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Hao X, Gong Y, Chen S, Ma C, Duanmu H. Genome-Wide Identification of GRAS Transcription Factors and Their Functional Analysis in Salt Stress Response in Sugar Beet. Int J Mol Sci 2024; 25:7132. [PMID: 39000240 PMCID: PMC11241673 DOI: 10.3390/ijms25137132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/08/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024] Open
Abstract
GAI-RGA-and-SCR (GRAS) transcription factors can regulate many biological processes such as plant growth and development and stress defense, but there are few related studies in sugar beet. Salt stress can seriously affect the yield and quality of sugar beet (Beta vulgaris). Therefore, this study used bioinformatics methods to identify GRAS transcription factors in sugar beet and analyzed their structural characteristics, evolutionary relationships, regulatory networks and salt stress response patterns. A total of 28 BvGRAS genes were identified in the whole genome of sugar beet, and the sequence composition was relatively conservative. According to the topology of the phylogenetic tree, BvGRAS can be divided into nine subfamilies: LISCL, SHR, PAT1, SCR, SCL3, LAS, SCL4/7, HAM and DELLA. Synteny analysis showed that there were two pairs of fragment replication genes in the BvGRAS gene, indicating that gene replication was not the main source of BvGRAS family members. Regulatory network analysis showed that BvGRAS could participate in the regulation of protein interaction, material transport, redox balance, ion homeostasis, osmotic substance accumulation and plant morphological structure to affect the tolerance of sugar beet to salt stress. Under salt stress, BvGRAS and its target genes showed an up-regulated expression trend. Among them, BvGRAS-15, BvGRAS-19, BvGRAS-20, BvGRAS-21, LOC104892636 and LOC104893770 may be the key genes for sugar beet's salt stress response. In this study, the structural characteristics and biological functions of BvGRAS transcription factors were analyzed, which provided data for the further study of the molecular mechanisms of salt stress and molecular breeding of sugar beet.
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Affiliation(s)
- Xiaolin Hao
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China; (X.H.); (Y.G.); (C.M.)
- Heilongjiang Provincial Key Laboratory of Ecological Restoration and Resource Utilization for Cold Region, School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Yongyong Gong
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China; (X.H.); (Y.G.); (C.M.)
- Heilongjiang Provincial Key Laboratory of Ecological Restoration and Resource Utilization for Cold Region, School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Sixue Chen
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA;
| | - Chunquan Ma
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China; (X.H.); (Y.G.); (C.M.)
- Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Huizi Duanmu
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China; (X.H.); (Y.G.); (C.M.)
- Heilongjiang Provincial Key Laboratory of Ecological Restoration and Resource Utilization for Cold Region, School of Life Sciences, Heilongjiang University, Harbin 150080, China
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2
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Endo N, Tsukimoto R, Isono K, Hosoi A, Yamaguchi R, Tanaka K, Iuchi S, Yotsui I, Sakata Y, Taji T. MOS4-associated complex contributes to proper splicing and suppression of ER stress under long-term heat stress in Arabidopsis. PNAS NEXUS 2023; 2:pgad329. [PMID: 38024402 PMCID: PMC10644990 DOI: 10.1093/pnasnexus/pgad329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023]
Abstract
Plants are often exposed not only to short-term (S-) but also to long-term (L-)heat stress over several consecutive days. A few Arabidopsis mutants defective in L-heat tolerance have been identified, but the molecular mechanisms are less understood for this tolerance than for S-heat stress tolerance. To elucidate the mechanisms of the former, we used a forward genetic screen for sensitive to long-term heat (sloh) mutants and isolated sloh3 and sloh63. The mutants were hypersensitive to L- but not to S-heat stress, and sloh63 was also hypersensitive to salt stress. We identified the causal genes, SLOH3 and SLOH63, both of which encoded splicing-related components of the MOS4-associated complex (MAC). This complex is widely conserved in eukaryotes and has been suggested to interact with spliceosomes. Both genes were induced by L-heat stress in a time-dependent manner, and some abnormal splicing events were observed in both mutants under L-heat stress. In addition, endoplasmic reticulum (ER) stress and subsequent unfolded protein response occurred in both mutants under L-heat stress and were especially prominent in sloh63, suggesting that enhanced ER stress is due to the salt hypersensitivity of sloh63. Splicing inhibitor pladienolide B led to concentration-dependent disturbance of splicing, decreased L-heat tolerance, and enhanced ER stress. These findings suggest that maintenance of precise mRNA splicing under L-heat stress by the MAC is important for L-heat tolerance and suppressing ER stress in Arabidopsis.
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Affiliation(s)
- Naoya Endo
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Ryo Tsukimoto
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Kazuho Isono
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Akito Hosoi
- NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Ryo Yamaguchi
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Keisuke Tanaka
- NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Satoshi Iuchi
- RIKEN BioResource Research Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Izumi Yotsui
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Yoichi Sakata
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Teruaki Taji
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
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3
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Folding and Stability of Ankyrin Repeats Control Biological Protein Function. Biomolecules 2021; 11:biom11060840. [PMID: 34198779 PMCID: PMC8229355 DOI: 10.3390/biom11060840] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 01/04/2023] Open
Abstract
Ankyrin repeat proteins are found in all three kingdoms of life. Fundamentally, these proteins are involved in protein-protein interaction in order to activate or suppress biological processes. The basic architecture of these proteins comprises repeating modules forming elongated structures. Due to the lack of long-range interactions, a graded stability among the repeats is the generic properties of this protein family determining both protein folding and biological function. Protein folding intermediates were frequently found to be key for the biological functions of repeat proteins. In this review, we discuss most recent findings addressing this close relation for ankyrin repeat proteins including DARPins, Notch receptor ankyrin repeat domain, IκBα inhibitor of NFκB, and CDK inhibitor p19INK4d. The role of local folding and unfolding and gradual stability of individual repeats will be discussed during protein folding, protein-protein interactions, and post-translational modifications. The conformational changes of these repeats function as molecular switches for biological regulation, a versatile property for modern drug discovery.
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4
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Sherman EJ, Mitchell DC, Garner AL. The RNA-binding protein SART3 promotes miR-34a biogenesis and G 1 cell cycle arrest in lung cancer cells. J Biol Chem 2019; 294:17188-17196. [PMID: 31619517 PMCID: PMC6873168 DOI: 10.1074/jbc.ac119.010419] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/04/2019] [Indexed: 12/14/2022] Open
Abstract
MicroRNAs (miRNAs or miRs) are small, noncoding RNAs that are implicated in the regulation of most biological processes. Global miRNA biogenesis is altered in many cancers, and RNA-binding proteins play a role in miRNA biogenesis, presenting a promising avenue for targeting miRNA dysregulation in diseases. miR-34a exhibits tumor-suppressive activities by targeting cell cycle regulators CDK4/6 and anti-apoptotic factor BCL-2, among other regulatory pathways such as Wnt, TGF-β, and Notch signaling. Many cancers exhibit down-regulation or loss of miR-34a, and synthetic miR-34a supplementation has been shown to inhibit tumor growth in vivo However, the post-transcriptional mechanisms that cause miR-34a loss in cancer are not entirely understood. Here, using a proteomics-mediated approach in non-small-cell lung cancer (NSCLC) cells, we identified squamous cell carcinoma antigen recognized by T-cells 3 (SART3) as a putative pre-miR-34a-binding protein. SART3 is a spliceosome recycling factor and nuclear RNA-binding protein with no previously reported role in miRNA regulation. We found that SART3 binds pre-miR-34a with higher specificity than pre-let-7d (used as a negative control) and elucidated a new functional role for SART3 in NSCLC cells. SART3 overexpression increased miR-34a levels, down-regulated the miR-34a target genes CDK4/6, and caused a cell cycle arrest in the G1 phase. In vitro binding experiments revealed that the RNA-recognition motifs within the SART3 sequence are responsible for selective pre-miR-34a binding. Our results provide evidence for a significant role of SART3 in miR-34a biogenesis and cell cycle progression in NSCLC cells.
