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Sun C, Luo F, You Y, Gu M, Yang W, Yi C, Zhang W, Feng Z, Wang J, Hu W. MicroRNA-1 targets ribosomal protein genes to regulate the growth, development and reproduction of Schistosoma japonicum. Int J Parasitol 2023; 53:637-649. [PMID: 37355197 DOI: 10.1016/j.ijpara.2023.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/19/2023] [Accepted: 03/21/2023] [Indexed: 06/26/2023]
Abstract
Eggs laid by mature female schistosomes are primarily responsible for the pathogenesis of schistosomiasis and critical for transmission. Consequently, elucidating the mechanism of sexual maturation as well as egg production may lead to new strategies for the control of schistosomiasis. MicroRNAs (miRNAs) are involved in multiple biological processes including reproduction in many organisms, yet their roles have not been well characterized in schistosomes. Here, we investigated microRNA-1 (miR-1), which was downregulated gradually in both male and female Schistosoma japonicum after they reached sexually maturity. The expression of miR-1, as shown with quantitative reverse transcription PCR (qRT-PCR), was lower in the reproductive organs of adult females compared with the somatic tissues. Overexpression of miR-1 in adult worms destroyed the morphological architecture of reproductive organs and reduced the subsequent oviposition, which may be due to the activation of apoptosis pathways. Through in silico analysis, 34 potential target genes of miR-1 were identified, including five ribosomal protein genes, called rp-s13, rp-l7ae, rp-l14, rp-l11 and rp-s24e. In vitro dual-luciferase reporter gene assays and miRNA overexpression experiments further validated that these ribosomal protein genes were directly regulated by miR-1. In contrast to the gene expression of miR-1, qRT-PCR and in situ hybridization experiments demonstrated these ribosomal protein genes were enriched in the sexual organs of adult females. Using RNA interference to silence the ribosomal protein genes in different developmental stages in a mouse model system, we demonstrated that these miR-1 target genes not only participated in the reproductive development of S. japonicum, but also were required for the growth and survival of the parasite in the early developmental stages. Taken together, our data suggested that miR-1 may affect the growth, reproduction and oviposition of S. japonicum by targeting the ribosomal protein genes, which provides insights for exploration of new anti-schistosome strategies.
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Affiliation(s)
- Chengsong Sun
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China; Anhui Provincial Institute of Parasitic Diseases, No. 12560 Fanhua Avenue, Shushan District, Hefei 230601, Anhui Province, China
| | - Fang Luo
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yanmin You
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Mengjie Gu
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Wenbin Yang
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Cun Yi
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Wei Zhang
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Zheng Feng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of China Ministry of Health, WHO Collaborating Centre for Tropical Diseases, Joint Research Laboratory of Genetics and Ecology on Parasite-host Interaction, Chinese Center for Disease Control and Prevention and Fudan University, No.207 Ruijin Road II, Shanghai 200025, China
| | - Jipeng Wang
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China.
| | - Wei Hu
- Department of Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, No. 2005 Songhu Road, Yangpu District, Shanghai 200438, China; National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of China Ministry of Health, WHO Collaborating Centre for Tropical Diseases, Joint Research Laboratory of Genetics and Ecology on Parasite-host Interaction, Chinese Center for Disease Control and Prevention and Fudan University, No.207 Ruijin Road II, Shanghai 200025, China; College of Life Sciences, Inner Mongolia University, No. 235 Daxue West Road, Saihan District, Hohhot 010021, Inner Mongolia Autonomous Region, China.
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Hu R, Xu X, Mo L, Chen M, Liu Y. Bioinformatics analysis identifies potential biomarkers involved in the metastasis of locoregionally advanced nasopharyngeal carcinoma. Medicine (Baltimore) 2022; 101:e30126. [PMID: 36107539 PMCID: PMC9439843 DOI: 10.1097/md.0000000000030126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is one of the malignant epithelial tumors with a high metastasis rate. This study aimed to screen potential novel biomarkers involved in NPC metastasis. Microarray data of locoregionally advanced NPC (LA-NPC; GSE103611) were obtained from the database of Gene Expression Omnibus. The differentially expressed genes (DEGs) between LA-NPC tissues with and without distant metastasis after radical treatment were screened. Functional analysis was performed and the protein-protein interaction and submodule were analyzed. The univariate Cox regression analysis was performed to identify prognostic genes in NPC in the validation microarray dataset GSE102349. The drug-gene interactions and key genes were identified. Totally, 107 DEGs were identified. The upregulated DEGs and the key nodes in the protein-protein interaction network were associated with pathways or biological processes related to the cell cycle. Four genes including CD44, B2M, PTPN11, and TRIM74 were associated with disease-free survival in NPC. The drug-gene interaction analysis revealed that upregulated genes CXCL10, CD44, B2M, XRCC5, and RPL11 might be potential druggable genes for patients with LA-NPC metastasis by regulating cell cycle, autophagy, and drug resistance. Upregulated CXCL10, CD44, B2M, XRCC5, and RPL11 might play important roles in LA-NPC metastasis by regulating cell cycle-related pathways.
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Affiliation(s)
- Rongrong Hu
- Department of Otorhinolaryngology, Zhejiang University Hospital, Hangzhou, China
- *Correspondence: Rongrong Hu, Department of Otorhinolaryngology, Zhejiang University Hospital, No 73 Fengqi Road, Jianggan District, Hangzhou, Zhejiang, China (e-mail: ); Lujiao Mo, Department of Critical Care Medicine, The First People’s Hospital of Xiaoshan District, No. 199 Shixin Road, Xiaoshan District, Hangzhou 311200, China (e-mail: )
| | - Xujun Xu
- Department of Internal Medicine, Zhejiang University Hospital, Hangzhou, China
| | - Lujiao Mo
- Department of Critical Care Medicine, The First People’s Hospital of Xiaoshan District, Hangzhou, China
- *Correspondence: Rongrong Hu, Department of Otorhinolaryngology, Zhejiang University Hospital, No 73 Fengqi Road, Jianggan District, Hangzhou, Zhejiang, China (e-mail: ); Lujiao Mo, Department of Critical Care Medicine, The First People’s Hospital of Xiaoshan District, No. 199 Shixin Road, Xiaoshan District, Hangzhou 311200, China (e-mail: )
| | - Mengjie Chen
- General medicine, Community Health Service Center, Dangwan Town, Xiaoshan District, Hangzhou, China
| | - Yuxiang Liu
- Department of Critical Care Medicine, The Second People’s Hospital of Xiaoshan District, Hangzhou, China
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Lan T, Xiong W, Chen X, Mo B, Tang G. Plant cytoplasmic ribosomal proteins: an update on classification, nomenclature, evolution and resources. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:292-318. [PMID: 35000252 DOI: 10.1111/tpj.15667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/23/2021] [Accepted: 01/02/2022] [Indexed: 06/14/2023]
Abstract
Standardized naming systems are essential to integrate and unify distinct research fields, and to link multi-species data within and across kingdoms. We conducted a comprehensive survey of cytoplasmic ribosomal proteins (CRPs) in the dicot model Arabidopsis thaliana and the monocot model rice, noting that the standardized naming system has not been widely adopted in the plant community. We generated a database linking the old classical names to their updated and compliant names. We also explored the sequences, molecular evolution, and structural and functional characteristics of all plant CRP families, emphasizing evolutionarily conserved and plant-specific features through cross-kingdom comparisons. Unlike fungal CRP paralogs that were mainly created by whole-genome duplication (WGD) or retroposition under a concerted evolution mode, plant CRP genes evolved primarily through both WGD and tandem duplications in a rapid birth-and-death process. We also provide a web-based resource (http://www.plantcrp.cn/) with the aim of sharing the latest knowledge on plant CRPs and facilitating the continued development of a standardized framework across the entire community.
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Affiliation(s)
- Ting Lan
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Wei Xiong
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, 92521, CA, USA
| | - Beixin Mo
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Guiliang Tang
- Department of Biological Sciences, Life Science and Technology Institute, Michigan Technological University, Houghton, 49931, MI, USA
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Knockdown of the Ribosomal Protein eL29 in Mammalian Cells Leads to Significant Changes in Gene Expression at the Transcription Level. Cells 2020; 9:cells9051228. [PMID: 32429214 PMCID: PMC7291024 DOI: 10.3390/cells9051228] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 01/02/2023] Open
Abstract
An imbalance in the synthesis of ribosomal proteins can lead to the disruption of various cellular processes. For mammalian cells, it has been shown that the level of the eukaryote-specific ribosomal protein eL29, also known as the one interacting with heparin/heparan sulfate, substantially affects their growth. Moreover, in animals lacking this protein, a number of anatomical abnormalities have been observed. Here, we applied next-generation RNA sequencing to HEK293 cells transfected with siRNAs specific for the mRNA of eL29 to determine what changes occur in the transcriptome profile with a decrease in the level of the target protein. We showed that an approximately 2.5-fold decrease in the content of eL29 leads to statistically significant changes in the expression of more than a thousand genes at the transcription level, without a noticeable effect on cell viability, rRNA level, and global translation. The set of eL29-dependent genes included both up-regulated and down-regulated ones, among which there are those previously identified as targets for proteins implicated in oncogenesis. Thus, our findings demonstrate that an insufficiency of eL29 in mammalian cells causes a significant reorganization of gene expression, thereby highlighting the relationship between the cellular balance of eL29 and the activities of certain genes.
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5
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Jindal S, Ghosh A, Ismail A, Singh N, Komar AA. Role of the uS9/yS16 C-terminal tail in translation initiation and elongation in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 47:806-823. [PMID: 30481328 PMCID: PMC6344880 DOI: 10.1093/nar/gky1180] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 11/06/2018] [Indexed: 12/18/2022] Open
Abstract
The small ribosomal subunit protein uS9 (formerly called rpS16 in Saccharomyces cerevisiae), has a long protruding C-terminal tail (CTT) that extends towards the mRNA cleft of the ribosome. The last C-terminal residue of uS9 is an invariably conserved, positively charged Arg that is believed to enhance interaction of the negatively charged initiator tRNA with the ribosome when the tRNA is base-paired to the AUG codon in the P-site. In order to more fully characterize the role of the uS9 CTT in eukaryotic translation, we tested how truncations, extensions and substitutions within the CTT affect initiation and elongation processes in Saccharomyces cerevisiae. We found that uS9 C-terminal residues are critical for efficient recruitment of the eIF2•GTP•Met-tRNAiMet ternary complex to the ribosome and for its proper response to the presence of an AUG codon in the P-site during the scanning phase of initiation. These residues also regulate hydrolysis of the GTP in the eIF2•GTP•Met-tRNAiMet complex to GDP and Pi. In addition, our data show that uS9 CTT modulates elongation fidelity. Therefore, we propose that uS9 CTT is critical for proper control of the complex interplay of events surrounding accommodation of initiator and elongator tRNAs in the P- and A-sites of the ribosome.
