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Bharti R, Siebert D, Blombach B, Grimm DG. Systematic analysis of the underlying genomic architecture for transcriptional-translational coupling in prokaryotes. NAR Genom Bioinform 2022; 4:lqac074. [PMID: 36186922 PMCID: PMC9514032 DOI: 10.1093/nargab/lqac074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 09/05/2022] [Accepted: 09/15/2022] [Indexed: 11/12/2022] Open
Abstract
Transcriptional-translational coupling is accepted to be a fundamental mechanism of gene expression in prokaryotes and therefore has been analyzed in detail. However, the underlying genomic architecture of the expression machinery has not been well investigated so far. In this study, we established a bioinformatics pipeline to systematically investigated >1800 bacterial genomes for the abundance of transcriptional and translational associated genes clustered in distinct gene cassettes. We identified three highly frequent cassettes containing transcriptional and translational genes, i.e. rplk-nusG (gene cassette 1; in 553 genomes), rpoA-rplQ-rpsD-rpsK-rpsM (gene cassette 2; in 656 genomes) and nusA-infB (gene cassette 3; in 877 genomes). Interestingly, each of the three cassettes harbors a gene (nusG, rpsD and nusA) encoding a protein which links transcription and translation in bacteria. The analyses suggest an enrichment of these cassettes in pathogenic bacterial phyla with >70% for cassette 3 (i.e. Neisseria, Salmonella and Escherichia) and >50% for cassette 1 (i.e. Treponema, Prevotella, Leptospira and Fusobacterium) and cassette 2 (i.e. Helicobacter, Campylobacter, Treponema and Prevotella). These insights form the basis to analyze the transcriptional regulatory mechanisms orchestrating transcriptional-translational coupling and might open novel avenues for future biotechnological approaches.
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Affiliation(s)
- Richa Bharti
- Technical University of Munich, Campus Straubing for Biotechnology and Sustainability, Bioinformatics, Petersgasse 18, 94315 Straubing, Germany
- Weihenstephan-Triesdorf University of Applied Sciences, Petersgasse 18, 94315 Straubing, Germany
- SynBiofoundry@TUM, Technical University of Munich, Schulgasse 22, 94315 Straubing, Germany
| | - Daniel Siebert
- SynBiofoundry@TUM, Technical University of Munich, Schulgasse 22, 94315 Straubing, Germany
- Technical University of Munich, Campus Straubing for Biotechnology and Sustainability, Microbial Biotechnology, Uferstraße 53, 94315 Straubing, Germany
| | - Bastian Blombach
- SynBiofoundry@TUM, Technical University of Munich, Schulgasse 22, 94315 Straubing, Germany
- Technical University of Munich, Campus Straubing for Biotechnology and Sustainability, Microbial Biotechnology, Uferstraße 53, 94315 Straubing, Germany
| | - Dominik G Grimm
- Technical University of Munich, Campus Straubing for Biotechnology and Sustainability, Bioinformatics, Petersgasse 18, 94315 Straubing, Germany
- Weihenstephan-Triesdorf University of Applied Sciences, Petersgasse 18, 94315 Straubing, Germany
- SynBiofoundry@TUM, Technical University of Munich, Schulgasse 22, 94315 Straubing, Germany
- Technical University of Munich, Department of Informatics, Boltzmannstr. 3, 85748 Garching, Germany
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In vitro characterisation of the MS2 RNA polymerase complex reveals host factors that modulate emesviral replicase activity. Commun Biol 2022; 5:264. [PMID: 35338258 PMCID: PMC8956599 DOI: 10.1038/s42003-022-03178-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 02/17/2022] [Indexed: 11/08/2022] Open
Abstract
The RNA phage MS2 is one of the most important model organisms in molecular biology and virology. Despite its comprehensive characterisation, the composition of the RNA replication machinery remained obscure. Here, we characterised host proteins required to reconstitute the functional replicase in vitro. By combining a purified replicase sub-complex with elements of an in vitro translation system, we confirmed that the three host factors, EF-Ts, EF-Tu, and ribosomal protein S1, are part of the active replicase holocomplex. Furthermore, we found that the translation initiation factors IF1 and IF3 modulate replicase activity. While IF3 directly competes with the replicase for template binding, IF1 appears to act as an RNA chaperone that facilitates polymerase readthrough. Finally, we demonstrate in vitro formation of RNAs containing minimal motifs required for amplification. Our work sheds light on the MS2 replication machinery and provides a new promising platform for cell-free evolution.