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Affiliation(s)
- Emily J Sherman
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Dylan C Mitchell
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Amanda L Garner
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109
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5
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Abetov DA, Kiyan VS, Zhylkibayev AA, Sarbassova DA, Alybayev SD, Spooner E, Song MS, Bersimbaev RI, Sarbassov DD. Formation of mammalian preribosomes proceeds from intermediate to composed state during ribosome maturation. J Biol Chem 2019; 294:10746-10757. [PMID: 31076509 DOI: 10.1074/jbc.ac119.008378] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/07/2019] [Indexed: 12/28/2022] Open
Abstract
In eukaryotes, ribosome assembly is a rate-limiting step in ribosomal biogenesis that takes place in a distinctive subnuclear organelle, the nucleolus. How ribosomes get assembled at the nucleolar site by forming initial preribosomal complexes remains poorly characterized. In this study, using several human and murine cell lines, we developed a method for isolation of native mammalian preribosomal complexes by lysing cell nuclei through mild sonication. A sucrose gradient fractionation of the nuclear lysate resolved several ribonucleoprotein (RNP) complexes containing rRNAs and ribosomal proteins. Characterization of the RNP complexes with MS-based protein identification and Northern blotting-based rRNA detection approaches identified two types of preribosomes we named here as intermediate preribosomes (IPRibs) and composed preribosome (CPRib). IPRib complexes comprised large preribosomes (105S to 125S in size) containing the rRNA modification factors and premature rRNAs. We further observed that a distinctive CPRib complex consists of an 85S preribosome assembled with mature rRNAs and a ribosomal biogenesis factor, Ly1 antibody-reactive (LYAR), that does not associate with premature rRNAs and rRNA modification factors. rRNA-labeling experiments uncovered that IPRib assembly precedes CPRib complex formation. We also found that formation of the preribosomal complexes is nutrient-dependent because the abundances of IPRib and CPRib decreased substantially when cells were either deprived of amino acids or exposed to an mTOR kinase inhibitor. These findings indicate that preribosomes form via dynamic and nutrient-dependent processing events and progress from an intermediate to a composed state during ribosome maturation.
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Affiliation(s)
- Danysh A Abetov
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Vladimir S Kiyan
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Assylbek A Zhylkibayev
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Dilara A Sarbassova
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Sanzhar D Alybayev
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Eric Spooner
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142
| | - Min Sup Song
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030; MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas 77030
| | - Rakhmetkazhy I Bersimbaev
- Department of Natural Sciences, L. N. Gumilyov Eurasian National University, Nur-Sultan 010000, Kazakhstan, and
| | - Dos D Sarbassov
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030; MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas 77030,; Department of Biology, Nazarbayev University, Nur-Sultan 010000, Kazakhstan.
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6
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Boissier F, Schmidt CM, Linnemann J, Fribourg S, Perez-Fernandez J. Pwp2 mediates UTP-B assembly via two structurally independent domains. Sci Rep 2017; 7:3169. [PMID: 28600509 PMCID: PMC5466602 DOI: 10.1038/s41598-017-03034-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/21/2017] [Indexed: 11/24/2022] Open
Abstract
The SSU processome constitutes a large ribonucleoprotein complex involved in the early steps of ribosome biogenesis. UTP-B is one of the first multi-subunit protein complexes that associates with the pre-ribosomal RNA to form the SSU processome. To understand the molecular basis of the hierarchical assembly of the SSU-processome, we have undergone a structural and functional analysis of the UTP-B subunit Pwp2p. We show that Pwp2p is required for the proper assembly of UTP-B and for a productive association of UTP-B with pre-rRNA. These two functions are mediated by two distinct structural domains. The N-terminal domain of Pwp2p folds into a tandem WD-repeat (tWD) that associates with Utp21p, Utp18p, and Utp6p to form a core complex. The CTDs of Pwp2p and Utp21p mediate the assembly of the heterodimer Utp12p:Utp13p that is required for the stable incorporation of the UTP-B complex in the SSU processome. Finally, we provide evidence suggesting a role of UTP-B as a platform for the binding of assembly factors during the maturation of 20S rRNA precursors.
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Affiliation(s)
- Fanny Boissier
- Université de Bordeaux, INSERM U1212, CNRS 5320, Bordeaux, France
| | - Christina Maria Schmidt
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Lehrstuhl Biochemie III, D-93053, Regensburg, Germany
| | - Jan Linnemann
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Lehrstuhl Biochemie III, D-93053, Regensburg, Germany
| | | | - Jorge Perez-Fernandez
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Lehrstuhl Biochemie III, D-93053, Regensburg, Germany.
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7
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Chaker-Margot M, Barandun J, Hunziker M, Klinge S. Architecture of the yeast small subunit processome. Science 2016; 355:science.aal1880. [PMID: 27980088 DOI: 10.1126/science.aal1880] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/05/2016] [Indexed: 12/21/2022]
Abstract
The small subunit (SSU) processome, a large ribonucleoprotein particle, organizes the assembly of the eukaryotic small ribosomal subunit by coordinating the folding, cleavage, and modification of nascent pre-ribosomal RNA (rRNA). Here, we present the cryo-electron microscopy structure of the yeast SSU processome at 5.1-angstrom resolution. The structure reveals how large ribosome biogenesis complexes assist the 5' external transcribed spacer and U3 small nucleolar RNA in providing an intertwined RNA-protein assembly platform for the separate maturation of 18S rRNA domains. The strategic placement of a molecular motor at the center of the particle further suggests a mechanism for mediating conformational changes within this giant particle. This study provides a structural framework for a mechanistic understanding of eukaryotic ribosome assembly in the model organism Saccharomyces cerevisiae.
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Affiliation(s)
- Malik Chaker-Margot
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA.,Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, NY 10065, USA
| | - Jonas Barandun
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Mirjam Hunziker
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA.
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8
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Hunziker M, Barandun J, Petfalski E, Tan D, Delan-Forino C, Molloy KR, Kim KH, Dunn-Davies H, Shi Y, Chaker-Margot M, Chait BT, Walz T, Tollervey D, Klinge S. UtpA and UtpB chaperone nascent pre-ribosomal RNA and U3 snoRNA to initiate eukaryotic ribosome assembly. Nat Commun 2016; 7:12090. [PMID: 27354316 PMCID: PMC4931317 DOI: 10.1038/ncomms12090] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/27/2016] [Indexed: 01/14/2023] Open
Abstract
Early eukaryotic ribosome biogenesis involves large multi-protein complexes, which co-transcriptionally associate with pre-ribosomal RNA to form the small subunit processome. The precise mechanisms by which two of the largest multi-protein complexes—UtpA and UtpB—interact with nascent pre-ribosomal RNA are poorly understood. Here, we combined biochemical and structural biology approaches with ensembles of RNA–protein cross-linking data to elucidate the essential functions of both complexes. We show that UtpA contains a large composite RNA-binding site and captures the 5′ end of pre-ribosomal RNA. UtpB forms an extended structure that binds early pre-ribosomal intermediates in close proximity to architectural sites such as an RNA duplex formed by the 5′ ETS and U3 snoRNA as well as the 3′ boundary of the 18S rRNA. Both complexes therefore act as vital RNA chaperones to initiate eukaryotic ribosome assembly. Eukaryotic ribosome biogenesis involves a large number of maturations factors which are responsible for the stepwise assembly of the ribosomal subunits. Here the authors use an array of biochemical and structural biology methods to investigate the function of the UtpA and UtpB complexes as part of the small subunit processome.
