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Kempa M, Mikołajczak K, Ogrodowicz P, Pniewski T, Krajewski P, Kuczyńska A. The impact of multiple abiotic stresses on ns-LTP2.8 gene transcript and ns-LTP2.8 protein accumulation in germinating barley (Hordeum vulgare L.) embryos. PLoS One 2024; 19:e0299400. [PMID: 38502680 PMCID: PMC10950244 DOI: 10.1371/journal.pone.0299400] [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: 10/10/2023] [Accepted: 02/09/2024] [Indexed: 03/21/2024] Open
Abstract
Abiotic stresses occur more often in combination than alone under regular field conditions limiting in more severe way crop production. Stress recognition in plants primarily occurs in the plasma membrane, modification of which is necessary to maintain homeostasis in response to it. It is known that lipid transport proteins (ns-LTPs) participate in modification of the lipidome of cell membranes. Representative of this group, ns-LTP2.8, may be involved in the reaction to abiotic stress of germinating barley plants by mediating the intracellular transport of hydrophobic particles, such as lipids, helping to maintain homeostasis. The ns-LTP2.8 protein was selected for analysis due to its ability to transport not only linear hydrophobic molecules but also compounds with a more complex spatial structure. Moreover, ns-LTP2.8 has been qualified as a member of pathogenesis-related proteins, which makes it particularly important in relation to its high allergenic potential. This paper demonstrates for the first time the influence of various abiotic stresses acting separately as well as in their combinations on the change in the ns-LTP2.8 transcript, ns-LTP2.8 protein and total soluble protein content in the embryonal axes of germinating spring barley genotypes with different ns-LTP2.8 allelic forms and stress tolerance. Tissue localization of ns-LTP2.8 transcript as well as ns-LTP2.8 protein were also examined. Although the impact of abiotic stresses on the regulation of gene transcription and translation processes remains not fully recognized, in this work we managed to demonstrate different impact on applied stresses on the fundamental cellular processes in very little studied tissue of the embryonal axis of barley.
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Affiliation(s)
- Michał Kempa
- Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
| | | | - Piotr Ogrodowicz
- Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
| | - Tomasz Pniewski
- Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
| | - Paweł Krajewski
- Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
| | - Anetta Kuczyńska
- Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
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2
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Zhu Z, Chen X, Zhang S, Yu R, Qi C, Cheng L, Zhang X. Leveraging molecular quantitative trait loci to comprehend complex diseases/traits from the omics perspective. Hum Genet 2023; 142:1543-1560. [PMID: 37755483 DOI: 10.1007/s00439-023-02602-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 09/14/2023] [Indexed: 09/28/2023]
Abstract
Comprehending the molecular basis of quantitative genetic variation is a principal goal for complex diseases or traits. Molecular quantitative trait loci (molQTLs) have made it possible to investigate the effects of genetic variants hiding behind large-scale omics data. A deeper understanding of molQTL is urgently required in light of the multi-dimensionalization of omics data to more fully elucidate the pertinent biological mechanisms. Herein, we reviewed molQTLs with the corresponding resource from the omics perspective and further discussed the integrative strategy of GWAS-molQTL to infer their causal effects. Subsequently, we described the opportunities and challenges encountered by molQTL. The case studies showed that molQTL is essential for complex diseases and traits, whether single- or multi-omics QTLs. Overall, we highlighted the functional significance of genetic variants to employ the discovery of molQTL in complex diseases and traits.
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Affiliation(s)
- Zijun Zhu
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Xinyu Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Sainan Zhang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Rui Yu
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Changlu Qi
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Liang Cheng
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, Heilongjiang, China.
- NHC Key Laboratory of Molecular Probe and Targeted Diagnosis and Therapy, Harbin Medical University, Harbin, 150028, Heilongjiang, China.
| | - Xue Zhang
- NHC Key Laboratory of Molecular Probe and Targeted Diagnosis and Therapy, Harbin Medical University, Harbin, 150028, Heilongjiang, China
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100005, China
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Rodríguez-López M, Bordin N, Lees J, Scholes H, Hassan S, Saintain Q, Kamrad S, Orengo C, Bähler J. Broad functional profiling of fission yeast proteins using phenomics and machine learning. eLife 2023; 12:RP88229. [PMID: 37787768 PMCID: PMC10547477 DOI: 10.7554/elife.88229] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023] Open
Abstract
Many proteins remain poorly characterized even in well-studied organisms, presenting a bottleneck for research. We applied phenomics and machine-learning approaches with Schizosaccharomyces pombe for broad cues on protein functions. We assayed colony-growth phenotypes to measure the fitness of deletion mutants for 3509 non-essential genes in 131 conditions with different nutrients, drugs, and stresses. These analyses exposed phenotypes for 3492 mutants, including 124 mutants of 'priority unstudied' proteins conserved in humans, providing varied functional clues. For example, over 900 proteins were newly implicated in the resistance to oxidative stress. Phenotype-correlation networks suggested roles for poorly characterized proteins through 'guilt by association' with known proteins. For complementary functional insights, we predicted Gene Ontology (GO) terms using machine learning methods exploiting protein-network and protein-homology data (NET-FF). We obtained 56,594 high-scoring GO predictions, of which 22,060 also featured high information content. Our phenotype-correlation data and NET-FF predictions showed a strong concordance with existing PomBase GO annotations and protein networks, with integrated analyses revealing 1675 novel GO predictions for 783 genes, including 47 predictions for 23 priority unstudied proteins. Experimental validation identified new proteins involved in cellular aging, showing that these predictions and phenomics data provide a rich resource to uncover new protein functions.
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Affiliation(s)
- María Rodríguez-López
- University College London, Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentLondonUnited Kingdom
| | - Nicola Bordin
- University College London, Institute of Structural and Molecular BiologyLondonUnited Kingdom
| | - Jon Lees
- University College London, Institute of Structural and Molecular BiologyLondonUnited Kingdom
- University of BristolBristolUnited Kingdom
| | - Harry Scholes
- University College London, Institute of Structural and Molecular BiologyLondonUnited Kingdom
| | - Shaimaa Hassan
- University College London, Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentLondonUnited Kingdom
- Helwan University, Faculty of PharmacyCairoEgypt
| | - Quentin Saintain
- University College London, Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentLondonUnited Kingdom
| | - Stephan Kamrad
- University College London, Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentLondonUnited Kingdom
| | - Christine Orengo
- University College London, Institute of Structural and Molecular BiologyLondonUnited Kingdom
| | - Jürg Bähler
- University College London, Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentLondonUnited Kingdom
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Huynh TQ, Tran VN, Thai VC, Nguyen HA, Nguyen NTG, Tran MK, Nguyen TPT, Le CA, Ho LTN, Surian NU, Chen S, Nguyen TTH. Genomic alterations involved in fluoroquinolone resistance development in Staphylococcus aureus. PLoS One 2023; 18:e0287973. [PMID: 37494330 PMCID: PMC10370734 DOI: 10.1371/journal.pone.0287973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/19/2023] [Indexed: 07/28/2023] Open
Abstract
AIM Fluoroquinolone (FQ) is a potent antibiotic class. However, resistance to this class emerges quickly which hinders its application. In this study, mechanisms leading to the emergence of multidrug-resistant (MDR) Staphylococcus aureus (S. aureus) strains under FQ exposure were investigated. METHODOLOGY S. aureus ATCC 29213 was serially exposed to ciprofloxacin (CIP), ofloxacin (OFL), or levofloxacin (LEV) at sub-minimum inhibitory concentrations (sub-MICs) for 12 days to obtain S. aureus -1 strains and antibiotic-free cultured for another 10 days to obtain S. aureus-2 strains. The whole genome (WGS) and target sequencing were applied to analyze genomic alterations; and RT-qPCR was used to access the expressions of efflux-related genes, alternative sigma factors, and genes involved in FQ resistance. RESULTS A strong and irreversible increase of MICs was observed in all applied FQs (32 to 128 times) in all S. aureus-1 and remained 16 to 32 times in all S. aureus-2. WGS indicated 10 noticeable mutations occurring in all FQ-exposed S. aureus including 2 insdel mutations in SACOL0573 and rimI; a synonymous mutation in hslO; and 7 missense mutations located in an untranslated region. GrlA, was found mutated (R570H) in all S. aureus-1 and -2. Genes encoding for efflux pumps and their regulator (norA, norB, norC, and mgrA); alternative sigma factors (sigB and sigS); acetyltransferase (rimI); methicillin resistance (fmtB); and hypothetical protein BJI72_0645 were overexpressed in FQ-exposed strains. CONCLUSION The emergence of MDR S. aureus was associated with the mutations in the FQ-target sequences and the overexpression of efflux pump systems and their regulators.
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Affiliation(s)
- Thuc Quyen Huynh
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Research Center for Infectious Diseases, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Van Nhi Tran
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Van Chi Thai
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Hoang An Nguyen
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Ngoc Thuy Giang Nguyen
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Minh Khang Tran
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Thi Phuong Truc Nguyen
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Cat Anh Le
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Le Thanh Ngan Ho
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | | | - Swaine Chen
- Genome Institute of Singapore, Singapore, Singapore
| | - Thi Thu Hoai Nguyen
- School of Biotechnology, International University, Ho Chi Minh City, Vietnam
- Research Center for Infectious Diseases, International University, Ho Chi Minh City, Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
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Katz R, Attias E, Tuller T, Margaliot M. Translation in the cell under fierce competition for shared resources: a mathematical model. J R Soc Interface 2022; 19:20220535. [PMID: 36541059 PMCID: PMC9768467 DOI: 10.1098/rsif.2022.0535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
During translation, mRNAs 'compete' for shared resources. Under stress conditions, during viral infection and also in high-throughput heterologous gene expression, these resources may become scarce, e.g. the pool of free ribosomes is starved, and then the competition may have a dramatic effect on the global dynamics of translation in the cell. We model this scenario using a network that includes m ribosome flow models (RFMs) interconnected via a pool of free ribosomes. Each RFM models ribosome flow along an mRNA molecule, and the pool models the shared resource. We assume that the number of mRNAs is large, so many ribosomes are attached to the mRNAs, and the pool is starved. Our analysis shows that adding an mRNA has an intricate effect on the total protein production. The new mRNA produces new proteins, but the other mRNAs produce less proteins, as the pool that feeds these mRNAs now has a smaller abundance of ribosomes. As the number of mRNAs increases, the marginal utility of adding another mRNA diminishes, and the total protein production rate saturates to a limiting value. We demonstrate our approach using an example of insulin protein production in a cell-free system.
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Affiliation(s)
- Rami Katz
- School of Electrical Engineering, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Elad Attias
- School of Electrical Engineering, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Michael Margaliot
- School of Electrical Engineering, Tel Aviv University, Tel Aviv-Yafo, Israel
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mTOR- and LARP1-dependent regulation of TOP mRNA poly(A) tail and ribosome loading. Cell Rep 2022; 41:111548. [DOI: 10.1016/j.celrep.2022.111548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 08/30/2022] [Accepted: 09/30/2022] [Indexed: 11/20/2022] Open
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Reixachs‐Solé M, Eyras E. Uncovering the impacts of alternative splicing on the proteome with current omics techniques. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1707. [PMID: 34979593 PMCID: PMC9542554 DOI: 10.1002/wrna.1707] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022]
Abstract
The high-throughput sequencing of cellular RNAs has underscored a broad effect of isoform diversification through alternative splicing on the transcriptome. Moreover, the differential production of transcript isoforms from gene loci has been recognized as a critical mechanism in cell differentiation, organismal development, and disease. Yet, the extent of the impact of alternative splicing on protein production and cellular function remains a matter of debate. Multiple experimental and computational approaches have been developed in recent years to address this question. These studies have unveiled how molecular changes at different steps in the RNA processing pathway can lead to differences in protein production and have functional effects. New and emerging experimental technologies open exciting new opportunities to develop new methods to fully establish the connection between messenger RNA expression and protein production and to further investigate how RNA variation impacts the proteome and cell function. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing Translation > Regulation RNA Evolution and Genomics > Computational Analyses of RNA.
