanding the regulation of gene expression and dysfunction associated with disease. Recent data illuminate what the machines look like, and how they find, recognise and operate on transcripts to sculpt the dynamic regulatory landscape. This review captures current structural and mechanistic insights into the key enzymes and their effector assemblies that contribute to the fate-determining decision points for RNA in post-transcriptional control of genetic information.
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Affiliation(s)
- Tom Dendooven
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.
| | - Katarzyna J Bandyra
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.
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42
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Martín‐Expósito M, Gas M, Mohamad N, Nuño‐Cabanes C, Tejada‐Colón A, Pascual‐García P, de la Fuente L, Chaves‐Arquero B, Merran J, Corden J, Conesa A, Pérez‐Cañadillas JM, Bravo J, Rodríguez‐Navarro S. Mip6 binds directly to the Mex67 UBA domain to maintain low levels of Msn2/4 stress-dependent mRNAs. EMBO Rep 2019; 20:e47964. [PMID: 31680439 PMCID: PMC6893359 DOI: 10.15252/embr.201947964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 08/30/2019] [Accepted: 09/11/2019] [Indexed: 11/09/2022] Open
Abstract
RNA-binding proteins (RBPs) participate in all steps of gene expression, underscoring their potential as regulators of RNA homeostasis. We structurally and functionally characterize Mip6, a four-RNA recognition motif (RRM)-containing RBP, as a functional and physical interactor of the export factor Mex67. Mip6-RRM4 directly interacts with the ubiquitin-associated (UBA) domain of Mex67 through a loop containing tryptophan 442. Mip6 shuttles between the nucleus and the cytoplasm in a Mex67-dependent manner and concentrates in cytoplasmic foci under stress. Photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation experiments show preferential binding of Mip6 to mRNAs regulated by the stress-response Msn2/4 transcription factors. Consistent with this binding, MIP6 deletion affects their export and expression levels. Additionally, Mip6 interacts physically and/or functionally with proteins with a role in mRNA metabolism and transcription such as Rrp6, Xrn1, Sgf73, and Rpb1. These results reveal a novel role for Mip6 in the homeostasis of Msn2/4-dependent transcripts through its direct interaction with the Mex67 UBA domain.
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Grants
- BFU2014-57636 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- BFU2015-71978 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- SAF2015-67077-R Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- SAF2017-89901-R Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- CTQ2018-84371 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- PGC2018-099872-B-I00 Ministerio de Ciencia, Innovación y Universidades (Ministry of Science, Innovation and Universities)
- PROM/2012/061 Generalitat Valenciana (Regional Government of Valencia)
- PROMETEO 2016/093 Generalitat Valenciana (Regional Government of Valencia)
- ACOMP2014/061 Generalitat Valenciana (Regional Government of Valencia)
- B2017/BMD-3770 Comunidad de Madrid (Madrid Autonomous Community)
- Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- Comunidad de Madrid (Madrid Autonomous Community)
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Affiliation(s)
- Manuel Martín‐Expósito
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Maria‐Eugenia Gas
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Nada Mohamad
- Signal Transduction LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
| | - Carme Nuño‐Cabanes
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Ana Tejada‐Colón
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
| | - Pau Pascual‐García
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
- Present address:
Department of Cell and Developmental BiologyEpigenetics InstitutePerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Lorena de la Fuente
- Genomics of Gene Expression LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Belén Chaves‐Arquero
- Department of Biological Physical ChemistryInstitute of Physical‐Chemistry “Rocasolano” (CSIC)MadridSpain
| | - Jonathan Merran
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Jeffry Corden
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Ana Conesa
- Genetics InstituteUniversity of FloridaGainesvilleFLUSA
- Microbiology and Cell Science DepartmentInstitute for Food and Agricultural ResearchUniversity of FloridaGainesvilleFLUSA
| | | | - Jerónimo Bravo
- Signal Transduction LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
| | - Susana Rodríguez‐Navarro
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
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43
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Elrod ND, Henriques T, Huang KL, Tatomer DC, Wilusz JE, Wagner EJ, Adelman K. The Integrator Complex Attenuates Promoter-Proximal Transcription at Protein-Coding Genes. Mol Cell 2019; 76:738-752.e7. [PMID: 31809743 DOI: 10.1101/725507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/15/2019] [Accepted: 10/25/2019] [Indexed: 05/27/2023]
Abstract
The transition of RNA polymerase II (Pol II) from initiation to productive elongation is a central, regulated step in metazoan gene expression. At many genes, Pol II pauses stably in early elongation, remaining engaged with the 25- to 60-nt-long nascent RNA for many minutes while awaiting signals for release into the gene body. However, 15%-20% of genes display highly unstable promoter Pol II, suggesting that paused polymerase might dissociate from template DNA at these promoters and release a short, non-productive mRNA. Here, we report that paused Pol II can be actively destabilized by the Integrator complex. Specifically, we present evidence that Integrator utilizes its RNA endonuclease activity to cleave nascent RNA and drive termination of paused Pol II. These findings uncover a previously unappreciated mechanism of metazoan gene repression, akin to bacterial transcription attenuation, wherein promoter-proximal Pol II is prevented from entering productive elongation through factor-regulated termination.
