1
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Powell BM, Davis JH. Learning structural heterogeneity from cryo-electron sub-tomograms with tomoDRGN. Nat Methods 2024; 21:1525-1536. [PMID: 38459385 DOI: 10.1038/s41592-024-02210-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 02/13/2024] [Indexed: 03/10/2024]
Abstract
Cryo-electron tomography (cryo-ET) enables observation of macromolecular complexes in their native, spatially contextualized cellular environment. Cryo-ET processing software to visualize such complexes at nanometer resolution via iterative alignment and averaging are well developed but rely upon assumptions of structural homogeneity among the complexes of interest. Recently developed tools allow for some assessment of structural diversity but have limited capacity to represent highly heterogeneous structures, including those undergoing continuous conformational changes. Here we extend the highly expressive cryoDRGN (Deep Reconstructing Generative Networks) deep learning architecture, originally created for single-particle cryo-electron microscopy analysis, to cryo-ET. Our new tool, tomoDRGN, learns a continuous low-dimensional representation of structural heterogeneity in cryo-ET datasets while also learning to reconstruct heterogeneous structural ensembles supported by the underlying data. Using simulated and experimental data, we describe and benchmark architectural choices within tomoDRGN that are uniquely necessitated and enabled by cryo-ET. We additionally illustrate tomoDRGN's efficacy in analyzing diverse datasets, using it to reveal high-level organization of human immunodeficiency virus (HIV) capsid complexes assembled in virus-like particles and to resolve extensive structural heterogeneity among ribosomes imaged in situ.
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Affiliation(s)
- Barrett M Powell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Joseph H Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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2
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Du M, Deng C, Yu T, Zhou Q, Zeng F. YjgA plays dual roles in enhancing PTC maturation. Nucleic Acids Res 2024; 52:7947-7960. [PMID: 38842932 PMCID: PMC11260487 DOI: 10.1093/nar/gkae469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/07/2024] Open
Abstract
Ribosome biogenesis is a highly regulated cellular process that involves the control of numerous assembly factors. The small protein YjgA has been reported to play a role in the late stages of 50S assembly. However, the precise molecular mechanism underlying its function remains unclear. In this study, cryo-electron microscopy (cryo-EM) structures revealed that depletion of YjgA or its N-terminal loop in Escherichia coli both lead to the accumulation of immature 50S particles with structural abnormalities mainly in peptidyl transferase center (PTC) and H68/69 region. CryoDRGN analysis uncovered 8 and 6 distinct conformations of pre50S for ΔyjgA and YjgA-ΔNloop, respectively. These conformations highlighted the role of the N-terminal loop of YjgA in integrating uL16 and stabilizing H89 in PTC, which was further verified by the pull-down assays of YjgA and its mutants with uL16. Together with the function of undocking H68 through the binding of its C-terminal CTLH-like domain to the base of the L1 stalk, YjgA facilitates the maturation of PTC. This study identified critical domains of YjgA contributing to 50S assembly efficiency, providing a comprehensive understanding of the dual roles of YjgA in accelerating ribosome biogenesis and expanding our knowledge of the intricate processes governing cellular protein synthesis.
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Affiliation(s)
- Mengtan Du
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055, People's Republic of China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055 Guangdong, People's Republic of China
| | - Chenke Deng
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055, People's Republic of China
| | - Ting Yu
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055, People's Republic of China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055 Guangdong, People's Republic of China
| | - Qixin Zhou
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055, People's Republic of China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055 Guangdong, People's Republic of China
| | - Fuxing Zeng
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055, People's Republic of China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055 Guangdong, People's Republic of China
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3
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Blackwell AM, Jami-Alahmadi Y, Nasamu AS, Kudo S, Senoo A, Slam C, Tsumoto K, Wohlschlegel JA, Caaveiro JMM, Goldberg DE, Sigala PA. Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596652. [PMID: 38853871 PMCID: PMC11160694 DOI: 10.1101/2024.05.30.596652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, Plasmodium falciparum parasites internalize and digest abundant host hemoglobin within the digestive vacuole. This massive catabolic process generates copious free heme, most of which is biomineralized into inert hemozoin. Parasites also express a divergent heme oxygenase (HO)-like protein (PfHO) that lacks key active-site residues and has lost canonical HO activity. The cellular role of this unusual protein that underpins its retention by parasites has been unknown. To unravel PfHO function, we first determined a 2.8 Å-resolution X-ray structure that revealed a highly α-helical fold indicative of distant HO homology. Localization studies unveiled PfHO targeting to the apicoplast organelle, where it is imported and undergoes N-terminal processing but retains most of the electropositive transit peptide. We observed that conditional knockdown of PfHO was lethal to parasites, which died from defective apicoplast biogenesis and impaired isoprenoid-precursor synthesis. Complementation and molecular-interaction studies revealed an essential role for the electropositive N-terminus of PfHO, which selectively associates with the apicoplast genome and enzymes involved in nucleic acid metabolism and gene expression. PfHO knockdown resulted in a specific deficiency in levels of apicoplast-encoded RNA but not DNA. These studies reveal an essential function for PfHO in apicoplast maintenance and suggest that Plasmodium repurposed the conserved HO scaffold from its canonical heme-degrading function in the ancestral chloroplast to fulfill a critical adaptive role in organelle gene expression.
