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Liu Y, Park JM, Lim S, Duan R, Lee DY, Choi D, Choi DK, Rhie BH, Cho SY, Ryu HY, Ahn SH. Tho2-mediated escort of Nrd1 regulates the expression of aging-related genes. Aging Cell 2024:e14203. [PMID: 38769776 DOI: 10.1111/acel.14203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/22/2024] Open
Abstract
The relationship between aging and RNA biogenesis and trafficking is attracting growing interest, yet the precise mechanisms are unknown. The THO complex is crucial for mRNA cotranscriptional maturation and export. Herein, we report that the THO complex is closely linked to the regulation of lifespan. Deficiencies in Hpr1 and Tho2, components of the THO complex, reduced replicative lifespan (RLS) and are linked to a novel Sir2-independent RLS control pathway. Although transcript sequestration in hpr1Δ or tho2Δ mutants was countered by exosome component Rrp6, loss of this failed to mitigate RLS defects in hpr1Δ. However, RLS impairment in hpr1Δ or tho2Δ was counteracted by the additional expression of Nrd1-specific mutants that interacted with Rrp6. This effect relied on the interaction of Nrd1, a transcriptional regulator of aging-related genes, including ribosome biogenesis or RNA metabolism genes, with RNA polymerase II. Nrd1 overexpression reduced RLS in a Tho2-dependent pathway. Intriguingly, Tho2 deletion mirrored Nrd1 overexpression effects by inducing arbitrary Nrd1 chromatin binding. Furthermore, our genome-wide ChIP-seq analysis revealed an increase in the recruitment of Nrd1 to translation-associated genes, known to be related to aging, upon Tho2 loss. Taken together, these findings underscore the importance of Tho2-mediated Nrd1 escorting in the regulation of lifespan pathway through transcriptional regulation of aging-related genes.
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Affiliation(s)
- Yan Liu
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Republic of Korea
| | - Jeong-Min Park
- KNU LAMP Research Center, KNU Institute of Basic Sciences, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Suji Lim
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Republic of Korea
| | - Ruxin Duan
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Republic of Korea
| | - Do Yoon Lee
- KNU LAMP Research Center, KNU Institute of Basic Sciences, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Dahee Choi
- KNU LAMP Research Center, KNU Institute of Basic Sciences, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Dong Kyu Choi
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Byung-Ho Rhie
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Republic of Korea
| | - Soo Young Cho
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Republic of Korea
| | - Hong-Yeoul Ryu
- KNU LAMP Research Center, KNU Institute of Basic Sciences, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Seong Hoon Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Republic of Korea
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Ghate NB, Nadkarni KS, Barik GK, Tat SS, Sahay O, Santra MK. Histone ubiquitination: Role in genome integrity and chromatin organization. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195044. [PMID: 38763317 DOI: 10.1016/j.bbagrm.2024.195044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/21/2024]
Abstract
Maintenance of genome integrity is a precise but tedious and complex job for the cell. Several post-translational modifications (PTMs) play vital roles in maintaining the genome integrity. Although ubiquitination is one of the most crucial PTMs, which regulates the localization and stability of the nonhistone proteins in various cellular and developmental processes, ubiquitination of the histones is a pivotal epigenetic event critically regulating chromatin architecture. In addition to genome integrity, importance of ubiquitination of core histones (H2A, H2A, H3, and H4) and linker histone (H1) have been reported in several cellular processes. However, the complex interplay of histone ubiquitination and other PTMs, as well as the intricate chromatin architecture and dynamics, pose a significant challenge to unravel how histone ubiquitination safeguards genome stability. Therefore, further studies are needed to elucidate the interactions between histone ubiquitination and other PTMs, and their role in preserving genome integrity. Here, we review all types of histone ubiquitinations known till date in maintaining genomic integrity during transcription, replication, cell cycle, and DNA damage response processes. In addition, we have also discussed the role of histone ubiquitination in regulating other histone PTMs emphasizing methylation and acetylation as well as their potential implications in chromatin architecture. Further, we have also discussed the involvement of deubiquitination enzymes (DUBs) in controlling histone ubiquitination in modulating cellular processes.
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Affiliation(s)
- Nikhil Baban Ghate
- Cancer Biology Division, National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India.
| | - Kaustubh Sanjay Nadkarni
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Ganesh Kumar Barik
- Cancer Biology Division, National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India; Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Sharad Shriram Tat
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Osheen Sahay
- Cancer Biology Division, National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India; Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Manas Kumar Santra
- Cancer Biology Division, National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India.
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3
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Vdovina YA, Kurshakova MM, Georgieva SG, Kopytova DV. PCID2 Subunit of the Drosophila TREX-2 Complex Has Two RNA-Binding Regions. Curr Issues Mol Biol 2023; 45:5662-5676. [PMID: 37504273 PMCID: PMC10378293 DOI: 10.3390/cimb45070357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023] Open
Abstract
Drosophila PCID2 is a subunit of the TREX-2 mRNA nuclear export complex. Although the complex has long been studied in eukaryotes, it is still unclear how TREX-2 interacts with mRNA in multicellular organisms. Here, the interaction between Drosophila PCID2 and the ras2 RNA was studied by EMSA. We show that the C-terminal region of the WH domain of PCID2 specifically binds the 3'-noncoding region of the ras2 RNA. While the same region of PCID2 interacts with the Xmas-2 subunit of the TREX-2 complex, PCID2 interacts with RNA independently of Xmas-2. An additional RNA-binding region (M region) was identified in the N-terminal part of the PCI domain and found to bind RNA nonspecifically. Point mutations of evolutionarily conserved amino acid residues in this region completely abolish the PCID2-RNA interaction, while a deletion of the C-terminal domain only partly decreases it. Thus, the specific interaction of PCID2 with RNA requires nonspecific PCID2-RNA binding.
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Affiliation(s)
- Yulia A Vdovina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Maria M Kurshakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Sofia G Georgieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Daria V Kopytova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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4
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Sending the message: specialized RNA export mechanisms in trypanosomes. Trends Parasitol 2022; 38:854-867. [PMID: 36028415 PMCID: PMC9894534 DOI: 10.1016/j.pt.2022.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 02/04/2023]
Abstract
Export of RNA from the nucleus is essential for all eukaryotic cells and has emerged as a major step in the control of gene expression. mRNA molecules are required to complete a complex series of processing events and pass a quality control system to protect the cytoplasm from the translation of aberrant proteins. Many of these events are highly conserved across eukaryotes, reflecting their ancient origin, but significant deviation from a canonical pathway as described from animals and fungi has emerged in the trypanosomatids. With significant implications for the mechanisms that control gene expression and hence differentiation, responses to altered environments and fitness as a parasite, these deviations may also reveal additional, previously unsuspected, mRNA export pathways.
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5
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Dutta S, Polavaram NS, Islam R, Bhattacharya S, Bodas S, Mayr T, Roy S, Albala SAY, Toma MI, Darehshouri A, Borkowetz A, Conrad S, Fuessel S, Wirth M, Baretton GB, Hofbauer LC, Ghosh P, Pienta KJ, Klinkebiel DL, Batra SK, Muders MH, Datta K. Neuropilin-2 regulates androgen-receptor transcriptional activity in advanced prostate cancer. Oncogene 2022; 41:3747-3760. [PMID: 35754042 PMCID: PMC9979947 DOI: 10.1038/s41388-022-02382-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 06/03/2022] [Accepted: 06/10/2022] [Indexed: 01/22/2023]
Abstract
Aberrant transcriptional activity of androgen receptor (AR) is one of the dominant mechanisms for developing of castration-resistant prostate cancer (CRPC). Analyzing AR-transcriptional complex related to CRPC is therefore important towards understanding the mechanism of therapy resistance. While studying its mechanism, we observed that a transmembrane protein called neuropilin-2 (NRP2) plays a contributory role in forming a novel AR-transcriptional complex containing nuclear pore proteins. Using immunogold electron microscopy, high-resolution confocal microscopy, chromatin immunoprecipitation, proteomics, and other biochemical techniques, we delineated the molecular mechanism of how a specific splice variant of NRP2 becomes sumoylated upon ligand stimulation and translocates to the inner nuclear membrane. This splice variant of NRP2 then stabilizes the complex between AR and nuclear pore proteins to promote CRPC specific gene expression. Both full-length and splice variants of AR have been identified in this specific transcriptional complex. In vitro cell line-based assays indicated that depletion of NRP2 not only destabilizes the AR-nuclear pore protein interaction but also inhibits the transcriptional activities of AR. Using an in vivo bone metastasis model, we showed that the inhibition of NRP2 led to the sensitization of CRPC cells toward established anti-AR therapies such as enzalutamide. Overall, our finding emphasize the importance of combinatorial inhibition of NRP2 and AR as an effective therapeutic strategy against treatment refractory prostate cancer.
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Affiliation(s)
- Samikshan Dutta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.
| | - Navatha Shree Polavaram
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Ridwan Islam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sreyashi Bhattacharya
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sanika Bodas
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Thomas Mayr
- Rudolf Becker Laboratory for Prostate Cancer Research, Medical Faculty, University of Bonn, Germany,Institute of Pathology, Medical Faculty, University of Bonn, Germany,Institute of Pathology, Technische Universitaet Dresden, Dresden, Germany
| | - Sohini Roy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Marieta I. Toma
- Institute of Pathology, Medical Faculty, University of Bonn, Germany,Institute of Pathology, Technische Universitaet Dresden, Dresden, Germany
| | - Anza Darehshouri
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Angelika Borkowetz
- Department of Urology, Technische Universitaet Dresden, Dresden, Germany
| | - Stefanie Conrad
- Division of Endocrinology and Metabolic Bone Diseases, Department of Medicine III, Technische Universitaet Dresden, Dresden, Germany,Center for Healthy Aging, Technische Universitaet Dresden, Dresden, Germany
| | - Susanne Fuessel
- Department of Urology, Technische Universitaet Dresden, Dresden, Germany
| | - Manfred Wirth
- Department of Urology, Technische Universitaet Dresden, Dresden, Germany
| | - Gustavo B. Baretton
- Institute of Pathology, Technische Universitaet Dresden, Dresden, Germany,German Cancer Consortium (DKTK), partner site Dresden and German Research Center (DKFZ), Heidelberg, Germany,Tumor and Normal Tissue Bank of the University Cancer Center (UCC), University Hospital and Faculty of Medicine, Technische Universitaet Dresden, Germany
| | - Lorenz C. Hofbauer
- Division of Endocrinology and Metabolic Bone Diseases, Department of Medicine III, Technische Universitaet Dresden, Dresden, Germany,Center for Healthy Aging, Technische Universitaet Dresden, Dresden, Germany,German Cancer Consortium (DKTK), partner site Dresden and German Research Center (DKFZ), Heidelberg, Germany
| | - Paramita Ghosh
- Department of Biochemistry and Molecular Medicine, University of California Davis
| | - Kenneth J. Pienta
- The Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David L Klinkebiel
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michael H. Muders
- Rudolf Becker Laboratory for Prostate Cancer Research, Medical Faculty, University of Bonn, Germany,Institute of Pathology, Medical Faculty, University of Bonn, Germany,Institute of Pathology, Technische Universitaet Dresden, Dresden, Germany
| | - Kaustubh Datta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.