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Zhang N, Guo L, Huang L. The Sac10b homolog from Sulfolobus islandicus is an RNA chaperone. Nucleic Acids Res 2020; 48:9273-9284. [PMID: 32761152 PMCID: PMC7498313 DOI: 10.1093/nar/gkaa656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/19/2020] [Accepted: 07/28/2020] [Indexed: 01/08/2023] Open
Abstract
Nucleic acid-binding proteins of the Sac10b family, also known as Alba, are widely distributed in Archaea. However, the physiological roles of these proteins have yet to be clarified. Here, we show that Sis10b, a member of the Sac10b family from the hyperthermophilic archaeon Sulfolobus islandicus, was active in RNA strand exchange, duplex RNA unwinding in vitro and RNA unfolding in a heterologous host cell. This protein exhibited temperature-dependent binding preference for ssRNA over dsRNA and was more efficient in RNA unwinding and RNA unfolding at elevated temperatures. Notably, alanine substitution of a highly conserved basic residue (K) at position 17 in Sis10b drastically reduced the ability of this protein to catalyse RNA strand exchange and RNA unwinding. Additionally, the preferential binding of Sis10b to ssRNA also depended on the presence of K17 or R17. Furthermore, normal growth was restored to a slow-growing Sis10b knockdown mutant by overproducing wild-type Sis10b but not by overproducing K17A in this mutant strain. Our results indicate that Sis10b is an RNA chaperone that likely functions most efficiently at temperatures optimal for the growth of S. islandicus, and K17 is essential for the chaperone activity of the protein.
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Affiliation(s)
- Ningning Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Li Guo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China
| | - Li Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China
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4
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Virtanen JP, Keto-Timonen R, Jaakkola K, Salin N, Korkeala H. Changes in Transcriptome of Yersinia pseudotuberculosis IP32953 Grown at 3 and 28°C Detected by RNA Sequencing Shed Light on Cold Adaptation. Front Cell Infect Microbiol 2018; 8:416. [PMID: 30538955 PMCID: PMC6277586 DOI: 10.3389/fcimb.2018.00416] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 11/09/2018] [Indexed: 11/17/2022] Open
Abstract
Yersinia pseudotuberculosis is a bacterium that not only survives, but also thrives, proliferates, and remains infective at cold-storage temperatures, making it an adept foodborne pathogen. We analyzed the differences in gene expression between Y. pseudotuberculosis IP32953 grown at 3 and 28°C to investigate which genes were significantly more expressed at low temperature at different phases of growth. We isolated and sequenced the RNA from six distinct corresponding growth points at both temperatures to also outline the expression patterns of the differentially expressed genes. Genes involved in motility, chemotaxis, phosphotransferase systems (PTS), and ATP-binding cassette (ABC) transporters of different nutrients such as fructose and mannose showed higher levels of transcripts at 3°C. At the beginning of growth, especially genes involved in securing nutrients, glycolysis, transcription, and translation were upregulated at 3°C. To thrive as well as it does at low temperature, Y. pseudotuberculosis seems to require certain cold shock proteins, especially those encoded by yptb3585, yptb3586, yptb2414, yptb2950, and yptb1423, and transcription factors, like Rho, IF-1, and RbfA, to maintain its protein synthesis. We also found that genes encoding RNA-helicases CsdA (yptb0468), RhlE (yptb1214), and DbpA (yptb1652), which unwind frozen secondary structures of nucleic acids with cold shock proteins, were significantly more expressed at 3°C, indicating that these RNA-helicases are important or even necessary during cold. Genes involved in excreting poisonous spermidine and acquiring compatible solute glycine betaine, by either uptake or biosynthesis, showed higher levels of transcripts at low temperatures. This is the first finding of a strong connection between the aforementioned genes and the cold adaptation of Y. pseudotuberculosis. Understanding the mechanisms behind the cold adaptation of Y. pseudotuberculosis is crucial for controlling its growth during cold storage of food, and will also shed light on microbial cold adaptation in general.
