1
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Kadonosawa Y, Yokoyama M, Tatara Y, Fujita T, Yokoyama Y. Overexpression of carbonyl reductase 1 in ovarian cancer cells suppresses proliferation and activates the eIF2 signaling pathway. Oncol Lett 2024; 28:359. [PMID: 38881711 PMCID: PMC11177172 DOI: 10.3892/ol.2024.14492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 04/16/2024] [Indexed: 06/18/2024] Open
Abstract
High expression of carbonyl reductase 1 (CBR1) protein in ovarian cancer cells inhibits tumor growth and metastasis. However, the underlying mechanism is unknown. To investigate the mechanism by which CBR1 suppresses tumor growth, the present study generated ovarian cancer cells that constitutively overexpress human CBR1 (hCBR1) protein. Ovarian cancer cell lines (OVCAR-3 and SK-OV-3) were transfected with a plasmid encoding hCBR1, followed by selection with G418 to isolate hCBR1-overexpressing lines. The proliferation rates of hCBR1-overexpressing cells were then compared with those of negative control and wild-type cells. Overexpression of hCBR1 led to significant inhibition of proliferation (P<0.05). Subsequently, to investigate changes in intracellular signaling pathways, cellular proteins were extracted and subjected to proteome analysis using liquid chromatography followed by mass spectrometry. There was an inverse correlation between CBR1 protein expression and cell proliferation. In addition, Ingenuity Pathway Analysis of hCBR1-overexpressing cell lines was performed, which revealed changes in the expression of proteins involved in signaling pathways related to growth regulation. Of these, the eukaryotic translation initiation factor 2 (eIF2) signaling pathway was upregulated most prominently. Thus, alterations in multiple tumor-related signaling pathways, including eIF2 signaling, may lead to growth suppression. Taken together, the present data may lead to the development of new drugs that target CBR1 and related signaling pathways, thereby improving outcomes for patients with ovarian cancer.
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Affiliation(s)
- Yuka Kadonosawa
- Department of Obstetrics and Gynecology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Minako Yokoyama
- Department of Obstetrics and Gynecology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Yota Tatara
- Department of Stress Response Science, Center for Advanced Medical Research, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Toshitsugu Fujita
- Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Yoshihito Yokoyama
- Department of Obstetrics and Gynecology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
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2
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Fernandez SG, Ferguson L, Ingolia NT. Ribosome rescue factor PELOTA modulates translation start site choice for C/EBPα protein isoforms. Life Sci Alliance 2024; 7:e202302501. [PMID: 38803235 PMCID: PMC11109482 DOI: 10.26508/lsa.202302501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 05/29/2024] Open
Abstract
Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the developmental transcription factor CCAAT/enhancer-binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This choice between alternative start sites depends on sequence features of the CEBPA transcript, including a regulatory uORF, but the molecular basis is not fully understood. Here, we identify the factors that affect C/EBPα isoform choice using a sensitive and quantitative two-color fluorescent reporter coupled with CRISPRi screening. Our screen uncovered a role of the ribosome rescue factor PELOTA (PELO) in promoting the expression of the longer C/EBPα isoform by directly removing inhibitory unrecycled ribosomes and through indirect effects mediated by the mechanistic target of rapamycin kinase. Our work uncovers further links between ribosome recycling and translation reinitiation that regulate a key transcription factor, with implications for normal hematopoiesis and leukemogenesis.
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Affiliation(s)
- Samantha G Fernandez
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Lucas Ferguson
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- https://ror.org/01an7q238 Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Nicholas T Ingolia
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- https://ror.org/01an7q238 Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
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3
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Kim KQ, Nanjaraj Urs AN, Lasehinde V, Greenlaw AC, Hudson BH, Zaher HS. eIF4F complex dynamics are important for the activation of the integrated stress response. Mol Cell 2024; 84:2135-2151.e7. [PMID: 38848692 PMCID: PMC11189614 DOI: 10.1016/j.molcel.2024.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/08/2023] [Accepted: 04/19/2024] [Indexed: 06/09/2024]
Abstract
In response to stress, eukaryotes activate the integrated stress response (ISR) via phosphorylation of eIF2α to promote the translation of pro-survival effector genes, such as GCN4 in yeast. Complementing the ISR is the target of rapamycin (TOR) pathway, which regulates eIF4E function. Here, we probe translational control in the absence of eIF4E in Saccharomyces cerevisiae. Intriguingly, we find that loss of eIF4E leads to de-repression of GCN4 translation. In addition, we find that de-repression of GCN4 translation is accompanied by neither eIF2α phosphorylation nor reduction in initiator ternary complex (TC). Our data suggest that when eIF4E levels are depleted, GCN4 translation is de-repressed via a unique mechanism that may involve faster scanning by the small ribosome subunit due to increased local concentration of eIF4A. Overall, our findings suggest that relative levels of eIF4F components are key to ribosome dynamics and may play important roles in translational control of gene expression.
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Affiliation(s)
- Kyusik Q Kim
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | | | - Victor Lasehinde
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Alison C Greenlaw
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Benjamin H Hudson
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Hani S Zaher
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
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4
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Weiss B, Dikstein R. Unraveling the landscapes and regulation of scanning, leaky scanning, and 48S initiation complex conformations. Cell Rep 2024; 43:114126. [PMID: 38630588 DOI: 10.1016/j.celrep.2024.114126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 01/19/2024] [Accepted: 04/02/2024] [Indexed: 04/19/2024] Open
Abstract
Scanning and initiation are critical steps in translation. Here, we utilized translation complex profiling (TCP-seq) to investigate 48S organization and eIF4G1-eIF1 inhibition impact. We provide global views of scanning and leaky scanning, uncovering a central role of eIF4G1-eIF1 in their regulation. We confirm AUG context importance, with non-leaky genes featuring a Kozak context and cytosine at positions -1 and +5. Capturing 48S complexes associated with eIF1, eIF4G1, eIF3, and eIF2 through selective TCP-seq revealed that the eIF3-scanning ribosome is highly vulnerable to eIF4G1-eIF1 inhibition, and eIF1 tends to dissociate upon AUG recognition. Initiation-site footprint analysis revealed a class spanning -12 to +18/19 from the AUG, representing the entire 48S and enriched with eIF2, eIF1, and eIF4G1, indicative of early initiation. Another eIF3-dependent class extends up to +26 and exhibits reduced eIF2 and eIF4G1 association, suggesting a late/alternative initiation complex. Our analysis provides an overview of scanning, initiation, and evidence for conformational rearrangements in vivo.
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Affiliation(s)
- Benjamin Weiss
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
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5
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Lama-Diaz T, Blanco MG. Alternative translation initiation by ribosomal leaky scanning produces multiple isoforms of the Pif1 helicase. Nucleic Acids Res 2024:gkae400. [PMID: 38783074 DOI: 10.1093/nar/gkae400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/24/2024] [Accepted: 05/01/2024] [Indexed: 05/25/2024] Open
Abstract
In budding yeast, the integrity of both the nuclear and mitochondrial genomes relies on dual-targeted isoforms of the conserved Pif1 helicase, generated by alternative translation initiation (ATI) of PIF1 mRNA from two consecutive AUG codons flanking a mitochondrial targeting signal. Here, we demonstrate that ribosomal leaky scanning is the specific ATI mechanism that produces not only these, but also novel, previously uncharacterized Pif1 isoforms. Both in-frame, downstream AUGs as well as near-cognate start codons contribute to the generation of these alternative isoforms. This has crucial implications for the rational design of genuine separation-of-function alleles and provides an explanation for the suboptimal behaviour of the widely employed mitochondrial- (pif1-m1) and nuclear-deficient (pif1-m2) alleles, with mutations in the first or second AUG codon, respectively. We have taken advantage of this refined model to develop improved versions of these alleles, which will serve as valuable tools to elucidate novel functions of this helicase and to disambiguate previously described genetic interactions of PIF1 in the context of nuclear and mitochondrial genome stability.
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Affiliation(s)
- Tomas Lama-Diaz
- Department of Biochemistry and Molecular Biology, CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), Santiago de Compostela, A Coruña 15782, Spain
| | - Miguel G Blanco
- Department of Biochemistry and Molecular Biology, CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), Santiago de Compostela, A Coruña 15782, Spain
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6
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Boyer JA, Sharma M, Dorso MA, Mai N, Amor C, Reiter JM, Kannan R, Gadal S, Xu J, Miele M, Li Z, Chen X, Chang Q, Pareja F, Worland S, Warner D, Sperry S, Chiang GG, Thompson PA, Yang G, Ouerfelli O, de Stanchina E, Wendel HG, Rosen EY, Chandarlapaty S, Rosen N. eIF4A controls translation of estrogen receptor alpha and is a therapeutic target in advanced breast cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593195. [PMID: 38766126 PMCID: PMC11100762 DOI: 10.1101/2024.05.08.593195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The majority of human breast cancers are dependent on hormone-stimulated estrogen receptor alpha (ER) and are sensitive to its inhibition. Treatment resistance arises in most advanced cancers due to genetic alterations that promote ligand independent activation of ER itself or ER target genes. Whereas re-targeting of the ER ligand binding domain (LBD) with newer ER antagonists can work in some cases, these drugs are largely ineffective in many genetic backgrounds including ER fusions that lose the LBD or in cancers that hyperactivate ER targets. By identifying the mechanism of ER translation, we herein present an alternative strategy to target ER and difficult to treat ER variants. We find that ER translation is cap-independent and mTOR inhibitor insensitive, but dependent on 5' UTR elements and sensitive to pharmacologic inhibition of the translation initiation factor eIF4A, an mRNA helicase. EIF4A inhibition rapidly reduces expression of ER and short-lived targets of ER such as cyclin D1 and other components of the cyclin D-CDK complex in breast cancer cells. These effects translate into suppression of growth of a variety of ligand-independent breast cancer models including those driven by ER fusion proteins that lack the ligand binding site. The efficacy of eIF4A inhibition is enhanced when it is combined with fulvestrant-an ER degrader. Concomitant inhibition of ER synthesis and induction of its degradation causes synergistic and durable inhibition of ER expression and tumor growth. The clinical importance of these findings is confirmed by results of an early clinical trial (NCT04092673) of the selective eIF4A inhibitor zotatifin in patients with estrogen receptor positive metastatic breast cancer. Multiple clinical responses have been observed on combination therapy including durable regressions. These data suggest that eIF4A inhibition could be a useful new strategy for treating advanced ER+ breast cancer.
