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Deutzmann A, Sullivan DK, Dhanasekaran R, Li W, Chen X, Tong L, Mahauad-Fernandez WD, Bell J, Mosley A, Koehler AN, Li Y, Felsher DW. Nuclear to cytoplasmic transport is a druggable dependency in MYC-driven hepatocellular carcinoma. Nat Commun 2024; 15:963. [PMID: 38302473 PMCID: PMC10834515 DOI: 10.1038/s41467-024-45128-y] [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: 08/20/2019] [Accepted: 01/12/2024] [Indexed: 02/03/2024] Open
Abstract
The MYC oncogene is often dysregulated in human cancer, including hepatocellular carcinoma (HCC). MYC is considered undruggable to date. Here, we comprehensively identify genes essential for survival of MYChigh but not MYClow cells by a CRISPR/Cas9 genome-wide screen in a MYC-conditional HCC model. Our screen uncovers novel MYC synthetic lethal (MYC-SL) interactions and identifies most MYC-SL genes described previously. In particular, the screen reveals nucleocytoplasmic transport to be a MYC-SL interaction. We show that the majority of MYC-SL nucleocytoplasmic transport genes are upregulated in MYChigh murine HCC and are associated with poor survival in HCC patients. Inhibiting Exportin-1 (XPO1) in vivo induces marked tumor regression in an autochthonous MYC-transgenic HCC model and inhibits tumor growth in HCC patient-derived xenografts. XPO1 expression is associated with poor prognosis only in HCC patients with high MYC activity. We infer that MYC may generally regulate and require altered expression of nucleocytoplasmic transport genes for tumorigenesis.
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Affiliation(s)
- Anja Deutzmann
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Delaney K Sullivan
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Renumathy Dhanasekaran
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
- Division of Gastroenterology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Wei Li
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, 20012, USA
- Department of Genomics and Precision Medicine, George Washington University, Washington, DC, 20012, USA
| | - Xinyu Chen
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Ling Tong
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
| | | | - John Bell
- Stanford Genome Technology Center, Stanford University, Stanford, CA, 94305, USA
| | - Adriane Mosley
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Angela N Koehler
- Koch Institute for Integrative Cancer Research at MIT, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Center for Precision Cancer Medicine, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Yulin Li
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA.
- Institute for Academic Medicine, Houston Methodist and Weill Cornell Medical College, Houston, TX, 77030, USA.
| | - Dean W Felsher
- Division of Oncology, Department of Medicine, Stanford University, Stanford, CA, 94305, USA.
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA.
- Stanford Cancer Institute, Stanford University, Stanford, CA, 94305, USA.
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2
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Ávila AR, Cabezas-Cruz A, Gissot M. mRNA export in the apicomplexan parasite Toxoplasma gondii: emerging divergent components of a crucial pathway. Parasit Vectors 2018; 11:62. [PMID: 29370868 PMCID: PMC5785795 DOI: 10.1186/s13071-018-2648-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/15/2018] [Indexed: 01/08/2023] Open
Abstract
Control of gene expression is crucial for parasite survival and is the result of a series of processes that are regulated to permit fine-tuning of gene expression in response to biological changes during the life-cycle of apicomplexan parasites. Control of mRNA nuclear export is a key process in eukaryotic cells but is poorly understood in apicomplexan parasites. Here, we review recent knowledge regarding this process with an emphasis on T. gondii. We describe the presence of divergent orthologs and discuss structural and functional differences in export factors between apicomplexans and other eukaryotic lineages. Undoubtedly, the use of the CRISPR/Cas9 system in high throughput screenings associated with the discovery of mRNA nuclear export complexes by proteomic analysis will contribute to identify these divergent factors. Ligand-based or structure-based strategies may be applied to investigate the potential use of these proteins as targets for new antiprotozoal agents.
