1
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Banerjee S, Nagasawa CK, Widen SG, Garcia-Blanco MA. Parsing the roles of DExD-box proteins DDX39A and DDX39B in alternative RNA splicing. Nucleic Acids Res 2024:gkae431. [PMID: 38801080 DOI: 10.1093/nar/gkae431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 05/01/2024] [Accepted: 05/12/2024] [Indexed: 05/29/2024] Open
Abstract
DExD-box RNA proteins DDX39A and DDX39B are highly homologous paralogs that are conserved in vertebrates. They are required for energy-driven reactions involved in RNA processing. Although we have some understanding of how their functions overlap in RNA nuclear export, our knowledge of whether or not these proteins have specific or redundant functions in RNA splicing is limited. Our previous work has shown that DDX39B is responsible for regulating the splicing of important immune transcripts IL7R and FOXP3. In this study, we aimed to investigate whether DDX39A, a highly homologous paralog of DDX39B, plays a similar role in regulating alternative RNA splicing. We find that DDX39A and DDX39B have significant redundancy in their gene targets, but there are targets that uniquely require one or the other paralog. For instance, DDX39A is incapable of complementing defective splicing of IL7R exon 6 when DDX39B is depleted. This exon and other cassette exons that specifically depend on DDX39B have U-poor/C-rich polypyrimidine tracts in the upstream intron and this variant polypyrimidine tract is required for DDX39B dependency. This study provides evidence that despite a high degree of functional redundancy, DDX39A and DDX39B are selectively required for the splicing of specific pre-mRNAs.
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Affiliation(s)
- Shefali Banerjee
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903, USA
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550, USA
| | - Chloe K Nagasawa
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903, USA
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550, USA
- Human Pathophysiology and Translational Medicine Program, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
| | - Steven G Widen
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550, USA
| | - Mariano A Garcia-Blanco
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903, USA
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550, USA
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2
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Yellamaty R, Sharma S. Critical Cellular Functions and Mechanisms of Action of the RNA Helicase UAP56. J Mol Biol 2024; 436:168604. [PMID: 38729260 DOI: 10.1016/j.jmb.2024.168604] [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: 03/06/2024] [Revised: 04/24/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024]
Abstract
Posttranscriptional maturation and export from the nucleus to the cytoplasm are essential steps in the normal processing of many cellular RNAs. The RNA helicase UAP56 (U2AF associated protein 56; also known as DDX39B) has emerged as a critical player in facilitating and co-transcriptionally linking these steps. Originally identified as a helicase involved in pre-mRNA splicing, UAP56 has been shown to facilitate formation of the A complex during spliceosome assembly. Additionally, it has been found to be critical for interactions between components of the exon junction and transcription and export complexes to promote the loading of export receptors. Although it appears to be structurally similar to other helicase superfamily 2 members, UAP56's ability to interact with multiple different protein partners allows it to perform its various cellular functions. Herein, we describe the structure-activity relationship studies that identified protein interactions of UAP56 and its human paralog URH49 (UAP56-related helicase 49; also known as DDX39A) and are beginning to reveal molecular mechanisms by which interacting proteins and substrate RNAs may regulate these helicases. We also provide an overview of reports that have demonstrated less well-characterized roles for UAP56, including R-loop resolution and telomere maintenance. Finally, we discuss studies that indicate a potential pathogenic effect of UAP56 in the development of autoimmune diseases and cancer, and identify the association of somatic and genetic mutations in UAP56 with neurodevelopmental disorders.
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Affiliation(s)
- Ryan Yellamaty
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Shalini Sharma
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA.
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3
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Fujita KI, Yamazaki T, Mayeda A, Masuda S. Terminal regions of UAP56 and URH49 are required for their distinct complex formation functioning to an essential role in mRNA processing and export. Biochem Biophys Res Commun 2024; 703:149682. [PMID: 38377942 DOI: 10.1016/j.bbrc.2024.149682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 02/22/2024]
Abstract
UAP56 and URH49 are closely related RNA helicases that function in selective mRNA processing and export pathways to fine-tune gene expression through distinct complex formations. The complex formation of UAP56 and URH49 is believed to play a crucial role in regulating target mRNAs. However, the mechanisms underlying this complex formation have not been fully elucidated. Here we identified the regions essential for the complex formation of both helicases. The terminal regions of UAP56 and the C-terminal region of URH49 were indispensable for their respective complex formation. Further analysis revealed that a specific amino acid at the C-terminus of UAP56 is critical for its complex formation. Alanine substitution of this amino acid impairs its complex formation and subsequently affected its mRNA processing and export activity. Our study provides a deeper understanding of the basis for the complex formation between UAP56 and URH49.
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Affiliation(s)
- Ken-Ichi Fujita
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan; Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan; Division of Cancer Stem Cell, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan
| | - Tomohiro Yamazaki
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Seiji Masuda
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan; Department of Food Science and Nutrition, Faculty of Agriculture Kindai University, Nara, Nara, 631-8505, Japan; Department of Applied Biological Chemistry, Graduate School of Agriculture, Kindai University, Nara, Nara, Japan; Agricultural Technology and Innovation Research Institute, Kindai University, Nara, Nara, 631-8505, Japan; Antiaging Center, Kindai University, Higashiosaka, Osaka, 577-8502, Japan.
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4
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Marijan D, Momchilova EA, Burns D, Chandhok S, Zapf R, Wille H, Potoyan DA, Audas TE. Protein thermal sensing regulates physiological amyloid aggregation. Nat Commun 2024; 15:1222. [PMID: 38336721 PMCID: PMC10858206 DOI: 10.1038/s41467-024-45536-0] [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: 05/24/2023] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
To survive, cells must respond to changing environmental conditions. One way that eukaryotic cells react to harsh stimuli is by forming physiological, RNA-seeded subnuclear condensates, termed amyloid bodies (A-bodies). The molecular constituents of A-bodies induced by different stressors vary significantly, suggesting this pathway can tailor the cellular response by selectively aggregating a subset of proteins under a given condition. Here, we identify critical structural elements that regulate heat shock-specific amyloid aggregation. Our data demonstrates that manipulating structural pockets in constituent proteins can either induce or restrict their A-body targeting at elevated temperatures. We propose a model where selective aggregation within A-bodies is mediated by the thermal stability of a protein, with temperature-sensitive structural regions acting as an intrinsic form of post-translational regulation. This system would provide cells with a rapid and stress-specific response mechanism, to tightly control physiological amyloid aggregation or other cellular stress response pathways.
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Affiliation(s)
- Dane Marijan
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Evgenia A Momchilova
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Daniel Burns
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Sahil Chandhok
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Richard Zapf
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Holger Wille
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Davit A Potoyan
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | - Timothy E Audas
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
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5
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Fujita KI, Ito M, Irie M, Harada K, Fujiwara N, Ikeda Y, Yoshioka H, Yamazaki T, Kojima M, Mikami B, Mayeda A, Masuda S. Structural differences between the closely related RNA helicases, UAP56 and URH49, fashion distinct functional apo-complexes. Nat Commun 2024; 15:455. [PMID: 38225262 PMCID: PMC10789772 DOI: 10.1038/s41467-023-44217-8] [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: 04/23/2023] [Accepted: 12/05/2023] [Indexed: 01/17/2024] Open
Abstract
mRNA export is an essential pathway for the regulation of gene expression. In humans, closely related RNA helicases, UAP56 and URH49, shape selective mRNA export pathways through the formation of distinct complexes, known as apo-TREX and apo-AREX complexes, and their subsequent remodeling into similar ATP-bound complexes. Therefore, defining the unidentified components of the apo-AREX complex and elucidating the molecular mechanisms underlying the formation of distinct apo-complexes is key to understanding their functional divergence. In this study, we identify additional apo-AREX components physically and functionally associated with URH49. Furthermore, by comparing the structures of UAP56 and URH49 and performing an integrated analysis of their chimeric mutants, we exhibit unique structural features that would contribute to the formation of their respective complexes. This study provides insights into the specific structural and functional diversification of these two helicases that diverged from the common ancestral gene Sub2.
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Affiliation(s)
- Ken-Ichi Fujita
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan.
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan.
- Division of Cancer Stem Cell, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
| | - Misa Ito
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Midori Irie
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Kotaro Harada
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Naoko Fujiwara
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Yuya Ikeda
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Hanae Yoshioka
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Tomohiro Yamazaki
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Masaki Kojima
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Bunzo Mikami
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, 611-0011, Japan
- Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Seiji Masuda
- Division of Integrated Life Sciences, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8502, Japan.
- Department of Food Science and Nutrition, Faculty of Agriculture Kindai University, Nara, Nara, 631-8505, Japan.
- Agricultural Technology and Innovation Research Institute, Kindai University, Nara, Nara, 631-8505, Japan.
- Antiaging Center, Kindai University, Higashiosaka, Osaka, 577-8502, Japan.
