1
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Torices L, Nunes-Xavier CE, Pulido R. Potentiation by Protein Synthesis Inducers of Translational Readthrough of Pathogenic Premature Termination Codons in PTEN Isoforms. Cancers (Basel) 2024; 16:2836. [PMID: 39199607 PMCID: PMC11352852 DOI: 10.3390/cancers16162836] [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: 06/22/2024] [Revised: 08/05/2024] [Accepted: 08/12/2024] [Indexed: 09/01/2024] Open
Abstract
The PTEN tumor suppressor is frequently targeted in tumors and patients with PTEN hamartoma tumor syndrome (PHTS) through nonsense mutations generating premature termination codons (PTC) that may cause the translation of truncated non-functional PTEN proteins. We have previously described a global analysis of the readthrough reconstitution of the protein translation and function of the human canonical PTEN isoform by aminoglycosides. Here, we report the efficient functional readthrough reconstitution of the PTEN translational isoform PTEN-L, which displays a minimal number of PTC in its specific N-terminal extension in association with disease. We illustrate the importance of the specific PTC and its nucleotide proximal sequence for optimal readthrough and show that the more frequent human PTEN PTC variants and their mouse PTEN PTC equivalents display similar patterns of readthrough efficiency. The heterogeneous readthrough response of the different PTEN PTC variants was independent of the length of the PTEN protein being reconstituted, and we found a correlation between the amount of PTEN protein being synthesized and the PTEN readthrough efficiency. Furthermore, combination of aminoglycosides and protein synthesis inducers increased the readthrough response of specific PTEN PTC. Our results provide insights with which to improve the functional reconstitution of human-disease-related PTC pathogenic variants from PTEN isoforms by increasing protein synthesis coupled to translational readthrough.
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Affiliation(s)
- Leire Torices
- Biobizkaia Health Research Institute, 48903 Barakaldo, Spain; (L.T.); (C.E.N.-X.)
| | - Caroline E. Nunes-Xavier
- Biobizkaia Health Research Institute, 48903 Barakaldo, Spain; (L.T.); (C.E.N.-X.)
- Institute for Cancer Research, Oslo University Hospital, 0424 Oslo, Norway
- Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, ISCIII, 28029 Madrid, Spain
| | - Rafael Pulido
- Biobizkaia Health Research Institute, 48903 Barakaldo, Spain; (L.T.); (C.E.N.-X.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, ISCIII, 28029 Madrid, Spain
- Ikerbasque, The Basque Foundation for Science, 48009 Bilbao, Spain
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2
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Tierney JAS, Świrski M, Tjeldnes H, Mudge JM, Kufel J, Whiffin N, Valen E, Baranov PV. Ribosome decision graphs for the representation of eukaryotic RNA translation complexity. Genome Res 2024; 34:530-538. [PMID: 38719470 PMCID: PMC11146595 DOI: 10.1101/gr.278810.123] [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: 12/04/2023] [Accepted: 04/01/2024] [Indexed: 05/21/2024]
Abstract
The application of ribosome profiling has revealed an unexpected abundance of translation in addition to that responsible for the synthesis of previously annotated protein-coding regions. Multiple short sequences have been found to be translated within single RNA molecules, within both annotated protein-coding and noncoding regions. The biological significance of this translation is a matter of intensive investigation. However, current schematic or annotation-based representations of mRNA translation generally do not account for the apparent multitude of translated regions within the same molecules. They also do not take into account the stochasticity of the process that allows alternative translations of the same RNA molecules by different ribosomes. There is a need for formal representations of mRNA complexity that would enable the analysis of quantitative information on translation and more accurate models for predicting the phenotypic effects of genetic variants affecting translation. To address this, we developed a conceptually novel abstraction that we term ribosome decision graphs (RDGs). RDGs represent translation as multiple ribosome paths through untranslated and translated mRNA segments. We termed the latter "translons." Nondeterministic events, such as initiation, reinitiation, selenocysteine insertion, or ribosomal frameshifting, are then represented as branching points. This representation allows for an adequate representation of eukaryotic translation complexity and focuses on locations critical for translation regulation. We show how RDGs can be used for depicting translated regions and for analyzing genetic variation and quantitative genome-wide data on translation for characterization of regulatory modulators of translation.
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Affiliation(s)
- Jack A S Tierney
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 K8AF, Ireland
- SFI Centre for Research Training in Genomics Data Science, University College Cork, Cork T12 K8AF, Ireland
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Håkon Tjeldnes
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 K8AF, Ireland
- Computational Biology Unit, Department of Informatics, University of Bergen, NO-5020 Bergen, Norway
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton CB10 1SD, Cambridge, United Kingdom
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Nicola Whiffin
- The Big Data Institute and Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Eivind Valen
- Computational Biology Unit, Department of Informatics, University of Bergen, NO-5020 Bergen, Norway
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 K8AF, Ireland;
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3
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Shestakova ED, Tumbinsky RS, Andreev DE, Rozov FN, Shatsky IN, Terenin IM. The Roles of eIF4G2 in Leaky Scanning and Reinitiation on the Human Dual-Coding POLG mRNA. Int J Mol Sci 2023; 24:17149. [PMID: 38138978 PMCID: PMC10742948 DOI: 10.3390/ijms242417149] [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: 11/03/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
Upstream open reading frames (uORFs) are a frequent feature of eukaryotic mRNAs. Upstream ORFs govern main ORF translation in a variety of ways, but, in a nutshell, they either filter out scanning ribosomes or allow downstream translation initiation via leaky scanning or reinitiation. Previous reports concurred that eIF4G2, a long-known but insufficiently studied eIF4G1 homologue, can rescue the downstream translation, but disagreed on whether it is leaky scanning or reinitiation that eIF4G2 promotes. Here, we investigated a unique human mRNA that encodes two highly conserved proteins (POLGARF with unknown function and POLG, the catalytic subunit of the mitochondrial DNA polymerase) in overlapping reading frames downstream of a regulatory uORF. We show that the uORF renders the translation of both POLGARF and POLG mRNAs reliant on eIF4G2. Mechanistically, eIF4G2 enhances both leaky scanning and reinitiation, and it appears that ribosomes can acquire eIF4G2 during the early steps of reinitiation. This emphasizes the role of eIF4G2 as a multifunctional scanning guardian that replaces eIF4G1 to facilitate ribosome movement but not ribosome attachment to an mRNA.
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Affiliation(s)
- Ekaterina D. Shestakova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia (R.S.T.)
| | - Roman S. Tumbinsky
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia (R.S.T.)