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Affiliation(s)
- Nathan D Elrod
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Telmo Henriques
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Kai-Lieh Huang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Deirdre C Tatomer
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA.
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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44
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Tay MLI, Pek JW. SON protects nascent transcripts from unproductive degradation by counteracting DIP1. PLoS Genet 2019; 15:e1008498. [PMID: 31730657 PMCID: PMC6881055 DOI: 10.1371/journal.pgen.1008498] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/27/2019] [Accepted: 10/28/2019] [Indexed: 11/18/2022] Open
Abstract
Gene expression involves the transcription and splicing of nascent transcripts through the removal of introns. In Drosophila, a double-stranded RNA binding protein Disco-interacting protein 1 (DIP1) targets INE-1 stable intronic sequence RNAs (sisRNAs) for degradation after splicing. How nascent transcripts that also contain INE-1 sequences escape degradation remains unknown. Here we observe that these nascent transcripts can also be bound by DIP1 but the Drosophila homolog of SON (Dsn) protects them from unproductive degradation in ovaries. Dsn localizes to the satellite body where active decay of INE-1 sisRNAs by DIP1 occurs. Dsn is a repressor of DIP1 posttranslational modifications (primarily sumoylation) that are assumed to be required for efficient DIP1 activity. Moreover, the pre-mRNA destabilization caused by Dsn depletion is rescued in DIP1 or Sumo heterozygous mutants, suggesting that Dsn is a negative regulator of DIP1. Our results reveal that under normal circumstances nascent transcripts are susceptible to DIP1-mediated degradation, however intronic sequences are protected by Dsn until intron excision has taken place.
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Affiliation(s)
| | - Jun Wei Pek
- Temasek Life Sciences Laboratory, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
- * E-mail:
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45
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Telekawa C, Boisvert FM, Bachand F. Proteomic profiling and functional characterization of post-translational modifications of the fission yeast RNA exosome. Nucleic Acids Res 2019; 46:11169-11183. [PMID: 30321377 PMCID: PMC6265454 DOI: 10.1093/nar/gky915] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/11/2018] [Indexed: 12/11/2022] Open
Abstract
The RNA exosome is a conserved multi-subunit complex essential for processing and degradation of several types of RNAs. Although many of the functions of the RNA exosome are well established, whether the activity of this complex is regulated remains unclear. Here we performed a proteomic analysis of the RNA exosome complex purified from Schizosaccharomyces pombe and identified 39 post-translational modifications (PTMs), including phosphorylation, methylation, and acetylation sites. Interestingly, most of the modifications were identified in Dis3, a catalytic subunit of the RNA exosome, as well as in the exosome-associated RNA helicase, Mtr4. Functional analysis of selected PTM sites using modification-deficient and -mimetic versions of exosome subunits revealed substitutions that affected cell growth and exosome functions. Notably, our results suggest that site-specific phosphorylation in the catalytic center of Dis3 and in the helical bundle domain of Mtr4 control their activity. Our findings support a view in which post-translational modifications fine-tune exosome activity and add a layer of regulation to RNA degradation.