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6
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Weis K, Hondele M. The Role of DEAD-Box ATPases in Gene Expression and the Regulation of RNA-Protein Condensates. Annu Rev Biochem 2022; 91:197-219. [PMID: 35303788 DOI: 10.1146/annurev-biochem-032620-105429] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DEAD-box ATPases constitute a very large protein family present in all cells, often in great abundance. From bacteria to humans, they play critical roles in many aspects of RNA metabolism, and due to their widespread importance in RNA biology, they have been characterized in great detail at both the structural and biochemical levels. DEAD-box proteins function as RNA-dependent ATPases that can unwind short duplexes of RNA, remodel ribonucleoprotein (RNP) complexes, or act as clamps to promote RNP assembly. Yet, it often remains enigmatic how individual DEAD-box proteins mechanistically contribute to specific RNA-processing steps. Here, we review the role of DEAD-box ATPases in the regulation of gene expression and propose that one common function of these enzymes is in the regulation of liquid-liquid phase separation of RNP condensates. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Karsten Weis
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland;
| | - Maria Hondele
- Biozentrum, University of Basel, Basel, Switzerland;
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7
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Caba L, Florea L, Gug C, Dimitriu DC, Gorduza EV. Circular RNA-Is the Circle Perfect? Biomolecules 2021; 11:biom11121755. [PMID: 34944400 PMCID: PMC8698871 DOI: 10.3390/biom11121755] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022] Open
Abstract
Circular RNA (circRNA) is a distinct class of non-coding RNA produced, in principle, using a back-splicing mechanism, conserved during evolution, with increased stability and a tissue-dependent expression. Circular RNA represents a functional molecule with roles in the regulation of transcription and splicing, microRNA sponge, and the modulation of protein–protein interaction. CircRNAs are involved in essential processes of life such as apoptosis, cell cycle, and proliferation. Due to the regulatory role (upregulation/downregulation) in pathogenic mechanisms of some diseases (including cancer), its potential roles as a biomarker or therapeutic target in these diseases were studied. This review focuses on the importance of circular RNA in cancer.
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Affiliation(s)
- Lavinia Caba
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
- Correspondence:
| | - Laura Florea
- Department of Nephrology-Internal Medicine, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Cristina Gug
- Microscopic Morphology Department, “Victor Babes” University of Medicine and Pharmacy, 300041 Timișoara, Romania;
| | - Daniela Cristina Dimitriu
- Department of Morpho-Functional Sciences II, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Eusebiu Vlad Gorduza
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
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8
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Pühringer T, Hohmann U, Fin L, Pacheco-Fiallos B, Schellhaas U, Brennecke J, Plaschka C. Structure of the human core transcription-export complex reveals a hub for multivalent interactions. eLife 2020; 9:e61503. [PMID: 33191911 PMCID: PMC7744094 DOI: 10.7554/elife.61503] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 11/13/2020] [Indexed: 12/24/2022] Open
Abstract
The export of mRNA from nucleus to cytoplasm requires the conserved and essential transcription and export (TREX) complex (THO-UAP56/DDX39B-ALYREF). TREX selectively binds mRNA maturation marks and licenses mRNA for nuclear export by loading the export factor NXF1-NXT1. How TREX integrates these marks and achieves high selectivity for mature mRNA is poorly understood. Here, we report the cryo-electron microscopy structure of the human THO-UAP56/DDX39B complex at 3.3 Å resolution. The seven-subunit THO-UAP56/DDX39B complex multimerizes into a 28-subunit tetrameric assembly, suggesting that selective recognition of mature mRNA is facilitated by the simultaneous sensing of multiple, spatially distant mRNA regions and maturation marks. Two UAP56/DDX39B RNA helicases are juxtaposed at each end of the tetramer, which would allow one bivalent ALYREF protein to bridge adjacent helicases and regulate the TREX-mRNA interaction. Our structural and biochemical results suggest a conserved model for TREX complex function that depends on multivalent interactions between proteins and mRNA.
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Affiliation(s)
- Thomas Pühringer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Ulrich Hohmann
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)ViennaAustria
| | - Laura Fin
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Belén Pacheco-Fiallos
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Ulla Schellhaas
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)ViennaAustria
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
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9
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Hu B, Yu L, Zhu N, Xie J. Cellular UAP56 interacts with the HBx protein of the hepatitis B virus and is involved in viral RNA nuclear export in hepatocytes. Exp Cell Res 2020; 390:111929. [DOI: 10.1016/j.yexcr.2020.111929] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 01/29/2023]
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10
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Morris AK, Wang Z, Ivey AL, Xie Y, Hill PS, Schey KL, Ren Y. Cellular mRNA export factor UAP56 recognizes nucleic acid binding site of influenza virus NP protein. Biochem Biophys Res Commun 2020; 525:259-264. [PMID: 32085897 DOI: 10.1016/j.bbrc.2020.02.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/09/2020] [Indexed: 02/06/2023]
Abstract
Influenza A virus nucleoprotein (NP) is a structural component that encapsulates the viral genome into the form of ribonucleoprotein complexes (vRNPs). Efficient assembly of vRNPs is critical for the virus life cycle. The assembly route from RNA-free NP to the NP-RNA polymer in vRNPs has been suggested to require a cellular factor UAP56, but the mechanism is poorly understood. Here, we characterized the interaction between NP and UAP56 using recombinant proteins and showed that UAP56 features two NP binding sites. In addition to the UAP56 core comprised of two RecA domains, we identified the N-terminal extension (NTE) of UAP56 as a previously unknown NP binding site. In particular, UAP56-NTE recognizes the nucleic acid binding region of NP. This corroborates our observation that binding of UAP56-NTE and RNA to NP is mutually exclusive. Collectively, our results reveal the molecular basis for how UAP56 acts on RNA-free NP, and provide new insights into NP-mediated influenza genome packaging.
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Affiliation(s)
- Andrew K Morris
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Zhen Wang
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA; Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Austin L Ivey
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Yihu Xie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Pate S Hill
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Kevin L Schey
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA; Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Yi Ren
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.
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11
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Xie Y, Ren Y. Mechanisms of nuclear mRNA export: A structural perspective. Traffic 2019; 20:829-840. [PMID: 31513326 DOI: 10.1111/tra.12691] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 08/26/2019] [Indexed: 12/28/2022]
Abstract
Export of mRNA from the nucleus to the cytoplasm is a critical process for all eukaryotic gene expression. As mRNA is synthesized, it is packaged with a myriad of RNA-binding proteins to form ribonucleoprotein particles (mRNPs). For each step in the processes of maturation and export, mRNPs must have the correct complement of proteins. Much of the mRNA export pathway revolves around the heterodimeric export receptor yeast Mex67•Mtr2/human NXF1•NXT1, which is recruited to signal the completion of nuclear mRNP assembly, mediates mRNP targeting/translocation through the nuclear pore complex (NPC), and is displaced at the cytoplasmic side of the NPC to release the mRNP into the cytoplasm. Directionality of the transport is governed by at least two DEAD-box ATPases, yeast Sub2/human UAP56 in the nucleus and yeast Dbp5/human DDX19 at the cytoplasmic side of the NPC, which respectively mediate the association and dissociation of Mex67•Mtr2/NXF1•NXT1 onto the mRNP. Here we review recent progress from structural studies of key constituents in different steps of nuclear mRNA export. These findings have laid the foundation for further studies to obtain a comprehensive mechanistic view of the mRNA export pathway.
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Affiliation(s)
- Yihu Xie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Yi Ren
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
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12
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Awasthi S, Verma M, Mahesh A, K Khan MI, Govindaraju G, Rajavelu A, Chavali PL, Chavali S, Dhayalan A. DDX49 is an RNA helicase that affects translation by regulating mRNA export and the levels of pre-ribosomal RNA. Nucleic Acids Res 2019; 46:6304-6317. [PMID: 29618122 PMCID: PMC6158705 DOI: 10.1093/nar/gky231] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/28/2018] [Indexed: 12/19/2022] Open
Abstract
Among the proteins predicted to be a part of the DExD box RNA helicase family, the functions of DDX49 are unknown. Here, we characterize the enzymatic activities and functions of DDX49 by comparing its properties with the well-studied RNA helicase, DDX39B. We find that DDX49 exhibits a robust ATPase and RNA helicase activity, significantly higher than that of DDX39B. DDX49 is required for the efficient export of poly (A)+ RNA from nucleus in a splicing-independent manner. Furthermore, DDX49 is a resident protein of nucleolus and regulates the steady state levels of pre-ribosomal RNA by regulating its transcription and stability. These dual functions of regulating mRNA export and pre-ribosomal RNA levels enable DDX49 to modulate global translation. Phenotypically, DDX49 promotes proliferation and colony forming potential of cells. Strikingly, DDX49 is significantly elevated in diverse cancer types suggesting that the increased abundance of DDX49 has a role in oncogenic transformation of cells. Taken together, this study shows the physiological role of DDX49 in regulating distinct steps of mRNA and pre-ribosomal RNA metabolism and hence translation and potential pathological role of its dysregulation, especially in cancers.
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Affiliation(s)
- Sharad Awasthi
- Department of Biotechnology, Pondicherry University, Puducherry 605 014, India
| | - Mamta Verma
- Department of Biotechnology, Pondicherry University, Puducherry 605 014, India
| | - Arun Mahesh
- Department of Biotechnology, Pondicherry University, Puducherry 605 014, India
| | - Mohd Imran K Khan
- Department of Biotechnology, Pondicherry University, Puducherry 605 014, India
| | - Gayathri Govindaraju
- Bacterial and Parasite Disease Biology, Rajiv Gandhi Center for Biotechnology, Trivandrum 695 014, India
| | - Arumugam Rajavelu
- Bacterial and Parasite Disease Biology, Rajiv Gandhi Center for Biotechnology, Trivandrum 695 014, India
| | - Pavithra L Chavali
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Sreenivas Chavali
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Arunkumar Dhayalan
- Department of Biotechnology, Pondicherry University, Puducherry 605 014, India
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13
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Mechanism and Regulation of Co-transcriptional mRNP Assembly and Nuclear mRNA Export. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:1-31. [DOI: 10.1007/978-3-030-31434-7_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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14
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Chen X, Wang C, Zhang X, Tian T, Zang J. Crystal structures of the N-terminal domain of the Staphylococcus aureus DEAD-box RNA helicase CshA and its complex with AMP. Acta Crystallogr F Struct Biol Commun 2018; 74:704-709. [PMID: 30387775 PMCID: PMC6213976 DOI: 10.1107/s2053230x1801292x] [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: 08/24/2018] [Accepted: 09/12/2018] [Indexed: 11/10/2022] Open
Abstract
CshA is a DEAD-box RNA helicase that belongs to the DExD/H-box family of proteins, which generally have an RNA-dependent ATPase activity. In Staphylococcus aureus, CshA was identified as a component of the RNA degradosome and plays important roles in RNA turnover. In this study, the crystal structures of the N-terminal RecA-like domain 1 of S. aureus CshA (SaCshAR1) and of its complex with AMP (SaCshAR1-AMP) are reported at resolutions of 1.5 and 1.8 Å, respectively. SaCshAR1 adopts a conserved α/β RecA-like structure with seven parallel strands surrounded by nine α-helices. The Q motif and motif I are responsible for the binding of the adenine group and phosphate group of AMP, respectively. Structure comparison of SaCshAR1-AMP and SaCshAR1 reveals that motif I undergoes a conformational change upon AMP binding. Isothermal titration calorimetry assays further conformed the essential roles of Phe22 in the Q motif and Lys52 in motif I for binding ATP, indicating a conserved substrate-binding mechanism in SaCshA compared with other DEAD-box RNA helicases.