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6
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Lim S, Liu Y, Rhie BH, Kim C, Ryu HY, Ahn SH. Sus1 maintains a normal lifespan through regulation of TREX-2 complex-mediated mRNA export. Aging (Albany NY) 2022; 14:4990-5012. [PMID: 35771153 PMCID: PMC9271307 DOI: 10.18632/aging.204146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
Eukaryotic gene expression requires multiple cellular events, including transcription and RNA processing and transport. Sus1, a common subunit in both the Spt-Ada-Gcn5 acetyltransferase (SAGA) and transcription and export complex-2 (TREX-2) complexes, is a key factor in coupling transcription activation to mRNA nuclear export. Here, we report that the SAGA DUB module and TREX-2 distinctly regulate yeast replicative lifespan in a Sir2-dependent and -independent manner, respectively. The growth and lifespan impaired by SUS1 loss depend on TREX-2 but not on the SAGA DUB module. Notably, an increased dose of the mRNA export factors Mex67 and Dbp5 rescues the growth defect, shortened lifespan, and nuclear accumulation of poly(A)+ RNA in sus1Δ cells, suggesting that boosting the mRNA export process restores the mRNA transport defect and the growth and lifespan damage in sus1Δ cells. Moreover, Sus1 is required for the proper association of Mex67 and Dbp5 with the nuclear rim. Together, these data indicate that Sus1 links transcription and mRNA nuclear export to the lifespan control pathway, suggesting that prevention of an abnormal accumulation of nuclear RNA is necessary for maintenance of a normal lifespan.
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Affiliation(s)
- Suji Lim
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Yan Liu
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Byung-Ho Rhie
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Chun Kim
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Hong-Yeoul Ryu
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, College of National Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Seong Hoon Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
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7
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Park J, Hong J, Seok J, Hong H, Seo H, Kim KJ. Structural studies of a novel auxiliary-domain-containing phenylalanine hydroxylase from Bacillus cereus ATCC 14579. Acta Crystallogr D Struct Biol 2022; 78:586-598. [DOI: 10.1107/s2059798322002674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/08/2022] [Indexed: 11/11/2022] Open
Abstract
Phenylalanine hydroxylase (PAH), which belongs to the aromatic amino-acid hydroxylase family, is involved in protein synthesis and pyomelanine production through the hydroxylation of phenylalanine to tyrosine. In this study, the crystal structure of PAH from Bacillus cereus ATCC 14579 (BcPAH) with an additional 280 amino acids in the C-terminal region was determined. The structure of BcPAH consists of three distinct domains: a core domain with two additional inserted α-helices and two novel auxiliary domains: BcPAH-AD1 and BcPAH-AD2. Structural homologues of BcPAH-AD1 and BcPAH-AD2 are known to be involved in mRNA regulation and protein–protein interactions, and thus it was speculated that BcPAH might utilize the auxiliary domains for interaction with its partner proteins. Furthermore, phylogenetic tree analysis revealed that the three-domain PAHs, including BcPAH, are completely distinctive from both conventional prokaryotic PAHs and eukaryotic PAHs. Finally, biochemical studies of BcPAH showed that BcPAH-AD1 might be important for the structural integrity of the enzyme and that BcPAH-AD2 is related to enzyme stability and/or activity. Investigations into the intracellular functions of the two auxiliary domains and the relationship between these functions and the activity of PAH are required.
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8
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Goswami R, Bello AI, Bean J, Costanzo KM, Omer B, Cornelio-Parra D, Odah R, Ahluwalia A, Allan SK, Nguyen N, Shores T, Aziz NA, Mohan RD. The Molecular Basis of Spinocerebellar Ataxia Type 7. Front Neurosci 2022; 16:818757. [PMID: 35401096 PMCID: PMC8987156 DOI: 10.3389/fnins.2022.818757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/07/2022] [Indexed: 11/19/2022] Open
Abstract
Spinocerebellar ataxia (SCA) type 7 (SCA7) is caused by a CAG trinucleotide repeat expansion in the ataxin 7 (ATXN7) gene, which results in polyglutamine expansion at the amino terminus of the ATXN7 protein. Although ATXN7 is expressed widely, the best characterized symptoms of SCA7 are remarkably tissue specific, including blindness and degeneration of the brain and spinal cord. While it is well established that ATXN7 functions as a subunit of the Spt Ada Gcn5 acetyltransferase (SAGA) chromatin modifying complex, the mechanisms underlying SCA7 remain elusive. Here, we review the symptoms of SCA7 and examine functions of ATXN7 that may provide further insights into its pathogenesis. We also examine phenotypes associated with polyglutamine expanded ATXN7 that are not considered symptoms of SCA7.
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Affiliation(s)
- Rituparna Goswami
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Abudu I. Bello
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Joe Bean
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Kara M. Costanzo
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Bwaar Omer
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Dayanne Cornelio-Parra
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Revan Odah
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Amit Ahluwalia
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Shefaa K. Allan
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Nghi Nguyen
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Taylor Shores
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - N. Ahmad Aziz
- Population Health Sciences, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Ryan D. Mohan
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
- *Correspondence: Ryan D. Mohan,
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9
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Aguilera P, Dubarry M, Hardy J, Lisby M, Simon MN, Géli V. Telomeric C-circles localize at nuclear pore complexes in Saccharomyces cerevisiae. EMBO J 2022; 41:e108736. [PMID: 35147992 PMCID: PMC8922269 DOI: 10.15252/embj.2021108736] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 11/09/2022] Open
Abstract
As in human cells, yeast telomeres can be maintained in cells lacking telomerase activity by recombination-based mechanisms known as ALT (Alternative Lengthening of Telomeres). A hallmark of ALT human cancer cells are extrachromosomal telomeric DNA elements called C-circles, whose origin and function have remained unclear. Here, we show that extrachromosomal telomeric C-circles in yeast can be detected shortly after senescence crisis and concomitantly with the production of survivors arising from "type II" recombination events. We uncover that C-circles bind to the nuclear pore complex (NPC) and to the SAGA-TREX2 complex, similar to other non-centromeric episomal DNA. Disrupting the integrity of the SAGA/TREX2 complex affects both C-circle binding to NPCs and type II telomere recombination, suggesting that NPC tethering of C-circles facilitates formation and/or propagation of the long telomere repeats characteristic of type II survivors. Furthermore, we find that disruption of the nuclear diffusion barrier impairs type II recombination. These results support a model in which concentration of C-circles at NPCs benefits type II telomere recombination, highlighting the importance of spatial coordination in ALT-type mechanisms of telomere maintenance.
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Affiliation(s)
- Paula Aguilera
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Marion Dubarry
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Julien Hardy
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Marie-Noëlle Simon
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Vincent Géli
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
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10
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Zheleva A, Camino LP, Fernández-Fernández N, García-Rubio M, Askjaer P, García-Muse T, Aguilera A. THSC/TREX-2 deficiency causes replication stress and genome instability in Caenorhabditis elegans. J Cell Sci 2021; 134:jcs258435. [PMID: 34553761 PMCID: PMC10658913 DOI: 10.1242/jcs.258435] [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: 01/19/2021] [Accepted: 09/11/2021] [Indexed: 11/20/2022] Open
Abstract
Transcription is an essential process of DNA metabolism, yet it makes DNA more susceptible to DNA damage. THSC/TREX-2 is a conserved eukaryotic protein complex with a key role in mRNP biogenesis and maturation that prevents genome instability. One source of such instability is linked to transcription, as shown in yeast and human cells, but the underlying mechanism and whether this link is universal is still unclear. To obtain further insight into the putative role of the THSC/TREX-2 complex in genome integrity, we have used Caenorhabditis elegans mutants of the thp-1 and dss-1 components of THSC/TREX-2. These mutants show similar defective meiosis, DNA damage accumulation and activation of the DNA damage checkpoint. However, they differ from each other regarding replication defects, as determined by measuring dUTP incorporation in the germline. Interestingly, this specific thp-1 mutant phenotype can be partially rescued by overexpression of RNase H. Furthermore, both mutants show a mild increase in phosphorylation of histone H3 at Ser10 (H3S10P), a mark previously shown to be linked to DNA-RNA hybrid-mediated genome instability. These data support the view that both THSC/TREX-2 factors prevent transcription-associated DNA damage derived from DNA-RNA hybrid accumulation by separate means.
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Affiliation(s)
- Angelina Zheleva
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Lola P. Camino
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Nuria Fernández-Fernández
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - María García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Peter Askjaer
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Tatiana García-Muse
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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11
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Gunkel P, Iino H, Krull S, Cordes VC. ZC3HC1 Is a Novel Inherent Component of the Nuclear Basket, Resident in a State of Reciprocal Dependence with TPR. Cells 2021; 10:1937. [PMID: 34440706 PMCID: PMC8393659 DOI: 10.3390/cells10081937] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 11/16/2022] Open
Abstract
The nuclear basket (NB) scaffold, a fibrillar structure anchored to the nuclear pore complex (NPC), is regarded as constructed of polypeptides of the coiled-coil dominated protein TPR to which other proteins can bind without contributing to the NB's structural integrity. Here we report vertebrate protein ZC3HC1 as a novel inherent constituent of the NB, common at the nuclear envelopes (NE) of proliferating and non-dividing, terminally differentiated cells of different morphogenetic origin. Formerly described as a protein of other functions, we instead present the NB component ZC3HC1 as a protein required for enabling distinct amounts of TPR to occur NB-appended, with such ZC3HC1-dependency applying to about half the total amount of TPR at the NEs of different somatic cell types. Furthermore, pointing to an NB structure more complex than previously anticipated, we discuss how ZC3HC1 and the ZC3HC1-dependent TPR polypeptides could enlarge the NB's functional repertoire.
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Affiliation(s)
| | | | | | - Volker C. Cordes
- Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany; (P.G.); (H.I.); (S.K.)
