1
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Lancaster CL, Yalamanchili PS, Goldy JN, Leung SW, Corbett AH, Moberg KH. The RNA-binding protein Nab2 regulates levels of the RhoGEF Trio to govern axon and dendrite morphology. Mol Biol Cell 2024; 35:ar109. [PMID: 38985523 PMCID: PMC11321036 DOI: 10.1091/mbc.e24-04-0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 06/17/2024] [Accepted: 07/02/2024] [Indexed: 07/12/2024] Open
Abstract
The Drosophila RNA-binding protein (RBP) Nab2 acts in neurons to regulate neurodevelopment and is orthologous to the human intellectual disability-linked RBP, ZC3H14. Nab2 governs axon projection in mushroom body neurons and limits dendritic arborization of class IV sensory neurons in part by regulating splicing events in ∼150 mRNAs. Analysis of the Sex-lethal (Sxl) mRNA revealed that Nab2 promotes an exon-skipping event and regulates m6A methylation on Sxl pre-mRNA by the Mettl3 methyltransferase. Mettl3 heterozygosity broadly rescues Nab2null phenotypes implying that Nab2 acts through similar mechanisms on other RNAs, including unidentified targets involved in neurodevelopment. Here, we show that Nab2 and Mettl3 regulate the removal of a 5'UTR (untranslated region) intron in the trio pre-mRNA. Trio utilizes two GEF domains to balance Rac and RhoGTPase activity. Intriguingly, an isoform of Trio containing only the RhoGEF domain, GEF2, is depleted in Nab2null nervous tissue. Expression of Trio-GEF2 rescues projection defects in Nab2null axons and dendrites, while the GEF1 Rac1-regulatory domain exacerbates these defects, suggesting Nab2-mediated regulation Trio-GEF activities. Collectively, these data indicate that Nab2-regulated processing of trio is critical for balancing Trio-GEF1 and -GEF2 activity and show that Nab2, Mettl3, and Trio function in a common pathway that shapes axon and dendrite morphology.
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Affiliation(s)
- Carly L. Lancaster
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Pranav S. Yalamanchili
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
| | - Jordan N. Goldy
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Sara W. Leung
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
| | - Anita H. Corbett
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
| | - Kenneth H. Moberg
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
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2
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Neumann H, Bartle L, Bonnell E, Wellinger RJ. Ratcheted transport and sequential assembly of the yeast telomerase RNP. Cell Rep 2023; 42:113565. [PMID: 38096049 DOI: 10.1016/j.celrep.2023.113565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/04/2023] [Accepted: 11/22/2023] [Indexed: 12/30/2023] Open
Abstract
The telomerase ribonucleoprotein particle (RNP) replenishes telomeric DNA and minimally requires an RNA component and a catalytic protein subunit. However, telomerase RNP maturation is an intricate process occurring in several subcellular compartments and is incompletely understood. Here, we report how the co-transcriptional association of key telomerase components and nuclear export factors leads to an export-competent, but inactive, RNP. Export is dependent on the 5' cap, the 3' extension of unprocessed telomerase RNA, and protein associations. When the RNP reaches the cytoplasm, an extensive protein swap occurs, the RNA is trimmed to its mature length, and the essential catalytic Est2 protein joins the RNP. This mature and active complex is then reimported into the nucleus as its final destination and last processing steps. The irreversible processing events on the RNA thus support a ratchet-type model of telomerase maturation, with only a single nucleo-cytoplasmic cycle that is essential for the assembly of mature telomerase.
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Affiliation(s)
- Hannah Neumann
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201 Rue Jean Mignault, Sherbrooke, QC J1E 4K8, Canada
| | - Louise Bartle
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201 Rue Jean Mignault, Sherbrooke, QC J1E 4K8, Canada; Research Center on Aging (CdRV), 1036 rue Belvedere Sud, Sherbrooke, QC J1H 4C4, Canada
| | - Erin Bonnell
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201 Rue Jean Mignault, Sherbrooke, QC J1E 4K8, Canada
| | - Raymund J Wellinger
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201 Rue Jean Mignault, Sherbrooke, QC J1E 4K8, Canada; Research Center on Aging (CdRV), 1036 rue Belvedere Sud, Sherbrooke, QC J1H 4C4, Canada.
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3
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Asada R, Dominguez A, Montpetit B. Single-molecule quantitation of RNA-binding protein occupancy and stoichiometry defines a role for Yra1 (Aly/REF) in nuclear mRNP organization. Cell Rep 2023; 42:113415. [PMID: 37963019 PMCID: PMC10841842 DOI: 10.1016/j.celrep.2023.113415] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 10/09/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023] Open
Abstract
RNA-binding proteins (RBPs) interact with mRNA to form supramolecular complexes called messenger ribonucleoprotein (mRNP) particles. These dynamic assemblies direct and regulate individual steps of gene expression; however, their composition and functional importance remain largely unknown. Here, we develop a total internal reflection fluorescence-based single-molecule imaging assay to investigate stoichiometry and co-occupancy of 15 RBPs within mRNPs from Saccharomyces cerevisiae. We show compositional heterogeneity of single mRNPs and plasticity across different growth conditions, with major co-occupants of mRNPs containing the nuclear cap-binding complex identified as Yra1 (1-10 copies), Nab2 (1-6 copies), and Npl3 (1-6 copies). Multicopy Yra1-bound mRNPs are specifically co-occupied by the THO complex and assembled on mRNAs biased by transcript length and RNA secondary structure. Yra1 depletion results in decreased compaction of nuclear mRNPs demonstrating a packaging function. Together, we provide a quantitative framework for gene- and condition-dependent RBP occupancy and stoichiometry in individual nuclear mRNPs.
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Affiliation(s)
- Ryuta Asada
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA
| | - Andrew Dominguez
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA; Biochemistry, Molecular, Cellular, and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA
| | - Ben Montpetit
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA; Biochemistry, Molecular, Cellular, and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA.
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4
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Joshua IM, Lin M, Mardjuki A, Mazzola A, Höfken T. A Protein-Protein Interaction Analysis Suggests a Wide Range of New Functions for the p21-Activated Kinase (PAK) Ste20. Int J Mol Sci 2023; 24:15916. [PMID: 37958899 PMCID: PMC10647699 DOI: 10.3390/ijms242115916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
The p21-activated kinases (PAKs) are important signaling proteins. They contribute to a surprisingly wide range of cellular processes and play critical roles in a number of human diseases including cancer, neurological disorders and cardiac diseases. To get a better understanding of PAK functions, mechanisms and integration of various cellular activities, we screened for proteins that bind to the budding yeast PAK Ste20 as an example, using the split-ubiquitin technique. We identified 56 proteins, most of them not described previously as Ste20 interactors. The proteins fall into a small number of functional categories such as vesicle transport and translation. We analyzed the roles of Ste20 in glucose metabolism and gene expression further. Ste20 has a well-established role in the adaptation to changing environmental conditions through the stimulation of mitogen-activated protein kinase (MAPK) pathways which eventually leads to transcription factor activation. This includes filamentous growth, an adaptation to nutrient depletion. Here we show that Ste20 also induces filamentous growth through interaction with nuclear proteins such as Sac3, Ctk1 and Hmt1, key regulators of gene expression. Combining our observations and the data published by others, we suggest that Ste20 has several new and unexpected functions.
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Affiliation(s)
| | - Meng Lin
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
| | - Ariestia Mardjuki
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
| | - Alessandra Mazzola
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Department of Biopathology and Medical and Forensic Biotechnologies, University of Palermo, 90133 Palermo, Italy
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
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5
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Xie Y, Gao S, Zhang K, Bhat P, Clarke BP, Batten K, Mei M, Gazzara M, Shay JW, Lynch KW, Angelos AE, Hill PS, Ivey AL, Fontoura BMA, Ren Y. Structural basis for high-order complex of SARNP and DDX39B to facilitate mRNP assembly. Cell Rep 2023; 42:112988. [PMID: 37578863 PMCID: PMC10508174 DOI: 10.1016/j.celrep.2023.112988] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/10/2023] [Accepted: 07/31/2023] [Indexed: 08/16/2023] Open
Abstract
mRNA in eukaryotic cells is packaged into highly compacted ribonucleoprotein particles (mRNPs) in the nucleus and exported to the cytoplasm for translation. mRNP packaging and export require the evolutionarily conserved transcription-export (TREX) complex. TREX facilitates loading of various RNA-binding proteins on mRNA through the action of its DDX39B subunit. SARNP (Tho1 [transcriptional defect of Hpr1 by overexpression 1] in yeast) is shown to interact with DDX39B and affect mRNA export. The molecular mechanism of how SARNP recognizes DDX39B and functions in mRNP assembly is unclear. Here, we determine the crystal structure of a Tho1/DDX39B/RNA complex, revealing a multivalent interaction mediated by tandem DDX39B interacting motifs in SARNP/Tho1. The high-order complex of SARNP and DDX39B is evolutionarily conserved, and human SARNP can engage with five DDX39B molecules. RNA sequencing (RNA-seq) from SARNP knockdown cells shows the most affected RNAs in export are GC rich. Our work suggests the role of the high-order SARNP/DDX39B/RNA complex in mRNP assembly and export.