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Affiliation(s)
- Andréa Rodrigues Ávila
- Instituto Carlos Chagas, FIOCRUZ, Rua Algacyr Munhoz Mader, 3775. CIC, Curitiba, PR, 81350-010, Brazil. .,UMR BIPAR, Animal Health Laboratory, ANSES, INRA, ENVA, Maisons Alfort, Cedex, France.
| | - Alexjandro Cabezas-Cruz
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, ENVA, Maisons Alfort, Cedex, France.,Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Mathieu Gissot
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Centre d'Infection et d'Immunité de Lille, F-59000, Lille, France.
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3
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Hauk G, Bowman GD. Formation of a Trimeric Xpo1-Ran[GTP]-Ded1 Exportin Complex Modulates ATPase and Helicase Activities of Ded1. PLoS One 2015; 10:e0131690. [PMID: 26120835 PMCID: PMC4484809 DOI: 10.1371/journal.pone.0131690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/05/2015] [Indexed: 11/24/2022] Open
Abstract
The DEAD-box RNA helicase Ded1, which is essential in yeast and known as DDX3 in humans, shuttles between the nucleus and cytoplasm and takes part in several basic processes including RNA processing and translation. A key interacting partner of Ded1 is the exportin Xpo1, which together with the GTP-bound state of the small GTPase Ran, facilitates unidirectional transport of Ded1 out of the nucleus. Here we demonstrate that Xpo1 and Ran[GTP] together reduce the RNA-stimulated ATPase and helicase activities of Ded1. Binding and inhibition of Ded1 by Xpo1 depend on the affinity of the Ded1 nuclear export sequence (NES) for Xpo1 and the presence of Ran[GTP]. Association with Xpo1/Ran[GTP] reduces RNA-stimulated ATPase activity of Ded1 by increasing the apparent KM for the RNA substrate. Despite the increased KM, the Ded1:Xpo1:Ran[GTP] ternary complex retains the ability to bind single stranded RNA, suggesting that Xpo1/Ran[GTP] may modulate the substrate specificity of Ded1. These results demonstrate that, in addition to transport, exportins such as Xpo1 also have the capability to alter enzymatic activities of their cargo.
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Affiliation(s)
- Glenn Hauk
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Gregory D. Bowman
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America
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4
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Cautain B, Hill R, de Pedro N, Link W. Components and regulation of nuclear transport processes. FEBS J 2014; 282:445-62. [PMID: 25429850 PMCID: PMC7163960 DOI: 10.1111/febs.13163] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/11/2014] [Accepted: 11/12/2014] [Indexed: 12/27/2022]
Abstract
The spatial separation of DNA replication and gene transcription in the nucleus and protein translation in the cytoplasm is a uniform principle of eukaryotic cells. This compartmentalization imposes a requirement for a transport network of macromolecules to shuttle these components in and out of the nucleus. This nucleo‐cytoplasmic transport of macromolecules is critical for both cell physiology and pathology. Consequently, investigating its regulation and disease‐associated alterations can reveal novel therapeutic approaches to fight human diseases, such as cancer or viral infection. The characterization of the nuclear pore complex, the identification of transport signals and transport receptors, as well as the characterization of the Ran system (providing the energy source for efficient cargo transport) has greatly facilitated our understanding of the components, mechanisms and regulation of the nucleo‐cytoplasmic transport of proteins in our cells. Here we review this knowledge with a specific emphasis on the selection of disease‐relevant molecular targets for potential therapeutic intervention.