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12
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Kron NS, Fieber LA. Co-expression analysis identifies neuro-inflammation as a driver of sensory neuron aging in Aplysia californica. PLoS One 2021; 16:e0252647. [PMID: 34116561 PMCID: PMC8195618 DOI: 10.1371/journal.pone.0252647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/20/2021] [Indexed: 01/08/2023] Open
Abstract
Aging of the nervous system is typified by depressed metabolism, compromised proteostasis, and increased inflammation that results in cognitive impairment. Differential expression analysis is a popular technique for exploring the molecular underpinnings of neural aging, but technical drawbacks of the methodology often obscure larger expression patterns. Co-expression analysis offers a robust alternative that allows for identification of networks of genes and their putative central regulators. In an effort to expand upon previous work exploring neural aging in the marine model Aplysia californica, we used weighted gene correlation network analysis to identify co-expression networks in a targeted set of aging sensory neurons in these animals. We identified twelve modules, six of which were strongly positively or negatively associated with aging. Kyoto Encyclopedia of Genes analysis and investigation of central module transcripts identified signatures of metabolic impairment, increased reactive oxygen species, compromised proteostasis, disrupted signaling, and increased inflammation. Although modules with immune character were identified, there was no correlation between genes in Aplysia that increased in expression with aging and the orthologous genes in oyster displaying long-term increases in expression after a virus-like challenge. This suggests anti-viral response is not a driver of Aplysia sensory neuron aging.
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Affiliation(s)
- N. S. Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
| | - L. A. Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
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13
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McCormack NM, Abera MB, Arnold ES, Gibbs RM, Martin SE, Buehler E, Chen YC, Chen L, Fischbeck KH, Burnett BG. A high-throughput genome-wide RNAi screen identifies modifiers of survival motor neuron protein. Cell Rep 2021; 35:109125. [PMID: 33979606 PMCID: PMC8679797 DOI: 10.1016/j.celrep.2021.109125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/17/2021] [Accepted: 04/22/2021] [Indexed: 11/28/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a debilitating neurological disorder marked by degeneration of spinal motor neurons and muscle atrophy. SMA results from mutations in survival motor neuron 1 (SMN1), leading to deficiency of survival motor neuron (SMN) protein. Current therapies increase SMN protein and improve patient survival but have variable improvements in motor function, making it necessary to identify complementary strategies to further improve disease outcomes. Here, we perform a genome-wide RNAi screen using a luciferase-based activity reporter and identify genes involved in regulating SMN gene expression, RNA processing, and protein stability. We show that reduced expression of Transcription Export complex components increases SMN levels through the regulation of nuclear/cytoplasmic RNA transport. We also show that the E3 ligase, Neurl2, works cooperatively with Mib1 to ubiquitinate and promote SMN degradation. Together, our screen uncovers pathways through which SMN expression is regulated, potentially revealing additional strategies to treat SMA. Treatments for spinal muscular atrophy aim to increase survival motor neuron (SMN) protein. Using a genome-wide RNAi screen, McCormack et al. identify modifiers of SMN expression, including genes that are involved in transcription regulation, RNA processing, and protein stability.
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Affiliation(s)
- Nikki M McCormack
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Mahlet B Abera
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Eveline S Arnold
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Rebecca M Gibbs
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Scott E Martin
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Eugen Buehler
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Yu-Chi Chen
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Lu Chen
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA.
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14
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Soffers JHM, Workman JL. The SAGA chromatin-modifying complex: the sum of its parts is greater than the whole. Genes Dev 2021; 34:1287-1303. [PMID: 33004486 PMCID: PMC7528701 DOI: 10.1101/gad.341156.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this review, Soffers and Workman discuss the initial discovery of the canonical SAGA complex, the subsequent studies that have shaped our view on the internal organization of its subunits into modules, and the latest structural work that visualizes the modules and provides insights into their function. There are many large protein complexes involved in transcription in a chromatin context. However, recent studies on the SAGA coactivator complex are generating new paradigms for how the components of these complexes function, both independently and in concert. This review highlights the initial discovery of the canonical SAGA complex 23 years ago, our evolving understanding of its modular structure and the relevance of its modular nature for its coactivator function in gene regulation.
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Affiliation(s)
- Jelly H M Soffers
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Jerry L Workman
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
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15
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Lee ES, Wolf EJ, Ihn SSJ, Smith HW, Emili A, Palazzo AF. TPR is required for the efficient nuclear export of mRNAs and lncRNAs from short and intron-poor genes. Nucleic Acids Res 2021; 48:11645-11663. [PMID: 33091126 PMCID: PMC7672458 DOI: 10.1093/nar/gkaa919] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/21/2020] [Accepted: 10/02/2020] [Indexed: 12/14/2022] Open
Abstract
While splicing has been shown to enhance nuclear export, it has remained unclear whether mRNAs generated from intronless genes use specific machinery to promote their export. Here, we investigate the role of the major nuclear pore basket protein, TPR, in regulating mRNA and lncRNA nuclear export in human cells. By sequencing mRNA from the nucleus and cytosol of control and TPR-depleted cells, we provide evidence that TPR is required for the efficient nuclear export of mRNAs and lncRNAs that are generated from short transcripts that tend to have few introns, and we validate this with reporter constructs. Moreover, in TPR-depleted cells reporter mRNAs generated from short transcripts accumulate in nuclear speckles and are bound to Nxf1. These observations suggest that TPR acts downstream of Nxf1 recruitment and may allow mRNAs to leave nuclear speckles and properly dock with the nuclear pore. In summary, our study provides one of the first examples of a factor that is specifically required for the nuclear export of intronless and intron-poor mRNAs and lncRNAs.
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Affiliation(s)
- Eliza S Lee
- University of Toronto, Department of Biochemistry, Canada
| | - Eric J Wolf
- University of Toronto, Department of Molecular Genetics, Canada
| | - Sean S J Ihn
- University of Toronto, Department of Biochemistry, Canada
| | | | - Andrew Emili
- University of Toronto, Department of Molecular Genetics, Canada.,Boston University School of Medicine, Department of Biochemistry, Boston, MA, USA
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16
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Abstract
The passage of mRNAs through the nuclear pores into the cytoplasm is essential in all eukaryotes. For regulation, mRNA export is tightly connected to the full machinery of nuclear mRNA processing, starting at transcription. Export competence of pre-mRNAs gradually increases by both transient and permanent interactions with multiple RNA processing and export factors. mRNA export is best understood in opisthokonts, with limited knowledge in plants and protozoa. Here, I review and compare nuclear mRNA processing and export between opisthokonts and Trypanosoma brucei. The parasite has many unusual features in nuclear mRNA processing, such as polycistronic transcription and trans-splicing. It lacks several nuclear complexes and nuclear-pore-associated proteins that in opisthokonts play major roles in mRNA export. As a consequence, trypanosome mRNA export control is not tight and export can even start co-transcriptionally. Whether trypanosomes regulate mRNA export at all, or whether leakage of immature mRNA to the cytoplasm is kept to a low level by a fast kinetics of mRNA processing remains to be investigated. mRNA export had to be present in the last common ancestor of eukaryotes. Trypanosomes are evolutionary very distant from opisthokonts and a comparison helps understanding the evolution of mRNA export.
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17
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SAC3B is a target of CML19, the centrin 2 of Arabidopsis thaliana. Biochem J 2020; 477:173-189. [PMID: 31860002 DOI: 10.1042/bcj20190674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/15/2023]
Abstract
Arabidopsis centrin 2, also known as calmodulin-like protein 19 (CML19), is a member of the EF-hand superfamily of calcium (Ca2+)-binding proteins. In addition to the notion that CML19 interacts with the nucleotide excision repair protein RAD4, CML19 was suggested to be a component of the transcription export complex 2 (TREX-2) by interacting with SAC3B. However, the molecular determinants of this interaction have remained largely unknown. Herein, we identified a CML19-binding site within the C-terminus of SAC3B and characterized the binding properties of the corresponding 26-residue peptide (SAC3Bp), which exhibits the hydrophobic triad centrin-binding motif in a reversed orientation (I8W4W1). Using a combination of spectroscopic and calorimetric experiments, we shed light on the SAC3Bp-CML19 complex structure in solution. We demonstrated that the peptide interacts not only with Ca2+-saturated CML19, but also with apo-CML19 to form a protein-peptide complex with a 1 : 1 stoichiometry. Both interactions involve hydrophobic and electrostatic contributions and include the burial of Trp residues of SAC3Bp. However, the peptide likely assumes different conformations upon binding to apo-CML19 or Ca2+-CML19. Importantly, the peptide dramatically increases the affinity for Ca2+ of CML19, especially of the C-lobe, suggesting that in vivo the protein would be Ca2+-saturated and bound to SAC3B even at resting Ca2+-levels. Our results, providing direct evidence that Arabidopsis SAC3B is a CML19 target and proposing that CML19 can bind to SAC3B through its C-lobe independent of a Ca2+ stimulus, support a functional role for these proteins in TREX-2 complex and mRNA export.
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18
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Tamura K. Nuclear pore complex-mediated gene expression in Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2020; 133:449-455. [PMID: 32170459 DOI: 10.1007/s10265-020-01177-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/08/2020] [Indexed: 05/20/2023]
Abstract
Nuclear pore complexes (NPCs) are large multi-protein complexes that control bidirectional trafficking of macromolecules between the nucleus and cytoplasm. This trafficking is highly regulated and participates in a considerably broader range of cellular activities, including defense responses against pathogens in plants. Recently, NPC is emerging as a platform to physically associate the underlying chromatin with the nuclear periphery, thus regulating chromatin structure and gene expression. For instance, NPC components have been shown to promote the formation of specific genomics loops, which is linked to transcriptional memory for rapid reactivation of genes. With newly developed techniques and tools, our insight in this area has been substantially advanced. This review summarizes recent works on the molecular function of NPC machinery as hubs for transcriptional regulation and compares systems between plant and non-plant organisms.
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Affiliation(s)
- Kentaro Tamura
- Department of Environmental and Life Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan.