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Affiliation(s)
- Mirjam Hunziker
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Jonas Barandun
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Elisabeth Petfalski
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Dongyan Tan
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Clémentine Delan-Forino
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Kelly R Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Kelly H Kim
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, New York 10065, USA
| | - Hywel Dunn-Davies
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Yi Shi
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Malik Chaker-Margot
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.,Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, New York 10065, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, New York 10065, USA
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
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9
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Zhang C, Sun Q, Chen R, Chen X, Lin J, Ye K. Integrative structural analysis of the UTPB complex, an early assembly factor for eukaryotic small ribosomal subunits. Nucleic Acids Res 2016; 44:7475-86. [PMID: 27330138 PMCID: PMC5009746 DOI: 10.1093/nar/gkw562] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/10/2016] [Indexed: 12/28/2022] Open
Abstract
Ribosome assembly is an essential and conserved cellular process in eukaryotes that requires numerous assembly factors. The six-subunit UTPB complex is an essential component of the 90S precursor of the small ribosomal subunit. Here, we analyzed the molecular architecture of UTPB using an integrative structural biology approach. We mapped the major interactions that associate each of six UTPB proteins. Crystallographic studies showed that Utp1, Utp21, Utp12 and Utp13 are evolutionarily related and form a dimer of dimers (Utp1–Utp21, Utp12–Utp13) through their homologous helical C-terminal domains. Molecular docking with crosslinking restraints showed that the WD domains of Utp12 and Utp13 are associated, as are the WD domains of Utp1, Utp21 and Utp18. Electron microscopy images of the entire UTPB complex revealed that it predominantly adopts elongated conformations and possesses internal flexibility. We also determined crystal structures of the WD domain of Utp18 and the HAT and deviant HAT domains of Utp6. A structural model of UTPB was derived based on these data.
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Affiliation(s)
- Cheng Zhang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Qi Sun
- National Institute of Biological Sciences, Beijing 102206, China Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Tsinghua University, Beijing 100084, China Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China Beijing Key Laboratory of Noncoding RNA, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongchang Chen
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China Beijing Key Laboratory of Noncoding RNA, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xining Chen
- National Institute of Biological Sciences, Beijing 102206, China
| | - Jinzhong Lin
- National Institute of Biological Sciences, Beijing 102206, China
| | - Keqiong Ye
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China Beijing Key Laboratory of Noncoding RNA, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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10
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Zhang Q, Harding R, Hou F, Dong A, Walker JR, Bteich J, Tong Y. Structural Basis of the Recruitment of Ubiquitin-specific Protease USP15 by Spliceosome Recycling Factor SART3. J Biol Chem 2016; 291:17283-92. [PMID: 27255711 DOI: 10.1074/jbc.m116.740787] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Indexed: 12/21/2022] Open
Abstract
Ubiquitin-specific proteases (USPs) USP15 and USP4 belong to a subset of USPs featuring an N-terminal tandem domain in USP (DUSP) and ubiquitin-like (UBL) domain. Squamous cell carcinoma antigen recognized by T-cell 3 (SART3), a spliceosome recycling factor, binds to the DUSP-UBL domain of USP15 and USP4, recruiting them to the nucleus from the cytosol to control deubiquitination of histone H2B and spliceosomal proteins, respectively. To provide structural insight, we solved crystal structures of SART3 in the apo-form and in complex with the DUSP-UBL domain of USP15 at 2.0 and 3.0 Å, respectively. Structural analysis reveals SART3 contains 12 half-a-tetratricopeptide (HAT) repeats, organized into two subdomains, HAT-N and HAT-C. SART3 dimerizes through the concave surface of HAT-C, whereas the HAT-C convex surface binds USP15 in a novel bipartite mode. Isothermal titration calorimetry measurements and mutagenesis analysis confirmed key residues of USP15 involved in the interaction and indicated USP15 binds 20-fold stronger than USP4.
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Affiliation(s)
- Qi Zhang
- From the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7
| | - Rachel Harding
- From the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7
| | - Feng Hou
- From the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7
| | - Aiping Dong
- From the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7
| | - John R Walker
- From the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7
| | - Joseph Bteich
- the Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, and
| | - Yufeng Tong
- From the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, the Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5G 1L7, Canada
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11
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Pöll G, Li S, Ohmayer U, Hierlmeier T, Milkereit P, Perez-Fernandez J. In vitro reconstitution of yeast tUTP/UTP A and UTP B subcomplexes provides new insights into their modular architecture. PLoS One 2014; 9:e114898. [PMID: 25501974 PMCID: PMC4264851 DOI: 10.1371/journal.pone.0114898] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/14/2014] [Indexed: 11/29/2022] Open
Abstract
Eukaryotic ribosome biogenesis is a multistep process involving more than 150 biogenesis factors, which interact transiently with pre-ribosomal particles to promote their maturation. Some of these auxiliary proteins have been isolated in complexes found separate from the ribosomal environment. Among them, are 3 large UTP subcomplexes containing 6 or 7 protein subunits which are involved in the early steps of ribosome biogenesis. The composition of the UTP subcomplexes and the network of binary interactions between protein subunits have been analyzed previously. To obtain further insights into the structural and biochemical properties of UTP subcomplexes, we established a heterologous expression system to allow reconstitution of the yeast tUTP/UTP A and UTP B subcomplexes from their candidate subunits. The results of a series of reconstitution experiments involving different combinations of protein subunits are in good agreement with most of the previously observed binary interactions. Moreover, in combination with additional biochemical analyses, several stable building blocks of the UTP subcomplexes were identified. Based on these findings, we present a refined model of the tUTP/UTP A and UTP B architecture.
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Affiliation(s)
- Gisela Pöll
- Lehrstuhl für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Shuang Li
- Lehrstuhl für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Uli Ohmayer
- Lehrstuhl für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Thomas Hierlmeier
- Lehrstuhl für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Philipp Milkereit
- Lehrstuhl für Biochemie III, Universität Regensburg, Regensburg, Germany
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12
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ZFC3H1, a zinc finger protein, modulates IL-8 transcription by binding with celastramycin A, a potential immune suppressor. PLoS One 2014; 9:e108957. [PMID: 25268596 PMCID: PMC4182580 DOI: 10.1371/journal.pone.0108957] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 09/06/2014] [Indexed: 11/19/2022] Open
Abstract
Celastramycin A, a small molecule that inhibits the production of antibacterial peptides in an ex vivo culture system of Drosophila, suppresses the TNFα-mediated induction of IL-8 in mammalian cells. To understand its molecular mechanism, we examined Celastramycin A binding proteins and investigated their biological functions. Our screening and subsequent pull-down assay revealed ZFC3H1 (also known as CCDC131 or CSRC2), an uncharacterized zinc finger protein, as a Celastramycin A binding protein. The knockdown of ZFC3H1 reduced IL-8 expression levels in the TNFα-stimulated lung carcinoma cell line, LU99, and UV-irradiated HeLa cells. Based on reporter assay results, we concluded that ZFC3H1 participates in the transcriptional activation of IL-8. The findings of our UV-irradiation experiments implied that ZFC3H1 may indirectly interact with ERCC1 in an activated DNA repair complex. Thus, we designated ZFC3H1 as a mammalian target of Celastramycin A (mTOC).
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13
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Zheng S, Lan P, Liu X, Ye K. Interaction between ribosome assembly factors Krr1 and Faf1 is essential for formation of small ribosomal subunit in yeast. J Biol Chem 2014; 289:22692-22703. [PMID: 24990943 DOI: 10.1074/jbc.m114.584490] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Ribosome formation in Saccharomyces cerevisiae requires a large number of transiently associated assembly factors that coordinate processing and folding of pre-rRNA and binding of ribosomal proteins. Krr1 and Faf1 are two interacting proteins present in early 90 S precursor particles of the small ribosomal subunit. Here, we determined a co-crystal structure of the core domain of Krr1 bound to a 19-residue fragment of Faf1 at 2.8 Å resolution. The structure reveals that Krr1 consists of two packed K homology (KH) domains, KH1 and KH2, and resembles archaeal Dim2-like proteins. We show that KH1 is a divergent KH domain that lacks the RNA-binding GXXG motif and is involved in binding another assembly factor, Kri1. KH2 contains a canonical RNA-binding surface and additionally associates with an α-helix of Faf1. Specific disruption of the Krr1-Faf1 interaction impaired early 18 S rRNA processing at sites A0, A1, and A2 and caused cell lethality, but it did not prevent incorporation of the two proteins into pre-ribosomes. The Krr1-Faf1 interaction likely maintains a critical conformation of 90 S pre-ribosomes required for pre-rRNA processing. Our results illustrate the versatility of KH domains in protein interaction and provide insight into the role of Krr1-Faf1 interaction in ribosome biogenesis.