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Affiliation(s)
- Supriya Jindal
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Arnab Ghosh
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Amra Ismail
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Nishant Singh
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Anton A Komar
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
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Liao X, Zhao J, Liang S, Jin J, Li C, Xiao R, Li L, Guo M, Zhang G, Lin Y. Enhancing co-translational folding of heterologous protein by deleting non-essential ribosomal proteins in Pichia pastoris. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:38. [PMID: 30828383 PMCID: PMC6383220 DOI: 10.1186/s13068-019-1377-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 02/12/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Translational regulation played an important role in the correct folding of heterologous proteins to form bioactive conformations during biogenesis. Translational pausing coordinates protein translation and co-translational folding. Decelerating translation elongation speed has been shown to improve the soluble protein yield when expressing heterologous proteins in industrial expression hosts. However, rational redesign of translational pausing via synonymous mutations may not be feasible in many cases. Our goal was to develop a general and convenient strategy to improve heterologous protein synthesis in Pichia pastoris without mutating the expressed genes. RESULTS Here, a large-scale deletion library of ribosomal protein (RP) genes was constructed for heterologous protein expression in Pichia pastoris, and 59% (16/27) RP deletants have significantly increased heterologous protein yield. This is due to the delay of 60S subunit assembly by deleting non-essential ribosomal protein genes or 60S subunit processing factors, thus globally decreased the translation elongation speed and improved the co-translational folding, without perturbing the relative transcription level and translation initiation. CONCLUSION Global decrease in the translation elongation speed by RP deletion enhanced co-translational folding efficiency of nascent chains and decreased protein aggregates to improve heterologous protein yield. A potential expression platform for efficient pharmaceutical proteins and industrial enzymes production was provided without synonymous mutation.
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Affiliation(s)
- Xihao Liao
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
| | - Jing Zhao
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Shuli Liang
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
| | - Jingjie Jin
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Cheng Li
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
| | - Ruiming Xiao
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
| | - Lu Li
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
| | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai Institute of Biomanufacturing Technology & Collaborative Innovation Center, Shanghai, 200237 China
| | - Gong Zhang
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Ying Lin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006 China
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7
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Atomic resolution snapshot of Leishmania ribosome inhibition by the aminoglycoside paromomycin. Nat Commun 2017; 8:1589. [PMID: 29150609 PMCID: PMC5693986 DOI: 10.1038/s41467-017-01664-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/05/2017] [Indexed: 12/25/2022] Open
Abstract
Leishmania is a single-celled eukaryotic parasite afflicting millions of humans worldwide, with current therapies limited to a poor selection of drugs that mostly target elements in the parasite's cell envelope. Here we determined the atomic resolution electron cryo-microscopy (cryo-EM) structure of the Leishmania ribosome in complex with paromomycin (PAR), a highly potent compound recently approved for treatment of the fatal visceral leishmaniasis (VL). The structure reveals the mechanism by which the drug induces its deleterious effects on the parasite. We further show that PAR interferes with several aspects of cytosolic translation, thus highlighting the cytosolic rather than the mitochondrial ribosome as the primary drug target. The results also highlight unique as well as conserved elements in the PAR-binding pocket that can serve as hotspots for the development of novel therapeutics.
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8
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Mwangi HN, Wagacha P, Mathenge P, Sijenyi F, Mulaa F. Structure of the 40S ribosomal subunit of Plasmodium falciparum by homology and de novo modeling. Acta Pharm Sin B 2017; 7:97-105. [PMID: 28119814 PMCID: PMC5237758 DOI: 10.1016/j.apsb.2016.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/13/2016] [Accepted: 09/05/2016] [Indexed: 01/21/2023] Open
Abstract
Generation of three dimensional structures of macromolecules using in silico structural modeling technologies such as homology and de novo modeling has improved dramatically and increased the speed by which tertiary structures of organisms can be generated. This is especially the case if a homologous crystal structure is already available. High-resolution structures can be rapidly created using only their sequence information as input, a process that has the potential to increase the speed of scientific discovery. In this study, homology modeling and structure prediction tools such as RNA123 and SWISS–MODEL were used to generate the 40S ribosomal subunit from Plasmodium falciparum. This structure was modeled using the published crystal structure from Tetrahymena thermophila, a homologous eukaryote. In the absence of the Plasmodium falciparum 40S ribosomal crystal structure, the model accurately depicts a global topology, secondary and tertiary connections, and gives an overall root mean square deviation (RMSD) value of 3.9 Å relative to the template׳s crystal structure. Deviations are somewhat larger in areas with no homology between the templates. These results demonstrate that this approach has the power to identify motifs of interest in RNA and identify potential drug targets for macromolecules whose crystal structures are unknown. The results also show the utility of RNA homology modeling software for structure determination and lay the groundwork for applying this approach to larger and more complex eukaryotic ribosomes and other RNA-protein complexes. Structures generated from this study can be used in in silico screening experiments and lead to the determination of structures for targets/hit complexes.
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Ribosomal Protein Rps26 Influences 80S Ribosome Assembly in Saccharomyces cerevisiae. mSphere 2016; 1:mSphere00109-15. [PMID: 27303706 PMCID: PMC4863615 DOI: 10.1128/msphere.00109-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 02/04/2016] [Indexed: 11/20/2022] Open
Abstract
Rps26 is an essential protein of the eukaryotic small ribosomal subunit. Previous experiments demonstrated an interaction between the eukaryote-specific Y62–K70 segment of Rps26 and the 5′ untranslated region of mRNA. The data suggested a specific role of the Y62–K70 motif during translation initiation. Here, we report that single-site substitutions within the Y62–K70 peptide did not affect the growth of engineered yeast strains, arguing against its having a critical role during translation initiation via specific interactions with the 5′ untranslated region of mRNA molecules. Only the simultaneous replacement of five conserved residues within the Y62–K70 fragment or the replacement of the yeast protein with the human homolog resulted in growth defects and caused significant changes in polysome profiles. The results expand our knowledge of ribosomal protein function and suggest a role of Rps26 during ribosome assembly in yeast. The eukaryotic ribosome consists of a small (40S) and a large (60S) subunit. Rps26 is one of the essential ribosomal proteins of the 40S subunit and is encoded by two almost identical genes, RPS26a and RPS26b. Previous studies demonstrated that Rps26 interacts with the 5′ untranslated region of mRNA via the eukaryote-specific 62-YXXPKXYXK-70 (Y62–K70) motif. Those observations suggested that this peptide within Rps26 might play an important and specific role during translation initiation. By using alanine-scanning mutagenesis and engineered strains of the yeast Saccharomyces cerevisiae, we found that single amino acid substitutions within the Y62–K70 motif of Rps26 did not affect the in vivo function of the protein. In contrast, complete deletion of the Y62–K70 segment was lethal. The simultaneous replacement of five conserved residues within the Y62–K70 segment by alanines resulted in growth defects under stress conditions and produced distinct changes in polysome profiles that were indicative of the accumulation of free 60S subunits. Human Rps26 (Rps26-Hs), which displays significant homology with yeast Rps26, supported the growth of an S. cerevisiae Δrps26a Δrps26b strain. However, the Δrps26a Δrps26b double deletion strain expressing Rps26-Hs displayed substantial growth defects and an altered ratio of 40S/60S ribosomal subunits. The combined data strongly suggest that the eukaryote-specific motif within Rps26 does not play a specific role in translation initiation. Rather, the data indicate that Rps26 as a whole is necessary for proper assembly of the 40S subunit and the 80S ribosome in yeast. IMPORTANCE Rps26 is an essential protein of the eukaryotic small ribosomal subunit. Previous experiments demonstrated an interaction between the eukaryote-specific Y62–K70 segment of Rps26 and the 5′ untranslated region of mRNA. The data suggested a specific role of the Y62–K70 motif during translation initiation. Here, we report that single-site substitutions within the Y62–K70 peptide did not affect the growth of engineered yeast strains, arguing against its having a critical role during translation initiation via specific interactions with the 5′ untranslated region of mRNA molecules. Only the simultaneous replacement of five conserved residues within the Y62–K70 fragment or the replacement of the yeast protein with the human homolog resulted in growth defects and caused significant changes in polysome profiles. The results expand our knowledge of ribosomal protein function and suggest a role of Rps26 during ribosome assembly in yeast.
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10
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Wang S, You Z, Feng M, Che J, Zhang Y, Qian Q, Komatsu S, Zhong B. Analyses of the Molecular Mechanisms Associated with Silk Production in Silkworm by iTRAQ-Based Proteomics and RNA-Sequencing-Based Transcriptomics. J Proteome Res 2015; 15:15-28. [DOI: 10.1021/acs.jproteome.5b00821] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Shaohua Wang
- College
of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Zhengying You
- College
of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Mao Feng
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Jiaqian Che
- College
of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Yuyu Zhang
- College
of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Qiujie Qian
- College
of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Setsuko Komatsu
- National Institute of Crop Science, NARO, Tsukuba 305-8518, Japan
| | - Boxiong Zhong
- College
of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
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11
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Hernández-Ortega K, Garcia-Esparcia P, Gil L, Lucas JJ, Ferrer I. Altered Machinery of Protein Synthesis in Alzheimer's: From the Nucleolus to the Ribosome. Brain Pathol 2015; 26:593-605. [PMID: 26512942 DOI: 10.1111/bpa.12335] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 10/22/2015] [Indexed: 12/17/2022] Open
Abstract
Ribosomes and protein synthesis have been reported to be altered in the cerebral cortex at advanced stages of Alzheimer's disease (AD). Modifications in the hippocampus with disease progression have not been assessed. Sixty-seven cases including middle-aged (MA) and AD stages I-VI were analyzed. Nucleolar chaperones nucleolin, nucleophosmin and nucleoplasmin 3, and upstream binding transcription factor RNA polymerase I gene (UBTF) mRNAs are abnormally regulated and their protein levels reduced in AD. Histone modifications dimethylated histone H3K9 (H3K9me2) and acetylated histone H3K12 (H3K12ac) are decreased in CA1. Nuclear tau declines in CA1 and dentate gyrus (DG), and practically disappears in neurons with neurofibrillary tangles. Subunit 28 ribosomal RNA (28S rRNA) expression is altered in CA1 and DG in AD. Several genes encoding ribosomal proteins are abnormally regulated and protein levels of translation initiation factors eIF2α, eIF3η and eIF5, and elongation factor eEF2, are altered in the CA1 region in AD. These findings show alterations in the protein synthesis machinery in AD involving the nucleolus, nucleus and ribosomes in the hippocampus in AD some of them starting at first stages (I-II) preceding neuron loss. These changes may lie behind reduced numbers of dendritic branches and reduced synapses of CA1 and DG neurons which cause hippocampal atrophy.