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Affiliation(s)
- Marina Reixachs‐Solé
- The John Curtin School of Medical ResearchAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
- EMBL Australia Partner Laboratory Network and the Australian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Eduardo Eyras
- The John Curtin School of Medical ResearchAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
- EMBL Australia Partner Laboratory Network and the Australian National UniversityCanberraAustralian Capital TerritoryAustralia
- Catalan Institution for Research and Advanced StudiesBarcelonaSpain
- Hospital del Mar Medical Research Institute (IMIM)BarcelonaSpain
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8
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Turtola M, Manav MC, Kumar A, Tudek A, Mroczek S, Krawczyk PS, Dziembowski A, Schmid M, Passmore LA, Casañal A, Jensen TH. Three-layered control of mRNA poly(A) tail synthesis in Saccharomyces cerevisiae. Genes Dev 2021; 35:1290-1303. [PMID: 34385261 PMCID: PMC8415320 DOI: 10.1101/gad.348634.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/15/2021] [Indexed: 12/13/2022]
Abstract
Biogenesis of most eukaryotic mRNAs involves the addition of an untemplated polyadenosine (pA) tail by the cleavage and polyadenylation machinery. The pA tail, and its exact length, impacts mRNA stability, nuclear export, and translation. To define how polyadenylation is controlled in S. cerevisiae, we have used an in vivo assay capable of assessing nuclear pA tail synthesis, analyzed tail length distributions by direct RNA sequencing, and reconstituted polyadenylation reactions with purified components. This revealed three control mechanisms for pA tail length. First, we found that the pA binding protein (PABP) Nab2p is the primary regulator of pA tail length. Second, when Nab2p is limiting, the nuclear pool of Pab1p, the second major PABP in yeast, controls the process. Third, when both PABPs are absent, the cleavage and polyadenylation factor (CPF) limits pA tail synthesis. Thus, Pab1p and CPF provide fail-safe mechanisms to a primary Nab2p-dependent pathway, thereby preventing uncontrolled polyadenylation and allowing mRNA export and translation.
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Affiliation(s)
- Matti Turtola
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - M Cemre Manav
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Ananthanarayanan Kumar
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Agnieszka Tudek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Seweryn Mroczek
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
- International Institute of Molecular and Cell Biology in Warsaw, 02-109 Warsaw, Poland
| | - Paweł S Krawczyk
- International Institute of Molecular and Cell Biology in Warsaw, 02-109 Warsaw, Poland
| | - Andrzej Dziembowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
- International Institute of Molecular and Cell Biology in Warsaw, 02-109 Warsaw, Poland
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Lori A Passmore
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Ana Casañal
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
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Wu B, Qiao J, Wang X, Liu M, Xu S, Sun D. Factors affecting the rapid changes of protein under short-term heat stress. BMC Genomics 2021; 22:263. [PMID: 33849452 PMCID: PMC8042900 DOI: 10.1186/s12864-021-07560-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 03/26/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Protein content determines the state of cells. The variation in protein abundance is crucial when organisms are in the early stages of heat stress, but the reasons affecting their changes are largely unknown. RESULTS We quantified 47,535 mRNAs and 3742 proteins in the filling grains of wheat in two different thermal environments. The impact of mRNA abundance and sequence features involved in protein translation and degradation on protein expression was evaluated by regression analysis. Transcription, codon usage and amino acid frequency were the main drivers of changes in protein expression under heat stress, and their combined contribution explains 58.2 and 66.4% of the protein variation at 30 and 40 °C (20 °C as control), respectively. Transcription contributes more to alterations in protein content at 40 °C (31%) than at 30 °C (6%). Furthermore, the usage of codon AAG may be closely related to the rapid alteration of proteins under heat stress. The contributions of AAG were 24 and 13% at 30 and 40 °C, respectively. CONCLUSION In this study, we analyzed the factors affecting the changes in protein expression in the early stage of heat stress and evaluated their influence.
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Affiliation(s)
- Bingjin Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Jianwen Qiao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Xiaoming Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Manshuang Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Shengbao Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Daojie Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
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González García JS, Delgado J. Stochastic microswimming model of ribosome motion on the polysome. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:9. [PMID: 33683520 DOI: 10.1140/epje/s10189-021-00011-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
In this work we assume that the ribosome propels itself during the translocation step of the translation process of protein synthesis by running a cycle of stochastically generated conformational changes involving its two subunits. This cycle includes only two experimentally found ribosome shape changes. The main result is an analytic expression for ribosome's average swimming speed on a polysome, where the ribosome is in the presence of other ribosomes. Relevant geometric parameters of ribosome deformations are calculated first by solving a deterministic problem where the ribosome runs a cycle of prescribed conformational changes. The method of reflections and pairwise additivity are used to obtain the stresses and forces needed to apply the multiparticle reciprocal theorem. Ribosome's average velocity when it runs the corresponding stochastic cycle of deformations is calculated assuming independence among the conformational cycles of different ribosomes on the polysome. The results obtained show that swimming in tandem on the polysome allows the ribosome to reach any typical subcellular speed with deformations whose amplitude is of a smaller size than when it swims alone in the fluid. Also, the flow organized by its swimming stroke becomes more determinant for its motion than random diffusion, compared to the solitary ribosome.
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Affiliation(s)
- José Santiago González García
- Seminario de Bifurcaciones y Singularidades, Departamento de Matemáticas, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, Iztapalapa, Ciudad de México, 09340, Mexico.
| | - Joaquín Delgado
- Departamento de Matemáticas, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, Iztapalapa, Ciudad de México, 09340, Mexico
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Forés-Martos J, Forte A, García-Martínez J, Pérez-Ortín JE. A Trans-Omics Comparison Reveals Common Gene Expression Strategies in Four Model Organisms and Exposes Similarities and Differences between Them. Cells 2021; 10:334. [PMID: 33562654 PMCID: PMC7914595 DOI: 10.3390/cells10020334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/01/2022] Open
Abstract
The ultimate goal of gene expression regulation is on the protein level. However, because the amounts of mRNAs and proteins are controlled by their synthesis and degradation rates, the cellular amount of a given protein can be attained by following different strategies. By studying omics data for six expression variables (mRNA and protein amounts, plus their synthesis and decay rates), we previously demonstrated the existence of common expression strategies (CESs) for functionally related genes in the yeast Saccharomyces cerevisiae. Here we extend that study to two other eukaryotes: the yeast Schizosaccharomyces pombe and cultured human HeLa cells. We also use genomic data from the model prokaryote Escherichia coli as an external reference. We show that six-variable profiles (6VPs) can be constructed for every gene and that these 6VPs are similar for genes with similar functions in all the studied organisms. The differences in 6VPs between organisms can be used to establish their phylogenetic relationships. The analysis of the correlations among the six variables supports the hypothesis that most gene expression control occurs in actively growing organisms at the transcription rate level, and that translation plays a minor role. We propose that living organisms use CESs for the genes acting on the same physiological pathways, especially for those belonging to stable macromolecular complexes, but CESs have been modeled by evolution to adapt to the specific life circumstances of each organism.
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Affiliation(s)
- Jaume Forés-Martos
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - Anabel Forte
- Departamento de Estadística e Investigación Operativa, Facultad de Matemáticas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - José García-Martínez
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - José E. Pérez-Ortín
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
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Rubio A, Ghosh S, Mülleder M, Ralser M, Mata J. Ribosome profiling reveals ribosome stalling on tryptophan codons and ribosome queuing upon oxidative stress in fission yeast. Nucleic Acids Res 2021; 49:383-399. [PMID: 33313903 PMCID: PMC7797079 DOI: 10.1093/nar/gkaa1180] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 11/13/2020] [Accepted: 11/19/2020] [Indexed: 12/11/2022] Open
Abstract
Translational control is essential in response to stress. We investigated the translational programmes launched by the fission yeast Schizosaccharomyces pombe upon five environmental stresses. We also explored the contribution of defence pathways to these programmes: The Integrated Stress Response (ISR), which regulates translation initiation, and the stress-response MAPK pathway. We performed ribosome profiling of cells subjected to each stress, in wild type cells and in cells with the defence pathways inactivated. The transcription factor Fil1, a functional homologue of the yeast Gcn4 and the mammalian Atf4 proteins, was translationally upregulated and required for the response to most stresses. Moreover, many mRNAs encoding proteins required for ribosome biogenesis were translationally downregulated. Thus, several stresses trigger a universal translational response, including reduced ribosome production and a Fil1-mediated transcriptional programme. Surprisingly, ribosomes stalled on tryptophan codons upon oxidative stress, likely due to a decrease in charged tRNA-Tryptophan. Stalling caused ribosome accumulation upstream of tryptophan codons (ribosome queuing/collisions), demonstrating that stalled ribosomes affect translation elongation by other ribosomes. Consistently, tryptophan codon stalling led to reduced translation elongation and contributed to the ISR-mediated inhibition of initiation. We show that different stresses elicit common and specific translational responses, revealing a novel role in Tryptophan-tRNA availability.
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Affiliation(s)
- Angela Rubio
- Department of Biochemistry, University of Cambridge, UK
| | - Sanjay Ghosh
- Department of Biochemistry, University of Cambridge, UK
| | - Michael Mülleder
- The Molecular Biology of Metabolism Laboratory, The Francis Crick Institute, London, UK
| | - Markus Ralser
- The Molecular Biology of Metabolism Laboratory, The Francis Crick Institute, London, UK.,Department of Biochemistry, Charité University Medicine, Berlin, Germany
| | - Juan Mata
- Department of Biochemistry, University of Cambridge, UK
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Lin L, Cao J, Du A, An Q, Chen X, Yuan S, Batool W, Shabbir A, Zhang D, Wang Z, Norvienyeku J. eIF3k Domain-Containing Protein Regulates Conidiogenesis, Appressorium Turgor, Virulence, Stress Tolerance, and Physiological and Pathogenic Development of Magnaporthe oryzae Oryzae. FRONTIERS IN PLANT SCIENCE 2021; 12:748120. [PMID: 34733303 PMCID: PMC8558559 DOI: 10.3389/fpls.2021.748120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/22/2021] [Indexed: 05/05/2023]
Abstract
The eukaryotic translation initiation factor 3 (eIF3) complex consists of essential and non-essential sub-complexes. Non-essential eIF3 complex subunits, such as eIF3e, eIF3j, eIF3k, and eIF3l, modulate stress tolerance and enhance the lifespan of Neurospora crassa and Caenorhabditis elegans. However, there is limited knowledge of the role of the non-essential eIF3 sub-complex in the pathophysiological development of plant fungal pathogens. Here, we deployed genetic and biochemical techniques to explore the influence of a hypothetical protein containing eIF3k domain in Magnaporthe oryzae Oryzae (MoOeIF3k) on reproduction, hyphae morphogenesis, stress tolerance, and pathogenesis. Also, the targeted disruption of MoOeIF3k suppressed vegetative growth and asexual sporulation in ΔMoOeif3k strains significantly. We demonstrated that MoOeIF3k promotes the initiation and development of the rice blast disease by positively regulating the mobilization and degradation of glycogen, appressorium integrity, host penetration, and colonization during host-pathogen interaction. For the first time, we demonstrated that the eIF3k subunit supports the survival of the blast fungus by suppressing vegetative growth and possibly regulating the conversions and utilization of stored cellular energy reserves under starvation conditions. We also observed that the deletion of MoOeIF3k accelerated ribosomal RNA (rRNA) generation in the ΔMoOeif3k strains with a corresponding increase in total protein output. In summary, this study unravels the pathophysiological significance of eIF3k filamentous fungi. The findings also underscored the need to systematically evaluate the individual subunits of the non-essential eIF3 sub-complex during host-pathogen interaction. Further studies are required to unravel the influence of synergetic coordination between translation and transcriptional regulatory machinery on the pathogenesis of filamentous fungi pathogens.