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Affiliation(s)
- Sanduo Zheng
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Beijing Normal University, Beijing 100875,; National Institute of Biological Sciences at Beijing, Beijing 102206, and
| | - Pengfei Lan
- National Institute of Biological Sciences at Beijing, Beijing 102206, and; Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100730
| | - Ximing Liu
- National Institute of Biological Sciences at Beijing, Beijing 102206, and
| | - Keqiong Ye
- National Institute of Biological Sciences at Beijing, Beijing 102206, and; Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100730,; Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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14
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Assembly and nuclear export of pre-ribosomal particles in budding yeast. Chromosoma 2014; 123:327-44. [PMID: 24817020 DOI: 10.1007/s00412-014-0463-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 03/18/2014] [Accepted: 04/07/2014] [Indexed: 11/27/2022]
Abstract
The ribosome is responsible for the final step of decoding genetic information into proteins. Therefore, correct assembly of ribosomes is a fundamental task for all living cells. In eukaryotes, the construction of the ribosome which begins in the nucleolus requires coordinated efforts of >350 specialized factors that associate with pre-ribosomal particles at distinct stages to perform specific assembly steps. On their way through the nucleus, diverse energy-consuming enzymes are thought to release assembly factors from maturing pre-ribosomal particles after accomplishing their task(s). Subsequently, recruitment of export factors prepares pre-ribosomal particles for transport through nuclear pore complexes. Pre-ribosomes are exported into the cytoplasm in a functionally inactive state, where they undergo final maturation before initiating translation. Accumulating evidence indicates a tight coupling between nuclear export, cytoplasmic maturation, and final proofreading of the ribosome. In this review, we summarize our current understanding of nuclear export of pre-ribosomal subunits and cytoplasmic maturation steps that render pre-ribosomal subunits translation-competent.
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15
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Venturin M, Carra S, Gaudenzi G, Brunelli S, Gallo GR, Moncini S, Cotelli F, Riva P. ADAP2 in heart development: a candidate gene for the occurrence of cardiovascular malformations in NF1 microdeletion syndrome. J Med Genet 2014; 51:436-43. [PMID: 24711647 DOI: 10.1136/jmedgenet-2013-102240] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Cardiovascular malformations have a higher incidence in patients with NF1 microdeletion syndrome compared to NF1 patients with intragenic mutation, presumably owing to haploinsufficiency of one or more genes included in the deletion interval and involved in heart development. In order to identify which genes could be responsible for cardiovascular malformations in the deleted patients, we carried out expression studies in mouse embryos and functional studies in zebrafish. METHODS AND RESULTS The expression analysis of three candidate genes included in the NF1 deletion interval, ADAP2, SUZ12 and UTP6, performed by in situ hybridisation, showed the expression of ADAP2 murine ortholog in heart during fundamental phases of cardiac morphogenesis. In order to investigate the role of ADAP2 in cardiac development, we performed loss-of-function experiments of zebrafish ADAP2 ortholog, adap2, by injecting two different morpholino oligos (adap2-MO and UTR-adap2-MO). adap2-MOs-injected embryos (morphants) displayed in vivo circulatory and heart shape defects. The molecular characterisation of morphants with cardiac specific markers showed that the injection of adap2-MOs causes defects in heart jogging and looping. Additionally, morphological and molecular analysis of adap2 morphants demonstrated that the loss of adap2 function leads to defective valvulogenesis, suggesting a correlation between ADAP2 haploinsufficiency and the occurrence of valve defects in NF1-microdeleted patients. CONCLUSIONS Overall, our findings indicate that ADAP2 has a role in heart development, and might be a reliable candidate gene for the occurrence of cardiovascular malformations in patients with NF1 microdeletion and, more generally, for the occurrence of a subset of congenital heart defects.
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Affiliation(s)
- Marco Venturin
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
| | - Silvia Carra
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Germano Gaudenzi
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Silvia Brunelli
- Dipartimento di Scienze della Salute, Università degli Studi di Milano-Bicocca, Monza (MB), Italy
| | | | - Silvia Moncini
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
| | - Franco Cotelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Paola Riva
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
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16
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The ribosomal biogenesis protein Utp21 interacts with Hsp90 and has differing requirements for Hsp90-associated proteins. PLoS One 2014; 9:e92569. [PMID: 24647762 PMCID: PMC3960262 DOI: 10.1371/journal.pone.0092569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 02/24/2014] [Indexed: 01/11/2023] Open
Abstract
The molecular chaperone Hsp90 buffers the effects of genetic variation by assisting the stabilization and folding of multiple clients critical for cell signaling and growth. We identified an interaction of Hsp90 and associated proteins with the essential nucleolar protein, Utp21, part of a large complex required for biogenesis of the small ribosomal subunit. The utp21-S602F mutation, which causes minor defects in otherwise wild-type yeast, exhibited severe or lethal growth defects when combined with mutations in Hsp90 or co-chaperones. WT Utp21 and Utp21-S602F exhibited similar interactions with Hsp90, and steady-state levels of WT Utp21 were reduced upon Hsp90 mutation or inhibition. Mutations in the human homolog of UTP21, WDR36, have been associated with adult-onset primary open-angle glaucoma, a leading cause of blindness worldwide. Three different mutant forms of Utp21 analogous to glaucoma-associated WDR36 mutations exhibit reduced levels in yeast cells expressing mutations in Hsp90 or associated chaperones, suggesting that Hsp90 and co-chaperones buffer the effects of those mutations.
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17
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Zhang C, Lin J, Liu W, Chen X, Chen R, Ye K. Structure of Utp21 tandem WD domain provides insight into the organization of the UTPB complex involved in ribosome synthesis. PLoS One 2014; 9:e86540. [PMID: 24466140 PMCID: PMC3897721 DOI: 10.1371/journal.pone.0086540] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 12/12/2013] [Indexed: 11/30/2022] Open
Abstract
Assembly of the eukaryotic ribosome requires a large number of trans-acting proteins and small nucleolar RNAs that transiently associate with the precursor rRNA to facilitate its modification, processing and binding with ribosomal proteins. UTPB is a large evolutionarily conserved complex in the 90S small subunit processome that mediates early processing of 18S rRNA. UTPB consists of six proteins Utp1/Pwp1, Utp6, Utp12/Dip2, Utp13, Utp18 and Utp21 and has abundant WD domains. Here, we determined the crystal structure of the tandem WD domain of yeast Utp21 at 2.1 Å resolution, revealing two open-clamshell-shaped β-propellers. The bottom faces of both WD domains harbor several conserved patches that potentially function as molecular binding sites. We show that residues 100–190 of Utp18 bind to the tandem WD domain of Utp21. Structural mapping of previous crosslinking data shows that the WD domains of Utp18 and Utp1 are organized on two opposite sides of the Utp21 WD domains. This study reports the first structure of a UTPB component and provides insight into the structural organization of the UTPB complex.