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Affiliation(s)
- Karina Hernández-Ortega
- Institute of Neuropathology, Service of Pathologic Anatomy, IDIBELL-Bellvitge University Hospital, University of Barcelona, Hospitalet de Llobregat, Spain.,Neuropathology, CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), Madrid, Spain
| | - Paula Garcia-Esparcia
- Institute of Neuropathology, Service of Pathologic Anatomy, IDIBELL-Bellvitge University Hospital, University of Barcelona, Hospitalet de Llobregat, Spain.,Neuropathology, CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), Madrid, Spain
| | - Laura Gil
- Department of Genetics, Medical School, Alfonso X el Sabio University (UAX), Villanueva de la Cañada; Centro de Investigaciones Biologicas (CIB), CSIC, Madrid, Spain
| | - José J Lucas
- Neuropathology, CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), Madrid, Spain.,Department of Molecular Biology, Center for Molecular Biology "Severo Ochoa" (CBMSO) CSIC/UAM, Madrid, 28049, Spain
| | - Isidre Ferrer
- Institute of Neuropathology, Service of Pathologic Anatomy, IDIBELL-Bellvitge University Hospital, University of Barcelona, Hospitalet de Llobregat, Spain.,Neuropathology, CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), Madrid, Spain
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Garcia-Esparcia P, Hernández-Ortega K, Koneti A, Gil L, Delgado-Morales R, Castaño E, Carmona M, Ferrer I. Altered machinery of protein synthesis is region- and stage-dependent and is associated with α-synuclein oligomers in Parkinson's disease. Acta Neuropathol Commun 2015; 3:76. [PMID: 26621506 PMCID: PMC4666041 DOI: 10.1186/s40478-015-0257-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 11/14/2015] [Indexed: 01/17/2023] Open
Abstract
INTRODUCTION Parkinson's disease (PD) is characterized by the accumulation of abnormal α-synuclein in selected regions of the brain following a gradient of severity with disease progression. Whether this is accompanied by globally altered protein synthesis is poorly documented. The present study was carried out in PD stages 1-6 of Braak and middle-aged (MA) individuals without alterations in brain in the substantia nigra, frontal cortex area 8, angular gyrus, precuneus and putamen. RESULTS Reduced mRNA expression of nucleolar proteins nucleolin (NCL), nucleophosmin (NPM1), nucleoplasmin 3 (NPM3) and upstream binding transcription factor (UBF), decreased NPM1 but not NPM3 nucleolar protein immunostaining in remaining neurons; diminished 18S rRNA, 28S rRNA; reduced expression of several mRNAs encoding ribosomal protein (RP) subunits; and altered protein levels of initiation factor eIF3 and elongation factor eEF2 of protein synthesis was found in the substantia nigra in PD along with disease progression. Although many of these changes can be related to neuron loss in the substantia nigra, selective alteration of certain factors indicates variable degree of vulnerability of mRNAs, rRNAs and proteins in degenerating sustantia nigra. NPM1 mRNA and 18S rRNA was increased in the frontal cortex area 8 at stage 5-6; modifications were less marked and region-dependent in the angular gyrus and precuneus. Several RPs were abnormally regulated in the frontal cortex area 8 and precuneus, but only one RP in the angular gyrus, in PD. Altered levels of eIF3 and eIF1, and decrease eEF1A and eEF2 protein levels were observed in the frontal cortex in PD. No modifications were found in the putamen at any time of the study except transient modifications in 28S rRNA and only one RP mRNA at stages 5-6. These observations further indicate marked region-dependent and stage-dependent alterations in the cerebral cortex in PD. Altered solubility and α-synuclein oligomer formation, assessed in total homogenate fractions blotted with anti-α-synuclein oligomer-specific antibody, was demonstrated in the substantia nigra and frontal cortex, but not in the putamen, in PD. Dramatic increase in α-synuclein oligomers was also seen in fluorescent-activated cell sorter (FACS)-isolated nuclei in the frontal cortex in PD. CONCLUSIONS Altered machinery of protein synthesis is altered in the substantia nigra and cerebral cortex in PD being the frontal cortex area 8 more affected than the angular gyrus and precuneus; in contrast, pathways of protein synthesis are apparently preserved in the putamen. This is associated with the presence of α-synuclein oligomeric species in total homogenates; substantia nigra and frontal cortex are enriched, albeit with different band patterns, in α-synuclein oligomeric species, whereas α-synuclein oligomers are not detected in the putamen.
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Affiliation(s)
- Paula Garcia-Esparcia
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
| | - Karina Hernández-Ortega
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
| | - Anusha Koneti
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
| | - Laura Gil
- Department of Genetics, Medical School, Alfonso X el Sabio University, Villanueva de la Cañada, Madrid, Spain
| | - Raul Delgado-Morales
- Cancer Epigenetics and Biology Program, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Ester Castaño
- Biology-Bellvitge Unit, Scientific and Technological Centers-University of Barcelona (CCiTUB), Hospitalet de Llobregat, Barcelona, Spain
| | - Margarita Carmona
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
| | - Isidre Ferrer
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain.
- Institute of Neuropathology, Service of Pathologic Anatomy, Bellvitge University Hospital, carrer Feixa Llarga s/n, 08907, Hospitalet de Llobregat, Spain.
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Efficient and dynamic nuclear localization of green fluorescent protein via RNA binding. Biochem Biophys Res Commun 2015; 463:401-6. [DOI: 10.1016/j.bbrc.2015.05.084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 05/27/2015] [Indexed: 01/15/2023]
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de Las Heras-Rubio A, Perucho L, Paciucci R, Vilardell J, LLeonart ME. Ribosomal proteins as novel players in tumorigenesis. Cancer Metastasis Rev 2015; 33:115-41. [PMID: 24375388 DOI: 10.1007/s10555-013-9460-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ribosome biogenesis is the most demanding energetic and metabolic expenditure of the cell. The nucleolus, a nuclear compartment, coordinates rRNA transcription, maturation, and assembly into ribosome subunits. The transcription process is highly coordinated with ribosome biogenesis. In this context, ribosomal proteins (RPs) play a crucial role. In the last decade, an increasing number of studies have associated RPs with extraribosomal functions related to proliferation. Importantly, the expression of RPs appears to be deregulated in several human disorders due, at least in part, to genetic mutations. Although the deregulation of RPs in human malignancies is commonly observed, a more complex mechanism is believed to be involved, favoring the tumorigenic process, its progression and metastasis. This review explores the roles of the most frequently mutated oncogenes and tumor suppressor genes in human cancer that modulate ribosome biogenesis, including their interaction with RPs. In this regard, we propose a new focus for novel therapies.
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Affiliation(s)
- A de Las Heras-Rubio
- Oncology and Pathology Group, Institut de Recerca Hospital Vall d'Hebron, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain
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Sun J, Li C, Wang S. The Up-Regulation of Ribosomal Proteins Further Regulates Protein Expression Profile in Female Schistosoma japonicum after Pairing. PLoS One 2015; 10:e0129626. [PMID: 26070205 PMCID: PMC4466501 DOI: 10.1371/journal.pone.0129626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 05/11/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Pairing of Schistosoma males and females leads to and maintains female sexual maturation. However, the mechanism by which pairing facilitates sexual maturation of females is not clear. An increasing body of evidence suggests that ribosomal proteins have regulatory rather than constitutive roles in protein translation. METHODOLOGY/PRINCIPAL FINDINGS To investigate the effect of ribosome regulation on female sex maturation, Solexa and iTRAQ techniques were used to analyze the relationship between ribosomal gene or protein expression and sexual development of Schistosoma females. In the present study, considerably higher number of ribosomal genes or proteins were found to be differentially expressed in paired 23-day-old females. Moreover, mature female-specific proteins associated with egg production, such as ferritin-1 heavy chain and superoxide dismutase, were selectively highly expressed in paired females, rather than higher level of protein synthesis of all transcripts compared with those in unpaired 23-day-old females. Furthermore, other developmental stages were utilized to investigate different expression pattern of ribosomal proteins in females by analysing 18-day-old female schistosomula from single- or double-sex infections to determine the relationship between ribosomal protein expression pattern and development. Results showed that undeveloped 18-day-old females from single- and double-sex infections, as well as 23-day-old unpaired females, possessed similar ribosomal protein expression patterns, which were distinct from those in 23-day-old paired females. CONCLUSIONS/SIGNIFICANCE Our findings reveal that the pairing of females and males triggers a specialized ribosomal protein expression profile which further regulates the protein profile for sexual maturation in Schistosoma japonicum, based on its gene expression profile.
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Affiliation(s)
- Jun Sun
- Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Chen Li
- Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Suwen Wang
- Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, People's Republic of China
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Kenney SP, Meng XJ. Identification and fine mapping of nuclear and nucleolar localization signals within the human ribosomal protein S17. PLoS One 2015; 10:e0124396. [PMID: 25853866 PMCID: PMC4390217 DOI: 10.1371/journal.pone.0124396] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/13/2015] [Indexed: 01/29/2023] Open
Abstract
Human ribosomal protein S17 (RPS17) is mutated in Diamond-Blackfan Anemia (DBA), a bone marrow disorder that fails to produce sufficient red blood cells leading to anemia. Recently, an RPS17 protein sequence was also found to be naturally inserted in the genome of hepatitis E virus (HEV) from patients chronically-infected by HEV. The role of RPS17 in HEV replication and pathogenesis remains unknown due to the lack of knowledge about how RPS17 functions at a molecular level. Understanding the biological function of RPS17 is critical for elucidating its role in virus infection and DBA disease processes. In this study we probed the subcellular distribution of normal and mutant RPS17 proteins in a human liver cell line (Huh7). RPS17 was primarily detected within the nucleus, and more specifically within the nucleoli. Using a transient expression system in which RPS17 or truncations were expressed as fusions with enhanced yellow fluorescent protein (eYFP), we were able to identify and map, for the first time, two separate nuclear localization signals (NLSs), one to the first 13 amino acids of the amino-terminus of RPS17 and the other within amino acids 30-60. Additionally, we mapped amino acid sequences required for nucleolar accumulation of RPS17 to amino acids 60-70. Amino acids 60-70 possess a di-RG motif that may be necessary for nucleolar retention of RPS17. The results from this study enhance our knowledge of RSP17 and will facilitate future mechanistic studies about the roles of RSP17 in hepatitis E and DBA disease processes.