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
| | - Dmitri E. Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, 117997 Moscow, Russia
| | - Fedor N. Rozov
- Department of Biochemistry, School of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Ivan N. Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
| | - Ilya M. Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
- Translational Medicine Research Center, Sirius University of Science and Technology, Olimpiyskiy ave. b.1, 354349 Sochi, Russia
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4
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Tierney JAS, Świrski M, Tjeldnes H, Mudge JM, Kufel J, Whiffin N, Valen E, Baranov PV. Ribosome Decision Graphs for the Representation of Eukaryotic RNA Translation Complexity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.10.566564. [PMID: 37986835 PMCID: PMC10659439 DOI: 10.1101/2023.11.10.566564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The application of ribosome profiling has revealed an unexpected abundance of translation in addition to that responsible for the synthesis of previously annotated protein-coding regions. Multiple short sequences have been found to be translated within single RNA molecules, both within annotated protein-coding and non-coding regions. The biological significance of this translation is a matter of intensive investigation. However, current schematic or annotation-based representations of mRNA translation generally do not account for the apparent multitude of translated regions within the same molecules. They also do not take into account the stochasticity of the process that allows alternative translations of the same RNA molecules by different ribosomes. There is a need for formal representations of mRNA complexity that would enable the analysis of quantitative information on translation and more accurate models for predicting the phenotypic effects of genetic variants affecting translation. To address this, we developed a conceptually novel abstraction that we term Ribosome Decision Graphs (RDGs). RDGs represent translation as multiple ribosome paths through untranslated and translated mRNA segments. We termed the later 'translons'. Non-deterministic events, such as initiation, re-initiation, selenocysteine insertion or ribosomal frameshifting are then represented as branching points. This representation allows for an adequate representation of eukaryotic translation complexity and focuses on locations critical for translation regulation. We show how RDGs can be used for depicting translated regions, analysis of genetic variation and quantitative genome-wide data on translation for characterisation of regulatory modulators of translation.
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Affiliation(s)
- Jack A S Tierney
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- SFI Centre for Research Training in Genomics Data Science, University College Cork, Cork, Ireland
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Håkon Tjeldnes
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Nicola Whiffin
- The Big Data Institute and Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Eivind Valen
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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5
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Langdon CG. Nuclear PTEN's Functions in Suppressing Tumorigenesis: Implications for Rare Cancers. Biomolecules 2023; 13:biom13020259. [PMID: 36830628 PMCID: PMC9953540 DOI: 10.3390/biom13020259] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/28/2023] [Indexed: 01/31/2023] Open
Abstract
Phosphatase and tensin homolog (PTEN) encodes a tumor-suppressive phosphatase with both lipid and protein phosphatase activity. The tumor-suppressive functions of PTEN are lost through a variety of mechanisms across a wide spectrum of human malignancies, including several rare cancers that affect pediatric and adult populations. Originally discovered and characterized as a negative regulator of the cytoplasmic, pro-oncogenic phosphoinositide-3-kinase (PI3K) pathway, PTEN is also localized to the nucleus where it can exert tumor-suppressive functions in a PI3K pathway-independent manner. Cancers can usurp the tumor-suppressive functions of PTEN to promote oncogenesis by disrupting homeostatic subcellular PTEN localization. The objective of this review is to describe the changes seen in PTEN subcellular localization during tumorigenesis, how PTEN enters the nucleus, and the spectrum of impacts and consequences arising from disrupted PTEN nuclear localization on tumor promotion. This review will highlight the immediate need in understanding not only the cytoplasmic but also the nuclear functions of PTEN to gain more complete insights into how important PTEN is in preventing human cancers.
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Affiliation(s)
- Casey G. Langdon
- Department of Pediatrics, Darby Children’s Research Institute, Medical University of South Carolina, Charleston, SC 29425, USA; ; Tel.: +1-(843)-792-9289
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
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6
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Fedorova AD, Kiniry SJ, Andreev DE, Mudge JM, Baranov PV. Thousands of human non-AUG extended proteoforms lack evidence of evolutionary selection among mammals. Nat Commun 2022; 13:7910. [PMID: 36564405 PMCID: PMC9789052 DOI: 10.1038/s41467-022-35595-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
The synthesis of most proteins begins at AUG codons, yet a small number of non-AUG initiated proteoforms are also known. Here we analyse a large number of publicly available Ribo-seq datasets to identify novel, previously uncharacterised non-AUG proteoforms using Trips-Viz implementation of a novel algorithm for detecting translated ORFs. In parallel we analyse genomic alignment of 120 mammals to identify evidence of protein coding evolution in sequences encoding potential extensions. Unexpectedly we find that the number of non-AUG proteoforms identified with ribosome profiling data greatly exceeds those with strong phylogenetic support suggesting their recent evolution. Our study argues that the protein coding potential of human genome greatly exceeds that detectable through comparative genomics and exposes the existence of multiple proteins encoded by the same genomic loci.
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Affiliation(s)
- Alla D Fedorova
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
- SFI Centre for Research Training in Genomics Data Science, University College Cork, Cork, Ireland.
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Dmitry E Andreev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
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7
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PTEN: An Emerging Potential Target for Therapeutic Intervention in Respiratory Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4512503. [PMID: 35814272 PMCID: PMC9262564 DOI: 10.1155/2022/4512503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 04/22/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022]
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a potent tumor suppressor that regulates several key cellular processes, including proliferation, survival, genomic integrity, migration, and invasion, via PI3K-dependent and independent mechanisms. A subtle decrease in PTEN levels or catalytic activity is implicated not only in cancer but also in a wide spectrum of other diseases, including various respiratory diseases. A systemic overview of the advances in the molecular and cellular mechanisms of PTEN involved in the initiation and progression of respiratory diseases may offer novel targets for the development of effective therapeutics for the treatment of respiratory diseases. In the present review, we highlight the novel findings emerging from current research on the role of PTEN expression and regulation in airway pathological conditions such as asthma/allergic airway inflammation, pulmonary hypertension (PAH), chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and other acute lung injuries (ALI). Moreover, we discuss the clinical implications of PTEN alteration and recently suggested therapeutic possibilities for restoration of PTEN expression and function in respiratory diseases.
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8
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Furin extracellularly cleaves secreted PTENα/β to generate C-terminal fragment with a tumor-suppressive role. Cell Death Dis 2022; 13:532. [PMID: 35668069 PMCID: PMC9170693 DOI: 10.1038/s41419-022-04988-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 01/21/2023]
Abstract
PTENα and PTENβ (PTENα/β), two long translational variants of phosphatase and tensin homolog on chromosome 10 (PTEN), exert distinct roles from canonical PTEN, including promoting carcinogenesis and accelerating immune-resistant cancer progression. However, their roles in carcinogenesis remain greatly unknown. Herein, we report that, after secreting into the extracellular space, PTENα/β proteins are efficiently cleaved into a short N-terminal and a long C-terminal fragment by the proprotein convertase Furin at a polyarginine stretch in their N-terminal extensions. Although secreted PTENα/β and their cleaved fragment cannot enter cells, treatment of the purified C-terminal fragment but not cleavage-resistant mutants of PTENα exerts a tumor-suppressive role in vivo. As a result, overexpression of cleavage-resistant PTENα mutants manifest a tumor-promoting role more profound than that of wild-type PTENα. In line with these, the C-terminal fragment is significantly downregulated in liver cancer tissues compared to paired normal tissues, which is consistent with the downregulated expression of Furin. Collectively, we show that extracellular PTENα/β present opposite effects on carcinogenesis from intracellular PTENα/β, and propose that the tumor-suppressive C-terminal fragment of PTENα/β might be used as exogenous agent to treat cancer.