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19
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An insight into structural plasticity and conformational transitions of transcriptional co-activator Sus1. PLoS One 2020; 15:e0229216. [PMID: 32134955 PMCID: PMC7058303 DOI: 10.1371/journal.pone.0229216] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 01/31/2020] [Indexed: 11/30/2022] Open
Abstract
RNA biogenesis and mRNA transport are an intricate process for every eukaryotic cell. SAGA, a transcriptional coactivator and TREX-2 are the two major complexes participate in this process. Sus1 is a transcription export factor and part of both the SAGA and the TREX-2 complex. The competitive exchange of Sus1 molecule between SAGA and TREX-2 complex modulates their function which is credited to structural plasticity of Sus1. Here, we portray the biophysical characterization of Sus1 from S. cerevisiae. The recombinant Sus1 is a α-helical structure which is stable at various pH conditions. We reported the α-helix to β-sheet transition at the low pH as well as at high pH. Sus1 showed 50% reduction in the fluorescence intensity at pH-2 as compared to native protein. The fluorescence studies demonstrated the unfolding of tertiary structure of the protein with variation in pH as compared to neutral pH. The same results were obtained in the ANS binding and acrylamide quenching studies. Similarly, the secondary structure of the Sus1 was found to be stable till 55% alcohol concentration while tertiary structure was stable up to 20% alcohol concentration. Further increase in the alcohol concentration destabilizes the secondary as well as tertiary structure. The 300 mM concentration of ammonium sulfate also stabilizes the secondary structure of the protein. The structural characterization of this protein is expected to unfold the process of the transportation of the mRNA with cooperation of different proteins.
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20
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Into the basket and beyond: the journey of mRNA through the nuclear pore complex. Biochem J 2020; 477:23-44. [DOI: 10.1042/bcj20190132] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/28/2019] [Accepted: 12/10/2019] [Indexed: 02/06/2023]
Abstract
The genetic information encoded in nuclear mRNA destined to reach the cytoplasm requires the interaction of the mRNA molecule with the nuclear pore complex (NPC) for the process of mRNA export. Numerous proteins have important roles in the transport of mRNA out of the nucleus. The NPC embedded in the nuclear envelope is the port of exit for mRNA and is composed of ∼30 unique proteins, nucleoporins, forming the distinct structures of the nuclear basket, the pore channel and cytoplasmic filaments. Together, they serve as a rather stationary complex engaged in mRNA export, while a variety of soluble protein factors dynamically assemble on the mRNA and mediate the interactions of the mRNA with the NPC. mRNA export factors are recruited to and dissociate from the mRNA at the site of transcription on the gene, during the journey through the nucleoplasm and at the nuclear pore at the final stages of export. In this review, we present the current knowledge derived from biochemical, molecular, structural and imaging studies, to develop a high-resolution picture of the many events that culminate in the successful passage of the mRNA out of the nucleus.
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21
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Martín‐Expósito M, Gas M, Mohamad N, Nuño‐Cabanes C, Tejada‐Colón A, Pascual‐García P, de la Fuente L, Chaves‐Arquero B, Merran J, Corden J, Conesa A, Pérez‐Cañadillas JM, Bravo J, Rodríguez‐Navarro S. Mip6 binds directly to the Mex67 UBA domain to maintain low levels of Msn2/4 stress-dependent mRNAs. EMBO Rep 2019; 20:e47964. [PMID: 31680439 PMCID: PMC6893359 DOI: 10.15252/embr.201947964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 08/30/2019] [Accepted: 09/11/2019] [Indexed: 11/09/2022] Open
Abstract
RNA-binding proteins (RBPs) participate in all steps of gene expression, underscoring their potential as regulators of RNA homeostasis. We structurally and functionally characterize Mip6, a four-RNA recognition motif (RRM)-containing RBP, as a functional and physical interactor of the export factor Mex67. Mip6-RRM4 directly interacts with the ubiquitin-associated (UBA) domain of Mex67 through a loop containing tryptophan 442. Mip6 shuttles between the nucleus and the cytoplasm in a Mex67-dependent manner and concentrates in cytoplasmic foci under stress. Photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation experiments show preferential binding of Mip6 to mRNAs regulated by the stress-response Msn2/4 transcription factors. Consistent with this binding, MIP6 deletion affects their export and expression levels. Additionally, Mip6 interacts physically and/or functionally with proteins with a role in mRNA metabolism and transcription such as Rrp6, Xrn1, Sgf73, and Rpb1. These results reveal a novel role for Mip6 in the homeostasis of Msn2/4-dependent transcripts through its direct interaction with the Mex67 UBA domain.
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Grants
- BFU2014-57636 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- BFU2015-71978 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- SAF2015-67077-R Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- SAF2017-89901-R Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- CTQ2018-84371 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- PGC2018-099872-B-I00 Ministerio de Ciencia, Innovación y Universidades (Ministry of Science, Innovation and Universities)
- PROM/2012/061 Generalitat Valenciana (Regional Government of Valencia)
- PROMETEO 2016/093 Generalitat Valenciana (Regional Government of Valencia)
- ACOMP2014/061 Generalitat Valenciana (Regional Government of Valencia)
- B2017/BMD-3770 Comunidad de Madrid (Madrid Autonomous Community)
- Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- Comunidad de Madrid (Madrid Autonomous Community)
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Affiliation(s)
- Manuel Martín‐Expósito
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Maria‐Eugenia Gas
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Nada Mohamad
- Signal Transduction LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
| | - Carme Nuño‐Cabanes
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Ana Tejada‐Colón
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
| | - Pau Pascual‐García
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
- Present address:
Department of Cell and Developmental BiologyEpigenetics InstitutePerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Lorena de la Fuente
- Genomics of Gene Expression LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
| | - Belén Chaves‐Arquero
- Department of Biological Physical ChemistryInstitute of Physical‐Chemistry “Rocasolano” (CSIC)MadridSpain
| | - Jonathan Merran
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Jeffry Corden
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Ana Conesa
- Genetics InstituteUniversity of FloridaGainesvilleFLUSA
- Microbiology and Cell Science DepartmentInstitute for Food and Agricultural ResearchUniversity of FloridaGainesvilleFLUSA
| | | | - Jerónimo Bravo
- Signal Transduction LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
| | - Susana Rodríguez‐Navarro
- Gene Expression and RNA Metabolism LaboratoryInstituto de Biomedicina de Valencia (CSIC)ValenciaSpain
- Gene Expression and RNA Metabolism LaboratoryCentro de Investigación Príncipe Felipe (CIPF)ValenciaSpain
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22
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Abstract
Nuclear pore complexes (NPCs), the channels connecting the nucleus with the cytoplasm, are the largest protein structures of the nuclear envelope. In addition to their role in regulating nucleocytoplasmic transport, increasing evidence shows that these multiprotein structures play central roles in the regulation of gene activity. In light of recent discoveries, NPCs are emerging as scaffolds that mediate the regulation of specific gene sets at the nuclear periphery. The function of NPCs as genome organizers and hubs for transcriptional regulation provides additional evidence that the compartmentalization of genes and transcriptional regulators within the nuclear space is an important mechanism of gene expression regulation.
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Affiliation(s)
- Maximiliano A D'Angelo
- a Sanford Burnham Prebys Medical Discovery Institute, Development, Aging and Regeneration Program, NCI-Designated Cancer Center , 10901 N. Torrey Pines Road, La Jolla , CA , United States
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23
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Florini F, Naguleswaran A, Gharib WH, Bringaud F, Roditi I. Unexpected diversity in eukaryotic transcription revealed by the retrotransposon hotspot family of Trypanosoma brucei. Nucleic Acids Res 2019; 47:1725-1739. [PMID: 30544263 PMCID: PMC6393297 DOI: 10.1093/nar/gky1255] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/28/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022] Open
Abstract
The path from DNA to RNA to protein in eukaryotes is guided by a series of factors linking transcription, mRNA export and translation. Many of these are conserved from yeast to humans. Trypanosomatids, which diverged early in the eukaryotic lineage, exhibit unusual features such as polycistronic transcription and trans-splicing of all messenger RNAs. They possess basal transcription factors, but lack recognisable orthologues of many factors required for transcription elongation and mRNA export. We show that retrotransposon hotspot (RHS) proteins fulfil some of these functions and that their depletion globally impairs nascent RNA synthesis by RNA polymerase II. Three sub-families are part of a coordinated process in which RHS6 is most closely associated with chromatin, RHS4 is part of the Pol II complex and RHS2 connects transcription with the translation machinery. In summary, our results show that the components of eukaryotic transcription are far from being universal, and reveal unsuspected plasticity in the course of evolution.
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Affiliation(s)
- Francesca Florini
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School of Cellular and Biomedical Science, University of Bern, Bern, Switzerland
| | | | - Walid H Gharib
- Interfaculty Bioinformatics Unit, University of Bern, Switzerland
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234 CNRS, Université de Bordeaux, France
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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24
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Buchwalter A, Kaneshiro JM, Hetzer MW. Coaching from the sidelines: the nuclear periphery in genome regulation. Nat Rev Genet 2019; 20:39-50. [PMID: 30356165 DOI: 10.1038/s41576-018-0063-5] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The genome is packaged and organized nonrandomly within the 3D space of the nucleus to promote efficient gene expression and to faithfully maintain silencing of heterochromatin. The genome is enclosed within the nucleus by the nuclear envelope membrane, which contains a set of proteins that actively participate in chromatin organization and gene regulation. Technological advances are providing views of genome organization at unprecedented resolution and are beginning to reveal the ways that cells co-opt the structures of the nuclear periphery for nuclear organization and gene regulation. These genome regulatory roles of proteins of the nuclear periphery have important influences on development, disease and ageing.
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Affiliation(s)
- Abigail Buchwalter
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA.,Department of Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Jeanae M Kaneshiro
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Martin W Hetzer
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.
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25
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Abstract
The Three prime repair exonuclease 2 (TREX-2) complex functions as a platform to which many of the components of the nuclear mRNA processing machinery bind, facilitating integration of this phase of the gene expression pathway, as well as mediating the re-positioning of highly regulated actively transcribing genes (such as GAL1) to nuclear pores (NPCs) to accelerate their activation. In Saccharomyces cerevisiae the TREX-2 complex is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31 and two Sus1 chains are bound. A combination of X-ray crystallography and electron microscopy studies have established the structure of two major regions of this complex: the M-region that functions to bind nucleic acids and the CID region that functions to link the complex to nuclear pores. These structures have facilitated the engineering of mutants that have been used to define the contributions made by the TREX-2 complex to locating high-expressed genes to nuclear pores and the contributions made to mRNA nuclear export.
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Affiliation(s)
- Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.