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Affiliation(s)
- Bastien Cautain
- Fundacion MEDINA Parque tecnológico ciencias de la salud, Granada, Spain
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Köhn M, Pazaitis N, Hüttelmaier S. Why YRNAs? About Versatile RNAs and Their Functions. Biomolecules 2013; 3:143-56. [PMID: 24970161 PMCID: PMC4030889 DOI: 10.3390/biom3010143] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 01/27/2013] [Accepted: 01/31/2013] [Indexed: 11/20/2022] Open
Abstract
Y RNAs constitute a family of highly conserved small noncoding RNAs (in humans: 83-112 nt; Y1, Y3, Y4 and Y5). They are transcribed from individual genes by RNA-polymerase III and fold into conserved stem-loop-structures. Although discovered 30 years ago, insights into the cellular and physiological role of Y RNAs remains incomplete. In this review, we will discuss knowledge on the structural properties, associated proteins and discuss proposed functions of Y RNAs. We suggest Y RNAs to be an integral part of ribonucleoprotein networks within cells and could therefore have substantial influence on many different cellular processes. Putative functions of Y RNAs include small RNA quality control, DNA replication, regulation of the cellular stress response and proliferation. This suggests Y RNAs as essential regulators of cell fate and indicates future avenues of research, which will provide novel insights into the role of small noncoding RNAs in gene expression.
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Affiliation(s)
- Marcel Köhn
- Martin-Luther-University Halle-Wittenberg, Institute of Molecular Medicine, Section Molecular Cell Biology, ZAMED, Heinrich-Damerow-Str.1, D-6120 Halle, Germany.
| | - Nikolaos Pazaitis
- Martin-Luther-University Halle-Wittenberg, Institute of Molecular Medicine, Section Molecular Cell Biology, ZAMED, Heinrich-Damerow-Str.1, D-6120 Halle, Germany.
| | - Stefan Hüttelmaier
- Martin-Luther-University Halle-Wittenberg, Institute of Molecular Medicine, Section Molecular Cell Biology, ZAMED, Heinrich-Damerow-Str.1, D-6120 Halle, Germany.
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Xu D, Grishin NV, Chook YM. NESdb: a database of NES-containing CRM1 cargoes. Mol Biol Cell 2012; 23:3673-6. [PMID: 22833564 PMCID: PMC3442414 DOI: 10.1091/mbc.e12-01-0045] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/16/2012] [Accepted: 07/16/2012] [Indexed: 12/27/2022] Open
Abstract
The leucine-rich nuclear export signal (NES) is the only known class of targeting signal that directs macromolecules out of the cell nucleus. NESs are short stretches of 8-15 amino acids with regularly spaced hydrophobic residues that bind the export karyopherin CRM1. NES-containing proteins are involved in numerous cellular and disease processes. We compiled a database named NESdb that contains 221 NES-containing CRM1 cargoes that were manually curated from the published literature. Each NESdb entry is annotated with information about sequence and structure of both the NES and the cargo protein, as well as information about experimental evidence of NES-mapping and CRM1-mediated nuclear export. NESdb will be updated regularly and will serve as an important resource for nuclear export signals. NESdb is freely available to nonprofit organizations at http://prodata.swmed.edu/LRNes.
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Affiliation(s)
- Darui Xu
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Nick V. Grishin
- Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
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7
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Host- and strain-specific regulation of influenza virus polymerase activity by interacting cellular proteins. mBio 2011; 2:mBio.00151-11. [PMID: 21846828 PMCID: PMC3157893 DOI: 10.1128/mbio.00151-11] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Highly pathogenic avian influenza A (HPAI) viruses of the H5N1 subtype have recently emerged from avian zoonotic reservoirs to cause fatal human disease. Adaptation of HPAI virus RNA-dependent RNA polymerase (PB1, PB2, and PA proteins) and nucleoprotein (NP) to interactions with mammalian host proteins is thought to contribute to the efficiency of viral RNA synthesis and to disease severity. While proteomics experiments have identified a number of human proteins that associate with H1N1 