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Affiliation(s)
- Jacob A. Boyer
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
- Program in Molecular Pharmacology, Department of Medicine, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Malvika Sharma
- Program in Molecular Pharmacology, Department of Medicine, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA
| | - Madeline A. Dorso
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Nicholas Mai
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Corina Amor
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
- Department of Cancer Biology and Genetics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jason M. Reiter
- Program in Molecular Pharmacology, Department of Medicine, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA
| | - Ram Kannan
- Department of Cancer Biology and Genetics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Sunyana Gadal
- Program in Molecular Pharmacology, Department of Medicine, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA
| | - Jianing Xu
- Program in Molecular Pharmacology, Department of Medicine, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA
| | - Matthew Miele
- Microchemistry and Proteomics Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zhuoning Li
- Microchemistry and Proteomics Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Xiaoping Chen
- Antitumor Assessment Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 11065, USA
| | - Qing Chang
- Antitumor Assessment Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 11065, USA
| | - Fresia Pareja
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Stephan Worland
- Department of Cancer Biology, eFFECTOR Therapeutics, Inc., San Diego, CA, United States
| | - Douglas Warner
- Department of Cancer Biology, eFFECTOR Therapeutics, Inc., San Diego, CA, United States
| | - Sam Sperry
- Department of Cancer Biology, eFFECTOR Therapeutics, Inc., San Diego, CA, United States
| | - Gary G. Chiang
- Department of Cancer Biology, eFFECTOR Therapeutics, Inc., San Diego, CA, United States
| | - Peggy A. Thompson
- Department of Cancer Biology, eFFECTOR Therapeutics, Inc., San Diego, CA, United States
| | - Guangli Yang
- The Organic Synthesis Core Facility, MSK, New York, NY, USA
| | | | - Elisa de Stanchina
- Antitumor Assessment Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 11065, USA
| | - Hans-Guido Wendel
- Department of Cancer Biology and Genetics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ezra Y. Rosen
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Sarat Chandarlapaty
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Neal Rosen
- Program in Molecular Pharmacology, Department of Medicine, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA
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7
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Váchová L, Plocek V, Maršíková J, Rešetárová S, Hatáková L, Palková Z. Differential stability of Gcn4p controls its cell-specific activity in differentiated yeast colonies. mBio 2024; 15:e0068924. [PMID: 38624209 PMCID: PMC11077963 DOI: 10.1128/mbio.00689-24] [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: 03/07/2024] [Accepted: 03/22/2024] [Indexed: 04/17/2024] Open
Abstract
Gcn4p belongs to conserved AP-1 transcription factors involved in many cellular processes, including cell proliferation, stress response, and nutrient availability in yeast and mammals. AP-1 activities are regulated at different levels, such as translational activation or protein degradation, which increases the variability of regulation under different conditions. Gcn4p activity in unstructured yeast liquid cultures increases upon amino acid deficiency and is rapidly eliminated upon amino acid excess. Gcn2p kinase is the major described regulator of Gcn4p that enables GCN4 mRNA translation via the uORFs mechanism. Here, we show that Gcn4p is specifically active in U cells in the upper regions and inactive in L cells in the lower regions of differentiated colonies. Using in situ microscopy in combination with analysis of mutants and strains with GFP at different positions in the translational regulatory region of Gcn4p, we show that cell-specific Gcn4p activity is independent of Gcn2p or other translational or transcriptional regulation. Genetically, biochemically, and microscopically, we identified cell-specific proteasomal degradation as a key mechanism that diversifies Gcn4p function between U and L cells. The identified regulation leading to active Gcn4p in U cells with amino acids and efficient degradation in starved L cells differs from known regulations of Gcn4p in yeast but shows similarities to the activity of AP-1 ATF4 in mammals during insulin signaling. These findings may open new avenues for understanding the parallel activities of Gcn4p/ATF4 and reveal a novel biological role for cell type-specific regulation of proteasome-dependent degradation.IMPORTANCEIn nature, microbes usually live in spatially structured communities and differentiate into precisely localized, functionally specialized cells. The coordinated interplay of cells and their response to environmental changes, such as starvation, followed by metabolic adaptation, is critical for the survival of the entire community. Transcription factor Gcn4p is responsible for yeast adaptation under amino acid starvation in liquid cultures, and its activity is regulated mainly at the level of translation involving Gcn2p kinase. Whether Gcn4p functions in structured communities was unknown. We show that translational regulation of Gcn4p plays no role in the development of colony subpopulations; the main regulation occurs at the level of stabilization of the Gcn4p molecule in the cells of one subpopulation and its proteasomal degradation in the other. This regulation ensures specific spatiotemporal activity of Gcn4p in the colony. Our work highlights differences in regulatory networks in unorganized populations and organized structures of yeast, which in many respects resemble multicellular organisms.
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Affiliation(s)
- Libuše Váchová
- Institute of Microbiology of the Czech Academy of Sciences, BIOCEV, Prague, Czech Republic
| | - Vítězslav Plocek
- Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Jana Maršíková
- Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Stanislava Rešetárová
- Institute of Microbiology of the Czech Academy of Sciences, BIOCEV, Prague, Czech Republic
| | | | - Zdena Palková
- Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
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8
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Ide NA, Gentry RC, Rudbach MA, Yoo K, Velez PK, Comunale VM, Hartwick EW, Kinz-Thompson CD, Gonzalez RL, Aitken CE. A dynamic compositional equilibrium governs mRNA recognition by eIF3. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.581977. [PMID: 38712078 PMCID: PMC11071631 DOI: 10.1101/2024.04.25.581977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Eukaryotic translation initiation factor (eIF) 3 is a multi-subunit protein complex that binds both ribosomes and messenger RNAs (mRNAs) in order to drive a diverse set of mechanistic steps during translation. Despite its importance, a unifying framework explaining how eIF3 performs these numerous activities is lacking. Using single-molecule light scattering microscopy, we demonstrate that Saccharomyces cerevisiae eIF3 is an equilibrium mixture of the full complex, subcomplexes, and subunits. By extending our microscopy approach to an in vitro reconstituted eIF3 and complementing it with biochemical assays, we define the subspecies comprising this equilibrium and show that, rather than being driven by the full complex, mRNA binding by eIF3 is instead driven by the eIF3a subunit within eIF3a-containing subcomplexes. Our findings provide a mechanistic model for the role of eIF3 in the mRNA recruitment step of translation initiation and establish a mechanistic framework for explaining and investigating the other activities of eIF3.
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9
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Magg V, Manetto A, Kopp K, Wu CC, Naghizadeh M, Lindner D, Eke L, Welsch J, Kallenberger SM, Schott J, Haucke V, Locker N, Stoecklin G, Ruggieri A. Turnover of PPP1R15A mRNA encoding GADD34 controls responsiveness and adaptation to cellular stress. Cell Rep 2024; 43:114069. [PMID: 38602876 DOI: 10.1016/j.celrep.2024.114069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 01/25/2024] [Accepted: 03/21/2024] [Indexed: 04/13/2024] Open
Abstract
The integrated stress response (ISR) is a key cellular signaling pathway activated by environmental alterations that represses protein synthesis to restore homeostasis. To prevent sustained damage, the ISR is counteracted by the upregulation of growth arrest and DNA damage-inducible 34 (GADD34), a stress-induced regulatory subunit of protein phosphatase 1 that mediates translation reactivation and stress recovery. Here, we uncover a novel ISR regulatory mechanism that post-transcriptionally controls the stability of PPP1R15A mRNA encoding GADD34. We establish that the 3' untranslated region of PPP1R15A mRNA contains an active AU-rich element (ARE) recognized by proteins of the ZFP36 family, promoting its rapid decay under normal conditions and stabilization for efficient expression of GADD34 in response to stress. We identify the tight temporal control of PPP1R15A mRNA turnover as a component of the transient ISR memory, which sets the threshold for cellular responsiveness and mediates adaptation to repeated stress conditions.
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Affiliation(s)
- Vera Magg
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Alessandro Manetto
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Katja Kopp
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Chia Ching Wu
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Mohsen Naghizadeh
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany
| | - Doris Lindner
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany
| | - Lucy Eke
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Julia Welsch
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Stefan M Kallenberger
- Digital Health Center, Berlin Institute of Health (BIH) and Charité, 10178 Berlin, Germany; Medical Oncology, National Center for Tumor Diseases, Heidelberg University, 69120 Heidelberg, Germany
| | - Johanna Schott
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany; Freie Universität Berlin, Faculty of Biology, Chemistry, and Pharmacy, 14195 Berlin, Germany
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK; The Pirbright Institute, GU24 0NF Pirbright, UK
| | - Georg Stoecklin
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany; Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
| | - Alessia Ruggieri
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany.
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10
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Poonia P, Valabhoju V, Li T, Iben J, Niu X, Lin Z, Hinnebusch AG. Yeast poly(A)-binding protein (Pab1) controls translation initiation in vivo primarily by blocking mRNA decapping and decay. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.19.590253. [PMID: 38903079 PMCID: PMC11188147 DOI: 10.1101/2024.04.19.590253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Poly(A)-binding protein (Pab1 in yeast) is involved in mRNA decay and translation initiation, but its molecular functions are incompletely understood. We found that auxin-induced degradation of Pab1 reduced bulk mRNA and polysome abundance in a manner suppressed by deleting the catalytic subunit of decapping enzyme (dcp2Δ), demonstrating that enhanced decapping/degradation is the major driver of reduced mRNA abundance and protein synthesis at limiting Pab1 levels. An increased median poly(A) tail length conferred by Pab1 depletion was also nullified by dcp2Δ, suggesting that mRNA isoforms with shorter tails are preferentially decapped/degraded at limiting Pab1. In contrast to findings on mammalian cells, the translational efficiencies (TEs) of many mRNAs were altered by Pab1 depletion; however, these changes were broadly diminished by dcp2∆, suggesting that reduced mRNA abundance is a major driver of translational reprogramming at limiting Pab1. Thus, assembly of the closed-loop mRNP via PABP-eIF4G interaction appears to be dispensable for normal translation of most yeast mRNAs in vivo. Interestingly, histone mRNAs and proteins are preferentially diminished on Pab1 depletion dependent on Dcp2, accompanied by activation of internal cryptic promoters in the manner expected for reduced nucleosome occupancies, revealing a new layer of post-transcriptional control of histone gene expression.
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Affiliation(s)
- Poonam Poonia
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Vishalini Valabhoju
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Tianwei Li
- Department of Biology, Saint Louis University, St. Louis, MO
| | - James Iben
- Department of Biology, Saint Louis University, St. Louis, MO
| | - Xiao Niu
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
- Department of Biology, Saint Louis University, St. Louis, MO
| | - Zhenguo Lin
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
- Department of Biology, Saint Louis University, St. Louis, MO
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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11
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González-Sánchez AM, Castellanos-Silva EA, Díaz-Figueroa G, Cate JHD. JUN mRNA translation regulation is mediated by multiple 5' UTR and start codon features. PLoS One 2024; 19:e0299779. [PMID: 38483896 PMCID: PMC10939236 DOI: 10.1371/journal.pone.0299779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/14/2024] [Indexed: 03/17/2024] Open
Abstract
Regulation of mRNA translation by eukaryotic initiation factors (eIFs) is crucial for cell survival. In humans, eIF3 stimulates translation of the JUN mRNA which encodes the transcription factor JUN, an oncogenic transcription factor involved in cell cycle progression, apoptosis, and cell proliferation. Previous studies revealed that eIF3 activates translation of the JUN mRNA by interacting with a stem loop in the 5' untranslated region (5' UTR) and with the 5' -7-methylguanosine cap structure. In addition to its interaction site with eIF3, the JUN 5' UTR is nearly one kilobase in length, and has a high degree of secondary structure, high GC content, and an upstream start codon (uAUG). This motivated us to explore the complexity of JUN mRNA translation regulation in human cells. Here we find that JUN translation is regulated in a sequence and structure-dependent manner in regions adjacent to the eIF3-interacting site in the JUN 5' UTR. Furthermore, we identify contributions of an additional initiation factor, eIF4A, in JUN regulation. We show that enhancing the interaction of eIF4A with JUN by using the compound Rocaglamide A (RocA) represses JUN translation. We also find that both the upstream AUG (uAUG) and the main AUG (mAUG) contribute to JUN translation and that they are conserved throughout vertebrates. Our results reveal additional layers of regulation for JUN translation and show the potential of JUN as a model transcript for understanding multiple interacting modes of translation regulation.