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Affiliation(s)
- Lili Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jiaying Cao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Anqiang Du
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qiuli An
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaomin Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shuangshuang Yuan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wajjiha Batool
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ammarah Shabbir
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Dongmei Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
- Institute of Oceanography, Minjiang University, Fuzhou, China
- Zonghua Wang,
| | - Justice Norvienyeku
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection, Hainan University, Haikou, China
- *Correspondence: Justice Norvienyeku,
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14
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Chikashige Y, Kato H, Thornton M, Pepper W, Hilgers M, Cecil A, Asano I, Yamada H, Mori C, Brunkow C, Moravek C, Urano T, Singh CR, Asano K. Gcn2 eIF2α kinase mediates combinatorial translational regulation through nucleotide motifs and uORFs in target mRNAs. Nucleic Acids Res 2020; 48:8977-8992. [PMID: 32710633 PMCID: PMC7498311 DOI: 10.1093/nar/gkaa608] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/06/2020] [Accepted: 07/24/2020] [Indexed: 12/14/2022] Open
Abstract
The protein kinase Gcn2 is a central transducer of nutritional stress signaling important for stress adaptation by normal cells and the survival of cancer cells. In response to nutrient deprivation, Gcn2 phosphorylates eIF2α, thereby repressing general translation while enhancing translation of specific mRNAs with upstream ORFs (uORFs) situated in their 5'-leader regions. Here we performed genome-wide measurements of mRNA translation during histidine starvation in fission yeast Schizosaccharomyces pombe. Polysome analyses were combined with microarray measurements to identify gene transcripts whose translation was up-regulated in response to the stress in a Gcn2-dependent manner. We determined that translation is reprogrammed to enhance RNA metabolism and chromatin regulation and repress ribosome synthesis. Interestingly, translation of intron-containing mRNAs was up-regulated. The products of the regulated genes include additional eIF2α kinase Hri2 amplifying the stress signaling and Gcn5 histone acetyl transferase and transcription factors, together altering genome-wide transcription. Unique dipeptide-coding uORFs and nucleotide motifs, such as '5'-UGA(C/G)GG-3', are found in 5' leader regions of regulated genes and shown to be responsible for translational control.
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Affiliation(s)
- Yuji Chikashige
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Hyogo 651-2492, Japan
| | - Hiroaki Kato
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane 693-8501, Japan
| | - Mackenzie Thornton
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Whitney Pepper
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Madelyn Hilgers
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Ariana Cecil
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Izumi Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Haana Yamada
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
- Department of Advanced Transdisciplinary Sciences, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Chie Mori
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Hyogo 651-2492, Japan
| | - Cheyenne Brunkow
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Carter Moravek
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Takeshi Urano
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane 693-8501, Japan
| | - Chingakham Ranjit Singh
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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15
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Slobodin B, Dikstein R. So close, no matter how far: multiple paths connecting transcription to mRNA translation in eukaryotes. EMBO Rep 2020; 21:e50799. [PMID: 32803873 PMCID: PMC7507372 DOI: 10.15252/embr.202050799] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/22/2020] [Accepted: 07/23/2020] [Indexed: 12/15/2022] Open
Abstract
Transcription of DNA into mRNA and translation of mRNA into proteins are two major processes underlying gene expression. Due to the distinct molecular mechanisms, timings, and locales of action, these processes are mainly considered to be independent. During the last two decades, however, multiple factors and elements were shown to coordinate transcription and translation, suggesting an intricate level of synchronization. This review discusses the molecular mechanisms that impact both processes in eukaryotic cells of different origins. The emerging global picture suggests evolutionarily conserved regulation and coordination between transcription and mRNA translation, indicating the importance of this phenomenon for the fine-tuning of gene expression and the adjustment to constantly changing conditions.
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Affiliation(s)
- Boris Slobodin
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovotIsrael
| | - Rivka Dikstein
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovotIsrael
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16
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Swaminathan A, Harrison PF, Preiss T, Beilharz TH. PAT-Seq: A Method for Simultaneous Quantitation of Gene Expression, Poly(A)-Site Selection and Poly(A)-Length Distribution in Yeast Transcriptomes. Methods Mol Biol 2020; 2049:141-164. [PMID: 31602610 DOI: 10.1007/978-1-4939-9736-7_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Next-generation sequencing (NGS) and its application to RNA (RNA-seq) has opened up multiple aspects of RNA processing to deep transcriptome-wide analysis at nucleotide resolution. This has been useful in delineating the transcribed areas of the genome, and in quantitation of RNA isoforms. Such isoforms can diversify the regulatory repertoire of mRNAs. For example, the 3'-end of mRNA can vary in two important ways, in the position chosen for cleavage and polyadenylation, and in the length of the poly(A)-tail. Accordingly, the step-up in resolution made possible by NGS has revealed an unexpectedly high level of alternative polyadenylation (APA). Moreover, it has massively simplified the transcriptome-wide detection of poly(A)-tail length changes. Here we present our approach to the study of 3'-end dynamics using a 3'-focused RNA-seq method called PAT-seq (for poly(A)-test sequencing). The approach records gene expression, APA, and poly(A)-tail changes between transcriptomes to reveal complex interplay between transcriptional and posttranscriptional control mechanisms.
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Affiliation(s)
- Angavai Swaminathan
- Development and Stem Cells Program, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Paul F Harrison
- Monash Bioinformatics Platform, Monash University, Melbourne, VIC, Australia
| | - Thomas Preiss
- Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.,Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Traude H Beilharz
- Development and Stem Cells Program, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia.
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17
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Kluge F, Götze M, Wahle E. Establishment of 5'-3' interactions in mRNA independent of a continuous ribose-phosphate backbone. RNA (NEW YORK, N.Y.) 2020; 26:613-628. [PMID: 32111664 PMCID: PMC7161349 DOI: 10.1261/rna.073759.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/24/2020] [Indexed: 06/10/2023]
Abstract
Functions of eukaryotic mRNAs are characterized by intramolecular interactions between their ends. We have addressed the question whether 5' and 3' ends meet by diffusion-controlled encounter "through solution" or by a mechanism involving the RNA backbone. For this purpose, we used a translation system derived from Drosophila embryos that displays two types of 5'-3' interactions: Cap-dependent translation initiation is stimulated by the poly(A) tail and inhibited by Smaug recognition elements (SREs) in the 3' UTR. Chimeric RNAs were made consisting of one RNA molecule carrying a luciferase coding sequence and a second molecule containing SREs and a poly(A) tail; the two were connected via a protein linker. The poly(A) tail stimulated translation of such chimeras even when disruption of the RNA backbone was combined with an inversion of the 5'-3' polarity between the open reading frame and poly(A) segment. Stimulation by the poly(A) tail also decreased with increasing RNA length. Both observations suggest that contacts between the poly(A) tail and the 5' end are established through solution, independently of the RNA backbone. In the same chimeric constructs, SRE-dependent inhibition of translation was also insensitive to disruption of the RNA backbone. Thus, tracking of the backbone is not involved in the repression of cap-dependent initiation. However, SRE-dependent repression was insensitive to mRNA length, suggesting that the contact between the SREs in the 3' UTR and the 5' end of the RNA might be established in a manner that differs from the contact between the poly(A) tail and the cap.
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Affiliation(s)
- Florian Kluge
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Michael Götze
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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18
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Guo Y, Peng Z, Liu J, Yuan N, Wang Z, Du J. Systematic Comparisons of Positively Selected Genes between Gossypium arboreum and Gossypium raimondii Genomes. Curr Bioinform 2019. [DOI: 10.2174/1574893614666190227151013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Studies of Positively Selected Genes (PSGs) in microorganisms and
mammals have provided insights into the dynamics of genome evolution and the genetic basis of
differences between species by using whole genome-wide scans. Systematic investigations and
comparisons of PSGs in plants, however, are still limited.
Objective:
A systematic comparison of PSGs between the genomes of two cotton species,
Gossypium arboreum (G. arboreum) and G. raimondii, will give the key answer for revealing
molecular evolutionary differences in plants.
Methods:
Genome sequences of G. arboreum and G. raimondii were compared, including Whole
Genome Duplication (WGD) events and genomic features such as gene number, gene length,
codon bias index, evolutionary rate, number of expressed genes, and retention of duplicated
copies.
Results:
Unlike the PSGs in G. raimondii, G. arboreum comprised more PSGs, smaller gene size
and fewer expressed gene. In addition, the PSGs evolved at a higher rate of synonymous
substitutions, but were subjected to lower selection pressure. The PSGs in G. arboreum were also
retained with a lower number of duplicate gene copies than G. raimondii after a single WGD event
involving Gossypium.
Conclusion:
These data indicate that PSGs in G. arboreum and G. raimondii differ not only in
Ka/Ks, but also in their evolutionary, structural, and expression properties, indicating that
divergence of G. arboreum and G. raimondii was associated with differences in PSGs in terms of
evolutionary rates, gene length, expression patterns, and WGD retention in Gossypium.
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Affiliation(s)
- Yue Guo
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Zhen Peng
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Jing Liu
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Na Yuan
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Zhen Wang
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Jianchang Du
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
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19
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Jafari Najaf Abadi MH, Shafabakhsh R, Asemi Z, Mirzaei HR, Sahebnasagh R, Mirzaei H, Hamblin MR. CFIm25 and alternative polyadenylation: Conflicting roles in cancer. Cancer Lett 2019; 459:112-121. [PMID: 31181319 DOI: 10.1016/j.canlet.2019.114430] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 12/11/2022]
Abstract
Alternative polyadenylation (APA) is now widely recognized to regulate gene expression. APA is an RNA-processing mechanism that generates distinct 3' termini on mRNAs, producing mRNA isoforms. Different factors influence the initiation and development of this process. CFIm25 (among others) is a cleavage and polyadenylation factor that plays a key role in the regulation of APA. Shortening of the 3'UTRs on mRNAs leads to enhanced cellular proliferation and tumorigenicity. One reason may be the up-regulation of growth promoting factors, such as Cyclin D1. Different studies have reported a dual role of CFIm25 in cancer (both oncogenic and tumor suppressor). microRNAs (miRNAs) may be involved in CFIm25 function as well as competing endogenous RNAs (ceRNAs). The present review focuses on the role of CFIm25 in cancer, cancer treatment, and possible involvement in other human diseases. We highlight the involvement of miRNAs and ceRNAs in the function of CFIm25 to affect gene expression. The lack of understanding of the mechanisms and regulation of CFIm25 and APA has underscored the need for further research regarding their role in cancer and other diseases.
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Affiliation(s)
| | - Rana Shafabakhsh
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran.
| | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran.
| | - Hamid Reza Mirzaei
- Department of Medical Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Roxana Sahebnasagh
- Department of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran.
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, 40 Blossom Street, Boston, MA, 02114, USA.