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Affiliation(s)
- Scott P. Kenney
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, United States of America
| | - Xiang-Jin Meng
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, United States of America
- * E-mail:
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Ghosh A, Komar AA. Eukaryote-specific extensions in ribosomal proteins of the small subunit: Structure and function. ACTA ACUST UNITED AC 2015; 3:e999576. [PMID: 26779416 DOI: 10.1080/21690731.2014.999576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/03/2014] [Accepted: 12/12/2014] [Indexed: 01/05/2023]
Abstract
High-resolution structures of yeast ribosomes have improved our understanding of the architecture and organization of eukaryotic rRNA and proteins, as well as eukaryote-specific extensions present in some conserved ribosomal proteins. Despite this progress, assignment of specific functions to individual proteins and/or eukaryote-specific protein extensions remains challenging. It has been suggested that eukaryote-specific extensions of conserved proteins from the small ribosomal subunit may facilitate eukaryote-specific reactions in the initiation phase of protein synthesis. This review summarizes emerging data describing the structural and functional significance of eukaryote-specific extensions of conserved small ribosomal subunit proteins, particularly their possible roles in recruitment and spatial organization of eukaryote-specific initiation factors.
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Affiliation(s)
- Arnab Ghosh
- Center for Gene Regulation in Health and Disease; Department of Biological, Geological and Environmental Sciences; Cleveland State University ; Cleveland, OH USA
| | - Anton A Komar
- Center for Gene Regulation in Health and Disease; Department of Biological, Geological and Environmental Sciences; Cleveland State University ; Cleveland, OH USA
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Graifer D, Karpova G. Roles of ribosomal proteins in the functioning of translational machinery of eukaryotes. Biochimie 2015; 109:1-17. [DOI: 10.1016/j.biochi.2014.11.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 11/18/2014] [Indexed: 11/16/2022]
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The lysine residues within the human ribosomal protein S17 sequence naturally inserted into the viral nonstructural protein of a unique strain of hepatitis E virus are important for enhanced virus replication. J Virol 2015; 89:3793-803. [PMID: 25609799 DOI: 10.1128/jvi.03582-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
UNLABELLED Hepatitis E virus (HEV) is an important but extremely understudied human pathogen. Due largely to the lack of an efficient cell culture system for HEV, the molecular mechanisms of HEV replication and pathogenesis are poorly understood. Recently, a unique genotype 3 strain of HEV recovered from a chronically infected patient was adapted for growth in HepG2C3A human hepatoma cells. The adaptation of the Kernow C-1 P6 HEV to propagate in HepG2C3A cells selected for a rare virus recombinant that contains an insertion of a 171-nucleotide sequence encoding amino acids 21 to 76 of the human ribosomal protein S17 (RPS17) within the hypervariable region (HVR) of the HEV ORF1 protein. When the RPS17 insertion was placed into a strain of genotype 1 HEV which infects only humans, it expanded the host range of the virus, allowing it to infect cell lines from multiple animal species, including cow, dog, cat, chicken, and hamster. In this study, we utilized forward and reverse genetics to attempt to define which aspects of the RPS17 insertion allow for the ability of the Kernow C-1 P6 HEV to adapt in cell culture and allow for expanded host tropism. We demonstrate that the RPS17 sequence insertion in HEV bestows novel nuclear/nucleolar trafficking capabilities to the ORF1 protein of Kernow P6 HEV and that lysine residues within the RPS17 insertion, but not nuclear localization of the ORF1 protein, correlate with the enhanced replication of the HEV Kernow C-1 P6 strain. The results from this study have important implications for understanding the mechanism of cross-species infection and replication of HEV. IMPORTANCE HEV is an important pathogen worldwide. The virus causes high mortality (up to 30%) in pregnant women and has been recognized to cause chronic hepatitis in immunocompromised populations. The life cycle of HEV has been understudied due to a lack of sufficient cell culture systems in which to propagate the virus. Recently, insertions and rearrangements of the hypervariable region (HVR) within the HEV genome, allowing for cell culture adaptation and expansion of the host range, have been reported. We utilized these cell culture-adapted HEV strains to assess how the HVR may be involved in virus replication and host range. We provide evidence that insertion of the RPS17 sequence in HEV likely confers nuclear trafficking capabilities to the nonstructural protein of the virus and that lysine residues within the RPS17 insertion are important for enhanced replication of the virus. These data will help to elucidate the mechanism of cross-species infection of HEV in the future.
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Morgado-Palacin L, Llanos S, Urbano-Cuadrado M, Blanco-Aparicio C, Megias D, Pastor J, Serrano M. Non-genotoxic activation of p53 through the RPL11-dependent ribosomal stress pathway. Carcinogenesis 2014; 35:2822-30. [PMID: 25344835 DOI: 10.1093/carcin/bgu220] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Nucleolar disruption has recently emerged as a relevant means to activate p53 through inhibition of HDM2 by ribosome-free RPL11. Most drugs that induce nucleolar disruption also possess important genotoxic activity, which can have lasting mutagenic effects. Therefore, it is of interest to identify compounds that selectively produce nucleolar disruption in the absence of DNA damage. Here, we have performed a high-throughput screening to search for nucleolar disruptors. We have identified an acridine derivative (PubChem CID-765471) previously known for its capacity to activate p53 independently of DNA damage, although the molecular mechanism underlying p53 activation had remained uncharacterized. We report that CID-765471 produces nucleolar disruption by inhibiting ribosomal DNA transcription in a process that includes the selective degradation of the RPA194 subunit of RNA polymerase I. Following nucleolar disruption, CID-765471 activates p53 through the RPL11/HDM2 pathway in the absence of detectable DNA damage. In a secondary screening of compounds approved for medical use, we identify two additional acridine derivatives, aminacrine and ethacridine, that operate in a similar manner as CID-765471. These findings provide the basis for non-genotoxic chemotherapeutic approaches that selectively target the nucleolus.
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Affiliation(s)
- Lucia Morgado-Palacin
- Tumour Suppression Group, Experimental Therapeutics Program and Confocal Microscopy Unit, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
| | - Susana Llanos
- Tumour Suppression Group, Experimental Therapeutics Program and Confocal Microscopy Unit, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
| | | | | | - Diego Megias
- Confocal Microscopy Unit, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
| | | | - Manuel Serrano
- Tumour Suppression Group, Experimental Therapeutics Program and Confocal Microscopy Unit, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
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Lyar, a cell growth-regulating zinc finger protein, was identified to be associated with cytoplasmic ribosomes in male germ and cancer cells. Mol Cell Biochem 2014; 395:221-9. [PMID: 24990247 DOI: 10.1007/s11010-014-2128-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 06/17/2014] [Indexed: 12/31/2022]
Abstract
Translational control is a basic mechanism for gene regulation in cells and important for tissue growth and development in mammals. Deregulation of the mechanism thus causes diseases such as cancer. Considering the importance of the ribosome as a factory of polypeptide synthesis, some new factors have been expected to be associated with the ribosome and involved in translational control. Our proteomic survey for these factors identified a zinc finger protein, Lyar, in cytoplasmic ribosomes of the rodent testis. Subcellular fractionation of the testis provided data supporting association of Lyar with ribosomes. Lyar was then suggested to be included in the 60S large subunit, but not in polysomes, by ultracentrifugation of testicular ribosomes. While analysis of tissue distribution of Lyar has indicated its testis-predominant expression, Lyar mRNA was expressed in the cancer cells originated from tissues other than testis, and Lyar promoted proliferation of NIH-3T3 cells. Furthermore, translation was increased by Lyar in vitro, pointing out the first experimental link between this protein and translation. Taken together, Lyar seems to be a new player in translational control and a potential target for cancer therapy.
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Piir K, Tamm T, Kisly I, Tammsalu T, Remme J. Stepwise splitting of ribosomal proteins from yeast ribosomes by LiCl. PLoS One 2014; 9:e101561. [PMID: 24991888 PMCID: PMC4081664 DOI: 10.1371/journal.pone.0101561] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/08/2014] [Indexed: 11/19/2022] Open
Abstract
Structural studies have revealed that the core of the ribosome structure is conserved among ribosomes of all kingdoms. Kingdom-specific ribosomal proteins (r-proteins) are located in peripheral parts of the ribosome. In this work, the interactions between rRNA and r-proteins of eukaryote Saccharomyces cerevisiae ribosome were investigated applying LiCl induced splitting and quantitative mass spectrometry. R-proteins were divided into four groups according to their binding properties to the rRNA. Most yeast r-proteins are removed from rRNA by 0.5-1 M LiCl. Eukaryote-specific r-proteins are among the first to dissociate. The majority of the strong binders are known to be required for the early ribosome assembly events. As compared to the bacterial ribosome, yeast r-proteins are dissociated from rRNA at lower ionic strength. Our results demonstrate that the nature of protein-RNA interactions in the ribosome is not conserved between different kingdoms.
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Affiliation(s)
- Kerli Piir
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Tiina Tamm
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Ivan Kisly
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Triin Tammsalu
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Jaanus Remme
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail:
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Shi Y, Liu X, Li R, Gao Y, Xu Z, Zhang B, Zhou Y. Retention of OsNMD3 in the cytoplasm disturbs protein synthesis efficiency and affects plant development in rice. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3055-69. [PMID: 24723395 PMCID: PMC4071826 DOI: 10.1093/jxb/eru150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ribosome is the basic machinery for translation, and biogenesis of ribosomes involves many coordinated events. However, knowledge about ribosomal dynamics in higher plants is very limited. This study chose a highly conserved trans-factor, the 60S ribosomal subunit nuclear export adaptor NMD3, to characterize the mechanism of ribosome biogenesis in the monocot plant Oryza sativa (rice). O. sativa NMD3 (OsNMD3) shares all the common motifs and shuttles between the nucleus and cytoplasm via CRM1/XPO1. A dominant negative form of OsNMD3 with a truncated nuclear localization sequence (OsNMD3(ΔNLS)) was retained in the cytoplasm, consequently interfering with the release of OsNMD3 from pre-60S particles and disturbing the assembly of ribosome subunits. Analyses of the transactivation activity and cellulose biosynthesis level revealed low protein synthesis efficiency in the transgenic plants compared with the wild-type plants. Pharmaceutical treatments demonstrated structural alterations in ribosomes in the transgenic plants. Moreover, global expression profiles of the wild-type and transgenic plants were investigated using the Illumina RNA sequencing approach. These expression profiles suggested that overexpression of OsNMD3(ΔNLS) affected ribosome biogenesis and certain basic pathways, leading to pleiotropic abnormalities in plant growth. Taken together, these results strongly suggest that OsNMD3 is important for ribosome assembly and the maintenance of normal protein synthesis efficiency.