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Affiliation(s)
- Angélica M. González-Sánchez
- Comparative Biochemistry Graduate Program, University of California, Berkeley, Berkeley, CA, United States of America
| | - Eimy A. Castellanos-Silva
- Department of Biochemistry and Molecular Biology, University of California, Davis, Davis, CA, United States of America
| | - Gabriela Díaz-Figueroa
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States of America
| | - Jamie H. D. Cate
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States of America
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12
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Gotsmann VL, Ting MKY, Haase N, Rudorf S, Zoschke R, Willmund F. Utilizing high-resolution ribosome profiling for the global investigation of gene expression in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:1614-1634. [PMID: 38047591 DOI: 10.1111/tpj.16577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/05/2023]
Abstract
Ribosome profiling (Ribo-seq) is a powerful method for the deep analysis of translation mechanisms and regulatory circuits during gene expression. Extraction and sequencing of ribosome-protected fragments (RPFs) and parallel RNA-seq yields genome-wide insight into translational dynamics and post-transcriptional control of gene expression. Here, we provide details on the Ribo-seq method and the subsequent analysis with the unicellular model alga Chlamydomonas reinhardtii (Chlamydomonas) for generating high-resolution data covering more than 10 000 different transcripts. Detailed analysis of the ribosomal offsets on transcripts uncovers presumable transition states during translocation of elongating ribosomes within the 5' and 3' sections of transcripts and characteristics of eukaryotic translation termination, which are fundamentally distinct for chloroplast translation. In chloroplasts, a heterogeneous RPF size distribution along the coding sequence indicates specific regulatory phases during protein synthesis. For example, local accumulation of small RPFs correlates with local slowdown of psbA translation, possibly uncovering an uncharacterized regulatory step during PsbA/D1 synthesis. Further analyses of RPF distribution along specific cytosolic transcripts revealed characteristic patterns of translation elongation exemplified for the major light-harvesting complex proteins, LHCs. By providing high-quality datasets for all subcellular genomes and attaching our data to the Chlamydomonas reference genome, we aim to make ribosome profiles easily accessible for the broad research community. The data can be browsed without advanced bioinformatic background knowledge for translation output levels of specific genes and their splice variants and for monitoring genome annotation.
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Affiliation(s)
- Vincent Leon Gotsmann
- Molecular Genetics of Eukaryotes, RPTU Kaiserslautern-Landau, Paul-Ehrlich-Str. 23, 67663, Kaiserslautern, Germany
| | - Michael Kien Yin Ting
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Nadin Haase
- Institute of Cell Biology and Biophysics, Leibniz University Hanover, Herrenhäuser-Str. 2, 30419, Hanover, Germany
| | - Sophia Rudorf
- Institute of Cell Biology and Biophysics, Leibniz University Hanover, Herrenhäuser-Str. 2, 30419, Hanover, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, RPTU Kaiserslautern-Landau, Paul-Ehrlich-Str. 23, 67663, Kaiserslautern, Germany
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13
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Mao Y, Qian SB. Making sense of mRNA translational "noise". Semin Cell Dev Biol 2024; 154:114-122. [PMID: 36925447 PMCID: PMC10500040 DOI: 10.1016/j.semcdb.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 03/15/2023]
Abstract
The importance of translation fidelity has been apparent since the discovery of genetic code. It is commonly believed that translation deviating from the main coding region is to be avoided at all times inside cells. However, ribosome profiling and mass spectrometry have revealed pervasive noncanonical translation. Both the scope and origin of translational "noise" are just beginning to be appreciated. Although largely overlooked, those translational "noises" are associated with a wide range of cellular functions, such as producing unannotated protein products. Furthermore, the dynamic nature of translational "noise" is responsive to stress conditions, highlighting the beneficial effect of translational "noise" in stress adaptation. Mechanistic investigation of translational "noise" will provide better insight into the mechanisms of translational regulation. Ultimately, they are not "noise" at all but represent a signature of cellular activities under pathophysiological conditions. Deciphering translational "noise" holds the therapeutic and diagnostic potential in a wide spectrum of human diseases.
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Affiliation(s)
- Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
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14
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Schieferecke AJ, Lee H, Chen A, Kilaru V, Krish Williams J, Schaffer DV. Evolving membrane-associated accessory protein variants for improved adeno-associated virus production. Mol Ther 2024; 32:340-351. [PMID: 38115579 PMCID: PMC10861973 DOI: 10.1016/j.ymthe.2023.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/14/2023] [Accepted: 12/14/2023] [Indexed: 12/21/2023] Open
Abstract
Manufacturing sufficient adeno-associated virus (AAV) to meet current and projected clinical needs is a significant hurdle to the growing gene therapy industry. The recently discovered membrane-associated accessory protein (MAAP) is encoded by an alternative open reading frame in the AAV cap gene that is found in all presently reported natural serotypes. Recent evidence has emerged supporting a functional role of MAAP in AAV egress, although the underlying mechanisms of MAAP function remain unknown. Here, we show that inactivation of MAAP from AAV2 by a single point mutation that is silent in the VP1 open reading frame (ORF) (AAV2-ΔMAAP) decreased exosome-associated and secreted vector genome production. We hypothesized that novel MAAP variants could be evolved to increase AAV production and thus subjected a library encoding over 1 × 106 MAAP protein variants to five rounds of packaging selection into the AAV2-ΔMAAP capsid. Between each successive packaging round, we observed a progressive increase in both overall titer and ratio of secreted vector genomes conferred by the bulk-selected MAAP library population. Next-generation sequencing uncovered enriched mutational features, and a resulting selected MAAP variant containing missense mutations and a frameshifted C-terminal domain increased overall GFP transgene packaging in AAV2, AAV6, and AAV9 capsids.
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Affiliation(s)
- Adam J Schieferecke
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Hyuncheol Lee
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Aleysha Chen
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Vindhya Kilaru
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Justin Krish Williams
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - David V Schaffer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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15
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Powers EN, Kuwayama N, Sousa C, Reynaud K, Jovanovic M, Ingolia NT, Brar GA. Dbp1 is a low performance paralog of RNA helicase Ded1 that drives impaired translation and heat stress response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575095. [PMID: 38260653 PMCID: PMC10802583 DOI: 10.1101/2024.01.12.575095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Ded1 and Dbp1 are paralogous conserved RNA helicases that enable translation initiation in yeast. Ded1 has been heavily studied but the role of Dbp1 is poorly understood. We find that the expression of these two helicases is controlled in an inverse and condition-specific manner. In meiosis and other long-term starvation states, Dbp1 expression is upregulated and Ded1 is downregulated, whereas in mitotic cells, Dbp1 expression is extremely low. Inserting the DBP1 ORF in place of the DED1 ORF cannot replace the function of Ded1 in supporting translation, partly due to inefficient mitotic translation of the DBP1 mRNA, dependent on features of its ORF sequence but independent of codon optimality. Global measurements of translation rates and 5' leader translation, activity of mRNA-tethered helicases, ribosome association, and low temperature growth assays show that-even at matched protein levels-Ded1 is more effective than Dbp1 at activating translation, especially for mRNAs with structured 5' leaders. Ded1 supports halting of translation and cell growth in response to heat stress, but Dbp1 lacks this function, as well. These functional differences in the ability to efficiently mediate translation activation and braking can be ascribed to the divergent, disordered N- and C-terminal regions of these two helicases. Altogether, our data show that Dbp1 is a "low performance" version of Ded1 that cells employ in place of Ded1 under long-term conditions of nutrient deficiency.
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16
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Cottrell KA, Andrews RJ, Bass BL. The competitive landscape of the dsRNA world. Mol Cell 2024; 84:107-119. [PMID: 38118451 PMCID: PMC10843539 DOI: 10.1016/j.molcel.2023.11.033] [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: 10/16/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/22/2023]
Abstract
The ability to sense and respond to infection is essential for life. Viral infection produces double-stranded RNAs (dsRNAs) that are sensed by proteins that recognize the structure of dsRNA. This structure-based recognition of viral dsRNA allows dsRNA sensors to recognize infection by many viruses, but it comes at a cost-the dsRNA sensors cannot always distinguish between "self" and "nonself" dsRNAs. "Self" RNAs often contain dsRNA regions, and not surprisingly, mechanisms have evolved to prevent aberrant activation of dsRNA sensors by "self" RNA. Here, we review current knowledge about the life of endogenous dsRNAs in mammals-the biosynthesis and processing of dsRNAs, the proteins they encounter, and their ultimate degradation. We highlight mechanisms that evolved to prevent aberrant dsRNA sensor activation and the importance of competition in the regulation of dsRNA sensors and other dsRNA-binding proteins.
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Affiliation(s)
- Kyle A Cottrell
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA.
| | - Ryan J Andrews
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
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17
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Truniger V, Pechar GS, Aranda MA. Advances in Understanding the Mechanism of Cap-Independent Cucurbit Aphid-Borne Yellows Virus Protein Synthesis. Int J Mol Sci 2023; 24:17598. [PMID: 38139425 PMCID: PMC10744285 DOI: 10.3390/ijms242417598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Non-canonical translation mechanisms have been described for many viral RNAs. In the case of several plant viruses, their protein synthesis is controlled by RNA elements in their genomic 3'-ends that are able to enhance cap-independent translation (3'-CITE). The proposed general mechanism of 3'-CITEs includes their binding to eukaryotic translation initiation factors (eIFs) that reach the 5'-end and AUG start codon through 5'-3'-UTR-interactions. It was previously shown that cucurbit aphid-borne yellows virus (CABYV) has a 3'-CITE, which varies in sequence and structure depending on the phylogenetic group to which the isolate belongs, possibly as a result of adaptation to the different geographical regions. In this work, the cap-independent translation mechanisms of two CABYV 3'-CITEs belonging to the Mediterranean (CMTE) and Asian (CXTE) groups, respectively, were studied. In vivo cap-independent translation assays show that these 3'-CITEs require the presence of the CABYV short genomic 5'-UTR with at least 40% adenines in cis and an accessible 5'-end for its activity. Additionally, they suggest that the eIF4E-independent CABYV 3'-CITE activities may not require either eIF4A or the eIF4F complex, but may depend on eIF4G and PABP. By pulling down host proteins using RNA baits containing both 5'- and 3'-CABYV-UTRs, 80 RNA binding proteins were identified. These interacted preferentially with either CMTE, CXTE, or both. One of these proteins, specifically interacting with the RNA containing CMTE, was HSP70.2. Preliminary results suggested that HSP70.2 may be involved in CMTE- but not CXTE-mediated cap-independent translation activity.
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Affiliation(s)
- Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Murcia, Spain; (G.S.P.); (M.A.A.)
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18
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Onishi T, Nonaka M, Maruno T, Yamaguchi Y, Fukuhara M, Torisu T, Maeda M, Abbatiello S, Haris A, Richardson K, Giles K, Preece S, Yamano-Adachi N, Omasa T, Uchiyama S. Enhancement of recombinant adeno-associated virus activity by improved stoichiometry and homogeneity of capsid protein assembly. Mol Ther Methods Clin Dev 2023; 31:101142. [PMID: 38027055 PMCID: PMC10663676 DOI: 10.1016/j.omtm.2023.101142] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/21/2023] [Indexed: 12/01/2023]
Abstract
Studies of recombinant adeno-associated virus (rAAV) revealed the mixture of full particles with different densities in rAAV. There are no conclusive results because of the lack of quantitative stoichiometric viral proteins, encapsidated DNA, and particle level analyses. We report the first comprehensive characterization of low- and high-density rAAV serotype 2 particles. Capillary gel electrophoresis showed high-density particles possessing a designed DNA encapsidated in the capsid composed of (VP1 + VP2)/VP3 = 0.27, whereas low-density particles have the same DNA but with a different capsid composition of (VP1 + VP2)/VP3 = 0.31, supported by sedimentation velocity-analytical ultracentrifugation and charge detection-mass spectrometry. In vitro analysis demonstrated that the low-density particles had 8.9% higher transduction efficacy than that of the particles before fractionation. Further, based on our recent findings of VP3 clip, we created rAAV2 single amino acid variants of the transcription start methionine of VP3 (M203V) and VP3 clip (M211V). The rAAV2-M203V variant had homogeneous particles with higher (VP1+VP2)/VP3 values (0.35) and demonstrated 24.7% higher transduction efficacy compared with the wild type. This study successfully provided highly functional rAAV by the extensive fractionation from the mixture of rAAV2 full particles or by the single amino acid replacement.