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Evangelista FM, Maglott-Roth A, Stierle M, Brino L, Soutoglou E, Tora L. Transcription and mRNA export machineries SAGA and TREX-2 maintain monoubiquitinated H2B balance required for DNA repair. J Cell Biol 2018; 217:3382-3397. [PMID: 30054449 PMCID: PMC6168256 DOI: 10.1083/jcb.201803074] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/19/2018] [Accepted: 06/28/2018] [Indexed: 11/22/2022] Open
Abstract
The SAGA coactivator complex and the nuclear pore–associated TREX-2 complex couple transcription with mRNA export. Evangelista et al. identify a novel interplay between TREX-2 and the deubiquitination module of SAGA that is necessary to maintain monoubiquitinated H2B levels required for efficient DNA repair through homologous recombination. DNA repair is critical to maintaining genome integrity, and its dysfunction can cause accumulation of unresolved damage that leads to genomic instability. The Spt–Ada–Gcn5 acetyltransferase (SAGA) coactivator complex and the nuclear pore–associated transcription and export complex 2 (TREX-2) couple transcription with mRNA export. In this study, we identify a novel interplay between human TREX-2 and the deubiquitination module (DUBm) of SAGA required for genome stability. We find that the scaffold subunit of TREX-2, GANP, positively regulates DNA repair through homologous recombination (HR). In contrast, DUBm adaptor subunits ENY2 and ATXNL3 are required to limit unscheduled HR. These opposite roles are achieved through monoubiquitinated histone H2B (H2Bub1). Interestingly, the activity of the DUBm of SAGA on H2Bub1 is dependent on the integrity of the TREX-2 complex. Thus, we describe the existence of a functional interaction between human TREX-2 and SAGA DUBm that is key to maintaining the H2B/HB2ub1 balance needed for efficient repair and HR.
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Affiliation(s)
- Federica M Evangelista
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Anne Maglott-Roth
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Matthieu Stierle
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Laurent Brino
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Evi Soutoglou
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France .,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - László Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France .,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
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Mittal C, Culbertson SJ, Shogren-Knaak MA. Distinct requirements of linker DNA and transcriptional activators in promoting SAGA-mediated nucleosome acetylation. J Biol Chem 2018; 293:13736-13749. [PMID: 30054274 DOI: 10.1074/jbc.ra118.004487] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/20/2018] [Indexed: 01/08/2023] Open
Abstract
The Spt-Ada-Gcn5 acetyltransferase (SAGA) family of transcriptional coactivators are prototypical nucleosome acetyltransferase complexes that regulate multiple steps in gene transcription. The size and complexity of both the SAGA enzyme and the chromatin substrate provide numerous opportunities for regulating the acetylation process. To better probe this regulation, here we developed a bead-based nucleosome acetylation assay to characterize the binding interactions and kinetics of acetylation with different nucleosomal substrates and the full SAGA complex purified from budding yeast (Saccharomyces cerevisiae). We found that SAGA-mediated nucleosome acetylation is stimulated up to 9-fold by DNA flanking the nucleosome, both by facilitating the binding of SAGA and by accelerating acetylation turnover. This stimulation required that flanking DNA is present on both sides of the nucleosome and that one side is >15 bp long. The Gal4-VP16 transcriptional activator fusion protein could also augment nucleosome acetylation up to 5-fold. However, contrary to our expectations, this stimulation did not appear to occur by stabilizing the binding of SAGA toward nucleosomes containing an activator-binding site. Instead, increased acetylation turnover by SAGA stimulated nucleosome acetylation. These results suggest that the Gal4-VP16 transcriptional activator directly stimulates acetylation via a dual interaction with both flanking DNA and SAGA. Altogether, these findings uncover several critical mechanisms of SAGA regulation by chromatin substrates.
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Affiliation(s)
- Chitvan Mittal
- From the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - Sannie J Culbertson
- From the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - Michael A Shogren-Knaak
- From the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
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Manhas S, Ma L, Measday V. The yeast Ty1 retrotransposon requires components of the nuclear pore complex for transcription and genomic integration. Nucleic Acids Res 2018; 46:3552-3578. [PMID: 29514267 PMCID: PMC5909446 DOI: 10.1093/nar/gky109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 02/01/2018] [Accepted: 02/26/2018] [Indexed: 01/06/2023] Open
Abstract
Nuclear pore complexes (NPCs) orchestrate cargo between the cytoplasm and nucleus and regulate chromatin organization. NPC proteins, or nucleoporins (Nups), are required for human immunodeficiency virus type 1 (HIV-1) gene expression and genomic integration of viral DNA. We utilize the Ty1 retrotransposon of Saccharomyces cerevisiae (S. cerevisiae) to study retroviral integration because retrotransposons are the progenitors of retroviruses and have conserved integrase (IN) enzymes. Ty1-IN targets Ty1 elements into the genome upstream of RNA polymerase (Pol) III transcribed genes such as transfer RNA (tRNA) genes. Evidence that S. cerevisiae tRNA genes are recruited to NPCs prompted our investigation of a functional role for the NPC in Ty1 targeting into the genome. We find that Ty1 mobility is reduced in multiple Nup mutants that cannot be accounted for by defects in Ty1 gene expression, cDNA production or Ty1-IN nuclear entry. Instead, we find that Ty1 insertion upstream of tRNA genes is impaired. We also identify Nup mutants with wild type Ty1 mobility but impaired Ty1 targeting. The NPC nuclear basket, which interacts with chromatin, is required for both Ty1 expression and nucleosome targeting. Deletion of components of the NPC nuclear basket causes mis-targeting of Ty1 elements to the ends of chromosomes.
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Affiliation(s)
- Savrina Manhas
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Lina Ma
- Wine Research Centre, 2205 East Mall, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Vivien Measday
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- Wine Research Centre, 2205 East Mall, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
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30
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García-Molinero V, García-Martínez J, Reja R, Furió-Tarí P, Antúnez O, Vinayachandran V, Conesa A, Pugh BF, Pérez-Ortín JE, Rodríguez-Navarro S. The SAGA/TREX-2 subunit Sus1 binds widely to transcribed genes and affects mRNA turnover globally. Epigenetics Chromatin 2018; 11:13. [PMID: 29598828 PMCID: PMC5875001 DOI: 10.1186/s13072-018-0184-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/23/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Eukaryotic transcription is regulated through two complexes, the general transcription factor IID (TFIID) and the coactivator Spt-Ada-Gcn5 acetyltransferase (SAGA). Recent findings confirm that both TFIID and SAGA contribute to the synthesis of nearly all transcripts and are recruited genome-wide in yeast. However, how this broad recruitment confers selectivity under specific conditions remains an open question. RESULTS Here we find that the SAGA/TREX-2 subunit Sus1 associates with upstream regulatory regions of many yeast genes and that heat shock drastically changes Sus1 binding. While Sus1 binding to TFIID-dominated genes is not affected by temperature, its recruitment to SAGA-dominated genes and RP genes is significantly disturbed under heat shock, with Sus1 relocated to environmental stress-responsive genes in these conditions. Moreover, in contrast to recent results showing that SAGA deubiquitinating enzyme Ubp8 is dispensable for RNA synthesis, genomic run-on experiments demonstrate that Sus1 contributes to synthesis and stability of a wide range of transcripts. CONCLUSIONS Our study provides support for a model in which SAGA/TREX-2 factor Sus1 acts as a global transcriptional regulator in yeast but has differential activity at yeast genes as a function of their transcription rate or during stress conditions.
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Affiliation(s)
- Varinia García-Molinero
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Eduardo Primo Yúfera 3, 46012, Valencia, Spain.,Inserm Avenir: 'Biology of Repetitive Sequences'-Institute of Human Genetics, CNRS UPR1142, Montpellier, France
| | - José García-Martínez
- Departamento de Genética and E.R.I. Biotecmed, Facultad de Biología, Universitat de València, C/Dr. Moliner 50, 46100, Burjassot, Spain
| | - Rohit Reja
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, The Pennsylvania State University, Pennsylvania, PA, 16802, USA.,Genentech Inc., South San Francisco, CA, USA
| | - Pedro Furió-Tarí
- Genomics of Gene Expression Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Eduardo Primo Yúfera 3, 46012, Valencia, Spain
| | - Oreto Antúnez
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Facultad de Biología, Universitat de València, C/Dr. Moliner 50, 46100, Burjassot, Spain
| | - Vinesh Vinayachandran
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, The Pennsylvania State University, Pennsylvania, PA, 16802, USA
| | - Ana Conesa
- Genomics of Gene Expression Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Eduardo Primo Yúfera 3, 46012, Valencia, Spain.,Microbiology and Cell Science Department, Institute for Food and Agricultural Sciences, University of Florida, P.O. Box 110700, Gainesville, FL, 32611-0700, USA.,Genetics Institute, University of Florida, 2033 Mowry Road, Gainesville, FL, 32610, USA
| | - B Franklin Pugh
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, The Pennsylvania State University, Pennsylvania, PA, 16802, USA
| | - José E Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Facultad de Biología, Universitat de València, C/Dr. Moliner 50, 46100, Burjassot, Spain
| | - Susana Rodríguez-Navarro
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas (CSIC), Jaime Roig 11, 46010, Valencia, Spain. .,Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Eduardo Primo Yúfera 3, 46012, Valencia, Spain.
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Pfab A, Bruckmann A, Nazet J, Merkl R, Grasser KD. The Adaptor Protein ENY2 Is a Component of the Deubiquitination Module of the Arabidopsis SAGA Transcriptional Co-activator Complex but not of the TREX-2 Complex. J Mol Biol 2018; 430:1479-1494. [PMID: 29588169 DOI: 10.1016/j.jmb.2018.03.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/20/2018] [Accepted: 03/20/2018] [Indexed: 12/26/2022]
Abstract
The conserved nuclear protein ENY2 (Sus1 in yeast) is involved in coupling transcription and mRNA export in yeast and metazoa, as it is a component both of the transcriptional co-activator complex SAGA and of the mRNA export complex TREX-2. Arabidopsis thaliana ENY2 is widely expressed in the plant and it localizes to the nucleoplasm, but unlike its yeast/metazoan orthologs, it is not enriched in the nuclear envelope. Affinity purification of ENY2 in combination with mass spectrometry revealed that it co-purified with SAGA components, but not with the nuclear pore-associated TREX-2. In addition, further targeted proteomics analyses by reciprocal tagging established the composition of the Arabidopsis SAGA complex consisting of the four modules HATm, SPTm, TAFm and DUBm, and that several SAGA subunits occur in alternative variants. While the HATm, SPTm and TAFm robustly co-purified with each other, the deubiquitination module (DUBm) appears to associate with the other SAGA modules more weakly/dynamically. Consistent with a homology model of the Arabidopsis DUBm, the SGF11 protein interacts directly with ENY2 and UBP22. Plants depleted in the DUBm components, SGF11 or ENY2, are phenotypically only mildly affected, but they contain increased levels of ubiquitinated histone H2B, indicating that the SAGA-DUBm has histone deubiquitination activity in plants. In addition to transcription-related proteins (i.e., transcript elongation factors, Mediator), many splicing factors were found to associate with SAGA, linking the SAGA complex and ongoing transcription with mRNA processing.