polymerases and/or viral ribonucleoprotein (vRNP), how these host interactions might regulate influenza virus polymerase functions and host adaptation has been largely unexplored. We took a functional genomics (RNA interference [RNAi]) approach to assess the roles of a network of human proteins interacting with influenza virus polymerase proteins in viral polymerase activity from prototype H1N1 and H5N1 viruses. A majority (18 of 31) of the cellular proteins tested, including RNA-binding (DDX17, DDX5, NPM1, and hnRNPM), stress (PARP1, DDB1, and Ku70/86), and intracellular transport proteins, were required for efficient activity of both H1N1 and H5N1 polymerases. NXP2 and NF90 antagonized both polymerases, and six more RNA-associated proteins exhibited strain-specific phenotypes. Remarkably, 12 proteins differentially regulated H5N1 polymerase according to PB2 genotype at mammalian-adaptive residue 627. Among these, DEAD box RNA helicase DDX17/p72 facilitated efficient human-adapted (627K) H5N1 virus mRNA and viral RNA (vRNA) synthesis in human cells. Likewise, the chicken DDX17 homologue was required for efficient avian (627E) H5N1 infection in chicken DF-1 fibroblasts, suggesting that this conserved virus-host interaction contributes to PB2-dependent host species specificity of influenza virus and ultimately to the outcome of human HPAI infections. Highly pathogenic avian influenza A (HPAI) viruses have recently emerged from wild and domestic birds to cause fatal human disease. In human patients, it is thought that adaptation of the viral polymerase, a complex of viral proteins responsible for viral gene expression and RNA genome replication, to interactions with mammalian rather than avian host proteins contributes to disease severity. In this study, we used computational analysis and RNA interference (RNAi) experiments to identify a biological network of human proteins that regulates an H5N1 HPAI virus polymerase, in comparison to a mammalian H1N1 virus. Of 31 proteins tested, 18 (58%) were required for polymerase function in both HPAI and H1N1 viruses. Remarkably, we also found proteins such as DDX17 that governed the HPAI virus polymerase’s adaptation to human cells. These virus-host interactions may thus control pathogenicity of HPAI virus in humans and are promising therapeutic targets for antiviral drugs in severe influenza infections.
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8
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Abstract
Green fluorescent protein (GFP) and its derivatives have transformed the use and analysis of proteins for diverse applications. Like proteins, RNA has complex roles in cellular function and is increasingly used for various applications, but a comparable approach for fluorescently tagging RNA is lacking. Here, we describe the generation of RNA aptamers that bind fluorophores resembling the fluorophore in GFP. These RNA-fluorophore complexes create a palette that spans the visible spectrum. An RNA-fluorophore complex, termed Spinach, resembles enhanced GFP and emits a green fluorescence comparable in brightness with fluorescent proteins. Spinach is markedly resistant to photobleaching, and Spinach fusion RNAs can be imaged in living cells. These RNA mimics of GFP provide an approach for genetic encoding of fluorescent RNAs.
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Affiliation(s)
- Jeremy S Paige
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY 10065, USA
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9
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Hutten S, Kehlenbach RH. CRM1-mediated nuclear export: to the pore and beyond. Trends Cell Biol 2007; 17:193-201. [PMID: 17317185 DOI: 10.1016/j.tcb.2007.02.003] [Citation(s) in RCA: 292] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 01/11/2007] [Accepted: 02/09/2007] [Indexed: 02/07/2023]
Abstract
CRM1 (chromosome region maintenance 1; also referred to as exportin1 or Xpo1) is a member of the importin beta superfamily of nuclear transport receptors, recognizing proteins bearing a leucine-rich nuclear export sequence. CRM1 is the major receptor for the export of proteins out of the nucleus and is also required for transport of many RNAs. Besides its established role in nuclear export, CRM1 is also implicated in various steps during mitosis, widening its functional spectrum within the cell.