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Affiliation(s)
- Yanyun Shi
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiangling Liu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Rui Li
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yaping Gao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zuopeng Xu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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Ghosh A, Jindal S, Bentley AA, Hinnebusch AG, Komar AA. Rps5-Rps16 communication is essential for efficient translation initiation in yeast S. cerevisiae. Nucleic Acids Res 2014; 42:8537-55. [PMID: 24948608 PMCID: PMC4117775 DOI: 10.1093/nar/gku550] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Conserved ribosomal proteins frequently harbor additional segments in eukaryotes not found in bacteria, which could facilitate eukaryotic-specific reactions in the initiation phase of protein synthesis. Here we provide evidence showing that truncation of the N-terminal domain (NTD) of yeast Rps5 (absent in bacterial ortholog S7) impairs translation initiation, cell growth and induction of GCN4 mRNA translation in a manner suggesting incomplete assembly of 48S preinitiation complexes (PICs) at upstream AUG codons in GCN4 mRNA. Rps5 mutations evoke accumulation of factors on native 40S subunits normally released on conversion of 48S PICs to 80S initiation complexes (ICs) and this abnormality and related phenotypes are mitigated by the SUI5 variant of eIF5. Remarkably, similar effects are observed by substitution of Lys45 in the Rps5-NTD, involved in contact with Rps16, and by eliminating the last two residues of the C-terminal tail (CTT) of Rps16, believed to contact initiator tRNA base-paired to AUG in the P site. We propose that Rps5-NTD-Rps16-NTD interaction modulates Rps16-CTT association with Met-tRNAi (Met) to promote a functional 48S PIC.
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Affiliation(s)
- Arnab Ghosh
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Supriya Jindal
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Amber A Bentley
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Alan G Hinnebusch
- Laboratory of Gene Regulation and Development, Eunice K. Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anton A Komar
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
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25
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Regulation of protein translation and c-Jun expression by prostate tumor overexpressed 1. Oncogene 2013; 33:1124-34. [PMID: 23455324 DOI: 10.1038/onc.2013.51] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 12/17/2012] [Accepted: 01/11/2013] [Indexed: 12/18/2022]
Abstract
Prostate tumor overexpressed-1 (PTOV1), a modulator of the Mediator transcriptional regulatory complex, is expressed at high levels in prostate cancer and other neoplasias in association with a more aggressive disease. Here we show that PTOV1 interacts directly with receptor of activated protein C kinase 1 (RACK1), a regulator of protein kinase C and Jun signaling and also a component of the 40S ribosome. Consistent with this interaction, PTOV1 was associated with ribosomes and its overexpression promoted global protein synthesis in prostate cancer cells and COS-7 fibroblasts in a mTORC1-dependent manner. Transfection of ectopic PTOV1 enhanced the expression of c-Jun protein without affecting the levels of c-Jun or RACK1 mRNA. Conversely, knockdown of PTOV1 caused significant declines in global protein synthesis and c-Jun protein levels. High levels of PTOV1 stimulated the motility and invasiveness of prostate cancer cells, which required c-Jun, whereas knockdown of PTOV1 strongly inhibited the tumorigenic and metastatic potentials of PC-3 prostate cancer cells. In human prostate cancer samples, the expression of high levels of PTOV1 in primary and metastatic tumors was significantly associated with increased nuclear localization of active c-Jun. These results unveil new functions of PTOV1 in the regulation of protein translation and in the progression of prostate cancer to an invasive and metastatic disease.
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26
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Gamalinda M, Jakovljevic J, Babiano R, Talkish J, de la Cruz J, Woolford JL. Yeast polypeptide exit tunnel ribosomal proteins L17, L35 and L37 are necessary to recruit late-assembling factors required for 27SB pre-rRNA processing. Nucleic Acids Res 2012; 41:1965-83. [PMID: 23268442 PMCID: PMC3561946 DOI: 10.1093/nar/gks1272] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Ribosome synthesis involves the coordinated folding and processing of pre-rRNAs with assembly of ribosomal proteins. In eukaryotes, these events are facilitated by trans-acting factors that propel ribosome maturation from the nucleolus to the cytoplasm. However, there is a gap in understanding how ribosomal proteins configure pre-ribosomes in vivo to enable processing to occur. Here, we have examined the role of adjacent yeast r-proteins L17, L35 and L37 in folding and processing of pre-rRNAs, and binding of other proteins within assembling ribosomes. These three essential ribosomal proteins, which surround the polypeptide exit tunnel, are required for 60S subunit formation as a consequence of their role in removal of the ITS2 spacer from 27SB pre-rRNA. L17-, L35- and L37-depleted cells exhibit turnover of aberrant pre-60S assembly intermediates. Although the structure of ITS2 does not appear to be grossly affected in their absence, these three ribosomal proteins are necessary for efficient recruitment of factors required for 27SB pre-rRNA processing, namely, Nsa2 and Nog2, which associate with pre-60S ribosomal particles containing 27SB pre-rRNAs. Altogether, these data support that L17, L35 and L37 are specifically required for a recruiting step immediately preceding removal of ITS2.
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Affiliation(s)
- Michael Gamalinda
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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27
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Graifer D, Karpova G. Structural and functional topography of the human ribosome. Acta Biochim Biophys Sin (Shanghai) 2012; 44:281-99. [PMID: 22257731 DOI: 10.1093/abbs/gmr118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
This review covers data on the structural organization of functional sites in the human ribosome, namely, the messenger RNA binding center, the binding site of the hepatitis C virus RNA internal ribosome entry site, and the peptidyl transferase center. The data summarized here have been obtained primarily by means of a site-directed cross-linking approach with application of the analogs of the respective ribosomal ligands bearing cross-linkers at the designed positions. These data are discussed taking into consideration available structural data on ribosomes from various kingdoms obtained with the use of cryo-electron microscopy, X-ray crystallography, and other approaches.
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Affiliation(s)
- Dmitri Graifer
- Laboratory of Ribosome Structure and Functions, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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28
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Chen X, Wu CW, Zhong SP, Zeng FR, Zhang JS, Wang J, Niu SF. Molecular characterization and structure analysis of RPL10/QM-like protein from the red drum Sciaenops ocellatus (Sciaenidae). GENETICS AND MOLECULAR RESEARCH 2011; 10:576-87. [PMID: 21491368 DOI: 10.4238/vol10-2gmr1134] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The QM-like gene encodes a ribosomal protein L10. Besides housekeeping roles in protein synthesis, QM-like proteins have multiple extraribosomal functions during cell growth, cell differentiation and apoptosis. We obtained the full-length cDNA of QM-like protein (designated as SoQM) from the salt water game fish Sciaenops ocellatus, using RACE-PCR. The sequence consists of 740 bp, encoding 215-amino acid residues with 24.60 kDa. The AA sequence of the SoQM protein contains a series of functional motifs that belong to the QM family signature, which is conserved among different species. The SoQM gene contains five introns and six exons. The expression pattern of SoQM as determined by RT-PCR indicated that SoQM mRNA was expressed in all tissues tested, including brain, gill, head-kidney, intestine, stomach, heart, spleen, blood, muscle, and gonads. The phylogenetic tree constructed with MEGA 4.0 showed that SoQM clusters together with that of other fish. It was found that the sequences of the SoQM gene are highly conserved, suggesting the fundamental and critical functions of SoQM in S. ocellatus. The three-dimensional structure of the SoQM protein core domain (4~169) was predicted by the Swiss-Model program. Compared with QM proteins in other species, the main structure of SoQM protein was conserved, while the C-terminal domain was different from other QM-like proteins. Prediction of the three-dimensional structure of SoQM would provide valuable insight into the molecular basis of protein function, allowing an effective design of experiments, such as site-directed mutagenesis, studies of disease-related mutations or structure-based design of specific inhibitors.
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Affiliation(s)
- X Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
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29
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Are ribosomal proteins present at transcription sites on or off ribosomal subunits? Biochem Soc Trans 2011; 38:1543-7. [PMID: 21118123 DOI: 10.1042/bst0381543] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
RPs (ribosomal proteins) are main components of the ribosome having essential functions in its biogenesis, function and structural integrity. Although most of the RP molecules are in the cytoplasm, being incorporated into translating ribosomes, some RPs have non-ribosomal functions when they are off ribosomal subunits. Notably, in eukaryotes, RPs are also present at transcription sites and some of these proteins have a function in transcription and pre-mRNA processing of specific genes. Although the consensus is that the proteins found at these sites are isolated RPs not assembled into ribosomal subunits, it has been proposed that ribosomal subunits might also be present. In the present paper, we review the available evidence for RPs at transcription sites and conclude that ribosomal subunits might be present, but additional studies will be required to solve this important issue.
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30
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Muhs M, Yamamoto H, Ismer J, Takaku H, Nashimoto M, Uchiumi T, Nakashima N, Mielke T, Hildebrand PW, Nierhaus KH, Spahn CMT. Structural basis for the binding of IRES RNAs to the head of the ribosomal 40S subunit. Nucleic Acids Res 2011; 39:5264-75. [PMID: 21378123 PMCID: PMC3130280 DOI: 10.1093/nar/gkr114] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Some viruses exploit internal initiation for their propagation in the host cell. This type of initiation is facilitated by structured elements (internal ribosome entry site, IRES) upstream of the initiator AUG and requires only a reduced number of canonical initiation factors. An important example are IRES of the virus family Dicistroviridae that bind to the inter-subunit side of the small ribosomal 40S subunit and lead to the formation of elongation-competent 80S ribosomes without the help of any initiation factor. Here, we present a comprehensive functional and structural analysis of eukaryotic-specific ribosomal protein rpS25 in the context of this type of initiation and propose a structural model explaining the essential involvement of rpS25 for hijacking the ribosome.