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Affiliation(s)
- Yihu Xie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Shengyan Gao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Ke Zhang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Prasanna Bhat
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Bradley P Clarke
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Kimberly Batten
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Menghan Mei
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Matthew Gazzara
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Kristen W Lynch
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexia E Angelos
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Pate S Hill
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Austin L Ivey
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Beatriz M A Fontoura
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA.
| | - Yi Ren
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA.
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6
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Pacheco-Fiallos B, Vorländer MK, Riabov-Bassat D, Fin L, O'Reilly FJ, Ayala FI, Schellhaas U, Rappsilber J, Plaschka C. mRNA recognition and packaging by the human transcription-export complex. Nature 2023; 616:828-835. [PMID: 37020021 PMCID: PMC7614608 DOI: 10.1038/s41586-023-05904-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 03/01/2023] [Indexed: 04/07/2023]
Abstract
Newly made mRNAs are processed and packaged into mature ribonucleoprotein complexes (mRNPs) and are recognized by the essential transcription-export complex (TREX) for nuclear export1,2. However, the mechanisms of mRNP recognition and three-dimensional mRNP organization are poorly understood3. Here we report cryo-electron microscopy and tomography structures of reconstituted and endogenous human mRNPs bound to the 2-MDa TREX complex. We show that mRNPs are recognized through multivalent interactions between the TREX subunit ALYREF and mRNP-bound exon junction complexes. Exon junction complexes can multimerize through ALYREF, which suggests a mechanism for mRNP organization. Endogenous mRNPs form compact globules that are coated by multiple TREX complexes. These results reveal how TREX may simultaneously recognize, compact and protect mRNAs to promote their packaging for nuclear export. The organization of mRNP globules provides a framework to understand how mRNP architecture facilitates mRNA biogenesis and export.
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Affiliation(s)
- Belén Pacheco-Fiallos
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Matthias K Vorländer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Daria Riabov-Bassat
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Laura Fin
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Francis J O'Reilly
- Bioanalytics Unit, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Farja I Ayala
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Ulla Schellhaas
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Juri Rappsilber
- Bioanalytics Unit, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria.
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7
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Kim B, Seol J, Kim YK, Lee JB. Single-molecule visualization of mRNA circularization during translation. Exp Mol Med 2023; 55:283-289. [PMID: 36720916 PMCID: PMC9981743 DOI: 10.1038/s12276-023-00933-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/04/2022] [Accepted: 12/04/2022] [Indexed: 02/02/2023] Open
Abstract
Translation is mediated by precisely orchestrated sequential interactions among translation initiation components, mRNA, and ribosomes. Biochemical, structural, and genetic techniques have revealed the fundamental mechanism that determines what occurs and when, where and in what order. Most mRNAs are circularized via the eIF4E-eIF4G-PABP interaction, which stabilizes mRNAs and enhances translation by recycling ribosomes. However, studies using single-molecule fluorescence imaging have allowed for the visualization of complex data that opposes the traditional "functional circularization" theory. Here, we briefly introduce single-molecule techniques applied to studies on mRNA circularization and describe the results of in vitro and live-cell imaging. Finally, we discuss relevant insights and questions gained from single-molecule research related to translation.
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Affiliation(s)
- Byungju Kim
- Department of Physics, Pohang University of Science & Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jincheol Seol
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, 37673, Republic of Korea
| | - Yoon Ki Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Jong-Bong Lee
- Department of Physics, Pohang University of Science & Technology (POSTECH), Pohang, 37673, Republic of Korea.
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, 37673, Republic of Korea.
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8
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Ashkenazy-Titelman A, Atrash MK, Boocholez A, Kinor N, Shav-Tal Y. RNA export through the nuclear pore complex is directional. Nat Commun 2022; 13:5881. [PMID: 36202822 PMCID: PMC9537521 DOI: 10.1038/s41467-022-33572-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 09/22/2022] [Indexed: 11/10/2022] Open
Abstract
The changes occurring in mRNA organization during nucleo-cytoplasmic transport and export, are not well understood. Moreover, directionality of mRNA passage through the nuclear pore complex (NPC) has not been examined within individual NPCs. Here we find that an mRNP is compact during nucleoplasmic travels compared to a more open structure after transcription and at the nuclear periphery. Compaction levels of nuclear transcripts can be modulated by varying levels of SR proteins and by changing genome organization. Nuclear mRNPs are mostly rod-shaped with distant 5'/3'-ends, although for some, the ends are in proximity. The latter is more abundant in the cytoplasm and can be modified by translation inhibition. mRNAs and lncRNAs exiting the NPC exhibit predominant 5'-first export. In some cases, several adjacent NPCs are engaged in export of the same mRNA suggesting 'gene gating'. Altogether, we show that the mRNP is a flexible structure during travels, with 5'-directionality during export.
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Affiliation(s)
- Asaf Ashkenazy-Titelman
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Mohammad Khaled Atrash
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Alon Boocholez
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Noa Kinor
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Yaron Shav-Tal
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, 5290002, Israel.
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9
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Vorländer MK, Pacheco-Fiallos B, Plaschka C. Structural basis of mRNA maturation: Time to put it together. Curr Opin Struct Biol 2022; 75:102431. [PMID: 35930970 DOI: 10.1016/j.sbi.2022.102431] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/02/2022] [Accepted: 06/14/2022] [Indexed: 11/27/2022]
Abstract
In eukaryotes, the expression of genetic information begins in the cell nucleus with precursor messenger RNA (pre-mRNA) transcription and processing into mature mRNA. The mRNA is subsequently recognized and packaged by proteins into an mRNA ribonucleoprotein complex (mRNP) and exported to the cytoplasm for translation. Each of the nuclear mRNA maturation steps is carried out by a dedicated molecular machine. Here, we highlight recent structural and mechanistic insights into how these machines function, including the capping enzyme, the spliceosome, the 3'-end processing machinery, and the transcription-export complex. While we increasingly understand individual steps of nuclear gene expression, many questions remain. For example, we are only beginning to reveal how mature mRNAs are recognized and packaged for nuclear export and how mRNA maturation events are coupled to transcription and to each other. Advances in the preparation of recombinant and endogenous protein-nucleic acid complexes, cryo-electron microscopy, and machine learning promise exciting insights into the mechanisms of nuclear gene expression and its spatial organization.
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Affiliation(s)
- Matthias K Vorländer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria. https://twitter.com/@MVorlandr
| | - Belén Pacheco-Fiallos
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria. https://twitter.com/@bpachecofiallos
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
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10
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James K, Alsobhe A, Cockell SJ, Wipat A, Pocock M. Integration of probabilistic functional networks without an external Gold Standard. BMC Bioinformatics 2022; 23:302. [PMID: 35879662 PMCID: PMC9316706 DOI: 10.1186/s12859-022-04834-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 07/11/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Probabilistic functional integrated networks (PFINs) are designed to aid our understanding of cellular biology and can be used to generate testable hypotheses about protein function. PFINs are generally created by scoring the quality of interaction datasets against a Gold Standard dataset, usually chosen from a separate high-quality data source, prior to their integration. Use of an external Gold Standard has several drawbacks, including data redundancy, data loss and the need for identifier mapping, which can complicate the network build and impact on PFIN performance. Additionally, there typically are no Gold Standard data for non-model organisms. RESULTS We describe the development of an integration technique, ssNet, that scores and integrates both high-throughput and low-throughout data from a single source database in a consistent manner without the need for an external Gold Standard dataset. Using data from Saccharomyces cerevisiae we show that ssNet is easier and faster, overcoming the challenges of data redundancy, Gold Standard bias and ID mapping. In addition ssNet results in less loss of data and produces a more complete network. CONCLUSIONS The ssNet method allows PFINs to be built successfully from a single database, while producing comparable network performance to networks scored using an external Gold Standard source and with reduced data loss.