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Affiliation(s)
- Jussa-Pekka Virtanen
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Riikka Keto-Timonen
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Kaisa Jaakkola
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Noora Salin
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Hannu Korkeala
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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5
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Zhang X, Zhou T, Kanwal N, Zhao Y, Bai G, Zhao G. Completion of Eight Gynostemma BL. (Cucurbitaceae) Chloroplast Genomes: Characterization, Comparative Analysis, and Phylogenetic Relationships. FRONTIERS IN PLANT SCIENCE 2017; 8:1583. [PMID: 28955369 PMCID: PMC5600969 DOI: 10.3389/fpls.2017.01583] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/29/2017] [Indexed: 05/22/2023]
Abstract
Gynostemma BL., belonging to the family Cucurbitaceae, is a genus containing 17 creeping herbaceous species mainly distributed in East Asia. It can be divided into two subgenera based on different fruit morphology. Herein, we report eight complete chloroplast genome sequences of the genus Gynostemma, which were obtained by Illumina paired-end sequencing, assembly, and annotation. The length of the eight complete cp genomes ranged from 157,576 bp (G. pentaphyllum) to 158,273 bp (G. laxiflorum). Each encoded 133 genes, including 87 protein-coding genes, 37 tRNA genes, eight rRNA genes, and one pseudogene. The four types of repeated sequences had been discovered and indicated that the repeated structure for species in the Subgen. Triostellum was greater than that for species in the Subgen. Gynostemma. The percentage of variation of the eight cp genomes in different regions were calculated, which demonstrated that the coding and inverted repeats regions were highly conserved. Phylogenetic analysis based on Bayesian inference and maximum likelihood methods strongly supported the phylogenetic position of the genus Gynostemma as a member of family Cucurbitaceae. The phylogenetic relationships among the eight species were clearly resolved using the complete cp genome sequences in this study. It will also provide potential molecular markers and candidate DNA barcodes for future studies and enrich the valuable complete cp genome resources of Cucurbitaceae.
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Affiliation(s)
- Xiao Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Sciences, Northwest UniversityXi'an, China
| | - Tao Zhou
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Sciences, Northwest UniversityXi'an, China
| | - Nazish Kanwal
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Sciences, Northwest UniversityXi'an, China
| | - Yuemei Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Sciences, Northwest UniversityXi'an, China
- College of Biopharmaceutical and Food Engineering, Shangluo UniversityShangluo, China
| | - Guoqing Bai
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Sciences, Northwest UniversityXi'an, China
- Xi'an Botanical Garden of Shaanxi Provence, Institute of Botany of Shaanxi ProvenceXi'an, China
| | - Guifang Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Sciences, Northwest UniversityXi'an, China
- *Correspondence: Guifang Zhao
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6
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Aliyu H, De Maayer P, Cowan D. The genome of the Antarctic polyextremophileNesterenkoniasp. AN1 reveals adaptive strategies for survival under multiple stress conditions. FEMS Microbiol Ecol 2016; 92:fiw032. [DOI: 10.1093/femsec/fiw032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2016] [Indexed: 01/18/2023] Open
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7
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Haider A, Allen SM, Jackson KE, Ralph SA, Habib S. Targeting and function of proteins mediating translation initiation in organelles of Plasmodium falciparum. Mol Microbiol 2015; 96:796-814. [PMID: 25689481 DOI: 10.1111/mmi.12972] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2015] [Indexed: 01/13/2023]
Abstract
The malaria parasite Plasmodium falciparum has two translationally active organelles - the apicoplast and mitochondrion, which import nuclear-encoded translation factors to mediate protein synthesis. Initiation of translation is a complex step wherein initiation factors (IFs) act in a regulated manner to form an initiation complex. We identified putative organellar IFs and investigated the targeting, structure and function of IF1, IF2 and IF3 homologues encoded by the parasite nuclear genome. A single PfIF1 is targeted to the apicoplast. Apart from its critical ribosomal interactions, PfIF1 also exhibited nucleic-acid binding and melting activities and mediated transcription anti-termination. This suggests a prominent ancillary function for PfIF1 in destabilisation of DNA and RNA hairpin loops encountered during transcription and translation of the A+T rich apicoplast genome. Of the three putative IF2 homologues, only one (PfIF2a) was an organellar protein with mitochondrial localisation. We additionally identified an IF3 (PfIF3a) that localised exclusively to the mitochondrion and another protein, PfIF3b, that was apicoplast targeted. PfIF3a exhibited ribosome anti-association activity, and monosome splitting by PfIF3a was enhanced by ribosome recycling factor (PfRRF2) and PfEF-G(Mit). These results fill a gap in our understanding of organellar translation in Plasmodium, which is the site of action of several anti-malarial compounds.