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Affiliation(s)
- Margarita Muhs
- Institut für Medizinische Physik und Biophysik, Charite - Universitätsmedizin Berlin, Ziegelstrasse 5-9, 10117-Berlin, Germany
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31
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Gilbert WV. Functional specialization of ribosomes? Trends Biochem Sci 2011; 36:127-32. [PMID: 21242088 DOI: 10.1016/j.tibs.2010.12.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 10/29/2010] [Accepted: 12/08/2010] [Indexed: 10/18/2022]
Abstract
Ribosomes are highly conserved macromolecular machines that are responsible for protein synthesis in all living organisms. Work published in the past year has shown that changes to the ribosome core can affect the mechanism of translation initiation that is favored in the cell, which potentially leads to specific changes in the relative efficiencies with which different proteins are made. Here, I examine recent data from expression and proteomic studies that suggest that cells make slightly different ribosomes under different growth conditions, and discuss genetic evidence that such differences are functional. In particular, I argue that eukaryotic cells probably produce ribosomes that lack one or more core ribosomal proteins (RPs) under some conditions, and that core RPs contribute differentially to translation of distinct subpopulations of mRNAs.
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Affiliation(s)
- Wendy V Gilbert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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32
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Paris DBBP, Kuijk EW, Roelen BAJ, Stout TAE. Establishing reference genes for use in real-time quantitative PCR analysis of early equine embryos. Reprod Fertil Dev 2011; 23:353-63. [DOI: 10.1071/rd10039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Accepted: 08/14/2010] [Indexed: 12/19/2022] Open
Abstract
Real-time quantitative PCR (qPCR) is invaluable for investigating changes in gene expression during early development, since it can be performed on the limited quantities of mRNA contained in individual embryos. However, the reliability of this method depends on the use of validated stably expressed reference genes for accurate data normalisation. The aim of the present study was to identify and validate a set of reference genes suitable for studying gene expression during equine embryo development. The stable expression of four carefully selected reference genes and one developmentally regulated gene was examined by qPCR in equine in vivo embryos from morula to expanded blastocyst stage. SRP14, RPL4 and PGK1 were identified by geNorm analysis as stably expressed reference genes suitable for data normalisation. RPL13A expression was less stable and changed significantly during the period of development examined, rendering it unsuitable as a reference gene. As anticipated, CDX2 expression increased significantly during embryo development, supporting its possible role in trophectoderm specification in the horse. In summary, it was demonstrated that evidence-based selection of potential reference genes can reduce the number needed to validate stable expression in an experimental system; this is particularly useful when dealing with tissues that yield small amounts of mRNA. SRP14, RPL4 and PGK1 are stable reference genes suitable for normalising expression for genes of interest during in vivo morula to expanded blastocyst development of horse embryos.
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33
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Rabl J, Leibundgut M, Ataide SF, Haag A, Ban N. Crystal structure of the eukaryotic 40S ribosomal subunit in complex with initiation factor 1. Science 2010; 331:730-6. [PMID: 21205638 DOI: 10.1126/science.1198308] [Citation(s) in RCA: 366] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Eukaryotic ribosomes are substantially larger and more complex than their bacterial counterparts. Although their core function is conserved, bacterial and eukaryotic protein synthesis differ considerably at the level of initiation. The eukaryotic small ribosomal subunit (40S) plays a central role in this process; it binds initiation factors that facilitate scanning of messenger RNAs and initiation of protein synthesis. We have determined the crystal structure of the Tetrahymena thermophila 40S ribosomal subunit in complex with eukaryotic initiation factor 1 (eIF1) at a resolution of 3.9 angstroms. The structure reveals the fold of the entire 18S ribosomal RNA and of all ribosomal proteins of the 40S subunit, and defines the interactions with eIF1. It provides insights into the eukaryotic-specific aspects of protein synthesis, including the function of eIF1 as well as signaling and regulation mediated by the ribosomal proteins RACK1 and rpS6e.
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Affiliation(s)
- Julius Rabl
- Institute of Molecular Biology and Biophysics, ETH Zürich, Schafmattstrasse 20, 8093 Zürich, Switzerland
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34
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N(α)-Acetylation of yeast ribosomal proteins and its effect on protein synthesis. J Proteomics 2010; 74:431-41. [PMID: 21184851 DOI: 10.1016/j.jprot.2010.12.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 01/18/2023]
Abstract
N(α)-Acetyltransferases (NATs) cause the N(α)-acetylation of the majority of eukaryotic proteins during their translation, although the functions of this modification have been largely unexplored. In yeast (Saccharomyces cerevisiae), four NATs have been identified: NatA, NatB, NatC, and NatD. In this study, the N(α)-acetylation status of ribosomal protein was analyzed using NAT mutants combined with two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry (MS). A total of 60 ribosomal proteins were identified, of which 17 were N(α)-acetylated by NatA, and two by NatB. The N(α)-acetylation of two of these, S17 and L23, by NatA was not previously observed. Furthermore, we tested the effect of ribosomal protein N(α)-acetylation on protein synthesis using the purified ribosomes from each NAT mutant. It was found that the protein synthesis activities of ribosomes from NatA and NatB mutants were decreased by 27% and 23%, respectively, as compared to that of the normal strain. Furthermore, we have shown that ribosomal protein N(α)-acetylation by NatA influences translational fidelity in the presence of paromomycin. These results suggest that ribosomal protein N(α)-acetylation is necessary to maintain the ribosome's protein synthesis function.
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35
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Zeidan Q, Wang Z, De Maio A, Hart GW. O-GlcNAc cycling enzymes associate with the translational machinery and modify core ribosomal proteins. Mol Biol Cell 2010; 21:1922-36. [PMID: 20410138 PMCID: PMC2883937 DOI: 10.1091/mbc.e09-11-0941] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
At least 20 core ribosome proteins are modified by O-GlcNAc. O-GlcNAcase is localized to the nucleolus and O-GlcNAc transferase is excluded from the nucleolus. Both enzymes associate with active polysomes. Overexpression of OGT disrupts ribosomal subunit homeostasis. Data suggest that O-GlcNAc regulates translation and ribosome biogenesis. Protein synthesis is globally regulated through posttranslational modifications of initiation and elongation factors. Recent high-throughput studies have identified translation factors and ribosomal proteins (RPs) as substrates for the O-GlcNAc modification. Here we determine the extent and abundance of O-GlcNAcylated proteins in translational preparations. O-GlcNAc is present on many proteins that form active polysomes. We identify twenty O-GlcNAcylated core RPs, of which eight are newly reported. We map sites of O-GlcNAc modification on four RPs (L6, L29, L32, and L36). RPS6, a component of the mammalian target of rapamycin (mTOR) signaling pathway, follows different dynamics of O-GlcNAcylation than nutrient-induced phosphorylation. We also show that both O-GlcNAc cycling enzymes OGT and OGAse strongly associate with cytosolic ribosomes. Immunofluorescence experiments demonstrate that OGAse is present uniformly throughout the nucleus, whereas OGT is excluded from the nucleolus. Moreover, nucleolar stress only alters OGAse nuclear staining, but not OGT staining. Lastly, adenovirus-mediated overexpression of OGT, but not of OGAse or GFP control, causes an accumulation of 60S subunits and 80S monosomes. Our results not only establish that O-GlcNAcylation extensively modifies RPs, but also suggest that O-GlcNAc play important roles in regulating translation and ribosome biogenesis.
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Affiliation(s)
- Quira Zeidan
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185, USA
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36
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Song YB, Jhun MA, Park T, Huh WK. Quantitative proteomic analysis of ribosomal protein L35b mutant of Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:676-83. [DOI: 10.1016/j.bbapap.2009.10.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 10/21/2009] [Accepted: 10/22/2009] [Indexed: 01/21/2023]
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37
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Sugihara Y, Honda H, Iida T, Morinaga T, Hino S, Okajima T, Matsuda T, Nadano D. Proteomic Analysis of Rodent Ribosomes Revealed Heterogeneity Including Ribosomal Proteins L10-like, L22-like 1, and L39-like. J Proteome Res 2010; 9:1351-66. [DOI: 10.1021/pr9008964] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Yoshihiko Sugihara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hiroki Honda
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Tomoharu Iida
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Takuma Morinaga
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Shingo Hino
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Tetsuya Okajima
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Tsukasa Matsuda
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Daita Nadano
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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38
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Pöll G, Braun T, Jakovljevic J, Neueder A, Jakob S, Woolford JL, Tschochner H, Milkereit P. rRNA maturation in yeast cells depleted of large ribosomal subunit proteins. PLoS One 2009; 4:e8249. [PMID: 20011513 PMCID: PMC2788216 DOI: 10.1371/journal.pone.0008249] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/13/2009] [Indexed: 11/19/2022] Open
Abstract
The structural constituents of the large eukaryotic ribosomal subunit are 3 ribosomal RNAs, namely the 25S, 5.8S and 5S rRNA and about 46 ribosomal proteins (r-proteins). They assemble and mature in a highly dynamic process that involves more than 150 proteins and 70 small RNAs. Ribosome biogenesis starts in the nucleolus, continues in the nucleoplasm and is completed after nucleo-cytoplasmic translocation of the subunits in the cytoplasm. In this work we created 26 yeast strains, each of which conditionally expresses one of the large ribosomal subunit (LSU) proteins. In vivo depletion of the analysed LSU r-proteins was lethal and led to destabilisation and degradation of the LSU and/or its precursors. Detailed steady state and metabolic pulse labelling analyses of rRNA precursors in these mutant strains showed that LSU r-proteins can be grouped according to their requirement for efficient progression of different steps of large ribosomal subunit maturation. Comparative analyses of the observed phenotypes and the nature of r-protein-rRNA interactions as predicted by current atomic LSU structure models led us to discuss working hypotheses on i) how individual r-proteins control the productive processing of the major 5' end of 5.8S rRNA precursors by exonucleases Rat1p and Xrn1p, and ii) the nature of structural characteristics of nascent LSUs that are required for cytoplasmic accumulation of nascent subunits but are nonessential for most of the nuclear LSU pre-rRNA processing events.