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Affiliation(s)
- Takayuki Onishi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Michika Nonaka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takahiro Maruno
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- U-Medico Inc, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuki Yamaguchi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mitsuko Fukuhara
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- U-Medico Inc, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tetsuo Torisu
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masaharu Maeda
- Osaka Consolidated Laboratory, Manufacturing Technology Association of Biologics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | | | | | - Keith Richardson
- Waters Corporation (Micromass UK Ltd), Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, UK
| | | | - Steve Preece
- Waters Corporation (Micromass UK Ltd), Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, UK
| | - Noriko Yamano-Adachi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takeshi Omasa
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Susumu Uchiyama
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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19
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Reimão-Pinto MM, Castillo-Hair SM, Seelig G, Schier AF. The regulatory landscape of 5' UTRs in translational control during zebrafish embryogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.23.568470. [PMID: 38045294 PMCID: PMC10690280 DOI: 10.1101/2023.11.23.568470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The 5' UTRs of mRNAs are critical for translation regulation, but their in vivo regulatory features are poorly characterized. Here, we report the regulatory landscape of 5' UTRs during early zebrafish embryogenesis using a massively parallel reporter assay of 18,154 sequences coupled to polysome profiling. We found that the 5' UTR is sufficient to confer temporal dynamics to translation initiation, and identified 86 motifs enriched in 5' UTRs with distinct ribosome recruitment capabilities. A quantitative deep learning model, DaniO5P, revealed a combined role for 5' UTR length, translation initiation site context, upstream AUGs and sequence motifs on in vivo ribosome recruitment. DaniO5P predicts the activities of 5' UTR isoforms and indicates that modulating 5' UTR length and motif grammar contributes to translation initiation dynamics. This study provides a first quantitative model of 5' UTR-based translation regulation in early vertebrate development and lays the foundation for identifying the underlying molecular effectors. Highlights In vivo MPRA systematically interrogates the regulatory potential of endogenous 5' UTRs The 5' UTR alone is sufficient to regulate the dynamics of ribosome recruitment during early embryogenesis The MPRA identifies 5' UTR cis -regulatory motifs for translation initiation control 5' UTR length, upstream AUGs and motif grammar contribute to the differential regulatory capability of 5' UTR switching isoforms.
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20
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González-Sánchez AM, Castellanos-Silva EA, Díaz-Figueroa G, Cate JHD. JUN mRNA Translation Regulation is Mediated by Multiple 5' UTR and Start Codon Features. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567602. [PMID: 38014201 PMCID: PMC10680820 DOI: 10.1101/2023.11.17.567602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Regulation of mRNA translation by eukaryotic initiation factors (eIFs) is crucial for cell survival. In humans, eIF3 stimulates translation of the JUN mRNA which encodes the transcription factor JUN, an oncogenic transcription factor involved in cell cycle progression, apoptosis, and cell proliferation. Previous studies revealed that eIF3 activates translation of the JUN mRNA by interacting with a stem loop in the 5' untranslated region (5' UTR) and with the 5'-7-methylguanosine cap structure. In addition to its interaction site with eIF3, the JUN 5' UTR is nearly one kilobase in length, and has a high degree of secondary structure, high GC content, and an upstream start codon (uAUG). This motivated us to explore the complexity of JUN mRNA translation regulation in human cells. Here we find that JUN translation is regulated in a sequence and structure-dependent manner in regions adjacent to the eIF3-interacting site in the JUN 5' UTR. Furthermore, we identify contributions of an additional initiation factor, eIF4A, in JUN regulation. We show that enhancing the interaction of eIF4A with JUN by using the compound Rocaglamide A (RocA) represses JUN translation. We also find that both the upstream AUG (uAUG) and the main AUG (mAUG) contribute to JUN translation and that they are conserved throughout vertebrates. Our results reveal additional layers of regulation for JUN translation and show the potential of JUN as a model transcript for understanding multiple interacting modes of translation regulation.
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Affiliation(s)
| | - Eimy A Castellanos-Silva
- University of California, Davis, Department of Biochemistry and Molecular Biology, Davis, CA, USA
| | - Gabriela Díaz-Figueroa
- University of California, Berkeley, Department of Molecular and Cell Biology, Berkeley, CA, USA
| | - Jamie H D Cate
- University of California, Berkeley, Department of Molecular and Cell Biology, Berkeley, CA, USA
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21
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Mariner BL, Felker DP, Cantergiani RJ, Peterson J, McCormick MA. Multiomics of GCN4-Dependent Replicative Lifespan Extension Models Reveals Gcn4 as a Regulator of Protein Turnover in Yeast. Int J Mol Sci 2023; 24:16163. [PMID: 38003352 PMCID: PMC10671045 DOI: 10.3390/ijms242216163] [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: 10/03/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
We have shown that multiple tRNA synthetase inhibitors can increase lifespan in both the nematode C. elegans and the budding yeast S. cerevisiae by acting through the conserved transcription factor Gcn4 (yeast)/ATF-4 (worms). To further understand the biology downstream from this conserved transcription factor in the yeast model system, we looked at two different yeast models known to have upregulated Gcn4 and GCN4-dependent increased replicative lifespan. These two models were rpl31aΔ yeast and yeast treated with the tRNA synthetase inhibitor borrelidin. We used both proteomic and RNAseq analysis of a block experimental design that included both of these models to identify GCN4-dependent changes in these two long-lived strains of yeast. Proteomic analysis of these yeast indicate that the long-lived yeast have increased abundances of proteins involved in amino acid biosynthesis. The RNAseq of these same yeast uncovered further regulation of protein degradation, identifying the differential expression of genes associated with autophagy and the ubiquitin-proteasome system (UPS). The data presented here further underscore the important role that GCN4 plays in the maintenance of protein homeostasis, which itself is an important hallmark of aging. In particular, the changes in autophagy and UPS-related gene expression that we have observed could also have wide-ranging implications for the understanding and treatment of diseases of aging that are associated with protein aggregation.
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Affiliation(s)
- Blaise L. Mariner
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA (D.P.F.); (R.J.C.)
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Daniel P. Felker
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA (D.P.F.); (R.J.C.)
| | - Ryla J. Cantergiani
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA (D.P.F.); (R.J.C.)
| | - Jack Peterson
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA (D.P.F.); (R.J.C.)
| | - Mark A. McCormick
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA (D.P.F.); (R.J.C.)
- Autophagy, Inflammation, and Metabolism Center of Biomedical Research Excellence, University of New Mexico, Albuquerque, NM 87131, USA
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22
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Helmold BR, Pauss KE, Ozdinler PH. TDP-43 protein interactome informs about perturbed canonical pathways and may help develop personalized medicine approaches for patients with TDP-43 pathology. Drug Discov Today 2023; 28:103769. [PMID: 37714405 PMCID: PMC10872580 DOI: 10.1016/j.drudis.2023.103769] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/22/2023] [Accepted: 09/08/2023] [Indexed: 09/17/2023]
Abstract
Transactive response DNA binding protein of 43 kDa (TDP-43) pathology is a common proteinopathy observed among a broad spectrum of patients with neurodegenerative disease, regardless of the mutation. This suggests that protein-protein interactions of TDP-43 with other proteins may in part be responsible for the pathology. To gain better insights, we investigated TDP-43-binding proteins in each domain and correlated these interactions with canonical pathways. These investigations revealed key cellular events that are involved and are important at each domain and suggested previously identified compounds to modulate key aspects of these canonical pathways. Our approach proposes that personalized medicine approaches, which focus on perturbed cellular mechanisms would be feasible in the near future.
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Affiliation(s)
- Benjamin R Helmold
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Chicago, IL, 60611, USA
| | - Kate E Pauss
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Chicago, IL, 60611, USA
| | - P Hande Ozdinler
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Chicago, IL, 60611, USA; Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics, Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60611, USA; Mesulam Center for Cognitive Neurology and Alzheimer's Disease, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Feinberg School of Medicine, Les Turner ALS Center at Northwestern University, Chicago, IL 60611, USA.
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23
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Wang YW, McKeon MC, Elmore H, Hess J, Golan J, Gage H, Mao W, Harrow L, Gonçalves SC, Hull CM, Pringle A. Invasive Californian death caps develop mushrooms unisexually and bisexually. Nat Commun 2023; 14:6560. [PMID: 37875491 PMCID: PMC10598064 DOI: 10.1038/s41467-023-42317-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 10/05/2023] [Indexed: 10/26/2023] Open
Abstract
Canonical sexual reproduction among basidiomycete fungi involves the fusion of two haploid individuals of different mating types, resulting in a heterokaryotic mycelial body made up of genetically different nuclei. Using population genomics data and experiments, we discover mushrooms of the invasive and deadly Amanita phalloides can also be homokaryotic; evidence of sexual reproduction by single, unmated individuals. In California, genotypes of homokaryotic mushrooms are also found in heterokaryotic mushrooms, implying nuclei of homokaryotic mycelia are also involved in outcrossing. We find death cap mating is controlled by a single mating type locus, but the development of homokaryotic mushrooms appears to bypass mating type gene control. Ultimately, sporulation is enabled by nuclei able to reproduce alone as well as with others, and nuclei competent for both unisexuality and bisexuality have persisted in invaded habitats for at least 17 but potentially as long as 30 years. The diverse reproductive strategies of invasive death caps are likely facilitating its rapid spread, suggesting a profound similarity between plant, animal and fungal invasions.
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Affiliation(s)
- Yen-Wen Wang
- Department of Botany, University of Wisconsin-Madison, Madison, WI, USA.
| | - Megan C McKeon
- Department of Genetics, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | | | | | - Jacob Golan
- Department of Botany, University of Wisconsin-Madison, Madison, WI, USA
| | - Hunter Gage
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - William Mao
- Department of Botany, University of Wisconsin-Madison, Madison, WI, USA
| | - Lynn Harrow
- Department of Botany, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Susana C Gonçalves
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Christina M Hull
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Anne Pringle
- Department of Botany, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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24
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Perenkov AD, Sergeeva AD, Vedunova MV, Krysko DV. In Vitro Transcribed RNA-Based Platform Vaccines: Past, Present, and Future. Vaccines (Basel) 2023; 11:1600. [PMID: 37897003 PMCID: PMC10610676 DOI: 10.3390/vaccines11101600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 10/07/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
mRNA was discovered in 1961, but it was not used as a vaccine until after three decades. Recently, the development of mRNA vaccine technology gained great impetus from the pursuit of vaccines against COVID-19. To improve the properties of RNA vaccines, and primarily their circulation time, self-amplifying mRNA and trans-amplifying mRNA were developed. A separate branch of mRNA technology is circular RNA vaccines, which were developed with the discovery of the possibility of translation on their protein matrix. Circular RNA has several advantages over mRNA vaccines and is considered a fairly promising platform, as is trans-amplifying mRNA. This review presents an overview of the mRNA platform and a critical discussion of the more modern self-amplifying mRNA, trans-amplifying mRNA, and circular RNA platforms created on its basis. Finally, the main features, advantages, and disadvantages of each of the presented mRNA platforms are discussed. This discussion will facilitate the decision-making process in selecting the most appropriate platform for creating RNA vaccines against cancer or viral diseases.