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Affiliation(s)
- Cheng Zhang
- Institute of Developmental Biology and Molecular Medicine, School of Life Science, Fudan University, Shanghai, China
- National Institute of Biological Sciences, Beijing, Beijing, China
| | - Jinzhong Lin
- National Institute of Biological Sciences, Beijing, Beijing, China
| | - Weixiao Liu
- National Institute of Biological Sciences, Beijing, Beijing, China
| | - Xining Chen
- National Institute of Biological Sciences, Beijing, Beijing, China
| | - Rongchang Chen
- National Institute of Biological Sciences, Beijing, Beijing, China
| | - Keqiong Ye
- National Institute of Biological Sciences, Beijing, Beijing, China
- * E-mail:
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18
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Soltanieh S, Lapensée M, Dragon F. Nucleolar proteins Bfr2 and Enp2 interact with DEAD-box RNA helicase Dbp4 in two different complexes. Nucleic Acids Res 2013; 42:3194-206. [PMID: 24357410 PMCID: PMC3950691 DOI: 10.1093/nar/gkt1293] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Different pre-ribosomal complexes are formed during ribosome biogenesis, and the composition of these complexes is highly dynamic. Dbp4, a conserved DEAD-box RNA helicase implicated in ribosome biogenesis, interacts with nucleolar proteins Bfr2 and Enp2. We show that, like Dbp4, Bfr2 and Enp2 are required for the early processing steps leading to the production of 18S ribosomal RNA. We also found that Bfr2 and Enp2 associate with the U3 small nucleolar RNA (snoRNA), the U3-specific protein Mpp10 and various pre-18S ribosomal RNA species. Thus, we propose that Bfr2, Dbp4 and Enp2 are components of the small subunit (SSU) processome, a large complex of ∼80S. Sucrose gradient sedimentation analyses indicated that Dbp4, Bfr2 and Enp2 sediment in a peak of ∼50S and in a peak of ∼80S. Bfr2, Dbp4 and Enp2 associate together in the 50S complex, which does not include the U3 snoRNA; however, they associate with U3 snoRNA in the 80S complex (SSU processome). Immunoprecipitation experiments revealed that U14 snoRNA associates with Dbp4 in the 50S complex, but not with Bfr2 or Enp2. The assembly factor Tsr1 is not part of the '50S' complex, indicating this complex is not a pre-40S ribosome. A combination of experiments leads us to propose that Bfr2, Enp2 and Dbp4 are recruited at late steps during assembly of the SSU processome.
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Affiliation(s)
- Sahar Soltanieh
- Département des sciences biologiques and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Québec, Canada
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19
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Woolford JL, Baserga SJ. Ribosome biogenesis in the yeast Saccharomyces cerevisiae. Genetics 2013; 195:643-81. [PMID: 24190922 PMCID: PMC3813855 DOI: 10.1534/genetics.113.153197] [Citation(s) in RCA: 548] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/26/2013] [Indexed: 01/09/2023] Open
Abstract
Ribosomes are highly conserved ribonucleoprotein nanomachines that translate information in the genome to create the proteome in all cells. In yeast these complex particles contain four RNAs (>5400 nucleotides) and 79 different proteins. During the past 25 years, studies in yeast have led the way to understanding how these molecules are assembled into ribosomes in vivo. Assembly begins with transcription of ribosomal RNA in the nucleolus, where the RNA then undergoes complex pathways of folding, coupled with nucleotide modification, removal of spacer sequences, and binding to ribosomal proteins. More than 200 assembly factors and 76 small nucleolar RNAs transiently associate with assembling ribosomes, to enable their accurate and efficient construction. Following export of preribosomes from the nucleus to the cytoplasm, they undergo final stages of maturation before entering the pool of functioning ribosomes. Elaborate mechanisms exist to monitor the formation of correct structural and functional neighborhoods within ribosomes and to destroy preribosomes that fail to assemble properly. Studies of yeast ribosome biogenesis provide useful models for ribosomopathies, diseases in humans that result from failure to properly assemble ribosomes.
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Affiliation(s)
- John L. Woolford
- Department of Biological Sciences, Center for Nucleic Acids Science and Technology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Susan J. Baserga
- Molecular Biophysics and Biochemistry, Genetics and Therapeutic Radiology, Yale University, New Haven, Connecticut 06520-8024
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20
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Hammani K, Bonnard G, Bouchoucha A, Gobert A, Pinker F, Salinas T, Giegé P. Helical repeats modular proteins are major players for organelle gene expression. Biochimie 2013; 100:141-50. [PMID: 24021622 DOI: 10.1016/j.biochi.2013.08.031] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 08/30/2013] [Indexed: 11/18/2022]
Abstract
Mitochondria and chloroplasts are often described as semi-autonomous organelles because they have retained a genome. They thus require fully functional gene expression machineries. Many of the required processes going all the way from transcription to translation have specificities in organelles and arose during eukaryote history. Most factors involved in these RNA maturation steps have remained elusive for a long time. The recent identification of a number of novel protein families including pentatricopeptide repeat proteins, half-a-tetratricopeptide proteins, octotricopeptide repeat proteins and mitochondrial transcription termination factors has helped to settle long-standing questions regarding organelle gene expression. In particular, their functions have been related to replication, transcription, RNA processing, RNA editing, splicing, the control of RNA turnover and translation throughout eukaryotes. These families of proteins, although evolutionary independent, seem to share a common overall architecture. For all of them, proteins contain tandem arrays of repeated motifs. Each module is composed of two to three α-helices and their succession forms a super-helix. Here, we review the features characterising these protein families, in particular, their distribution, the identified functions and mode of action and propose that they might share similar substrate recognition mechanisms.
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21
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Translatome analysis of CHO cells to identify key growth genes. J Biotechnol 2013; 167:215-24. [PMID: 23876478 DOI: 10.1016/j.jbiotec.2013.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 06/14/2013] [Accepted: 07/10/2013] [Indexed: 11/20/2022]
Abstract
We report the first investigation of translational efficiency on a global scale, also known as translatome, of a Chinese hamster ovary (CHO) DG44 cell line producing monoclonal antibodies (mAb). The translatome data was generated via combined use of high resolution and streamlined polysome profiling technology and proprietary Nimblegen microarrays probing for more than 13K annotated CHO-specific genes. The distribution of ribosome loading during the exponential growth phase revealed the translational activity corresponding to the maximal growth rate, thus allowing us to identify stably and highly translated genes encoding heterogeneous nuclear ribonucleoproteins (Hnrnpc and Hnrnpa2b1), protein regulator of cytokinesis 1 (Prc1), glucose-6-phosphate dehydrogenase (G6pdh), UTP6 small subunit processome (Utp6) and RuvB-like protein 1 (Ruvbl1) as potential key players for cellular growth. Moreover, correlation analysis between transcriptome and translatome data sets showed that transcript level and translation efficiency were uncoupled for 95% of investigated genes, suggesting the implication of translational control mechanisms such as the mTOR pathway. Thus, the current translatome analysis platform offers new insights into gene expression in CHO cell cultures by bridging the gap between transcriptome and proteome data, which will enable researchers of the bioprocessing field to prioritize in high-potential candidate genes and to devise optimal strategies for cell engineering toward improving culture performance.
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22
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Sousounis K, Looso M, Maki N, Ivester CJ, Braun T, Tsonis PA. Transcriptome analysis of newt lens regeneration reveals distinct gradients in gene expression patterns. PLoS One 2013; 8:e61445. [PMID: 23613853 PMCID: PMC3628982 DOI: 10.1371/journal.pone.0061445] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/09/2013] [Indexed: 12/11/2022] Open
Abstract
Regeneration of the lens in newts is quite a unique process. The lens is removed in its entirety and regeneration ensues from the pigment epithelial cells of the dorsal iris via transdifferentiation. The same type of cells from the ventral iris are not capable of regenerating a lens. It is, thus, expected that differences between dorsal and ventral iris during the process of regeneration might provide important clues pertaining to the mechanism of regeneration. In this paper, we employed next generation RNA-seq to determine gene expression patterns during lens regeneration in Notophthalmus viridescens. The expression of more than 38,000 transcripts was compared between dorsal and ventral iris. Although very few genes were found to be dorsal- or ventral-specific, certain groups of genes were up-regulated specifically in the dorsal iris. These genes are involved in cell cycle, gene regulation, cytoskeleton and immune response. In addition, the expression of six highly regulated genes, TBX5, FGF10, UNC5B, VAX2, NR2F5, and NTN1, was verified using qRT-PCR. These graded gene expression patterns provide insight into the mechanism of lens regeneration, the markers that are specific to dorsal or ventral iris, and layout a map for future studies in the field.