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Affiliation(s)
- Xiaobao Chen
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, Collaborative Innovation Center of Chemistry for Life Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230027, People’s Republic of China
| | - Chengliang Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, Collaborative Innovation Center of Chemistry for Life Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230027, People’s Republic of China
| | - Xuan Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, Collaborative Innovation Center of Chemistry for Life Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230027, People’s Republic of China
| | - Tian Tian
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, Collaborative Innovation Center of Chemistry for Life Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230027, People’s Republic of China
| | - Jianye Zang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, Collaborative Innovation Center of Chemistry for Life Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230027, People’s Republic of China
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15
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Xu L, Wang L, Peng J, Li F, Wu L, Zhang B, Lv M, Zhang J, Gong Q, Zhang R, Zuo X, Zhang Z, Wu J, Tang Y, Shi Y. Insights into the Structure of Dimeric RNA Helicase CsdA and Indispensable Role of Its C-Terminal Regions. Structure 2017; 25:1795-1808.e5. [PMID: 29107486 DOI: 10.1016/j.str.2017.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/21/2017] [Accepted: 09/20/2017] [Indexed: 02/06/2023]
Abstract
CsdA has been proposed to be essential for the biogenesis of ribosome and gene regulation after cold shock. However, the structure of CsdA and the function of its long C-terminal regions are still unclear. Here, we solved all of the domain structures of CsdA and found two previously uncharacterized auxiliary domains: a dimerization domain (DD) and an RNA-binding domain (RBD). Small-angle X-ray scattering experiments helped to track the conformational flexibilities of the helicase core domains and C-terminal regions. Biochemical assays revealed that DD is indispensable for stabilizing the CsdA dimeric structure. We also demonstrate for the first time that CsdA functions as a stable dimer at low temperature. The C-terminal regions are critical for RNA binding and efficient enzymatic activities. CsdA_RBD could specifically bind to the regions with a preference for single-stranded G-rich RNA, which may help to bring the helicase core to unwind the adjacent duplex.
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Affiliation(s)
- Ling Xu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Lijun Wang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Junhui Peng
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Fudong Li
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Lijie Wu
- National Center for Protein Science Shanghai, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Beibei Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Mengqi Lv
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jiahai Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Qingguo Gong
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Rongguang Zhang
- National Center for Protein Science Shanghai, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaobing Zuo
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60349, USA
| | - Zhiyong Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jihui Wu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yajun Tang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
| | - Yunyu Shi
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
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16
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Cellular splicing factor UAP56 stimulates trimeric NP formation for assembly of functional influenza viral ribonucleoprotein complexes. Sci Rep 2017; 7:14053. [PMID: 29070793 PMCID: PMC5656576 DOI: 10.1038/s41598-017-13784-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 10/02/2017] [Indexed: 12/02/2022] Open
Abstract
The influenza virus RNA genome exists as a ribonucleoprotein (RNP) complex by interacting with NP, one of virus-encoded RNA binding proteins. It is proposed that trimeric NP is a functional form, but it is not clear how trimeric NP is formed and transferred to RNA. UAP56, a cellular splicing factor, functions as a molecular chaperone for NP and is required for the replication-coupled RNP formation of newly synthesized viral genome, but the details of NP transfer to viral RNA by UAP56 is unclear. Here we found that UAP56 is complexed with trimeric NP, but not monomeric NP. Gel filtration analysis and atomic force microscopy analysis indicated that the complex consists of two trimeric NP connected by UAP56. We also found that UAP56 stimulates trimeric NP formation from monomeric NP even at physiological salt concentrations. Thus, UAP56 facilitates the transfer of NP to viral RNA since trimeric NP has higher RNA binding activity than monomeric NP. Further, UAP56 represses the binding of excess amount of NP to RNA possibly by transferring trimeric NP. Collectively, we propose that UAP56 stimulates viral RNP formation through promotion of the assembly of trimeric NP and is important for the structural integrity of NP-RNA complex.
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17
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Espinosa S, Zhang L, Li X, Zhao R. Understanding pre-mRNA splicing through crystallography. Methods 2017; 125:55-62. [PMID: 28506657 PMCID: PMC5546983 DOI: 10.1016/j.ymeth.2017.04.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 04/11/2017] [Accepted: 04/26/2017] [Indexed: 01/07/2023] Open
Abstract
Crystallography is a powerful tool to determine the atomic structures of proteins and RNAs. X-ray crystallography has been used to determine the structure of many splicing related proteins and RNAs, making major contributions to our understanding of the molecular mechanism and regulation of pre-mRNA splicing. Compared to other structural methods, crystallography has its own advantage in the high-resolution structural information it can provide and the unique biological questions it can answer. In addition, two new crystallographic methods - the serial femtosecond crystallography and 3D electron crystallography - were developed to overcome some of the limitations of traditional X-ray crystallography and broaden the range of biological problems that crystallography can solve. This review discusses the theoretical basis, instrument requirements, troubleshooting, and exciting potential of these crystallographic methods to further our understanding of pre-mRNA splicing, a critical event in gene expression of all eukaryotes.
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18
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Studying structure and function of spliceosomal helicases. Methods 2017; 125:63-69. [PMID: 28668587 DOI: 10.1016/j.ymeth.2017.06.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/21/2017] [Accepted: 06/24/2017] [Indexed: 12/27/2022] Open
Abstract
The splicing of eukaryotic precursor mRNAs requires the activity of at least three DEAD-box helicases, one Ski2-like helicase and four DEAH-box helicases. High resolution structures for five of these spliceosomal helicases were obtained by means of X-ray crystallography. Additional low resolution structural information could be derived from single particle cryo electron microscopy and small angle X-ray scattering. The functional characterization includes biochemical methods to measure the ATPase and helicase activities. This review gives an overview on the techniques used to gain insights in to the structure and function of spliceosomal helicases.
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19
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Bittencourt IDA, Serpeloni M, Hiraiwa PM, de Arruda Campos Brasil de Souza T, Ávila AR. Dissecting biochemical peculiarities of the ATPase activity of TcSub2, a component of the mRNA export pathway in Trypanosoma cruzi. Int J Biol Macromol 2017; 98:793-801. [PMID: 28212935 DOI: 10.1016/j.ijbiomac.2017.02.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/10/2017] [Accepted: 02/11/2017] [Indexed: 11/16/2022]
Abstract
The RNA helicase DEAD-box protein Sub2 (yeast)/UAP56 (mammals) is conserved across eukaryotes and is essential for mRNA export in trypanosomes. Despite the high conservation of Sub2 in lower eukaryotes such as Trypanosoma cruzi, the low conservation of other mRNA export factors raises questions regarding whether the mode of action of TcSub2 is similar to that of orthologs from other eukaryotes. Mutation of the conserved K87 residue of TcSub2 abolishes ATPase activity, showing that its ATPase domain is functional. However, the Vmax of TcSub2 was much higher than the Vmax described for the human protein UAP56, which suggests that the TcSub2 enzyme hydrolyzes ATP faster than its human homolog. Furthermore, we demonstrate that RNA association is less important to the activity of TcSub2 compared to UAP56. Our results show differences in activity of this protein, even though the structure of TcSub2 is very similar to UAP56. Functional complementation assays indicate that these differences may be common to other trypanosomatids. Distinct features of RNA influence and ATPase efficiency between UAP56 and TcSub2 may reflect distinct structures for functional sites of TcSub2. For this reason, ligand-based or structure-based methodologies can be applied to investigate the potential of TcSub2 as a target for new drugs.
