1
|
Akirtava C, May G, McManus CJ. Deciphering the cis-regulatory landscape of natural yeast Transcript Leaders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.03.601937. [PMID: 39005336 PMCID: PMC11245039 DOI: 10.1101/2024.07.03.601937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Protein synthesis is a vital process that is highly regulated at the initiation step of translation. Eukaryotic 5' transcript leaders (TLs) contain a variety of cis-regulatory features that influence translation and mRNA stability. However, the relative influences of these features in natural TLs are poorly characterized. To address this, we used massively parallel reporter assays (MPRAs) to quantify RNA levels, ribosome loading, and protein levels from 11,027 natural yeast TLs in vivo and systematically compared the relative impacts of their sequence features on gene expression. We found that yeast TLs influence gene expression over two orders of magnitude. While a leaky scanning model using Kozak contexts and uAUGs explained half of the variance in expression across transcript leaders, the addition of other features explained ~70% of gene expression variation. Our analyses detected key cis-acting sequence features, quantified their effects in vivo, and compared their roles to motifs reported from an in vitro study of ribosome recruitment. In addition, our work quantitated the effects of alternative transcription start site usage on gene expression in yeast. Thus, our study provides new quantitative insights into the roles of TL cis-acting sequences in regulating gene expression.
Collapse
Affiliation(s)
- Christina Akirtava
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
- RNA Bioscience Initiative, University of Colorado - Anshutz, Aurora, CO, 80045, USA
| | - Gemma May
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - C Joel McManus
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| |
Collapse
|
2
|
Tseng YJ, Krans A, Malik I, Deng X, Yildirim E, Ovunc S, Tank EH, Jansen-West K, Kaufhold R, Gomez N, Sher R, Petrucelli L, Barmada S, Todd P. Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats. Nucleic Acids Res 2024; 52:5928-5949. [PMID: 38412259 PMCID: PMC11162809 DOI: 10.1093/nar/gkae137] [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: 06/07/2023] [Revised: 02/05/2024] [Accepted: 02/19/2024] [Indexed: 02/29/2024] Open
Abstract
A GGGGCC (G4C2) hexanucleotide repeat expansion in C9ORF72 causes amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD), while a CGG trinucleotide repeat expansion in FMR1 leads to the neurodegenerative disorder Fragile X-associated tremor/ataxia syndrome (FXTAS). These GC-rich repeats form RNA secondary structures that support repeat-associated non-AUG (RAN) translation of toxic proteins that contribute to disease pathogenesis. Here we assessed whether these same repeats might trigger stalling and interfere with translational elongation. We find that depletion of ribosome-associated quality control (RQC) factors NEMF, LTN1 and ANKZF1 markedly boost RAN translation product accumulation from both G4C2 and CGG repeats while overexpression of these factors reduces RAN production in both reporter assays and C9ALS/FTD patient iPSC-derived neurons. We also detected partially made products from both G4C2 and CGG repeats whose abundance increased with RQC factor depletion. Repeat RNA sequence, rather than amino acid content, is central to the impact of RQC factor depletion on RAN translation-suggesting a role for RNA secondary structure in these processes. Together, these findings suggest that ribosomal stalling and RQC pathway activation during RAN translation inhibits the generation of toxic RAN products. We propose augmenting RQC activity as a therapeutic strategy in GC-rich repeat expansion disorders.
Collapse
Affiliation(s)
- Yi-Ju Tseng
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48109, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502284 Telangana, India
| | - Xiexiong Deng
- Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Evrim Yildirim
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sinem Ovunc
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Elizabeth M H Tank
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Ross Kaufhold
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicolas B Gomez
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roger Sher
- Department of Neurobiology and Behavior & Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48109, USA
| |
Collapse
|
3
|
Mahé M, Rios-Fuller T, Katsara O, Schneider RJ. Non-canonical mRNA translation initiation in cell stress and cancer. NAR Cancer 2024; 6:zcae026. [PMID: 38828390 PMCID: PMC11140632 DOI: 10.1093/narcan/zcae026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 05/08/2024] [Accepted: 05/29/2024] [Indexed: 06/05/2024] Open
Abstract
The now well described canonical mRNA translation initiation mechanism of m7G 'cap' recognition by cap-binding protein eIF4E and assembly of the canonical pre-initiation complex consisting of scaffolding protein eIF4G and RNA helicase eIF4A has historically been thought to describe all cellular mRNA translation. However, the past decade has seen the discovery of alternative mechanisms to canonical eIF4E mediated mRNA translation initiation. Studies have shown that non-canonical alternate mechanisms of cellular mRNA translation initiation, whether cap-dependent or independent, serve to provide selective translation of mRNAs under cell physiological and pathological stress conditions. These conditions typically involve the global downregulation of canonical eIF4E1/cap-mediated mRNA translation, and selective translational reprogramming of the cell proteome, as occurs in tumor development and malignant progression. Cancer cells must be able to maintain physiological plasticity to acquire a migratory phenotype, invade tissues, metastasize, survive and adapt to severe microenvironmental stress conditions that involve inhibition of canonical mRNA translation initiation. In this review we describe the emerging, important role of non-canonical, alternate mechanisms of mRNA translation initiation in cancer, particularly in adaptation to stresses and the phenotypic cell fate changes involved in malignant progression and metastasis. These alternate translation initiation mechanisms provide new targets for oncology therapeutics development.
Collapse
Affiliation(s)
- Mélanie Mahé
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Tiffany Rios-Fuller
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Olga Katsara
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Robert J Schneider
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| |
Collapse
|
4
|
Ly J, Xiang K, Su KC, Sissoko GB, Bartel DP, Cheeseman IM. Nuclear release of eIF1 globally increases stringency of start-codon selection to preserve mitotic arrest physiology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.06.588385. [PMID: 38617206 PMCID: PMC11014515 DOI: 10.1101/2024.04.06.588385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Regulated start-codon selection has the potential to reshape the proteome through the differential production of uORFs, canonical proteins, and alternative translational isoforms. However, conditions under which start-codon selection is altered remain poorly defined. Here, using transcriptome-wide translation initiation site profiling, we reveal a global increase in the stringency of start-codon selection during mammalian mitosis. Low-efficiency initiation sites are preferentially repressed in mitosis, resulting in pervasive changes in the translation of thousands of start sites and their corresponding protein products. This increased stringency of start-codon selection during mitosis results from increased interactions between the key regulator of start-codon selection, eIF1, and the 40S ribosome. We find that increased eIF1-40S ribosome interactions during mitosis are mediated by the release of a nuclear pool of eIF1 upon nuclear envelope breakdown. Selectively depleting the nuclear pool of eIF1 eliminates the changes to translational stringency during mitosis, resulting in altered mitotic proteome composition. In addition, preventing mitotic translational rewiring results in substantially increased cell death and decreased mitotic slippage following treatment with anti-mitotic chemotherapeutics. Thus, cells globally control translation initiation stringency with critical roles during the mammalian cell cycle to preserve mitotic cell physiology.
Collapse
|
5
|
Bensaude O, Barbosa I, Morillo L, Dikstein R, Le Hir H. Exon-junction complex association with stalled ribosomes and slow translation-independent disassembly. Nat Commun 2024; 15:4209. [PMID: 38760352 PMCID: PMC11101648 DOI: 10.1038/s41467-024-48371-5] [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: 08/05/2023] [Accepted: 04/29/2024] [Indexed: 05/19/2024] Open
Abstract
Exon junction complexes are deposited at exon-exon junctions during splicing. They are primarily known to activate non-sense mediated degradation of transcripts harbouring premature stop codons before the last intron. According to a popular model, exon-junction complexes accompany mRNAs to the cytoplasm where the first translating ribosome pushes them out. However, they are also removed by uncharacterized, translation-independent mechanisms. Little is known about kinetic and transcript specificity of these processes. Here we tag core subunits of exon-junction complexes with complementary split nanoluciferase fragments to obtain sensitive and quantitative assays for complex formation. Unexpectedly, exon-junction complexes form large stable mRNPs containing stalled ribosomes. Complex assembly and disassembly rates are determined after an arrest in transcription and/or translation. 85% of newly deposited exon-junction complexes are disassembled by a translation-dependent mechanism. However as this process is much faster than the translation-independent one, only 30% of the exon-junction complexes present in cells at steady state require translation for disassembly. Deep RNA sequencing shows a bias of exon-junction complex bound transcripts towards microtubule and centrosome coding ones and demonstrate that the lifetimes of exon-junction complexes are transcript-specific. This study provides a dynamic vision of exon-junction complexes and uncovers their unexpected stable association with ribosomes.
Collapse
Affiliation(s)
- Olivier Bensaude
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
| | - Isabelle Barbosa
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Lucia Morillo
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
| |
Collapse
|
6
|
Meril S, Bahlsen M, Eisenstein M, Savidor A, Levin Y, Bialik S, Pietrokovski S, Kimchi A. Loss-of-function cancer-linked mutations in the EIF4G2 non-canonical translation initiation factor. Life Sci Alliance 2024; 7:e202302338. [PMID: 38129098 PMCID: PMC10746786 DOI: 10.26508/lsa.202302338] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
Tumor cells often exploit the protein translation machinery, resulting in enhanced protein expression essential for tumor growth. Since canonical translation initiation is often suppressed because of cell stress in the tumor microenvironment, non-canonical translation initiation mechanisms become particularly important for shaping the tumor proteome. EIF4G2 is a non-canonical translation initiation factor that mediates internal ribosome entry site (IRES)- and uORF-dependent initiation mechanisms, which can be used to modulate protein expression in cancer. Here, we explored the contribution of EIF4G2 to cancer by screening the COSMIC database for EIF4G2 somatic mutations in cancer patients. Functional examination of missense mutations revealed deleterious effects on EIF4G2 protein-protein interactions and, importantly, on its ability to mediate non-canonical translation initiation. Specifically, one mutation, R178Q, led to reductions in protein expression and near-complete loss of function. Two other mutations within the MIF4G domain specifically affected EIF4G2's ability to mediate IRES-dependent translation initiation but not that of target mRNAs with uORFs. These results shed light on both the structure-function of EIF4G2 and its potential tumor suppressor effects.