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Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Mario Looso
- Department of Bioinformatics, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Nobuyasu Maki
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Clifford J. Ivester
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- * E-mail: (TB); (PAT)
| | - Panagiotis A. Tsonis
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
- * E-mail: (TB); (PAT)
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23
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Yang B, Wu YJ, Zhu M, Fan SB, Lin J, Zhang K, Li S, Chi H, Li YX, Chen HF, Luo SK, Ding YH, Wang LH, Hao Z, Xiu LY, Chen S, Ye K, He SM, Dong MQ. Identification of cross-linked peptides from complex samples. Nat Methods 2012; 9:904-6. [DOI: 10.1038/nmeth.2099] [Citation(s) in RCA: 447] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 05/28/2012] [Indexed: 11/09/2022]
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24
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Matsumura H, Kusaka N, Nakamura T, Tanaka N, Sagegami K, Uegaki K, Inoue T, Mukai Y. Crystal structure of the N-terminal domain of the yeast general corepressor Tup1p and its functional implications. J Biol Chem 2012; 287:26528-38. [PMID: 22707714 DOI: 10.1074/jbc.m112.369652] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast Cyc8p-Tup1p protein complex is a general transcriptional corepressor of genes involved in many different physiological processes. Herein, we present the crystal structure of the Tup1p N-terminal domain (residues 1-92), essential for Tup1p self-assembly and interaction with Cyc8p. This domain tetramerizes to form a novel antiparallel four-helix bundle. Coiled coil interactions near the helical ends hold each dimer together, whereas interdimeric association involves only two sets of two residues located toward the chain centers. A mutagenesis study confirmed that the nonpolar residues responsible for the association of the protomers as dimers are also required for transcriptional repression. An additional structural study demonstrated that the domain containing an Leu(62) → Arg mutation that had been shown not to bind Cyc8p exhibits an altered structure, distinct from the wild type. This altered structure explains why the mutant cannot bind Cyc8p. The data presented herein highlight the importance of the architecture of the Tup1p N-terminal domain for self-association.
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Affiliation(s)
- Hiroyoshi Matsumura
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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25
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RNA binding and RNA remodeling activities of the half-a-tetratricopeptide (HAT) protein HCF107 underlie its effects on gene expression. Proc Natl Acad Sci U S A 2012; 109:5651-6. [PMID: 22451905 DOI: 10.1073/pnas.1200318109] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The half-a-tetratricopeptide repeat (HAT) motif is a helical repeat motif found in proteins that influence various aspects of RNA metabolism, including rRNA biogenesis, RNA splicing, and polyadenylation. This functional association with RNA suggested that HAT repeat tracts might bind RNA. However, RNA binding activity has not been reported for any HAT repeat tract, and recent literature has emphasized a protein binding role. In this study, we show that a chloroplast-localized HAT protein, HCF107, is a sequence-specific RNA binding protein. HCF107 consists of 11 tandem HAT repeats and short flanking regions that are also predicted to form helical hairpins. The minimal HCF107 binding site spans ∼11 nt, consistent with the possibility that HAT repeats bind RNA through a modular one repeat-1 nt mechanism. Binding of HCF107 to its native RNA ligand in the psbH 5' UTR remodels local RNA structure and protects the adjacent RNA from exonucleases in vitro. These activities can account for the RNA stabilizing, RNA processing, and translational activation functions attributed to HCF107 based on genetic data. We suggest that analogous activities contribute to the functions of HAT domains found in ribonucleoprotein complexes in the nuclear-cytosolic compartment.
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26
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Bonnart C, Gérus M, Hoareau-Aveilla C, Kiss T, Caizergues-Ferrer M, Henry Y, Henras AK. Mammalian HCA66 protein is required for both ribosome synthesis and centriole duplication. Nucleic Acids Res 2012; 40:6270-89. [PMID: 22434888 PMCID: PMC3401428 DOI: 10.1093/nar/gks234] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ribosome production, one of the most energy-consuming biosynthetic activities in living cells, is adjusted to growth conditions and coordinated with the cell cycle. Connections between ribosome synthesis and cell cycle progression have been described, but the underlying mechanisms remain only partially understood. The human HCA66 protein was recently characterized as a component of the centrosome, the major microtubule-organizing center (MTOC) in mammalian cells, and was shown to be required for centriole duplication and assembly of the mitotic spindle. We show here that HCA66 is also required for nucleolar steps of the maturation of the 40S ribosomal subunit and therefore displays a dual function. Overexpression of a dominant negative version of HCA66, accumulating at the centrosome but absent from the nucleoli, alters centrosome function but has no effect on pre-rRNA processing, suggesting that HCA66 acts independently in each process. In yeast and HeLa cells, depletion of MTOC components does not impair ribosome synthesis. Hence our results suggest that both in yeast and human cells, assembly of a functional MTOC and ribosome synthesis are not closely connected processes.
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Affiliation(s)
- Chrystelle Bonnart
- Centre National de la Recherche Scientifique, Laboratoire de Biologie Moléculaire Eucaryote, Toulouse, France
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Phipps KR, Charette JM, Baserga SJ. The small subunit processome in ribosome biogenesis—progress and prospects. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 2:1-21. [PMID: 21318072 DOI: 10.1002/wrna.57] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The small subunit (SSU) processome is a 2.2-MDa ribonucleoprotein complex involved in the processing, assembly, and maturation of the SSU of eukaryotic ribosomes. The identities of many of the factors involved in SSU biogenesis have been elucidated over the past 40 years. However, as our understanding increases, so do the number of questions about the nature of this complicated process. Cataloging the components is the first step toward understanding the molecular workings of a system. This review will focus on how identifying components of ribosome biogenesis has led to the knowledge of how these factors, protein and RNA alike, associate with one another into subcomplexes, with a concentration on the small ribosomal subunit. We will also explore how this knowledge of subcomplex assembly has informed our understanding of the workings of the ribosome synthesis system as a whole.
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Affiliation(s)
- Kathleen R Phipps
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
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28
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Mukhopadhyay A, Ray S, De M. Detecting protein complexes in a PPI network: a gene ontology based multi-objective evolutionary approach. MOLECULAR BIOSYSTEMS 2012; 8:3036-48. [DOI: 10.1039/c2mb25302j] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Rawling DC, Baserga SJ. In vivo approaches to dissecting the function of RNA helicases in eukaryotic ribosome assembly. Methods Enzymol 2012; 511:289-321. [PMID: 22713326 DOI: 10.1016/b978-0-12-396546-2.00014-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In eukaryotes, ribosome biogenesis involves the nucleolar transcription and processing of pre-ribosomal RNA molecules (pre-rRNA) in a complex pathway requiring the participation of myriad protein and ribonucleoprotein factors. Through efforts aimed at categorizing and characterizing these factors, at least 20 RNA helicases have been shown to interact with or participate in the activities of the major ribosome biogenesis complexes. Unfortunately, little is known about the enzymatic properties of most of these helicases, and less is known about their roles in ribosome biogenesis and pre-rRNA maturation. This chapter presents approaches for characterizing RNA helicases involved in ribosome biogenesis. Included are methods for depletion of specific protein targets, with standard protocols for assaying the typical ribosome biogenesis defects that may result. Procedures and rationales for mutagenic studies of target proteins are discussed, as well as several approaches for identifying protein-protein interactions in order to determine functional context and potential cofactors of RNA helicases.
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Affiliation(s)
- David C Rawling
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, USA
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30
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Abstract
RNA helicases are involved in all aspects of RNA metabolism. Since the helicase core is conserved between all helicases, specificity for particular cellular roles must arise from interactions with specific cofactors, which can regulate RNA binding and enzymatic activity. While recent structural studies have provided invaluable insight into some mechanisms of cofactor effects on RNA helicases, biochemical experiments must ultimately be conducted in order to validate these predictions. Here, we provide a guide for identifying helicase-specific cofactors and then studying their effects on helicase function. By measuring RNA binding and release, ATPase activity, nucleotide affinity, and unwinding and annealing activities, cofactor effects on an RNA helicase can be fully characterized.