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9
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Andreev DE, Loughran G, Fedorova AD, Mikhaylova MS, Shatsky IN, Baranov PV. Non-AUG translation initiation in mammals. Genome Biol 2022; 23:111. [PMID: 35534899 PMCID: PMC9082881 DOI: 10.1186/s13059-022-02674-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 04/14/2022] [Indexed: 12/12/2022] Open
Abstract
Recent proteogenomic studies revealed extensive translation outside of annotated protein coding regions, such as non-coding RNAs and untranslated regions of mRNAs. This non-canonical translation is largely due to start codon plurality within the same RNA. This plurality is often due to the failure of some scanning ribosomes to recognize potential start codons leading to initiation downstream—a process termed leaky scanning. Codons other than AUG (non-AUG) are particularly leaky due to their inefficiency. Here we discuss our current understanding of non-AUG initiation. We argue for a near-ubiquitous role of non-AUG initiation in shaping the dynamic composition of mammalian proteomes.
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10
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Ivanov IP, Saba JA, Fan CM, Wang J, Firth AE, Cao C, Green R, Dever TE. Evolutionarily conserved inhibitory uORFs sensitize Hox mRNA translation to start codon selection stringency. Proc Natl Acad Sci U S A 2022; 119:e2117226119. [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [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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Affiliation(s)
- Ivaylo P Ivanov
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892
| | - James A Saba
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Chen-Ming Fan
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
| | - Ji Wang
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Chune Cao
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892
| | - Rachel Green
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD 21205;
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Thomas E Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892;
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11
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Andreev DE, Baranov PV, Milogorodskii A, Rachinskii D. A deterministic model for non-monotone relationship between translation of upstream and downstream open reading frames. MATHEMATICAL MEDICINE AND BIOLOGY : A JOURNAL OF THE IMA 2021; 38:490-515. [PMID: 34718568 DOI: 10.1093/imammb/dqab015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 08/12/2021] [Accepted: 10/06/2021] [Indexed: 01/01/2023]
Abstract
Totally asymmetric simple exclusion process (TASEP) modelling was shown to offer a parsimonious explanation for the experimentally confirmed ability of a single upstream open reading frames (uORFs) to upregulate downstream translation during the integrated stress response. As revealed by numerical simulations, the model predicts that reducing the density of scanning ribosomes upstream of certain uORFs increases the flow of ribosomes downstream. To gain a better insight into the mechanism which ensures the non-monotone relation between the upstream and downstream flows, in this work, we propose a phenomenological deterministic model approximating the TASEP model of the translation process. We establish the existence of a stationary solution featuring the decreasing density along the uORF for the deterministic model. Further, we find an explicit non-monotone relation between the upstream ribosome density and the downstream flow for the stationary solution in the limit of increasing uORF length and increasingly leaky initiation. The stationary distribution of the TASEP model, the stationary solution of the deterministic model and the explicit limit are compared numerically.
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Affiliation(s)
- D E Andreev
- Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation, and Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - P V Baranov
- University College Cork, College Road, Cork, T12 K8AF, Ireland, and Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry (RAS), 16/10 Miklukho-Maklay str., Moscow, 117997, Russian Federation
| | - A Milogorodskii
- Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation, and Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - D Rachinskii
- Department of Mathematical Sciences, The University of Texas at Dallas, 800 W. Campbell Rd, Richardson, TX 75080, USA
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12
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Yi X, Wang Z, Xiong X, Zheng X, Peng G, Xu H, Wei Q, Li H, Zhu Y, Ai J. Preparation and characterization of a polyclonal antibody against PTEN-Long. Biotechnol Appl Biochem 2021; 69:1622-1632. [PMID: 34338347 DOI: 10.1002/bab.2232] [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: 12/14/2020] [Accepted: 07/30/2021] [Indexed: 02/05/2023]
Abstract
Phosphatase and tensin homolog-long (PTEN-L) is a translational isoform of PTEN, which exists in both intracellular and extracellular locations. Previous studies demonstrated that PTEN-L could inhibit oncogenesis due to its lipid phosphatase activity. However, recent studies found that PTEN-L could promote the proliferation of some types of cancer cells. Moreover, as a protein phosphatase, PTEN-L can suppress mitophagy by counteracting PTEN-induced putative kinase protein 1 (PINK1)-Parkin-mediated ubiquitin phosphorylation, namely, PTEN-L is critical for exploring the mitophagy progression and the treatment of mitochondrial diseases. Accounting for the critical functions of PTEN-L, its antibody can be used for the treatment or prognosis of tumors and mitochondrial diseases. Currently, the commercial antibody of PTEN-L is not available. In our study, the recombinant PTEN-L protein was expressed in Escherichia coli BL21 and used as an antigen to immunize Japan's big-eared white rabbit for the preparation of polyclonal antibody. The PTEN-L protein can be captured by PTEN-L antibody specifically and effectively. Taken together, a PTEN_L antibody is a valuable tool for further exploring the function of PTEN-L in oncogenesis and mitochondrial diseases, and it would be a new choice for the prognosis or treatment of cancer and mitochondrial diseases.
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Affiliation(s)
- Xianyanling Yi
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Zhihong Wang
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Xingyu Xiong
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaonan Zheng
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Ge Peng
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu, China
| | - Hang Xu
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Qiang Wei
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Hong Li
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Ye Zhu
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jianzhong Ai
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China.,Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
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13
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Grencewicz DJ, Romigh T, Thacker S, Abbas A, Jaini R, Luse D, Eng C. Redefining the PTEN promoter: Identification of novel upstream transcription start regions. Hum Mol Genet 2021; 30:2135-2148. [PMID: 34218272 DOI: 10.1093/hmg/ddab175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/19/2021] [Accepted: 06/23/2021] [Indexed: 11/14/2022] Open
Abstract
Germline mutation of PTEN is causally observed in Cowden syndrome (CS) and is one of the most common, penetrant risk genes for autism spectrum disorder (ASD). However, the majority of individuals who present with CS-like clinical features are PTEN-mutation negative. Reassessment of PTEN promoter regulation may help explain abnormal PTEN dosage, as only the minimal promoter and coding regions are currently included in diagnostic PTEN mutation analysis. Therefore, we reanalyzed the architecture of the PTEN promoter using next-generation sequencing datasets. Specifically, run-on sequencing assays identified two additional transcription start regions (TSRs) at -2053 and - 1906 basepairs from the canonical start of PTEN, thus extending the PTEN 5'UTR and redefining the PTEN promoter. We show that these novel upstream TSRs are active in cancer cell lines, human cancer, and normal tissue. Further, these TSRs can produce novel PTEN transcripts due to the introduction of new splice donors at -2041, -1826, and - 1355, which may allow for splicing out of the PTEN 5'UTR or the first and second exon in upstream-initiated transcripts. Combining ENCODE ChIP-seq and pertinent literature, we also compile and analyze all transcription factors (TFs) binding at the redefined PTEN locus. Enrichment analyses suggest that TFs bind specifically to the upstream TSRs may be implicated in inflammatory processes. Together, these data redefine the architecture of the PTEN promoter, an important step toward a comprehensive model of PTEN transcription regulation, a basis for future investigations into the new promoters' role in disease pathogenesis.