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Affiliation(s)
- Alexander Pfab
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Astrid Bruckmann
- Department for Biochemistry I, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Julian Nazet
- Department for Biochemistry II, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Rainer Merkl
- Department for Biochemistry II, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Klaus D Grasser
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany.
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32
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Ávila AR, Cabezas-Cruz A, Gissot M. mRNA export in the apicomplexan parasite Toxoplasma gondii: emerging divergent components of a crucial pathway. Parasit Vectors 2018; 11:62. [PMID: 29370868 PMCID: PMC5785795 DOI: 10.1186/s13071-018-2648-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/15/2018] [Indexed: 01/08/2023] Open
Abstract
Control of gene expression is crucial for parasite survival and is the result of a series of processes that are regulated to permit fine-tuning of gene expression in response to biological changes during the life-cycle of apicomplexan parasites. Control of mRNA nuclear export is a key process in eukaryotic cells but is poorly understood in apicomplexan parasites. Here, we review recent knowledge regarding this process with an emphasis on T. gondii. We describe the presence of divergent orthologs and discuss structural and functional differences in export factors between apicomplexans and other eukaryotic lineages. Undoubtedly, the use of the CRISPR/Cas9 system in high throughput screenings associated with the discovery of mRNA nuclear export complexes by proteomic analysis will contribute to identify these divergent factors. Ligand-based or structure-based strategies may be applied to investigate the potential use of these proteins as targets for new antiprotozoal agents.
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Affiliation(s)
- Andréa Rodrigues Ávila
- Instituto Carlos Chagas, FIOCRUZ, Rua Algacyr Munhoz Mader, 3775. CIC, Curitiba, PR, 81350-010, Brazil. .,UMR BIPAR, Animal Health Laboratory, ANSES, INRA, ENVA, Maisons Alfort, Cedex, France.
| | - Alexjandro Cabezas-Cruz
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, ENVA, Maisons Alfort, Cedex, France.,Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Mathieu Gissot
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Centre d'Infection et d'Immunité de Lille, F-59000, Lille, France.
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Gordon JMB, Aibara S, Stewart M. Structure of the Sac3 RNA-binding M-region in the Saccharomyces cerevisiae TREX-2 complex. Nucleic Acids Res 2017; 45:5577-5585. [PMID: 28334829 PMCID: PMC5435946 DOI: 10.1093/nar/gkx158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 03/01/2017] [Indexed: 01/29/2023] Open
Abstract
Transcription-export complex 2 (TREX-2, or THSC) facilitates localization of actively transcribing genes such as GAL1 to the nuclear periphery, contributes to the generation of export-competent mRNPs and influences gene expression through interactions with Mediator. TREX-2 is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31 and Sus1 bind and consists of three modules: the N-region (Sac3∼1-100), which binds mRNA export factor Mex67:Mtr2; the M-region, in which Thp1 and Sem1 bind to Sac3∼100-550; and the CID region in which Cdc31 and two Sus1 chains bind to Sac3∼720-805. Although the M-region of Sac3 was originally thought to encompass residues ∼250-550, we report here the 2.3Å resolution crystal structure of a complex containing Sac3 residues 60–550 that indicates that the TPR-like repeats of the M-region extend to residue 137 and that residues 90–125 form a novel loop that links Sac3 to Thp1. These new structural elements are important for growth and mRNA export in vivo. Although deleting Sac3 residues 1–90 produced a wild-type phenotype, deletion of the loop as well generated growth defects at 37°C, whereas the deletion of residues 1–250 impaired mRNA export and also generated longer lag times when glucose or raffinose was replaced by galactose as the carbon source.
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Affiliation(s)
- James M B Gordon
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Shintaro Aibara
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
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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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Labade AS, Karmodiya K, Sengupta K. HOXA repression is mediated by nucleoporin Nup93 assisted by its interactors Nup188 and Nup205. Epigenetics Chromatin 2016; 9:54. [PMID: 27980680 PMCID: PMC5135769 DOI: 10.1186/s13072-016-0106-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 11/23/2016] [Indexed: 12/22/2022] Open
Abstract
Background The nuclear pore complex (NPC) mediates nuclear transport of RNA and proteins into and out of the nucleus. Certain nucleoporins have additional functions in chromatin organization and transcription regulation. Nup93 is a scaffold nucleoporin at the nuclear pore complex which is associated with human chromosomes 5, 7 and 16 and with the promoters of the HOXA gene as revealed by ChIP-on-chip studies using tiling microarrays for these chromosomes. However, the functional consequences of the association of Nup93 with HOXA is unknown. Results Here, we examined the association of Nup93 with the HOXA gene cluster and its consequences on HOXA gene expression in diploid colorectal cancer cells (DLD1). Nup93 showed a specific enrichment ~1 Kb upstream of the transcription start site of each of the HOXA1, HOXA3 and HOXA5 promoters, respectively. Furthermore, the association of Nup93 with HOXA was assisted by its interacting partners Nup188 and Nup205. The depletion of the Nup93 sub-complex significantly upregulated HOXA gene expression levels. However, expression levels of a control gene locus (GLCCI1) on human chromosome 7 were unaffected. Three-dimensional fluorescence in situ hybridization (3D-FISH) analyses revealed that the depletion of the Nup93 sub-complex (but not Nup98) disengages the HOXA gene locus from the nuclear periphery, suggesting a potential role for Nup93 in tethering and repressing the HOXA gene cluster. Consistently, Nup93 knockdown increased active histone marks (H3K9ac), decreased repressive histone marks (H3K27me3) on the HOXA1 promoter and increased transcription elongation marks (H3K36me3) within the HOXA1 gene. Moreover, the combined depletion of Nup93 and CTCF (a known organizer of HOXA gene cluster) but not Nup93 alone, significantly increased GLCCI1 gene expression levels. Taken together, this suggests a novel role for Nup93 and its interactors in repressing the HOXA gene cluster. Conclusions This study reveals that the nucleoporin Nup93 assisted by its interactors Nup188 and Nup205 mediates the repression of HOXA gene expression. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0106-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ajay S Labade
- Biology, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008 India
| | - Krishanpal Karmodiya
- Biology, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008 India
| | - Kundan Sengupta
- Biology, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008 India
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Hot1 factor recruits co-activator Sub1 and elongation complex Spt4/5 to osmostress genes. Biochem J 2016; 473:3065-79. [DOI: 10.1042/bcj20160463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/01/2016] [Indexed: 11/17/2022]
Abstract
Hyperosmotic stress response involves the adaptative mechanisms needed for cell survival. Under high osmolarity conditions, many stress response genes are activated by several unrelated transcription factors that are controlled by the Hog1 kinase. Osmostress transcription factor Hot1 regulates the expression of several genes involved in glycerol biosynthesis, and the presence of this transcription factor in their promoters is essential for RNApol II recruitment. The physical association between Hog1 and Hot1 activates this transcription factor and directs the RNA polymerase II localization at these promoters. We, herein, demonstrate that physical and genetic interactions exist between Hot1 and several proteins involved in transcriptional and posttranscriptional processes: for example, transcription co-activator Sub1 and elongation complex Spt4/5. The results presented in this work demonstrate that Hot1 enrichment is not detected through the coding regions of its target genes and rule out a direct role in transcription elongation. Instead, other data presented herein indicate a key function of the Hot1 transcription factor in the recruitment of these proteins to the promoter or the 5′-coding region of the genes under its control.
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The Sac3 TPR-like region in the Saccharomyces cerevisiae TREX-2 complex is more extensive but independent of the CID region. J Struct Biol 2016; 195:316-324. [PMID: 27422657 PMCID: PMC4991852 DOI: 10.1016/j.jsb.2016.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/08/2016] [Accepted: 07/11/2016] [Indexed: 11/21/2022]
Abstract
Transcription-export complex 2 (TREX-2 complex) facilitates the localization of actively transcribing genes to the nuclear periphery and also functions to contribute to the generation of export-competent mRNPs through interactions with the general mRNA nuclear export factor Mex67:Mtr2. The TREX-2 complex is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31, and Sus1 bind. TREX-2 can be subdivided into two modules: one, in which Thp1 and Sem1 bind to the Sac3M region (residues ∼100–551), and the other in which Cdc31 and two Sus1 chains bind to the Sac3CID region (residues ∼710–805). Complementary structural analyses using X-ray crystallography, electron microscopy, and small-angle X-ray scattering of the Saccharomyces cerevisiae TREX-2 complex, expressed using Baculovirus-infected Sf9 cells, have indicated that the TPR-like repeats of the Sac3M region extend considerably further towards the N-terminus than previously thought, and also indicate that this region and Sac3CID:Sus1:Cdc31 region of the S. cerevisiae complex are structurally independent. Although the density visible accounted for only ∼100 kDa, a 5.3 Å resolution cryo-EM reconstruction was obtained of the M-region of TREX-2 that showed an additional three putative α-helices extending towards the Sac3 N-terminus and these helices were also seen in a 4.9 Å resolution structure obtained by X-ray crystallography. Summary statement We describe the expression, purification and structural characterization of the S. cerevisiae TREX-2 complex and demonstrate that the Sac3 TPR-like repeats are more extensive than previously thought and that the M- and CID-regions do not appear to have a defined spatial orientation.