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Affiliation(s)
- Alexey D Perenkov
- Institute of Biology and Biomedicine, National Research Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
| | - Alena D Sergeeva
- Institute of Biology and Biomedicine, National Research Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
| | - Maria V Vedunova
- Institute of Biology and Biomedicine, National Research Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
| | - Dmitri V Krysko
- Institute of Biology and Biomedicine, National Research Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
- Cell Death Investigation and Therapy (CDIT) Laboratory, Anatomy and Embryology Unit, Department of Human Structure and Repair, Faculty of Medicine and Health Science, Ghent University, 9000 Ghent, Belgium
- Cancer Research Institute Ghent, 9000 Ghent, Belgium
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25
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Parmar BS, Kieswetter A, Geens E, Vandewyer E, Ludwig C, Temmerman L. azyx-1 is a new gene that overlaps with zyxin and affects its translation in C. elegans, impacting muscular integrity and locomotion. PLoS Biol 2023; 21:e3002300. [PMID: 37713439 PMCID: PMC10575671 DOI: 10.1371/journal.pbio.3002300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/13/2023] [Accepted: 08/16/2023] [Indexed: 09/17/2023] Open
Abstract
Overlapping genes are widely prevalent; however, their expression and consequences are poorly understood. Here, we describe and functionally characterize a novel zyx-1 overlapping gene, azyx-1, with distinct regulatory functions in Caenorhabditis elegans. We observed conservation of alternative open reading frames (ORFs) overlapping the 5' region of zyxin family members in several animal species, and find shared sites of azyx-1 and zyxin proteoform expression in C. elegans. In line with a standard ribosome scanning model, our results support cis regulation of zyx-1 long isoform(s) by upstream initiating azyx-1a. Moreover, we report on a rare observation of trans regulation of zyx-1 by azyx-1, with evidence of increased ZYX-1 upon azyx-1 overexpression. Our results suggest a dual role for azyx-1 in influencing zyx-1 proteoform heterogeneity and highlight its impact on C. elegans muscular integrity and locomotion.
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Affiliation(s)
- Bhavesh S. Parmar
- Animal Physiology and Neurobiology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Amanda Kieswetter
- Animal Physiology and Neurobiology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Ellen Geens
- Animal Physiology and Neurobiology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Elke Vandewyer
- Animal Physiology and Neurobiology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technische Universität München, München, Germany
| | - Liesbet Temmerman
- Animal Physiology and Neurobiology, University of Leuven (KU Leuven), Leuven, Belgium
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26
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Yeter-Alat H, Belgareh-Touzé N, Huvelle E, Banroques J, Tanner NK. The DEAD-Box RNA Helicase Ded1 Is Associated with Translating Ribosomes. Genes (Basel) 2023; 14:1566. [PMID: 37628617 PMCID: PMC10454743 DOI: 10.3390/genes14081566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
DEAD-box RNA helicases are ATP-dependent RNA binding proteins and RNA-dependent ATPases that possess weak, nonprocessive unwinding activity in vitro, but they can form long-lived complexes on RNAs when the ATPase activity is inhibited. Ded1 is a yeast DEAD-box protein, the functional ortholog of mammalian DDX3, that is considered important for the scanning efficiency of the 48S pre-initiation complex ribosomes to the AUG start codon. We used a modified PAR-CLIP technique, which we call quicktime PAR-CLIP (qtPAR-CLIP), to crosslink Ded1 to 4-thiouridine-incorporated RNAs in vivo using UV light centered at 365 nm. The irradiation conditions are largely benign to the yeast cells and to Ded1, and we are able to obtain a high efficiency of crosslinking under physiological conditions. We find that Ded1 forms crosslinks on the open reading frames of many different mRNAs, but it forms the most extensive interactions on relatively few mRNAs, and particularly on mRNAs encoding certain ribosomal proteins and translation factors. Under glucose-depletion conditions, the crosslinking pattern shifts to mRNAs encoding metabolic and stress-related proteins, which reflects the altered translation. These data are consistent with Ded1 functioning in the regulation of translation elongation, perhaps by pausing or stabilizing the ribosomes through its ATP-dependent binding.
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Affiliation(s)
- Hilal Yeter-Alat
- Expression Génétique Microbienne, Université de Paris Cité & CNRS, IBPC, 13 Rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (E.H.); (J.B.)
- Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, CNRS UMR8261, EGM, 75005 Paris, France
| | - Naïma Belgareh-Touzé
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, UMR8226 CNRS, Institut de Biologie Physico-Chimique, Sorbonne Université, 13 Rue Pierre et Marie Curie, 75005 Paris, France;
| | - Emmeline Huvelle
- Expression Génétique Microbienne, Université de Paris Cité & CNRS, IBPC, 13 Rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (E.H.); (J.B.)
- Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, CNRS UMR8261, EGM, 75005 Paris, France
| | - Josette Banroques
- Expression Génétique Microbienne, Université de Paris Cité & CNRS, IBPC, 13 Rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (E.H.); (J.B.)
- Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, CNRS UMR8261, EGM, 75005 Paris, France
| | - N. Kyle Tanner
- Expression Génétique Microbienne, Université de Paris Cité & CNRS, IBPC, 13 Rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (E.H.); (J.B.)
- Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, CNRS UMR8261, EGM, 75005 Paris, France
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27
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She R, Luo J, Weissman JS. Translational fidelity screens in mammalian cells reveal eIF3 and eIF4G2 as regulators of start codon selectivity. Nucleic Acids Res 2023; 51:6355-6369. [PMID: 37144468 PMCID: PMC10325891 DOI: 10.1093/nar/gkad329] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 04/13/2023] [Accepted: 05/03/2023] [Indexed: 05/06/2023] Open
Abstract
The translation initiation machinery and the ribosome orchestrate a highly dynamic scanning process to distinguish proper start codons from surrounding nucleotide sequences. Here, we performed genome-wide CRISPRi screens in human K562 cells to systematically identify modulators of the frequency of translation initiation at near-cognate start codons. We observed that depletion of any eIF3 core subunit promoted near-cognate start codon usage, though sensitivity thresholds of each subunit to sgRNA-mediated depletion varied considerably. Double sgRNA depletion experiments suggested that enhanced near-cognate usage in eIF3D depleted cells required canonical eIF4E cap-binding and was not driven by eIF2A or eIF2D-dependent leucine tRNA initiation. We further characterized the effects of eIF3D depletion and found that the N-terminus of eIF3D was strictly required for accurate start codon selection, whereas disruption of the cap-binding properties of eIF3D had no effect. Lastly, depletion of eIF3D activated TNFα signaling via NF-κB and the interferon gamma response. Similar transcriptional profiles were observed upon knockdown of eIF1A and eIF4G2, which also promoted near-cognate start codon usage, suggesting that enhanced near-cognate usage could potentially contribute to NF-κB activation. Our study thus provides new avenues to study the mechanisms and consequences of alternative start codon usage.
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Affiliation(s)
- Richard She
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Jingchuan Luo
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Jonathan S Weissman
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology; Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
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28
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Livingston NM, Kwon J, Valera O, Saba JA, Sinha NK, Reddy P, Nelson B, Wolfe C, Ha T, Green R, Liu J, Wu B. Bursting translation on single mRNAs in live cells. Mol Cell 2023; 83:2276-2289.e11. [PMID: 37329884 PMCID: PMC10330622 DOI: 10.1016/j.molcel.2023.05.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/27/2023] [Accepted: 05/14/2023] [Indexed: 06/19/2023]
Abstract
Stochasticity has emerged as a mechanism of gene regulation. Much of this so-called "noise" has been attributed to bursting transcription. Although bursting transcription has been studied extensively, the role of stochasticity in translation has not been fully investigated due to the lack of enabling imaging technology. In this study, we developed techniques to track single mRNAs and their translation in live cells for hours, allowing the measurement of previously uncharacterized translation dynamics. We applied genetic and pharmacological perturbations to control translation kinetics and found that, like transcription, translation is not a constitutive process but instead cycles between inactive and active states, or "bursts." However, unlike transcription, which is largely frequency-modulated, complex structures in the 5'-untranslated region alter burst amplitudes. Bursting frequency can be controlled through cap-proximal sequences and trans-acting factors such as eIF4F. We coupled single-molecule imaging with stochastic modeling to quantitatively determine the kinetic parameters of translational bursting.
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Affiliation(s)
- Nathan M Livingston
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiwoong Kwon
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Oliver Valera
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - James A Saba
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Niladri K Sinha
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pranav Reddy
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Blake Nelson
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Clara Wolfe
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Jian Liu
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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29
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Liu Y, Yao Z, Lian G, Yang P. Biomolecular phase separation in stress granule assembly and virus infection. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1099-1118. [PMID: 37401177 PMCID: PMC10415189 DOI: 10.3724/abbs.2023117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 05/06/2023] [Indexed: 07/05/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) has emerged as a crucial mechanism for cellular compartmentalization. One prominent example of this is the stress granule. Found in various types of cells, stress granule is a biomolecular condensate formed through phase separation. It comprises numerous RNA and RNA-binding proteins. Over the past decades, substantial knowledge has been gained about the composition and dynamics of stress granules. SGs can regulate various signaling pathways and have been associated with numerous human diseases, such as neurodegenerative diseases, cancer, and infectious diseases. The threat of viral infections continues to loom over society. Both DNA and RNA viruses depend on host cells for replication. Intriguingly, many stages of the viral life cycle are closely tied to RNA metabolism in human cells. The field of biomolecular condensates has rapidly advanced in recent times. In this context, we aim to summarize research on stress granules and their link to viral infections. Notably, stress granules triggered by viral infections behave differently from the canonical stress granules triggered by sodium arsenite (SA) and heat shock. Studying stress granules in the context of viral infections could offer a valuable platform to link viral replication processes and host anti-viral responses. A deeper understanding of these biological processes could pave the way for innovative interventions and treatments for viral infectious diseases. They could potentially bridge the gap between basic biological processes and interactions between viruses and their hosts.
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Affiliation(s)
- Yi Liu
- />Westlake Laboratory of Life Sciences and BiomedicineSchool of Life SciencesWestlake UniversityHangzhou310030China
| | - Zhiying Yao
- />Westlake Laboratory of Life Sciences and BiomedicineSchool of Life SciencesWestlake UniversityHangzhou310030China
| | - Guiwei Lian
- />Westlake Laboratory of Life Sciences and BiomedicineSchool of Life SciencesWestlake UniversityHangzhou310030China
| | - Peiguo Yang
- />Westlake Laboratory of Life Sciences and BiomedicineSchool of Life SciencesWestlake UniversityHangzhou310030China
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30
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Wang YW, McKeon MC, Elmore H, Hess J, Golan J, Gage H, Mao W, Harrow L, Gon ßalves SC, Hull CM, Pringle A. Invasive Californian death caps develop mushrooms unisexually and bisexually. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.525609. [PMID: 36778337 PMCID: PMC9915504 DOI: 10.1101/2023.01.30.525609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Canonical sexual reproduction among basidiomycete fungi involves the fusion of two haploid individuals of different sexes, resulting in a heterokaryotic mycelial body made up of genetically different nuclei 1 . Using population genomics data, we discovered mushrooms of the deadly invasive Amanita phalloides are also homokaryotic, evidence of sexual reproduction by single individuals. In California, genotypes of homokaryotic mushrooms are also found in heterokaryotic mushrooms, implying nuclei of homokaryotic mycelia also promote outcrossing. We discovered death cap mating is controlled by a single mating-type locus ( A. phalloides is bipolar), but the development of homokaryotic mushrooms appears to bypass mating-type gene control. Ultimately, sporulation is enabled by nuclei able to reproduce alone as well as with others, and nuclei competent for both unisexuality and bisexuality have persisted in invaded habitats for at least 17 but potentially as long as 30 years. The diverse reproductive strategies of invasive death caps are likely facilitating its rapid spread, revealing a profound similarity between plant, animal and fungal invasions 2,3 .