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Affiliation(s)
- Dennis J Grencewicz
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Todd Romigh
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Stetson Thacker
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ata Abbas
- Division of Hematology and Oncology, Department of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Developmental Therapeutics Program, CASE Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ritika Jaini
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Developmental Therapeutics Program, CASE Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Germline High Risk Focus Group, CASE Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Donal Luse
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Charis Eng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Germline High Risk Focus Group, CASE Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Center for Personalized Genetic Healthcare, Cleveland Clinic Community Care and Population Health, Cleveland, OH 44195, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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14
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Atkins JF, O’Connor KM, Bhatt PR, Loughran G. From Recoding to Peptides for MHC Class I Immune Display: Enriching Viral Expression, Virus Vulnerability and Virus Evasion. Viruses 2021; 13:1251. [PMID: 34199077 PMCID: PMC8310308 DOI: 10.3390/v13071251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/11/2021] [Accepted: 06/19/2021] [Indexed: 01/02/2023] Open
Abstract
Many viruses, especially RNA viruses, utilize programmed ribosomal frameshifting and/or stop codon readthrough in their expression, and in the decoding of a few a UGA is dynamically redefined to specify selenocysteine. This recoding can effectively increase viral coding capacity and generate a set ratio of products with the same N-terminal domain(s) but different C-terminal domains. Recoding can also be regulatory or generate a product with the non-universal 21st directly encoded amino acid. Selection for translation speed in the expression of many viruses at the expense of fidelity creates host immune defensive opportunities. In contrast to host opportunism, certain viruses, including some persistent viruses, utilize recoding or adventitious frameshifting as part of their strategy to evade an immune response or specific drugs. Several instances of recoding in small intensively studied viruses escaped detection for many years and their identification resolved dilemmas. The fundamental importance of ribosome ratcheting is consistent with the initial strong view of invariant triplet decoding which however did not foresee the possibility of transitory anticodon:codon dissociation. Deep level dynamics and structural understanding of recoding is underway, and a high level structure relevant to the frameshifting required for expression of the SARS CoV-2 genome has just been determined.
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Affiliation(s)
- John F. Atkins
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
| | - Kate M. O’Connor
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
| | - Pramod R. Bhatt
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Gary Loughran
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
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15
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Reprogramming translation for gene therapy. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 182:439-476. [PMID: 34175050 DOI: 10.1016/bs.pmbts.2021.01.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Translational control plays a fundamental role in the regulation of gene expression in eukaryotes. Modulating translational efficiency allows the cell to fine-tune the expression of genes, spatially control protein localization, and trigger fast responses to environmental stresses. Translational regulation involves mechanisms acting on multiple steps of the protein synthesis pathway: initiation, elongation, and termination. Many cis-acting elements present in the 5' UTR of transcripts can influence translation at the initiation step. Among them, the Kozak sequence impacts translational efficiency by regulating the recognition of the start codon; upstream open reading frames (uORFs) are associated with inhibition of translation of the downstream protein; internal ribosomal entry sites (IRESs) can promote cap-independent translation. CRISPR-Cas technology is a revolutionary gene-editing tool that has also been applied to the regulation of gene expression. In this chapter, we focus on the genome editing approaches developed to modulate the translational efficiency with the aim to find novel therapeutic approaches, in particular acting on the cis-elements, that regulate the initiation of protein synthesis.
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16
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Unusually efficient CUG initiation of an overlapping reading frame in POLG mRNA yields novel protein POLGARF. Proc Natl Acad Sci U S A 2020; 117:24936-24946. [PMID: 32958672 DOI: 10.1073/pnas.2001433117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
While near-cognate codons are frequently used for translation initiation in eukaryotes, their efficiencies are usually low (<10% compared to an AUG in optimal context). Here, we describe a rare case of highly efficient near-cognate initiation. A CUG triplet located in the 5' leader of POLG messenger RNA (mRNA) initiates almost as efficiently (∼60 to 70%) as an AUG in optimal context. This CUG directs translation of a conserved 260-triplet-long overlapping open reading frame (ORF), which we call POLGARF (POLG Alternative Reading Frame). Translation of a short upstream ORF 5' of this CUG governs the ratio between POLG (the catalytic subunit of mitochondrial DNA polymerase) and POLGARF synthesized from a single POLG mRNA. Functional investigation of POLGARF suggests a role in extracellular signaling. While unprocessed POLGARF localizes to the nucleoli together with its interacting partner C1QBP, serum stimulation results in rapid cleavage and secretion of a POLGARF C-terminal fragment. Phylogenetic analysis shows that POLGARF evolved ∼160 million y ago due to a mammalian-wide interspersed repeat (MIR) transposition into the 5' leader sequence of the mammalian POLG gene, which became fixed in placental mammals. This discovery of POLGARF unveils a previously undescribed mechanism of de novo protein-coding gene evolution.
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17
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Akirtava C, McManus CJ. Control of translation by eukaryotic mRNA transcript leaders-Insights from high-throughput assays and computational modeling. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1623. [PMID: 32869519 DOI: 10.1002/wrna.1623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/23/2020] [Accepted: 07/30/2020] [Indexed: 12/21/2022]
Abstract
Eukaryotic gene expression is tightly regulated during translation of mRNA to protein. Mis-regulation of translation can lead to aberrant proteins which accumulate in cancers and cause neurodegenerative diseases. Foundational studies on model genes established fundamental roles for mRNA 5' transcript leader (TL) sequences in controlling ribosome recruitment, scanning, and initiation. TL cis-regulatory elements and their corresponding trans-acting factors control cap-dependent initiation under unstressed conditions. Under stress, cap-dependent initiation is suppressed, and specific mRNA structures and sequences promote translation of stress-responsive transcripts to remodel the proteome. In this review, we summarize current knowledge of TL functions in translation initiation. We focus on insights from high-throughput analyses of ribosome occupancy, mRNA structure, RNA Binding Protein occupancy, and massively parallel reporter assays. These data-driven approaches, coupled with computational analyses and modeling, have paved the way for a comprehensive understanding of TL functions. Finally, we will discuss areas of future research on the roles of mRNA sequences and structures in translation. This article is categorized under: Translation > Translation Mechanisms RNA Evolution and Genomics > Computational Analyses of RNA RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Christina Akirtava
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Charles Joel McManus
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Computational Biology Department, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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18
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Haddadi N, Travis G, Nassif NT, Simpson AM, Marsh DJ. Toward Systems Pathology for PTEN Diagnostics. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a037127. [PMID: 31615872 DOI: 10.1101/cshperspect.a037127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Germline alterations of the tumor suppressor PTEN have been extensively characterized in patients with PTEN hamartoma tumor syndromes, encompassing subsets of Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, Proteus and Proteus-like syndromes, as well as autism spectrum disorder. Studies have shown an increase in the risk of developing specific cancer types in the presence of a germline PTEN mutation. Furthermore, outside of the familial setting, somatic variants of PTEN occur in numerous malignancies. Here we introduce and discuss the prospect of moving toward a systems pathology approach for PTEN diagnostics, incorporating clinical and molecular pathology data with the goal of improving the clinical management of patients with a PTEN mutation. Detection of a germline PTEN mutation can inform cancer surveillance and in the case of somatic mutation, have value in predicting disease course. Given that PTEN functions in the PI3K/AKT/mTOR pathway, identification of a PTEN mutation may highlight new therapeutic opportunities and/or inform therapeutic choices.