Collapse
Affiliation(s)
- Sara Meril
- https://ror.org/0316ej306 Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Marcela Bahlsen
- https://ror.org/0316ej306 Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Miriam Eisenstein
- https://ror.org/0316ej306 Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Alon Savidor
- https://ror.org/0316ej306 The de Botton Institute for Protein Profiling of the Nancy and Stephen Grand Israel National Center for Personalized Medicine (G-INCPM), Weizmann Institute of Science, Rehovot, Israel
| | - Yishai Levin
- https://ror.org/0316ej306 The de Botton Institute for Protein Profiling of the Nancy and Stephen Grand Israel National Center for Personalized Medicine (G-INCPM), Weizmann Institute of Science, Rehovot, Israel
| | - Shani Bialik
- https://ror.org/0316ej306 Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Shmuel Pietrokovski
- https://ror.org/0316ej306 Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Adi Kimchi
- https://ror.org/0316ej306 Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
7
|
Jia F, Zhang B, Yu W, Chen Z, Xu W, Zhao W, Wang Z. Exploring the cuproptosis-related molecular clusters in the peripheral blood of patients with amyotrophic lateral sclerosis. Comput Biol Med 2024; 168:107776. [PMID: 38056214 DOI: 10.1016/j.compbiomed.2023.107776] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 11/08/2023] [Accepted: 11/27/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a progressive and lethal neurodegenerative disease. Several studies have suggested the involvement of cuproptosis in its pathogenesis. In this research, we intend to explore the cuproptosis-related molecular clusters in ALS and develop a novel cuproptosis-related genes prediction model. METHODS The peripheral blood gene expression data was downloaded from the Gene Expression Omnibus (GEO) online database. Based on the GSE112681 dataset, we investigated the critical cuproptosis-related genes (CuRGs) and pathological clustering of ALS. The immune microenvironment features of the peripheral blood in ALS patients were also examined using the CIBERSORT algorithm. Cluster-specific hub genes were determined by the WGCNA. The most accurate prediction model was selected by comparing the performance of four machine learning techniques. ROC curves and two independent datasets were applied to validate the prediction accuracy. The available compounds targeting these hub genes were filtered to investigate their efficacy in treating ALS. RESULTS We successfully determined four critical cuproptosis-related genes and two pathological clusters with various immune profiles and biological characteristics in ALS. Functional analysis showed that genes in Cluster1 were primarily enriched in pathways closely associated with immunity. The Support Vector Machine (SVM) model exhibited the best discrimination properties with a large area under the curve (AUC = 0.862). Five hub prediction genes (BAP1, SMG1, BCLAF1, DHX15, EIF4G2) were selected to establish a nomogram model, suggesting significant risk prediction potential for ALS. The accuracy of this model in predicting ALS incidence was also demonstrated through calibration curves, nomograms, and decision curve analysis. Finally, three drugs targeting BAP1 were determined through drug-gene interactions. CONCLUSION This study elucidated the complex associations between cuproptosis and ALS and constructed a satisfactory predictive model to explore the pathological characteristics of different clusters in ALS patients.
Collapse
Affiliation(s)
- Fang Jia
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Bingchang Zhang
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Weijie Yu
- The School of Clinical Medicine, Fujian Medical University, Fuzhou, China
| | - Zheng Chen
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Wenbin Xu
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Wenpeng Zhao
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Zhanxiang Wang
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
| |
Collapse
|
8
|
Ito H, Machida K, Hasumi M, Ueyama M, Nagai Y, Imataka H, Taguchi H. Reconstitution of C9orf72 GGGGCC repeat-associated non-AUG translation with purified human translation factors. Sci Rep 2023; 13:22826. [PMID: 38129650 PMCID: PMC10739749 DOI: 10.1038/s41598-023-50188-z] [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: 08/28/2023] [Accepted: 12/16/2023] [Indexed: 12/23/2023] Open
Abstract
Nucleotide repeat expansion of GGGGCC (G4C2) in the non-coding region of C9orf72 is the most common genetic cause underlying amyotrophic lateral sclerosis and frontotemporal dementia. Transcripts harboring this repeat expansion undergo the translation of dipeptide repeats via a non-canonical process known as repeat-associated non-AUG (RAN) translation. In order to ascertain the essential components required for RAN translation, we successfully recapitulated G4C2-RAN translation using an in vitro reconstituted translation system comprising human factors, namely the human PURE system. Our findings conclusively demonstrate that the presence of fundamental translation factors is sufficient to mediate the elongation from the G4C2 repeat. Furthermore, the initiation mechanism proceeded in a 5' cap-dependent manner, independent of eIF2A or eIF2D. In contrast to cell lysate-mediated RAN translation, where longer G4C2 repeats enhanced translation, we discovered that the expansion of the G4C2 repeats inhibited translation elongation using the human PURE system. These results suggest that the repeat RNA itself functions as a repressor of RAN translation. Taken together, our utilization of a reconstituted RAN translation system employing minimal factors represents a distinctive and potent approach for elucidating the intricacies underlying RAN translation mechanism.
Collapse
Grants
- JPMJFS2112 Japan Science and Technology Agency
- JP26116002 Ministry of Education, Culture, Sports, Science and Technology
- JP18H03984 Ministry of Education, Culture, Sports, Science and Technology
- JP21H04763 Ministry of Education, Culture, Sports, Science and Technology
- JP20H05925 Ministry of Education, Culture, Sports, Science and Technology
- 2019-25 Mitsubishi Foundation
- 2019 Uehara Memorial Foundation
Collapse
Affiliation(s)
- Hayato Ito
- School of Life Science and Technology, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan
| | - Kodai Machida
- Graduate School of Engineering, University of Hyogo, Shosha, 2167, Himeji, Hyogo, 671-2280, Japan
| | - Mayuka Hasumi
- School of Life Science and Technology, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan
| | - Morio Ueyama
- Department of Neurology, Faculty of Medicine, Kindai University, Ohonohigashi 377-2, Osaka-Sayama, 589-8511, Japan
| | - Yoshitaka Nagai
- Department of Neurology, Faculty of Medicine, Kindai University, Ohonohigashi 377-2, Osaka-Sayama, 589-8511, Japan
| | - Hiroaki Imataka
- Graduate School of Engineering, University of Hyogo, Shosha, 2167, Himeji, Hyogo, 671-2280, Japan
| | - Hideki Taguchi
- School of Life Science and Technology, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan.
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan.
| |
Collapse
|
9
|
Grove DJ, Levine DJ, Kearse MG. Increased levels of eIF2A inhibit translation by sequestering 40S ribosomal subunits. Nucleic Acids Res 2023; 51:9983-10000. [PMID: 37602404 PMCID: PMC10570035 DOI: 10.1093/nar/gkad683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/22/2023] Open
Abstract
eIF2A was the first eukaryotic initiator tRNA carrier discovered but its exact function has remained enigmatic. Uncharacteristic of translation initiation factors, eIF2A is reported to be non-cytosolic in multiple human cancer cell lines. Attempts to study eIF2A mechanistically have been limited by the inability to achieve high yield of soluble recombinant protein. Here, we developed a purification paradigm that yields ∼360-fold and ∼6000-fold more recombinant human eIF2A from Escherichia coli and insect cells, respectively, than previous reports. Using a mammalian in vitro translation system, we found that increased levels of recombinant human eIF2A inhibit translation of multiple reporter mRNAs, including those that are translated by cognate and near-cognate start codons, and does so prior to start codon recognition. eIF2A also inhibited translation directed by all four types of cap-independent viral IRESs, including the CrPV IGR IRES that does not require initiation factors or initiator tRNA, suggesting excess eIF2A sequesters 40S subunits. Supplementation with additional 40S subunits prevented eIF2A-mediated inhibition and pull-down assays demonstrated direct binding between recombinant eIF2A and purified 40S subunits. These data support a model that eIF2A must be kept away from the translation machinery to avoid sequestering 40S ribosomal subunits.
Collapse
Affiliation(s)
- Daisy J Grove
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel J Levine
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Michael G Kearse
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
10
|
Fang JC, Liu MJ. Translation initiation at AUG and non-AUG triplets in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 335:111822. [PMID: 37574140 DOI: 10.1016/j.plantsci.2023.111822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 07/22/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023]
Abstract
In plants and other eukaryotes, precise selection of translation initiation site (TIS) on mRNAs shapes the proteome in response to cellular events or environmental cues. The canonical translation of mRNAs initiates at a 5' proximal AUG codon in a favorable context. However, the coding and non-coding regions of plant genomes contain numerous unannotated alternative AUG and non-AUG TISs. Determining how and why these unexpected and prevalent TISs are activated in plants has emerged as an exciting research area. In this review, we focus on the selection of plant TISs and highlight studies that revealed previously unannotated TISs used in vivo via comparative genomics and genome-wide profiling of ribosome positioning and protein N-terminal ends. The biological signatures of non-AUG TIS-initiated open reading frames (ORFs) in plants are also discussed. We describe what is understood about cis-regulatory RNA elements and trans-acting eukaryotic initiation factors (eIFs) in the site selection for translation initiation by featuring the findings in plants along with supporting findings in non-plant species. The prevalent, unannotated TISs provide a hidden reservoir of ORFs that likely help reshape plant proteomes in response to developmental or environmental cues. These findings underscore the importance of understanding the mechanistic basis of TIS selection to functionally annotate plant genomes, especially for crops with large genomes.
Collapse
Affiliation(s)
- Jhen-Cheng Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 711, Taiwan
| | - Ming-Jung Liu
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 711, Taiwan; Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan.
| |
Collapse
|
11
|
Huntzinger E, Sinteff J, Morlet B, Séraphin B. HELZ2: a new, interferon-regulated, human 3'-5' exoribonuclease of the RNB family is expressed from a non-canonical initiation codon. Nucleic Acids Res 2023; 51:9279-9293. [PMID: 37602378 PMCID: PMC10516660 DOI: 10.1093/nar/gkad673] [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: 03/21/2023] [Revised: 07/27/2023] [Accepted: 08/10/2023] [Indexed: 08/22/2023] Open
Abstract
Proteins containing a RNB domain, originally identified in Escherichia coli RNase II, are widely present throughout the tree of life. Many RNB proteins have 3'-5' exoribonucleolytic activity but some have lost catalytic activity during evolution. Database searches identified a new RNB domain-containing protein in human: HELZ2. Analysis of genomic and expression data combined with evolutionary information suggested that the human HELZ2 protein is produced from an unforeseen non-canonical initiation codon in Hominidae. This unusual property was confirmed experimentally, extending the human protein by 247 residues. Human HELZ2 was further shown to be an active ribonuclease despite the substitution of a key residue in its catalytic center. HELZ2 RNase activity is lost in cells from some cancer patients as a result of somatic mutations. HELZ2 harbors also two RNA helicase domains and several zinc fingers and its expression is induced by interferon treatment. We demonstrate that HELZ2 is able to degrade structured RNAs through the coordinated ATP-dependent displacement of duplex RNA mediated by its RNA helicase domains and its 3'-5' ribonucleolytic action. The expression characteristics and biochemical properties of HELZ2 support a role for this factor in response to viruses and/or mobile elements.