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Affiliation(s)
- Caroline Telekawa
- RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - François Bachand
- RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, QC, Canada
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46
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Peck SA, Hughes KD, Victorino JF, Mosley AL. Writing a wrong: Coupled RNA polymerase II transcription and RNA quality control. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1529. [PMID: 30848101 PMCID: PMC6570551 DOI: 10.1002/wrna.1529] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 12/20/2022]
Abstract
Processing and maturation of precursor RNA species is coupled to RNA polymerase II transcription. Co-transcriptional RNA processing helps to ensure efficient and proper capping, splicing, and 3' end processing of different RNA species to help ensure quality control of the transcriptome. Many improperly processed transcripts are not exported from the nucleus, are restricted to the site of transcription, and are in some cases degraded, which helps to limit any possibility of aberrant RNA causing harm to cellular health. These critical quality control pathways are regulated by the highly dynamic protein-protein interaction network at the site of transcription. Recent work has further revealed the extent to which the processes of transcription and RNA processing and quality control are integrated, and how critically their coupling relies upon the dynamic protein interactions that take place co-transcriptionally. This review focuses specifically on the intricate balance between 3' end processing and RNA decay during transcription termination. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Processing > 3' End Processing RNA Processing > Splicing Mechanisms RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Sarah A Peck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Katlyn D Hughes
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jose F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
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47
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Ruiz JC, Hunter OV, Conrad NK. Kaposi's sarcoma-associated herpesvirus ORF57 protein protects viral transcripts from specific nuclear RNA decay pathways by preventing hMTR4 recruitment. PLoS Pathog 2019; 15:e1007596. [PMID: 30785952 PMCID: PMC6398867 DOI: 10.1371/journal.ppat.1007596] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/04/2019] [Accepted: 01/25/2019] [Indexed: 12/15/2022] Open
Abstract
Nuclear RNAs are subject to a number of RNA decay pathways that serve quality control and regulatory functions. As a result, any virus that expresses its genes in the nucleus must have evolved mechanisms that avoid these pathways, but the how viruses evade nuclear RNA decay remains largely unknown. The multifunctional Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF57 (Mta) protein is required for the nuclear stability of viral transcripts. In the absence of ORF57, we show that viral transcripts are subject to degradation by two specific nuclear RNA decay pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) in which decay factors are recruited through poly(A) tails, and an ARS2-mediated RNA decay pathway dependent on the 5ʹ RNA cap. In transcription pulse chase assays, ORF57 appears to act primarily by inhibiting the ARS2-mediated RNA decay pathway. In the context of viral infection in cultured cells, inactivation of both decay pathways by RNAi is necessary for the restoration of ORF57-dependent viral genes produced from an ORF57-null bacmid. Mechanistically, we demonstrate that ORF57 protects viral transcripts by preventing the recruitment of the exosome co-factor hMTR4. In addition, our data suggest that ORF57 recruitment of ALYREF inhibits hMTR4 association with some viral RNAs, whereas other KSHV transcripts are stabilized by ORF57 in an ALYREF-independent fashion. In conclusion, our studies show that KSHV RNAs are subject to nuclear degradation by two specific host pathways, PPD and ARS2-mediated decay, and ORF57 protects viral transcripts from decay by inhibiting hMTR4 recruitment. Eukaryotic cells contain numerous nuclear RNA quality control (QC) systems that ensure transcriptome fidelity by detecting and degrading aberrant RNAs. Some viral RNAs are also predicted to be degraded by these RNA QC systems, so viruses have evolved mechanisms that counter host RNA QC pathways. Previous studies showed that the Kaposi’s sarcoma-associated herpesvirus (KSHV) expresses the ORF57 protein to protect its RNAs from nuclear decay. However, neither the specific host pathways that degrade KSHV RNAs nor the mechanisms describing ORF57 protection of viral RNAs were known. Our data suggest that ORF57 protects viral RNAs from two different nuclear RNA QC pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) and an ARS2-mediated RNA decay pathway. Mechanistically, we show that ORF57 binds directly to viral RNAs and prevents the recruitment of hMTR4, a cellular factor whose function is to recruit the exosome, the complex responsible for RNA decay, to the transcript. We conclude that by preventing hMTR4 recruitment, ORF57 protects viral RNAs from degradation resulting in robust expression of viral genes.
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Affiliation(s)
- Julio C. Ruiz
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Olga V. Hunter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Nicholas K. Conrad
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
- * E-mail:
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