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Affiliation(s)
- Nahal Haddadi
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Glena Travis
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Najah T Nassif
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,Centre for Health Technologies, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Ann M Simpson
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,Centre for Health Technologies, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Deborah J Marsh
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,Centre for Health Technologies, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,Translational Oncology Group, School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,Northern Clinical School, Kolling Institute, Faculty of Medicine and Health, University of Sydney, New South Wales 2006, Australia
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19
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Kiniry SJ, Michel AM, Baranov PV. Computational methods for ribosome profiling data analysis. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1577. [PMID: 31760685 DOI: 10.1002/wrna.1577] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/12/2019] [Accepted: 10/16/2019] [Indexed: 12/15/2022]
Abstract
Since the introduction of the ribosome profiling technique in 2009 its popularity has greatly increased. It is widely used for the comprehensive assessment of gene expression and for studying the mechanisms of regulation at the translational level. As the number of ribosome profiling datasets being produced continues to grow, so too does the need for reliable software that can provide answers to the biological questions it can address. This review describes the computational methods and tools that have been developed to analyze ribosome profiling data at the different stages of the process. It starts with initial routine processing of raw data and follows with more specific tasks such as the identification of translated open reading frames, differential gene expression analysis, or evaluation of local or global codon decoding rates. The review pinpoints challenges associated with each step and explains the ways in which they are currently addressed. In addition it provides a comprehensive, albeit incomplete, list of publicly available software applicable to each step, which may be a beneficial starting point to those unexposed to ribosome profiling analysis. The outline of current challenges in ribosome profiling data analysis may inspire computational biologists to search for novel, potentially superior, solutions that will improve and expand the bioinformatician's toolbox for ribosome profiling data analysis. This article is characterized under: Translation > Ribosome Structure/Function RNA Evolution and Genomics > Computational Analyses of RNA Translation > Translation Mechanisms Translation > Translation Regulation.
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Affiliation(s)
- Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Audrey M Michel
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
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20
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Abstract
The tumor suppressor phosphatase and tensin homolog on chromosome 10 (PTEN) is a tightly regulated enzyme responsible for dephosphorylating the progrowth lipid messenger molecule phosphatidylinositol 3,4,5-trisphosphate (PIP3) on the plasma membrane. The carboxy-terminal tail (CTT) of PTEN is key for regulation of the enzyme. When phosphorylated, the unstructured CTT interacts with the phosphatase-C2 superdomain to inactivate the enzyme by preventing membrane association. PTEN mutations associated with cancer also inactivate the enzyme. Alternate translation-initiation sites generate extended isoforms of PTEN, such as PTEN-L that has multiple roles in cells. The extended amino-terminal region bears a signal sequence and a polyarginine sequence to facilitate exit from and entry into cells, respectively, and a membrane-binding helix that activates the enzyme. This amino-terminal region also facilitates mitochondrial and nucleolar localization. This review explores PTEN structure and its impact on localization and regulation.
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21
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Manjunath H, Zhang H, Rehfeld F, Han J, Chang TC, Mendell JT. Suppression of Ribosomal Pausing by eIF5A Is Necessary to Maintain the Fidelity of Start Codon Selection. Cell Rep 2019; 29:3134-3146.e6. [PMID: 31801078 PMCID: PMC6917043 DOI: 10.1016/j.celrep.2019.10.129] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022] Open
Abstract
Sequences within 5' UTRs dictate the site and efficiency of translation initiation. In this study, an unbiased screen designed to interrogate the 5' UTR-mediated regulation of the growth-promoting gene MYC unexpectedly revealed the ribosomal pause relief factor eIF5A as a regulator of translation initiation codon selection. Depletion of eIF5A enhances upstream translation within 5' UTRs across yeast and human transcriptomes, including on the MYC transcript, where this results in increased production of an N-terminally extended protein. Furthermore, ribosome profiling experiments established that the function of eIF5A as a suppressor of ribosomal pausing at sites of suboptimal peptide bond formation is conserved in human cells. We present evidence that proximal ribosomal pausing on a transcript triggers enhanced use of upstream suboptimal or non-canonical initiation codons. Thus, we propose that eIF5A functions not only to maintain efficient translation elongation in eukaryotic cells but also to maintain the fidelity of translation initiation.
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Affiliation(s)
- Hema Manjunath
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - He Zhang
- Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA; Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA
| | - Frederick Rehfeld
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Jaeil Han
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Joshua T Mendell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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22
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Monteuuis G, Miścicka A, Świrski M, Zenad L, Niemitalo O, Wrobel L, Alam J, Chacinska A, Kastaniotis AJ, Kufel J. Non-canonical translation initiation in yeast generates a cryptic pool of mitochondrial proteins. Nucleic Acids Res 2019; 47:5777-5791. [PMID: 31216041 PMCID: PMC6582344 DOI: 10.1093/nar/gkz301] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/12/2019] [Accepted: 04/16/2019] [Indexed: 12/15/2022] Open
Abstract
Utilization of non-AUG alternative translation start sites is most common in bacteria and viruses, but it has been also reported in other organisms. This phenomenon increases proteome complexity by allowing expression of multiple protein isoforms from a single gene. In Saccharomyces cerevisiae, a few described cases concern proteins that are translated from upstream near-cognate start codons as N-terminally extended variants that localize to mitochondria. Using bioinformatics tools, we provide compelling evidence that in yeast the potential for producing alternative protein isoforms by non-AUG translation initiation is much more prevalent than previously anticipated and may apply to as many as a few thousand proteins. Several hundreds of candidates are predicted to gain a mitochondrial targeting signal (MTS), generating an unrecognized pool of mitochondrial proteins. We confirmed mitochondrial localization of a subset of proteins previously not identified as mitochondrial, whose standard forms do not carry an MTS. Our data highlight the potential of non-canonical translation initiation in expanding the capacity of the mitochondrial proteome and possibly also other cellular features.
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Affiliation(s)
- Geoffray Monteuuis
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Anna Miścicka
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Lounis Zenad
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Olli Niemitalo
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Lidia Wrobel
- International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Jahangir Alam
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Agnieszka Chacinska
- International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.,Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Alexander J Kastaniotis
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
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23
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Pulido R, Mingo J, Gaafar A, Nunes-Xavier CE, Luna S, Torices L, Angulo JC, López JI. Precise Immunodetection of PTEN Protein in Human Neoplasia. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a036293. [PMID: 31501265 DOI: 10.1101/cshperspect.a036293] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PTEN is a major tumor-suppressor protein whose expression and biological activity are frequently diminished in sporadic or inherited cancers. PTEN gene deletion or loss-of-function mutations favor tumor cell growth and are commonly found in clinical practice. In addition, diminished PTEN protein expression is also frequently observed in tumor samples from cancer patients in the absence of PTEN gene alterations. This makes PTEN protein levels a potential biomarker parameter in clinical oncology, which can guide therapeutic decisions. The specific detection of PTEN protein can be achieved by using highly defined anti-PTEN monoclonal antibodies (mAbs), characterized with precision in terms of sensitivity for the detection technique, specificity for PTEN binding, and constraints of epitope recognition. This is especially relevant taking into consideration that PTEN is highly targeted by mutations and posttranslational modifications, and different PTEN protein isoforms exist. The precise characterization of anti-PTEN mAb reactivity is an important step in the validation of these reagents as diagnostic and prognostic tools in clinical oncology, including their routine use in analytical immunohistochemistry (IHC). Here, we review the current status on the use of well-defined anti-PTEN mAbs for PTEN immunodetection in the clinical context and discuss their potential usefulness and limitations for a more precise cancer diagnosis and patient benefit.