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20
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Ren Y, Schmiege P, Blobel G. Structural and biochemical analyses of the DEAD-box ATPase Sub2 in association with THO or Yra1. eLife 2017; 6. [PMID: 28059701 PMCID: PMC5218534 DOI: 10.7554/elife.20070] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 12/22/2016] [Indexed: 01/08/2023] Open
Abstract
mRNA is cotranscrptionally processed and packaged into messenger ribonucleoprotein particles (mRNPs) in the nucleus. Prior to export through the nuclear pore, mRNPs undergo several obligatory remodeling reactions. In yeast, one of these reactions involves loading of the mRNA-binding protein Yra1 by the DEAD-box ATPase Sub2 as assisted by the hetero-pentameric THO complex. To obtain molecular insights into reaction mechanisms, we determined crystal structures of two relevant complexes: a THO hetero-pentamer bound to Sub2 at 6.0 Å resolution; and Sub2 associated with an ATP analogue, RNA, and a C-terminal fragment of Yra1 (Yra1-C) at 2.6 Å resolution. We found that the 25 nm long THO clamps Sub2 in a half-open configuration; in contrast, when bound to the ATP analogue, RNA and Yra1-C, Sub2 assumes a closed conformation. Both THO and Yra1-C stimulated Sub2’s intrinsic ATPase activity. We propose that THO surveys common landmarks in each nuclear mRNP to localize Sub2 for targeted loading of Yra1. DOI:http://dx.doi.org/10.7554/eLife.20070.001
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Affiliation(s)
- Yi Ren
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Philip Schmiege
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Günter Blobel
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
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21
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Schumann S, Jackson BR, Yule I, Whitehead SK, Revill C, Foster R, Whitehouse A. Targeting the ATP-dependent formation of herpesvirus ribonucleoprotein particle assembly as an antiviral approach. Nat Microbiol 2016; 2:16201. [PMID: 27798559 DOI: 10.1038/nmicrobiol.2016.201] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/01/2016] [Indexed: 12/16/2022]
Abstract
Human herpesviruses are responsible for a range of debilitating acute and recurrent diseases, including a number of malignancies. Current treatments are limited to targeting the herpesvirus DNA polymerases, but with emerging viral resistance and little efficacy against the oncogenic herpesviruses, there is an urgent need for new antiviral strategies. Here, we describe a mechanism to inhibit the replication of the oncogenic herpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV), by targeting the ATP-dependent formation of viral ribonucleoprotein particles (vRNPs). We demonstrate that small-molecule inhibitors which selectively inhibit the ATPase activity of the cellular human transcription/export complex (hTREX) protein UAP56 result in effective inhibition of vRNP formation, viral lytic replication and infectious virion production. Strikingly, as all human herpesviruses use conserved mRNA processing pathways involving hTREX components, we demonstrate the feasibility of this approach for pan-herpesvirus inhibition.
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Affiliation(s)
- Sophie Schumann
- School of Molecular and Cellular Biology, Leeds LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, Leeds LS2 9JT, UK
| | - Brian R Jackson
- School of Molecular and Cellular Biology, Leeds LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, Leeds LS2 9JT, UK
| | - Ian Yule
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | | | | | - Richard Foster
- Astbury Centre for Structural Molecular Biology, Leeds LS2 9JT, UK
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Adrian Whitehouse
- School of Molecular and Cellular Biology, Leeds LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, Leeds LS2 9JT, UK
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22
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De I, Schmitzová J, Pena V. The organization and contribution of helicases to RNA splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:259-74. [PMID: 26874649 DOI: 10.1002/wrna.1331] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 12/08/2015] [Accepted: 12/09/2015] [Indexed: 12/27/2022]
Abstract
Splicing is an essential step of gene expression. It occurs in two consecutive chemical reactions catalyzed by a large protein-RNA complex named the spliceosome. Assembled on the pre-mRNA substrate from five small nuclear proteins, the spliceosome acts as a protein-controlled ribozyme to catalyze the two reactions and finally dissociates into its components, which are re-used for a new round of splicing. Upon following this cyclic pathway, the spliceosome undergoes numerous intermediate stages that differ in composition as well as in their internal RNA-RNA and RNA-protein contacts. The driving forces and control mechanisms of these remodeling processes are provided by specific molecular motors called RNA helicases. While eight spliceosomal helicases are present in all organisms, higher eukaryotes contain five additional ones potentially required to drive a more intricate splicing pathway and link it to an RNA metabolism of increasing complexity. Spliceosomal helicases exhibit a notable structural diversity in their accessory domains and overall architecture, in accordance with the diversity of their task-specific functions. This review summarizes structure-function knowledge about all spliceosomal helicases, including the latter five, which traditionally are treated separately from the conserved ones. The implications of the structural characteristics of helicases for their functions, as well as for their structural communication within the multi-subunits environment of the spliceosome, are pointed out.
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Affiliation(s)
- Inessa De
- Macromolecular Crystallography Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Jana Schmitzová
- Macromolecular Crystallography Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vladimir Pena
- Macromolecular Crystallography Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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23
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Bol GM, Xie M, Raman V. DDX3, a potential target for cancer treatment. Mol Cancer 2015; 14:188. [PMID: 26541825 PMCID: PMC4636063 DOI: 10.1186/s12943-015-0461-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/22/2015] [Indexed: 12/27/2022] Open
Abstract
RNA helicases are a large family of proteins with a distinct motif, referred to as the DEAD/H (Asp-Glu-Ala-Asp/His). The exact functions of all the human DEAD/H box proteins are unknown. However, it has been consistently demonstrated that these proteins are associated with several aspects of energy-dependent RNA metabolism, including translation, ribosome biogenesis, and pre-mRNA splicing. In addition, DEAD/H box proteins participate in nuclear-cytoplasmic transport and organellar gene expression. A member of this RNA helicase family, DDX3, has been identified in a variety of cellular biogenesis processes, including cell-cycle regulation, cellular differentiation, cell survival, and apoptosis. In cancer, DDX3 expression has been evaluated in patient samples of breast, lung, colon, oral, and liver cancer. Both tumor suppressor and oncogenic functions have been attributed to DDX3 and are discussed in this review. In general, there is concordance with in vitro evidence to support the hypothesis that DDX3 is associated with an aggressive phenotype in human malignancies. Interestingly, very few cancer types harbor mutations in DDX3, which result in altered protein function rather than a loss of function. Efficacy of drugs to curtail cancer growth is hindered by adaptive responses that promote drug resistance, eventually leading to treatment failure. One way to circumvent development of resistant disease is to develop novel drugs that target over-expressed proteins involved in this adaptive response. Moreover, if the target gene is developmentally regulated, there is less of a possibility to abruptly accumulate mutations leading to drug resistance. In this regard, DDX3 could be a druggable target for cancer treatment. We present an overview of DDX3 biology and the currently available DDX3 inhibitors for cancer treatment.
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Affiliation(s)
- Guus Martinus Bol
- Department of Pathology, University Medical Center Utrecht Cancer Center, 3508 GA, Utrecht, The Netherlands.,Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 340, Baltimore, MD, 21205, USA
| | - Min Xie
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 340, Baltimore, MD, 21205, USA
| | - Venu Raman
- Department of Pathology, University Medical Center Utrecht Cancer Center, 3508 GA, Utrecht, The Netherlands. .,Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 340, Baltimore, MD, 21205, USA. .,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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24
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Tuteja N, Tarique M, Trivedi DK, Sahoo RK, Tuteja R. Stress-induced Oryza sativa BAT1 dual helicase exhibits unique bipolar translocation. PROTOPLASMA 2015; 252:1563-1574. [PMID: 25772680 DOI: 10.1007/s00709-015-0791-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 03/02/2015] [Indexed: 06/04/2023]
Abstract
HLA-B associated transcript 1 (BAT1) protein, also named as spliceosome RNA helicase UAP56, is a member of the DExD/H-box family of helicases. However, regulation under stress, biochemical properties, and functions of plant homologue of BAT1 are poorly understood. Here, we report the purification and detailed biochemical characterization of the Oryza sativa homologue of BAT1 (OsBAT1/UAP56) protein (52 kDa) and regulation of its transcript under abiotic stress. OsBAT1 transcript levels are enhanced in rice seedlings in response to abiotic stress including salt stress and abscisic acid. Purified OsBAT1 protein exhibits the DNA- and RNA-dependent ATPase, RNA helicase, and DNA- and RNA-binding activities. Interestingly OsBAT1 also exhibits unique DNA helicase activity, which has not been reported so far in any BAT1 homologue. Moreover, OsBAT1 translocates in both the 3' to 5' and 5' to 3' directions, which is also a unique property. The K m value for OsBAT1 DNA helicase is 0.9753 nM and for RNA helicase is 1.7536 nM, respectively. This study demonstrates several unique characteristics of OsBAT1 especially its ability to unwind both DNA and RNA duplexes; bipolar translocation and its transcript upregulation under abiotic stresses indicate that it is a multifunctional protein. Overall, this study represents significant contribution in advancing our knowledge regarding functions of OsBAT1 in RNA and DNA metabolism and its putative role in abiotic stress signaling in plants.
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Affiliation(s)
- Narendra Tuteja
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Mohammed Tarique
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Dipesh Kumar Trivedi
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Ranjan Kumar Sahoo
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Renu Tuteja
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
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25
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Seo M, Seo K, Hwang W, Koo HJ, Hahm JH, Yang JS, Han SK, Hwang D, Kim S, Jang SK, Lee Y, Nam HG, Lee SJV. RNA helicase HEL-1 promotes longevity by specifically activating DAF-16/FOXO transcription factor signaling in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2015; 112:E4246-55. [PMID: 26195740 PMCID: PMC4534234 DOI: 10.1073/pnas.1505451112] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The homeostatic maintenance of the genomic DNA is crucial for regulating aging processes. However, the role of RNA homeostasis in aging processes remains unknown. RNA helicases are a large family of enzymes that regulate the biogenesis and homeostasis of RNA. However, the functional significance of RNA helicases in aging has not been explored. Here, we report that a large fraction of RNA helicases regulate the lifespan of Caenorhabditis elegans. In particular, we show that a DEAD-box RNA helicase, helicase 1 (HEL-1), promotes longevity by specifically activating the DAF-16/forkhead box O (FOXO) transcription factor signaling pathway. We find that HEL-1 is required for the longevity conferred by reduced insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) and is sufficient for extending lifespan. We further show that the expression of HEL-1 in the intestine and neurons contributes to longevity. HEL-1 enhances the induction of a large fraction of DAF-16 target genes. Thus, the RNA helicase HEL-1 appears to promote longevity in response to decreased IIS as a transcription coregulator of DAF-16. Because HEL-1 and IIS are evolutionarily well conserved, a similar mechanism for longevity regulation via an RNA helicase-dependent regulation of FOXO signaling may operate in mammals, including humans.