Collapse
Affiliation(s)
- Eric Huntzinger
- Institut de Génétique et de Biologie Moléculaire et cellulaire (IGBMC), Centre National de Recherche scientifique (CNRS) UMR 7104 - Institut National de santé et de Recherche Médicale (Inserm) U1258 - Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
| | - Jordan Sinteff
- Institut de Génétique et de Biologie Moléculaire et cellulaire (IGBMC), Centre National de Recherche scientifique (CNRS) UMR 7104 - Institut National de santé et de Recherche Médicale (Inserm) U1258 - Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
| | - Bastien Morlet
- Institut de Génétique et de Biologie Moléculaire et cellulaire (IGBMC), Centre National de Recherche scientifique (CNRS) UMR 7104 - Institut National de santé et de Recherche Médicale (Inserm) U1258 - Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
| | - Bertrand Séraphin
- Institut de Génétique et de Biologie Moléculaire et cellulaire (IGBMC), Centre National de Recherche scientifique (CNRS) UMR 7104 - Institut National de santé et de Recherche Médicale (Inserm) U1258 - Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
| |
Collapse
|
12
|
Malik I, Tseng YJ, Wieland CM, Green KM, Zheng K, Calleja K, Todd PK. Dissecting the roles of EIF4G homologs reveals DAP5 as a modifier of CGG repeat-associated toxicity in a Drosophila model of FXTAS. Neurobiol Dis 2023; 184:106212. [PMID: 37352983 PMCID: PMC11149892 DOI: 10.1016/j.nbd.2023.106212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 06/25/2023] Open
Abstract
Neurodegeneration in Fragile X-associated tremor/ataxia syndrome (FXTAS) is caused by a CGG trinucleotide repeat expansion in the 5' UTR of FMR1. Expanded CGG repeat RNAs form stable secondary structures, which in turn support repeat-associated non-AUG (RAN) translation to produce toxic peptides. The parameters that impact RAN translation initiation efficiency are not well understood. Here we used a Drosophila melanogaster model of FXTAS to evaluate the role of the eIF4G family of eukaryotic translation initiation factors (EIF4G1, EIF4GII and EIF4G2/DAP5) in modulating RAN translation and CGG repeat-associated toxicity. DAP5 knockdown robustly suppressed CGG repeat-associated toxicity and inhibited RAN translation. Furthermore, knockdown of initiation factors that preferentially associate with DAP5 (such as EIF2β, EIF3F and EIF3G) also selectively suppressed CGG repeat-induced eye degeneration. In mammalian cellular reporter assays, DAP5 knockdown exhibited modest and cell-type specific effects on RAN translation. Taken together, these data support a role for DAP5 in CGG repeat associated toxicity possibly through modulation of RAN translation.
Collapse
Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Yi-Ju Tseng
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Clare M Wieland
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Kristina Zheng
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Katyanne Calleja
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA.
| |
Collapse
|
13
|
Yin K, Tong M, Suttapitugsakul S, Xu S, Wu R. Global quantification of newly synthesized proteins reveals cell type- and inhibitor-specific effects on protein synthesis inhibition. PNAS NEXUS 2023; 2:pgad168. [PMID: 37275259 PMCID: PMC10235912 DOI: 10.1093/pnasnexus/pgad168] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/05/2023] [Accepted: 05/15/2023] [Indexed: 06/07/2023]
Abstract
Manipulation of protein synthesis is commonly applied to uncover protein functions and cellular activities. Multiple inhibitors with distinct mechanisms have been widely investigated and employed in bio-related research, but it is extraordinarily challenging to measure and evaluate the synthesis inhibition efficiencies of individual proteins by different inhibitors at the proteome level. Newly synthesized proteins are the immediate and direct products of protein synthesis, and thus their comprehensive quantification provides a unique opportunity to study protein inhibition. Here, we systematically investigate protein inhibition and evaluate different popular inhibitors, i.e. cycloheximide, puromycin, and anisomycin, through global quantification of newly synthesized proteins in several types of human cells (A549, MCF-7, Jurkat, and THP-1 cells). The inhibition efficiencies of protein synthesis are comprehensively measured by integrating azidohomoalanine-based protein labeling, selective enrichment, a boosting approach, and multiplexed proteomics. The same inhibitor results in dramatic variation of the synthesis inhibition efficiencies for different proteins in the same cells, and each inhibitor exhibits unique preferences. Besides cell type- and inhibitor-specific effects, some universal rules are unraveled. For instance, nucleolar and ribosomal proteins have relatively higher inhibition efficiencies in every type of cells treated with each inhibitor. Moreover, proteins intrinsically resistant or sensitive to the inhibition are identified and found to have distinct functions. Systematic investigation of protein synthesis inhibition in several types of human cells by different inhibitors provides valuable information about the inhibition of protein synthesis, advancing our understanding of inhibiting protein synthesis.
Collapse
Affiliation(s)
| | | | - Suttipong Suttapitugsakul
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Senhan Xu
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Ronghu Wu
- To whom correspondence should be addressed:
| |
Collapse
|
14
|
May GE, Akirtava C, Agar-Johnson M, Micic J, Woolford J, McManus J. Unraveling the influences of sequence and position on yeast uORF activity using massively parallel reporter systems and machine learning. eLife 2023; 12:e69611. [PMID: 37227054 PMCID: PMC10259493 DOI: 10.7554/elife.69611] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/24/2023] [Indexed: 05/26/2023] Open
Abstract
Upstream open-reading frames (uORFs) are potent cis-acting regulators of mRNA translation and nonsense-mediated decay (NMD). While both AUG- and non-AUG initiated uORFs are ubiquitous in ribosome profiling studies, few uORFs have been experimentally tested. Consequently, the relative influences of sequence, structural, and positional features on uORF activity have not been determined. We quantified thousands of yeast uORFs using massively parallel reporter assays in wildtype and ∆upf1 yeast. While nearly all AUG uORFs were robust repressors, most non-AUG uORFs had relatively weak impacts on expression. Machine learning regression modeling revealed that both uORF sequences and locations within transcript leaders predict their effect on gene expression. Indeed, alternative transcription start sites highly influenced uORF activity. These results define the scope of natural uORF activity, identify features associated with translational repression and NMD, and suggest that the locations of uORFs in transcript leaders are nearly as predictive as uORF sequences.
Collapse
Affiliation(s)
- Gemma E May
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Christina Akirtava
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Matthew Agar-Johnson
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Jelena Micic
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - John Woolford
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Joel McManus
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
- Computational Biology Department, Carnegie Mellon UniversityPittsburghUnited States
| |
Collapse
|
15
|
Bukhari SIA, Truesdell SS, Datta C, Choudhury P, Wu KQ, Shrestha J, Maharjan R, Plotsker E, Elased R, Laisa S, Bhambhani V, Lin Y, Kreuzer J, Morris R, Koh SB, Ellisen LW, Haas W, Ly A, Vasudevan S. Regulation of RNA methylation by therapy treatment, promotes tumor survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.540602. [PMID: 37292633 PMCID: PMC10245743 DOI: 10.1101/2023.05.19.540602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Our data previously revealed that chemosurviving cancer cells translate specific genes. Here, we find that the m6A-RNA-methyltransferase, METTL3, increases transiently in chemotherapy-treated breast cancer and leukemic cells in vitro and in vivo. Consistently, m6A increases on RNA from chemo-treated cells, and is needed for chemosurvival. This is regulated by eIF2α phosphorylation and mTOR inhibition upon therapy treatment. METTL3 mRNA purification reveals that eIF3 promotes METTL3 translation that is reduced by mutating a 5'UTR m6A-motif or depleting METTL3. METTL3 increase is transient after therapy treatment, as metabolic enzymes that control methylation and thus m6A levels on METTL3 RNA, are altered over time after therapy. Increased METTL3 reduces proliferation and anti-viral immune response genes, and enhances invasion genes, which promote tumor survival. Consistently, overriding phospho-eIF2α prevents METTL3 elevation, and reduces chemosurvival and immune-cell migration. These data reveal that therapy-induced stress signals transiently upregulate METTL3 translation, to alter gene expression for tumor survival.
Collapse
Affiliation(s)
- Syed IA Bukhari
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Samuel S Truesdell
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Chandreyee Datta
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Pritha Choudhury
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Keith Q Wu
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Jitendra Shrestha
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Ruby Maharjan
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Ethan Plotsker
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Ramzi Elased
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Sadia Laisa
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Vijeta Bhambhani
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Yue Lin
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Johannes Kreuzer
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Robert Morris
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Siang-Boon Koh
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Leif W. Ellisen
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Wilhelm Haas
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Amy Ly
- Department of Pathology, Massachusetts General Hospital, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Shobha Vasudevan
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| |
Collapse
|
16
|
Shestakova ED, Smirnova VV, Shatsky IN, Terenin IM. Specific mechanisms of translation initiation in higher eukaryotes: the eIF4G2 story. RNA (NEW YORK, N.Y.) 2023; 29:282-299. [PMID: 36517212 PMCID: PMC9945437 DOI: 10.1261/rna.079462.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The eukaryotic initiation factor 4G2 (eIF4G2, DAP5, Nat1, p97) was discovered in 1997. Over the past two decades, dozens of papers have presented contradictory data on eIF4G2 function. Since its identification, eIF4G2 has been assumed to participate in noncanonical translation initiation mechanisms, but recent results indicate that it can be involved in scanning as well. In particular, eIF4G2 provides leaky scanning through some upstream open reading frames (uORFs), which are typical for long 5' UTRs of mRNAs from higher eukaryotes. It is likely the protein can also help the ribosome overcome other impediments during scanning of the 5' UTRs of animal mRNAs. This may explain the need for eIF4G2 in higher eukaryotes, as many mRNAs that encode regulatory proteins have rather long and highly structured 5' UTRs. Additionally, they often bind to various proteins, which also hamper the movement of scanning ribosomes. This review discusses the suggested mechanisms of eIF4G2 action, denotes obscure or inconsistent results, and proposes ways to uncover other fundamental mechanisms in which this important protein factor may be involved in higher eukaryotes.