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Affiliation(s)
- Katherine James
- Department of Applied Sciences, Northumbria University, Sandyford Rd, Newcastle upon Tyne, NE1 8ST, UK. .,Interdisciplinary Computing and Complex BioSystems Group, Newcastle University, Science Square, Newcastle upon Tyne, NE4 5TG, UK.
| | - Aoesha Alsobhe
- Interdisciplinary Computing and Complex BioSystems Group, Newcastle University, Science Square, Newcastle upon Tyne, NE4 5TG, UK.,Saudi Electronic University, Abi Bakr As Siddiq Branch Rd, Riyadh, 1332, Saudi Arabia
| | - Simon J Cockell
- School of Biomedical, Nutritional and Sports Science, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Anil Wipat
- Interdisciplinary Computing and Complex BioSystems Group, Newcastle University, Science Square, Newcastle upon Tyne, NE4 5TG, UK
| | - Matthew Pocock
- Interdisciplinary Computing and Complex BioSystems Group, Newcastle University, Science Square, Newcastle upon Tyne, NE4 5TG, UK
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11
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Park HS, Lee J, Lee HS, Ahn SH, Ryu HY. Nuclear mRNA Export and Aging. Int J Mol Sci 2022; 23:5451. [PMID: 35628261 PMCID: PMC9142925 DOI: 10.3390/ijms23105451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/10/2022] [Accepted: 05/12/2022] [Indexed: 02/04/2023] Open
Abstract
The relationship between transcription and aging is one that has been studied intensively and experimentally with diverse attempts. However, the impact of the nuclear mRNA export on the aging process following its transcription is still poorly understood, although the nuclear events after transcription are coupled closely with the transcription pathway because the essential factors required for mRNA transport, namely TREX, TREX-2, and nuclear pore complex (NPC), physically and functionally interact with various transcription factors, including the activator/repressor and pre-mRNA processing factors. Dysregulation of the mediating factors for mRNA export from the nucleus generally leads to the aberrant accumulation of nuclear mRNA and further impairment in the vegetative growth and normal lifespan and the pathogenesis of neurodegenerative diseases. The optimal stoichiometry and density of NPC are destroyed during the process of cellular aging, and their damage triggers a defect of function in the nuclear permeability barrier. This review describes recent findings regarding the role of the nuclear mRNA export in cellular aging and age-related neurodegenerative disorders.
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Affiliation(s)
- Hyun-Sun Park
- Department of Biochemistry, Inje University College of Medicine, Busan 50834, Korea;
| | - Jongbok Lee
- Department of Biological and Chemical Engineering, Hongik University, 2639, Sejong-ro, Jochiwon-eup, Sejong-si 30016, Korea;
| | - Hyun-Shik Lee
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of National Sciences, Kyungpook National University, Daegu 41566, Korea;
| | - Seong Hoon Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, ERICA Campus, Hanyang University, Ansan 15588, Korea
| | - Hong-Yeoul Ryu
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of National Sciences, Kyungpook National University, Daegu 41566, Korea;
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12
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Rounds JC, Corgiat EB, Ye C, Behnke JA, Kelly SM, Corbett AH, Moberg KH. The disease-associated proteins Drosophila Nab2 and Ataxin-2 interact with shared RNAs and coregulate neuronal morphology. Genetics 2022; 220:iyab175. [PMID: 34791182 PMCID: PMC8733473 DOI: 10.1093/genetics/iyab175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 09/27/2021] [Indexed: 01/05/2023] Open
Abstract
Nab2 encodes the Drosophila melanogaster member of a conserved family of zinc finger polyadenosine RNA-binding proteins (RBPs) linked to multiple steps in post-transcriptional regulation. Mutation of the Nab2 human ortholog ZC3H14 gives rise to an autosomal recessive intellectual disability but understanding of Nab2/ZC3H14 function in metazoan nervous systems is limited, in part because no comprehensive identification of metazoan Nab2/ZC3H14-associated RNA transcripts has yet been conducted. Moreover, many Nab2/ZC3H14 functional protein partnerships remain unidentified. Here, we present evidence that Nab2 genetically interacts with Ataxin-2 (Atx2), which encodes a neuronal translational regulator, and that these factors coordinately regulate neuronal morphology, circadian behavior, and adult viability. We then present the first high-throughput identifications of Nab2- and Atx2-associated RNAs in Drosophila brain neurons using RNA immunoprecipitation-sequencing (RIP-Seq). Critically, the RNA interactomes of each RBP overlap, and Nab2 exhibits high specificity in its RNA associations in neurons in vivo, associating with a small fraction of all polyadenylated RNAs. The identities of shared associated transcripts (e.g., drk, me31B, stai) and of transcripts specific to Nab2 or Atx2 (e.g., Arpc2 and tea) promise insight into neuronal functions of, and genetic interactions between, each RBP. Consistent with prior biochemical studies, Nab2-associated neuronal RNAs are overrepresented for internal A-rich motifs, suggesting these sequences may partially mediate Nab2 target selection. These data support a model where Nab2 functionally opposes Atx2 in neurons, demonstrate Nab2 shares associated neuronal RNAs with Atx2, and reveal Drosophila Nab2 associates with a more specific subset of polyadenylated mRNAs than its polyadenosine affinity alone may suggest.
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Affiliation(s)
- J Christopher Rounds
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Edwin B Corgiat
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Changtian Ye
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Joseph A Behnke
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Seth M Kelly
- Department of Biology, The College of Wooster, Wooster, OH 44691, USA
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Kenneth H Moberg
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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13
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De Magistris P. The Great Escape: mRNA Export through the Nuclear Pore Complex. Int J Mol Sci 2021; 22:ijms222111767. [PMID: 34769195 PMCID: PMC8583845 DOI: 10.3390/ijms222111767] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 12/30/2022] Open
Abstract
Nuclear export of messenger RNA (mRNA) through the nuclear pore complex (NPC) is an indispensable step to ensure protein translation in the cytoplasm of eukaryotic cells. mRNA is not translocated on its own, but it forms ribonuclear particles (mRNPs) in association with proteins that are crucial for its metabolism, some of which; like Mex67/MTR2-NXF1/NXT1; are key players for its translocation to the cytoplasm. In this review, I will summarize our current body of knowledge on the basic characteristics of mRNA export through the NPC. To be granted passage, the mRNP cargo needs to bind transport receptors, which facilitate the nuclear export. During NPC transport, mRNPs undergo compositional and conformational changes. The interactions between mRNP and the central channel of NPC are described; together with the multiple quality control steps that mRNPs undergo at the different rings of the NPC to ensure only proper export of mature transcripts to the cytoplasm. I conclude by mentioning new opportunities that arise from bottom up approaches for a mechanistic understanding of nuclear export.
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14
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Eyboulet F, Jeronimo C, Côté J, Robert F. The deubiquitylase Ubp15 couples transcription to mRNA export. eLife 2020; 9:e61264. [PMID: 33226341 PMCID: PMC7682988 DOI: 10.7554/elife.61264] [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: 07/20/2020] [Accepted: 11/04/2020] [Indexed: 12/16/2022] Open
Abstract
Nuclear export of messenger RNAs (mRNAs) is intimately coupled to their synthesis. pre-mRNAs assemble into dynamic ribonucleoparticles as they are being transcribed, processed, and exported. The role of ubiquitylation in this process is increasingly recognized but, while a few E3 ligases have been shown to regulate nuclear export, evidence for deubiquitylases is currently lacking. Here we identified deubiquitylase Ubp15 as a regulator of nuclear export in Saccharomyces cerevisiae. Ubp15 interacts with both RNA polymerase II and the nuclear pore complex, and its deletion reverts the nuclear export defect of E3 ligase Rsp5 mutants. The deletion of UBP15 leads to hyper-ubiquitylation of the main nuclear export receptor Mex67 and affects its association with THO, a complex coupling transcription to mRNA processing and involved in the recruitment of mRNA export factors to nascent transcripts. Collectively, our data support a role for Ubp15 in coupling transcription to mRNA export.
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Affiliation(s)
- Fanny Eyboulet
- Institut de recherches cliniques de MontréalMontréalCanada
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Axe Oncologie du Centre de Recherche du CHU de Québec-Université LavalQuébec CityCanada
| | - Célia Jeronimo
- Institut de recherches cliniques de MontréalMontréalCanada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Axe Oncologie du Centre de Recherche du CHU de Québec-Université LavalQuébec CityCanada
| | - François Robert
- Institut de recherches cliniques de MontréalMontréalCanada
- Département de Médecine, Faculté de Médecine, Université de MontréalMontréalCanada
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15
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Alpert T, Straube K, Carrillo Oesterreich F, Herzel L, Neugebauer KM. Widespread Transcriptional Readthrough Caused by Nab2 Depletion Leads to Chimeric Transcripts with Retained Introns. Cell Rep 2020; 33:108324. [PMID: 33113357 DOI: 10.1016/j.celrep.2020.108324] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/15/2020] [Accepted: 10/07/2020] [Indexed: 01/26/2023] Open
Abstract
Nascent RNA sequencing has revealed that pre-mRNA splicing can occur shortly after introns emerge from RNA polymerase II (RNA Pol II). Differences in co-transcriptional splicing profiles suggest regulation by cis- and/or trans-acting factors. Here, we use single-molecule intron tracking (SMIT) to identify a cohort of regulators by machine learning in budding yeast. Of these, Nab2 displays reduced co-transcriptional splicing when depleted. Unexpectedly, these splicing defects are attributable to aberrant "intrusive" transcriptional readthrough from upstream genes, as revealed by long-read sequencing. Transcripts that originate from the intron-containing gene's own transcription start site (TSS) are efficiently spliced, indicating no direct role of Nab2 in splicing per se. This work highlights the coupling between transcription, splicing, and 3' end formation in the context of gene organization along chromosomes. We conclude that Nab2 is required for proper 3' end processing, which ensures gene-specific control of co-transcriptional RNA processing.