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Affiliation(s)
- Afreen Haider
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Stacey M Allen
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Vic., 3010, Australia
| | - Katherine E Jackson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Vic., 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Vic., 3010, Australia
| | - Saman Habib
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India
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8
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Grand X, Espinoza R, Michel C, Cros S, Chalvon V, Jacobs J, Morel JB. Identification of positive and negative regulators of disease resistance to rice blast fungus using constitutive gene expression patterns. PLANT BIOTECHNOLOGY JOURNAL 2012; 10:840-50. [PMID: 22607456 DOI: 10.1111/j.1467-7652.2012.00703.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Elevated constitutive expression of components of the defence arsenal is associated with quantitative resistance to the rice blast fungus, a phenomenon called preformed defence. While the role of many disease regulators in inducible defence systems has been extensively studied, little attention has been paid so far to genes that regulate preformed defence. In this study, we show by microarray analysis across rice diversity that the preformed defence phenomenon impacts on a large number of defence-related genes without apparently affecting other biological processes. Using a guilt-by-association strategy, we identified two positive regulators that promote constitutive expression of known defence markers and partial resistance to rice blast. The HSF23 gene encodes for a putative member of the heat shock transcription factor family, while CaMBP encodes for a putative Calmodulin-binding protein. Both HSF23 and CaMBP strongly affect preformed defence and also plant growth. Additionally, we identified the OB-fold gene as a negative regulator of blast resistance, which could be involved in RNA stabilization. The OB-fold mutants do not suffer from obvious developmental defects. Taken together, our results prove that our strategy of combining analysis of gene expression diversity with guilt-by-association is a powerful way to identify disease resistance regulators in rice.
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Affiliation(s)
- Xavier Grand
- INRA, UMR BGPI INRA/CIRAD/SupAgro, Campus International de Baillarguet, Montpellier, France
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9
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Tanaka T, Mega R, Kim K, Shinkai A, Masui R, Kuramitsu S, Nakagawa N. A non-cold-inducible cold shock protein homolog mainly contributes to translational control under optimal growth conditions. FEBS J 2012; 279:1014-29. [PMID: 22251463 DOI: 10.1111/j.1742-4658.2012.08492.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cold shock proteins (Csps) include both cold-induced and non-cold-induced proteins, contrary to their name. Cold-induced Csps are well studied; they function in cold acclimation by controlling transcription and translation. Some Csps have been reported to contribute to other cellular processes. However, the functions of non-cold-induced Csps under optimal growth conditions remain unknown. To elucidate these functions, we used transcriptome and proteome analyses as comprehensive approaches and have compared the outputs of wild-type and non-cold-induced Csp-deletion mutant cells. As a model organism, we selected Thermus thermophilus HB8 because it has only two csp genes (ttcsp1 and ttcsp2); ttCsp1 is the only non-cold-induced Csp. Surprisingly, the amount of transcripts and proteins upon deletion of the ttcsp1 gene was quite different. DNA microarray analysis revealed that the deletion of ttcsp1 did not affect the amount of transcripts, although the ttcsp1 gene was constantly expressed in the wild-type cell. Nonetheless, proteomic analysis revealed that the expression levels of many proteins were significantly altered when ttcsp1 was deleted. These results suggest that ttCsp1 functions in translation independent of transcription. Furthermore, ttCsp1 is involved in both the stimulation and inhibition of translation of specific proteins. Here, we have determined the crystal structure of ttCsp1 at 1.65 Å. This is the first report to present the structure of a non-cold-inducible cold shock protein. We also report the nucleotide binding affinity of ttCsp1. Finally, we discuss the functions of non-cold-induced Csps and propose how they modulate the levels of specific proteins to suit the prevailing environmental conditions.