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Affiliation(s)
- Rafael Pulido
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao 48011, Spain
| | - Janire Mingo
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain
| | - Ayman Gaafar
- Department of Pathology, Cruces University Hospital, Barakaldo 48903, Spain
| | - Caroline E Nunes-Xavier
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain.,Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo N-0310, Norway
| | - Sandra Luna
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain
| | - Leire Torices
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain
| | - Javier C Angulo
- Department of Urology, University Hospital of Getafe, Getafe, Madrid 28904, Spain.,Clinical Department, European University of Madrid, Laureate Universities, Madrid 28904, Spain
| | - José I López
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain.,Department of Pathology, Cruces University Hospital, Barakaldo 48903, Spain.,University of the Basque Country, Leioa 48940, Spain
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24
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Fernández-Acero T, Bertalmio E, Luna S, Mingo J, Bravo-Plaza I, Rodríguez-Escudero I, Molina M, Pulido R, Cid VJ. Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function. Cells 2019; 8:cells8121512. [PMID: 31779149 PMCID: PMC6952770 DOI: 10.3390/cells8121512] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/21/2019] [Accepted: 11/22/2019] [Indexed: 12/21/2022] Open
Abstract
The tumour suppressor PTEN is frequently downregulated, mutated or lost in several types of tumours and congenital disorders including PHTS (PTEN Hamartoma Tumour Syndrome) and ASD (Autism Spectrum Disorder). PTEN is a lipid phosphatase whose activity over the lipid messenger PIP3 counteracts the stimulation of the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway. Recently, several extended versions of PTEN produced in the cell by alternative translation initiation have been described, among which, PTEN-L and PTEN-M represent the longest isoforms. We previously developed a humanized yeast model in which the expression of PI3K in Saccharomyces cerevisiae led to growth inhibition that could be suppressed by co-expression of PTEN. Here, we show that the expression of PTEN-L and PTEN-M in yeast results in robust counteracting of PI3K-dependent growth inhibition. N-terminally tagged GFP-PTEN-L was sharply localized at the yeast plasma membrane. Point mutations of a putative membrane-binding helix located at the PTEN-L extension or its deletion shifted localization to nuclear. Also, a shift from plasma membrane to nucleus was observed in mutants at basic amino acid clusters at the PIP2-binding motif, and at the Cα2 and CBR3 loops at the C2 domain. In contrast, C-terminally tagged PTEN-L-GFP displayed mitochondrial localization in yeast, which was shifted to plasma membrane by removing the first 22 PTEN-L residues. Our results suggest an important role of the N-terminal extension of alternative PTEN isoforms on their spatial and functional regulation.
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Affiliation(s)
- Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Eleonora Bertalmio
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Sandra Luna
- Instituto de Investigación Sanitaria Biocruces Bizkaia, 48903 Barakaldo, Spain; (S.L.); (J.M.)
| | - Janire Mingo
- Instituto de Investigación Sanitaria Biocruces Bizkaia, 48903 Barakaldo, Spain; (S.L.); (J.M.)
| | - Ignacio Bravo-Plaza
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Isabel Rodríguez-Escudero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Rafael Pulido
- Instituto de Investigación Sanitaria Biocruces Bizkaia, 48903 Barakaldo, Spain; (S.L.); (J.M.)
- IKERBASQUE, Fundación Vasca para la Ciencia, 48011 Bilbao, Spain
- Correspondence: (R.P.); (V.J.C.)
| | - Víctor J. Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
- Correspondence: (R.P.); (V.J.C.)
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25
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Petersen SD, Zhang J, Lee JS, Jakociunas T, Grav LM, Kildegaard HF, Keasling JD, Jensen MK. Modular 5'-UTR hexamers for context-independent tuning of protein expression in eukaryotes. Nucleic Acids Res 2019; 46:e127. [PMID: 30124898 PMCID: PMC6265478 DOI: 10.1093/nar/gky734] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 08/01/2018] [Indexed: 11/25/2022] Open
Abstract
Functional characterization of regulatory DNA elements in broad genetic contexts is a prerequisite for forward engineering of biological systems. Translation initiation site (TIS) sequences are attractive to use for regulating gene activity and metabolic pathway fluxes because the genetic changes are minimal. However, limited knowledge is available on tuning gene outputs by varying TISs in different genetic and environmental contexts. Here, we created TIS hexamer libraries in baker’s yeast Saccharomyces cerevisiae directly 5′ end of a reporter gene in various promoter contexts and measured gene activity distributions for each library. Next, selected TIS sequences, resulted in almost 10-fold changes in reporter outputs, were experimentally characterized in various environmental and genetic contexts in both yeast and mammalian cells. From our analyses, we observed strong linear correlations (R2 = 0.75–0.98) between all pairwise combinations of TIS order and gene activity. Finally, our analysis enabled the identification of a TIS with almost 50% stronger output than a commonly used TIS for protein expression in mammalian cells, and selected TISs were also used to tune gene activities in yeast at a metabolic branch point in order to prototype fitness and carotenoid production landscapes. Taken together, the characterized TISs support reliable context-independent forward engineering of translation initiation in eukaryotes.
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Affiliation(s)
- Søren D Petersen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Jie Zhang
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Jae S Lee
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Tadas Jakociunas
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Lise M Grav
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Helene F Kildegaard
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Jay D Keasling
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.,Joint BioEnergy Institute, Emeryville, CA 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.,Department of Bioengineering, University of California, Berkeley, CA 94720, USA.,Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes of Advanced Technologies, Shenzhen 518055, China
| | - Michael K Jensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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26
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Palumbo E, Zhao B, Xue B, Uversky VN, Davé V. Analyzing aggregation propensities of clinically relevant PTEN mutants: a new culprit in pathogenesis of cancer and other PTENopathies. J Biomol Struct Dyn 2019; 38:2253-2266. [PMID: 31232187 DOI: 10.1080/07391102.2019.1630005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
While studies on pathological protein aggregation are largely limited to neurodegenerative disease, emerging evidence suggests that other diseases are also associated with pathogenic protein aggregation. For example, tumor suppressor protein p53, and its mutant conformers, undergo protein aggregation, exacerbating the cancer phenotype. These findings raise the possibility that inactivation of tumor suppressors via protein aggregation may participate in cancer and other disease pathologies. Since tumor suppressor protein PTEN has similar functions to p53, and is mutated in multiple diseases, we examined the aggregation propensity of PTEN wild-type and 1523 clinically relevant PTEN mutants. Applying computational tools to PTEN mutation databases revealed that PTEN wild-type protein can aggregate under physiological conditions, and 274 distinct PTEN mutants had increased aggregation propensity. To understand the mechanism underlying PTEN conformer aggregation, we analyzed the physicochemical properties of these 274 PTEN mutants and defined their aggregation potential. We conclude that increased aggregation propensity of select PTEN mutants may contribute to disease phenotypes. Our studies have built the foundation for interrogating the aggregation potential of these select mutants in cancers and in PTENopathies. Elucidating the pathogenic mechanisms associated with aggregation-prone PTEN conformers will aid in developing therapies that target PTEN-aggregates in multiple diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Emily Palumbo
- Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Bi Zhao
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Bin Xue
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA.,Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Vrushank Davé
- Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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27
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Coronas-Serna JM, Valenti M, Del Val E, Fernández-Acero T, Rodríguez-Escudero I, Mingo J, Luna S, Torices L, Pulido R, Molina M, Cid VJ. Modeling human disease in yeast: recreating the PI3K-PTEN-Akt signaling pathway in Saccharomyces cerevisiae. Int Microbiol 2019; 23:75-87. [PMID: 31218536 DOI: 10.1007/s10123-019-00082-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/08/2019] [Accepted: 04/23/2019] [Indexed: 12/11/2022]
Abstract
The yeast Saccharomyces cerevisiae is a model organism that has been thoroughly exploited to understand the universal mechanisms that govern signaling pathways. Due to its ease of manipulation, humanized yeast models that successfully reproduce the function of human genes permit the development of highly efficient genetic approaches for molecular studies. Of special interest are those pathways related to human disease that are conserved from yeast to mammals. However, it is also possible to engineer yeast cells to implement functions that are naturally absent in fungi. Along the years, we have reconstructed several aspects of the mammalian phosphatidylinositol 3-kinase (PI3K) pathway in S. cerevisiae. Here, we briefly review the use of S. cerevisiae as a tool to study human oncogenes and tumor suppressors, and we present an overview of the models applied to the study of the PI3K oncoproteins, the tumor suppressor PTEN, and the Akt protein kinase. We discuss the application of these models to study the basic functional properties of these signaling proteins, the functional assessment of their clinically relevant variants, and the design of feasible platforms for drug discovery.