Collapse
Affiliation(s)
- Ekaterina D Shestakova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Victoria V Smirnova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
- Sirius University of Science and Technology, Sochi 354349, Russia
| |
Collapse
|
17
|
Reyes CJ, Asano K, Todd PK, Klein C, Rakovic A. Repeat-Associated Non-AUG Translation of AGAGGG Repeats that Cause X-Linked Dystonia-Parkinsonism. Mov Disord 2022; 37:2284-2289. [PMID: 35971992 DOI: 10.1002/mds.29183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 07/05/2022] [Accepted: 07/21/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND X-linked dystonia-parkinsonism (XDP) is a neurodegenerative disorder caused by the intronic insertion of a SINE-VNTR-Alu (SVA) retrotransposon carrying an (AGAGGG)n repeat expansion in the TAF1 gene. The molecular mechanisms by which this mutation causes neurodegeneration remain elusive. OBJECTIVES We investigated whether (AGAGGG)n repeats undergo repeat-associated non-AUG (RAN) translation, a pathogenic mechanism common among repeat expansion diseases. METHODS XDP-specific RAN translation reporter plasmids were generated, transfected in HEK293 cells, and putative dipeptide repeat proteins (DPRs) were detected by Western blotting. Immunocytochemistry was performed in COS-7 cells to determine the subcellular localization of one DPR. RESULTS We detected putative DPRs from two reading frames, supporting the translation of poly-(Glu-Gly) and poly-(Arg-Glu) species. XDP RAN translation initiates within the (AGAGGG)n sequence and poly-(Glu-Gly) DPRs formed nuclear inclusions in transfected cells. CONCLUSIONS In summary, our work provides the first in-vitro proof of principle that the XDP-linked (AGAGGG)n repeat expansions can undergo RAN translation. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
- Laboratory of Translational Control Study, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Hiroshima Research Center for Healthy Aging, Hiroshima University, Hiroshima, Japan
| | - Peter K Todd
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Veterans Affairs Medical Center, Ann Arbor, Michigan, USA
| | | | | |
Collapse
|
18
|
Datta C, Truesdell SS, Wu KQ, Bukhari SIA, Ngue H, Buchanan B, Le Tonqueze O, Lee S, Kollu S, Granovetter MA, Boukhali M, Kreuzer J, Batool MS, Balaj L, Haas W, Vasudevan S. Ribosome changes reprogram translation for chemosurvival in G0 leukemic cells. SCIENCE ADVANCES 2022; 8:eabo1304. [PMID: 36306353 PMCID: PMC9616492 DOI: 10.1126/sciadv.abo1304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Quiescent leukemic cells survive chemotherapy, with translation changes. Our data reveal that FXR1, a protein amplified in several aggressive cancers, is elevated in quiescent and chemo-treated leukemic cells and promotes chemosurvival. This suggests undiscovered roles for this RNA- and ribosome-associated protein in chemosurvival. We find that FXR1 depletion reduces translation, with altered rRNAs, snoRNAs, and ribosomal proteins (RPs). FXR1 regulates factors that promote transcription and processing of ribosomal genes and snoRNAs. Ribosome changes in FXR1-overexpressing cells, including RPLP0/uL10 levels, activate eIF2α kinases. Accordingly, phospho-eIF2α increases, enabling selective translation of survival and immune regulators in FXR1-overexpressing cells. Overriding these genes or phospho-eIF2α with inhibitors reduces chemosurvival. Thus, elevated FXR1 in quiescent or chemo-treated leukemic cells alters ribosomes that trigger stress signals to redirect translation for chemosurvival.
Collapse
Affiliation(s)
- Chandreyee Datta
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Samuel S. Truesdell
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Keith Q. Wu
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Syed I. A. Bukhari
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Harrison Ngue
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Brienna Buchanan
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Olivier Le Tonqueze
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Sooncheol Lee
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Swapna Kollu
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Madeleine A. Granovetter
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Myriam Boukhali
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Johannes Kreuzer
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Maheen S. Batool
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Leonora Balaj
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Wilhelm Haas
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Shobha Vasudevan
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
- Corresponding author.
| |
Collapse
|
19
|
Bottorff TA, Park H, Geballe AP, Subramaniam AR. Translational buffering by ribosome stalling in upstream open reading frames. PLoS Genet 2022; 18:e1010460. [PMID: 36315596 PMCID: PMC9648851 DOI: 10.1371/journal.pgen.1010460] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/10/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022] Open
Abstract
Upstream open reading frames (uORFs) are present in over half of all human mRNAs. uORFs can potently regulate the translation of downstream open reading frames through several mechanisms: siphoning away scanning ribosomes, regulating re-initiation, and allowing interactions between scanning and elongating ribosomes. However, the consequences of these different mechanisms for the regulation of protein expression remain incompletely understood. Here, we performed systematic measurements on the uORF-containing 5' UTR of the cytomegaloviral UL4 mRNA to test alternative models of uORF-mediated regulation in human cells. We find that a terminal diproline-dependent elongating ribosome stall in the UL4 uORF prevents decreases in main ORF protein expression when ribosome loading onto the mRNA is reduced. This uORF-mediated buffering is insensitive to the location of the ribosome stall along the uORF. Computational kinetic modeling based on our measurements suggests that scanning ribosomes dissociate rather than queue when they collide with stalled elongating ribosomes within the UL4 uORF. We identify several human uORFs that repress main ORF protein expression via a similar terminal diproline motif. We propose that ribosome stalls in uORFs provide a general mechanism for buffering against reductions in main ORF translation during stress and developmental transitions.
Collapse
Affiliation(s)
- Ty A. Bottorff
- Basic Sciences Division and Computational Biology Program of the Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Biological Physics, Structure and Design Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Heungwon Park
- Basic Sciences Division and Computational Biology Program of the Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Adam P. Geballe
- Human Biology and Clinical Research Divisions, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Arvind Rasi Subramaniam
- Basic Sciences Division and Computational Biology Program of the Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Biological Physics, Structure and Design Graduate Program, University of Washington, Seattle, Washington, United States of America
| |
Collapse
|
20
|
Green KM, Miller SL, Malik I, Todd PK. Non-canonical initiation factors modulate repeat-associated non-AUG translation. Hum Mol Genet 2022; 31:2521-2534. [PMID: 35220421 PMCID: PMC9618161 DOI: 10.1093/hmg/ddac021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/28/2021] [Accepted: 01/14/2022] [Indexed: 11/14/2022] Open
Abstract
Repeat-associated non-AUG (RAN) translation of expanded repeat-mutation mRNA produces toxic peptides in neurons of patients suffering from neurodegenerative diseases. Recent findings indicate that RAN translation in diverse model systems is not inhibited by cellular stressors that impair global translation through phosphorylation of the alpha subunit of eIF2, the essential eukaryotic translation initiation factor that brings the initiator tRNA to the 40S ribosome. Using in vitro, cell-based and Drosophila models, we examined the role of alternative ternary complex factors that may function in place of eIF2, including eIF2A, eIF2D, DENR and MCTS1. Among these factors, DENR knockdown had the greatest inhibitory effect on RAN translation of expanded GGGGCC and CGG repeat reporters and its reduction improved the survival of Drosophila expressing expanded GGGGCC repeats. Taken together, these data support a role for alternative initiation factors in RAN translation and suggest these may serve as novel therapeutic targets in neurodegenerative disease.
Collapse
Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Shannon L Miller
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| |
Collapse
|
21
|
Compounds for selective translational inhibition. Curr Opin Chem Biol 2022; 69:102158. [DOI: 10.1016/j.cbpa.2022.102158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/04/2022] [Accepted: 04/17/2022] [Indexed: 11/23/2022]
|
22
|
Liu Y, Zeng S, Wu M. Novel insights into noncanonical open reading frames in cancer. Biochim Biophys Acta Rev Cancer 2022; 1877:188755. [PMID: 35777601 DOI: 10.1016/j.bbcan.2022.188755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/11/2022] [Accepted: 06/23/2022] [Indexed: 12/12/2022]
Abstract
With technological advances, previously neglected noncanonical open reading frames (nORFs) are drawing ever-increasing attention. However, the translation potential of numerous putative nORFs remains elusive, and the functions of noncanonical peptides have not been systemically summarized. Moreover, the relationship between noncanonical peptides and their counterpart protein or RNA products remains elusive and the clinical implementation of noncanonical peptides has not been explored. In this review, we highlight how recent technological advances such as ribosome profiling, bioinformatics approaches and CRISPR/Cas9 facilitate the research of noncanonical peptides. We delineate the features of each nORF category and the evolutionary process underneath the nORFs. Most importantly, we summarize the diversified functions of noncanonical peptides in cancer based on their subcellular location, which reflect their extensive participation in key pathways and essential cellular activities in cancer cells. Meanwhile, the equilibrium between noncanonical peptides and their corresponding transcripts or counterpart products may be dysregulated under pathological states, which is essential for their roles in cancer. Lastly, we explore their underestimated potential in clinical application as diagnostic biomarkers and treatment targets against cancer.
Collapse
Affiliation(s)
- Yihan Liu
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, Hunan, China; The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China; Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory for Molecular Radiation Oncology of Hunan Province, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Shan Zeng
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory for Molecular Radiation Oncology of Hunan Province, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
| | - Minghua Wu
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, Hunan, China; The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China.
| |
Collapse
|
23
|
Ai Y, Liang D, Wilusz JE. CRISPR/Cas13 effectors have differing extents of off-target effects that limit their utility in eukaryotic cells. Nucleic Acids Res 2022; 50:e65. [PMID: 35244715 PMCID: PMC9226543 DOI: 10.1093/nar/gkac159] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/01/2022] [Accepted: 02/21/2022] [Indexed: 12/26/2022] Open
Abstract
CRISPR/Cas13 effectors have garnered increasing attention as easily customizable tools for detecting and depleting RNAs of interest. Near perfect complementarity between a target RNA and the Cas13-associated guide RNA is required for activation of Cas13 ribonuclease activity. Nonetheless, the specificity of Cas13 effectors in eukaryotic cells has been debated as the Cas13 nuclease domains can be exposed on the enzyme surface, providing the potential for promiscuous cleavage of nearby RNAs (so-called collateral damage). Here, using co-transfection assays in Drosophila and human cells, we found that the off-target effects of RxCas13d, a commonly used Cas13 effector, can be as strong as the level of on-target RNA knockdown. The extent of off-target effects is positively correlated with target RNA expression levels, and collateral damage can be observed even after reducing RxCas13d/guide RNA levels. The PspCas13b effector showed improved specificity and, unlike RxCas13d, can be used to deplete a Drosophila circular RNA without affecting the expression of the associated linear RNA. PspCas13b nonetheless still can have off-target effects and we notably found that the extent of off-target effects for Cas13 effectors differs depending on the cell type and target RNA examined. In total, these results highlight the need for caution when designing and interpreting Cas13-based knockdown experiments.
Collapse
Affiliation(s)
- Yuxi Ai
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Dongming Liang
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
24
|
Fritz SE, Ranganathan S, Wang CD, Hogg JR. An alternative UPF1 isoform drives conditional remodeling of nonsense-mediated mRNA decay. EMBO J 2022; 41:e108898. [PMID: 35403729 PMCID: PMC9108617 DOI: 10.15252/embj.2021108898] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 03/18/2022] [Accepted: 03/25/2022] [Indexed: 12/11/2022] Open
Abstract
The nonsense-mediated mRNA decay (NMD) pathway monitors translation termination in order to degrade transcripts with premature stop codons and regulate thousands of human genes. Here, we show that an alternative mammalian-specific isoform of the core NMD factor UPF1, termed UPF1LL , enables condition-dependent remodeling of NMD specificity. Previous studies indicate that the extension of a conserved regulatory loop in the UPF1LL helicase core confers a decreased propensity to dissociate from RNA upon ATP hydrolysis relative to UPF1SL , the major UPF1 isoform. Using biochemical and transcriptome-wide approaches, we find that UPF1LL can circumvent the protective RNA binding proteins PTBP1 and hnRNP L to preferentially bind and down-regulate transcripts with long 3'UTRs normally shielded from NMD. Unexpectedly, UPF1LL supports induction of NMD on new populations of substrate mRNAs in response to activation of the integrated stress response and impaired translation efficiency. Thus, while canonical NMD is abolished by moderate translational repression, UPF1LL activity is enhanced, offering the possibility to rapidly rewire NMD specificity in response to cellular stress.