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20
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Ferretti MB, Karbstein K. Does functional specialization of ribosomes really exist? RNA (NEW YORK, N.Y.) 2019; 25:521-538. [PMID: 30733326 PMCID: PMC6467006 DOI: 10.1261/rna.069823.118] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
It has recently become clear that ribosomes are much more heterogeneous than previously thought, with diversity arising from rRNA sequence and modifications, ribosomal protein (RP) content and posttranslational modifications (PTMs), as well as bound nonribosomal proteins. In some cases, the existence of these diverse ribosome populations has been verified by biochemical or structural methods. Furthermore, knockout or knockdown of RPs can diversify ribosome populations, while also affecting the translation of some mRNAs (but not others) with biological consequences. However, the effects on translation arising from depletion of diverse proteins can be highly similar, suggesting that there may be a more general defect in ribosome function or stability, perhaps arising from reduced ribosome numbers. Consistently, overall reduced ribosome numbers can differentially affect subclasses of mRNAs, necessitating controls for specificity. Moreover, in order to study the functional consequences of ribosome diversity, perturbations including affinity tags and knockouts are introduced, which can also affect the outcome of the experiment. Here we review the available literature to carefully evaluate whether the published data support functional diversification, defined as diverse ribosome populations differentially affecting translation of distinct mRNA (classes). Based on these observations and the commonly observed cellular responses to perturbations in the system, we suggest a set of important controls to validate functional diversity, which should include gain-of-function assays and the demonstration of inducibility under physiological conditions.
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Affiliation(s)
- Max B Ferretti
- Department of Integrative Structural and Molecular Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Katrin Karbstein
- Department of Integrative Structural and Molecular Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida 33458, USA
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21
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Eraslan B, Wang D, Gusic M, Prokisch H, Hallström BM, Uhlén M, Asplund A, Pontén F, Wieland T, Hopf T, Hahne H, Kuster B, Gagneur J. Quantification and discovery of sequence determinants of protein-per-mRNA amount in 29 human tissues. Mol Syst Biol 2019; 15:e8513. [PMID: 30777893 PMCID: PMC6379048 DOI: 10.15252/msb.20188513] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/15/2022] Open
Abstract
Despite their importance in determining protein abundance, a comprehensive catalogue of sequence features controlling protein-to-mRNA (PTR) ratios and a quantification of their effects are still lacking. Here, we quantified PTR ratios for 11,575 proteins across 29 human tissues using matched transcriptomes and proteomes. We estimated by regression the contribution of known sequence determinants of protein synthesis and degradation in addition to 45 mRNA and 3 protein sequence motifs that we found by association testing. While PTR ratios span more than 2 orders of magnitude, our integrative model predicts PTR ratios at a median precision of 3.2-fold. A reporter assay provided functional support for two novel UTR motifs, and an immobilized mRNA affinity competition-binding assay identified motif-specific bound proteins for one motif. Moreover, our integrative model led to a new metric of codon optimality that captures the effects of codon frequency on protein synthesis and degradation. Altogether, this study shows that a large fraction of PTR ratio variation in human tissues can be predicted from sequence, and it identifies many new candidate post-transcriptional regulatory elements.
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Affiliation(s)
- Basak Eraslan
- Computational Biology, Department of Informatics, Technical University of Munich, Garching Munich, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Dongxue Wang
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | - Mirjana Gusic
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Björn M Hallström
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Mathias Uhlén
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Anna Asplund
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Frederik Pontén
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Thomas Wieland
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | - Thomas Hopf
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | | | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
- Center For Integrated Protein Science Munich (CIPSM), Munich, Germany
| | - Julien Gagneur
- Computational Biology, Department of Informatics, Technical University of Munich, Garching Munich, Germany
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22
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Kelliher CM, Foster MW, Motta FC, Deckard A, Soderblom EJ, Moseley MA, Haase SB. Layers of regulation of cell-cycle gene expression in the budding yeast Saccharomyces cerevisiae. Mol Biol Cell 2018; 29:2644-2655. [PMID: 30207828 PMCID: PMC6249835 DOI: 10.1091/mbc.e18-04-0255] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/30/2018] [Accepted: 09/04/2018] [Indexed: 11/11/2022] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, transcription factors (TFs) regulate the periodic expression of many genes during the cell cycle, including gene products required for progression through cell-cycle events. Experimental evidence coupled with quantitative models suggests that a network of interconnected TFs is capable of regulating periodic genes over the cell cycle. Importantly, these dynamical models were built on transcriptomics data and assumed that TF protein levels and activity are directly correlated with mRNA abundance. To ask whether TF transcripts match protein expression levels as cells progress through the cell cycle, we applied a multiplexed targeted mass spectrometry approach (parallel reaction monitoring) to synchronized populations of cells. We found that protein expression of many TFs and cell-cycle regulators closely followed their respective mRNA transcript dynamics in cycling wild-type cells. Discordant mRNA/protein expression dynamics was also observed for a subset of cell-cycle TFs and for proteins targeted for degradation by E3 ubiquitin ligase complexes such as SCF (Skp1/Cul1/F-box) and APC/C (anaphase-promoting complex/cyclosome). We further profiled mutant cells lacking B-type cyclin/CDK activity ( clb1-6) where oscillations in ubiquitin ligase activity, cyclin/CDKs, and cell-cycle progression are halted. We found that a number of proteins were no longer periodically degraded in clb1-6 mutants compared with wild type, highlighting the importance of posttranscriptional regulation. Finally, the TF complexes responsible for activating G1/S transcription (SBF and MBF) were more constitutively expressed at the protein level than at periodic mRNA expression levels in both wild-type and mutant cells. This comprehensive investigation of cell-cycle regulators reveals that multiple layers of regulation (transcription, protein stability, and proteasome targeting) affect protein expression dynamics during the cell cycle.
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Affiliation(s)
| | - Matthew W. Foster
- Duke Center for Genomic and Computational Biology, Proteomics and Metabolomics Shared Resource, Durham, NC 27701
| | | | | | - Erik J. Soderblom
- Duke Center for Genomic and Computational Biology, Proteomics and Metabolomics Shared Resource, Durham, NC 27701
| | - M. Arthur Moseley
- Duke Center for Genomic and Computational Biology, Proteomics and Metabolomics Shared Resource, Durham, NC 27701
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23
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Atkinson SR, Marguerat S, Bitton DA, Rodríguez-López M, Rallis C, Lemay JF, Cotobal C, Malecki M, Smialowski P, Mata J, Korber P, Bachand F, Bähler J. Long noncoding RNA repertoire and targeting by nuclear exosome, cytoplasmic exonuclease, and RNAi in fission yeast. RNA (NEW YORK, N.Y.) 2018; 24:1195-1213. [PMID: 29914874 PMCID: PMC6097657 DOI: 10.1261/rna.065524.118] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 06/14/2018] [Indexed: 05/31/2023]
Abstract
Long noncoding RNAs (lncRNAs), which are longer than 200 nucleotides but often unstable, contribute a substantial and diverse portion to pervasive noncoding transcriptomes. Most lncRNAs are poorly annotated and understood, although several play important roles in gene regulation and diseases. Here we systematically uncover and analyze lncRNAs in Schizosaccharomyces pombe. Based on RNA-seq data from twelve RNA-processing mutants and nine physiological conditions, we identify 5775 novel lncRNAs, nearly 4× the previously annotated lncRNAs. The expression of most lncRNAs becomes strongly induced under the genetic and physiological perturbations, most notably during late meiosis. Most lncRNAs are cryptic and suppressed by three RNA-processing pathways: the nuclear exosome, cytoplasmic exonuclease, and RNAi. Double-mutant analyses reveal substantial coordination and redundancy among these pathways. We classify lncRNAs by their dominant pathway into cryptic unstable transcripts (CUTs), Xrn1-sensitive unstable transcripts (XUTs), and Dicer-sensitive unstable transcripts (DUTs). XUTs and DUTs are enriched for antisense lncRNAs, while CUTs are often bidirectional and actively translated. The cytoplasmic exonuclease, along with RNAi, dampens the expression of thousands of lncRNAs and mRNAs that become induced during meiosis. Antisense lncRNA expression mostly negatively correlates with sense mRNA expression in the physiological, but not the genetic conditions. Intergenic and bidirectional lncRNAs emerge from nucleosome-depleted regions, upstream of positioned nucleosomes. Our results highlight both similarities and differences to lncRNA regulation in budding yeast. This broad survey of the lncRNA repertoire and characteristics in S. pombe, and the interwoven regulatory pathways that target lncRNAs, provides a rich framework for their further functional analyses.
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Affiliation(s)
- Sophie R Atkinson
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Samuel Marguerat
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
- MRC London Institute of Medical Sciences (LMS), London W12 0NN, United Kingdom
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Danny A Bitton
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Maria Rodríguez-López
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Charalampos Rallis
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Jean-François Lemay
- Department of Biochemistry, Sherbrooke, Université de Sherbrooke, Quebec J1H 5N4, Canada
| | - Cristina Cotobal
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Michal Malecki
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Pawel Smialowski
- LMU Munich, Biomedical Center, 82152 Planegg-Martinsried near Munich, Germany
| | - Juan Mata
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Philipp Korber
- LMU Munich, Biomedical Center, 82152 Planegg-Martinsried near Munich, Germany
| | - François Bachand
- Department of Biochemistry, Sherbrooke, Université de Sherbrooke, Quebec J1H 5N4, Canada
| | - Jürg Bähler
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
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Abstract
Ribosomopathies are a group of human disorders most commonly caused by ribosomal protein haploinsufficiency or defects in ribosome biogenesis. These conditions manifest themselves as physiological defects in specific cell and tissue types. We review current molecular models to explain ribosomopathies and attempt to reconcile the tissue specificity of these disorders with the ubiquitous requirement for ribosomes in all cells. Ribosomopathies as a group are diverse in their origins and clinical manifestations; we use the well-described Diamond-Blackfan anemia (DBA) as a specific example to highlight some common features. We discuss ribosome homeostasis as an overarching principle that governs the sensitivity of specific cells and tissue types to ribosomal protein mutations. Mathematical models and experimental insights rationalize how even subtle shifts in the availability of ribosomes, such as those created by ribosome haploinsufficiency, can drive messenger RNA-specific effects on protein expression. We discuss recently identified roles played by ribosome rescue and recycling factors in regulating ribosome homeostasis.
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Affiliation(s)
- Eric W Mills
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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25
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Jia C. Simplification of Markov chains with infinite state space and the mathematical theory of random gene expression bursts. Phys Rev E 2018; 96:032402. [PMID: 29346865 DOI: 10.1103/physreve.96.032402] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Indexed: 11/07/2022]
Abstract
Here we develop an effective approach to simplify two-time-scale Markov chains with infinite state spaces by removal of states with fast leaving rates, which improves the simplification method of finite Markov chains. We introduce the concept of fast transition paths and show that the effective transitions of the reduced chain can be represented as the superposition of the direct transitions and the indirect transitions via all the fast transition paths. Furthermore, we apply our simplification approach to the standard Markov model of single-cell stochastic gene expression and provide a mathematical theory of random gene expression bursts. We give the precise mathematical conditions for the bursting kinetics of both mRNAs and proteins. It turns out that random bursts exactly correspond to the fast transition paths of the Markov model. This helps us gain a better understanding of the physics behind the bursting kinetics as an emergent behavior from the fundamental multiscale biochemical reaction kinetics of stochastic gene expression.