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31
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Hall MK, Shajahan A, Burch AP, Hatchett CJ, Azadi P, Schwalbe RA. Limited N-Glycan Processing Impacts Chaperone Expression Patterns, Cell Growth and Cell Invasiveness in Neuroblastoma. BIOLOGY 2023; 12:293. [PMID: 36829569 PMCID: PMC9953357 DOI: 10.3390/biology12020293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
Enhanced N-glycan branching is associated with cancer, but recent investigations supported the involvement of less processed N-glycans. Herein, we investigated how changes in N-glycosylation influence cellular properties in neuroblastoma (NB) using rat N-glycan mutant cell lines, NB_1(-Mgat1), NB_1(-Mgat2) and NB_1(-Mgat3), as well as the parental cell line NB_1. The two earlier mutant cells have compromised N-acetylglucosaminyltransferase-I (GnT-I) and GnT-II activities. Lectin blotting showed that NB_1(-Mgat3) cells had decreased activity of GnT-III compared to NB_1. ESI-MS profiles identified N-glycan structures in NB cells, supporting genetic edits. NB_1(-Mgat1) had the most oligomannose N-glycans and the greatest cell invasiveness, while NB_1(-Mgat2) had the fewest and least cell invasiveness. The proliferation rate of NB_1 was slightly slower than NB_1(-Mgat3), but faster than NB_1(-Mgat1) and NB_1(-Mgat2). Faster proliferation rates were due to the faster progression of those cells through the G1 phase of the cell cycle. Further higher levels of oligomannose with 6-9 Man residues indicated faster proliferating cells. Human NB cells with higher oligomannose N-glycans were more invasive and had slower proliferation rates. Both rat and human NB cells revealed modified levels of ER chaperones. Thus, our results support a role of oligomannose N-glycans in NB progression; furthermore, perturbations in the N-glycosylation pathway can impact chaperone systems.
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Affiliation(s)
- M. Kristen Hall
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University Greenville, 600 Moye Boulevard, Greenville, NC 27834, USA
| | - Asif Shajahan
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Adam P. Burch
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University Greenville, 600 Moye Boulevard, Greenville, NC 27834, USA
| | - Cody J. Hatchett
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University Greenville, 600 Moye Boulevard, Greenville, NC 27834, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Ruth A. Schwalbe
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University Greenville, 600 Moye Boulevard, Greenville, NC 27834, USA
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32
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Nishisaka H, Tomohiro T, Fukao A, Funakami Y, Fujiwara T. Neuronal RNA-Binding Protein HuD Interacts with Translation Initiation Factor eIF3. Biol Pharm Bull 2023; 46:158-162. [PMID: 36724943 DOI: 10.1248/bpb.b22-00478] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Translation initiation is the rate-limiting step of protein synthesis and is the main target of translation regulation. RNA-binding proteins (RBPs) are key mediators of the spatiotemporal control of translation and are critical for cell proliferation, development, and differentiation. We have previously shown that HuD, one of the neuronal RBPs, enhances cap-dependent translation through the direct interaction with eukaryotic initiation factor 4A (eIF4A) and poly(A) tail using a HeLa-derived in vitro translation system. We have also found that translation stimulation of HuD is essential for HuD-induced neurite outgrowth in PC12 cells. However, it remains unclear how HuD is involved in the regulation of translation initiation. Here, we report that HuD binds to eukaryotic initiation factor 3 (eIF3) via the eIF3b subunit, which belongs to the functional core of mammalian eIF3. eIF3 plays an essential role in recruiting the 40S ribosomal subunit onto mRNA in translation initiation. We hypothesize that the interaction between HuD and eIF3 stabilizes the translation initiation complex and increases translation efficiency. We also showed that the linker region of HuD is required for the interaction with eIF3b. Moreover, we found that eIF3b-binding region of HuD is conserved in all Hu proteins (HuB, HuC, HuD, and HuR). These data might also help to explain how Hu proteins stimulate translation in a cap- and poly(A)-dependent way.
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33
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A dynamical stochastic model of yeast translation across the cell cycle. Heliyon 2023; 9:e13101. [PMID: 36793957 PMCID: PMC9922973 DOI: 10.1016/j.heliyon.2023.e13101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 01/04/2023] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Translation is a central step in gene expression, however its quantitative and time-resolved regulation is poorly understood. We developed a discrete, stochastic model for protein translation in S. cerevisiae in a whole-transcriptome, single-cell context. A "base case" scenario representing an average cell highlights translation initiation rates as the main co-translational regulatory parameters. Codon usage bias emerges as a secondary regulatory mechanism through ribosome stalling. Demand for anticodons with low abundancy is shown to cause above-average ribosome dwelling times. Codon usage bias correlates strongly both with protein synthesis rates and elongation rates. Applying the model to a time-resolved transcriptome estimated by combining data from FISH and RNA-Seq experiments, it could be shown that increased total transcript abundance during the cell cycle decreases translation efficiency at single transcript level. Translation efficiency grouped by gene function shows highest values for ribosomal and glycolytic genes. Ribosomal proteins peak in S phase while glycolytic proteins rank highest in later cell cycle phases.
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34
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Takallou S, Puchacz N, Allard D, Said KB, Nokhbeh MR, Samanfar B, Golshani A. IRES-mediated translation in bacteria. Biochem Biophys Res Commun 2023; 641:110-115. [PMID: 36527744 DOI: 10.1016/j.bbrc.2022.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
Despite the similarity in fundamental goals of translation initiation between different domains of life, it is one of the most phylogenetically diverse steps of the central dogma of molecular biology. In a classical view, the translation signals for prokaryotes and eukaryotes are distinct from each other. This idea was challenged by the finding that the Internal Ribosome Entry Site (IRES) belonging to Plautia stali intestine virus (PSIV) could bypass the domain-specific boundaries and effectively initiate translation in E. coli. This finding led us to investigate whether the ability of PSIV IRES to initiate translation in E. coli is specific to this IRES and also to study features that allow this viral IRES to mediate prokaryotic translation initiation. We observed that certain IRESs may also possess the ability to initiate E. coli translation. Our results also indicated that the structural integrity of the PSIV IRES in translation in prokaryotes does not appear to be as critical as it is in eukaryotes. We also demonstrated that two regions of the PSIV IRES with complementarity to 16S ribosomal RNA are important for the ability of this IRES to initiate translation in E. coli.
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Affiliation(s)
- Sarah Takallou
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada; Department of Biology, Carleton University, Ottawa, Ontario, Canada.
| | - Nathalie Puchacz
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada; Department of Biology, Carleton University, Ottawa, Ontario, Canada.
| | - Danielle Allard
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada; Department of Biology, Carleton University, Ottawa, Ontario, Canada.
| | - Kamaledin B Said
- Department of Pathology and Microbiology, College of Medicine, University of Hail, Saudi Arabia.
| | | | - Bahram Samanfar
- Department of Biology, Carleton University, Ottawa, Ontario, Canada; Agriculture and Agri-Food Canada, Ottawa Research and Development Centre (ORDC), Ottawa, Ontario, Canada.
| | - Ashkan Golshani
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada; Department of Biology, Carleton University, Ottawa, Ontario, Canada.
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Fernandez SG, Ferguson L, Ingolia NT. Ribosome rescue factor PELOTA modulates translation start site choice and protein isoform levels of transcription factor C/EBP α. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.16.524343. [PMID: 36711859 PMCID: PMC9882168 DOI: 10.1101/2023.01.16.524343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the hematopoietic transcription factor CCAAT-enhancer binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This alternative initiation depends on sequence features of the CEBPA transcript, including a regulatory upstream open reading frame (uORF), but the molecular basis is not fully understood. Here we identify trans-acting factors that affect C/EBPα isoform choice using a sensitive and quantitative two-color fluorescence reporter coupled with CRISPRi screening. Our screen uncovered a role for the ribosome rescue factor PELOTA (PELO) in promoting expression of the longer C/EBPα isoform, by directly removing inhibitory unrecycled ribosomes and through indirect effects mediated by the mechanistic target of rapamycin (mTOR) kinase. Our work provides further mechanistic insights into coupling between ribosome recycling and translation reinitiation in regulation of a key transcription factor, with implications for normal hematopoiesis and leukemiagenesis.
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Affiliation(s)
| | - Lucas Ferguson
- Department of Molecular and Cell Biology, University of California, Berkeley
| | - Nicholas T. Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley
- Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley
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XPO1-Mediated EIF1AX Cytoplasmic Relocation Promotes Tumor Migration and Invasion in Endometrial Carcinoma. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1361135. [PMID: 36589683 PMCID: PMC9800903 DOI: 10.1155/2022/1361135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/30/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
Dysregulation of eukaryotic translation initiation factor 1A, X-linked (EIF1AX), has been implicated in the pathogenesis of some cancers. However, the role of EIF1AX in endometrial carcinoma (EC) remains unknown. We investigated the EIF1AX expression in EC patients and assessed its tumorigenesis-associated function and nucleocytoplasmic transport mechanism in vitro and in vivo. The results indicated that the cytoplasmic EIF1AX expression showed a gradual increase when going from endometrium normal tissue, simple endometrial hyperplasia, complex endometrial hyperplasia, and endometrial atypical hyperplasia to EC, while vice versa for the nuclear EIF1AX expression. In addition, the cytoplasmic EIF1AX expression was positively correlated with histologic type, high International Federation of Gynecology and Obstetrics (FIGO) grade, advanced FIGO stage, deeper infiltration, high Ki67 index, and shorter recurrence-free survival in EC patients. In vitro, short hairpin RNA-mediated EIF1AX depletion or SV40NLS-mediated EIF1AX import into the nucleus in multiple human EC cells potently suppressed cell migration and invasion, epithelial-mesenchymal transition, and lung metastasis. Moreover, exportin 1 induced the transport of EIF1AX from the nucleus to the cytoplasm that could be inhibited by leptomycin B treatment or the mutation in the EIF1AX location sequence. These results demonstrate that cytoplasmic EIF1AX may play a key role in the incidence and promotion of EC, and thus, targeting EIF1AX or its nucleocytoplasmic transport process may offer an effective new therapeutic approach to EC.