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Affiliation(s)
- Tara Alpert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | | | - Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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16
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Zarnack K, Balasubramanian S, Gantier MP, Kunetsky V, Kracht M, Schmitz ML, Sträßer K. Dynamic mRNP Remodeling in Response to Internal and External Stimuli. Biomolecules 2020; 10:biom10091310. [PMID: 32932892 PMCID: PMC7565591 DOI: 10.3390/biom10091310] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023] Open
Abstract
Signal transduction and the regulation of gene expression are fundamental processes in every cell. RNA-binding proteins (RBPs) play a key role in the post-transcriptional modulation of gene expression in response to both internal and external stimuli. However, how signaling pathways regulate the assembly of RBPs with mRNAs remains largely unknown. Here, we summarize observations showing that the formation and composition of messenger ribonucleoprotein particles (mRNPs) is dynamically remodeled in space and time by specific signaling cascades and the resulting post-translational modifications. The integration of signaling events with gene expression is key to the rapid adaptation of cells to environmental changes and stress. Only a combined approach analyzing the signal transduction pathways and the changes in post-transcriptional gene expression they cause will unravel the mechanisms coordinating these important cellular processes.
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Affiliation(s)
- Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany;
| | | | - Michael P. Gantier
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia;
- Department of Molecular and Translational Science, Monash University, Clayton, VIC 3800, Australia
| | - Vladislav Kunetsky
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany;
| | - Michael Kracht
- Rudolf Buchheim Institute of Pharmacology, FB11, Justus Liebig University, 35392 Giessen, Germany;
| | - M. Lienhard Schmitz
- Institute of Biochemistry, FB11, Justus Liebig University, 35392 Giessen, Germany;
| | - Katja Sträßer
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany;
- Correspondence:
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17
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Abstract
The proper regulation of mRNA processing, localization, translation, and degradation occurs on mRNPs. However, the global principles of mRNP organization are poorly understood. We utilize the limited, but existing, information available to present a speculative synthesis of mRNP organization with the following key points. First, mRNPs form a compacted structure due to the inherent folding of RNA. Second, the ribosome is the principal mechanism by which mRNA regions are partially decompacted. Third, mRNPs are 50%-80% protein by weight, consistent with proteins modulating mRNP organization, but also suggesting the majority of mRNA sequences are not directly interacting with RNA-binding proteins. Finally, the ratio of mRNA-binding proteins to mRNAs is higher in the nucleus to allow effective RNA processing and limit the potential for nuclear RNA based aggregation. This synthesis of mRNP understanding provides a model for mRNP biogenesis, structure, and regulation with multiple implications.
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Affiliation(s)
- Anthony Khong
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Roy Parker
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
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18
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Muellner J, Schmidt KH. Yeast Genome Maintenance by the Multifunctional PIF1 DNA Helicase Family. Genes (Basel) 2020; 11:genes11020224. [PMID: 32093266 PMCID: PMC7073672 DOI: 10.3390/genes11020224] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 12/04/2022] Open
Abstract
The two PIF1 family helicases in Saccharomyces cerevisiae, Rrm3, and ScPif1, associate with thousands of sites throughout the genome where they perform overlapping and distinct roles in telomere length maintenance, replication through non-histone proteins and G4 structures, lagging strand replication, replication fork convergence, the repair of DNA double-strand break ends, and transposable element mobility. ScPif1 and its fission yeast homolog Pfh1 also localize to mitochondria where they protect mitochondrial genome integrity. In addition to yeast serving as a model system for the rapid functional evaluation of human Pif1 variants, yeast cells lacking Rrm3 have proven useful for elucidating the cellular response to replication fork pausing at endogenous sites. Here, we review the increasingly important cellular functions of the yeast PIF1 helicases in maintaining genome integrity, and highlight recent advances in our understanding of their roles in facilitating fork progression through replisome barriers, their functional interactions with DNA repair, and replication stress response pathways.
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Affiliation(s)
- Julius Muellner
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620, USA;
- Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Kristina H. Schmidt
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620, USA;
- Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
- Correspondence:
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19
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Abstract
In eukaryotes, the separation of translation from transcription by the nuclear envelope enables mRNA modifications such as capping, splicing, and polyadenylation. These modifications are mediated by a spectrum of ribonuclear proteins that associate with preRNA transcripts, coordinating the different steps and coupling them to nuclear export, ensuring that only mature transcripts reach the cytoplasmic translation machinery. Although the components of this machinery have been identified and considerable functional insight has been achieved, a number of questions remain outstanding about mRNA nuclear export and how it is integrated into the nuclear phase of the gene expression pathway. Nuclear export factors mediate mRNA transit through nuclear pores to the cytoplasm, after which these factors are removed from the mRNA, preventing transcripts from returning to the nucleus. However, as outlined in this review, several aspects of the mechanism by which transport factor binding and release are mediated remain unclear, as are the roles of accessory nuclear components in these processes. Moreover, the mechanisms by which completion of mRNA splicing and polyadenylation are recognized, together with how they are coordinated with nuclear export, also remain only partially characterized. One attractive hypothesis is that dissociating poly(A) polymerase from the cleavage and polyadenylation machinery could signal completion of mRNA maturation and thereby provide a mechanism for initiating nuclear export. The impressive array of genetic, molecular, cellular, and structural data that has been generated about these systems now provides many of the tools needed to define the precise mechanisms involved in these processes and how they are integrated.
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Affiliation(s)
- Murray Stewart
- From the MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
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20
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Gay S, Piccini D, Bruhn C, Ricciardi S, Soffientini P, Carotenuto W, Biffo S, Foiani M. A Mad2-Mediated Translational Regulatory Mechanism Promoting S-Phase Cyclin Synthesis Controls Origin Firing and Survival to Replication Stress. Mol Cell 2019; 70:628-638.e5. [PMID: 29775579 PMCID: PMC5972228 DOI: 10.1016/j.molcel.2018.04.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/26/2018] [Accepted: 04/23/2018] [Indexed: 11/03/2022]
Abstract
Cell survival to replication stress depends on the activation of the Mec1ATR-Rad53 checkpoint response that protects the integrity of stalled forks and controls the origin firing program. Here we found that Mad2, a member of the spindle assembly checkpoint (SAC), contributes to efficient origin firing and to cell survival in response to replication stress. We show that Rad53 and Mad2 promote S-phase cyclin expression through different mechanisms: while Rad53 influences Clb5,6 degradation, Mad2 promotes their protein synthesis. We found that Mad2 co-sediments with polysomes and modulates the association of the translation inhibitor Caf204E-BP with the translation machinery and the initiation factor eIF4E. This Mad2-dependent translational regulatory process does not depend on other SAC proteins. Altogether our observations indicate that Mad2 has an additional function outside of mitosis to control DNA synthesis and collaborates with the Mec1-Rad53 regulatory axis to allow cell survival in response to replication stress.
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Affiliation(s)
- Sophie Gay
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
| | - Daniele Piccini
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Christopher Bruhn
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Sara Ricciardi
- Fondazione Istituto Nazionale Genetica Molecolare, Via Francesco Sforza, 32, 20122 Milan, Italy; Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Paolo Soffientini
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Walter Carotenuto
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Stefano Biffo
- Fondazione Istituto Nazionale Genetica Molecolare, Via Francesco Sforza, 32, 20122 Milan, Italy; Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Marco Foiani
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
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21
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The path of pre-ribosomes through the nuclear pore complex revealed by electron tomography. Nat Commun 2019; 10:497. [PMID: 30700705 PMCID: PMC6353910 DOI: 10.1038/s41467-019-08342-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 12/17/2018] [Indexed: 01/24/2023] Open
Abstract
Determining the path of single ribonucleoprotein (RNP) particles through the 100 nm-wide nuclear pore complex (NPC) by fluorescence microscopy remains challenging due to resolution limitation and RNP labeling constraints. By using high-pressure freezing and electron tomography, here we captured snapshots of the translocation of native RNP particles through NPCs in yeast and analyzed their trajectory at nanometer-scale resolution. Morphological and functional analyses indicate that these particles mostly correspond to pre-ribosomes. They are detected in 5–6% of the NPCs, with no apparent bias for NPCs adjacent to the nucleolus. Their path closely follows the central axis of the NPC through the nuclear and inner rings, but diverges at the cytoplasmic ring, suggesting interactions with the cytoplasmic nucleoporins. By applying a probabilistic queueing model to our data, we estimated that the dwell time of pre-ribosomes in the yeast NPC is ~90 ms. These data reveal distinct steps of pre-ribosome translocation through the NPC. Large protein complexes and ribonucleoprotein particles (RNPs) such as pre-ribosomes are transported from the nucleus to the cytoplasm through the nuclear pore complex (NPC). Here the authors use ultrafast freezing and electron tomography to catch snapshots of native RNPs crossing the NPC and estimate their transit time using a probabilistic model.