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Affiliation(s)
- Chen Jia
- Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas 75080, USA
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26
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An Integrated Polysome Profiling and Ribosome Profiling Method to Investigate In Vivo Translatome. Methods Mol Biol 2018; 1712:1-18. [PMID: 29224064 DOI: 10.1007/978-1-4939-7514-3_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent advances in global translatome analysis technologies enable us to understand how translational regulation of gene expression modulates cellular functions. In this chapter, we present an integrated method to measure various aspects of translatome by polysome profiling and ribosome profiling using purified B cells. We standardized our protocols to directly compare the results from these two approaches. Parallel assessment of translatome with these two approaches can generate a comprehensive picture on how translational regulation determines protein output.
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Reconstitution of Targeted Deadenylation by the Ccr4-Not Complex and the YTH Domain Protein Mmi1. Cell Rep 2017; 17:1978-1989. [PMID: 27851962 PMCID: PMC5120349 DOI: 10.1016/j.celrep.2016.10.066] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/10/2016] [Accepted: 10/19/2016] [Indexed: 12/22/2022] Open
Abstract
Ccr4-Not is a conserved protein complex that shortens the 3' poly(A) tails of eukaryotic mRNAs to regulate transcript stability and translation into proteins. RNA-binding proteins are thought to facilitate recruitment of Ccr4-Not to certain mRNAs, but lack of an in-vitro-reconstituted system has slowed progress in understanding the mechanistic details of this specificity. Here, we generate a fully recombinant Ccr4-Not complex that removes poly(A) tails from RNA substrates. The intact complex is more active than the exonucleases alone and has an intrinsic preference for certain RNAs. The RNA-binding protein Mmi1 is highly abundant in preparations of native Ccr4-Not. We demonstrate a high-affinity interaction between recombinant Ccr4-Not and Mmi1. Using in vitro assays, we show that Mmi1 accelerates deadenylation of target RNAs. Together, our results support a model whereby both RNA-binding proteins and the sequence context of mRNAs influence deadenylation rate to regulate gene expression.
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28
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Cheng J, Maier KC, Avsec Ž, Rus P, Gagneur J. Cis-regulatory elements explain most of the mRNA stability variation across genes in yeast. RNA (NEW YORK, N.Y.) 2017; 23:1648-1659. [PMID: 28802259 PMCID: PMC5648033 DOI: 10.1261/rna.062224.117] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/31/2017] [Indexed: 05/09/2023]
Abstract
The stability of mRNA is one of the major determinants of gene expression. Although a wealth of sequence elements regulating mRNA stability has been described, their quantitative contributions to half-life are unknown. Here, we built a quantitative model for Saccharomyces cerevisiae based on functional mRNA sequence features that explains 59% of the half-life variation between genes and predicts half-life at a median relative error of 30%. The model revealed a new destabilizing 3' UTR motif, ATATTC, which we functionally validated. Codon usage proves to be the major determinant of mRNA stability. Nonetheless, single-nucleotide variations have the largest effect when occurring on 3' UTR motifs or upstream AUGs. Analyzing mRNA half-life data of 34 knockout strains showed that the effect of codon usage not only requires functional decapping and deadenylation, but also the 5'-to-3' exonuclease Xrn1, the nonsense-mediated decay genes, but not no-go decay. Altogether, this study quantitatively delineates the contributions of mRNA sequence features on stability in yeast, reveals their functional dependencies on degradation pathways, and allows accurate prediction of half-life from mRNA sequence.
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Affiliation(s)
- Jun Cheng
- Department of Informatics, Technical University of Munich, 85748 Garching, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Kerstin C Maier
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Žiga Avsec
- Department of Informatics, Technical University of Munich, 85748 Garching, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Petra Rus
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Julien Gagneur
- Department of Informatics, Technical University of Munich, 85748 Garching, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, 81377 München, Germany
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29
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Rogers DW, Böttcher MA, Traulsen A, Greig D. Ribosome reinitiation can explain length-dependent translation of messenger RNA. PLoS Comput Biol 2017; 13:e1005592. [PMID: 28598992 PMCID: PMC5482490 DOI: 10.1371/journal.pcbi.1005592] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/23/2017] [Accepted: 05/25/2017] [Indexed: 12/21/2022] Open
Abstract
Models of mRNA translation usually presume that transcripts are linear; upon reaching the end of a transcript each terminating ribosome returns to the cytoplasmic pool before initiating anew on a different transcript. A consequence of linear models is that faster translation of a given mRNA is unlikely to generate more of the encoded protein, particularly at low ribosome availability. Recent evidence indicates that eukaryotic mRNAs are circularized, potentially allowing terminating ribosomes to preferentially reinitiate on the same transcript. Here we model the effect of ribosome reinitiation on translation and show that, at high levels of reinitiation, protein synthesis rates are dominated by the time required to translate a given transcript. Our model provides a simple mechanistic explanation for many previously enigmatic features of eukaryotic translation, including the negative correlation of both ribosome densities and protein abundance on transcript length, the importance of codon usage in determining protein synthesis rates, and the negative correlation between transcript length and both codon adaptation and 5' mRNA folding energies. In contrast to linear models where translation is largely limited by initiation rates, our model reveals that all three stages of translation-initiation, elongation, and termination/reinitiation-determine protein synthesis rates even at low ribosome availability.
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Affiliation(s)
- David W. Rogers
- Experimental Evolution Research Group, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
- * E-mail:
| | - Marvin A. Böttcher
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Arne Traulsen
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Duncan Greig
- Experimental Evolution Research Group, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Department of Genetics, Evolution, and Environment, University College London, London, United Kingdom
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30
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Pastro L, Smircich P, Di Paolo A, Becco L, Duhagon MA, Sotelo-Silveira J, Garat B. Nuclear Compartmentalization Contributes to Stage-Specific Gene Expression Control in Trypanosoma cruzi. Front Cell Dev Biol 2017; 5:8. [PMID: 28243589 PMCID: PMC5303743 DOI: 10.3389/fcell.2017.00008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/25/2017] [Indexed: 12/24/2022] Open
Abstract
In the protozoan parasite Trypanosoma cruzi, as in other trypanosomatids, transcription of protein coding genes occurs in a constitutive fashion, producing large polycistronic transcription units. These units are composed of non-functionally related genes which are pervasively processed to yield each mRNA. Therefore, post-transcriptional processes are crucial to regulate gene expression. Considering that nuclear compartmentalization could contribute to gene expression regulation, we comparatively studied the nuclear, cytoplasmic and whole cell transcriptomes of the non-infective epimastigote stage of T. cruzi, using RNA-Seq. We found that the cytoplasmic transcriptome tightly correlates with the whole cell transcriptome and both equally correlate with the proteome. Nonetheless, 1,200 transcripts showed differential abundance between the nuclear and cytoplasmic fractions. For the genes with transcript content augmented in the nucleus, significant structural and compositional differences were found. The analysis of the reported epimastigote translatome and proteome, revealed scarce ribosome footprints and encoded proteins for them. Ontology analyses unveiled that many of these genes are distinctive of other parasite life-cycle stages. Finally, the relocalization of transcript abundance in the metacyclic trypomastigote infective stage was confirmed for specific genes. While gene expression is strongly dependent on transcript steady-state level, we here highlight the importance of the distribution of transcripts abundance between compartments in T. cruzi. Particularly, we show that nuclear compartmentation is playing an active role in the developmental stage determination preventing off-stage expression.
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Affiliation(s)
- Lucía Pastro
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la RepúblicaMontevideo, Uruguay; Departamento de Genética, Facultad de Medicina, Universidad de la RepúblicaMontevideo, Uruguay
| | - Pablo Smircich
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la RepúblicaMontevideo, Uruguay; Departamento de Genética, Facultad de Medicina, Universidad de la RepúblicaMontevideo, Uruguay
| | - Andrés Di Paolo
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable Montevideo, Uruguay
| | - Lorena Becco
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la República Montevideo, Uruguay
| | - María A Duhagon
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la RepúblicaMontevideo, Uruguay; Departamento de Genética, Facultad de Medicina, Universidad de la RepúblicaMontevideo, Uruguay
| | - José Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable Montevideo, Uruguay
| | - Beatriz Garat
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la República Montevideo, Uruguay
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Zafrir Z, Tuller T. Unsupervised detection of regulatory gene expression information in different genomic regions enables gene expression ranking. BMC Bioinformatics 2017; 18:77. [PMID: 28143396 PMCID: PMC5286865 DOI: 10.1186/s12859-017-1497-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/27/2017] [Indexed: 12/30/2022] Open
Abstract
Background The regulation of all gene expression steps (e.g., Transcription, RNA processing, Translation, and mRNA Degradation) is known to be primarily encoded in different parts of genes and in genomic regions in proximity to genes (e.g., promoters, untranslated regions, coding regions, introns, etc.). However, the entire gene expression codes and the genomic regions where they are encoded are still unknown. Results Here, we employ an unsupervised approach to estimate the concentration of gene expression codes in different non-coding parts of genes and transcripts, such as introns and untranslated regions, focusing on three model organisms (Escherichia coli, Saccharomyces cerevisiae, and Schizosaccharomyces pombe). Our analyses support the conjecture that regions adjacent to the beginning and end of ORFs and the beginning and end of introns tend to include higher concentration of gene expression information relatively to regions further away. In addition, we report the exact regions with elevated concentration of gene expression codes. Furthermore, we demonstrate that the concentration of these codes in different genetic regions is correlated with the expression levels of the corresponding genes, and with splicing efficiency measurements and meiotic stage gene expression measurements in S. cerevisiae. Conclusion We suggest that these discoveries improve our understanding of gene expression regulation and evolution; they can also be used for developing improved models of genome/gene evolution and for engineering gene expression in various biotechnological and synthetic biology applications. Electronic supplementary material The online version of this article (doi:10.1186/s12859-017-1497-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zohar Zafrir
- Department of Biomedical Engineering, Tel Aviv University, P.O. Box 39040, Tel Aviv, 6997801, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, Tel Aviv University, P.O. Box 39040, Tel Aviv, 6997801, Israel. .,Sagol School of Neuroscience, Tel Aviv University, P.O. Box 39040, Tel Aviv, 6997801, Israel.
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32
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Analysis of Ribosome-Associated mRNAs in Rice Reveals the Importance of Transcript Size and GC Content in Translation. G3-GENES GENOMES GENETICS 2017; 7:203-219. [PMID: 27852012 PMCID: PMC5217110 DOI: 10.1534/g3.116.036020] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Gene expression is controlled at transcriptional and post-transcriptional levels including decoding of messenger RNA (mRNA) into polypeptides via ribosome-mediated translation. Translational regulation has been intensively studied in the model dicot plant Arabidopsis thaliana, and in this study, we assessed the translational status [proportion of steady-state mRNA associated with ribosomes] of mRNAs by Translating Ribosome Affinity Purification followed by mRNA-sequencing (TRAP-seq) in rice (Oryza sativa), a model monocot plant and the most important food crop. A survey of three tissues found that most transcribed rice genes are translated whereas few transposable elements are associated with ribosomes. Genes with short and GC-rich coding regions are overrepresented in ribosome-associated mRNAs, suggesting that the GC-richness characteristic of coding sequences in grasses may be an adaptation that favors efficient translation. Transcripts with retained introns and extended 5′ untranslated regions are underrepresented on ribosomes, and rice genes belonging to different evolutionary lineages exhibited differential enrichment on the ribosomes that was associated with GC content. Genes involved in photosynthesis and stress responses are preferentially associated with ribosomes, whereas genes in epigenetic regulation pathways are the least enriched on ribosomes. Such variation is more dramatic in rice than that in Arabidopsis and is correlated with the wide variation of GC content of transcripts in rice. Taken together, variation in the translation status of individual transcripts reflects important mechanisms of gene regulation, which may have a role in evolution and diversification.