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Affiliation(s)
| | | | - Armiyaw S. Nasamu
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
| | - Shota Kudo
- Department of Chemistry & Biotechnology, The University of Tokyo, Tokyo, Japan
| | - Akinobu Senoo
- Department of Protein Drug Discovery, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Celine Slam
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - Kouhei Tsumoto
- Department of Chemistry & Biotechnology, The University of Tokyo, Tokyo, Japan
- Department of Bioengineering, University of Tokyo, Tokyo, Japan
| | | | - Jose M. M. Caaveiro
- Department of Chemistry & Biotechnology, The University of Tokyo, Tokyo, Japan
| | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
| | - Paul A. Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
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4
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Seffouh A, Nikolay R, Ortega J. Critical steps in the assembly process of the bacterial 50S ribosomal subunit. Nucleic Acids Res 2024; 52:4111-4123. [PMID: 38554105 PMCID: PMC11077053 DOI: 10.1093/nar/gkae199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 03/02/2024] [Accepted: 03/07/2024] [Indexed: 04/01/2024] Open
Abstract
During assembly, ribosomal particles in bacteria fold according to energy landscapes comprised of multiple parallel pathways. Cryo-electron microscopy studies have identified a critical maturation step that occurs during the late assembly stages of the 50S subunit in Bacillus subtilis. This step acts as a point of convergency for all the parallel assembly pathways of the subunit, where an assembly intermediate accumulates in a 'locked' state, causing maturation to pause. Assembly factors then act on this critical step to 'unlock' the last maturation steps involving the functional sites. Without these factors, the 50S subunit fails to complete its assembly, causing cells to die due to a lack of functional ribosomes to synthesize proteins. In this review, we analyze these findings in B. subtilis and examine other cryo-EM studies that have visualized assembly intermediates in different bacterial species, to determine if convergency points in the ribosome assembly process are a common theme among bacteria. There are still gaps in our knowledge, as these methodologies have not yet been applied to diverse species. However, identifying and characterizing these convergency points can reveal how different bacterial species implement unique mechanisms to regulate critical steps in the ribosome assembly process.
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Affiliation(s)
- Amal Seffouh
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Rainer Nikolay
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
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5
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Sarıgül İ, Žukova A, Alparslan E, Remm S, Pihlak M, Kaldalu N, Tenson T, Maiväli Ü. Involvement of Escherichia coli YbeX/CorC in ribosomal metabolism. Mol Microbiol 2024; 121:984-1001. [PMID: 38494741 DOI: 10.1111/mmi.15248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/19/2024]
Abstract
YbeX of Escherichia coli, a member of the CorC protein family, is encoded in the same operon with ribosome-associated proteins YbeY and YbeZ. Here, we report the involvement of YbeX in ribosomal metabolism. The ΔybeX cells accumulate distinct 16S rRNA degradation intermediates in the 30S particles and the 70S ribosomes. E. coli lacking ybeX has a lengthened lag phase upon outgrowth from the stationary phase. This growth phenotype is heterogeneous at the individual cell level and especially prominent under low extracellular magnesium levels. The ΔybeX strain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics that have in common the ability to induce the cold shock response in E. coli. Although generally milder, the phenotypes of the ΔybeX mutant overlap with those caused by ybeY deletion. A genetic screen revealed partial compensation of the ΔybeX growth phenotype by the overexpression of YbeY. These findings indicate an interconnectedness among the ybeZYX operon genes, highlighting their roles in ribosomal assembly and/or degradation.
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Affiliation(s)
- İsmail Sarıgül
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Amata Žukova
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Emel Alparslan
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Sille Remm
- Institute of Technology, University of Tartu, Tartu, Estonia
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
| | - Margus Pihlak
- Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Niilo Kaldalu
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Tanel Tenson
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Ülo Maiväli
- Institute of Technology, University of Tartu, Tartu, Estonia
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6
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Singh J, Singh S, Emam EAF, Varshney U. Role of Rmd9p in 3'-end processing of mitochondrial 15S rRNA in Saccharomyces cerevisiae. Mitochondrion 2024; 76:101876. [PMID: 38599301 DOI: 10.1016/j.mito.2024.101876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/05/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
Ribosome biogenesis, involving processing/assembly of rRNAs and r-proteins is a vital process. In Saccharomyces cerevisiae mitochondria, ribosomal small subunit comprises 15S rRNA (15S). While the 15S 5'-end processing uses Ccm1p and Pet127p, the mechanisms of the 3'-end processing remain unclear. We reveal involvement of Rmd9p in safeguarding/processing 15S 3'-end. Rmd9p deficiency results in a cleavage at a position 183 nucleotides upstream of 15S 3'-end, and in the loss of the 3'-minor domain. Rmd9p binds to the sequences in the 3'-end region of 15S, and a genetic interaction between rmd9 and dss1 indicates that Rmd9p regulates/limits mtEXO activity during the 3'-end spacer processing.