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22
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Fasken MB, Corbett AH, Stewart M. Structure-function relationships in the Nab2 polyadenosine-RNA binding Zn finger protein family. Protein Sci 2019; 28:513-523. [PMID: 30578643 PMCID: PMC6371209 DOI: 10.1002/pro.3565] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/15/2018] [Accepted: 12/17/2018] [Indexed: 12/12/2022]
Abstract
The poly(A) RNA binding Zn finger ribonucleoprotein Nab2 functions to control the length of 3' poly(A) tails in Saccharomyces cerevisiae as well as contributing to the integration of the nuclear export of mature mRNA with preceding steps in the nuclear phase of the gene expression pathway. Nab2 is constructed from an N-terminal PWI-fold domain, followed by QQQP and RGG motifs and then seven CCCH Zn fingers. The nuclear pore-associated proteins Gfd1 and Mlp1 bind to opposite sides of the Nab2 N-terminal domain and function in the nuclear export of mRNA, whereas the Zn fingers, especially fingers 5-7, bind to A-rich regions of mature transcripts and function to regulate poly(A) tail length as well as mRNA compaction prior to nuclear export. Nab2 Zn fingers 5-7 have a defined spatial arrangement, with fingers 5 and 7 arranged on one side of the cluster and finger 6 on the other side. This spatial arrangement facilitates the dimerization of Nab2 when bound to adenine-rich RNAs and regulates both the termination of 3' polyadenylation and transcript compaction. Nab2 also functions to coordinate steps in the nuclear phase of the gene expression pathway, such as splicing and polyadenylation, with the generation of mature mRNA and its nuclear export. Nab2 orthologues in higher Eukaryotes have similar domain structures and play roles associated with the regulation of splicing and polyadenylation. Importantly, mutations in the gene encoding the human Nab2 orthologue ZC3H14 and cause intellectual disability.
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Affiliation(s)
- Milo B Fasken
- Department of Biology, Emory University, Atlanta, Georgia 30322
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, Georgia 30322
| | - Murray Stewart
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
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23
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Mechanism and Regulation of Co-transcriptional mRNP Assembly and Nuclear mRNA Export. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:1-31. [DOI: 10.1007/978-3-030-31434-7_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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24
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Adivarahan S, Zenklusen D. Lessons from (pre-)mRNA Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:247-284. [DOI: 10.1007/978-3-030-31434-7_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Escaping nuclear decay: the significance of mRNA export for gene expression. Curr Genet 2018; 65:473-476. [DOI: 10.1007/s00294-018-0913-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 11/24/2018] [Accepted: 11/28/2018] [Indexed: 12/12/2022]
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26
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Chia SZ, Lai YW, Yagoub D, Lev S, Hamey JJ, Pang CNI, Desmarini D, Chen Z, Djordjevic JT, Erce MA, Hart-Smith G, Wilkins MR. Knockout of the Hmt1p Arginine Methyltransferase in Saccharomyces cerevisiae Leads to the Dysregulation of Phosphate-associated Genes and Processes. Mol Cell Proteomics 2018; 17:2462-2479. [PMID: 30206180 PMCID: PMC6283299 DOI: 10.1074/mcp.ra117.000214] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/14/2018] [Indexed: 11/06/2022] Open
Abstract
Hmt1p is the predominant arginine methyltransferase in Saccharomyces cerevisiae Its substrate proteins are involved in transcription, transcriptional regulation, nucleocytoplasmic transport and RNA splicing. Hmt1p-catalyzed methylation can also modulate protein-protein interactions. Hmt1p is conserved from unicellular eukaryotes through to mammals where its ortholog, PRMT1, is lethal upon knockout. In yeast, however, the effect of knockout on the transcriptome and proteome has not been described. Transcriptome analysis revealed downregulation of phosphate-responsive genes in hmt1Δ, including acid phosphatases PHO5, PHO11, and PHO12, phosphate transporters PHO84 and PHO89 and the vacuolar transporter chaperone VTC3 Analysis of the hmt1Δ proteome revealed decreased abundance of phosphate-associated proteins including phosphate transporter Pho84p, vacuolar alkaline phosphatase Pho8p, acid phosphatase Pho3p and subunits of the vacuolar transporter chaperone complex Vtc1p, Vtc3p and Vtc4p. Consistent with this, phosphate homeostasis was dysregulated in hmt1Δ cells, showing decreased extracellular phosphatase levels and decreased total Pi in phosphate-depleted medium. In vitro, we showed that transcription factor Pho4p can be methylated at Arg-241, which could explain phosphate dysregulation in hmt1Δ if interplay exists with phosphorylation at Ser-242 or Ser-243, or if Arg-241 methylation affects the capacity of Pho4p to homodimerize or interact with Pho2p. However, the Arg-241 methylation site was not validated in vivo and the localization of a Pho4p-GFP fusion in hmt1Δ was not different from wild type. To our knowledge, this is the first study to reveal an association between Hmt1p and phosphate homeostasis and one which suggests a regulatory link between S-adenosyl methionine and intracellular phosphate.
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Affiliation(s)
- Samantha Z Chia
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Yu-Wen Lai
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Daniel Yagoub
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Joshua J Hamey
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Chi Nam Ignatius Pang
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Zhiliang Chen
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Melissa A Erce
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Gene Hart-Smith
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Marc R Wilkins
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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27
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Adivarahan S, Livingston N, Nicholson B, Rahman S, Wu B, Rissland OS, Zenklusen D. Spatial Organization of Single mRNPs at Different Stages of the Gene Expression Pathway. Mol Cell 2018; 72:727-738.e5. [PMID: 30415950 PMCID: PMC6592633 DOI: 10.1016/j.molcel.2018.10.010] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/24/2018] [Accepted: 10/04/2018] [Indexed: 12/21/2022]
Abstract
mRNAs form ribonucleoprotein complexes (mRNPs) by association with proteins that are crucial for mRNA metabolism. While the mRNP proteome has been well characterized, little is known about mRNP organization. Using a single-molecule approach, we show that mRNA conformation changes depending on its cellular localization and translational state. Compared to nuclear mRNPs and lncRNPs, association with ribosomes decompacts individual mRNAs, while pharmacologically dissociating ribosomes or sequestering them into stress granules leads to increased compaction. Moreover, translating mRNAs rarely show co-localized 5' and 3' ends, indicating either that mRNAs are not translated in a closed-loop configuration, or that mRNA circularization is transient, suggesting that a stable closed-loop conformation is not a universal state for all translating mRNAs.
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Affiliation(s)
- Srivathsan Adivarahan
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Nathan Livingston
- The Department of Biophysics and Biophysical Chemistry, the Solomon Snyder Department of Neuroscience, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA
| | - Beth Nicholson
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Samir Rahman
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Bin Wu
- The Department of Biophysics and Biophysical Chemistry, the Solomon Snyder Department of Neuroscience, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA
| | - Olivia S Rissland
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Daniel Zenklusen
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada.
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28
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Higher-Order Organization Principles of Pre-translational mRNPs. Mol Cell 2018; 72:715-726.e3. [PMID: 30415953 DOI: 10.1016/j.molcel.2018.09.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/20/2018] [Accepted: 09/12/2018] [Indexed: 11/21/2022]
Abstract
Compared to noncoding RNAs (ncRNAs), such as rRNAs and ribozymes, for which high-resolution structures abound, little is known about the tertiary structures of mRNAs. In eukaryotic cells, newly made mRNAs are packaged with proteins in highly compacted mRNA particles (mRNPs), but the manner of this mRNA compaction is unknown. Here, we developed and implemented RIPPLiT (RNA immunoprecipitation and proximity ligation in tandem), a transcriptome-wide method for probing the 3D conformations of RNAs stably associated with defined proteins, in this case, exon junction complex (EJC) core factors. EJCs multimerize with other mRNP components to form megadalton-sized complexes that protect large swaths of newly synthesized mRNAs from endonuclease digestion. Unlike ncRNPs, wherein strong locus-specific structures predominate, mRNPs behave more like flexible polymers. Polymer analysis of proximity ligation data for hundreds of mRNA species demonstrates that nascent and pre-translational mammalian mRNAs are compacted by their associated proteins into linear rod-like structures.