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33
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Harigaya Y, Parker R. Analysis of the association between codon optimality and mRNA stability in Schizosaccharomyces pombe. BMC Genomics 2016; 17:895. [PMID: 27825301 PMCID: PMC5101800 DOI: 10.1186/s12864-016-3237-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 11/01/2016] [Indexed: 02/06/2023] Open
Abstract
Background Recent experiments have shown that codon optimality is a major determinant of mRNA stability in Saccharomyces cerevisiae and that this phenomenon may be conserved in Escherichia coli and some metazoans, although work in Neurospora crassa is not consistent with this model. Results We examined the association between codon optimality and mRNA stability in the fission yeast Schizosaccharomyces pombe. Our analysis revealed the following points. First, we observe a genome-wide association between codon optimality and mRNA stability also in S. pombe, suggesting evolutionary conservation of the phenomenon. Second, in both S. pombe and S. cerevisiae, mRNA synthesis rates are also correlated at the genome-wide analysis with codon optimality, suggesting that the long-appreciated association between codon optimality and mRNA abundance is due to regulation of both mRNA synthesis and degradation. However, when we examined correlation of codon optimality and either mRNA half-lives or synthesis rates controlling for mRNA abundance, codon optimality was still positively correlated with mRNA half-lives in S. cerevisiae, but the association was no longer significant for mRNA half-lives in S. pombe or for synthesis rates in either organism. This illustrates how only the pairwise analysis of multiple correlating variables may limit these types of analyses. Finally, in S. pombe, codon optimality is associated with known DNA/RNA sequence motifs that are associated with mRNA production/stability, suggesting these two features have been under similar selective pressures for optimal gene expression. Conclusions Consistent with the emerging body of studies, this study suggests that the association between codon optimality and mRNA stability may be a broadly conserved phenomenon. It also suggests that the association can be explained at least in part by independent adaptations of codon optimality and other transcript features for elevated expression during evolution. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3237-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuriko Harigaya
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, 80303, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, 80303, USA.
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, 80303, USA.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
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Pang M, Bai XY, Li Y, Bai JZ, Yuan LR, Ren SA, Hu XY, Zhang XR, Yu BF, Guo R, Wang HL. Label-free LC-MS/MS shotgun proteomics to investigate the anti-inflammatory effect of rCC16. Mol Med Rep 2016; 14:4496-4504. [PMID: 27748820 PMCID: PMC5101986 DOI: 10.3892/mmr.2016.5841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 08/18/2016] [Indexed: 12/30/2022] Open
Abstract
Clara cell protein (CC16) is an anti-inflammatory protein, which is expressed in the airway epithelium. It is involved in the development of airway inflammatory diseases, including chronic obstructive pulmonary disease and asthma. However, the exact molecular mechanism underlying its anti‑inflammatory action remains to be fully elucidated. The aim of the present study was to define the protein profiles of the anti‑inflammatory effect of CC16 in lipopolysaccharide (LPS)‑treated rat tracheal epithelial (RTE) cells using shotgun proteomics. Protein extracts were obtained from control RTE cells, RTE cells treated with LPS and RTE cells treated with LPS and recombinant CC16 (rCC16). Subsequent label‑free quantification and bioinformatics analyses identified 12 proteins that were differentially expressed in the three treatment groups as a cluster of five distinct groups according to their molecular functions. Five of the twelve proteins were revealed to be associated with the cytoskeleton: Matrix metalloproteinase‑9, myosin heavy chain 10, actin‑related protein‑3 homolog, elongation factor 1‑α‑1 (EF‑1‑α‑1), and acidic ribosomal phosphoprotein P0. Five of the twelve proteins were associated with cellular proliferation: DNA‑dependent protein kinase catalytic subunit, EF‑1‑α‑1, tyrosine 3‑monooxygenase, caspase recruitment domain (CARD) protein 12 and adenosylhomocysteinase (SAHH) 3. Three proteins were associated with gene regulation: EF‑1‑α‑1, SAHH 3 and acidic ribosomal phosphoprotein P0. Three proteins were associated with inflammation: Tyrosine 3‑monooxygenase, CARD protein 12 and statin‑related protein. ATPase (H+‑transporting, V1 subunit A, isoform 1) was revealed to be associated with energy metabolism, and uridine diphosphate glycosyltransferase 1 family polypeptide A8 with drug metabolism and detoxification. The identified proteins were further validated using reverse transcription‑quantitative polymerase chain reaction. These protein profiles, and their interacting protein network, may facilitate the elucidation of the molecular mechanisms underlying the anti‑inflammatory effects of CC16.
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Affiliation(s)
- Min Pang
- Respiratory Department, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Xin-Yan Bai
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Yan Li
- Fan‑Xing Biological Technology Co., Ltd., Beijing 010000, P.R. China
| | - Ji-Zhong Bai
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Li-Rong Yuan
- Respiratory Department, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Shou-An Ren
- Respiratory Department, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Xiao-Yun Hu
- Respiratory Department, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Xin-Ri Zhang
- Respiratory Department, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Bao-Feng Yu
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Rui Guo
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Hai-Long Wang
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
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35
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Zur H, Tuller T. Predictive biophysical modeling and understanding of the dynamics of mRNA translation and its evolution. Nucleic Acids Res 2016; 44:9031-9049. [PMID: 27591251 PMCID: PMC5100582 DOI: 10.1093/nar/gkw764] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/19/2016] [Indexed: 12/12/2022] Open
Abstract
mRNA translation is the fundamental process of decoding the information encoded in mRNA molecules by the ribosome for the synthesis of proteins. The centrality of this process in various biomedical disciplines such as cell biology, evolution and biotechnology, encouraged the development of dozens of mathematical and computational models of translation in recent years. These models aimed at capturing various biophysical aspects of the process. The objective of this review is to survey these models, focusing on those based and/or validated on real large-scale genomic data. We consider aspects such as the complexity of the models, the biophysical aspects they regard and the predictions they may provide. Furthermore, we survey the central systems biology discoveries reported on their basis. This review demonstrates the fundamental advantages of employing computational biophysical translation models in general, and discusses the relative advantages of the different approaches and the challenges in the field.
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Affiliation(s)
- Hadas Zur
- Department of Biomedical Engineering, the Engineering Faculty, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, the Engineering Faculty, Tel Aviv University, Tel-Aviv 69978, Israel
- The Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv 69978, Israel
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Rijal K, Maraia RJ. Active Center Control of Termination by RNA Polymerase III and tRNA Gene Transcription Levels In Vivo. PLoS Genet 2016; 12:e1006253. [PMID: 27518095 PMCID: PMC4982682 DOI: 10.1371/journal.pgen.1006253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/21/2016] [Indexed: 01/18/2023] Open
Abstract
The ability of RNA polymerase (RNAP) III to efficiently recycle from termination to reinitiation is critical for abundant tRNA production during cellular proliferation, development and cancer. Yet understanding of the unique termination mechanisms used by RNAP III is incomplete, as is its link to high transcription output. We used two tRNA-mediated suppression systems to screen for Rpc1 mutants with gain- and loss- of termination phenotypes in S. pombe. 122 point mutation mutants were mapped to a recently solved 3.9 Å structure of yeast RNAP III elongation complex (EC); they cluster in the active center bridge helix and trigger loop, as well as the pore and funnel, the latter of which indicate involvement of the RNA cleavage domain of the C11 subunit in termination. Purified RNAP III from a readthrough (RT) mutant exhibits increased elongation rate. The data strongly support a kinetic coupling model in which elongation rate is inversely related to termination efficiency. The mutants exhibit good correlations of terminator RT in vitro and in vivo, and surprisingly, amounts of transcription in vivo. Because assessing in vivo transcription can be confounded by various parameters, we used a tRNA reporter with a processing defect and a strong terminator. By ruling out differences in RNA decay rates, the data indicate that mutants with the RT phenotype synthesize more RNA than wild type cells, and than can be accounted for by their increased elongation rate. Finally, increased activity by the mutants appears unrelated to the RNAP III repressor, Maf1. The results show that the mobile elements of the RNAP III active center, including C11, are key determinants of termination, and that some of the mutations activate RNAP III for overall transcription. Similar mutations in spontaneous cancer suggest this as an unforeseen mechanism of RNAP III activation in disease.
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Affiliation(s)
- Keshab Rijal
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Richard J. Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
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Zur H, Aviner R, Tuller T. Complementary Post Transcriptional Regulatory Information is Detected by PUNCH-P and Ribosome Profiling. Sci Rep 2016; 6:21635. [PMID: 26898226 PMCID: PMC4761937 DOI: 10.1038/srep21635] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 01/27/2016] [Indexed: 01/09/2023] Open
Abstract
Two novel approaches were recently suggested for genome-wide identification of protein aspects synthesized at a given time. Ribo-Seq is based on sequencing all the ribosome protected mRNA fragments in a cell, while PUNCH-P is based on mass-spectrometric analysis of only newly synthesized proteins. Here we describe the first Ribo-Seq/PUNCH-P comparison via the analysis of mammalian cells during the cell-cycle for detecting relevant differentially expressed genes between G1 and M phase. Our analyses suggest that the two approaches significantly overlap with each other. However, we demonstrate that there are biologically meaningful proteins/genes that can be detected to be post-transcriptionally regulated during the mammalian cell cycle only by each of the approaches, or their consolidation. Such gene sets are enriched with proteins known to be related to intra-cellular signalling pathways such as central cell cycle processes, central gene expression regulation processes, processes related to chromosome segregation, DNA damage, and replication, that are post-transcriptionally regulated during the mammalian cell cycle. Moreover, we show that combining the approaches better predicts steady state changes in protein abundance. The results reported here support the conjecture that for gaining a full post-transcriptional regulation picture one should integrate the two approaches.
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Affiliation(s)
- Hadas Zur
- Department of Biomedical Engineering, the Engineering Faculty, Tel Aviv University, Israel
| | - Ranen Aviner
- Department of Cell Research and Immunology, Tel Aviv University, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, the Engineering Faculty, Tel Aviv University, Israel.,The Sagol School of Neuroscience, Tel Aviv University, Israel
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Bitton DA, Schubert F, Dey S, Okoniewski M, Smith GC, Khadayate S, Pancaldi V, Wood V, Bähler J. AnGeLi: A Tool for the Analysis of Gene Lists from Fission Yeast. Front Genet 2015; 6:330. [PMID: 26635866 PMCID: PMC4644808 DOI: 10.3389/fgene.2015.00330] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/30/2015] [Indexed: 01/08/2023] Open
Abstract
Genome-wide assays and screens typically result in large lists of genes or proteins. Enrichments of functional or other biological properties within such lists can provide valuable insights and testable hypotheses. To systematically detect these enrichments can be challenging and time-consuming, because relevant data to compare against query gene lists are spread over many different sources. We have developed AnGeLi (Analysis of Gene Lists), an intuitive, integrated web-tool for comprehensive and customized interrogation of gene lists from the fission yeast, Schizosaccharomyces pombe. AnGeLi searches for significant enrichments among multiple qualitative and quantitative information sources, including gene and phenotype ontologies, genetic and protein interactions, numerous features of genes, transcripts, translation, and proteins such as copy numbers, chromosomal positions, genetic diversity, RNA polymerase II and ribosome occupancy, localization, conservation, half-lives, domains, and molecular weight among others, as well as diverse sets of genes that are co-regulated or lead to the same phenotypes when mutated. AnGeLi uses robust statistics which can be tailored to specific needs. It also provides the option to upload user-defined gene sets to compare against the query list. Through an integrated data submission form, AnGeLi encourages the community to contribute additional curated gene lists to further increase the usefulness of this resource and to get the most from the ever increasing large-scale experiments. AnGeLi offers a rigorous yet flexible statistical analysis platform for rich insights into functional enrichments and biological context for query gene lists, thus providing a powerful exploratory tool through which S. pombe researchers can uncover fresh perspectives and unexpected connections from genomic data. AnGeLi is freely available at: www.bahlerlab.info/AnGeLi.