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Affiliation(s)
- Jitendra Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Sudhir Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Elhassan Ali Fathi Emam
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
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7
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Hao Y, Hulscher RM, Zinshteyn B, Woodson SA. Late consolidation of rRNA structure during co-transcriptional assembly in E. coli by time-resolved DMS footprinting. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.574868. [PMID: 38260533 PMCID: PMC10802402 DOI: 10.1101/2024.01.10.574868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The production of new ribosomes requires proper folding of the rRNA and the addition of more than 50 ribosomal proteins. The structures of some assembly intermediates have been determined by cryo-electron microscopy, yet these structures do not provide information on the folding dynamics of the rRNA. To visualize the changes in rRNA structure during ribosome assembly in E. coli cells, transcripts were pulse-labeled with 4-thiouridine and the structure of newly made rRNA probed at various times by dimethyl sulfate modification and mutational profiling sequencing (4U-DMS-MaPseq). The in-cell DMS modification patterns revealed that many long-range rRNA tertiary interactions and protein binding sites through the 16S and 23S rRNA remain partially unfolded 1.5 min after transcription. By contrast, the active sites were continually shielded from DMS modification, suggesting that these critical regions are guarded by cellular factors throughout assembly. Later, bases near the peptidyl tRNA site exhibited specific rearrangements consistent with the binding and release of assembly factors. Time-dependent structure-probing in cells suggests that many tertiary interactions throughout the new ribosomal subunits remain mobile or unfolded until the late stages of subunit maturation.
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Affiliation(s)
- Yumeng Hao
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ryan M. Hulscher
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Boris Zinshteyn
- Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Sarah A. Woodson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
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8
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LaPeruta AJ, Micic J, Woolford Jr. JL. Additional principles that govern the release of pre-ribosomes from the nucleolus into the nucleoplasm in yeast. Nucleic Acids Res 2023; 51:10867-10883. [PMID: 35736211 PMCID: PMC10639060 DOI: 10.1093/nar/gkac430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 05/05/2022] [Accepted: 06/20/2022] [Indexed: 11/14/2022] Open
Abstract
During eukaryotic ribosome biogenesis, pre-ribosomes travel from the nucleolus, where assembly is initiated, to the nucleoplasm and then are exported to the cytoplasm, where assembly concludes. Although nuclear export of pre-ribosomes has been extensively investigated, the release of pre-ribosomes from the nucleolus is an understudied phenomenon. Initial data indicate that unfolded rRNA interacts in trans with nucleolar components and that, when rRNA folds due to ribosomal protein (RP) binding, the number of trans interactions drops below the threshold necessary for nucleolar retention. To validate and expand on this idea, we performed a bioinformatic analysis of the protein components of the Saccharomyces cerevisiae ribosome assembly pathway. We found that ribosome biogenesis factors (RiBi factors) contain significantly more predicted trans interacting regions than RPs. We also analyzed cryo-EM structures of ribosome assembly intermediates to determine how nucleolar pre-ribosomes differ from post-nucleolar pre-ribosomes, specifically the capacity of RPs, RiBi factors, and rRNA components to interact in trans. We observed a significant decrease in the theoretical trans-interacting capability of pre-ribosomes between nucleolar and post-nucleolar stages of assembly due to the release of RiBi factors from particles and the folding of rRNA. Here, we provide a mechanism for the release of pre-ribosomes from the nucleolus.
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Affiliation(s)
- Amber J LaPeruta
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jelena Micic
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - John L Woolford Jr.
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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9
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Warke M, Sarkar D, Schaerer L, Vohs T, Techtmann S, Datta R. Comparative assessment of bacterial diversity and composition in arsenic hyperaccumulator, Pteris vittata L. and non-accumulator, Pteris ensiformis Burm. CHEMOSPHERE 2023; 340:139812. [PMID: 37597630 DOI: 10.1016/j.chemosphere.2023.139812] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 08/11/2023] [Accepted: 08/12/2023] [Indexed: 08/21/2023]
Abstract
The use of arsenic (As) for various industrial and agricultural applications has led to worldwide environmental contamination. Phytoremediation using hyperaccumulators is a sustainable soil As mitigation strategy. Microbial processes play an important role in the tolerance and uptake of trace elements such as in plants. The rhizospheric and endophytic microbial communities are responsible for accelerating the mobility of trace elements around the roots and the production of plant growth-promoting compounds and enzymes. Several studies have reported that the As hyperaccumulator, Pteris vittata L. (PV) influences the microbial community in its rhizosphere and roots. Deciphering the differences in the microbiomes of hyperaccumulators and non-accumulators is crucial in understanding the mechanism of hyperaccumulation. We hypothesized that there are significant differences in the microbiome of roots, rhizospheric soil, and bulk soil between the hyperaccumulator PV and a non-accumulator of the same genus, Pteris ensiformis Burm. (PE), and that the differential recruitment of bacterial communities provides PV with an advantage in As contaminated soil. We compared root endophytic, rhizospheric, and bulk soil microbial communities between PV and PE species grown in As-contaminated soil in a greenhouse setting. There was a significant difference (p < 0.001) in the microbiome of the three compartments between the ferns. Differential abundance analysis showed 328 Amplicon Sequence Variants (ASVs) enriched in PV compared to 172 in PE. The bulk and rhizospheric soil of both ferns were abundant in As-resistant genera. However, As-tolerant root endophytic genera were present in PV but absent in PE. Our findings show that there is a difference between the bacterial composition of an As hyperaccumulator and a non-accumulator species grown in As-contaminated soil. These differences need to be further explored to develop strategies for improving the efficiency of metal uptake in plants growing in As polluted soil.