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Affiliation(s)
- Gisela Pöll
- Institut für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Tobias Braun
- Institut für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Jelena Jakovljevic
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Andreas Neueder
- Institut für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - Steffen Jakob
- Institut für Biochemie III, Universität Regensburg, Regensburg, Germany
| | - John L. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (JLW); (HT); (PM)
| | - Herbert Tschochner
- Institut für Biochemie III, Universität Regensburg, Regensburg, Germany
- * E-mail: (JLW); (HT); (PM)
| | - Philipp Milkereit
- Institut für Biochemie III, Universität Regensburg, Regensburg, Germany
- * E-mail: (JLW); (HT); (PM)
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39
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Lumsden T, Bentley AA, Beutler W, Ghosh A, Galkin O, Komar AA. Yeast strains with N-terminally truncated ribosomal protein S5: implications for the evolution, structure and function of the Rps5/Rps7 proteins. Nucleic Acids Res 2009; 38:1261-72. [PMID: 19969550 PMCID: PMC2831326 DOI: 10.1093/nar/gkp1113] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ribosomal protein (rp)S5 belongs to the family of the highly conserved rp's that contains rpS7 from prokaryotes and rpS5 from eukaryotes. Alignment of rpS5/rpS7 from metazoans (Homo sapiens), fungi (Saccharomyces cerevisiae) and bacteria (Escherichia coli) shows that the proteins contain a conserved central/C-terminal core region and possess variable N-terminal regions. Yeast rpS5 is 69 amino acids (aa) longer than the E. coli rpS7 protein; and human rpS5 is 48 aa longer than the rpS7, respectively. To investigate the function of the yeast rpS5 and in particular the role of its N-terminal region, we obtained and characterized yeast strains in which the wild-type yeast rpS5 was replaced by its truncated variants, lacking 13, 24, 30 and 46 N-terminal amino acids, respectively. All mutant yeast strains were viable and displayed only moderately reduced growth rates, with the exception of the strain lacking 46 N-terminal amino acids, which had a doubling time of about 3 h. Biochemical analysis of the mutant yeast strains suggests that the N-terminal part of the eukaryotic and, in particular, yeast rpS5 may impact the ability of 40S subunits to function properly in translation and affect the efficiency of initiation, specifically the recruitment of initiation factors eIF3 and eIF2.
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Affiliation(s)
- Thomas Lumsden
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
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40
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Martinez Barrio A, Eriksson O, Badhai J, Fröjmark AS, Bongcam-Rudloff E, Dahl N, Schuster J. Targeted resequencing and analysis of the Diamond-Blackfan anemia disease locus RPS19. PLoS One 2009; 4:e6172. [PMID: 19587786 PMCID: PMC2703794 DOI: 10.1371/journal.pone.0006172] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 05/27/2009] [Indexed: 11/19/2022] Open
Abstract
Background The Ribosomal protein S19 gene locus (RPS19) has been linked to two kinds of red cell aplasia, Diamond-Blackfan Anemia (DBA) and Transient Erythroblastopenia in Childhood (TEC). Mutations in RPS19 coding sequences have been found in 25% of DBA patients, but not in TEC patients. It has been suggested that non-coding RPS19 sequence variants contribute to the considerable clinical variability in red cell aplasia. We therefore aimed at identifying non-coding variations associated with DBA or TEC phenotypes. Methodology/Principal Findings We targeted a region of 19'980 bp encompassing the RPS19 gene in a cohort of 89 DBA and TEC patients for resequencing. We provide here a catalog of the considerable, previously unrecognized degree of variation in this region. We identified 73 variations (65 SNPs, 8 indels) that all are located outside of the RPS19 open reading frame, and of which 67.1% are classified as novel. We hypothesize that specific alleles in non-coding regions of RPS19 could alter the binding of regulatory proteins or transcription factors. Therefore, we carried out an extensive analysis to identify transcription factor binding sites (TFBS). A series of putative interaction sites coincide with detected variants. Sixteen of the corresponding transcription factors are of particular interest, as they are housekeeping genes or show a direct link to hematopoiesis, tumorigenesis or leukemia (e.g. GATA-1/2, PU.1, MZF-1). Conclusions Specific alleles at predicted TFBSs may alter the expression of RPS19, modify an important interaction between transcription factors with overlapping TFBS or remove an important stimulus for hematopoiesis. We suggest that the detected interactions are of importance for hematopoiesis and could provide new insights into individual response to treatment.
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Affiliation(s)
- Alvaro Martinez Barrio
- The Linnaeus Centre for Bioinformatics Uppsala University/Swedish University of Agricultural Sciences, Uppsala University, Uppsala, Sweden
| | - Oskar Eriksson
- Department of Genetics and Pathology, The Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Jitendra Badhai
- Department of Genetics and Pathology, The Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Anne-Sophie Fröjmark
- Department of Genetics and Pathology, The Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Erik Bongcam-Rudloff
- The Linnaeus Centre for Bioinformatics Uppsala University/Swedish University of Agricultural Sciences, Uppsala University, Uppsala, Sweden
- Department of Animal Breeding and Genetics, Uppsala University, Uppsala, Sweden
| | - Niklas Dahl
- Department of Genetics and Pathology, The Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Jens Schuster
- Department of Genetics and Pathology, The Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- * E-mail:
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41
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Kim TY, Ha CW, Huh WK. Differential subcellular localization of ribosomal protein L7 paralogs in Saccharomyces cerevisiae. Mol Cells 2009; 27:539-46. [PMID: 19466602 DOI: 10.1007/s10059-009-0077-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/23/2009] [Accepted: 03/24/2009] [Indexed: 11/25/2022] Open
Abstract
In Saccharomyces cerevisiae, ribosomal protein L7, one of the approximately 46 ribosomal proteins of the 60S subunit, is encoded by paralogous RPL7A and RPL7B genes. The amino acid sequence identity between Rpl7a and Rpl7b is 97 percent; they differ by only 5 amino acid residues. Interestingly, despite the high sequence homology, Rpl7b is detected in both the cytoplasm and the nucleolus, whereas Rpl7a is detected exclusively in the cytoplasm. A site-directed mutagenesis experiment revealed that the change in the amino acid sequence of Rpl7b does not influence its sub-cellular localization. In addition, introns of RPL7A and RPL7B did not affect the subcellular localization of Rpl7a and Rpl7b. Remarkably, Rpl7b was detected exclusively in the cytoplasm in rpl7a knockout mutant, and overexpression of Rpl7a resulted in its accumulation in the nucleolus, indicating that the subcellular localization of Rpl7a and Rpl7b is influenced by the intracellular level of Rpl7a. Rpl7b showed a wide range of localization patterns, from exclusively cytoplasmic to exclusively nucleolar, in knock-out mutants for some rRNA-processing factors, nuclear pore proteins, and large ribosomal subunit assembly factors. Rpl7a, however, was detected exclusively in the cytoplasm in these mutants. Taken together, these results suggest that although Rpl7a and Rpl7b are paralogous and functionally replaceable with each other, their precise physiological roles may not be identical.
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Affiliation(s)
- Tae-Youl Kim
- School of Biological Sciences, and Research Center for Functional Cellulomics, Institute of Microbiology, Seoul National University, Seoul 151-747, Korea
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42
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Caldarola S, De Stefano MC, Amaldi F, Loreni F. Synthesis and function of ribosomal proteins--fading models and new perspectives. FEBS J 2009; 276:3199-210. [PMID: 19438715 DOI: 10.1111/j.1742-4658.2009.07036.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The synthesis of ribosomal proteins (RPs) has long been known to be a process strongly linked to the growth status of the cell. In vertebrates, this coordination is dependent on RP mRNA translational efficiency, which changes according to physiological circumstances. Despite many years of investigation, the trans-acting factors and the signaling pathways involved in this regulation are still elusive. At the same time, however, new techniques and classic approaches have opened up new perspectives as regards RP regulation and function. In fact, the proteasome seems to play a crucial and unpredicted role in regulating the availability of RPs for subunit assembly. In addition, the study of human ribosomal pathologies and animal models for these diseases has revealed that perturbation in the synthesis and/or function of an RP activates a p53-dependent stress response. Surprisingly, the effect of the ribosomal stress is more dramatic in specific physiological processes: hemopoiesis in humans, and pigmentation in mice. Moreover, alteration of each RP impacts differently on the development of an organism.
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Affiliation(s)
- Sara Caldarola
- Department of Biology, University 'Tor Vergata', Roma, Italy
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43
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Rohozinski J, Anderson ML, Broaddus RE, Edwards CL, Bishop CE. Spermatogenesis associated retrogenes are expressed in the human ovary and ovarian cancers. PLoS One 2009; 4:e5064. [PMID: 19333399 PMCID: PMC2660244 DOI: 10.1371/journal.pone.0005064] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Accepted: 02/06/2009] [Indexed: 12/24/2022] Open
Abstract
Background Ovarian cancer is the second most prevalent gynecologic cancer in women. However, it is by far the most lethal. This is generally attributed to the absence of easily detectable markers specific to ovarian cancers that can be used for early diagnosis and specific therapeutic targets. Methodology/Principal Findings Using end point PCR we have found that a family of retrogenes, previously thought to be expressed only in the male testis during spermatogenesis in man, are also expressed in normal ovarian tissue and a large percentage of ovarian cancers. In man there are at least eleven such autosomal retrogenes, which are intronless copies of genes on the X chromosome, essential for normal spermatogenesis and expressed specifically in the human testis. We tested for the expression of five of the known retrogenes, UTP14C, PGK2, RPL10L, RPL39L and UBL4B in normal human ovary and ovarian cancers. Conclusions/Significance We propose that the activation of the testis specific retrogenes in the ovary and ovarian cancers is of biological significance in humans. Because these retrogenes are specifically expressed in the ovary and ovarian cancers in the female they may prove useful in developing new diagnostic and/or therapeutic targets for ovarian cancer.
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Affiliation(s)
- Jan Rohozinski
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA.
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44
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Simoff I, Moradi H, Nygård O. Functional characterization of ribosomal protein L15 from Saccharomyces cerevisiae. Curr Genet 2009; 55:111-25. [PMID: 19184027 DOI: 10.1007/s00294-009-0228-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 01/08/2009] [Accepted: 01/08/2009] [Indexed: 12/20/2022]
Abstract
In this study we provide general information on the little studied eukaryotic ribosomal protein rpL15. Saccharomyces cerevisiae has two genes, YRPL15A and YRPL15B that could potentially code for yeast rpL15 (YrpL15). YRPL15A is essential while YRPL15B is dispensable. However, a plasmid-borne copy of the YRPL15B gene, controlled by the GAL1 promoter or by the promoter controlling expression of the YRPL15A gene, can functionally complement YrpL15A in yeast cells, while the same gene controlled by the authentic promoter is inactive. Analysis of the levels of YrpL15B-mRNA in yeast cells shows that the YRPL15B gene is inactive in transcription. The function of YrpL15A is highly resilient to single and multiple amino acid substitutions. In addition, minor deletions from both the N- and C-terminal ends of YrpL15A has no effect on protein function, while addition of a C-terminal tag that could be used for detection of plasmid-encoded YrpL15A is detrimental to protein function. YrpL15A could also be replaced by the homologous protein from Arabidopsis thaliana despite almost 30% differences in the amino acid sequence, while the more closely related protein from Schizosaccharomyces pombe was inactive. The lack of function was not caused by a failure of the protein to enter the yeast nucleus.