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Affiliation(s)
- Danny A. Bitton
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
| | - Falk Schubert
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
| | - Shoumit Dey
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
| | | | - Graeme C. Smith
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
| | - Sanjay Khadayate
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
| | - Vera Pancaldi
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
| | - Valerie Wood
- Cambridge Systems Biology and Department of Biochemistry, University of CambridgeCambridge, UK
| | - Jürg Bähler
- Research Department of Genetics, Evolution and Environment – UCL Genetics Institute, University College LondonLondon, UK
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Zhang Z, Presgraves DC. DrosophilaX-Linked Genes Have Lower Translation Rates than Autosomal Genes. Mol Biol Evol 2015; 33:413-28. [DOI: 10.1093/molbev/msv227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 10/12/2015] [Indexed: 12/13/2022] Open
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Genome-Wide Analysis of PAPS1-Dependent Polyadenylation Identifies Novel Roles for Functionally Specialized Poly(A) Polymerases in Arabidopsis thaliana. PLoS Genet 2015; 11:e1005474. [PMID: 26305463 PMCID: PMC4549238 DOI: 10.1371/journal.pgen.1005474] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 07/28/2015] [Indexed: 11/29/2022] Open
Abstract
The poly(A) tail at 3’ ends of eukaryotic mRNAs promotes their nuclear export, stability and translational efficiency, and changes in its length can strongly impact gene expression. The Arabidopsis thaliana genome encodes three canonical nuclear poly(A) polymerases, PAPS1, PAPS2 and PAPS4. As shown by their different mutant phenotypes, these three isoforms are functionally specialized, with PAPS1 modifying organ growth and suppressing a constitutive immune response. However, the molecular basis of this specialization is largely unknown. Here, we have estimated poly(A)-tail lengths on a transcriptome-wide scale in wild-type and paps1 mutants. This identified categories of genes as particularly strongly affected in paps1 mutants, including genes encoding ribosomal proteins, cell-division factors and major carbohydrate-metabolic proteins. We experimentally verified two novel functions of PAPS1 in ribosome biogenesis and redox homoeostasis that were predicted based on the analysis of poly(A)-tail length changes in paps1 mutants. When overlaying the PAPS1-dependent effects observed here with coexpression analysis based on independent microarray data, the two clusters of transcripts that are most closely coexpressed with PAPS1 show the strongest change in poly(A)-tail length and transcript abundance in paps1 mutants in our analysis. This suggests that their coexpression reflects at least partly the preferential polyadenylation of these transcripts by PAPS1 versus the other two poly(A)-polymerase isoforms. Thus, transcriptome-wide analysis of poly(A)-tail lengths identifies novel biological functions and likely target transcripts for polyadenylation by PAPS1. Data integration with large-scale co-expression data suggests that changes in the relative activities of the isoforms are used as an endogenous mechanism to co-ordinately modulate plant gene expression. The poly(A) tail of eukaryotic mRNAs promotes export from the nucleus, translation in the cytoplasm and stability of the mRNA, and changes in poly(A)-tail length can strongly impact on gene expression. The Arabidopsis thaliana genome encodes three nuclear canonical poly(A) polymerases (PAPS1, PAPS2, PAPS4) that fulfill different functions, presumably by preferentially polyadenylating certain subpopulations of pre-mRNAs. Here, we use a fractionation-based technique to assess the transcriptome-wide impact of reduced PAPS1 activity and identify functional classes of transcripts that are particularly sensitive to reduced PAPS1 activity. Analysis of these transcripts identifies two novel biological functions for PAPS1 in ribosome biogenesis and in redox homeostasis that we confirm experimentally. By overlaying our results with information about genome-wide co-expression, we demonstrate that genes co-expressed with PAPS1 are the most strongly affected in terms of poly(A)-tail length and total-abundance changes in the paps1 mutants. This provides strong evidence that the co-expression of these genes with PAPS1 that is seen across thousands of microarrays is at least partly caused by altered activity of the PAPS1 isoform, suggesting that the plant indeed uses modulation of the balance of isoform activities to coordinately regulate the expression of groups of genes.
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Harrison PF, Powell DR, Clancy JL, Preiss T, Boag PR, Traven A, Seemann T, Beilharz TH. PAT-seq: a method to study the integration of 3'-UTR dynamics with gene expression in the eukaryotic transcriptome. RNA (NEW YORK, N.Y.) 2015; 21:1502-10. [PMID: 26092945 PMCID: PMC4509939 DOI: 10.1261/rna.048355.114] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 04/20/2015] [Indexed: 05/21/2023]
Abstract
A major objective of systems biology is to quantitatively integrate multiple parameters from genome-wide measurements. To integrate gene expression with dynamics in poly(A) tail length and adenylation site, we developed a targeted next-generation sequencing approach, Poly(A)-Test RNA-sequencing. PAT-seq returns (i) digital gene expression, (ii) polyadenylation site/s, and (iii) the polyadenylation-state within and between eukaryotic transcriptomes. PAT-seq differs from previous 3' focused RNA-seq methods in that it depends strictly on 3' adenylation within total RNA samples and that the full-native poly(A) tail is included in the sequencing libraries. Here, total RNA samples from budding yeast cells were analyzed to identify the intersect between adenylation state and gene expression in response to loss of the major cytoplasmic deadenylase Ccr4. Furthermore, concordant changes to gene expression and adenylation-state were demonstrated in the classic Crabtree-Warburg metabolic shift. Because all polyadenylated RNA is interrogated by the approach, alternative adenylation sites, noncoding RNA and RNA-decay intermediates were also identified. Most important, the PAT-seq approach uses standard sequencing procedures, supports significant multiplexing, and thus replication and rigorous statistical analyses can for the first time be brought to the measure of 3'-UTR dynamics genome wide.
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Affiliation(s)
- Paul F Harrison
- Victorian Bioinformatics Consortium, Monash University, Clayton 3800, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton 3053, Australia Monash Bioinformatics Platform, Monash University, Clayton 3800, Australia
| | - David R Powell
- Victorian Bioinformatics Consortium, Monash University, Clayton 3800, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton 3053, Australia Monash Bioinformatics Platform, Monash University, Clayton 3800, Australia
| | - Jennifer L Clancy
- EMBL-Australia Collaborating Laboratory, Genome Biology Department, The John Curtin School of Medical Research (JCSMR), The Australian National University, Acton (Canberra) 2601, Australian Capital Territory, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Laboratory, Genome Biology Department, The John Curtin School of Medical Research (JCSMR), The Australian National University, Acton (Canberra) 2601, Australian Capital Territory, Australia Victor Chang Cardiac Research Institute, Darlinghurst (Sydney), New South Wales 2010, Australia
| | - Peter R Boag
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
| | - Torsten Seemann
- Victorian Bioinformatics Consortium, Monash University, Clayton 3800, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton 3053, Australia
| | - Traude H Beilharz
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
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42
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Condensin targets and reduces unwound DNA structures associated with transcription in mitotic chromosome condensation. Nat Commun 2015. [PMID: 26204128 PMCID: PMC4525155 DOI: 10.1038/ncomms8815] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Chromosome condensation is a hallmark of mitosis in eukaryotes and is a prerequisite for faithful segregation of genetic material to daughter cells. Here we show that condensin, which is essential for assembling condensed chromosomes, helps to preclude the detrimental effects of gene transcription on mitotic condensation. ChIP-seq profiling reveals that the fission yeast condensin preferentially binds to active protein-coding genes in a transcription-dependent manner during mitosis. Pharmacological and genetic attenuation of transcription largely rescue bulk chromosome segregation defects observed in condensin mutants. We also demonstrate that condensin is associated with and reduces unwound DNA segments generated by transcription, providing a direct link between an in vitro activity of condensin and its in vivo function. The human condensin isoform condensin I also binds to unwound DNA regions at the transcription start sites of active genes, implying that our findings uncover a fundamental feature of condensin complexes. Chromosome condensation is a prerequisite for faithful segregation of chromosomes to daughter cells. Here, the authors show that the condensin complex binds to protein-coding genes in a transcription-dependent manner during condensation, and reduces unwound DNA segments generated by transcription.
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43
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Basbouss-Serhal I, Soubigou-Taconnat L, Bailly C, Leymarie J. Germination Potential of Dormant and Nondormant Arabidopsis Seeds Is Driven by Distinct Recruitment of Messenger RNAs to Polysomes. PLANT PHYSIOLOGY 2015; 168:1049-65. [PMID: 26019300 PMCID: PMC4741348 DOI: 10.1104/pp.15.00510] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/21/2015] [Indexed: 05/19/2023]
Abstract
Dormancy is a complex evolutionary trait that temporally prevents seed germination, thus allowing seedling growth at a favorable season. High-throughput analyses of transcriptomes have led to significant progress in understanding the molecular regulation of this process, but the role of posttranscriptional mechanisms has received little attention. In this work, we have studied the dynamics of messenger RNA association with polysomes and compared the transcriptome with the translatome in dormant and nondormant seeds of Arabidopsis (Arabidopsis thaliana) during their imbibition at 25 °C in darkness, a temperature preventing germination of dormant seeds only. DNA microarray analysis revealed that 4,670 and 7,028 transcripts were differentially abundant in dormant and nondormant seeds in the transcriptome and the translatome, respectively. We show that there is no correlation between transcriptome and translatome and that germination regulation is also largely translational, implying a selective and dynamic recruitment of messenger RNAs to polysomes in both dormant and nondormant seeds. The study of 5' untranslated region features revealed that GC content and the number of upstream open reading frames could play a role in selective translation occurring during germination. Gene Ontology clustering showed that the functions of polysome-associated transcripts differed between dormant and nondormant seeds and revealed actors in seed dormancy and germination. In conclusion, our results demonstrate the essential role of selective polysome loading in this biological process.
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Affiliation(s)
- Isabelle Basbouss-Serhal
- Sorbonne Universités, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, F-75005 Paris, France (I.B.-S., C.B., J.L.);Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, Biologie du Développement, F-75005 Paris, France (I.B.-S., C.B., J.L.); andUnité de Recherche en Génomique Végétale, Unité Mixte de Recherche 1165, Institut National de la Recherche Agronomique, 91057 Evry, France (L.S.-T.)
| | - Ludivine Soubigou-Taconnat
- Sorbonne Universités, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, F-75005 Paris, France (I.B.-S., C.B., J.L.);Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, Biologie du Développement, F-75005 Paris, France (I.B.-S., C.B., J.L.); andUnité de Recherche en Génomique Végétale, Unité Mixte de Recherche 1165, Institut National de la Recherche Agronomique, 91057 Evry, France (L.S.-T.)
| | - Christophe Bailly
- Sorbonne Universités, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, F-75005 Paris, France (I.B.-S., C.B., J.L.);Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, Biologie du Développement, F-75005 Paris, France (I.B.-S., C.B., J.L.); andUnité de Recherche en Génomique Végétale, Unité Mixte de Recherche 1165, Institut National de la Recherche Agronomique, 91057 Evry, France (L.S.-T.)
| | - Juliette Leymarie
- Sorbonne Universités, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, F-75005 Paris, France (I.B.-S., C.B., J.L.);Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Unité Mixte de Recherche 7622, Biologie du Développement, F-75005 Paris, France (I.B.-S., C.B., J.L.); andUnité de Recherche en Génomique Végétale, Unité Mixte de Recherche 1165, Institut National de la Recherche Agronomique, 91057 Evry, France (L.S.-T.)