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Affiliation(s)
- Manas Warke
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Dibyendu Sarkar
- Department of Civil, Environmental and Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - Laura Schaerer
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Tara Vohs
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Stephen Techtmann
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA.
| | - Rupali Datta
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA.
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10
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Shea J, Davis L, Quaye B, Gedeon T. Ribosome Abundance Control in Prokaryotes. Bull Math Biol 2023; 85:119. [PMID: 37861893 DOI: 10.1007/s11538-023-01212-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/06/2023] [Indexed: 10/21/2023]
Abstract
Cell growth is an essential phenotype of any unicellular organism and it crucially depends on precise control of protein synthesis. We construct a model of the feedback mechanisms that regulate abundance of ribosomes in E. coli, a prototypical prokaryotic organism. Since ribosomes are needed to produce more ribosomes, the model includes a positive feedback loop central to the control of cell growth. Our analysis of the model shows that there can be only two coexisting equilibrium states across all 23 parameters. This precludes the existence of hysteresis, suggesting that the ribosome abundance changes continuously with parameters. These states are related by a transcritical bifurcation, and we provide an analytic formula for parameters that admit either state.
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Affiliation(s)
- Jacob Shea
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717, USA
| | - Lisa Davis
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717, USA
| | - Bright Quaye
- Department of Economics, Washington University, St. Louis, MO, USA
| | - Tomas Gedeon
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717, USA.
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11
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Narayan G, Gracia Mazuca LA, Cho SS, Mohl JE, Koculi E. RNA Post-transcriptional Modifications of an Early-Stage Large-Subunit Ribosomal Intermediate. Biochemistry 2023; 62:2908-2915. [PMID: 37751522 PMCID: PMC11088935 DOI: 10.1021/acs.biochem.3c00291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Protein production by ribosomes is fundamental to life, and proper assembly of the ribosome is required for protein production. The RNA, which is post-transcriptionally modified, provides the platform for ribosome assembly. Thus, a complete understanding of ribosome assembly requires the determination of the RNA post-transcriptional modifications in all of the ribosome assembly intermediates and on each pathway. There are 26 RNA post-transcriptional modifications in 23S RNA of the mature Escherichia coli (E. coli) large ribosomal subunit. The levels of these modifications have been investigated extensively only for a small number of large subunit intermediates and under a limited number of cellular and environmental conditions. In this study, we determined the level of incorporations of 2-methyl adenosine, 3-methyl pseudouridine, 5-hydroxycytosine, and seven pseudouridines in an early-stage E. coli large-subunit assembly intermediate with a sedimentation coefficient of 27S. The 27S intermediate is one of three large subunit intermediates accumulated in E. coli cells lacking the DEAD-box RNA helicase DbpA and expressing the helicase inactive R331A DbpA construct. The majority of the investigated modifications are incorporated into the 27S large subunit intermediate to similar levels to those in the mature 50S large subunit, indicating that these early modifications or the enzymes that incorporate them play important roles in the initial events of large subunit ribosome assembly.
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MESH Headings
- RNA Processing, Post-Transcriptional
- Escherichia coli/genetics
- Escherichia coli/metabolism
- RNA, Bacterial/metabolism
- RNA, Bacterial/genetics
- RNA, Bacterial/chemistry
- Escherichia coli Proteins/metabolism
- Escherichia coli Proteins/genetics
- RNA, Ribosomal, 23S/metabolism
- RNA, Ribosomal, 23S/genetics
- RNA, Ribosomal, 23S/chemistry
- Ribosome Subunits, Large, Bacterial/metabolism
- Ribosome Subunits, Large, Bacterial/genetics
- DEAD-box RNA Helicases/metabolism
- DEAD-box RNA Helicases/genetics
- Pseudouridine/metabolism
- Ribosomes/metabolism
- Ribosomes/genetics
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Affiliation(s)
- Gyan Narayan
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Luis A Gracia Mazuca
- Bioinformatics Program, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Samuel S Cho
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States
- Department of Computer Science, Wake Forest University, Winston-Salem, North Carolina 27109, United States
| | - Jonathon E Mohl
- Bioinformatics Program, The University of Texas at El Paso, El Paso, Texas 79968, United States
- Department of Mathematical Sciences, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Eda Koculi
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, El Paso, Texas 79968, United States
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12
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Gruffaz C, Smirnov A. GTPase Era at the heart of ribosome assembly. Front Mol Biosci 2023; 10:1263433. [PMID: 37860580 PMCID: PMC10582724 DOI: 10.3389/fmolb.2023.1263433] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023] Open
Abstract
Ribosome biogenesis is a key process in all organisms. It relies on coordinated work of multiple proteins and RNAs, including an array of assembly factors. Among them, the GTPase Era stands out as an especially deeply conserved protein, critically required for the assembly of bacterial-type ribosomes from Escherichia coli to humans. In this review, we bring together and critically analyze a wealth of phylogenetic, biochemical, structural, genetic and physiological data about this extensively studied but still insufficiently understood factor. We do so using a comparative and, wherever possible, synthetic approach, by confronting observations from diverse groups of bacteria and eukaryotic organelles (mitochondria and chloroplasts). The emerging consensus posits that Era intervenes relatively early in the small subunit biogenesis and is essential for the proper shaping of the platform which, in its turn, is a prerequisite for efficient translation. The timing of Era action on the ribosome is defined by its interactions with guanosine nucleotides [GTP, GDP, (p)ppGpp], ribosomal RNA, and likely other factors that trigger or delay its GTPase activity. As a critical nexus of the small subunit biogenesis, Era is subject to sophisticated regulatory mechanisms at the transcriptional, post-transcriptional, and post-translational levels. Failure of these mechanisms or a deficiency in Era function entail dramatic generalized consequences for the protein synthesis and far-reaching, pleiotropic effects on the organism physiology, such as the Perrault syndrome in humans.