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Affiliation(s)
- Saskia Hutten
- Universität Göttingen; Zentrum für Biochemie und Molekulare Zellbiologie; Humboldtallee 23; 37073 Göttingen, Germany
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10
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Zhao J, Jin SB, Wieslander L. CRM1 and Ran are present but a NES-CRM1-RanGTP complex is not required in Balbiani ring mRNP particles from the gene to the cytoplasm. J Cell Sci 2004; 117:1553-66. [PMID: 15020682 DOI: 10.1242/jcs.00992] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Messenger RNA is formed from precursors known as pre-mRNA. These precursors associate with proteins to form pre-mRNA-protein (pre-mRNP) complexes. Processing machines cap, splice and polyadenylate the pre-mRNP and in this way build the mRNP. These processing machines also affect the export of the mRNP complexes from the nucleus to the cytoplasm. Export to the cytoplasm takes place through a structure in the nuclear membrane called the nuclear pore complex (NPC). Export involves adapter proteins in the mRNP and receptor proteins that bind to the adapter proteins and to components of the NPC. We show that the export receptor chromosomal region maintenance protein 1 (CRM1), belonging to a family of proteins known as importin-beta-like proteins, binds to gene-specific Balbiani ring (BR) pre-mRNP while transcription takes place. We also show that the GTPase known as Ran binds to BR pre-mRNP, and that it binds mainly in the interchromatin. However, we also show using leptomycin B treatment that a NES-CRM1-RanGTP complex is not essential for export, even though both CRM1 and Ran accompany the BR mRNP through the NPC. Our results therefore suggest that several export receptors associate with BR mRNP and that these receptors have redundant functions in the nuclear export of BR mRNP.
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Affiliation(s)
- Jian Zhao
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden
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Alavian CN, Politz JCR, Lewandowski LB, Powers CM, Pederson T. Nuclear export of signal recognition particle RNA in mammalian cells. Biochem Biophys Res Commun 2004; 313:351-5. [PMID: 14684167 DOI: 10.1016/j.bbrc.2003.11.126] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In mammalian cells the signal recognition particle (SRP) consists of a approximately 300 nucleotide RNA and six proteins. Although the molecular structure and functional cycle of the SRP are both very well understood, far less is known about how the SRP is first assembled in the cell. Recent work has suggested that SRP assembly begins in the nucleoli. When NRK (rat fibroblast) cells were treated with leptomycin B (LMB), a specific inhibitor of the CRM1 nuclear export receptor, the level of SRP RNA increased in the nucleoli, as did the level of nucleolar 28S ribosomal RNA. Moreover, when a hamster cell line carrying a temperature-sensitive mutation in the guanine nucleotide exchange factor of the GTPase Ran (Ran-GEF) was shifted to the non-permissive temperature, the nucleolar level of SRP RNA increased. These results indicate that the steady-state concentration of SRP RNA in the nucleolus is sensitive to perturbations in nuclear import/export pathways.
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Affiliation(s)
- Christina N Alavian
- Department of Biochemistry and Molecular Pharmacology and Program in Cell Dynamics, University of Massachusetts Medical School, Worcester, MA 01605, USA
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12
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Abstract
A library of random mutations in Xenopus ribosomal protein L5 was generated by error-prone PCR and used to delineate the binding domain for 5S rRNA. All but one of the amino acid substitutions that affected binding affinity are clustered in the central region of the protein. Several of the mutations are conservative substitutions of non-polar amino acid residues that are unlikely to form energetically significant contacts to the RNA. Thermal denaturation, monitored by circular dichroism (CD), indicates that L5 is not fully structured and association with 5S rRNA increases the t(m) of the protein by 16 degrees C. L5 induces changes in the CD spectrum of 5S rRNA, establishing that the complex forms by a mutual induced fit mechanism. Deuterium exchange reveals that a considerable amount of L5 is unstructured in the absence of 5S rRNA. The fluorescence emission of W266 provides evidence for structural changes in the C-terminal region of L5 upon binding to 5S rRNA; whereas, protection experiments demonstrate that the N terminus remains highly sensitive to protease digestion in the complex. Analysis of the amino acid sequence of L5 by the program PONDR predicts that the N and C-terminal regions of L5 are intrinsically disordered, but that the central region, which contains three essential tyrosine residues and other residues important for binding to 5S rRNA, is likely to be structured. Initial interaction of the protein with 5S rRNA likely occurs through this region, followed by induced folding of the C-terminal region. The persistent disorder in the N-terminal domain is possibly exploited for interactions between the L5-5S rRNA complex and other proteins.
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Affiliation(s)
- Jonathan P DiNitto
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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