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31
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Inside the 40S ribosome assembly machinery. Curr Opin Chem Biol 2011; 15:657-63. [PMID: 21862385 DOI: 10.1016/j.cbpa.2011.07.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 12/29/2022]
Abstract
Ribosome assembly involves rRNA transcription, modification, folding and cleavage from precursor transcripts, and association of ribosomal proteins (Rps). In bacteria, this complex process requires only a handful of proteins in addition to those needed for rRNA transcription, modification and cleavage, while in eukaryotes a large machinery comprising ∼200 proteins in the yeast S. cerevisiae has been identified. Furthermore, while the bacterial assembly factors generally produce only cold-sensitive phenotypes upon deletion, most of the eukaryotic assembly factors are essential, comprising ∼20% of essential yeast proteins. This review explores recent rapid progress in the structural and functional dissection of the 40S assembly machinery.
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Footz T, Dubois S, Sarfarazi M, Raymond V, Walter MA. Co-variation of STI1 and WDR36/UTP21 alters cell proliferation in a glaucoma model. Mol Vis 2011; 17:1957-69. [PMID: 21850170 PMCID: PMC3154128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/12/2011] [Indexed: 10/26/2022] Open
Abstract
PURPOSE To investigate the role of multigenic variation in primary open-angle glaucoma (POAG) involving the rRNA processing gene WD repeat domain 36 (WDR36). METHODS We examined the heat shock protein 70/90 (HSP70/90)-organizing co-chaperone stress-induced-phosphoprotein 1 (STI1) as a potential co-modifying gene in glaucoma patients found to harbor WDR36 amino acid variation. The STI1 gene was sequenced and its POAG-associated amino acid variant K434R, as well as the single nucleotide polymorphism (SNP) P173T, were tested for functional defects in a yeast model system previously used to characterize WDR36 variants (using the homologous yeast gene U3 protein 21 [UTP21]). RESULTS A POAG patient heterozygous for the WDR36 variant L25P was discovered to also carry the STI1 variant K434R in a heterozygous state. Variant K434R, located at an evolutionarily-conserved site, was not found in a pool of clinically-examined individuals lacking WDR36 variation which included 55 normal controls and 20 patients with normal tension glaucoma (NTG). STI1 (K434R) and the homologous yeast variant K470R were able to rescue yeast growth-inhibition by the HSP90-inhibitor radicicol. Double mutant haploid strains expressing human STI1 (K434R) and recombinant yeast UTP21 variants did not have significantly different levels of 18S rRNA from the corresponding hSTI1 (WT) strains. However, specific double mutant K434R strains exhibited significantly slower culture growth at 37 °C. Double mutant P173T strains also displayed altered growth rates at 37 °C. CONCLUSIONS STI1 variation does not play a significant direct role in the genetics of POAG. However, as previously found for the STI1 null allele, non-synonymous variants of human STI1 confer growth dysregulation in the context of specific yeast UTP21 mutations and heat stress. Based on the genetic association of two co-heterozygous STI1 and WDR36 variants in a POAG patient and the functional analyses performed in a model system for basic eukaryotic cellular processes, these experiments point to a conserved molecular pathway involving STI1 and WDR36.
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Affiliation(s)
- Tim Footz
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Stéphane Dubois
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
| | - Mansoor Sarfarazi
- Molecular Ophthalmic Genetics Laboratory, University of Connecticut Health Center, Farmington, CT
| | - Vincent Raymond
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
| | - Michael A. Walter
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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Lim YH, Charette JM, Baserga SJ. Assembling a protein-protein interaction map of the SSU processome from existing datasets. PLoS One 2011; 6:e17701. [PMID: 21423703 PMCID: PMC3053386 DOI: 10.1371/journal.pone.0017701] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 02/08/2011] [Indexed: 01/12/2023] Open
Abstract
Background The small subunit (SSU) processome is a large ribonucleoprotein complex involved in small ribosomal subunit assembly. It consists of the U3 snoRNA and ∼72 proteins. While most of its components have been identified, the protein-protein interactions (PPIs) among them remain largely unknown, and thus the assembly, architecture and function of the SSU processome remains unclear. Methodology We queried PPI databases for SSU processome proteins to quantify the degree to which the three genome-wide high-throughput yeast two-hybrid (HT-Y2H) studies, the genome-wide protein fragment complementation assay (PCA) and the literature-curated (LC) datasets cover the SSU processome interactome. Conclusions We find that coverage of the SSU processome PPI network is remarkably sparse. Two of the three HT-Y2H studies each account for four and six PPIs between only six of the 72 proteins, while the third study accounts for as little as one PPI and two proteins. The PCA dataset has the highest coverage among the genome-wide studies with 27 PPIs between 25 proteins. The LC dataset was the most extensive, accounting for 34 proteins and 38 PPIs, many of which were validated by independent methods, thereby further increasing their reliability. When the collected data were merged, we found that at least 70% of the predicted PPIs have yet to be determined and 26 proteins (36%) have no known partners. Since the SSU processome is conserved in all Eukaryotes, we also queried HT-Y2H datasets from six additional model organisms, but only four orthologues and three previously known interologous interactions were found. This provides a starting point for further work on SSU processome assembly, and spotlights the need for a more complete genome-wide Y2H analysis.
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Affiliation(s)
- Young H. Lim
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - J. Michael Charette
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Susan J. Baserga
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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Woolls HA, Lamanna AC, Karbstein K. Roles of Dim2 in ribosome assembly. J Biol Chem 2011; 286:2578-86. [PMID: 21075849 PMCID: PMC3024753 DOI: 10.1074/jbc.m110.191494] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/12/2010] [Indexed: 12/25/2022] Open
Abstract
In eukaryotes, ribosome assembly requires hundreds of conserved essential proteins not present in the mature particle. Despite their importance, the function of most factors remains unknown. This is because protein deletion often affects the composition of the entire particle. Additionally, many proteins are present in assembling ribosomes for extended times, which makes it difficult to pinpoint their role to a particular step. Here we have combined classical yeast biochemistry with experiments using recombinant proteins and RNA to study the role of Dim2 and its interaction with Nob1, the nuclease that generates the 3'-end of 18 S rRNA. Analysis of Dim2 mutants in which the interaction with Nob1 is disrupted demonstrates that this interaction between Dim2 and Nob1 is essential for optimal growth, and RNA binding experiments show that Dim2 increases Nob1 RNA affinity. Furthermore, our data indicate that Dim2 helps regulate Nob1 cleavage activity at the 3'-end of 18 S rRNA, as point mutants where this interaction is abolished in vitro accumulate pre-ribosomes containing Nob1 and 20 S rRNA in vivo. Interestingly, the site of interaction with Nob1 is mapped to the canonical RNA binding surface of a KH-like domain in Dim2, providing another example where an RNA-binding domain can be repurposed for protein interactions.
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Affiliation(s)
| | - Allison C. Lamanna
- the Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Katrin Karbstein
- From the Program in Chemical Biology and
- the Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
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35
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Campbell MG, Karbstein K. Protein-protein interactions within late pre-40S ribosomes. PLoS One 2011; 6:e16194. [PMID: 21283762 PMCID: PMC3024409 DOI: 10.1371/journal.pone.0016194] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 12/07/2010] [Indexed: 12/28/2022] Open
Abstract
Ribosome assembly in eukaryotic organisms requires more than 200 assembly factors to facilitate and coordinate rRNA transcription, processing, and folding with the binding of the ribosomal proteins. Many of these assembly factors bind and dissociate at defined times giving rise to discrete assembly intermediates, some of which have been partially characterized with regards to their protein and RNA composition. Here, we have analyzed the protein-protein interactions between the seven assembly factors bound to late cytoplasmic pre-40S ribosomes using recombinant proteins in binding assays. Our data show that these factors form two modules: one comprising Enp1 and the export adaptor Ltv1 near the beak structure, and the second comprising the kinase Rio2, the nuclease Nob1, and a regulatory RNA binding protein Dim2/Pno1 on the front of the head. The GTPase-like Tsr1 and the universally conserved methylase Dim1 are also peripherally connected to this second module. Additionally, in an effort to further define the locations for these essential proteins, we have analyzed the interactions between these assembly factors and six ribosomal proteins: Rps0, Rps3, Rps5, Rps14, Rps15 and Rps29. Together, these results and previous RNA-protein crosslinking data allow us to propose a model for the binding sites of these seven assembly factors. Furthermore, our data show that the essential kinase Rio2 is located at the center of the pre-ribosomal particle and interacts, directly or indirectly, with every other assembly factor, as well as three ribosomal proteins required for cytoplasmic 40S maturation. These data suggest that Rio2 could play a central role in regulating cytoplasmic maturation steps.