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Affiliation(s)
- Christelle Gruffaz
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
| | - Alexandre Smirnov
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
- University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
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13
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Sun J, Kinman LF, Jahagirdar D, Ortega J, Davis JH. KsgA facilitates ribosomal small subunit maturation by proofreading a key structural lesion. Nat Struct Mol Biol 2023; 30:1468-1480. [PMID: 37653244 PMCID: PMC10710901 DOI: 10.1038/s41594-023-01078-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 07/25/2023] [Indexed: 09/02/2023]
Abstract
Ribosome assembly is orchestrated by many assembly factors, including ribosomal RNA methyltransferases, whose precise role is poorly understood. Here, we leverage the power of cryo-EM and machine learning to discover that the E. coli methyltransferase KsgA performs a 'proofreading' function in the assembly of the small ribosomal subunit by recognizing and partially disassembling particles that have matured but are not competent for translation. We propose that this activity allows inactive particles an opportunity to reassemble into an active state, thereby increasing overall assembly fidelity. Detailed structural quantifications in our datasets additionally enabled the expansion of the Nomura assembly map to highlight rRNA helix and r-protein interdependencies, detailing how the binding and docking of these elements are tightly coupled. These results have wide-ranging implications for our understanding of the quality-control mechanisms governing ribosome biogenesis and showcase the power of heterogeneity analysis in cryo-EM to unveil functionally relevant information in biological systems.
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Affiliation(s)
- Jingyu Sun
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Laurel F Kinman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Dushyant Jahagirdar
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
- Centre for Structural Biology, McGill University, Montreal, Quebec, Canada.
| | - Joseph H Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Computational and Systems Biology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA.
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14
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Bose N, Moore SD. Variable Region Sequences Influence 16S rRNA Performance. Microbiol Spectr 2023; 11:e0125223. [PMID: 37212673 PMCID: PMC10269663 DOI: 10.1128/spectrum.01252-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/03/2023] [Indexed: 05/23/2023] Open
Abstract
16S rRNA gene sequences are commonly analyzed for taxonomic and phylogenetic studies because they contain variable regions that can help distinguish different genera. However, intra-genus distinction using variable region homology is often impossible due to the high overall sequence identities among closely related species, even though some residues may be conserved within respective species. Using a computational method that included the allelic diversity within individual genomes, we discovered that certain Escherichia and Shigella species can be distinguished by a multi-allelic 16S rRNA variable region single nucleotide polymorphism (SNP). To evaluate the performance of 16S rRNAs with altered variable regions, we developed an in vivo system that measures the acceptance and distribution of variant 16S rRNAs into a large pool of natural versions supporting normal translation and growth. We found that 16S rRNAs containing evolutionarily disparate variable regions were underpopulated both in ribosomes and in active translation pools, even for an SNP. Overall, this study revealed that variable region sequences can substantially influence the performance of 16S rRNAs and that this biological constraint can be leveraged to justify refining taxonomic assignments of variable region sequence data. IMPORTANCE This study reevaluates the notion that 16S rRNA gene variable region sequences are uninformative for intra-genus classification and that single nucleotide variations within them have no consequence to strains that bear them. We demonstrated that the performance of 16S rRNAs in Escherichia coli can be negatively impacted by sequence changes in variable regions, even for single nucleotide changes that are native to closely related Escherichia and Shigella species; thus, biological performance is likely constraining the evolution of variable regions in bacteria. Further, the native nucleotide variations we tested occur in all strains of their respective species and across their multiple 16S rRNA gene copies, suggesting that these species evolved beyond what would be discerned from a consensus sequence comparison. Therefore, this work also reveals that the multiple 16S rRNA gene alleles found in most bacteria can provide more informative phylogenetic and taxonomic detail than a single reference allele.