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29
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Tudek A, Schmid M, Makaras M, Barrass JD, Beggs JD, Jensen TH. A Nuclear Export Block Triggers the Decay of Newly Synthesized Polyadenylated RNA. Cell Rep 2018; 24:2457-2467.e7. [PMID: 30157437 PMCID: PMC6130047 DOI: 10.1016/j.celrep.2018.07.103] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 05/31/2018] [Accepted: 07/30/2018] [Indexed: 12/11/2022] Open
Abstract
Genomes are promiscuously transcribed, necessitating mechanisms that facilitate the sorting of RNA for function or destruction. The polyA (pA) tail is one such distinguishing feature, which in the Saccharomyces cerevisiae nucleus is bound by the Nab2p protein, yielding transcript protection. As Nab2p also contacts the main nuclear export factor Mex67p, we asked whether transport kinetics contributes to RNA sorting. Indeed, 3' end sequencing of newly transcribed pA+ RNAs demonstrates that nuclear depletion of Mex67p elicits their instant and global decay. A similar phenotype is evident upon inactivation of other export factors and proportional to the amount of nuclear pA+ RNA. As RNA expression is partially rescued by Nab2p overexpression, we propose that an export block out-titrates Nab2p onto nuclear-retained pA+ RNA, reducing the pool of Nab2p available to protect new transcripts. More generally, we suggest that nuclear RNA decay, negotiated by Nab2p availability, aids in balancing cellular transcript supply with demand.
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Affiliation(s)
- Agnieszka Tudek
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Marius Makaras
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - J David Barrass
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Jean D Beggs
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark.
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30
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Diminished Ost3-dependent N-glycosylation of the BiP nucleotide exchange factor Sil1 is an adaptive response to reductive ER stress. Proc Natl Acad Sci U S A 2017; 114:12489-12494. [PMID: 29109265 DOI: 10.1073/pnas.1705641114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BiP (Kar2 in yeast) is an essential Hsp70 chaperone and master regulator of endoplasmic reticulum (ER) function. BiP's activity is regulated by its intrinsic ATPase activity that can be stimulated by two different nucleotide exchange factors, Sil1 and Lhs1. Both Sil1 and Lhs1 are glycoproteins, but how N-glycosylation regulates their function is not known. Here, we show that N-glycosylation of Sil1, but not of Lhs1, is diminished upon reductive stress. N-glycosylation of Sil1 is predominantly Ost3-dependent and requires a functional Ost3 CxxC thioredoxin motif. N-glycosylation of Lhs1 is largely Ost3-independent and independent of the CxxC motif. Unglycosylated Sil1 is not only functional but is more effective at rescuing loss of Lhs1 activity than N-glycosylated Sil1. Furthermore, substitution of the redox active cysteine pair C52 and C57 in the N terminus of Sil1 results in the Doa10-dependent ERAD of this mutant protein. We propose that reductive stress in the ER inhibits the Ost3-dependent N-glycosylation of Sil1, which regulates specific BiP functions appropriate to the needs of the ER under reductive stress.
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31
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Aibara S, Gordon JMB, Riesterer AS, McLaughlin SH, Stewart M. Structural basis for the dimerization of Nab2 generated by RNA binding provides insight into its contribution to both poly(A) tail length determination and transcript compaction in Saccharomyces cerevisiae. Nucleic Acids Res 2017; 45:1529-1538. [PMID: 28180315 PMCID: PMC5388407 DOI: 10.1093/nar/gkw1224] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 11/08/2016] [Accepted: 11/23/2016] [Indexed: 12/26/2022] Open
Abstract
In Saccharomyces cerevisiae generation of export-competent mRNPs terminates the nuclear phase of the gene expression pathway and facilitates transport to the cytoplasm for translation. Nab2 functions in this process to control both mRNP compaction that facilitates movement through nuclear pore complexes and the length of transcript poly(A) tails. Nab2 has a modular structure that includes seven CCCH Zn fingers that bind to A-rich RNAs and fingers 5–7 are critical for these functions. Here, we demonstrate, using both biophysical and structural methods, that binding A11G RNA induces dimerization of Zn fingers 5–7 mediated by the novel spatial arrangement of the fingers promoting each RNA chain binding two protein chains. The dimerization of Nab2 induced by RNA binding provides a basis for understanding its function in both poly(A) tail length regulation and in the compaction of mature transcripts to facilitate nuclear export.
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Affiliation(s)
- Shintaro Aibara
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - James M B Gordon
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - Anja S Riesterer
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - Stephen H McLaughlin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
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32
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Kubitscheck U, Siebrasse JP. Kinetics of transport through the nuclear pore complex. Semin Cell Dev Biol 2017; 68:18-26. [PMID: 28676422 DOI: 10.1016/j.semcdb.2017.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/23/2017] [Indexed: 01/06/2023]
Abstract
Single molecule microscopy techniques allow to visualize the translocation of single transport receptors and cargo molecules or particles through nuclear pore complexes. These data indicate that cargo molecule import into the nucleus takes less than 10ms and nuclear export of messenger RNA (mRNA) particles takes 50-350ms, up to several seconds for extremely bulky particles. This review summarizes and discusses experimental results on transport of nuclear transport factor 2 (NTF2), importin β and mRNA particles. Putative regulatory functions of importin β for the NPC transport mechanism and the RNA helicase Dbp5 for mRNA export kinetics are discussed.
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Affiliation(s)
- Ulrich Kubitscheck
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich Wilhelms-University Bonn, Wegeler Str. 12, D-53115 Bonn, Germany.
| | - Jan-Peter Siebrasse
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich Wilhelms-University Bonn, Wegeler Str. 12, D-53115 Bonn, Germany
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33
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Björk P, Wieslander L. Integration of mRNP formation and export. Cell Mol Life Sci 2017; 74:2875-2897. [PMID: 28314893 PMCID: PMC5501912 DOI: 10.1007/s00018-017-2503-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
Expression of protein-coding genes in eukaryotes relies on the coordinated action of many sophisticated molecular machineries. Transcription produces precursor mRNAs (pre-mRNAs) and the active gene provides an environment in which the pre-mRNAs are processed, folded, and assembled into RNA–protein (RNP) complexes. The dynamic pre-mRNPs incorporate the growing transcript, proteins, and the processing machineries, as well as the specific protein marks left after processing that are essential for export and the cytoplasmic fate of the mRNPs. After release from the gene, the mRNPs move by diffusion within the interchromatin compartment, making up pools of mRNPs. Here, splicing and polyadenylation can be completed and the mRNPs recruit the major export receptor NXF1. Export competent mRNPs interact with the nuclear pore complex, leading to export, concomitant with compositional and conformational changes of the mRNPs. We summarize the integrated nuclear processes involved in the formation and export of mRNPs.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Lars Wieslander
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
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34
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Becker E, Com E, Lavigne R, Guilleux MH, Evrard B, Pineau C, Primig M. The protein expression landscape of mitosis and meiosis in diploid budding yeast. J Proteomics 2017; 156:5-19. [DOI: 10.1016/j.jprot.2016.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/14/2016] [Accepted: 12/26/2016] [Indexed: 12/12/2022]
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35
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Dayan IE, Arga KY, Ulgen KO. Multiomics Approach to Novel Therapeutic Targets for Cancer and Aging-Related Diseases: Role of Sld7 in Yeast Aging Network. ACTA ACUST UNITED AC 2017; 21:100-113. [DOI: 10.1089/omi.2016.0157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Irem E. Dayan
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey
| | | | - Kutlu O. Ulgen
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey
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36
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Heinrich S, Derrer CP, Lari A, Weis K, Montpetit B. Temporal and spatial regulation of mRNA export: Single particle RNA-imaging provides new tools and insights. Bioessays 2017; 39. [PMID: 28052353 DOI: 10.1002/bies.201600124] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The transport of messenger RNAs (mRNAs) from the nucleus to cytoplasm is an essential step in the gene expression program of all eukaryotes. Recent technological advances in the areas of RNA-labeling, microscopy, and sequencing are leading to novel insights about mRNA biogenesis and export. This includes quantitative single molecule imaging (SMI) of RNA molecules in live cells, which is providing knowledge of the spatial and temporal dynamics of the export process. As this information becomes available, it leads to new questions, the reinterpretation of previous findings, and revised models of mRNA export. In this review, we will briefly highlight some of these recent findings and discuss how live cell SMI approaches may be used to further our current understanding of mRNA export and gene expression.
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Affiliation(s)
| | | | - Azra Lari
- Department of Cell Biology, University of Alberta, Edmonton, Canada
| | - Karsten Weis
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Canada.,Department of Viticulture and Enology, University of California, Davis, CA, USA
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37
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Popova VV, Glukhova AA, Georgieva SG, Kopytova DV. Interactions of the TREX-2 complex with mRNP particle of β-tubulin 56D gene. Mol Biol 2016. [DOI: 10.1134/s0026893316060157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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38
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Mitchell SF, Parker R. Identification of Endogenous mRNA-Binding Proteins in Yeast Using Crosslinking and PolyA Enrichment. Methods Mol Biol 2016; 1421:153-63. [PMID: 26965264 DOI: 10.1007/978-1-4939-3591-8_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The maturation, localization, stability, and translation of messenger RNAs (mRNAs) are regulated by a wide variety of mRNA-binding proteins. Identification of the complete set of mRNA-binding proteins is a key step in understanding the regulation of gene expression. Herein, we describe a method for identifying yeast mRNA-binding proteins in a systematic manner using UV crosslinking, purification of polyA(+) mRNAs under denaturing conditions, and mass spectrometry to identify covalently bound proteins.