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Affiliation(s)
- Mihwa Seo
- Center for Plant Aging Research, Institute for Basic Science, Daegu 711-873, Korea; School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Keunhee Seo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Wooseon Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Hee Jung Koo
- Center for Plant Aging Research, Institute for Basic Science, Daegu 711-873, Korea; School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Jeong-Hoon Hahm
- Center for Plant Aging Research, Institute for Basic Science, Daegu 711-873, Korea
| | - Jae-Seong Yang
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Seong Kyu Han
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Daehee Hwang
- Center for Plant Aging Research, Institute for Basic Science, Daegu 711-873, Korea; Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea
| | - Sanguk Kim
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology, Pohang 790-784, Korea; Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea; Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea
| | - Sung Key Jang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Yoontae Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science, Daegu 711-873, Korea; Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea;
| | - Seung-Jae V Lee
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology, Pohang 790-784, Korea; Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea; Information Technology Convergence Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea
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26
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Newo ANS. Molecular modeling of the Plasmodium falciparum pre-mRNA splicing and nuclear export factor PfU52. Protein J 2015; 33:354-68. [PMID: 24861003 DOI: 10.1007/s10930-014-9566-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
UAP56/SUB2 is a DExD/H-box RNA helicase that is critically involved in pre-mRNA splicing and mRNA nuclear export. This helicase is broadly conserved and essential in many eukaryotic lineages, including protozoan and metazoan parasites. Previous research suggests that helicases from parasites could be promising drug targets for treating parasitic diseases. Accordingly, characterizing the structure and function of these proteins is of interest for structure-based, de novo design of new lead compounds. Here, we used homology modeling to construct a three-dimensional structure of PfU52 (PMDB ID: PM0079288), the Plasmodium falciparum ortholog of UAP56/SUB2, and explored the detailed architecture of its functional sites. Comparative in silico analysis revealed that although PfU52 shared many physicochemical, structural and dynamic similarities with its human homolog, it also displayed some unique features that could be exploited for drug design.
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Affiliation(s)
- Alain N S Newo
- Beckman Research Institute of City of Hope, Duarte, CA, USA,
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27
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Ozgur S, Buchwald G, Falk S, Chakrabarti S, Prabu JR, Conti E. The conformational plasticity of eukaryotic RNA-dependent ATPases. FEBS J 2015; 282:850-63. [PMID: 25645110 DOI: 10.1111/febs.13198] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 12/22/2022]
Abstract
RNA helicases are present in all domains of life and participate in almost all aspects of RNA metabolism, from transcription and processing to translation and decay. The diversity of pathways and substrates that they act on is reflected in the diversity of their individual functions, structures, and mechanisms. However, RNA helicases also share hallmark properties. At the functional level, they promote rearrangements of RNAs and RNP particles by coupling nucleic acid binding and release with ATP hydrolysis. At the molecular level, they contain two domains homologous to the bacterial RecA recombination protein. This conserved catalytic core is flanked by additional domains, which typically regulate the ATPase activity in cis. Binding to effector proteins targets or regulates the ATPase activity in trans. Structural and biochemical studies have converged on the plasticity of RNA helicases as a fundamental property that is used to control their timely activation in the cell. In this review, we focus on the conformational regulation of conserved eukaryotic RNA helicases.
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Affiliation(s)
- Sevim Ozgur
- Structural Cell Biology Department, Max Planck Institute of Biochemistry, Martinsried, Germany
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28
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Ostareck DH, Naarmann-de Vries IS, Ostareck-Lederer A. DDX6 and its orthologs as modulators of cellular and viral RNA expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:659-78. [PMID: 24788243 DOI: 10.1002/wrna.1237] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 03/19/2014] [Accepted: 03/21/2014] [Indexed: 12/21/2022]
Abstract
DDX6 (Rck/p54), a member of the DEAD-box family of helicases, is highly conserved from unicellular eukaryotes to vertebrates. Functions of DDX6 and its orthologs in dynamic ribonucleoproteins contribute to global and transcript-specific messenger RNA (mRNA) storage, translational repression, and decay during development and differentiation in the germline and somatic cells. Its role in pathways that promote mRNA-specific alternative translation initiation has been shown to be linked to cellular homeostasis, deregulated tissue development, and the control of gene expression in RNA viruses. Recently, DDX6 was found to participate in mRNA regulation mediated by miRNA-mediated silencing. DDX6 and its orthologs have versatile functions in mRNA metabolism, which characterize them as important post-transcriptional regulators of gene expression.
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Affiliation(s)
- Dirk H Ostareck
- Experimental Research Unit, Department of Intensive Care and Intermediate Care, University Hospital, RWTH Aachen University, Aachen, Germany
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29
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Wang Z, Gao J, Song H, Wu X, Sun Y, Qi J, Yu H, Wang Z, Zhang Q. Sexually dimorphic expression of vasa isoforms in the tongue sole (Cynoglossus semilaevis). PLoS One 2014; 9:e93380. [PMID: 24671276 PMCID: PMC3966880 DOI: 10.1371/journal.pone.0093380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 03/03/2014] [Indexed: 11/19/2022] Open
Abstract
The vasa gene encodes an ATP-dependent RNA helicase of the DEAD box protein family that functions in a broad range of molecular events involving duplex RNA. In most species, the germline specific expression of vasa becomes a molecular marker widely used in the visualization and labeling of primordial germ cells (PGCs) and a tool in surrogate broodstock production through PGC transplantation. The vasa gene from tongue sole (Cynoglossus semilaevis) was characterized to promote the development of genetic breeding techniques in this species. Three C. semilaevis vasa transcripts were isolated, namely vas-l, vas-m, and vas-s. Quantitative real-time PCR results showed that C. semilaevis vasa transcripts were prevalently expressed in gonads, with very weak expression of vas-s in other tissues. Embryonic development expression profiles revealed the onset of zygotic transcription of vasa mRNAs and the maternal deposit of the three transcripts. The genetic ZW female juvenile fish was discriminated from genetic ZZ males by a pair of female specific primers. Only the expression of vas-s can be observed in both sexes during early gonadal differentiation. Before PGCs started mitosis, there was sexually dimorphic expression of vas-s with the ovary showing higher levels and downward trend. The results demonstrated the benefits of vasa as a germline specific marker for PGCs during embryonic development and gonadal differentiation. This study lays the groundwork for further application of C. semilaevis PGCs in fish breeding.
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Affiliation(s)
- Zhongkai Wang
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jinning Gao
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Huayu Song
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiaomeng Wu
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yan Sun
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jie Qi
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Haiyang Yu
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zhigang Wang
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Quanqi Zhang
- Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- * E-mail:
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30
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Abstract
Superfamily 2 helicase proteins are ubiquitous in RNA biology and have an extraordinarily broad set of functional roles. Central among these roles are the promotion of rearrangements of structured RNAs and the remodeling of ribonucleoprotein complexes (RNPs), allowing formation of native RNA structure or progression through a functional cycle of structures. Although all superfamily 2 helicases share a conserved helicase core, they are divided evolutionarily into several families, and it is principally proteins from three families, the DEAD-box, DEAH/RHA, and Ski2-like families, that function to manipulate structured RNAs and RNPs. Strikingly, there are emerging differences in the mechanisms of these proteins, both between families and within the largest family (DEAD-box), and these differences appear to be tuned to their RNA or RNP substrates and their specific roles. This review outlines basic mechanistic features of the three families and surveys individual proteins and the current understanding of their biological substrates and mechanisms.
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Affiliation(s)
- Inga Jarmoskaite
- Department of Molecular Biosciences and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712; ,
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31
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Liu F, Putnam AA, Jankowsky E. DEAD-box helicases form nucleotide-dependent, long-lived complexes with RNA. Biochemistry 2014; 53:423-33. [PMID: 24367975 DOI: 10.1021/bi401540q] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DEAD-box RNA helicases bind and remodel RNA and RNA-protein complexes in an ATP-dependent fashion. Several lines of evidence suggest that DEAD-box RNA helicases can also form stable, persistent complexes with RNA in a process referred to as RNA clamping. The molecular basis of RNA clamping is not well understood. Here we show that the yeast DEAD-box helicase Ded1p forms exceptionally long-lived complexes with RNA and the nonhydrolyzable ATP ground-state analogue ADP-BeFx or the nonhydrolyzable ATP transition state analogue ADP-AlFx. The complexes have lifetimes of several hours, and neither nucleotide nor Mg(2+) is released during this period. Mutation of arginine 489, which stabilizes the transition state, prevents formation of long-lived complexes with the ATP transition state analogue, but not with the ground state analogue. We also show that two other yeast DEAD-box helicases, Mss116p and Sub2p, form comparably long-lived complexes with RNA and ADP-BeFx. Like Ded1p, Mss116p forms long-lived complexes with ADP-AlFx, but Sub2p does not. These data suggest that the ATP transition state might vary for distinct DEAD-box helicases, or that the transition state triggers differing RNA binding properties in these proteins. In the ATP ground state, however, all tested DEAD-box helicases establish a persistent grip on RNA, revealing an inherent capacity of the enzymes to function as potent, ATP-dependent RNA clamps.
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Affiliation(s)
- Fei Liu
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, Jiangsu, 210095, China
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32
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Zhang ZM, Yang F, Zhang J, Tang Q, Li J, Gu J, Zhou J, Xu YZ. Crystal structure of Prp5p reveals interdomain interactions that impact spliceosome assembly. Cell Rep 2013; 5:1269-78. [PMID: 24290758 DOI: 10.1016/j.celrep.2013.10.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 09/30/2013] [Accepted: 10/29/2013] [Indexed: 01/13/2023] Open
Abstract
The DEAD-box adenosine triphosphatase (ATPase) Prp5p facilitates U2 small nuclear ribonucleoprotein particle (snRNP) binding to the intron branch site region during spliceosome assembly. We present crystal structures of S. cerevisiae Prp5p alone and in complex with ADP at 2.12 Å and 1.95 Å resolution. The three-dimensional packing of Prp5p subdomains differs strikingly from that so far observed in other DEAD-box proteins: two RecA-like subdomains adopt an "open state" conformation stabilized by extensive interactions involving sequences that flank the two subdomains. This conformation is distinct from that required for ATP hydrolysis. Consistent with this, Prp5p mutations that destabilize interdomain interactions exhibited increased ATPase activity in vitro and inhibited splicing of suboptimal branch site substrates in vivo, whereas restoration of interdomain interactions reversed these effects. We conclude that the Prp5p open state conformation is biologically relevant and that disruption of the interdomain interaction facilitates a large-scale conformational change of Prp5p during U2 snRNP-branch site recognition.