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Affiliation(s)
- Nikhil Bose
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Sean D. Moore
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
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15
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Powell BM, Davis JH. Learning structural heterogeneity from cryo-electron sub-tomograms with tomoDRGN. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.542975. [PMID: 37398315 PMCID: PMC10312494 DOI: 10.1101/2023.05.31.542975] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cryo-electron tomography (cryo-ET) allows one to observe macromolecular complexes in their native, spatially contextualized environment. Tools to visualize such complexes at nanometer resolution via iterative alignment and averaging are well-developed but rely on assumptions of structural homogeneity among the complexes under consideration. Recently developed downstream analysis tools allow for some assessment of macromolecular diversity but have limited capacity to represent highly heterogeneous macromolecules, including those undergoing continuous conformational changes. Here, we extend the highly expressive cryoDRGN deep learning architecture, originally created for cryo-electron microscopy single particle analysis, to sub-tomograms. Our new tool, tomoDRGN, learns a continuous low-dimensional representation of structural heterogeneity in cryo-ET datasets while also learning to reconstruct a large, heterogeneous ensemble of structures supported by the underlying data. Using simulated and experimental data, we describe and benchmark architectural choices within tomoDRGN that are uniquely necessitated and enabled by cryo-ET data. We additionally illustrate tomoDRGN's efficacy in analyzing an exemplar dataset, using it to reveal extensive structural heterogeneity among ribosomes imaged in situ.
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Affiliation(s)
- Barrett M. Powell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Joseph H. Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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16
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Gor K, Duss O. Emerging Quantitative Biochemical, Structural, and Biophysical Methods for Studying Ribosome and Protein-RNA Complex Assembly. Biomolecules 2023; 13:biom13050866. [PMID: 37238735 DOI: 10.3390/biom13050866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Ribosome assembly is one of the most fundamental processes of gene expression and has served as a playground for investigating the molecular mechanisms of how protein-RNA complexes (RNPs) assemble. A bacterial ribosome is composed of around 50 ribosomal proteins, several of which are co-transcriptionally assembled on a ~4500-nucleotide-long pre-rRNA transcript that is further processed and modified during transcription, the entire process taking around 2 min in vivo and being assisted by dozens of assembly factors. How this complex molecular process works so efficiently to produce an active ribosome has been investigated over decades, resulting in the development of a plethora of novel approaches that can also be used to study the assembly of other RNPs in prokaryotes and eukaryotes. Here, we review biochemical, structural, and biophysical methods that have been developed and integrated to provide a detailed and quantitative understanding of the complex and intricate molecular process of bacterial ribosome assembly. We also discuss emerging, cutting-edge approaches that could be used in the future to study how transcription, rRNA processing, cellular factors, and the native cellular environment shape ribosome assembly and RNP assembly at large.
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Affiliation(s)
- Kavan Gor
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
- Faculty of Biosciences, Collaboration for Joint PhD Degree between EMBL and Heidelberg University, 69117 Heidelberg, Germany
| | - Olivier Duss
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
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17
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Bohnsack KE, Henras AK, Nielsen H, Bohnsack MT. Making ends meet: a universal driver of large ribosomal subunit biogenesis. Trends Biochem Sci 2023; 48:213-215. [PMID: 36207216 DOI: 10.1016/j.tibs.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/10/2022] [Accepted: 09/14/2022] [Indexed: 11/07/2022]
Abstract
A common aspect of ribosome assembly, conserved across all domains of life, is the establishment of connections between the 5' and 3' ends of the large subunit (LSU) ribosomal RNA (rRNA) to initiate rRNA domain compaction and subunit assembly. We discuss the diverse mechanisms employed in different organisms to accomplish this important event.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, Göttingen, Germany.
| | - Anthony K Henras
- Molecular, Cellular and Developmental Biology Unit, University of Toulouse, Toulouse, France
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, Göttingen, Germany; Göttingen Center for Molecular Biosciences, Georg-August University, Göttingen, Germany.
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18
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Kinman LF, Powell BM, Zhong ED, Berger B, Davis JH. Uncovering structural ensembles from single-particle cryo-EM data using cryoDRGN. Nat Protoc 2023; 18:319-339. [PMID: 36376590 PMCID: PMC10049411 DOI: 10.1038/s41596-022-00763-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 07/21/2022] [Indexed: 11/16/2022]
Abstract
Single-particle cryogenic electron microscopy (cryo-EM) has emerged as a powerful technique to visualize the structural landscape sampled by a protein complex. However, algorithmic and computational bottlenecks in analyzing heterogeneous cryo-EM datasets have prevented the full realization of this potential. CryoDRGN is a machine learning system for heterogeneous cryo-EM reconstruction of proteins and protein complexes from single-particle cryo-EM data. Central to this approach is a deep generative model for heterogeneous cryo-EM density maps, which we empirically find is effective in modeling both discrete and continuous forms of structural variability. Once trained, cryoDRGN is capable of generating an arbitrary number of 3D density maps, and thus interpreting the resulting ensemble is a challenge. Here, we showcase interactive and automated processing approaches for analyzing cryoDRGN results. Specifically, we detail a step-by-step protocol for the analysis of an existing assembling 50S ribosome dataset, including preparation of inputs, network training and visualization of the resulting ensemble of density maps. Additionally, we describe and implement methods to comprehensively analyze and interpret the distribution of volumes with the assistance of an associated atomic model. This protocol is appropriate for structural biologists familiar with processing single-particle cryo-EM datasets and with moderate experience navigating Python and Jupyter notebooks. It requires 3-4 days to complete. CryoDRGN is open source software that is freely available.