Collapse
Affiliation(s)
- Sarah E Fritz
- Biochemistry and Biophysics CenterNational Heart, Lung, and Blood InstituteNational Institutes of HealthBethesdaMDUSA
| | - Soumya Ranganathan
- Biochemistry and Biophysics CenterNational Heart, Lung, and Blood InstituteNational Institutes of HealthBethesdaMDUSA
| | - Clara D Wang
- Biochemistry and Biophysics CenterNational Heart, Lung, and Blood InstituteNational Institutes of HealthBethesdaMDUSA
| | - J Robert Hogg
- Biochemistry and Biophysics CenterNational Heart, Lung, and Blood InstituteNational Institutes of HealthBethesdaMDUSA
| |
Collapse
|
25
|
Andreev DE, Loughran G, Fedorova AD, Mikhaylova MS, Shatsky IN, Baranov PV. Non-AUG translation initiation in mammals. Genome Biol 2022; 23:111. [PMID: 35534899 PMCID: PMC9082881 DOI: 10.1186/s13059-022-02674-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 04/14/2022] [Indexed: 12/12/2022] Open
Abstract
Recent proteogenomic studies revealed extensive translation outside of annotated protein coding regions, such as non-coding RNAs and untranslated regions of mRNAs. This non-canonical translation is largely due to start codon plurality within the same RNA. This plurality is often due to the failure of some scanning ribosomes to recognize potential start codons leading to initiation downstream—a process termed leaky scanning. Codons other than AUG (non-AUG) are particularly leaky due to their inefficiency. Here we discuss our current understanding of non-AUG initiation. We argue for a near-ubiquitous role of non-AUG initiation in shaping the dynamic composition of mammalian proteomes.
Collapse
|
26
|
Soukarieh O, Meguerditchian C, Proust C, Aïssi D, Eyries M, Goyenvalle A, Trégouët DA. Common and Rare 5′UTR Variants Altering Upstream Open Reading Frames in Cardiovascular Genomics. Front Cardiovasc Med 2022; 9:841032. [PMID: 35387445 PMCID: PMC8977850 DOI: 10.3389/fcvm.2022.841032] [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: 12/21/2021] [Accepted: 02/21/2022] [Indexed: 01/16/2023] Open
Abstract
High-throughput sequencing (HTS) technologies are revolutionizing the research and molecular diagnosis landscape by allowing the exploration of millions of nucleotide sequences at an unprecedented scale. These technologies are of particular interest in the identification of genetic variations contributing to the risk of rare (Mendelian) and common (multifactorial) human diseases. So far, they have led to numerous successes in identifying rare disease-causing mutations in coding regions, but few in non-coding regions that include introns, untranslated (UTR), and intergenic regions. One class of neglected non-coding variations is that of 5′UTR variants that alter upstream open reading frames (upORFs) of the coding sequence (CDS) of a natural protein coding transcript. Following a brief summary of the molecular bases of the origin and functions of upORFs, we will first review known 5′UTR variations altering upORFs and causing rare cardiovascular disorders (CVDs). We will then investigate whether upORF-affecting single nucleotide polymorphisms could be good candidates for explaining association signals detected in the context of genome-wide association studies for common complex CVDs.
Collapse
Affiliation(s)
- Omar Soukarieh
- INSERM, Bordeaux Population Health, U1219, Molecular Epidemiology of Vascular and Brain Disorders, University of Bordeaux, Bordeaux, France
- *Correspondence: Omar Soukarieh,
| | - Caroline Meguerditchian
- INSERM, Bordeaux Population Health, U1219, Molecular Epidemiology of Vascular and Brain Disorders, University of Bordeaux, Bordeaux, France
| | - Carole Proust
- INSERM, Bordeaux Population Health, U1219, Molecular Epidemiology of Vascular and Brain Disorders, University of Bordeaux, Bordeaux, France
| | - Dylan Aïssi
- INSERM, Bordeaux Population Health, U1219, Molecular Epidemiology of Vascular and Brain Disorders, University of Bordeaux, Bordeaux, France
| | - Mélanie Eyries
- Department of Genetics, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Paris, France
| | | | - David-Alexandre Trégouët
- INSERM, Bordeaux Population Health, U1219, Molecular Epidemiology of Vascular and Brain Disorders, University of Bordeaux, Bordeaux, France
| |
Collapse
|
27
|
Jiaze Y, Sinan H, Minjie Y, Yongjie Z, Nan D, Liangwen W, Wen Z, Jianjun L, Zhiping Y. Rcl1 suppresses tumor progression of hepatocellular carcinoma: a comprehensive analysis of bioinformatics and in vitro experiments. Cancer Cell Int 2022; 22:114. [PMID: 35264160 PMCID: PMC8905783 DOI: 10.1186/s12935-022-02533-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/24/2022] [Indexed: 11/10/2022] Open
Abstract
Background RNA 3’-terminal phosphate cyclase-like protein (Rcl1) is involved in pre-rRNA processing, but its implication in cancers remains unclear. Methods RCL1 expressions in 21 malignancies was examinated through GEPIA website portal. Clinical implication data related to RCL1 level in Hepatocellular Carcinoma (HCC) samples were downloaded through TCGA, ICGC, GEO databases. Survival analysis and gene function enrichment analyses were performed through R software. The correlation between RCL1 expression and tumor immune infiltration was assessed via the TIMER2.0 database. The effects of Rcl1 overexpression or knockdown on cell growth and metastasis was evaluated by CCK8, transwell, and cell cycle assays. Results RCL1 expression is commonly down-regulated in HCC. The lower expression of RCL1 is associated with higher tumor stage, higher AFP level, vascular invasion, and poor prognosis. RCL1 expression has a significant correlation with immune cells infiltration in HCC, especially myeloid-derived suppressor cell (MDSC). Moreover, it was further identified that Rcl1 expression was reduced in HCC cell lines and negatively correlated with invasion of HCC cell lines. Immunofluorescence (IF) analysis revealed that the level of Rcl1 expression in the cytoplasm of HCC cells is significantly lower than that in the cytoplasm of L-02 cell. Moreover, both gain- and loss-of-function studies demonstrated that Rcl1 inhibited the growth and metastasis of HCC cells and regulated cell cycle progression in vitro. Conclusions Rcl1 may serve as a novel tumor suppressor in HCC, and its biological effect needs further study. Supplementary Information The online version contains supplementary material available at 10.1186/s12935-022-02533-x. Rcl1 mRNA expression is down-regulated within HCC tissues and associated with poor prognosis and disease progression. Anti-cancer effects of Rcl1 on HCC were confirmed in vitro. Rcl1 may be a potential tumor suppressor in HCC.
Collapse
Affiliation(s)
- Yu Jiaze
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China.,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China
| | - Hou Sinan
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China.,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China
| | - Yang Minjie
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China.,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China
| | - Zhou Yongjie
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China.,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China
| | - Du Nan
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China.,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China
| | - Wang Liangwen
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China.,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China
| | - Zhang Wen
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China. .,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China. .,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China.
| | - Luo Jianjun
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China. .,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China. .,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China.
| | - Yan Zhiping
- Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China. .,National Clinical Research Center for Interventional Medicine, 180 Fenglin Road, Shanghai, 200032, China. .,Shanghai Institution of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China.
| |
Collapse
|
28
|
Zhang Y, Glineburg MR, Basrur V, Conlon K, Wright SE, Krans A, Hall DA, Todd PK. Mechanistic convergence across initiation sites for RAN translation in fragile X associated tremor ataxia syndrome. Hum Mol Genet 2022; 31:2317-2332. [PMID: 35137065 PMCID: PMC9307318 DOI: 10.1093/hmg/ddab353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Repeat associated non-AUG (RAN) translation of CGG repeats in the 5'UTR of FMR1 produces toxic proteins that contribute to fragile X-associated tremor/ataxia syndrome (FXTAS) pathogenesis. The most abundant RAN product, FMRpolyG, initiates predominantly at an ACG upstream of the repeat. Accurate FMRpolyG measurements in FXTAS patients are lacking. We used data-dependent acquisition and parallel reaction monitoring (PRM) mass spectrometry coupled with stable isotope labeled standard peptides to identify signature FMRpolyG fragments in patient samples. Following immunoprecipitation, PRM detected FMRpolyG signature peptides in transfected cells, and FXTAS tissues and cells, but not in controls. We identified two amino-terminal peptides: an ACG-initiated Ac-MEAPLPGGVR and a GUG-initiated Ac-TEAPLPGGVR, as well as evidence for RAN translation initiation within the CGG repeat itself in two reading frames. Initiation at all sites increased following cellular stress, decreased following eIF1 overexpression and was eIF4A and M7G cap-dependent. These data demonstrate that FMRpolyG is quantifiable in human samples and FMR1 RAN translation initiates via similar mechanisms for near-cognate codons and within the repeat through processes dependent on available initiation factors and cellular environment.
Collapse
Affiliation(s)
- Yuan Zhang
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA,Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha 410008, China
| | - M Rebecca Glineburg
- To whom correspondence should be addressed at: Todd Lab (ATTN: Drs Glineburg and Todd), 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA. Tel: +1 7346155632; Fax: +1 7346479777; ;
| | | | - Kevin Conlon
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Deborah A Hall
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Peter K Todd
- To whom correspondence should be addressed at: Todd Lab (ATTN: Drs Glineburg and Todd), 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA. Tel: +1 7346155632; Fax: +1 7346479777; ;
| |
Collapse
|
29
|
Kute PM, Soukarieh O, Tjeldnes H, Trégouët DA, Valen E. Small Open Reading Frames, How to Find Them and Determine Their Function. Front Genet 2022; 12:796060. [PMID: 35154250 PMCID: PMC8831751 DOI: 10.3389/fgene.2021.796060] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/30/2021] [Indexed: 12/12/2022] Open
Abstract
Advances in genomics and molecular biology have revealed an abundance of small open reading frames (sORFs) across all types of transcripts. While these sORFs are often assumed to be non-functional, many have been implicated in physiological functions and a significant number of sORFs have been described in human diseases. Thus, sORFs may represent a hidden repository of functional elements that could serve as therapeutic targets. Unlike protein-coding genes, it is not necessarily the encoded peptide of an sORF that enacts its function, sometimes simply the act of translating an sORF might have a regulatory role. Indeed, the most studied sORFs are located in the 5′UTRs of coding transcripts and can have a regulatory impact on the translation of the downstream protein-coding sequence. However, sORFs have also been abundantly identified in non-coding RNAs including lncRNAs, circular RNAs and ribosomal RNAs suggesting that sORFs may be diverse in function. Of the many different experimental methods used to discover sORFs, the most commonly used are ribosome profiling and mass spectrometry. These can confirm interactions between transcripts and ribosomes and the production of a peptide, respectively. Extensions to ribosome profiling, which also capture scanning ribosomes, have further made it possible to see how sORFs impact the translation initiation of mRNAs. While high-throughput techniques have made the identification of sORFs less difficult, defining their function, if any, is typically more challenging. Together, the abundance and potential function of many of these sORFs argues for the necessity of including sORFs in gene annotations and systematically characterizing these to understand their potential functional roles. In this review, we will focus on the high-throughput methods used in the detection and characterization of sORFs and discuss techniques for validation and functional characterization.