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Affiliation(s)
- Toshiko Tanaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Japan
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10
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Belotserkovsky JM, Dabbs ER, Isaksson LA. Mutations in 16S rRNA that suppress cold-sensitive initiation factor 1 affect ribosomal subunit association. FEBS J 2011; 278:3508-17. [PMID: 21791000 DOI: 10.1111/j.1742-4658.2011.08272.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A mutation in the infA gene encoding initiation factor 1 (IF1) gives rise to a cold-sensitive phenotype. An Escherichia coli strain with this mutation was used as a tool to select for second-site suppressors that compensate for the cold sensitivity and map specifically to rRNA. Several suppressor mutants with altered 16S rRNA that partially restore growth of an IF1 mutant strain in the cold were isolated and characterized. Suppressor mutations were found in helix (h)18, h32, h34 and h41 in 16S rRNA. These mutations are not clustered to any particular region in 16S rRNA and none overlap previously reported sites of interaction with IF1. While the isolated suppressors are structurally diverse, they are functionally related because all affect ribosomal subunit association in vivo. Furthermore, in vitro subunit-association experiments indicate that most of the suppressor mutations directly influence ribosomal subunit association even though none of these are confined to any of the known intersubunit bridges. These results are consistent with the model that IF1 is an rRNA chaperone that induces large-scale conformational changes in the small ribosomal subunit, and as a consequence modulates initiation of translation by affecting subunit association.
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11
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Belotserkovsky JM, Isak GI, Isaksson LA. Suppression of a cold-sensitive mutant initiation factor 1 by alterations in the 23S rRNA maturation region. FEBS J 2011; 278:1745-56. [DOI: 10.1111/j.1742-4658.2011.08099.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Proteins with RNA chaperone activity: a world of diverse proteins with a common task-impediment of RNA misfolding. Biochem Res Int 2010; 2011:532908. [PMID: 21234377 PMCID: PMC3017892 DOI: 10.1155/2011/532908] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 11/12/2010] [Accepted: 11/19/2010] [Indexed: 11/18/2022] Open
Abstract
Proteins with RNA chaperone activity are ubiquitous proteins that play important roles in cellular mechanisms. They prevent RNA from misfolding by loosening misfolded structures without ATP consumption. RNA chaperone activity is studied in vitro and in vivo using oligonucleotide- or ribozyme-based assays. Due to their functional as well as structural diversity, a common chaperoning mechanism or universal motif has not yet been identified. A growing database of proteins with RNA chaperone activity has been established based on evaluation of chaperone activity via the described assays. Although the exact mechanism is not yet understood, it is more and more believed that disordered regions within proteins play an important role. This possible mechanism and which proteins were found to possess RNA chaperone activity are discussed here.
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Surkov S, Nilsson H, Rasmussen LCV, Sperling-Petersen HU, Isaksson LA. Translation initiation region dependency of translation initiation in Escherichia coli by IF1 and kasugamycin. FEBS J 2010; 277:2428-39. [DOI: 10.1111/j.1742-4658.2010.07657.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Abstract
In Escherichia coli, the cold shock response occurs when there is a temperature downshift from 37 degrees C to 15 degrees C, and this response is characterized by induction of several cold shock proteins, including the DEAD-box helicase CsdA, during the acclimation phase. CsdA is involved in a variety of cellular processes. Our previous studies showed that the helicase activity of CsdA is critical for its function in cold shock acclimation of cells and that the only proteins that were able to complement its function were another helicase, RhlE, an RNA chaperone, CspA, and a cold-inducible exoribonuclease, RNase R. Interestingly, other major 3'-to-5' processing exoribonucleases of E. coli, such as polynucleotide phosphorylase and RNase II, cannot complement the cold shock function of CsdA. Here we carried out a domain analysis of RNase R and showed that this protein has two distinct activities, RNase and helicase, which are independent of each other and are due to different domains. Mutant RNase R proteins that lack the RNase activity but exhibit the helicase activity were able to complement the cold shock function of CsdA, suggesting that only the helicase activity of RNase R is essential for complementation of the cold shock function of CsdA. We also observed that in vivo deletion of the two cold shock domains resulted in a loss of the ability of RNase R to complement the cold shock function of CsdA. We further demonstrated that RNase R exhibits helicase activity in vitro independent of its RNase activity. Our results shed light on the unique properties of RNase R and how it is distinct from other exoribonucleases in E. coli.