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Affiliation(s)
- Laurel F Kinman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Barrett M Powell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ellen D Zhong
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Computer Science, Princeton University, Princeton, NJ, USA.
| | - Bonnie Berger
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Joseph H Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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19
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Hadjeras L, Bouvier M, Canal I, Poljak L, Morin-Ogier Q, Froment C, Burlet-Schlitz O, Hamouche L, Girbal L, Cocaign-Bousquet M, Carpousis AJ. Attachment of the RNA degradosome to the bacterial inner cytoplasmic membrane prevents wasteful degradation of rRNA in ribosome assembly intermediates. PLoS Biol 2023; 21:e3001942. [PMID: 36603027 PMCID: PMC9848016 DOI: 10.1371/journal.pbio.3001942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/18/2023] [Accepted: 12/01/2022] [Indexed: 01/06/2023] Open
Abstract
RNA processing and degradation shape the transcriptome by generating stable molecules that are necessary for translation (rRNA and tRNA) and by facilitating the turnover of mRNA, which is necessary for the posttranscriptional control of gene expression. In bacteria and the plant chloroplast, RNA degradosomes are multienzyme complexes that process and degrade RNA. In many bacterial species, the endoribonuclease RNase E is the central component of the RNA degradosome. RNase E-based RNA degradosomes are inner membrane proteins in a large family of gram-negative bacteria (β- and γ-Proteobacteria). Until now, the reason for membrane localization was not understood. Here, we show that a mutant strain of Escherichia coli, in which the RNA degradosome is localized to the interior of the cell, has high levels of 20S and 40S particles that are defective intermediates in ribosome assembly. These particles have aberrant protein composition and contain rRNA precursors that have been cleaved by RNase E. After RNase E cleavage, rRNA fragments are degraded to nucleotides by exoribonucleases. In vitro, rRNA in intact ribosomes is resistant to RNase E cleavage, whereas protein-free rRNA is readily degraded. We conclude that RNA degradosomes in the nucleoid of the mutant strain interfere with cotranscriptional ribosome assembly. We propose that membrane-attached RNA degradosomes in wild-type cells control the quality of ribosome assembly after intermediates are released from the nucleoid. That is, the compact structure of mature ribosomes protects rRNA against cleavage by RNase E. Turnover of a proportion of intermediates in ribosome assembly explains slow growth of the mutant strain. Competition between mRNA and rRNA degradation could be the cause of slower mRNA degradation in the mutant strain. We conclude that attachment of the RNA degradosome to the bacterial inner cytoplasmic membrane prevents wasteful degradation of rRNA precursors, thus explaining the reason for conservation of membrane-attached RNA degradosomes throughout the β- and γ-Proteobacteria.
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Affiliation(s)
- Lydia Hadjeras
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France
| | - Marie Bouvier
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France
| | - Isabelle Canal
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France
| | - Leonora Poljak
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France
| | | | - Carine Froment
- IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Infrastructure Nationale de Protéomique, ProFI, Toulouse, France
| | - Odile Burlet-Schlitz
- IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Infrastructure Nationale de Protéomique, ProFI, Toulouse, France
| | - Lina Hamouche
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France
| | - Laurence Girbal
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | | | - Agamemnon J. Carpousis
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- * E-mail:
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20
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Mechanisms and players of mitoribosomal biogenesis revealed in trypanosomatids. Trends Parasitol 2022; 38:1053-1067. [PMID: 36075844 DOI: 10.1016/j.pt.2022.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/29/2022] [Accepted: 08/16/2022] [Indexed: 01/13/2023]
Abstract
Translation in mitochondria is mediated by mitochondrial ribosomes, or mitoribosomes, complex ribonucleoprotein machines with dual genetic origin. Mitoribosomes in trypanosomatid parasites diverged markedly from their bacterial ancestors and other eukaryotic lineages in terms of protein composition, rRNA content, and overall architecture, yet their core functional elements remained conserved. Recent cryo-electron microscopy studies provided atomic models of trypanosomatid large and small mitoribosomal subunits and their precursors, making these parasites the organisms with the best-understood biogenesis of mitoribosomes. The structures revealed molecular mechanisms and players involved in the assembly of mitoribosomes not only in the parasites, but also in eukaryotes in general.