Collapse
Affiliation(s)
- Preeti Madhav Kute
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Omar Soukarieh
- Department of Molecular Epidemiology Of Vascular and Brain Disorders, INSERM, BPH, U1219, University of Bordeaux, Bordeaux, France
| | - Håkon Tjeldnes
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - David-Alexandre Trégouët
- Department of Molecular Epidemiology Of Vascular and Brain Disorders, INSERM, BPH, U1219, University of Bordeaux, Bordeaux, France
| | - Eivind Valen
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
- *Correspondence: Eivind Valen,
| |
Collapse
|
30
|
Licata NV, Cristofani R, Salomonsson S, Wilson KM, Kempthorne L, Vaizoglu D, D’Agostino VG, Pollini D, Loffredo R, Pancher M, Adami V, Bellosta P, Ratti A, Viero G, Quattrone A, Isaacs AM, Poletti A, Provenzani A. C9orf72 ALS/FTD dipeptide repeat protein levels are reduced by small molecules that inhibit PKA or enhance protein degradation. EMBO J 2022; 41:e105026. [PMID: 34791698 PMCID: PMC8724771 DOI: 10.15252/embj.2020105026] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 09/21/2021] [Accepted: 10/12/2021] [Indexed: 11/09/2022] Open
Abstract
Intronic GGGGCC (G4C2) hexanucleotide repeat expansion within the human C9orf72 gene represents the most common cause of familial forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9ALS/FTD). Repeat-associated non-AUG (RAN) translation of repeat-containing C9orf72 RNA results in the production of neurotoxic dipeptide-repeat proteins (DPRs). Here, we developed a high-throughput drug screen for the identification of positive and negative modulators of DPR levels. We found that HSP90 inhibitor geldanamycin and aldosterone antagonist spironolactone reduced DPR levels by promoting protein degradation via the proteasome and autophagy pathways respectively. Surprisingly, cAMP-elevating compounds boosting protein kinase A (PKA) activity increased DPR levels. Inhibition of PKA activity, by both pharmacological and genetic approaches, reduced DPR levels in cells and rescued pathological phenotypes in a Drosophila model of C9ALS/FTD. Moreover, knockdown of PKA-catalytic subunits correlated with reduced translation efficiency of DPRs, while the PKA inhibitor H89 reduced endogenous DPR levels in C9ALS/FTD patient-derived iPSC motor neurons. Together, our results suggest new and druggable pathways modulating DPR levels in C9ALS/FTD.
Collapse
Affiliation(s)
- Nausicaa V Licata
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Riccardo Cristofani
- Dipartimento di Scienze Farmacologiche e BiomolecolariUniversità degli Studi di MilanoMilanItaly
| | - Sally Salomonsson
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Katherine M Wilson
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Liam Kempthorne
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Deniz Vaizoglu
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Vito G D’Agostino
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Daniele Pollini
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Rosa Loffredo
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Michael Pancher
- HTS Core Facility, Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Valentina Adami
- HTS Core Facility, Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Paola Bellosta
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
- Department of MedicineNYU at Grossman School of MedicineNYUSA
| | - Antonia Ratti
- Department of NeurologyStroke Unit and Laboratory of NeuroscienceIstituto Auxologico Italiano, IRCCSMilanItaly
- Dipartimento di Biotecnologie Mediche e Medicina TraslazionaleUniversità degli Studi di MilanoMilanItaly
| | | | - Alessandro Quattrone
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Adrian M Isaacs
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e BiomolecolariUniversità degli Studi di MilanoMilanItaly
| | - Alessandro Provenzani
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| |
Collapse
|
31
|
Shirokikh NE. Translation complex stabilization on messenger RNA and footprint profiling to study the RNA responses and dynamics of protein biosynthesis in the cells. Crit Rev Biochem Mol Biol 2021; 57:261-304. [PMID: 34852690 DOI: 10.1080/10409238.2021.2006599] [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] [Indexed: 01/28/2023]
Abstract
During protein biosynthesis, ribosomes bind to messenger (m)RNA, locate its protein-coding information, and translate the nucleotide triplets sequentially as codons into the corresponding sequence of amino acids, forming proteins. Non-coding mRNA features, such as 5' and 3' untranslated regions (UTRs), start sites or stop codons of different efficiency, stretches of slower or faster code and nascent polypeptide interactions can alter the translation rates transcript-wise. Most of the homeostatic and signal response pathways of the cells converge on individual mRNA control, as well as alter the global translation output. Among the multitude of approaches to study translational control, one of the most powerful is to infer the locations of translational complexes on mRNA based on the mRNA fragments protected by these complexes from endonucleolytic hydrolysis, or footprints. Translation complex profiling by high-throughput sequencing of the footprints allows to quantify the transcript-wise, as well as global, alterations of translation, and uncover the underlying control mechanisms by attributing footprint locations and sizes to different configurations of the translational complexes. The accuracy of all footprint profiling approaches critically depends on the fidelity of footprint generation and many methods have emerged to preserve certain or multiple configurations of the translational complexes, often in challenging biological material. In this review, a systematic summary of approaches to stabilize translational complexes on mRNA for footprinting is presented and major findings are discussed. Future directions of translation footprint profiling are outlined, focusing on the fidelity and accuracy of inference of the native in vivo translation complex distribution on mRNA.
Collapse
Affiliation(s)
- Nikolay E Shirokikh
- Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| |
Collapse
|
32
|
iRQC, a surveillance pathway for 40S ribosomal quality control during mRNA translation initiation. Cell Rep 2021; 36:109642. [PMID: 34469731 DOI: 10.1016/j.celrep.2021.109642] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/15/2021] [Accepted: 08/10/2021] [Indexed: 12/31/2022] Open
Abstract
Post-translational modification of ribosomal proteins enables rapid and dynamic regulation of protein biogenesis. Site-specific ubiquitylation of 40S ribosomal proteins uS10 and eS10 plays a key role during ribosome-associated quality control (RQC). Distinct, and previously functionally ambiguous, ubiquitylation events on the 40S proteins uS3 and uS5 are induced by diverse proteostasis stressors that impact translation activity. Here, we identify the ubiquitin ligase RNF10 and the deubiquitylating enzyme USP10 as the key enzymes that regulate uS3 and uS5 ubiquitylation. Prolonged uS3 and uS5 ubiquitylation results in 40S, but not 60S, ribosomal protein degradation in a manner independent of canonical autophagy. We show that blocking progression of either scanning or elongating ribosomes past the start codon triggers site-specific ubiquitylation events on ribosomal proteins uS5 and uS3. This study identifies and characterizes a distinct arm in the RQC pathway, initiation RQC (iRQC), that acts on 40S ribosomes during translation initiation to modulate translation activity and capacity.
Collapse
|
33
|
Humans and other commonly used model organisms are resistant to cycloheximide-mediated biases in ribosome profiling experiments. Nat Commun 2021; 12:5094. [PMID: 34429433 PMCID: PMC8384890 DOI: 10.1038/s41467-021-25411-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 08/10/2021] [Indexed: 12/26/2022] Open
Abstract
Ribosome profiling measures genome-wide translation dynamics at sub-codon resolution. Cycloheximide (CHX), a widely used translation inhibitor to arrest ribosomes in these experiments, has been shown to induce biases in yeast, questioning its use. However, whether such biases are present in datasets of other organisms including humans is unknown. Here we compare different CHX-treatment conditions in human cells and yeast in parallel experiments using an optimized protocol. We find that human ribosomes are not susceptible to conformational restrictions by CHX, nor does it distort gene-level measurements of ribosome occupancy, measured decoding speed or the translational ramp. Furthermore, CHX-induced codon-specific biases on ribosome occupancy are not detectable in human cells or other model organisms. This shows that reported biases of CHX are species-specific and that CHX does not affect the outcome of ribosome profiling experiments in most settings. Our findings provide a solid framework to conduct and analyze ribosome profiling experiments. Ribosome profiling has become the gold standard to analyze mRNA translation dynamics, and the translation inhibitor cycloheximide (CHX) is often used in its application. Here the authors systematically demonstrate that CHX does not bias the outcome of ribosome profiling experiments in most organisms.
Collapse
|
34
|
Kovalak C, Donovan S, Bicknell AA, Metkar M, Moore MJ. Deep sequencing of pre-translational mRNPs reveals hidden flux through evolutionarily conserved alternative splicing nonsense-mediated decay pathways. Genome Biol 2021; 22:132. [PMID: 33941243 PMCID: PMC8091538 DOI: 10.1186/s13059-021-02309-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/02/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Alternative splicing, which generates multiple mRNA isoforms from single genes, is crucial for the regulation of eukaryotic gene expression. The flux through competing splicing pathways cannot be determined by traditional RNA-Seq, however, because different mRNA isoforms can have widely differing decay rates. Indeed, some mRNA isoforms with extremely short half-lives, such as those subject to translation-dependent nonsense-mediated decay (AS-NMD), may be completely overlooked in even the most extensive RNA-Seq analyses. RESULTS RNA immunoprecipitation in tandem (RIPiT) of exon junction complex components allows for purification of post-splicing mRNA-protein particles (mRNPs) not yet subject to translation (pre-translational mRNPs) and, therefore, translation-dependent mRNA decay. Here we compare exon junction complex RIPiT-Seq to whole cell RNA-Seq data from HEK293 cells. Consistent with expectation, the flux through known AS-NMD pathways is substantially higher than that captured by RNA-Seq. Our RIPiT-Seq also definitively demonstrates that the splicing machinery itself has no ability to detect reading frame. We identify thousands of previously unannotated splicing events; while many can be attributed to splicing noise, others are evolutionarily conserved events that produce new AS-NMD isoforms likely involved in maintenance of protein homeostasis. Several of these occur in genes whose overexpression has been linked to poor cancer prognosis. CONCLUSIONS Deep sequencing of RNAs in post-splicing, pre-translational mRNPs provides a means to identify and quantify splicing events without the confounding influence of differential mRNA decay. For many known AS-NMD targets, the nonsense-mediated decay-linked alternative splicing pathway predominates. Exon junction complex RIPiT-Seq also revealed numerous conserved but previously unannotated AS-NMD events.
Collapse
Affiliation(s)
- Carrie Kovalak
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Scott Donovan
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA
| | - Alicia A Bicknell
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA
| | - Mihir Metkar
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA
| | - Melissa J Moore
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA.
| |
Collapse
|
35
|
Performing Ribosome Profiling to Assess Translation in Vegetative and Meiotic Yeast Cells. Methods Mol Biol 2021; 2252:89-125. [PMID: 33765272 DOI: 10.1007/978-1-0716-1150-0_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ribosome profiling, first developed in 2009, is the gold standard for quantifying and qualifying changes to translation genome-wide (Ingolia et al., Science, 2009). Though first designed and optimized in vegetative budding yeast, it has since been modified and specialized for use in diverse cellular states in yeast, as well as in bacteria, plants, human cells, and many other organisms (Ingolia et al. Science, 2009, reviewed in (Ingolia et al., Cold Spring Harb Perspect Biol, 2019; Brar and Weissman, Nat Rev Mol Cell Biol, 2015)). Here we report the current ribosome profiling protocol used in our lab to study genome-wide changes to translation in budding yeast undergoing the developmental process of meiosis (Brar et al., Science, 2012; Cheng et al., Cell, 2018). We describe this protocol in detail, including the following steps: collection and flash freezing samples, cell lysis and extract preparation, sucrose gradient centrifugation and monosome collection, RNA extraction, library preparation, and library quality control. Almost every step presented here should be directly applicable to performing ribosome profiling in other eukaryotic cell types or cell states.