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Affiliation(s)
- Julia María Coronas-Serna
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Marta Valenti
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Elba Del Val
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Isabel Rodríguez-Escudero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Janire Mingo
- Biomarkers in Cancer Unit, Biocruces Health Research Institute, 48903, Barakaldo, Bizkaia, Spain
| | - Sandra Luna
- Biomarkers in Cancer Unit, Biocruces Health Research Institute, 48903, Barakaldo, Bizkaia, Spain
| | - Leire Torices
- Biomarkers in Cancer Unit, Biocruces Health Research Institute, 48903, Barakaldo, Bizkaia, Spain
| | - Rafael Pulido
- Biomarkers in Cancer Unit, Biocruces Health Research Institute, 48903, Barakaldo, Bizkaia, Spain
- Ikerbasque, Basque Foundation for Science, 48011, Bilbao, Spain
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Víctor J Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Pza. Ramón y Cajal s/n, 28040, Madrid, Spain.
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28
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Andreev DE, Arnold M, Kiniry SJ, Loughran G, Michel AM, Rachinskii D, Baranov PV. TASEP modelling provides a parsimonious explanation for the ability of a single uORF to derepress translation during the integrated stress response. eLife 2018; 7:32563. [PMID: 29932418 PMCID: PMC6033536 DOI: 10.7554/elife.32563] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 06/21/2018] [Indexed: 12/13/2022] Open
Abstract
Translation initiation is the rate-limiting step of protein synthesis that is downregulated during the Integrated Stress Response (ISR). Previously, we demonstrated that most human mRNAs that are resistant to this inhibition possess translated upstream open reading frames (uORFs), and that in some cases a single uORF is sufficient for the resistance. Here we developed a computational model of Initiation Complexes Interference with Elongating Ribosomes (ICIER) to gain insight into the mechanism. We explored the relationship between the flux of scanning ribosomes upstream and downstream of a single uORF depending on uORF features. Paradoxically, our analysis predicts that reducing ribosome flux upstream of certain uORFs increases initiation downstream. The model supports the derepression of downstream translation as a general mechanism of uORF-mediated stress resistance. It predicts that stress resistance can be achieved with long slowly decoded uORFs that do not favor translation reinitiation and that start with initiators of low leakiness.
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Affiliation(s)
- Dmitry E Andreev
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Maxim Arnold
- Department of Mathematical Sciences, The University of Texas at Dallas, Richardson, United States
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Audrey M Michel
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Dmitrii Rachinskii
- Department of Mathematical Sciences, The University of Texas at Dallas, Richardson, United States
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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29
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Targeting PTEN in Colorectal Cancers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1110:55-73. [DOI: 10.1007/978-3-030-02771-1_5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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30
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Tang L, Morris J, Wan J, Moore C, Fujita Y, Gillaspie S, Aube E, Nanda J, Marques M, Jangal M, Anderson A, Cox C, Hiraishi H, Dong L, Saito H, Singh CR, Witcher M, Topisirovic I, Qian SB, Asano K. Competition between translation initiation factor eIF5 and its mimic protein 5MP determines non-AUG initiation rate genome-wide. Nucleic Acids Res 2017; 45:11941-11953. [PMID: 28981728 PMCID: PMC5714202 DOI: 10.1093/nar/gkx808] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 08/31/2017] [Indexed: 12/27/2022] Open
Abstract
In the human genome, translation initiation from non-AUG codons plays an important role in various gene regulation programs. However, mechanisms regulating the non-AUG initiation rate remain poorly understood. Here, we show that the non-AUG initiation rate is nearly consistent under a fixed nucleotide context in various human and insect cells. Yet, it ranges from <1% to nearly 100% compared to AUG translation, depending on surrounding sequences, including Kozak, and possibly additional nucleotide contexts. Mechanistically, this range of non-AUG initiation is controlled in part, by the eIF5-mimic protein (5MP). 5MP represses non-AUG translation by competing with eIF5 for the Met-tRNAi-binding factor eIF2. Consistently, eIF5 increases, whereas 5MP decreases translation of NAT1/EIF4G2/DAP5, whose sole start codon is GUG. By modulating eIF5 and 5MP1 expression in combination with ribosome profiling we identified a handful of previously unknown non-AUG initiation sites, some of which serve as the exclusive start codons. If the initiation rate for these codons is low, then an AUG-initiated downstream ORF prevents the generation of shorter, AUG-initiated isoforms. We propose that the homeostasis of the non-AUG translatome is maintained through balanced expression of eIF5 and 5MP.
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Affiliation(s)
- Leiming Tang
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Jacob Morris
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Ji Wan
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Chelsea Moore
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Yoshihiko Fujita
- Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Sarah Gillaspie
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Eric Aube
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | | | - Maud Marques
- Lady Davis Institute, and the Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Maika Jangal
- Lady Davis Institute, and the Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Abbey Anderson
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Christian Cox
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Hiroyuki Hiraishi
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Leiming Dong
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Hirohide Saito
- Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Chingakham Ranjit Singh
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Michael Witcher
- Lady Davis Institute, and the Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Ivan Topisirovic
- Lady Davis Institute, and the Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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31
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PTEN-L promotes type I interferon responses and antiviral immunity. Cell Mol Immunol 2017; 15:48-57. [PMID: 29057971 DOI: 10.1038/cmi.2017.102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 01/16/2023] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a well-known tumor suppressor that acts as a dual-specificity phosphatase and is frequently mutated in human cancer. Our previous work has demonstrated that PTEN also plays a vital role in type I interferon responses and antiviral innate immunity. Recently, a translational variant of PTEN with a long N-terminal extension (PTEN-L) has been discovered that is secreted into the extracellular environment and enters recipient cells, where it exerts a phosphatase function antagonistic to PI3K/Akt signaling and tumorigenesis. In this study, we demonstrate that PTEN-L promotes type I interferon responses and antiviral innate immunity during viral infection in a phosphatase activity-dependent manner. Compared with canonical PTEN, PTEN-L also exerts its antiviral function when it is applied exogenously in protein form. This finding was confirmed in cell cultures and mouse infection models. Furthermore, PTEN-L enhances the responses of both type I interferon and proinflammatory cytokines, thus suggesting that PTEN-L might possess additional functions compared with those of PTEN. Thus, the antiviral function of PTEN-L may open an avenue for the use of PTEN-L in antiviral therapy, particularly in patients with PTEN-deficient tumors.