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Affiliation(s)
- Zhi-Min Zhang
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Fei Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jinru Zhang
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Qing Tang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jie Li
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jing Gu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jiahai Zhou
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Yong-Zhen Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
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33
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Yang H, Lowenson JD, Clarke S, Zubarev RA. Brain proteomics supports the role of glutamate metabolism and suggests other metabolic alterations in protein l-isoaspartyl methyltransferase (PIMT)-knockout mice. J Proteome Res 2013; 12:4566-76. [PMID: 23947766 DOI: 10.1021/pr400688r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Protein l-isoaspartyl methyltransferase (PIMT) repairs the isoaspartyl residues (isoAsp) that originate from asparagine deamidation and aspartic acid (Asp) isomerization to Asp residues. Deletion of the gene encoding PIMT in mice (Pcmt1) leads to isoAsp accumulation in all tissues measured, especially in the brain. These PIMT-knockout (PIMT-KO) mice have perturbed glutamate metabolism and die prematurely of epileptic seizures. To elucidate the role of PIMT further, brain proteomes of PIMT-KO mice and controls were analyzed. The isoAsp levels from two of the detected 67 isoAsp sites (residue 98 from calmodulin and 68 from glyceraldehyde-3-phosphate dehydrogenase) were quantified and found to be significantly increased in PIMT-KO mice (p < 0.01). Additionally, the abundance of at least 151 out of the 1017 quantified proteins was found to be altered in PIMT-KO mouse brains. Gene ontology analysis revealed that many down-regulated proteins are involved in cellular amino acid biosynthesis. For example, the serine synthesis pathway was suppressed, possibly leading to reduced serine production in PIMT-KO mice. Additionally, the abundances of enzymes in the glutamate-glutamine cycle were altered toward the accumulation of glutamate. These findings support the involvement of PIMT in glutamate metabolism and suggest that the absence of PIMT also affects other processes involving amino acid synthesis and metabolism.
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Affiliation(s)
- Hongqian Yang
- Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Scheeles väg 2, SE-17 177 Stockholm, Sweden
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34
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Geißler V, Altmeyer S, Stein B, Uhlmann-Schiffler H, Stahl H. The RNA helicase Ddx5/p68 binds to hUpf3 and enhances NMD of Ddx17/p72 and Smg5 mRNA. Nucleic Acids Res 2013; 41:7875-88. [PMID: 23788676 PMCID: PMC3763533 DOI: 10.1093/nar/gkt538] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Non-sense-mediated mRNA decay (NMD) is a mechanism of translation-dependent mRNA surveillance in eukaryotes: it degrades mRNAs with premature termination codons (PTCs) and contributes to cellular homeostasis by downregulating a number of physiologically important mRNAs. In the NMD pathway, Upf proteins, a set of conserved factors of which Upf1 is the central regulator, recruit decay enzymes to promote RNA cleavage. In mammals, the degradation of PTC-containing mRNAs is triggered by the exon–junction complex (EJC) through binding of its constituents Upf2 and Upf3 to Upf1. The complex formed eventually induces translational repression and recruitment of decay enzymes. Mechanisms by which physiological mRNAs are targeted by the NMD machinery in the absence of an EJC have been described but still are discussed controversially. Here, we report that the DEAD box proteins Ddx5/p68 and its paralog Ddx17/p72 also bind the Upf complex by physical interaction with Upf3, thereby interfering with the binding of EJC. By activating the NMD machinery, Ddx5 is shown to regulate the expression of its own, Ddx17 and Smg5 mRNAs. For NMD triggering, the adenosine triphosphate-binding activity of Ddx5 and the 3′-untranslated region of substrate mRNAs are essential.
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Affiliation(s)
- Verena Geißler
- Department of Medical Biochemistry and Molecular Biology, University of Saarland, Medical Center, Building 45, 66421 Homburg, Germany
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35
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Putnam AA, Jankowsky E. AMP sensing by DEAD-box RNA helicases. J Mol Biol 2013; 425:3839-45. [PMID: 23702290 DOI: 10.1016/j.jmb.2013.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/10/2013] [Accepted: 05/14/2013] [Indexed: 11/18/2022]
Abstract
In eukaryotes, cellular levels of adenosine monophosphate (AMP) signal the metabolic state of the cell. AMP concentrations increase significantly upon metabolic stress, such as glucose deprivation in yeast. Here, we show that several DEAD-box RNA helicases are sensitive to AMP, which is not produced during ATP hydrolysis by these enzymes. We find that AMP potently inhibits RNA binding and unwinding by the yeast DEAD-box helicases Ded1p, Mss116p, and eIF4A. However, the yeast DEAD-box helicases Sub2p and Dbp5p are not inhibited by AMP. Our observations identify a subset of DEAD-box helicases as enzymes with the capacity to directly link changes in AMP concentrations to RNA metabolism.
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Affiliation(s)
- Andrea A Putnam
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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36
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Zhang L, Li X, Zhao R. Structural analyses of the pre-mRNA splicing machinery. Protein Sci 2013; 22:677-92. [PMID: 23592432 DOI: 10.1002/pro.2266] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/03/2023]
Abstract
Pre-mRNA splicing is a critical event in the gene expression pathway of all eukaryotes. The splicing reaction is catalyzed by the spliceosome, a huge protein-RNA complex that contains five snRNAs and hundreds of different protein factors. Understanding the structure of this large molecular machinery is critical for understanding its function. Although the highly dynamic nature of the spliceosome, in both composition and conformation, posed daunting challenges to structural studies, there has been significant recent progress on structural analyses of the splicing machinery, using electron microscopy, crystallography, and nuclear magnetic resonance. This review discusses key recent findings in the structural analyses of the spliceosome and its components and how these findings advance our understanding of the function of the splicing machinery.
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Affiliation(s)
- Lingdi Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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37
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Putnam AA, Jankowsky E. DEAD-box helicases as integrators of RNA, nucleotide and protein binding. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:884-93. [PMID: 23416748 DOI: 10.1016/j.bbagrm.2013.02.002] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 01/10/2023]
Abstract
DEAD-box helicases perform diverse cellular functions in virtually all steps of RNA metabolism from Bacteria to Humans. Although DEAD-box helicases share a highly conserved core domain, the enzymes catalyze a wide range of biochemical reactions. In addition to the well established RNA unwinding and corresponding ATPase activities, DEAD-box helicases promote duplex formation and displace proteins from RNA. They can also function as assembly platforms for larger ribonucleoprotein complexes, and as metabolite sensors. This review aims to provide a perspective on the diverse biochemical features of DEAD-box helicases and connections to structural information. We discuss these data in the context of a model that views the enzymes as integrators of RNA, nucleotide, and protein binding. This article is part of a Special Issue entitled: The Biology of RNA helicases - Modulation for life.
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Affiliation(s)
- Andrea A Putnam
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
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38
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Zhang F, Wang J, Xu J, Zhang Z, Koppetsch BS, Schultz N, Vreven T, Meignin C, Davis I, Zamore PD, Weng Z, Theurkauf WE. UAP56 couples piRNA clusters to the perinuclear transposon silencing machinery. Cell 2013; 151:871-884. [PMID: 23141543 DOI: 10.1016/j.cell.2012.09.040] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 03/09/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022]
Abstract
piRNAs silence transposons during germline development. In Drosophila, transcripts from heterochromatic clusters are processed into primary piRNAs in the perinuclear nuage. The nuclear DEAD box protein UAP56 has been previously implicated in mRNA splicing and export, whereas the DEAD box protein Vasa has an established role in piRNA production and localizes to nuage with the piRNA binding PIWI proteins Ago3 and Aub. We show that UAP56 colocalizes with the cluster-associated HP1 variant Rhino, that nuage granules containing Vasa localize directly across the nuclear envelope from cluster foci containing UAP56 and Rhino, and that cluster transcripts immunoprecipitate with both Vasa and UAP56. Significantly, a charge-substitution mutation that alters a conserved surface residue in UAP56 disrupts colocalization with Rhino, germline piRNA production, transposon silencing, and perinuclear localization of Vasa. We therefore propose that UAP56 and Vasa function in a piRNA-processing compartment that spans the nuclear envelope.