Collapse
|
36
|
Higdon AL, Brar GA. Rules are made to be broken: a "simple" model organism reveals the complexity of gene regulation. Curr Genet 2020; 67:49-56. [PMID: 33130938 DOI: 10.1007/s00294-020-01121-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 11/27/2022]
Abstract
Global methods for assaying translation have greatly improved our understanding of the protein-coding capacity of the genome. In particular, it is now possible to perform genome-wide and condition-specific identification of translation initiation sites through modified ribosome profiling methods that selectively capture initiating ribosomes. Here we discuss our recent study applying such an approach to meiotic and mitotic timepoints in the simple eukaryote, budding yeast, as an example of the surprising diversity of protein products-many of which are non-canonical-that can be revealed by such methods. We also highlight several key challenges in studying non-canonical protein isoforms that have precluded their prior systematic discovery. A growing body of work supports expanded use of empirical protein-coding region identification, which can help relieve some of the limitations and biases inherent to traditional genome annotation approaches. Our study also argues for the adoption of less static views of gene identity and a broader framework for considering the translational capacity of the genome.
Collapse
Affiliation(s)
- Andrea L Higdon
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
- Center for Computational Biology, University of California, Berkeley, CA, 94720, USA
| | - Gloria A Brar
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA.
- Center for Computational Biology, University of California, Berkeley, CA, 94720, USA.
| |
Collapse
|
37
|
Mangano K, Florin T, Shao X, Klepacki D, Chelysheva I, Ignatova Z, Gao Y, Mankin AS, Vázquez-Laslop N. Genome-wide effects of the antimicrobial peptide apidaecin on translation termination in bacteria. eLife 2020; 9:e62655. [PMID: 33031031 PMCID: PMC7544508 DOI: 10.7554/elife.62655] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 09/20/2020] [Indexed: 12/16/2022] Open
Abstract
Biochemical studies suggested that the antimicrobial peptide apidaecin (Api) inhibits protein synthesis by binding in the nascent peptide exit tunnel and trapping the release factor associated with a terminating ribosome. The mode of Api action in bacterial cells had remained unknown. Here genome-wide analysis reveals that in bacteria, Api arrests translating ribosomes at stop codons and causes pronounced queuing of the trailing ribosomes. By sequestering the available release factors, Api promotes pervasive stop codon bypass, leading to the expression of proteins with C-terminal extensions. Api-mediated translation arrest leads to the futile activation of the ribosome rescue systems. Understanding the unique mechanism of Api action in living cells may facilitate the development of new medicines and research tools for genome exploration.
Collapse
Affiliation(s)
- Kyle Mangano
- Center for Biomolecular Sciences, University of Illinois at ChicagoChicagoUnited States
- Department of Pharmaceutical Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Tanja Florin
- Center for Biomolecular Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Xinhao Shao
- Department of Pharmaceutical Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Dorota Klepacki
- Center for Biomolecular Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Irina Chelysheva
- Institute of Biochemistry and Molecular Biology, University of HamburgHamburgGermany
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of HamburgHamburgGermany
| | - Yu Gao
- Department of Pharmaceutical Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Alexander S Mankin
- Center for Biomolecular Sciences, University of Illinois at ChicagoChicagoUnited States
- Department of Pharmaceutical Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Nora Vázquez-Laslop
- Center for Biomolecular Sciences, University of Illinois at ChicagoChicagoUnited States
- Department of Pharmaceutical Sciences, University of Illinois at ChicagoChicagoUnited States
| |
Collapse
|
38
|
Li YR, Liu MJ. Prevalence of alternative AUG and non-AUG translation initiators and their regulatory effects across plants. Genome Res 2020; 30:1418-1433. [PMID: 32973042 PMCID: PMC7605272 DOI: 10.1101/gr.261834.120] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
Translation initiation is a key step determining protein synthesis. Studies have uncovered a number of alternative translation initiation sites (TISs) in mammalian mRNAs and showed their roles in reshaping the proteome. However, the extent to which alternative TISs affect gene expression across plants remains largely unclear. Here, by profiling initiating ribosome positions, we globally identified in vivo TISs in tomato and Arabidopsis and found thousands of genes with more than one TIS. Of the identified TISs, >19% and >20% were located at unannotated AUG and non-AUG sites, respectively. CUG and ACG were the most frequently observed codons at non-AUG TISs, a phenomenon also found in mammals. In addition, although alternative TISs were usually found in both orthologous genes, the TIS sequences were not conserved, suggesting the conservation of alternative initiation mechanisms but flexibility in using TISs. Unlike upstream AUG TISs, the presence of upstream non-AUG TISs was not correlated with the translational repression of main open reading frames, a pattern observed across plants. Also, the generation of proteins with diverse N-terminal regions through the use of alternative TISs contributes to differential subcellular localization, as mutating alternative TISs resulted in the loss of organelle localization. Our findings uncovered the hidden coding potential of plant genomes and, importantly, the constraint and flexibility of translational initiation mechanisms in the regulation of gene expression across plant species.
Collapse
Affiliation(s)
- Ya-Ru Li
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan
| | - Ming-Jung Liu
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan.,Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| |
Collapse
|
39
|
Akirtava C, McManus CJ. Control of translation by eukaryotic mRNA transcript leaders-Insights from high-throughput assays and computational modeling. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1623. [PMID: 32869519 DOI: 10.1002/wrna.1623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/23/2020] [Accepted: 07/30/2020] [Indexed: 12/21/2022]
Abstract
Eukaryotic gene expression is tightly regulated during translation of mRNA to protein. Mis-regulation of translation can lead to aberrant proteins which accumulate in cancers and cause neurodegenerative diseases. Foundational studies on model genes established fundamental roles for mRNA 5' transcript leader (TL) sequences in controlling ribosome recruitment, scanning, and initiation. TL cis-regulatory elements and their corresponding trans-acting factors control cap-dependent initiation under unstressed conditions. Under stress, cap-dependent initiation is suppressed, and specific mRNA structures and sequences promote translation of stress-responsive transcripts to remodel the proteome. In this review, we summarize current knowledge of TL functions in translation initiation. We focus on insights from high-throughput analyses of ribosome occupancy, mRNA structure, RNA Binding Protein occupancy, and massively parallel reporter assays. These data-driven approaches, coupled with computational analyses and modeling, have paved the way for a comprehensive understanding of TL functions. Finally, we will discuss areas of future research on the roles of mRNA sequences and structures in translation. This article is categorized under: Translation > Translation Mechanisms RNA Evolution and Genomics > Computational Analyses of RNA RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
Collapse
Affiliation(s)
- Christina Akirtava
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Charles Joel McManus
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Computational Biology Department, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
40
|
Bohlen J, Fenzl K, Kramer G, Bukau B, Teleman AA. Selective 40S Footprinting Reveals Cap-Tethered Ribosome Scanning in Human Cells. Mol Cell 2020; 79:561-574.e5. [DOI: 10.1016/j.molcel.2020.06.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/10/2020] [Accepted: 05/18/2020] [Indexed: 11/27/2022]
|
41
|
Wang P, Xu L, Gao Y, Han R. BEON: A Functional Fluorescence Reporter for Quantification and Enrichment of Adenine Base-Editing Activity. Mol Ther 2020; 28:1696-1705. [PMID: 32353322 PMCID: PMC7335737 DOI: 10.1016/j.ymthe.2020.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/12/2020] [Accepted: 04/09/2020] [Indexed: 12/11/2022] Open
Abstract
Adenine base editor (ABE) is a new generation of genome-editing technology through fusion of Cas9 nickase with an evolved E. coli TadA (TadA∗) and holds great promise as novel genome-editing therapeutics for treating genetic disorders. ABEs can directly convert A-T to G-C in specific genomic DNA targets without introducing double-strand breaks (DSBs). We recently showed that computer program-assisted analysis of Sanger sequencing traces can be used as a low-cost and rapid alternative of deep sequencing to assess base-editing outcomes. Here we developed a rapid fluorescence-based reporter assay (Base Editing ON [BEON]) to quantify ABE efficiency. The assay relies on the restoration of the downstream green fluorescent protein (GFP) in ABE-mediated editing of a stop codon located within the guide RNA (gRNA). We showed that this assay can be used to screen for effective ABE variants, characterize the protospacer adjacent motif (PAM) requirement of a novel NNG-targeting ABE based on ScCas9, and enrich for edited cells. Finally, we demonstrated that the reporter assay allowed us to assess the feasibility of ABE editing to correct point mutations associated with dysferlinopathy. Taken together, the BEON assay would facilitate and simplify the studies with ABEs.
Collapse
Affiliation(s)
- Peipei Wang
- Department of Surgery, Davis Heart and Lung Research Institute, Biomedical Sciences Graduate Program, Biophysics Graduate Program, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Li Xu
- Department of Surgery, Davis Heart and Lung Research Institute, Biomedical Sciences Graduate Program, Biophysics Graduate Program, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Yandi Gao
- Department of Surgery, Davis Heart and Lung Research Institute, Biomedical Sciences Graduate Program, Biophysics Graduate Program, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Renzhi Han
- Department of Surgery, Davis Heart and Lung Research Institute, Biomedical Sciences Graduate Program, Biophysics Graduate Program, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
| |
Collapse
|
42
|
Tuck AC, Rankova A, Arpat AB, Liechti LA, Hess D, Iesmantavicius V, Castelo-Szekely V, Gatfield D, Bühler M. Mammalian RNA Decay Pathways Are Highly Specialized and Widely Linked to Translation. Mol Cell 2020; 77:1222-1236.e13. [PMID: 32048998 PMCID: PMC7083229 DOI: 10.1016/j.molcel.2020.01.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/11/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022]
Abstract
RNA decay is crucial for mRNA turnover and surveillance and misregulated in many diseases. This complex system is challenging to study, particularly in mammals, where it remains unclear whether decay pathways perform specialized versus redundant roles. Cytoplasmic pathways and links to translation are particularly enigmatic. By directly profiling decay factor targets and normal versus aberrant translation in mouse embryonic stem cells (mESCs), we uncovered extensive decay pathway specialization and crosstalk with translation. XRN1 (5'-3') mediates cytoplasmic bulk mRNA turnover whereas SKIV2L (3'-5') is universally recruited by ribosomes, tackling aberrant translation and sometimes modulating mRNA abundance. Further exploring translation surveillance revealed AVEN and FOCAD as SKIV2L interactors. AVEN prevents ribosome stalls at structured regions, which otherwise require SKIV2L for clearance. This pathway is crucial for histone translation, upstream open reading frame (uORF) regulation, and counteracting ribosome arrest on small ORFs. In summary, we uncovered key targets, components, and functions of mammalian RNA decay pathways and extensive coupling to translation.