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45
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Fulle S, Gohlke H. Statics of the ribosomal exit tunnel: implications for cotranslational peptide folding, elongation regulation, and antibiotics binding. J Mol Biol 2009; 387:502-17. [PMID: 19356596 DOI: 10.1016/j.jmb.2009.01.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2008] [Revised: 01/18/2009] [Accepted: 01/21/2009] [Indexed: 10/21/2022]
Abstract
A sophisticated interplay between the static properties of the ribosomal exit tunnel and its functional role in cotranslational processes is revealed by constraint counting on topological network representations of large ribosomal subunits from four different organisms. As for the global flexibility characteristics of the subunit, the results demonstrate a conserved stable structural environment of the tunnel. The findings render unlikely that deformations of the tunnel move peptides down the tunnel in an active manner. Furthermore, the stable environment rules out that the tunnel can adapt widely so as to allow tertiary folding of nascent chains. Nevertheless, there are local zones of flexible nucleotides within the tunnel, between the peptidyl transferase center and the tunnel constriction, and at the tunnel exit. These flexible zones strikingly agree with previously identified folding zones. As for cotranslational elongation regulation, flexible residues in the beta-hairpin of the ribosomal L22 protein were verified, as suggested previously based on structural results. These results support the hypothesis that L22 can undergo conformational changes that regulate the tunnel voyage of nascent polypeptides. Furthermore, rRNA elements, for which conformational changes have been observed upon interaction of the tunnel wall with a nascent SecM peptide, are less strongly coupled to the subunit core. Sequences of coupled rigid clusters are identified between the tunnel and some of these elements, suggesting signal transmission by a domino-like mechanical coupling. Finally, differences in the flexibility of the glycosidic bonds of bases that form antibiotics-binding crevices within the peptidyl transferase center and the tunnel region are revealed for ribosomal structures from different kingdoms. In order to explain antibiotics selectivity, action, and resistance, according to these results, differences in the degrees of freedom of the binding regions may need to be considered.
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Affiliation(s)
- Simone Fulle
- Department of Biological Sciences, Molecular Bioinformatics Group, Goethe University, Frankfurt, Germany
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46
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Peisker K, Braun D, Wölfle T, Hentschel J, Fünfschilling U, Fischer G, Sickmann A, Rospert S. Ribosome-associated complex binds to ribosomes in close proximity of Rpl31 at the exit of the polypeptide tunnel in yeast. Mol Biol Cell 2008; 19:5279-88. [PMID: 18829863 DOI: 10.1091/mbc.e08-06-0661] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Ribosome-associated complex (RAC) consists of the Hsp40 homolog Zuo1 and the Hsp70 homolog Ssz1. The chaperone participates in the biogenesis of newly synthesized polypeptides. Here we have identified yeast Rpl31, a component of the large ribosomal subunit, as a contact point of RAC at the polypeptide tunnel exit. Rpl31 is encoded by RPL31a and RPL31b, two closely related genes. Delta rpl31a Delta rpl31b displayed slow growth and sensitivity to low as well as high temperatures. In addition, Delta rpl31a Delta rpl31b was highly sensitive toward aminoglycoside antibiotics and suffered from defects in translational fidelity. With the exception of sensitivity at elevated temperature, the phenotype resembled yeast strains lacking one of the RAC subunits or Rpl39, another protein localized at the tunnel exit. Defects of Delta rpl31a Delta rpl31b Delta zuo1 did not exceed that of Delta rpl31a Delta rpl31b or Delta zuo1. However, the combined deletion of RPL31a, RPL31b, and RPL39 was lethal. Moreover, RPL39 was a multicopy suppressor, whereas overexpression of RAC failed to rescue growth defects of Delta rpl31a Delta rpl31b. The findings are consistent with a model in that Rpl31 and Rpl39 independently affect a common ribosome function, whereas Rpl31 and RAC are functionally interdependent. Rpl31, while not essential for binding of RAC to the ribosome, might be involved in proper function of the chaperone complex.
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Affiliation(s)
- Kristin Peisker
- Institute of Biochemistry and Molecular Biology, ZBMZ, University of Freiburg, D-79104 Freiburg, Germany
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Regmi S, Rothberg KG, Hubbard JG, Ruben L. The RACK1 signal anchor protein from Trypanosoma brucei associates with eukaryotic elongation factor 1A: a role for translational control in cytokinesis. Mol Microbiol 2008; 70:724-45. [PMID: 18786142 PMCID: PMC2581647 DOI: 10.1111/j.1365-2958.2008.06443.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
RACK1 is a WD-repeat protein that forms signal complexes at appropriate locations in the cell. RACK1 homologues are core components of ribosomes from yeast, plants and mammals. In contrast, a cryo-EM analysis of trypanosome ribosomes failed to detect RACK1, thus eliminating an important translational regulatory mechanism. Here we report that TbRACK1 from Trypanosoma brucei associates with eukaryotic translation elongation factor-1a (eEF1A) as determined by tandem MS of TAP-TbRACK1 affinity eluates, co-sedimentation in a sucrose gradient, and co-precipitation assays. Consistent with these observations, sucrose gradient purified 80S monosomes and translating polysomes each contained TbRACK1. When RNAi was used to deplete cells of TbRACK1, a shift in the polysome profile was observed, while the phosphorylation of a ribosomal protein increased. Under these conditions, cell growth became hypersensitive to the translational inhibitor anisomycin. The kinetoplasts and nuclei were misaligned in the postmitotic cells, resulting in partial cleavage furrow ingression during cytokinesis. Overall, these findings identify eEF1A as a novel TbRACK1 binding partner and establish TbRACK1 as a component of the trypanosome translational apparatus. The synergy between anisomycin and TbRACK1 RNAi suggests that continued translation is required for complete ingression of the cleavage furrow.
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Affiliation(s)
- Sandesh Regmi
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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48
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Zhu Z, Boobis AR, Edwards RJ. Identification of estrogen-responsive proteins in MCF-7 human breast cancer cells using label-free quantitative proteomics. Proteomics 2008; 8:1987-2005. [PMID: 18491314 DOI: 10.1002/pmic.200700901] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
17beta-Estradiol (E(2)) is a key regulatory steroid hormone that is involved in the control of a number of developmental and other functions. The aim of the present work was to identify estrogen-dependent proteomic changes by determining the levels of expressed proteins in MCF-7 human breast cancer cells following treatment with E(2). A number of methods exist for differential analysis of complex proteomic mixtures. Here, a label-free mass spectrometric approach comparing the ion intensities of tryptic peptides was adopted, which was combined with prefractionation of whole cell lysate proteins by 1-D SDS-PAGE. Using this approach, 60 proteins were found to be affected by E(2). These comprised 55 up-regulated and five down-regulated proteins. These proteins varied widely in their physiochemical properties with pIs of 4-12 and molecular weights of 9-500 kDa. Pathway analysis revealed that the majority of changes were related and together describe an up-regulated pathway consistent with the events of cell proliferation. The quantitative approach used here is relatively straightforward, avoids the use of costly labelling reagents, was reproducible within acceptable limits and has a linear response over a useful concentration range.
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Affiliation(s)
- Zheying Zhu
- Department of Experimental Medicine and Toxicology, Division of Investigative Science, Imperial College London, Hammersmith Campus, London, UK
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49
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Varriale A, Torelli G, Bernardi G. Compositional properties and thermal adaptation of 18S rRNA in vertebrates. RNA (NEW YORK, N.Y.) 2008; 14:1492-500. [PMID: 18567811 PMCID: PMC2491464 DOI: 10.1261/rna.957108] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In order to investigate the influence of temperature on the GC level of the paired sequences of ribosomal 18S RNAs in vertebrates, we have studied their base composition in cold- and warm-blooded vertebrates using a stem-by-stem comparison. We observed that a number of stems of 18S ribosomal RNAs (rRNAs) are variable among species and that the majority of such stems are GC richer in warm-blooded than in cold-blooded vertebrates. We also constructed the secondary structures of the 18S rRNAs of a polar fish, a marsupial, and a monotreme to compare them with those of temperate/tropical fishes and of eutherians, respectively. In these cases, differences similar to those already mentioned were found. We conclude that there is a correlation between stem stability and body temperature even within the relatively limited temperature range of vertebrates.
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Affiliation(s)
- Annalisa Varriale
- Laboratory of Molecular Evolution, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
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50
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Bulygin K, Favre A, Baouz-Drahy S, Hountondji C, Vorobjev Y, Ven'yaminova A, Graifer D, Karpova G. Arrangement of 3'-terminus of tRNA on the human ribosome as revealed from cross-linking data. Biochimie 2008; 90:1624-36. [PMID: 18585432 DOI: 10.1016/j.biochi.2008.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 06/02/2008] [Indexed: 10/22/2022]
Abstract
This study is directed towards an important problem concerning the organization of the peptidyl transferase center (PTC) on the mammalian ribosome that cannot be studied by X-ray analysis since crystals of 80S ribosomes are still unavailable. Here, we investigated the arrangement of the 3'-end of tRNA in the 80S ribosomal A and P sites using a tRNA(Asp) analogue that bears a 4-thiouridine (s(4)U) attached to the 3'-terminal adenosine. It was shown that an additional nucleotide s(4)U77 on the 3'-end does not impede codon-dependent binding of the tRNA to the A and P sites of 80S ribosome. Mild UV-irradiation of the ribosomal complexes containing a short appropriately designed mRNA and the tRNA analogue resulted in cross-linking of the analogue exclusively to 28S rRNA. The cross-linking site was detected in the 4302-4540 fragment of the 28S rRNA which belongs to the highly conserved domain V that in prokaryotic ribosomes is involved in the formation of the PTC. Nucleotides cross-linked to the tRNA analogue were determined by means of reverse transcription. A comparison of the results obtained with a dynamic model of mutual arrangement of s(4)U77 of the A site tRNA and nucleotides of 23S rRNA built on the basis of an atomic model for the prokaryotic PTC led to the conclusion that environments of the tRNA 3'-terminus in prokaryotic and eukaryotic ribosomes share a significant extent of similarity, although pronounced differences are also detectable.
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Affiliation(s)
- Konstantin Bulygin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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