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Affiliation(s)
- Fan Zhang
- Program in Cell and Developmental Dynamics, University of Massachusetts Medical School, Worcester, MA 01655, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jie Wang
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jia Xu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Zhao Zhang
- Program in Cell and Developmental Dynamics, University of Massachusetts Medical School, Worcester, MA 01655, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Birgit S Koppetsch
- Program in Cell and Developmental Dynamics, University of Massachusetts Medical School, Worcester, MA 01655, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Nadine Schultz
- Program in Cell and Developmental Dynamics, University of Massachusetts Medical School, Worcester, MA 01655, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Thom Vreven
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Carine Meignin
- Centre National de la Recherche Scientifique, Unité Propre de Recherche 9022, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67 084 Strasbourg Cedex, France
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Phillip D Zamore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Howard Hughes Medical Institute
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
| | - William E Theurkauf
- Program in Cell and Developmental Dynamics, University of Massachusetts Medical School, Worcester, MA 01655, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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39
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Bruns AM, Pollpeter D, Hadizadeh N, Myong S, Marko JF, Horvath CM. ATP hydrolysis enhances RNA recognition and antiviral signal transduction by the innate immune sensor, laboratory of genetics and physiology 2 (LGP2). J Biol Chem 2012. [PMID: 23184951 DOI: 10.1074/jbc.m112.424416] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Laboratory of genetics and physiology 2 (LGP2) is a member of the RIG-I-like receptor family of cytoplasmic pattern recognition receptors that detect molecular signatures of virus infection and initiate antiviral signal transduction cascades. The ATP hydrolysis activity of LGP2 is essential for antiviral signaling, but it has been unclear how the enzymatic properties of LGP2 regulate its biological response. Quantitative analysis of the dsRNA binding and enzymatic activities of LGP2 revealed high dsRNA-independent ATP hydrolysis activity. Biochemical assays and single-molecule analysis of LGP2 and mutant variants that dissociate basal from dsRNA-stimulated ATP hydrolysis demonstrate that LGP2 utilizes basal ATP hydrolysis to enhance and diversify its RNA recognition capacity, enabling the protein to associate with intrinsically poor substrates. This property is required for LGP2 to synergize with another RIG-I-like receptor, MDA5, to potentiate IFNβ transcription in vivo during infection with encephalomyocarditis virus or transfection with poly(I:C). These results demonstrate previously unrecognized properties of LGP2 ATP hydrolysis and RNA interaction and provide a mechanistic basis for a positive regulatory role for LGP2 in antiviral signaling.
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Affiliation(s)
- Annie M Bruns
- Department of Molecular Biosciences, Physics and Astronomy, Northwestern University, Evanston,Illinois 60208, USA
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40
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The variable N-terminal region of DDX5 contains structural elements and auto-inhibits its interaction with NS5B of hepatitis C virus. Biochem J 2012; 446:37-46. [PMID: 22640416 DOI: 10.1042/bj20120001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
RNA helicases of the DEAD (Asp-Glu-Ala-Asp)-box family of proteins are involved in many aspects of RNA metabolism from transcription to RNA decay, but most of them have also been shown to be multifunctional. The DEAD-box helicase DDX5 of host cells has been shown to interact with the RNA-dependent RNA polymerase (NS5B) of HCV (hepatitis C virus). In the present study, we report the presence of two independent NS5B-binding sites in DDX5, one located at the N-terminus and another at the C-terminus. The N-terminal fragment of DDX5, which consists of the first 305 amino acids and shall be referred as DDX5-N, was expressed and crystallized. The crystal structure shows that domain 1 (residues 79-303) of DDX5 contains the typical features found in the structures of other DEAD-box helicases. DDX5-N also contains the highly variable NTR (N-terminal region) of unknown function and the crystal structure reveals structural elements in part of the NTR, namely residues 52-78. This region forms an extensive loop and an α-helix. From co-immunoprecipitation experiments, the NTR of DDX5-N was observed to auto-inhibit its interaction with NS5B. Interestingly, the α-helix in NTR is essential for this auto-inhibition and seems to mediate the interaction between the highly flexible 1-51 residues in NTR and the NS5B-binding site in DDX5-N. Furthermore, NMR investigations reveal that there is a direct interaction between DDX5 and NS5B in vitro.
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41
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Russell R, Jarmoskaite I, Lambowitz AM. Toward a molecular understanding of RNA remodeling by DEAD-box proteins. RNA Biol 2012; 10:44-55. [PMID: 22995827 PMCID: PMC3590237 DOI: 10.4161/rna.22210] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
DEAD-box proteins are superfamily 2 helicases that function in all aspects of RNA metabolism. They employ ATP binding and hydrolysis to generate tight, yet regulated RNA binding, which is used to unwind short RNA helices non-processively and promote structural transitions of RNA and RNA-protein substrates. In the last few years, substantial progress has been made toward a detailed, quantitative understanding of the structural and biochemical properties of DEAD-box proteins. Concurrently, progress has been made toward a physical understanding of the RNA rearrangements and folding steps that are accelerated by DEAD-box proteins in model systems. Here, we review the recent progress on both of these fronts, focusing on the mitochondrial DEAD-box proteins Mss116 and CYT-19 and their mechanisms in promoting the splicing of group I and group II introns.
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Affiliation(s)
- Rick Russell
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX, USA.
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Jarmoskaite I, Russell R. DEAD-box proteins as RNA helicases and chaperones. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 2:135-52. [PMID: 21297876 DOI: 10.1002/wrna.50] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DEAD-box proteins are ubiquitous in RNA-mediated processes and function by coupling cycles of ATP binding and hydrolysis to changes in affinity for single-stranded RNA. Many DEAD-box proteins use this basic mechanism as the foundation for a version of RNA helicase activity, efficiently separating the strands of short RNA duplexes in a process that involves little or no translocation. This activity, coupled with mechanisms to direct different DEAD-box proteins to their physiological substrates, allows them to promote RNA folding steps and rearrangements and to accelerate remodeling of RNA–protein complexes. This review will describe the properties of DEAD-box proteins as RNA helicases and the current understanding of how the energy from ATPase activity is used to drive the separation of RNA duplex strands. It will then describe how the basic biochemical properties allow some DEAD-box proteins to function as chaperones by promoting RNA folding reactions, with a focus on the self-splicing group I and group II intron RNAs.
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Affiliation(s)
- Inga Jarmoskaite
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX, USA
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Cruz-Migoni A, Hautbergue GM, Artymiuk PJ, Baker PJ, Bokori-Brown M, Chang CT, Dickman MJ, Essex-Lopresti A, Harding SV, Mahadi NM, Marshall LE, Mobbs GW, Mohamed R, Nathan S, Ngugi SA, Ong C, Ooi WF, Partridge LJ, Phillips HL, Raih MF, Ruzheinikov S, Sarkar-Tyson M, Sedelnikova SE, Smither SJ, Tan P, Titball RW, Wilson SA, Rice DW. A Burkholderia pseudomallei toxin inhibits helicase activity of translation factor eIF4A. Science 2011; 334:821-4. [PMID: 22076380 DOI: 10.1126/science.1211915] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The structure of BPSL1549, a protein of unknown function from Burkholderia pseudomallei, reveals a similarity to Escherichia coli cytotoxic necrotizing factor 1. We found that BPSL1549 acted as a potent cytotoxin against eukaryotic cells and was lethal when administered to mice. Expression levels of bpsl1549 correlate with conditions expected to promote or suppress pathogenicity. BPSL1549 promotes deamidation of glutamine-339 of the translation initiation factor eIF4A, abolishing its helicase activity and inhibiting translation. We propose to name BPSL1549 Burkholderia lethal factor 1.
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Affiliation(s)
- Abimael Cruz-Migoni
- Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK
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Tuteja R, Mehta J. A genomic glance at the components of the mRNA export machinery in Plasmodium falciparum. Commun Integr Biol 2011; 3:318-26. [PMID: 20798816 DOI: 10.4161/cib.3.4.11886] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 01/29/2023] Open
Abstract
Nuclear export of mRNAs is one of the steps critically important for gene expression and different steps of mRNA processing are linked to the export of the mRNA out of the nucleus. This coupling probably provides a quality control mechanism as well as a higher efficiency for the synthesis of mRNAs. The mRNA is synthesized in the nucleus and then exported to the cytoplasm through the nuclear pore complexes (NPCs), which are embedded in the nuclear envelope. The Mex67-Mtr2 complex in yeast and its counterpart Tap-p15 in higher eukaryotes function as an mRNA exporter through the NPC. Some of the DEAD box proteins such as UAP56 and Dbp5 have been implicated in mRNA export also. In this report using the bioinformatics approach we have analyzed the components of the mRNA export machinery in Plasmodium falciparum and also highlighted the salient features of some of the components. Further detailed studies on various components of nuclear mRNA export in Plasmodium falciparum will be essential to understand this important pathway.
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Affiliation(s)
- Renu Tuteja
- Malaria Group; International Centre for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg, New Delhi India
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Gómez-González B, García-Rubio M, Bermejo R, Gaillard H, Shirahige K, Marín A, Foiani M, Aguilera A. Genome-wide function of THO/TREX in active genes prevents R-loop-dependent replication obstacles. EMBO J 2011; 30:3106-19. [PMID: 21701562 DOI: 10.1038/emboj.2011.206] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 05/25/2011] [Indexed: 11/09/2022] Open
Abstract
THO/TREX is a conserved nuclear complex that functions in mRNP biogenesis and prevents transcription-associated recombination. Whether or not it has a ubiquitous role in the genome is unknown. Chromatin immunoprecipitation (ChIP)-chip studies reveal that the Hpr1 component of THO and the Sub2 RNA-dependent ATPase have genome-wide distributions at active ORFs in yeast. In contrast to RNA polymerase II, evenly distributed from promoter to termination regions, THO and Sub2 are absent at promoters and distributed in a gradual 5' → 3' gradient. This is accompanied by a genome-wide impact of THO-Sub2 deletions on expression of highly expressed, long and high G+C-content genes. Importantly, ChIP-chips reveal an over-recruitment of Rrm3 in active genes in THO mutants that is reduced by RNaseH1 overexpression. Our work establishes a genome-wide function for THO-Sub2 in transcription elongation and mRNP biogenesis that function to prevent the accumulation of transcription-mediated replication obstacles, including R-loops.