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15
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Phadtare S, Severinov K. Comparative analysis of changes in gene expression due to RNA melting activities of translation initiation factor IF1 and a cold shock protein of the CspA family. Genes Cells 2009; 14:1227-39. [DOI: 10.1111/j.1365-2443.2009.01346.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Luo X, Hsiao HH, Bubunenko M, Weber G, Court DL, Gottesman ME, Urlaub H, Wahl MC. Structural and functional analysis of the E. coli NusB-S10 transcription antitermination complex. Mol Cell 2009; 32:791-802. [PMID: 19111659 DOI: 10.1016/j.molcel.2008.10.028] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 09/24/2008] [Accepted: 10/21/2008] [Indexed: 11/18/2022]
Abstract
Protein S10 is a component of the 30S ribosomal subunit and participates together with NusB protein in processive transcription antitermination. The molecular mechanisms by which S10 can act as a translation or a transcription factor are not understood. We used complementation assays and recombineering to delineate regions of S10 dispensable for antitermination, and determined the crystal structure of a transcriptionally active NusB-S10 complex. In this complex, S10 adopts the same fold as in the 30S subunit and is blocked from simultaneous association with the ribosome. Mass spectrometric mapping of UV-induced crosslinks revealed that the NusB-S10 complex presents an intermolecular, composite, and contiguous binding surface for RNAs containing BoxA antitermination signals. Furthermore, S10 overproduction complemented a nusB null phenotype. These data demonstrate that S10 and NusB together form a BoxA-binding module, that NusB facilitates entry of S10 into the transcription machinery, and that S10 represents a central hub in processive antitermination.
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Affiliation(s)
- Xiao Luo
- Research Group X-Ray Crystallography, Max-Planck-Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
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17
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Lodato PB, Kaper JB. Post-transcriptional processing of the LEE4 operon in enterohaemorrhagic Escherichia coli. Mol Microbiol 2008; 71:273-90. [PMID: 19019141 DOI: 10.1111/j.1365-2958.2008.06530.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) employs a type III secretion system (T3SS) to export translocator and effector proteins required for mucosal colonization. The T3SS is encoded in a pathogenicity island called the locus of enterocyte effacement (LEE) that is organized in five major operons, LEE1 to LEE5. LEE4 encodes a regulator of secretion (SepL), translocators (EspA, D and B), two chaperones (CesD2 and L0017), a T3SS component (EscF) and an effector protein (EspF). It was originally proposed that the esp transcript is transcribed from a promoter located at the end of sepL but other authors suggested that this transcript is the result of a post-transcriptional processing event. In this study, we established that the espADB mRNA is generated by post-transcriptional processing at the end of the sepL coding sequence. RNase E is the endonuclease involved in the cleavage, but the interaction of this enzyme with other proteins through its C-terminal half is dispensable. A putative transcription termination event in the cesD2 coding region would generate the 3' end of the transcript. Similar to what has been described for other processed transcripts, the cleavage of LEE4 seems a mechanism to differentially regulate SepL and Esp protein production.
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Affiliation(s)
- Patricia B Lodato
- Center for Vaccine Development and Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St, Baltimore, MD 21201, USA
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Vila-Sanjurjo A. Modification of the Ribosome and the Translational Machinery during Reduced Growth Due to Environmental Stress. EcoSal Plus 2008; 3. [PMID: 26443727 DOI: 10.1128/ecosalplus.2.5.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Indexed: 06/05/2023]
Abstract
Escherichia coli strains normally used under laboratory conditions have been selected for maximum growth rates and require maximum translation efficiency. Recent studies have shed light on the structural and functional changes undergone by the translational machinery in E. coli during heat and cold shock and upon entry into stationary phase. In these situations both the composition and the partitioning of this machinery into the different pools of cellular ribosomes are modified. As a result, the translational capacity of the cell is dramatically altered. This review provides a comprehensive account of these modifications, regardless of whether or not their underlying mechanisms and their effects on cellular physiology are known. Not only is the composition of the ribosome modified upon entry into stationary phase, but the modification of other components of the translational machinery, such as elongation factor Tu (EFTu) and tRNAs, has also been observed. Hibernation-promoting factor (HPF), paralog protein Y (PY), and ribosome modulation factor (RMF) may also be related to the general protection against environmental stress observed in stationary-phase E. coli cells, a role that would not be revealed necessarily by the viability assays. Even for the best-characterized ribosome-associated factors induced under stress (RMF, PY, and initiation factors), we are far from a complete understanding of their modes of action.
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Rasmussen LCV, Jensen JM, Croitoru V, Sperling-Petersen HU, Mortensen KK. Production and epitope characterization of mAbs specific for translation factor IF1. Biochem Biophys Res Commun 2007; 364:72-8. [DOI: 10.1016/j.bbrc.2007.09.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Accepted: 09/24/2007] [Indexed: 11/15/2022]
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