Collapse
Affiliation(s)
- Alex Charles Tuck
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Aneliya Rankova
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Alaaddin Bulak Arpat
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Luz Angelica Liechti
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Vytautas Iesmantavicius
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | | | - David Gatfield
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Petersplatz 10, 4003 Basel, Switzerland.
| |
Collapse
|
43
|
Tatomer DC, Wilusz JE. Attenuation of Eukaryotic Protein-Coding Gene Expression via Premature Transcription Termination. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:83-93. [PMID: 32086332 DOI: 10.1101/sqb.2019.84.039644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A complex network of RNA transcripts is generated from eukaryotic genomes, many of which are processed in unexpected ways. Here, we highlight how premature transcription termination events at protein-coding gene loci can simultaneously lead to the generation of short RNAs and attenuate production of full-length mRNA transcripts. We recently showed that the Integrator (Int) complex can be selectively recruited to protein-coding gene loci, including Drosophila metallothionein A (MtnA), where the IntS11 RNA endonuclease cleaves nascent transcripts near their 5' ends. Such premature termination events catalyzed by Integrator can repress the expression of some full-length mRNAs by more than 100-fold. Transcription at small nuclear RNA (snRNA) loci is likewise terminated by Integrator cleavage, but protein-coding and snRNA gene loci have notably distinct dependencies on Integrator subunits. Additional mechanisms that attenuate eukaryotic gene outputs via premature termination have been discovered, including by the cleavage and polyadenylation machinery in a manner controlled by U1 snRNP. These mechanisms appear to function broadly across the transcriptome. This suggests that synthesis of full-length transcripts is not always the default option and that premature termination events can lead to a variety of transcripts, some of which may have important and unexpected biological functions.
Collapse
Affiliation(s)
- Deirdre C Tatomer
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| |
Collapse
|
44
|
Manjunath H, Zhang H, Rehfeld F, Han J, Chang TC, Mendell JT. Suppression of Ribosomal Pausing by eIF5A Is Necessary to Maintain the Fidelity of Start Codon Selection. Cell Rep 2019; 29:3134-3146.e6. [PMID: 31801078 PMCID: PMC6917043 DOI: 10.1016/j.celrep.2019.10.129] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022] Open
Abstract
Sequences within 5' UTRs dictate the site and efficiency of translation initiation. In this study, an unbiased screen designed to interrogate the 5' UTR-mediated regulation of the growth-promoting gene MYC unexpectedly revealed the ribosomal pause relief factor eIF5A as a regulator of translation initiation codon selection. Depletion of eIF5A enhances upstream translation within 5' UTRs across yeast and human transcriptomes, including on the MYC transcript, where this results in increased production of an N-terminally extended protein. Furthermore, ribosome profiling experiments established that the function of eIF5A as a suppressor of ribosomal pausing at sites of suboptimal peptide bond formation is conserved in human cells. We present evidence that proximal ribosomal pausing on a transcript triggers enhanced use of upstream suboptimal or non-canonical initiation codons. Thus, we propose that eIF5A functions not only to maintain efficient translation elongation in eukaryotic cells but also to maintain the fidelity of translation initiation.
Collapse
Affiliation(s)
- Hema Manjunath
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - He Zhang
- Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA; Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA
| | - Frederick Rehfeld
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Jaeil Han
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Joshua T Mendell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
45
|
mRNA structure regulates protein expression through changes in functional half-life. Proc Natl Acad Sci U S A 2019; 116:24075-24083. [PMID: 31712433 PMCID: PMC6883848 DOI: 10.1073/pnas.1908052116] [Citation(s) in RCA: 265] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Despite widespread recognition that RNA is inherently structured, the interplay between local and global mRNA secondary structure (particularly in the coding region) and overall protein expression has not been thoroughly explored. Our work uses 2 approaches to disentangle the regulatory roles of mRNA primary sequence and secondary structure: global substitution with modified nucleotides and computational sequence design. By fitting detailed kinetic expression data to mathematical models, we show that secondary structure can increase mRNA half-life independent of codon usage. These findings have significant implications for both translational regulation of endogenous mRNAs and the emerging field of mRNA therapeutics. Messenger RNAs (mRNAs) encode information in both their primary sequence and their higher order structure. The independent contributions of factors like codon usage and secondary structure to regulating protein expression are difficult to establish as they are often highly correlated in endogenous sequences. Here, we used 2 approaches, global inclusion of modified nucleotides and rational sequence design of exogenously delivered constructs, to understand the role of mRNA secondary structure independent from codon usage. Unexpectedly, highly expressed mRNAs contained a highly structured coding sequence (CDS). Modified nucleotides that stabilize mRNA secondary structure enabled high expression across a wide variety of primary sequences. Using a set of eGFP mRNAs with independently altered codon usage and CDS structure, we find that the structure of the CDS regulates protein expression through changes in functional mRNA half-life (i.e., mRNA being actively translated). This work highlights an underappreciated role of mRNA secondary structure in the regulation of mRNA stability.
Collapse
|
46
|
Hui KK, Chen YK, Endo R, Tanaka M. Translation from the Ribosome to the Clinic: Implication in Neurological Disorders and New Perspectives from Recent Advances. Biomolecules 2019; 9:E680. [PMID: 31683805 PMCID: PMC6920867 DOI: 10.3390/biom9110680] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/27/2019] [Accepted: 10/29/2019] [Indexed: 12/12/2022] Open
Abstract
De novo protein synthesis by the ribosome and its multitude of co-factors must occur in a tightly regulated manner to ensure that the correct proteins are produced accurately at the right time and, in some cases, also in the proper location. With novel techniques such as ribosome profiling and cryogenic electron microscopy, our understanding of this basic biological process is better than ever and continues to grow. Concurrently, increasing attention is focused on how translational regulation in the brain may be disrupted during the progression of various neurological disorders. In fact, translational dysregulation is now recognized as the de facto pathogenic cause for some disorders. Novel mechanisms including ribosome stalling, ribosome-associated quality control, and liquid-liquid phase separation are closely linked to translational regulation, and may thus be involved in the pathogenic process. The relationships between translational dysregulation and neurological disorders, as well as the ways through which we may be able to reverse those detrimental effects, will be examined in this review.
Collapse
Affiliation(s)
- Kelvin K Hui
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| | - Yi-Kai Chen
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| | - Ryo Endo
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| |
Collapse
|
47
|
Green KM, Sheth UJ, Flores BN, Wright SE, Sutter AB, Kearse MG, Barmada SJ, Ivanova MI, Todd PK. High-throughput screening yields several small-molecule inhibitors of repeat-associated non-AUG translation. J Biol Chem 2019; 294:18624-18638. [PMID: 31649034 DOI: 10.1074/jbc.ra119.009951] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 10/16/2019] [Indexed: 12/18/2022] Open
Abstract
Repeat-associated non-AUG (RAN) translation is a noncanonical translation initiation event that occurs at nucleotide-repeat expansion mutations that are associated with several neurodegenerative diseases, including fragile X-associated tremor ataxia syndrome (FXTAS), ALS, and frontotemporal dementia (FTD). Translation of expanded repeats produces toxic proteins that accumulate in human brains and contribute to disease pathogenesis. Consequently, RAN translation constitutes a potentially important therapeutic target for managing multiple neurodegenerative disorders. Here, we adapted a previously developed RAN translation assay to a high-throughput format to screen 3,253 bioactive compounds for inhibition of RAN translation of expanded CGG repeats associated with FXTAS. We identified five diverse small molecules that dose-dependently inhibited CGG RAN translation, while relatively sparing canonical translation. All five compounds also inhibited RAN translation of expanded GGGGCC repeats associated with ALS and FTD. Using CD and native gel analyses, we found evidence that three of these compounds, BIX01294, CP-31398, and propidium iodide, bind directly to the repeat RNAs. These findings provide proof-of-principle supporting the development of selective small-molecule RAN translation inhibitors that act across multiple disease-causing repeats.
Collapse
Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Udit J Sheth
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Brittany N Flores
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Alexandra B Sutter
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Michael G Kearse
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Department of Biological Chemistry and Pharmacology, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109; Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan 48105.
| |
Collapse
|
48
|
Migration of Small Ribosomal Subunits on the 5' Untranslated Regions of Capped Messenger RNA. Int J Mol Sci 2019; 20:ijms20184464. [PMID: 31510048 PMCID: PMC6769788 DOI: 10.3390/ijms20184464] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/01/2019] [Accepted: 09/05/2019] [Indexed: 12/12/2022] Open
Abstract
Several control mechanisms of eukaryotic gene expression target the initiation step of mRNA translation. The canonical translation initiation pathway begins with cap-dependent attachment of the small ribosomal subunit (SSU) to the messenger ribonucleic acid (mRNA) followed by an energy-dependent, sequential ‘scanning’ of the 5′ untranslated regions (UTRs). Scanning through the 5′UTR requires the adenosine triphosphate (ATP)-dependent RNA helicase eukaryotic initiation factor (eIF) 4A and its efficiency contributes to the specific rate of protein synthesis. Thus, understanding the molecular details of the scanning mechanism remains a priority task for the field. Here, we studied the effects of inhibiting ATP-dependent translation and eIF4A in cell-free translation and reconstituted initiation reactions programmed with capped mRNAs featuring different 5′UTRs. An aptamer that blocks eIF4A in an inactive state away from mRNA inhibited translation of capped mRNA with the moderately structured β-globin sequences in the 5′UTR but not that of an mRNA with a poly(A) sequence as the 5′UTR. By contrast, the nonhydrolysable ATP analogue β,γ-imidoadenosine 5′-triphosphate (AMP-PNP) inhibited translation irrespective of the 5′UTR sequence, suggesting that complexes that contain ATP-binding proteins in their ATP-bound form can obstruct and/or actively block progression of ribosome recruitment and/or scanning on mRNA. Further, using primer extension inhibition to locate SSUs on mRNA (‘toeprinting’), we identify an SSU complex which inhibits primer extension approximately eight nucleotides upstream from the usual toeprinting stop generated by SSUs positioned over the start codon. This ‘−8 nt toeprint’ was seen with mRNA 5′UTRs of different length, sequence and structure potential. Importantly, the ‘−8 nt toeprint’ was strongly stimulated by the presence of the cap on the mRNA, as well as the presence of eIFs 4F, 4A/4B and ATP, implying active scanning. We assembled cell-free translation reactions with capped mRNA featuring an extended 5′UTR and used cycloheximide to arrest elongating ribosomes at the start codon. Impeding scanning through the 5′UTR in this system with elevated magnesium and AMP-PNP (similar to the toeprinting conditions), we visualised assemblies consisting of several SSUs together with one full ribosome by electron microscopy, suggesting direct detection of scanning intermediates. Collectively, our data provide additional biochemical, molecular and physical evidence to underpin the scanning model of translation initiation in eukaryotes.
Collapse
|