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32
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Fijalkowska D, Verbruggen S, Ndah E, Jonckheere V, Menschaert G, Van Damme P. eIF1 modulates the recognition of suboptimal translation initiation sites and steers gene expression via uORFs. Nucleic Acids Res 2017; 45:7997-8013. [PMID: 28541577 PMCID: PMC5570006 DOI: 10.1093/nar/gkx469] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/11/2017] [Indexed: 12/25/2022] Open
Abstract
Alternative translation initiation mechanisms such as leaky scanning and reinitiation potentiate the polycistronic nature of human transcripts. By allowing for reprogrammed translation, these mechanisms can mediate biological responses to stimuli. We combined proteomics with ribosome profiling and mRNA sequencing to identify the biological targets of translation control triggered by the eukaryotic translation initiation factor 1 (eIF1), a protein implicated in the stringency of start codon selection. We quantified expression changes of over 4000 proteins and 10 000 actively translated transcripts, leading to the identification of 245 transcripts undergoing translational control mediated by upstream open reading frames (uORFs) upon eIF1 deprivation. Here, the stringency of start codon selection and preference for an optimal nucleotide context were largely diminished leading to translational upregulation of uORFs with suboptimal start. Interestingly, genes affected by eIF1 deprivation were implicated in energy production and sensing of metabolic stress.
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Affiliation(s)
- Daria Fijalkowska
- VIB-UGent Center for Medical Biotechnology, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Steven Verbruggen
- Lab of Bioinformatics and Computational Genomics, Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, B-9000 Ghent, Belgium
| | - Elvis Ndah
- VIB-UGent Center for Medical Biotechnology, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium.,Lab of Bioinformatics and Computational Genomics, Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, B-9000 Ghent, Belgium
| | - Veronique Jonckheere
- VIB-UGent Center for Medical Biotechnology, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Gerben Menschaert
- Lab of Bioinformatics and Computational Genomics, Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, B-9000 Ghent, Belgium
| | - Petra Van Damme
- VIB-UGent Center for Medical Biotechnology, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
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33
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Malaney P, Uversky VN, Davé V. PTEN proteoforms in biology and disease. Cell Mol Life Sci 2017; 74:2783-2794. [PMID: 28289760 PMCID: PMC11107534 DOI: 10.1007/s00018-017-2500-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/23/2017] [Accepted: 03/02/2017] [Indexed: 01/30/2023]
Abstract
Proteoforms are specific molecular forms of protein products arising from a single gene that possess different structures and different functions. Therefore, a single gene can produce a large repertoire of proteoforms by means of allelic variations (mutations, indels, SNPs), alternative splicing and other pre-translational mechanisms, post-translational modifications (PTMs), conformational dynamics, and functioning. Resulting proteoforms that have different sizes, alternative splicing patterns, sets of post-translational modifications, protein-protein interactions, and protein-ligand interactions, might dramatically increase the functionality of the encoded protein. Herein, we have interrogated the tumor suppressor PTEN for its proteoforms and find that this protein exists in multiple forms with distinct functions and sub-cellular localizations. Furthermore, the levels of each PTEN proteoform in a given cell may affect its biological function. Indeed, the paradigm of the continuum model of tumor suppression by PTEN can be better explained by the presence of a continuum of PTEN proteoforms, diversity, and levels of which are associated with pathological outcomes than simply by the different roles of mutations in the PTEN gene. Consequently, understanding the mechanisms underlying the dysregulation of PTEN proteoforms by several genomic and non-genomic mechanisms in cancer and other diseases is imperative. We have identified different PTEN proteoforms, which control various aspects of cellular function and grouped them into three categories of intrinsic, function-induced, and inducible proteoforms. A special emphasis is given to the inducible PTEN proteoforms that are produced due to alternative translational initiation. The novel finding that PTEN forms dimers with biological implications supports the notion that PTEN proteoform-proteoform interactions may play hitherto unknown roles in cellular homeostasis and in pathogenic settings, including cancer. These PTEN proteoforms with unique properties and functionalities offer potential novel therapeutic opportunities in the treatment of various cancers and other diseases.
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Affiliation(s)
- Prerna Malaney
- Department of Pathology and Cell Biology, Morsani College of Medicine, MDC 64, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, Tampa, FL, 33612, USA
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave., Saint Petersburg, Russia, 194064
| | - Vrushank Davé
- Department of Pathology and Cell Biology, Morsani College of Medicine, MDC 64, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA.
- Department of Oncological Sciences, Morsani College of Medicine, University of South Florida, Bruce B. Downs Blvd, Tampa, FL, 33612, USA.
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34
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Translation Initiation from Conserved Non-AUG Codons Provides Additional Layers of Regulation and Coding Capacity. mBio 2017; 8:mBio.00844-17. [PMID: 28655822 PMCID: PMC5487733 DOI: 10.1128/mbio.00844-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neurospora crassa cpc-1 and Saccharomyces cerevisiae GCN4 are homologs specifying transcription activators that drive the transcriptional response to amino acid limitation. The cpc-1 mRNA contains two upstream open reading frames (uORFs) in its >700-nucleotide (nt) 5′ leader, and its expression is controlled at the level of translation in response to amino acid starvation. We used N. crassa cell extracts and obtained data indicating that cpc-1 uORF1 and uORF2 are functionally analogous to GCN4 uORF1 and uORF4, respectively, in controlling translation. We also found that the 5′ region upstream of the main coding sequence of the cpc-1 mRNA extends for more than 700 nucleotides without any in-frame stop codon. For 100 cpc-1 homologs from Pezizomycotina and from selected Basidiomycota, 5′ conserved extensions of the CPC1 reading frame are also observed. Multiple non-AUG near-cognate codons (NCCs) in the CPC1 reading frame upstream of uORF2, some deeply conserved, could potentially initiate translation. At least four NCCs initiated translation in vitro. In vivo data were consistent with initiation at NCCs to produce N-terminally extended N. crassa CPC1 isoforms. The pivotal role played by CPC1, combined with its translational regulation by uORFs and NCC utilization, underscores the emerging significance of noncanonical initiation events in controlling gene expression. There is a deepening and widening appreciation of the diverse roles of translation in controlling gene expression. A central fungal transcription factor, the best-studied example of which is Saccharomyces cerevisiae GCN4, is crucial for the response to amino acid limitation. Two upstream open reading frames (uORFs) in the GCN4 mRNA are critical for controlling GCN4 synthesis. We observed that two uORFs in the corresponding Neurospora crassa cpc-1 mRNA appear functionally analogous to the GCN4 uORFs. We also discovered that, surprisingly, unlike GCN4, the CPC1 coding sequence extends far upstream from the presumed AUG start codon with no other in-frame AUG codons. Similar extensions were seen in homologs from many filamentous fungi. We observed that multiple non-AUG near-cognate codons (NCCs) in this extended reading frame, some conserved, initiated translation to produce longer forms of CPC1, underscoring the significance of noncanonical initiation in controlling gene expression.
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