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Li K, Kong J, Zhang S, Zhao T, Qian W. Distance-dependent inhibition of translation initiation by downstream out-of-frame AUGs is consistent with a Brownian ratchet process of ribosome scanning. Genome Biol 2022; 23:254. [PMID: 36510274 PMCID: PMC9743702 DOI: 10.1186/s13059-022-02829-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 12/01/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Eukaryotic ribosomes are widely presumed to scan mRNA for the AUG codon to initiate translation in a strictly 5'-3' movement (i.e., strictly unidirectional scanning model), so that ribosomes initiate translation exclusively at the 5' proximal AUG codon (i.e., the first-AUG rule). RESULTS We generate 13,437 yeast variants, each with an ATG triplet placed downstream (dATGs) of the annotated ATG (aATG) codon of a green fluorescent protein. We find that out-of-frame dATGs can inhibit translation at the aATG, but with diminishing strength over increasing distance between aATG and dATG, undetectable beyond ~17 nt. This phenomenon is best explained by a Brownian ratchet mechanism of ribosome scanning, in which the ribosome uses small-amplitude 5'-3' and 3'-5' oscillations with a net 5'-3' movement to scan the AUG codon, thereby leading to competition for translation initiation between aAUG and a proximal dAUG. This scanning model further predicts that the inhibitory effect induced by an out-of-frame upstream AUG triplet (uAUG) will diminish as uAUG approaches aAUG, which is indeed observed among the 15,586 uATG variants generated in this study. Computational simulations suggest that each triplet is scanned back and forth approximately ten times until the ribosome eventually migrates to downstream regions. Moreover, this scanning process could constrain the evolution of sequences downstream of the aATG to minimize proximal out-of-frame dATG triplets in yeast and humans. CONCLUSIONS Collectively, our findings uncover the basic process by which eukaryotic ribosomes scan for initiation codons, and how this process could shape eukaryotic genome evolution.
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Affiliation(s)
- Ke Li
- grid.418558.50000 0004 0596 2989State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101 China
| | - Jinhui Kong
- grid.418558.50000 0004 0596 2989State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Shuo Zhang
- grid.418558.50000 0004 0596 2989State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Tong Zhao
- grid.458488.d0000 0004 0627 1442Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Wenfeng Qian
- grid.418558.50000 0004 0596 2989State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
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Expression of miRNA-Targeted and Not-Targeted Reporter Genes Shows Mutual Influence and Intercellular Specificity. Int J Mol Sci 2022; 23:ijms232315059. [PMID: 36499386 PMCID: PMC9740606 DOI: 10.3390/ijms232315059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/04/2022] Open
Abstract
The regulation of translation by RNA-induced silencing complexes (RISCs) composed of Argonaute proteins and micro-RNAs is well established; however, the mechanisms underlying specific cellular responses to miRNAs and how specific complexes arise are not completely clear. To explore these questions, we performed experiments with Renilla and firefly luciferase reporter genes transfected in a psiCHECK-2 plasmid into human HCT116 or Me45 cells, where only the Renilla gene contained sequences targeted by microRNAs (miRNAs) in the 3'UTR. The effects of targeting were miRNA-specific; miRNA-21-5p caused strong inhibition of translation, whereas miRNA-24-3p or Let-7 family caused no change or an increase in reporter Renilla luciferase synthesis. The mRNA-protein complexes formed by transcripts regulated by different miRNAs differed from each other and were different in different cell types, as shown by sucrose gradient centrifugation. Unexpectedly, the presence of miRNA targets on Renilla transcripts also affected the expression of the co-transfected but non-targeted firefly luciferase gene in both cell types. Renilla and firefly transcripts were found in the same sucrose gradient fractions and specific anti-miRNA oligoribonucleotides, which influenced the expression of the Renilla gene, and also influenced that of firefly gene. These results suggest that, in addition to targeted transcripts, miRNAs may also modulate the expression of non-targeted transcripts, and using the latter to normalize the results may cause bias. We discuss some hypothetical mechanisms which could explain the observed miRNA-induced effects.
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Preinitiation Complex Loading onto mRNAs with Long versus Short 5' TLs. Int J Mol Sci 2022; 23:ijms232113369. [PMID: 36362157 PMCID: PMC9658832 DOI: 10.3390/ijms232113369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
The first step in translation initiation consists in the recruitment of the small ribosome onto the mRNA. This preinitiation complex (PIC) loads via interactions with eIF4F that has assembled on the 5' cap. It then scans the 5' TL (transcript leader) to locate a start site. The molecular architecture of the PIC-mRNA complex over the cap is beginning to be resolved. As part of this, we have been examining the role of the 5' TL length. We observed in vivo initiation events on AUG codons positioned within 3 nts of the 5' cap and robust initiation in vitro at start sites immediately downstream of the 5' end. Ribosomal toe-printing confirmed the positioning of these codons within the P site, indicating that the ribosome reads from the +1 position. To explore differences in the eIF4E-5' cap interaction in the context of long versus short TL, we followed the fate of the eIF4E-cap interaction using a novel solid phase in vitro expression assay. We observed that ribosome recruitment onto a short TL disrupts the eIF4E-cap contact releasing all the mRNA from the solid phase, whereas with a long the mRNA distributes between both phases. These results are discussed in the context of current recruitment models.
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40
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Shi JJ, Cao Y, Lang QH, Dong Y, Huang LY, Yang LJ, Li JJ, Zhang XX, Wang DY. The effect of the nucleotides immediately upstream of the AUG start codon on the efficiency of translation initiation in sperm cells. PLANT REPRODUCTION 2022; 35:221-231. [PMID: 35674836 DOI: 10.1007/s00497-022-00442-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
It is widely known that an optimal nucleotide sequence context immediately upstream of the AUG start codon greatly improves the efficiency of translation initiation of mRNA in mammalian and plant somatic cells, which in turn increases protein levels. However, it is still unclear whether a similar regulatory mechanism is also present in highly differentiated cells. Here, we surveyed this issue in Arabidopsis thaliana sperm cells and found that the sequence context-mediated regulation of translation initiation in sperm cells is generally similar to that in somatic cells. A simple motif of four adenine nucleotides at positions - 1 to - 4 greatly improved the efficiency of translation initiation, and when the motif was present there, translation was even initiated at some non-AUG codons in sperm cells. However, unlike that in mammalian cells, a mainly effective nucleotide site to regulate the efficiency of translation initiation was not present at positions - 1 to - 4 in sperm cells. Meanwhile, different from somatic cells, sperm cells did not use eukaryotic translation initiation factor 1 to regulate the efficiency in a poor context consisting of the lowest frequency nucleotides. All these results contribute to our understanding of the cytoplasmic event of translation initiation in highly differentiated sperm cells.
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Affiliation(s)
- Jiao-Jiao Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Yuan Cao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Qiu-Hua Lang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Yao Dong
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Liu-Yuan Huang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Liu-Jie Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Jing-Jing Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Xue-Xin Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China
| | - Dan-Yang Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, 710069, China.
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41
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Internal Ribosome Entry Site (IRES)-Mediated Translation and Its Potential for Novel mRNA-Based Therapy Development. Biomedicines 2022; 10:biomedicines10081865. [PMID: 36009412 PMCID: PMC9405587 DOI: 10.3390/biomedicines10081865] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/26/2022] [Accepted: 07/29/2022] [Indexed: 11/17/2022] Open
Abstract
Many conditions can benefit from RNA-based therapies, namely, those targeting internal ribosome entry sites (IRESs) and their regulatory proteins, the IRES trans-acting factors (ITAFs). IRES-mediated translation is an alternative mechanism of translation initiation, known for maintaining protein synthesis when canonical translation is impaired. During a stress response, it contributes to cell reprogramming and adaptation to the new environment. The relationship between IRESs and ITAFs with tumorigenesis and resistance to therapy has been studied in recent years, proposing new therapeutic targets and treatments. In addition, IRES-dependent translation initiation dysregulation is also related to neurological and cardiovascular diseases, muscular atrophies, or other syndromes. The participation of these structures in the development of such pathologies has been studied, yet to a far lesser extent than in cancer. Strategies involving the disruption of IRES–ITAF interactions or the modification of ITAF expression levels may be used with great impact in the development of new therapeutics. In this review, we aim to comprehend the current data on groups of human pathologies associated with IRES and/or ITAF dysregulation and their application in the designing of new therapeutic approaches using them as targets or tools. Thus, we wish to summarise the evidence in the field hoping to open new promising lines of investigation toward personalised treatments.
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42
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Tian Y, Liu Q, Zhou Y, Chen XY, Pan Y, Xu H, Yang Z. Identification of a Novel Heterozygous Mutation in the EIF2B4 Gene Associated With Vanishing White Matter Disease. Front Bioeng Biotechnol 2022; 10:901452. [PMID: 35860328 PMCID: PMC9289103 DOI: 10.3389/fbioe.2022.901452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/23/2022] [Indexed: 12/02/2022] Open
Abstract
Vanishing white matter disease (VWM) is one of the most common childhood inherited leukoencephalopathies with autosomal recessive inheritance. Mutations in five genes, EIF2B1-5, have been identified as the major cause of VWM. In this study, a targeted gene capture sequencing panel comprising 160 known pathogenic genes associated with leukoencephalopathies was performed in a large Han Chinese family affected by adult-onset VWM, and a novel heterozygous missense mutation (c.1337G > A [p. R446H]) in EIF2B4 (NM_001034116.2) was detected. Further functional studies in HEK 293 cells showed dramatically reduced EIF2Bδ protein levels in the mutated group compared with the wild-type group. This study revealed that a heterozygous missense mutation (c.1337G > A [p. R446H]) in EIF2B4 was potentially associated with the adult-onset mild phenotype of VWM. In contrast to previous reports, autosomal dominant inheritance was also observed in adult-onset VWM.
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Affiliation(s)
- Yun Tian
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Qiong Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Yafang Zhou
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xiao-Yu Chen
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Yongcheng Pan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Hongwei Xu
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Zhuanyi Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Zhuanyi Yang,
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43
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Saghaleyni R, Malm M, Moruzzi N, Zrimec J, Razavi R, Wistbacka N, Thorell H, Pintar A, Hober A, Edfors F, Chotteau V, Berggren PO, Grassi L, Zelezniak A, Svensson T, Hatton D, Nielsen J, Robinson JL, Rockberg J. Enhanced metabolism and negative regulation of ER stress support higher erythropoietin production in HEK293 cells. Cell Rep 2022; 39:110936. [PMID: 35705050 DOI: 10.1016/j.celrep.2022.110936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/05/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
Recombinant protein production can cause severe stress on cellular metabolism, resulting in limited titer and product quality. To investigate cellular and metabolic characteristics associated with these limitations, we compare HEK293 clones producing either erythropoietin (EPO) (secretory) or GFP (non-secretory) protein at different rates. Transcriptomic and functional analyses indicate significantly higher metabolism and oxidative phosphorylation in EPO producers compared with parental and GFP cells. In addition, ribosomal genes exhibit specific expression patterns depending on the recombinant protein and the production rate. In a clone displaying a dramatically increased EPO secretion, we detect higher gene expression related to negative regulation of endoplasmic reticulum (ER) stress, including upregulation of ATF6B, which aids EPO production in a subset of clones by overexpression or small interfering RNA (siRNA) knockdown. Our results offer potential target pathways and genes for further development of the secretory power in mammalian cell factories.