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Hale CJ, Potok ME, Lopez J, Do T, Liu A, Gallego-Bartolome J, Michaels SD, Jacobsen SE. Identification of Multiple Proteins Coupling Transcriptional Gene Silencing to Genome Stability in Arabidopsis thaliana. PLoS Genet 2016; 12:e1006092. [PMID: 27253878 PMCID: PMC4890748 DOI: 10.1371/journal.pgen.1006092] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/10/2016] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic genomes are regulated by epigenetic marks that act to modulate transcriptional control as well as to regulate DNA replication and repair. In Arabidopsis thaliana, mutation of the ATXR5 and ATXR6 histone methyltransferases causes reduction in histone H3 lysine 27 monomethylation, transcriptional upregulation of transposons, and a genome instability defect in which there is an accumulation of excess DNA corresponding to pericentromeric heterochromatin. We designed a forward genetic screen to identify suppressors of the atxr5/6 phenotype that uncovered loss-of-function mutations in two components of the TREX-2 complex (AtTHP1, AtSAC3B), a SUMO-interacting E3 ubiquitin ligase (AtSTUbL2) and a methyl-binding domain protein (AtMBD9). Additionally, using a reverse genetic approach, we show that a mutation in a plant homolog of the tumor suppressor gene BRCA1 enhances the atxr5/6 phenotype. Through characterization of these mutations, our results suggest models for the production atxr5 atxr6-induced extra DNA involving conflicts between the replicative and transcriptional processes in the cell, and suggest that the atxr5 atxr6 transcriptional defects may be the cause of the genome instability defects in the mutants. These findings highlight the critical intersection of transcriptional silencing and DNA replication in the maintenance of genome stability of heterochromatin. In eukaryotic genomes cellular processes such as transcription and replication need to be tightly controlled in order to promote genomic stability and prevent deleterious mutations. In Arabidopsis thaliana, two redundant histone methyltransferases, ATXR5 and ATXR6, are responsible for the deposition of a silencing epigenetic mark, histone H3 lysine 27 monomethylation. Loss of ATXR5/6 results in transcriptional activation of transposable elements (TEs), upregulation of DNA damage response genes and a genomic instability defect characterized as an excess of DNA corresponding to heterochromatin regions. Using a genetic screen, we sought to find suppressors of the atxr5/6 phenotype, and interestingly, we identified multiple genes implicated in general transcriptional activity. Through genomic characterization of the mutants our data suggest a model where transcriptional silencing of heterochromatin during S-phase is required for proper replication and maintenance of genome stability. These findings emphasize the important relationship between chromatin, transcriptional control and replication in the maintenance of genome stability in a eukaryotic system and identify new players involved in these processes.
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Affiliation(s)
- Christopher J. Hale
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
- Center for Precision Diagnostics, University of Washington, Seattle, Washington, United States of America
| | - Magdalena E. Potok
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Jennifer Lopez
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Truman Do
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Ao Liu
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Javier Gallego-Bartolome
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Scott D. Michaels
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Steven E. Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
- Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Kopytova D, Popova V, Kurshakova M, Shidlovskii Y, Nabirochkina E, Brechalov A, Georgiev G, Georgieva S. ORC interacts with THSC/TREX-2 and its subunits promote Nxf1 association with mRNP and mRNA export in Drosophila. Nucleic Acids Res 2016; 44:4920-33. [PMID: 27016737 PMCID: PMC4889942 DOI: 10.1093/nar/gkw192] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 03/11/2016] [Indexed: 12/20/2022] Open
Abstract
The origin recognition complex (ORC) of eukaryotes associates with the replication origins and initiates the pre-replication complex assembly. In the literature, there are several reports of interaction of ORC with different RNAs. Here, we demonstrate for the first time a direct interaction of ORC with the THSC/TREX-2 mRNA nuclear export complex. The THSC/TREX-2 was purified from the Drosophila embryonic extract and found to bind with a fraction of the ORC. This interaction occurred via several subunits and was essential for Drosophila viability. Also, ORC was associated with mRNP, which was facilitated by TREX-2. ORC subunits interacted with the Nxf1 receptor mediating the bulk mRNA export. The knockdown of Orc5 led to a drop in the Nxf1 association with mRNP, while Orc3 knockdown increased the level of mRNP-bound Nxf1. The knockdown of Orc5, Orc3 and several other ORC subunits led to an accumulation of mRNA in the nucleus, suggesting that ORC participates in the regulation of the mRNP export.
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Affiliation(s)
- Daria Kopytova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Varvara Popova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Maria Kurshakova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Yulii Shidlovskii
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Elena Nabirochkina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Alexander Brechalov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Georgii Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Sofia Georgieva
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
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Stankovic N, Schloesser M, Joris M, Sauvage E, Hanikenne M, Motte P. Dynamic Distribution and Interaction of the Arabidopsis SRSF1 Subfamily Splicing Factors. PLANT PHYSIOLOGY 2016; 170:1000-13. [PMID: 26697894 PMCID: PMC4734559 DOI: 10.1104/pp.15.01338] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/19/2015] [Indexed: 05/19/2023]
Abstract
Ser/Arg-rich (SR) proteins are essential nucleus-localized splicing factors. Our prior studies showed that Arabidopsis (Arabidopsis thaliana) RSZ22, a homolog of the human SRSF7 SR factor, exits the nucleus through two pathways, either dependent or independent on the XPO1 receptor. Here, we examined the expression profiles and shuttling dynamics of the Arabidopsis SRSF1 subfamily (SR30, SR34, SR34a, and SR34b) under control of their endogenous promoter in Arabidopsis and in transient expression assay. Due to its rapid nucleocytoplasmic shuttling and high expression level in transient assay, we analyzed the multiple determinants that regulate the localization and shuttling dynamics of SR34. By site-directed mutagenesis of SR34 RNA-binding sequences and Arg/Ser-rich (RS) domain, we further show that functional RRM1 or RRM2 are dispensable for the exclusive protein nuclear localization and speckle-like distribution. However, mutations of both RRMs induced aggregation of the protein whereas mutation in the RS domain decreased the stability of the protein and suppressed its nuclear accumulation. Furthermore, the RNA-binding motif mutants are defective for their export through the XPO1 (CRM1/Exportin-1) receptor pathway, but retain nucleocytoplasmic mobility. We performed a yeast two hybrid screen with SR34 as bait and discovered SR45 as a new interactor. SR45 is an unusual SR splicing factor bearing two RS domains. These interactions were confirmed in planta by FLIM-FRET and BiFC and the roles of SR34 domains in protein-protein interactions were further studied. Altogether, our report extends our understanding of shuttling dynamics of Arabidopsis SR splicing factors.
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Affiliation(s)
- Nancy Stankovic
- Laboratory of Functional Genomics and Plant Molecular Imaging (N.S., M.S., M.J., M.H., P.M.), Laboratory of Macromolecular Crystallography (E.S.), PhytoSYSTEMS (M.H., P.M.), Centre for Protein Engineering (CIP; N.S., M.S., M.J., E.S., M.H., P.M.), Department of Life Sciences, and Centre for Assistance in Technology of Microscopy (CATM; P.M.), University of Liège, B-4000 Liège, Belgium
| | - Marie Schloesser
- Laboratory of Functional Genomics and Plant Molecular Imaging (N.S., M.S., M.J., M.H., P.M.), Laboratory of Macromolecular Crystallography (E.S.), PhytoSYSTEMS (M.H., P.M.), Centre for Protein Engineering (CIP; N.S., M.S., M.J., E.S., M.H., P.M.), Department of Life Sciences, and Centre for Assistance in Technology of Microscopy (CATM; P.M.), University of Liège, B-4000 Liège, Belgium
| | - Marine Joris
- Laboratory of Functional Genomics and Plant Molecular Imaging (N.S., M.S., M.J., M.H., P.M.), Laboratory of Macromolecular Crystallography (E.S.), PhytoSYSTEMS (M.H., P.M.), Centre for Protein Engineering (CIP; N.S., M.S., M.J., E.S., M.H., P.M.), Department of Life Sciences, and Centre for Assistance in Technology of Microscopy (CATM; P.M.), University of Liège, B-4000 Liège, Belgium
| | - Eric Sauvage
- Laboratory of Functional Genomics and Plant Molecular Imaging (N.S., M.S., M.J., M.H., P.M.), Laboratory of Macromolecular Crystallography (E.S.), PhytoSYSTEMS (M.H., P.M.), Centre for Protein Engineering (CIP; N.S., M.S., M.J., E.S., M.H., P.M.), Department of Life Sciences, and Centre for Assistance in Technology of Microscopy (CATM; P.M.), University of Liège, B-4000 Liège, Belgium
| | - Marc Hanikenne
- Laboratory of Functional Genomics and Plant Molecular Imaging (N.S., M.S., M.J., M.H., P.M.), Laboratory of Macromolecular Crystallography (E.S.), PhytoSYSTEMS (M.H., P.M.), Centre for Protein Engineering (CIP; N.S., M.S., M.J., E.S., M.H., P.M.), Department of Life Sciences, and Centre for Assistance in Technology of Microscopy (CATM; P.M.), University of Liège, B-4000 Liège, Belgium
| | - Patrick Motte
- Laboratory of Functional Genomics and Plant Molecular Imaging (N.S., M.S., M.J., M.H., P.M.), Laboratory of Macromolecular Crystallography (E.S.), PhytoSYSTEMS (M.H., P.M.), Centre for Protein Engineering (CIP; N.S., M.S., M.J., E.S., M.H., P.M.), Department of Life Sciences, and Centre for Assistance in Technology of Microscopy (CATM; P.M.), University of Liège, B-4000 Liège, Belgium
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AbuQattam A, Gallego J, Rodríguez-Navarro S. An intronic RNA structure modulates expression of the mRNA biogenesis factor Sus1. RNA (NEW YORK, N.Y.) 2016; 22:75-86. [PMID: 26546116 PMCID: PMC4691836 DOI: 10.1261/rna.054049.115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/03/2015] [Indexed: 06/05/2023]
Abstract
Sus1 is a conserved protein involved in chromatin remodeling and mRNA biogenesis. Unlike most yeast genes, the SUS1 pre-mRNA of Saccharomyces cerevisiae contains two introns and is alternatively spliced, retaining one or both introns in response to changes in environmental conditions. SUS1 splicing may allow the cell to control Sus1 expression, but the mechanisms that regulate this process remain unknown. Using in silico analyses together with NMR spectroscopy, gel electrophoresis, and UV thermal denaturation experiments, we show that the downstream intron (I2) of SUS1 forms a weakly stable, 37-nucleotide stem-loop structure containing the branch site near its apical loop and the 3' splice site after the stem terminus. A cellular assay revealed that two of four mutants containing altered I2 structures had significantly impaired SUS1 expression. Semiquantitative RT-PCR experiments indicated that all mutants accumulated unspliced SUS1 pre-mRNA and/or induced distorted levels of fully spliced mRNA relative to wild type. Concomitantly, Sus1 cellular functions in histone H2B deubiquitination and mRNA export were affected in I2 hairpin mutants that inhibited splicing. This work demonstrates that I2 structure is relevant for SUS1 expression, and that this effect is likely exerted through modulation of splicing.