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Suzuki Y, Arae T, Green PJ, Yamaguchi J, Chiba Y. AtCCR4a and AtCCR4b are Involved in Determining the Poly(A) Length of Granule-bound starch synthase 1 Transcript and Modulating Sucrose and Starch Metabolism in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2015; 56:863-74. [PMID: 25630334 DOI: 10.1093/pcp/pcv012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 01/21/2015] [Indexed: 05/11/2023]
Abstract
Removing the poly(A) tail is the first and rate-limiting step of mRNA degradation and apparently an effective step not only for modulating mRNA stability but also for translation of many eukaryotic transcripts. Carbon catabolite repressor 4 (CCR4) has been identified as a major cytoplasmic deadenylase in Saccharomyces cerevisiae. The Arabidopsis thaliana homologs of the yeast CCR4, AtCCR4a and AtCCR4b, were identified by sequence-based analysis; however, their role and physiological significance in plants remain to be elucidated. In this study, we revealed that AtCCR4a and AtCCR4b are localized to cytoplasmic mRNA processing bodies, which are specific granules consisting of many enzymes involved in mRNA turnover. Double mutants of AtCCR4a and AtCCR4b exhibited tolerance to sucrose application but not to glucose. The levels of sucrose in the seedlings of the atccr4a/4b double mutants were reduced, whereas no difference was observed in glucose levels. Further, amylose levels were slightly but significantly increased in the atccr4a/4b double mutants. Consistent with this observation, we found that the transcript encoding granule-bound starch synthase 1 (GBSS1), which is responsible for amylose synthesis, is accumulated to a higher level in the atccr4a/4b double mutant plants than in the control plants. Moreover, we revealed that GBSS1 has a longer poly(A) tail in the double mutant than in the control plant, suggesting that AtCCR4a and AtCCR4b can influence the poly(A) length of transcripts related to starch metabolism. Our results collectively suggested that AtCCR4a and AtCCR4b are involved in sucrose and starch metabolism in A. thaliana.
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Affiliation(s)
- Yuya Suzuki
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Toshihiro Arae
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Pamela J Green
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Junji Yamaguchi
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Yukako Chiba
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan JST PRESTO, Kawaguchi, 332-0012 Japan
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45
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Oda A, Takemata N, Hirata Y, Miyoshi T, Suzuki Y, Sugano S, Ohta K. Dynamic transition of transcription and chromatin landscape during fission yeast adaptation to glucose starvation. Genes Cells 2015; 20:392-407. [DOI: 10.1111/gtc.12229] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/18/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Arisa Oda
- Department of Biophysics and Biochemistry Graduate School of Science The University of Tokyo Hongo Tokyo 113‐0033 Japan
| | - Naomichi Takemata
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Meguro‐ku Tokyo 153‐8902 Japan
| | - Yoshito Hirata
- Institute of Industrial Science The University of Tokyo Meguro‐ku Tokyo 153‐8505 Japan
| | - Tomoichiro Miyoshi
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Meguro‐ku Tokyo 153‐8902 Japan
| | - Yutaka Suzuki
- Department of Medical Genome Sciences Graduate School of Frontier Sciences The University of Tokyo Kashiwa Chiba 277‐8561 Japan
| | - Sumio Sugano
- Department of Medical Genome Sciences Graduate School of Frontier Sciences The University of Tokyo Kashiwa Chiba 277‐8561 Japan
| | - Kunihiro Ohta
- Department of Biophysics and Biochemistry Graduate School of Science The University of Tokyo Hongo Tokyo 113‐0033 Japan
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Meguro‐ku Tokyo 153‐8902 Japan
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46
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Pop C, Rouskin S, Ingolia NT, Han L, Phizicky EM, Weissman JS, Koller D. Causal signals between codon bias, mRNA structure, and the efficiency of translation and elongation. Mol Syst Biol 2014; 10:770. [PMID: 25538139 PMCID: PMC4300493 DOI: 10.15252/msb.20145524] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Ribosome profiling data report on the distribution of translating ribosomes, at steady-state, with codon-level resolution. We present a robust method to extract codon translation rates and protein synthesis rates from these data, and identify causal features associated with elongation and translation efficiency in physiological conditions in yeast. We show that neither elongation rate nor translational efficiency is improved by experimental manipulation of the abundance or body sequence of the rare AGG tRNA. Deletion of three of the four copies of the heavily used ACA tRNA shows a modest efficiency decrease that could be explained by other rate-reducing signals at gene start. This suggests that correlation between codon bias and efficiency arises as selection for codons to utilize translation machinery efficiently in highly translated genes. We also show a correlation between efficiency and RNA structure calculated both computationally and from recent structure probing data, as well as the Kozak initiation motif, which may comprise a mechanism to regulate initiation.
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Affiliation(s)
- Cristina Pop
- Computer Science Department, Stanford University, Stanford, CA, USA
| | - Silvi Rouskin
- Department of Cellular and Molecular Pharmacology, California Institute of Quantitative Biology, Center for RNA Systems Biology, Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Nicholas T Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Lu Han
- School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY, USA
| | - Eric M Phizicky
- School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, California Institute of Quantitative Biology, Center for RNA Systems Biology, Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Daphne Koller
- Computer Science Department, Stanford University, Stanford, CA, USA
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47
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King HA, Gerber AP. Translatome profiling: methods for genome-scale analysis of mRNA translation. Brief Funct Genomics 2014; 15:22-31. [PMID: 25380596 DOI: 10.1093/bfgp/elu045] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During the past decade, there has been a rapidly increased appreciation of the role of translation as a key regulatory node in gene expression. Thereby, the development of methods to infer the translatome, which refers to the entirety of mRNAs associated with ribosomes for protein synthesis, has facilitated the discovery of new principles and mechanisms of translation and expanded our view of the underlying logic of protein synthesis. Here, we review the three main methodologies for translatome analysis, and we highlight some of the recent discoveries made using each technique. We first discuss polysomal profiling, a classical technique that involves the separation of mRNAs depending on the number of bound ribosomes using a sucrose gradient, and which has been combined with global analysis tools such as DNA microarrays or high-throughput RNA sequencing to identify the RNAs in polysomal fractions. We then introduce ribosomal profiling, a recently established technique that enables the mapping of ribosomes along mRNAs at near-nucleotide resolution on a global scale. We finally refer to ribosome affinity purification techniques that are based on the cell-type-specific expression of tagged ribosomal proteins, allowing the capture of translatomes from specialized cells in organisms. We discuss the advantages and disadvantages of these three main techniques in the pursuit of defining the translatome, and we speculate about future developments.
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48
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Hrit J, Raynard N, Van Etten J, Sankar K, Petterson A, Goldstrohm AC. In vitro analysis of RNA degradation catalyzed by deadenylase enzymes. Methods Mol Biol 2014; 1125:325-39. [PMID: 24590800 DOI: 10.1007/978-1-62703-971-0_26] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this chapter, we describe a method for purification and analysis of the enzymatic activity of deadenylase enzymes. Nearly all eukaryotic messenger RNAs are modified at the 3' end by the addition of an adenosine polymer: the poly-adenosine tail. The poly(A) tail plays a central role in protein expression and mRNA fate. The poly(A) tail promotes translation of the mRNA. Shortening of the poly(A) tail, referred to as deadenylation, reduces protein synthesis and initiates destruction of the mRNA. A specialized class of exoribonucleases, called deadenylase enzymes, carries out this process. Deadenylases are found throughout eukarya, but their functions remain largely unexplored. We present a detailed protocol to analyze deadenylase activity in vitro. First, recombinant deadenylase enzyme is over-expressed and purified from bacteria. Next, labeled RNA substrate is prepared. Deadenylation reactions are performed, and reaction products are analyzed by denaturing gel electrophoresis. Reaction rates are then determined quantitatively. Crucial controls and experimental parameters are described along with practical tips that promote success.
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Affiliation(s)
- Joel Hrit
- Genetics Training Program, Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Dr., Room 5301 MSRB3, SPC 5606, Ann Arbor, MI, 48109, USA
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Lee MC, Jänicke A, Beilharz TH. Using Klenow-mediated extension to measure poly(A)-tail length and position in the transcriptome. Methods Mol Biol 2014; 1125:25-42. [PMID: 24590777 DOI: 10.1007/978-1-62703-971-0_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The poly(A)-tail that terminates most mRNA and many noncoding RNA is a convenient "hook" to isolate mRNA. However the length of this tail and its position within the primary RNA transcript can also hold diagnostic value for RNA metabolism. In general, mRNA with a long poly(A)-tail is well translated, whereas a short poly(A)-tail can indicate translational silencing. A short poly(A)-tail is also appended to RNA-decay intermediates via the TRAMP complex. A number of approaches have been developed to measure the length and position of the poly(A)-tail. Here, we describe a simple method to "tag" adenylated RNA using the native function of DNA polymerase I to extend an RNA primer on a DNA template in second-strand DNA synthesis. This function can be harnessed as a means to purify, visualize, and quantitate poly(A)-dynamics of individual RNA and the transcriptome en masse.
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Affiliation(s)
- Man Chun Lee
- Department of Biochemistry and Molecular Biology, Monash University Australia, Melbourne, VIC, Australia
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Abstract
Heritable differences in gene expression between individuals are an important source of phenotypic variation. The question of how closely the effects of genetic variation on protein levels mirror those on mRNA levels remains open. Here, we addressed this question by using ribosome profiling to examine how genetic differences between two strains of the yeast S. cerevisiae affect translation. Strain differences in translation were observed for hundreds of genes. Allele specific measurements in the diploid hybrid between the two strains revealed roughly half as many cis-acting effects on translation as were observed for mRNA levels. In both the parents and the hybrid, most effects on translation were of small magnitude, such that the direction of an mRNA difference was typically reflected in a concordant footprint difference. The relative importance of cis and trans acting variation on footprint levels was similar to that for mRNA levels. There was a tendency for translation to cause larger footprint differences than expected given the respective mRNA differences. This is in contrast to translational differences between yeast species that have been reported to more often oppose than reinforce mRNA differences. Finally, we catalogued instances of premature translation termination in the two yeast strains and also found several instances where erroneous reference gene annotations lead to apparent nonsense mutations that in fact reside outside of the translated gene body. Overall, genetic influences on translation subtly modulate gene expression differences, and translation does not create strong discrepancies between genetic influences on mRNA and protein levels. Individuals in a species differ from each other in many ways. For many traits, a fraction of this variation is genetic—it is caused by DNA sequence variants in the genome of each individual. Some of these variants influence traits by altering how much certain genes are expressed, i.e. how many mRNA and protein molecules are made in different individuals. Surprisingly, earlier work has found that the effects of genetic variants on mRNA and protein levels for the same genes appear to be very different. Many variants appeared to influence only mRNA (but not protein) levels, and vice versa. In this paper, we studied this question by using a technique called “ribosome profiling” to measure translation (the cellular process of reading mRNA molecules and synthesizing protein molecules) in two yeast strains. We found that the genetic differences between these two strains influence translation for hundreds of genes. Because most of these effects were small in magnitude, they explain at most a small fraction of the discrepancies between the effects of genetic variants on mRNA and protein levels.
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