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Affiliation(s)
- Rasool Saghaleyni
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Magdalena Malm
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Noah Moruzzi
- The Rolf Luft Research Center for Diabetes and Endocrinology, Department of Molecular Medicine and Surgery, Karolinska Institute, 17176 Stockholm, Sweden
| | - Jan Zrimec
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Ronia Razavi
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Num Wistbacka
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Hannes Thorell
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Anton Pintar
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Andreas Hober
- Science for Life Laboratory, KTH - Royal Institute of Technology, 171 65 Solna, Sweden
| | - Fredrik Edfors
- Science for Life Laboratory, KTH - Royal Institute of Technology, 171 65 Solna, Sweden
| | - Veronique Chotteau
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Industrial Biotechnology, 106 91 Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Department of Molecular Medicine and Surgery, Karolinska Institute, 17176 Stockholm, Sweden
| | - Luigi Grassi
- Cell Culture & Fermentation Sciences, BioPharmaceutical Development, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Aleksej Zelezniak
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Thomas Svensson
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Department of Biology and Biological Engineering, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Chalmers University of Technology, Kemivägen 10, 41258 Gothenburg, Sweden
| | - Diane Hatton
- Cell Culture & Fermentation Sciences, BioPharmaceutical Development, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Jonathan L Robinson
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Department of Biology and Biological Engineering, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Chalmers University of Technology, Kemivägen 10, 41258 Gothenburg, Sweden.
| | - Johan Rockberg
- KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Department of Protein Science, 106 91 Stockholm, Sweden.
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Beyond Moco Biosynthesis-Moonlighting Roles of MoaE and MOCS2. Molecules 2022; 27:molecules27123733. [PMID: 35744859 PMCID: PMC9228816 DOI: 10.3390/molecules27123733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/02/2022] [Accepted: 06/08/2022] [Indexed: 11/17/2022] Open
Abstract
Molybdenum cofactor (Moco) biosynthesis requires iron, copper, and ATP. The Moco-containing enzyme sulfite oxidase catalyzes terminal oxidation in oxidative cysteine catabolism, and another Moco-containing enzyme, xanthine dehydrogenase, functions in purine catabolism. Thus, molybdenum enzymes participate in metabolic pathways that are essential for cellular detoxication and energy dynamics. Studies of the Moco biosynthetic enzymes MoaE (in the Ada2a-containing (ATAC) histone acetyltransferase complex) and MOCS2 have revealed that Moco biosynthesis and molybdenum enzymes align to regulate signaling and metabolism via control of transcription and translation. Disruption of these functions is involved in the onset of dementia and neurodegenerative disease. This review provides an overview of the roles of MoaE and MOCS2 in normal cellular processes and neurodegenerative disease, as well as directions for future research.
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45
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Westhof E, Thornlow B, Chan PP, Lowe TM. Eukaryotic tRNA sequences present conserved and amino acid-specific structural signatures. Nucleic Acids Res 2022; 50:4100-4112. [PMID: 35380696 PMCID: PMC9023262 DOI: 10.1093/nar/gkac222] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/16/2022] [Accepted: 03/22/2022] [Indexed: 11/18/2022] Open
Abstract
Metazoan organisms have many tRNA genes responsible for decoding amino acids. The set of all tRNA genes can be grouped in sets of common amino acids and isoacceptor tRNAs that are aminoacylated by corresponding aminoacyl-tRNA synthetases. Analysis of tRNA alignments shows that, despite the high number of tRNA genes, specific tRNA sequence motifs are highly conserved across multicellular eukaryotes. The conservation often extends throughout the isoacceptors and isodecoders with, in some cases, two sets of conserved isodecoders. This study is focused on non-Watson–Crick base pairs in the helical stems, especially GoU pairs. Each of the four helical stems may contain one or more conserved GoU pairs. Some are amino acid specific and could represent identity elements for the cognate aminoacyl tRNA synthetases. Other GoU pairs are found in more than a single amino acid and could be critical for native folding of the tRNAs. Interestingly, some GoU pairs are anticodon-specific, and others are found in phylogenetically-specific clades. Although the distribution of conservation likely reflects a balance between accommodating isotype-specific functions as well as those shared by all tRNAs essential for ribosomal translation, such conservations may indicate the existence of specialized tRNAs for specific translation targets, cellular conditions, or alternative functions.
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Affiliation(s)
- Eric Westhof
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR 9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France
| | - Bryan Thornlow
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA.,UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Patricia P Chan
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA.,UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Todd M Lowe
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA.,UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, CA 95064, USA
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46
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Ram AK, Mallik M, Reddy RR, Suryawanshi AR, Alone PV. Altered proteome in translation initiation fidelity defective eIF5 G31R mutant causes oxidative stress and DNA damage. Sci Rep 2022; 12:5033. [PMID: 35322093 PMCID: PMC8943034 DOI: 10.1038/s41598-022-08857-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/07/2022] [Indexed: 12/15/2022] Open
Abstract
The recognition of the AUG start codon and selection of an open reading frame (ORF) is fundamental to protein biosynthesis. Defect in the fidelity of start codon selection adversely affect proteome and have a pleiotropic effect on cellular function. Using proteomic techniques, we identified differential protein abundance in the translation initiation fidelity defective eIF5G31R mutant that initiates translation using UUG codon in addition to the AUG start codon. Consistently, the eIF5G31R mutant altered proteome involved in protein catabolism, nucleotide biosynthesis, lipid biosynthesis, carbohydrate metabolism, oxidation–reduction pathway, autophagy and re-programs the cellular pathways. The utilization of the upstream UUG codons by the eIF5G31R mutation caused downregulation of uridylate kinase expression, sensitivity to hydroxyurea, and DNA damage. The eIF5G31R mutant cells showed lower glutathione levels, high ROS activity, and sensitivity to H2O2.
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Affiliation(s)
- Anup Kumar Ram
- School of Biological Sciences, National Institute of Science Education and Research Bhubaneswar, P.O Jatni, Khurda, 752050, India.,Homi Bhabha National Institute (HBNI), Anushakti Nagar, Mumbai, 400094, India
| | - Monalisha Mallik
- School of Biological Sciences, National Institute of Science Education and Research Bhubaneswar, P.O Jatni, Khurda, 752050, India.,Homi Bhabha National Institute (HBNI), Anushakti Nagar, Mumbai, 400094, India
| | - R Rajendra Reddy
- Clinical Proteomics, DBT-Institute of Life Sciences, Bhubaneswar, Odisha, 751023, India
| | | | - Pankaj V Alone
- School of Biological Sciences, National Institute of Science Education and Research Bhubaneswar, P.O Jatni, Khurda, 752050, India. .,Homi Bhabha National Institute (HBNI), Anushakti Nagar, Mumbai, 400094, India.
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47
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Gilbert A, Saveanu C. Unusual SMG suspects recruit degradation enzymes in nonsense-mediated mRNA decay. Bioessays 2022; 44:e2100296. [PMID: 35266563 DOI: 10.1002/bies.202100296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/27/2022] [Accepted: 03/02/2022] [Indexed: 11/09/2022]
Abstract
Degradation of eukaryotic RNAs that contain premature termination codons (PTC) during nonsense-mediated mRNA decay (NMD) is initiated by RNA decapping or endonucleolytic cleavage driven by conserved factors. Models for NMD mechanisms, including recognition of PTCs or the timing and role of protein phosphorylation for RNA degradation are challenged by new results. For example, the depletion of the SMG5/7 heterodimer, thought to activate RNA degradation by decapping, leads to a phenotype showing a defect of endonucleolytic activity of NMD complexes. This phenotype is not correlated to a decreased binding of the endonuclease SMG6 with the core NMD factor UPF1, suggesting that it is the result of an imbalance between active (e.g., in polysomes) and inactive (e.g., in RNA-protein condensates) states of NMD complexes. Such imbalance between multiple complexes is not restricted to NMD and should be taken into account when establishing causal links between gene function perturbation and observed phenotypes.
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Affiliation(s)
- Agathe Gilbert
- Institut Pasteur, Sorbonne Université, CNRS UMR-3525, Paris, F-75015, France
| | - Cosmin Saveanu
- Institut Pasteur, Sorbonne Université, CNRS UMR-3525, Paris, F-75015, France
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48
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de Melo Madureira ÁN, de Oliveira JRS, de Menezes Lima VL. The Role of IL-6 Released During Exercise to Insulin Sensitivity and Muscle Hypertrophy. Mini Rev Med Chem 2022; 22:2419-2428. [PMID: 35264090 DOI: 10.2174/1389557522666220309161245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/25/2021] [Accepted: 01/27/2022] [Indexed: 11/22/2022]
Abstract
Interleukin-6 (IL-6) influences both inflammatory response and anti-inflammatory processes. This cytokine can be released by the exercising skeletal muscle, which characterizes it as a myokine. Unlike what is observed in inflammation, IL-6 produced by skeletal muscle is not preceded by the release of other pro-inflammatory cytokines, but is seems to be dependent on the lactate produced during exercise, thus causing different effects from those of seen in inflammatory state. After binding to its receptor, myokine IL-6 activates the PI3K-Akt pathway. One consequence of this upregulation is the potentiation of insulin signaling, which enhances insulin sensitivity. IL-6 increases GLUT-4 vesicle mobilization to muscle cell periphery, increasing the glucose transport into the cell, and also glycogen synthesis. Muscle glycogen provides energy for the ATP resynthesis, and regulates Ca2+ release by the sarcoplasmic reticulum, influencing muscle contraction, and, hence, muscle function by multiple pathways. Another implication for the upregulation of PI3K-Akt pathway is the activation of mTORC1, which regulates mRNA translational efficiency by regulating translation machinery, and translational capacity by inducing ribosomal biogenesis. Thus, IL-6 may contribute for skeletal muscle hypertrophy and function by increasing contractile protein synthesis.
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Affiliation(s)
- Álvaro Nóbrega de Melo Madureira
- Laboratory of Lipids and Application of Biomolecules to Prevalent and Neglected Diseases (LAB-DPN), Department of Biochemistry, Federal University of Pernambuco (UFPE)
| | - João Ricardhis Saturnino de Oliveira
- Laboratory of Lipids and Application of Biomolecules to Prevalent and Neglected Diseases (LAB-DPN), Department of Biochemistry, Federal University of Pernambuco (UFPE)
| | - Vera Lúcia de Menezes Lima
- Laboratory of Lipids and Application of Biomolecules to Prevalent and Neglected Diseases (LAB-DPN), Department of Biochemistry, Federal University of Pernambuco (UFPE)
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49
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Evolutionarily conserved inhibitory uORFs sensitize Hox mRNA translation to start codon selection stringency. Proc Natl Acad Sci U S A 2022; 119:2117226119. [PMID: 35217614 PMCID: PMC8892498 DOI: 10.1073/pnas.2117226119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2022] [Indexed: 01/15/2023] Open
Abstract
Translation start site selection in eukaryotes is influenced by context nucleotides flanking the AUG codon and by levels of the eukaryotic translation initiation factors eIF1 and eIF5. In a search of mammalian genes, we identified five homeobox (Hox) gene paralogs initiated by AUG codons in conserved suboptimal context as well as 13 Hox genes that contain evolutionarily conserved upstream open reading frames (uORFs) that initiate at AUG codons in poor sequence context. An analysis of published cap analysis of gene expression sequencing (CAGE-seq) data and generated CAGE-seq data for messenger RNAs (mRNAs) from mouse somites revealed that the 5' leaders of Hox mRNAs of interest contain conserved uORFs, are generally much shorter than reported, and lack previously proposed internal ribosome entry site elements. We show that the conserved uORFs inhibit Hox reporter expression and that altering the stringency of start codon selection by overexpressing eIF1 or eIF5 modulates the expression of Hox reporters. We also show that modifying ribosome homeostasis by depleting a large ribosomal subunit protein or treating cells with sublethal concentrations of puromycin leads to lower stringency of start codon selection. Thus, altering global translation can confer gene-specific effects through altered start codon selection stringency.
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50
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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.
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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; ;
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