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Affiliation(s)
- Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC, Sevilla, Spain
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Strohmeier J, Hertel I, Diederichsen U, Rudolph MG, Klostermeier D. Changing nucleotide specificity of the DEAD-box helicase Hera abrogates communication between the Q-motif and the P-loop. Biol Chem 2011; 392:357-69. [PMID: 21391900 DOI: 10.1515/bc.2011.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
DEAD-box proteins disrupt or remodel RNA and protein/RNA complexes at the expense of ATP. The catalytic core is composed of two flexibly connected RecA-like domains. The N-terminal domain contains most of the motifs involved in nucleotide binding and serves as a minimalistic model for helicase/nucleotide interactions. A single conserved glutamine in the so-called Q-motif has been suggested as a conformational sensor for the nucleotide state. To reprogram the Thermus thermophilus RNA helicase Hera for use of oxo-ATP instead of ATP and to investigate the sensor function of the Q-motif, we analyzed helicase activity of Hera Q28E. Crystal structures of the Hera N-terminal domain Q28E mutant (TthDEAD_Q28E) in apo- and ligand-bound forms show that Q28E does change specificity from adenine to 8-oxoadenine. However, significant structural changes accompany the Q28E mutation, which prevent the P-loop from adopting its catalytically active conformation and explain the lack of helicase activity of Hera_Q28E with either ATP or 8-oxo-ATP as energy sources. 8-Oxo-adenosine, 8-oxo-AMP, and 8-oxo-ADP weakly bind to TthDEAD_Q28E but in non-canonical modes. These results indicate that the Q-motif not only senses the nucleotide state of the helicase but could also stabilize a catalytically competent conformation of the P-loop and other helicase signature motifs.
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Affiliation(s)
- Julian Strohmeier
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
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Serpeloni M, Moraes CB, Muniz JRC, Motta MCM, Ramos ASP, Kessler RL, Inoue AH, Duarte daRocha W, Yamada-Ogatta SF, Fragoso SP, Goldenberg S, Freitas-Junior LH, Ávila AR. An essential nuclear protein in trypanosomes is a component of mRNA transcription/export pathway. PLoS One 2011; 6:e20730. [PMID: 21687672 PMCID: PMC3110772 DOI: 10.1371/journal.pone.0020730] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 05/11/2011] [Indexed: 11/18/2022] Open
Abstract
In eukaryotic cells, different RNA species are exported from the nucleus via specialized pathways. The mRNA export machinery is highly integrated with mRNA processing, and includes a different set of nuclear transport adaptors as well as other mRNA binding proteins, RNA helicases, and NPC-associated proteins. The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease, a widespread and neglected human disease which is endemic to Latin America. Gene expression in Trypanosoma has unique characteristics, such as constitutive polycistronic transcription of protein-encoding genes and mRNA processing by trans-splicing. In general, post-transcriptional events are the major points for regulation of gene expression in these parasites. However, the export pathway of mRNA from the nucleus is poorly understood. The present study investigated the function of TcSub2, which is a highly conserved protein ortholog to Sub2/ UAP56, a component of the Transcription/Export (TREX) multiprotein complex connecting transcription with mRNA export in yeast/human. Similar to its orthologs, TcSub2 is a nuclear protein, localized in dispersed foci all over the nuclei —except the fibrillar center of nucleolus— and at the interface between dense and non-dense chromatin areas, proposing the association of TcSub2 with transcription/processing sites. These findings were analyzed further by BrUTP incorporation assays and confirmed that TcSub2 is physically associated with active RNA polymerase II (RNA pol II), but not RNA polymerase I (RNA pol I) or Spliced Leader (SL) transcription, demonstrating participation particularly in nuclear mRNA metabolism in T. cruzi. The double knockout of the TcSub2 gene is lethal in T. cruzi, suggesting it has an essential function. Alternatively, RNA interference assays were performed in Trypanosoma brucei. It allowed demonstrating that besides being an essential protein, its knockdown causes mRNA accumulation in the nucleus and decrease of translation levels, reinforcing that Trypanosoma-Sub2 (Tryp-Sub2) is a component of mRNA transcription/export pathway in trypanosomes.
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Affiliation(s)
- Mariana Serpeloni
- Departamento de Biologia Celular e Molecular, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
- Laboratório de Regulação da Expressão gênica, Instituto Carlos Chagas (ICC), Curitiba, Brazil
| | - Carolina Borsoi Moraes
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea (IPK), Gyeonggi-do, South Korea
| | | | - Maria Cristina Machado Motta
- Departamento de Biologia Celular e Parasitologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | | | - Rafael Luis Kessler
- Departamento de Biologia Celular e Molecular, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
- Laboratório de Regulação da Expressão gênica, Instituto Carlos Chagas (ICC), Curitiba, Brazil
| | - Alexandre Haruo Inoue
- Departamento de Biologia Celular e Molecular, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
- Laboratório de Regulação da Expressão gênica, Instituto Carlos Chagas (ICC), Curitiba, Brazil
| | | | - Sueli Fumie Yamada-Ogatta
- Departamento de Microbiologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina (UEL), Londrina, Brazil
| | - Stenio Perdigão Fragoso
- Laboratório de Regulação da Expressão gênica, Instituto Carlos Chagas (ICC), Curitiba, Brazil
| | - Samuel Goldenberg
- Laboratório de Regulação da Expressão gênica, Instituto Carlos Chagas (ICC), Curitiba, Brazil
| | - Lucio H. Freitas-Junior
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea (IPK), Gyeonggi-do, South Korea
| | - Andréa Rodrigues Ávila
- Laboratório de Regulação da Expressão gênica, Instituto Carlos Chagas (ICC), Curitiba, Brazil
- * E-mail:
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Dutta A, Zheng S, Jain D, Cameron CE, Reese JC. Intermolecular interactions within the abundant DEAD-box protein Dhh1 regulate its activity in vivo. J Biol Chem 2011; 286:27454-70. [PMID: 21642421 DOI: 10.1074/jbc.m111.220251] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Dhh1 is a highly conserved DEAD-box protein that has been implicated in many processes involved in mRNA regulation. At least some functions of Dhh1 may be carried out in cytoplasmic foci called processing bodies (P-bodies). Dhh1 was identified initially as a putative RNA helicase based solely on the presence of conserved helicase motifs found in the superfamily 2 (Sf2) of DEXD/H-box proteins. Although initial mutagenesis studies revealed that the signature DEAD-box motif is required for Dhh1 function in vivo, enzymatic (ATPase or helicase) or ATP binding activities of Dhh1 or those of any its many higher eukaryotic orthologues have not been described. Here we provide the first characterization of the biochemical activities of Dhh1. Dhh1 has weaker RNA-dependent ATPase activity than other well characterized DEAD-box helicases. We provide evidence that intermolecular interactions between the N- and C-terminal RecA-like helicase domains restrict its ATPase activity; mutation of residues mediating these interactions enhanced ATP hydrolysis. Interestingly, the interdomain interaction mutant displayed enhanced mRNA turnover, RNA binding, and recruitment into cytoplasmic foci in vivo compared with wild type Dhh1. Also, we demonstrate that the ATPase activity of Dhh1 is not required for it to be recruited into cytoplasmic foci, but it regulates its association with RNA in vivo. We hypothesize that the activity of Dhh1 is restricted by interdomain interactions, which can be regulated by cellular factors to impart stringent control over this very abundant RNA helicase.
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Affiliation(s)
- Arnob Dutta
- Center for Eukaryotic Gene Regulation, Penn State University, University Park, Pennsylvania 16802, USA
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Brinkmeyer-Langford CL, Murphy WJ, Childers CP, Skow LC. A conserved segmental duplication within ELA. Anim Genet 2010; 41 Suppl 2:186-95. [DOI: 10.1111/j.1365-2052.2010.02137.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chang TC, Liu WS. The molecular evolution of PL10 homologs. BMC Evol Biol 2010; 10:127. [PMID: 20438638 PMCID: PMC2874800 DOI: 10.1186/1471-2148-10-127] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 05/03/2010] [Indexed: 12/12/2022] Open
Abstract
Background PL10 homologs exist in a wide range of eukaryotes from yeast, plants to animals. They share a DEAD motif and belong to the DEAD-box polypeptide 3 (DDX3) subfamily with a major role in RNA metabolism. The lineage-specific expression patterns and various genomic structures and locations of PL10 homologs indicate these homologs have an interesting evolutionary history. Results Phylogenetic analyses revealed that, in addition to the sex chromosome-linked PL10 homologs, DDX3X and DDX3Y, a single autosomal PL10 putative homologous sequence is present in each genome of the studied non-rodent eutheria. These autosomal homologous sequences originated from the retroposition of DDX3X but were pseudogenized during the evolution. In rodents, besides Ddx3x and Ddx3y, we found not only Pl10 but another autosomal homologous region, both of which also originated from the Ddx3x retroposition. These retropositions occurred after the divergence of eutheria and opossum. In contrast, an additional X putative homologous sequence was detected in primates and originated from the transposition of DDX3Y. The evolution of PL10 homologs was under positive selection and the elevated Ka/Ks ratios were observed in the eutherian lineages for DDX3Y but not PL10 and DDX3X, suggesting relaxed selective constraints on DDX3Y. Contrary to the highly conserved domains, several sites with relaxed selective constraints flanking the domains in the mammalian PL10 homologs may play roles in enhancing the gene function in a lineage-specific manner. Conclusion The eutherian DDX3X/DDX3Y in the X/Y-added region originated from the translocation of the ancient PL10 ortholog on the ancestral autosome, whereas the eutherian PL10 was retroposed from DDX3X. In addition to the functional PL10/DDX3X/DDX3Y, conserved homologous regions on the autosomes and X chromosome are present. The autosomal homologs were also derived from DDX3X, whereas the additional X-homologs were derived from DDX3Y. These homologs were apparently pseudogenized but may still be active transcriptionally. The evolution of PL10 homologs was positively selected.
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Affiliation(s)
- Ti-Cheng Chang
- Department of Dairy and Animal Science, The Center for Reproductive Biology and Health (CRBH), College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
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