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Affiliation(s)
- Melody G. Campbell
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Katrin Karbstein
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida, United States of America
- * E-mail:
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Charette JM, Baserga SJ. The DEAD-box RNA helicase-like Utp25 is an SSU processome component. RNA (NEW YORK, N.Y.) 2010; 16:2156-69. [PMID: 20884785 PMCID: PMC2957055 DOI: 10.1261/rna.2359810] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The SSU processome is a large ribonucleoprotein complex consisting of the U3 snoRNA and at least 43 proteins. A database search, initiated in an effort to discover additional SSU processome components, identified the uncharacterized, conserved and essential yeast nucleolar protein YIL091C/UTP25 as one such candidate. The C-terminal DUF1253 motif, a domain of unknown function, displays limited sequence similarity to DEAD-box RNA helicases. In the absence of the conserved DEAD-box sequence, motif Ia is the only clearly identifiable helicase element. Since the yeast homolog is nucleolar and interacts with components of the SSU processome, we examined its role in pre-rRNA processing. Genetic depletion of Utp25 resulted in slowed growth. Northern analysis of pre-rRNA revealed an 18S rRNA maturation defect at sites A₀, A₁, and A₂. Coimmunoprecipitation confirmed association with U3 snoRNA and with Mpp10, and with components of the t-Utp/UtpA, UtpB, and U3 snoRNP subcomplexes. Mutation of the conserved motif Ia residues resulted in no discernable temperature-sensitive or cold-sensitive growth defects, implying that this motif is dispensable for Utp25 function. A yeast two-hybrid screen of Utp25 against other SSU processome components revealed several interacting proteins, including Mpp10, Utp3, and Utp21, thereby identifying the first interactions among the different subcomplexes of the SSU processome. Furthermore, the DUF1253 domain is required and sufficient for the interaction of Utp25 with Utp3. Thus, Utp25 is a novel SSU processome component that, along with Utp3, forms the first identified interactions among the different SSU processome subcomplexes.
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Affiliation(s)
- J Michael Charette
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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37
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The tetratricopeptide repeats (TPR)-like superfamily of proteins in Leishmania spp., as revealed by multi-relational data mining. Pattern Recognit Lett 2010. [DOI: 10.1016/j.patrec.2010.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Lin YP, Chen LR, Chen CF, Liou JF, Chen YL, Yang JR, Shiue YL. Identification of early transcripts related to male development in chicken embryos. Theriogenology 2010; 74:1161-1178.e1-8. [PMID: 20728927 DOI: 10.1016/j.theriogenology.2010.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 05/08/2010] [Accepted: 05/15/2010] [Indexed: 01/21/2023]
Abstract
Early transcripts related to male development in chicken embryos and their expression profiles were examined. A total of 89 and 127 candidate male development transcripts that represented 83 known and 119 unknown non-redundant sequences, respectively, were characterized in an embryonic day 3 (E3; Hamburger and Hamilton Stage 20: HH20) male-subtract-female complementary DNA library. Of 35 selected transcripts, quantitative reverse transcription-polymerase chain reaction validated that the expression levels of 25 transcripts were higher in male E3 whole embryos than in females (P < 0.05). Twelve of these transcripts mapped to the Z chromosome. At 72 wk of age, 20 and 4 transcripts were expressed at higher levels in the testes and brains of male than in the ovaries and brains of female chickens (P < 0.05), respectively. Whole mount and frozen cross-section in situ hybridization, as well as Western blotting analysis further corroborated that riboflavin kinase (RFK), WD repeat domain 36 (WDR36), and EY505808 transcripts; RFK and WDR36 protein products were predominantly expressed in E7 male gonads. Treatment with an aromatase inhibitor formestane at E4 affected the expression levels at E7 of the coatomer protein complex (subunit beta 1), solute carrier family 35 member F1, LOC427316 and EY505812 transcripts across both sexes (P < 0.05), similar to what was observed for the doublesex and mab-3 related transcription factor 1 gene. The interaction effects of sex by formestane treatment were observed in 15 candidate male development transcripts (P < 0.05). Taken together, we identified a panel of potentially candidate male development transcripts during early chicken embryogenesis; some might be regulated by sex hormones.
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Affiliation(s)
- Yuan-Ping Lin
- Institute of Biomedical Science, National Sun Yat-sen University, Kaohsiung, Taiwan
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39
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Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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40
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Champion EA, Kundrat L, Regan L, Baserga SJ. A structural model for the HAT domain of Utp6 incorporating bioinformatics and genetics. Protein Eng Des Sel 2009; 22:431-9. [PMID: 19515729 DOI: 10.1093/protein/gzp022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The half-a-tetratricopeptide (HAT) repeat motif is of interest because it is found exclusively in proteins that are involved in RNA metabolism. Little is known about structure-function relationships in this class of repeat motif. Here, we present the results of a combined bioinformatics, modeling and mutagenesis study of the HAT domain of Utp6. We have derived a new HAT consensus, delineated its structure-defining residues and, by homology modeling, have placed these residues in a structural context. By considering only HAT motifs from Utp6 proteins, we identified residues that are shared by, and unique to, only this subset of HAT motifs, suggesting a key functional role. Employing both random and directed mutagenesis of the HAT domain in yeast Utp6, we have identified residues whose mutation results in loss of function. By examining these residues in the context of the homology model, we have delineated those that act by perturbing structure and those that more likely have a direct effect on function. Importantly, the residues we predict to have a direct effect on function map together on the tertiary structure, thus defining a potential functional interaction surface.
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Affiliation(s)
- Erica A Champion
- Departments of Genetics, Yale University, New Haven, CT 06520, USA
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41
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Wery M, Ruidant S, Schillewaert S, Leporé N, Lafontaine DLJ. The nuclear poly(A) polymerase and Exosome cofactor Trf5 is recruited cotranscriptionally to nucleolar surveillance. RNA (NEW YORK, N.Y.) 2009; 15:406-419. [PMID: 19141608 PMCID: PMC2657017 DOI: 10.1261/rna.1402709] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Accepted: 11/25/2008] [Indexed: 05/27/2023]
Abstract
Terminal balls detected at the 5'-end of nascent ribosomal transcripts act as pre-rRNA processing complexes and are detected in all eukaryotes examined, resulting in illustrious Christmas tree images. Terminal balls (also known as SSU-processomes) compaction reflects the various stages of cotranscriptional ribosome assembly. Here, we have followed SSU-processome compaction in vivo by use of a chromatin immunoprecipitation (Ch-IP) approach and shown, in agreement with electron microscopy analysis of Christmas trees, that it progressively condenses to come in close proximity to the 5'-end of the 25S rRNA gene. The SSU-processome is comprised of independent autonomous building blocks that are loaded onto nascent pre-rRNAs and assemble into catalytically active pre-rRNA processing complexes in a stepwise and highly hierarchical process. Failure to assemble SSU-processome subcomplexes with proper kinetics triggers a nucleolar surveillance pathway that targets misassembled pre-rRNAs otherwise destined to mature into small subunit 18S rRNA for polyadenylation, preferentially by TRAMP5, and degradation by the 3' to 5' exoribonucleolytic activity of the Exosome. Trf5 colocalized with nascent pre-rRNPs, indicating that this nucleolar surveillance initiates cotranscriptionally.
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Affiliation(s)
- Maxime Wery
- Fonds de la Recherche Scientifique (FRS-FNRS), AcadémieWallonie-Bruxelles, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, Charleroi-Gosselies, B-6041 Belgium
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Old and new faces of the nucleolus. Workshop on the Nucleolus and Disease. EMBO Rep 2008; 10:35-40. [PMID: 19079131 PMCID: PMC2613212 DOI: 10.1038/embor.2008.230] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Accepted: 11/17/2008] [Indexed: 12/03/2022] Open
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