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Affiliation(s)
- Sarah F Mitchell
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado Boulder, Jennie Smoly Caruthers Biotech Bldg., 3415 Colorado Avenue, Boulder, CO, 80303, USA.
| | - Roy Parker
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado Boulder, Jennie Smoly Caruthers Biotech Bldg., 3415 Colorado Avenue, Boulder, CO, 80303, USA
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39
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Lucas C, Ferreira C, Cazzanelli G, Franco-Duarte R, Tulha J, Roelink H, Conway SJ. Yeast Gup1(2) Proteins Are Homologues of the Hedgehog Morphogens Acyltransferases HHAT(L): Facts and Implications. J Dev Biol 2016; 4:E33. [PMID: 29615596 PMCID: PMC5831804 DOI: 10.3390/jdb4040033] [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: 07/01/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 12/16/2022] Open
Abstract
In multiple tissues, the Hedgehog secreted morphogen activates in the receiving cells a pathway involved in cell fate, proliferation and differentiation in the receiving cells. This pathway is particularly important during embryogenesis. The protein HHAT (Hedgehog O-acyltransferase) modifies Hh morphogens prior to their secretion, while HHATL (Hh O-acyltransferase-like) negatively regulates the pathway. HHAT and HHATL are homologous to Saccharomyces cerevisiae Gup2 and Gup1, respectively. In yeast, Gup1 is associated with a high number and diversity of biological functions, namely polarity establishment, secretory/endocytic pathway functionality, vacuole morphology and wall and membrane composition, structure and maintenance. Phenotypes underlying death, morphogenesis and differentiation are also included. Paracrine signalling, like the one promoted by the Hh pathway, has not been shown to occur in microbial communities, despite the fact that large aggregates of cells like biofilms or colonies behave as proto-tissues. Instead, these have been suggested to sense the population density through the secretion of quorum-sensing chemicals. This review focuses on Gup1/HHATL and Gup2/HHAT proteins. We review the functions and physiology associated with these proteins in yeasts and higher eukaryotes. We suggest standardisation of the presently chaotic Gup-related nomenclature, which includes KIAA117, c3orf3, RASP, Skinny, Sightless and Central Missing, in order to avoid the disclosure of otherwise unnoticed information.
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Affiliation(s)
- Cândida Lucas
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
| | - Célia Ferreira
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK;
| | - Giulia Cazzanelli
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
| | - Ricardo Franco-Duarte
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
| | - Joana Tulha
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
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40
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The Evolutionarily-conserved Polyadenosine RNA Binding Protein, Nab2, Cooperates with Splicing Machinery to Regulate the Fate of pre-mRNA. Mol Cell Biol 2016; 36:2697-2714. [PMID: 27528618 PMCID: PMC5064217 DOI: 10.1128/mcb.00402-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Numerous RNA binding proteins are deposited onto an mRNA transcript to modulate post-transcriptional processing events ensuring proper mRNA maturation. Defining the interplay between RNA binding proteins that couple mRNA biogenesis events is crucial for understanding how gene expression is regulated. To explore how RNA binding proteins control mRNA processing, we investigated a role for the evolutionarily conserved polyadenosine RNA binding protein, Nab2, in mRNA maturation within the nucleus. This work reveals that nab2 mutant cells accumulate intron-containing pre-mRNA in vivo We extend this analysis to identify genetic interactions between mutant alleles of nab2 and genes encoding the splicing factor, MUD2, and the RNA exosome, RRP6, with in vivo consequences of altered pre-mRNA splicing and poly(A) tail length control. As further evidence linking Nab2 proteins to splicing, an unbiased proteomic analysis of vertebrate Nab2, ZC3H14, identifies physical interactions with numerous components of the spliceosome. We validated the interaction between ZC3H14 and U2AF2/U2AF65 Taking all the findings into consideration, we present a model where Nab2/ZC3H14 interacts with spliceosome components to allow proper coupling of splicing with subsequent mRNA processing steps contributing to a kinetic proofreading step that allows properly processed mRNA to exit the nucleus and escape Rrp6-dependent degradation.
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41
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Abstract
The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2.
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42
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Musser SM, Grünwald D. Deciphering the Structure and Function of Nuclear Pores Using Single-Molecule Fluorescence Approaches. J Mol Biol 2016; 428:2091-119. [PMID: 26944195 DOI: 10.1016/j.jmb.2016.02.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 01/05/2016] [Accepted: 02/17/2016] [Indexed: 01/06/2023]
Abstract
Due to its central role in macromolecular trafficking and nucleocytoplasmic information transfer, the nuclear pore complex (NPC) has been studied in great detail using a wide spectrum of methods. Consequently, many aspects of its architecture, general function, and role in the life cycle of a cell are well understood. Over the last decade, fluorescence microscopy methods have enabled the real-time visualization of single molecules interacting with and transiting through the NPC, allowing novel questions to be examined with nanometer precision. While initial single-molecule studies focused primarily on import pathways using permeabilized cells, it has recently proven feasible to investigate the export of mRNAs in living cells. Single-molecule assays can address questions that are difficult or impossible to answer by other means, yet the complexity of nucleocytoplasmic transport requires that interpretation be based on a firm genetic, biochemical, and structural foundation. Moreover, conceptually simple single-molecule experiments remain technically challenging, particularly with regard to signal intensity, signal-to-noise ratio, and the analysis of noise, stochasticity, and precision. We discuss nuclear transport issues recently addressed by single-molecule microscopy, evaluate the limits of existing assays and data, and identify open questions for future studies. We expect that single-molecule fluorescence approaches will continue to be applied to outstanding nucleocytoplasmic transport questions, and that the approaches developed for NPC studies are extendable to additional complex systems and pathways within cells.
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Affiliation(s)
- Siegfried M Musser
- Department of Molecular and Cellular Medicine, College of Medicine, The Texas A&M Health Science Center, 1114 TAMU, College Station, TX 77843, USA.
| | - David Grünwald
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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43
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Rahaman SNA, Mat Yusop J, Mohamed-Hussein ZA, Ho KL, Teh AH, Waterman J, Ng CL. Cloning, expression, purification, crystallization and X-ray crystallographic analysis of recombinant human C1ORF123 protein. Acta Crystallogr F Struct Biol Commun 2016; 72:207-13. [PMID: 26919524 PMCID: PMC4774879 DOI: 10.1107/s2053230x16002016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/02/2016] [Indexed: 01/17/2023] Open
Abstract
C1ORF123 is a human hypothetical protein found in open reading frame 123 of chromosome 1. The protein belongs to the DUF866 protein family comprising eukaryote-conserved proteins with unknown function. Recent proteomic and bioinformatic analyses identified the presence of C1ORF123 in brain, frontal cortex and synapses, as well as its involvement in endocrine function and polycystic ovary syndrome (PCOS), indicating the importance of its biological role. In order to provide a better understanding of the biological function of the human C1ORF123 protein, the characterization and analysis of recombinant C1ORF123 (rC1ORF123), including overexpression and purification, verification by mass spectrometry and a Western blot using anti-C1ORF123 antibodies, crystallization and X-ray diffraction analysis of the protein crystals, are reported here. The rC1ORF123 protein was crystallized by the hanging-drop vapor-diffusion method with a reservoir solution comprised of 20% PEG 3350, 0.2 M magnesium chloride hexahydrate, 0.1 M sodium citrate pH 6.5. The crystals diffracted to 1.9 Å resolution and belonged to an orthorhombic space group with unit-cell parameters a = 59.32, b = 65.35, c = 95.05 Å. The calculated Matthews coefficient (VM) value of 2.27 Å(3) Da(-1) suggests that there are two molecules per asymmetric unit, with an estimated solvent content of 45.7%.