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Affiliation(s)
- Ali AbuQattam
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe, Valencia 46012, Spain Facultad de Medicina, Universidad Católica de Valencia, Valencia 46001, Spain
| | - José Gallego
- Facultad de Medicina, Universidad Católica de Valencia, Valencia 46001, Spain
| | - Susana Rodríguez-Navarro
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe, Valencia 46012, Spain
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Sgf73, a subunit of SAGA complex, is required for the assembly of RITS complex in fission yeast. Sci Rep 2015; 5:14707. [PMID: 26443059 PMCID: PMC4595766 DOI: 10.1038/srep14707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/07/2015] [Indexed: 02/04/2023] Open
Abstract
RNA interference (RNAi) is a widespread gene-silencing mechanism and is required for heterochromatin assembly in a variety of organisms. The RNA-induced transcriptional silencing complex (RITS), composed of Ago1, Tas3 and Chp1, is a key component of RNAi machinery in fission yeast that connects short interference RNA (siRNA) and heterochromatin formation. However, the process by which RITS is assembled is not well understood. Here, we identified Sgf73, a subunit of the SAGA co-transcriptional complex, is required for pericentromeric heterochromatin silencing and the generation of siRNA. This novel role of Sgf73 is independent of enzymatic activities or structural integrity of SAGA. Instead, Sgf73 is physically associated with Ago1 and Chp1. The interactions among the subunits of the RITS, including those between Tas3 and Chp1, between Chp1 and Ago1, between Ago1 and Tas3, were all impaired by the deletion of sgf73+. Consistently, the recruitment of Ago1 and Chp1 to the pericentromeric region was abolished in sgf73Δ cells. Our study unveils a moonlighting function of a SAGA subunit. It suggests Sgf73 is a novel factor that promotes assembly of RITS and RNAi-mediated heterochromatin formation.
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Mattout A, Cabianca DS, Gasser SM. Chromatin states and nuclear organization in development--a view from the nuclear lamina. Genome Biol 2015; 16:174. [PMID: 26303512 PMCID: PMC4549078 DOI: 10.1186/s13059-015-0747-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The spatial distribution of chromatin domains in interphase nuclei changes dramatically during development in multicellular organisms. A crucial question is whether nuclear organization is a cause or a result of differentiation. Genetic perturbation of lamina–heterochromatin interactions is helping to reveal the cross-talk between chromatin states and nuclear organization.
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Affiliation(s)
- Anna Mattout
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058, Basel, Switzerland.
| | - Daphne S Cabianca
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058, Basel, Switzerland.
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058, Basel, Switzerland. .,University of Basel, Faculty of Natural Sciences, Klingelbergstrasse 50, CH-4056, Basel, Switzerland.
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Spt-Ada-Gcn5-Acetyltransferase (SAGA) Complex in Plants: Genome Wide Identification, Evolutionary Conservation and Functional Determination. PLoS One 2015; 10:e0134709. [PMID: 26263547 PMCID: PMC4532415 DOI: 10.1371/journal.pone.0134709] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 07/13/2015] [Indexed: 01/17/2023] Open
Abstract
The recruitment of RNA polymerase II on a promoter is assisted by the assembly of basal transcriptional machinery in eukaryotes. The Spt-Ada-Gcn5-Acetyltransferase (SAGA) complex plays an important role in transcription regulation in eukaryotes. However, even in the advent of genome sequencing of various plants, SAGA complex has been poorly defined for their components and roles in plant development and physiological functions. Computational analysis of Arabidopsis thaliana and Oryza sativa genomes for SAGA complex resulted in the identification of 17 to 18 potential candidates for SAGA subunits. We have further classified the SAGA complex based on the conserved domains. Phylogenetic analysis revealed that the SAGA complex proteins are evolutionary conserved between plants, yeast and mammals. Functional annotation showed that they participate not only in chromatin remodeling and gene regulation, but also in different biological processes, which could be indirect and possibly mediated via the regulation of gene expression. The in silico expression analysis of the SAGA components in Arabidopsis and O. sativa clearly indicates that its components have a distinct expression profile at different developmental stages. The co-expression analysis of the SAGA components suggests that many of these subunits co-express at different developmental stages, during hormonal interaction and in response to stress conditions. Quantitative real-time PCR analysis of SAGA component genes further confirmed their expression in different plant tissues and stresses. The expression of representative salt, heat and light inducible genes were affected in mutant lines of SAGA subunits in Arabidopsis. Altogether, the present study reveals expedient evidences of involvement of the SAGA complex in plant gene regulation and stress responses.
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Abstract
Nuclear pore complexes (NPCs) are composed of several copies of ∼30 different proteins called nucleoporins (Nups). NPCs penetrate the nuclear envelope (NE) and regulate the nucleocytoplasmic trafficking of macromolecules. Beyond this vital role, NPC components influence genome functions in a transport-independent manner. Nups play an evolutionarily conserved role in gene expression regulation that, in metazoans, extends into the nuclear interior. Additionally, in proliferative cells, Nups play a crucial role in genome integrity maintenance and mitotic progression. Here we discuss genome-related functions of Nups and their impact on essential DNA metabolism processes such as transcription, chromosome duplication, and segregation.
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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: 66] [Impact Index Per Article: 7.3] [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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47
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RNA Export through the NPC in Eukaryotes. Genes (Basel) 2015; 6:124-49. [PMID: 25802992 PMCID: PMC4377836 DOI: 10.3390/genes6010124] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/27/2015] [Accepted: 03/10/2015] [Indexed: 02/08/2023] Open
Abstract
In eukaryotic cells, RNAs are transcribed in the nucleus and exported to the cytoplasm through the nuclear pore complex. The RNA molecules that are exported from the nucleus into the cytoplasm include messenger RNAs (mRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), small nuclear RNAs (snRNAs), micro RNAs (miRNAs), and viral mRNAs. Each RNA is transported by a specific nuclear export receptor. It is believed that most of the mRNAs are exported by Nxf1 (Mex67 in yeast), whereas rRNAs, snRNAs, and a certain subset of mRNAs are exported in a Crm1/Xpo1-dependent manner. tRNAs and miRNAs are exported by Xpot and Xpo5. However, multiple export receptors are involved in the export of some RNAs, such as 60S ribosomal subunit. In addition to these export receptors, some adapter proteins are required to export RNAs. The RNA export system of eukaryotic cells is also used by several types of RNA virus that depend on the machineries of the host cell in the nucleus for replication of their genome, therefore this review describes the RNA export system of two representative viruses. We also discuss the NPC anchoring-dependent mRNA export factors that directly recruit specific genes to the NPC.
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Sumoylation is Required for the Cytoplasmic Accumulation of a Subset of mRNAs. Genes (Basel) 2014; 5:982-1000. [PMID: 25333844 PMCID: PMC4276922 DOI: 10.3390/genes5040982] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/26/2014] [Accepted: 10/04/2014] [Indexed: 12/17/2022] Open
Abstract
In order to discover novel proteins that promote the nuclear export of newly synthesized mRNAs in mammalian cells, we carried out a limited RNAi screen for proteins required for the proper cytoplasmic distribution of a model intronless mRNA. From this screen we obtained two hits, Ubc9 (SUMO-conjugating E2 enzyme) and GANP (germinal center-associated nuclear protein). Depletion of Ubc9 inhibited the proper cytoplasmic distribution of certain overexpressed intronless mRNAs, while depletion of GANP affected all tested mRNAs. Depletion of Sae1, which is also required for sumoylation, partially inhibited the cytoplasmic distribution of our model mRNA. Interestingly, the block in cytoplasmic accumulation in Ubc9-depleted cells could be overcome if an intron was incorporated into the mRNA. Surprisingly, Ubc9-depleted cells had normal nuclear export of newly synthesized intronless mRNAs, indicating that the observed accumulation of the model mRNA in the nuclei of transfected cells was likely due to some more general perturbation. Indeed, depletion of Ubc9, coupled with the overexpression of the intronless mRNAs, caused the redistribution of the nuclear speckle protein SC35 to cytoplasmic foci. Our results suggest that sumoylation may play a role in the proper assembly of mRNPs and/or the distribution of key RNA binding proteins, and may thus contribute to general protein expression patterns.
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49
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Sumoylation and transcription regulation at nuclear pores. Chromosoma 2014; 124:45-56. [PMID: 25171917 PMCID: PMC4339684 DOI: 10.1007/s00412-014-0481-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 01/22/2023]
Abstract
Increasing evidence indicates that besides promoters, enhancers, and epigenetic modifications, nuclear organization is another parameter contributing to optimal control of gene expression. Although differences between species exist, the influence of gene positioning on expression seems to be a conserved feature from yeast to Drosophila and mammals. The nuclear periphery is one of the nuclear compartments implicated in gene regulation. It consists of the nuclear envelope (NE) and the nuclear pore complexes (NPC), which have distinct roles in the control of gene expression. The NPC has recently been shown to tether proteins involved in the sumoylation pathway. Here, we will focus on the importance of gene positioning and NPC-linked sumoylation/desumoylation in transcription regulation. We will mainly discuss observations made in the yeast Saccharomyces cerevisiae model system and highlight potential parallels in metazoan species.
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50
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Durairaj G, Sen R, Uprety B, Shukla A, Bhaumik SR. Sus1p facilitates pre-initiation complex formation at the SAGA-regulated genes independently of histone H2B de-ubiquitylation. J Mol Biol 2014; 426:2928-2941. [PMID: 24911582 DOI: 10.1016/j.jmb.2014.05.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/29/2014] [Accepted: 05/31/2014] [Indexed: 12/23/2022]
Abstract
Sus1p is a common component of transcriptional co-activator, SAGA (Spt-Ada-Gcn5-Acetyltransferase), and mRNA export complex, TREX-2 (Transcription-export 2), and is involved in promoting transcription and mRNA export. However, it is not clearly understood how Sus1p promotes transcription. Here, we show that Sus1p is predominantly recruited to the upstream activating sequence of a SAGA-dependent gene, GAL1, under transcriptionally active conditions as a component of SAGA to promote the formation of pre-initiation complex (PIC) at the core promoter and, consequently, transcriptional initiation. Likewise, Sus1p promotes the PIC formation at other SAGA-dependent genes and hence transcriptional initiation. Such function of Sus1p in promoting PIC formation and transcriptional initiation is not mediated via its role in regulation of SAGA's histone H2B de-ubiquitylation activity. However, Sus1p's function in regulation of histone H2B ubiquitylation is associated with transcriptional elongation, DNA repair and replication. Collectively, our results support that Sus1p promotes PIC formation (and hence transcriptional initiation) at the SAGA-regulated genes independently of histone H2B de-ubiquitylation and further controls transcriptional elongation, DNA repair and replication via orchestration of histone H2B ubiquitylation, thus providing distinct functional insights of Sus1p in regulation of DNA transacting processes.
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Affiliation(s)
- Geetha Durairaj
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Rwik Sen
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Bhawana Uprety
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Abhijit Shukla
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
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