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Affiliation(s)
| | - Jastina Mat Yusop
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Zeti-Azura Mohamed-Hussein
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Aik-Hong Teh
- Centre for Chemical Biology, Universiti Sains Malaysia, 11900 Bayan Lepas, Penang, Malaysia
| | - Jitka Waterman
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
| | - Chyan Leong Ng
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
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44
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Björk P, Wieslander L. The Balbiani Ring Story: Synthesis, Assembly, Processing, and Transport of Specific Messenger RNA-Protein Complexes. Annu Rev Biochem 2015; 84:65-92. [PMID: 26034888 DOI: 10.1146/annurev-biochem-060614-034150] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Eukaryotic gene expression is the result of the integrated action of multimolecular machineries. These machineries associate with gene transcripts, often already nascent precursor messenger RNAs (pre-mRNAs). They rebuild the transcript and convey properties allowing the processed transcript, the mRNA, to be exported to the cytoplasm, quality controlled, stored, translated, and degraded. To understand these integrated processes, one must understand the temporal and spatial aspects of the fate of the gene transcripts in relation to interacting molecular machineries. Improved methodology is necessary to study gene expression in vivo for endogenous genes. A complementary approach is to study biological systems that provide exceptional experimental possibilities. We describe such a system, the Balbiani ring (BR) genes in polytene cells in the dipteran Chironomus tentans. The BR genes, along with their pre-mRNA-protein complexes (pre-mRNPs) and mRNA-protein complexes (mRNPs), allow the visualization of intact cell nuclei and enable analyses of where and when different molecular machineries associate with and act on the BR pre-mRNAs and mRNAs.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden;
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45
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Sloan KE, Gleizes PE, Bohnsack MT. Nucleocytoplasmic Transport of RNAs and RNA-Protein Complexes. J Mol Biol 2015; 428:2040-59. [PMID: 26434509 DOI: 10.1016/j.jmb.2015.09.023] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/26/2015] [Accepted: 09/28/2015] [Indexed: 12/15/2022]
Abstract
RNAs and ribonucleoprotein complexes (RNPs) play key roles in mediating and regulating gene expression. In eukaryotes, most RNAs are transcribed, processed and assembled with proteins in the nucleus and then either function in the cytoplasm or also undergo a cytoplasmic phase in their biogenesis. This compartmentalization ensures that sequential steps in gene expression and RNP production are performed in the correct order and it allows important quality control mechanisms that prevent the involvement of aberrant RNAs/RNPs in these cellular pathways. The selective exchange of RNAs/RNPs between the nucleus and cytoplasm is enabled by nuclear pore complexes, which function as gateways between these compartments. RNA/RNP transport is facilitated by a range of nuclear transport receptors and adaptors, which are specifically recruited to their cargos and mediate interactions with nucleoporins to allow directional translocation through nuclear pore complexes. While some transport factors are only responsible for the export/import of a certain class of RNA/RNP, others are multifunctional and, in the case of large RNPs, several export factors appear to work together to bring about export. Recent structural studies have revealed aspects of the mechanisms employed by transport receptors to enable specific cargo recognition, and genome-wide approaches have provided the first insights into the diverse composition of pre-mRNPs during export. Furthermore, the regulation of RNA/RNP export is emerging as an important means to modulate gene expression under stress conditions and in disease.
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Affiliation(s)
- Katherine E Sloan
- Institute for Molecular Biology, Goettingen University Medical Department, 37073 Goettingen, Germany
| | - Pierre-Emmanuel Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, UMR 5099, Université de Toulouse-Paul Sabatier, CNRS, Toulouse, France
| | - Markus T Bohnsack
- Institute for Molecular Biology, Goettingen University Medical Department, 37073 Goettingen, Germany; Goettingen Centre for Molecular Biosciences, Georg-August-University, 37075 Goettingen, Germany.
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46
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Polledo JM, Cervini G, Romaniuk MA, Cassola A. Interactions between RNA-binding proteins and P32 homologues in trypanosomes and human cells. Curr Genet 2015; 62:203-12. [PMID: 26385742 DOI: 10.1007/s00294-015-0519-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 12/25/2022]
Abstract
RNA-binding proteins (RBPs) are involved in many aspects of mRNA metabolism such as splicing, nuclear export, translation, silencing, and decay. To cope with these tasks, these proteins use specialized domains such as the RNA recognition motif (RRM), the most abundant and widely spread RNA-binding domain. Although this domain was first described as a dedicated RNA-binding moiety, current evidence indicates these motifs can also engage in direct protein-protein interactions. Here, we discuss recent evidence describing the interaction between the RRM of the trypanosomatid RBP UBP1 and P22, the homolog of the human multifunctional protein P32/C1QBP. Human P32 was also identified while performing a similar interaction screening using both RRMs of TDP-43, an RBP involved in splicing regulation and Amyotrophic Lateral Sclerosis. Furthermore, we show that this interaction is mediated by RRM1. The relevance of this interaction is discussed in the context of recent TDP-43 interactomic approaches that identified P32, and the numerous evidences supporting interactions between P32 and RBPs. Finally, we discuss the vast universe of interactions involving P32, supporting its role as a molecular chaperone regulating the function of its ligands.
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Affiliation(s)
- Juan Manuel Polledo
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina
| | - Gabriela Cervini
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina
| | - María Albertina Romaniuk
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina
| | - Alejandro Cassola
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina.
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47
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Mitchell SF, Parker R. In vivo cross-linking followed by polyA enrichment to identify yeast mRNA binding proteins. Methods Mol Biol 2015; 1259:35-47. [PMID: 25579578 DOI: 10.1007/978-1-4939-2214-7_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
mRNA binding proteins regulate gene expression by controlling the processing, localization, decay, and translation of messenger RNAs (mRNAs). To fully understand this process, it is necessary to identify the complete set of mRNA binding proteins. This work describes a method for the systematic identification of yeast mRNA binding proteins. This method applies in vivo UV cross-linking, affinity pull-down of polyA(+) mRNAs, and analysis by mass spectrometry to identify proteins that directly bind to mRNAs.
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Affiliation(s)
- Sarah F Mitchell
- Department of Chemistry and Biochemistry, University of Colorado Boulder, JSCBB Room B450, 3415 Colorado Ave, UCB 596, Boulder, CO, 80303, USA,
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48
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Low-Rank and Sparse Matrix Decomposition for Genetic Interaction Data. BIOMED RESEARCH INTERNATIONAL 2015; 2015:573956. [PMID: 26273633 PMCID: PMC4529927 DOI: 10.1155/2015/573956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/13/2015] [Indexed: 11/28/2022]
Abstract
Background. Epistatic miniarray profile (EMAP) studies have enabled the mapping of large-scale genetic interaction networks and generated large amounts of data in model organisms. One approach to analyze EMAP data is to identify gene modules with densely interacting genes. In addition, genetic interaction score (S score) reflects the degree of synergizing or mitigating effect of two mutants, which is also informative. Statistical approaches that exploit both modularity and the pairwise interactions may provide more insight into the underlying biology. However, the high missing rate in EMAP data hinders the development of such approaches. To address the above problem, we adopted the matrix decomposition methodology “low-rank and sparse decomposition” (LRSDec) to decompose EMAP data matrix into low-rank part and sparse part. Results. LRSDec has been demonstrated as an effective technique for analyzing EMAP data. We applied a synthetic dataset and an EMAP dataset studying RNA-related processes in Saccharomyces cerevisiae. Global views of the genetic cross talk between different RNA-related protein complexes and processes have been structured, and novel functions of genes have been predicted.
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49
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Oeffinger M, Montpetit B. Emerging properties of nuclear RNP biogenesis and export. Curr Opin Cell Biol 2015; 34:46-53. [PMID: 25938908 DOI: 10.1016/j.ceb.2015.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/23/2015] [Accepted: 04/14/2015] [Indexed: 01/02/2023]
Abstract
RNA biology has recently seen an explosion of data due to advances in RNA sequencing, proteomic, and RNA imaging technologies. In this review, we highlight progress that has been made using these approaches in the area of nuclear RNP biogenesis and export. Excitingly, the ability to collect quantitative data at the 'omics' scale combined with measurements of transcription, decay, and transport kinetics is providing the information needed to address RNP biogenesis at a systems level. We believe this to be a necessary and critical next step that will lead to a better understanding of how RNP quality, diversity, and fate emerge from a defined set of nuclear RNP assembly and maturation steps.
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Affiliation(s)
- Marlene Oeffinger
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7; Département de biochimie et médicine moléculaire, Université de Montréal, Montréal, Québec, Canada H3T 1J4; Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada H3A 1A3.
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, 5-14 Medical Sciences Building, Edmonton, Alberta, Canada T6G 2H7.
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50
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Nuclear export of messenger RNA. Genes (Basel) 2015; 6:163-84. [PMID: 25836925 PMCID: PMC4488659 DOI: 10.3390/genes6020163] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 11/29/2022] Open
Abstract
Transport of messenger RNA (mRNA) from the nucleus to the cytoplasm is an essential step of eukaryotic gene expression. In the cell nucleus, a precursor mRNA undergoes a series of processing steps, including capping at the 5' ends, splicing and cleavage/polyadenylation at the 3' ends. During this process, the mRNA associates with a wide variety of proteins, forming a messenger ribonucleoprotein (mRNP) particle. Association with factors involved in nuclear export also occurs during transcription and processing, and thus nuclear export is fully integrated into mRNA maturation. The coupling between mRNA maturation and nuclear export is an important mechanism for providing only fully functional and competent mRNA to the cytoplasmic translational machinery, thereby ensuring accuracy and swiftness of gene expression. This review describes the molecular mechanism of nuclear mRNA export mediated by the principal transport factors, including Tap-p15 and the TREX complex.
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