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21
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Chihara K, Gerovac M, Hör J, Vogel J. Global profiling of the RNA and protein complexes of Escherichia coli by size exclusion chromatography followed by RNA sequencing and mass spectrometry (SEC-seq). RNA (NEW YORK, N.Y.) 2022; 29:rna.079439.122. [PMID: 36328526 PMCID: PMC9808575 DOI: 10.1261/rna.079439.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
New methods for the global identification of RNA-protein interactions have led to greater recognition of the abundance and importance of RNA-binding proteins (RBPs) in bacteria. Here, we expand this tool kit by developing SEC-seq, a method based on a similar concept as the established Grad-seq approach. In Grad-seq, cellular RNA and protein complexes of a bacterium of interest are separated in a glycerol gradient, followed by high-throughput RNA-sequencing and mass spectrometry analyses of individual gradient fractions. New RNA-protein complexes are predicted based on the similarity of their elution profiles. In SEC-seq, we have replaced the glycerol gradient with separation by size exclusion chromatography, which shortens operation times and offers greater potential for automation. Applying SEC-seq to Escherichia coli, we find that the method provides a higher resolution than Grad-seq in the lower molecular weight range up to ~500 kDa. This is illustrated by the ability of SEC-seq to resolve two distinct, but similarly sized complexes of the global translational repressor CsrA with either of its antagonistic small RNAs, CsrB and CsrC. We also characterized changes in the SEC-seq profiles of the small RNA MicA upon deletion of its RNA chaperones Hfq and ProQ and investigated the redistribution of these two proteins upon RNase treatment. Overall, we demonstrate that SEC-seq is a tractable and reproducible method for the global profiling of bacterial RNA-protein complexes that offers the potential to discover yet-unrecognized associations between bacterial RNAs and proteins.
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Affiliation(s)
- Kotaro Chihara
- Helmholtz Institute for RNA-based Infection Research, Würzburg, Germany
| | | | - Jens Hör
- Weizmann Institute, Rehovot, Israel
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22
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Fatkhullin B, Golubev A, Garaeva N, Validov S, Gabdulkhakov A, Yusupov M. Y98 Mutation Leads to the Loss of RsfS Anti-Association Activity in Staphylococcus aureus. Int J Mol Sci 2022; 23:ijms231810931. [PMID: 36142845 PMCID: PMC9503621 DOI: 10.3390/ijms231810931] [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] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/08/2022] [Accepted: 09/15/2022] [Indexed: 11/29/2022] Open
Abstract
Ribosomal silencing factor S (RsfS) is a conserved protein that plays a role in the mechanisms of ribosome shutdown and cell survival during starvation. Recent studies demonstrated the involvement of RsfS in the biogenesis of the large ribosomal subunit. RsfS binds to the uL14 ribosomal protein on the large ribosomal subunit and prevents its association with the small subunit. Here, we estimated the contribution of RsfS amino acid side chains at the interface between RsfS and uL14 to RsfS anti-association function in Staphylococcus aureus through in vitro experiments: centrifugation in sucrose gradient profiles and an S. aureus cell-free system assay. The detected critical Y98 amino acid on the RsfS surface might become a new potential target for pharmacological drug development and treatment of S. aureus infections.
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Affiliation(s)
- Bulat Fatkhullin
- Institute of Protein Research, Russian Academy of Science, 142290 Pushchino, Russia
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964, CNRS, UMR7104, University of Strasbourg, 67400 Illkirch Graffenstaden, France
| | - Alexander Golubev
- Laboratory for Structural Analysis of Biomacromolecules, Kazan Scientific Center of Russian Academy of Sciences, 420111 Kazan, Russia
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
| | - Natalia Garaeva
- Laboratory for Structural Analysis of Biomacromolecules, Kazan Scientific Center of Russian Academy of Sciences, 420111 Kazan, Russia
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
| | - Shamil Validov
- Laboratory for Structural Analysis of Biomacromolecules, Kazan Scientific Center of Russian Academy of Sciences, 420111 Kazan, Russia
| | - Azat Gabdulkhakov
- Institute of Protein Research, Russian Academy of Science, 142290 Pushchino, Russia
| | - Marat Yusupov
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, INSERM, U964, CNRS, UMR7104, University of Strasbourg, 67400 Illkirch Graffenstaden, France
- Laboratory for Structural Analysis of Biomacromolecules, Kazan Scientific Center of Russian Academy of Sciences, 420111 Kazan, Russia
- Correspondence:
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23
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Naganathan A, Culver GM. Interdependency and Redundancy Add Complexity and Resilience to Biogenesis of Bacterial Ribosomes. Annu Rev Microbiol 2022; 76:193-210. [PMID: 35609945 DOI: 10.1146/annurev-micro-041020-121806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The pace and efficiency of ribosomal subunit production directly impact the fitness of bacteria. Biogenesis demands more than just the union of ribosomal components, including RNA and proteins, to form this functional ribonucleoprotein particle. Extra-ribosomal protein factors play a fundamental role in the efficiency and efficacy of ribosomal subunit biogenesis. A paucity of data on intermediate steps, multiple and overlapping pathways, and the puzzling number of functions that extra-ribosomal proteins appear to play in vivo make unraveling the formation of this macromolecular assemblage difficult. In this review, we outline with examples the multinodal landscape of factor-assisted mechanisms that influence ribosome synthesis in bacteria. We discuss in detail late-stage events that mediate correct ribosome formation and the transition to translation initiation and thereby ensure high-fidelity protein synthesis.
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Affiliation(s)
- Anusha Naganathan
- Department of Biology, University of Rochester, Rochester, New York, USA; ,
| | - Gloria M Culver
- Department of Biology, University of Rochester, Rochester, New York, USA; ,
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York, USA
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24
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Duplicated ribosomal protein paralogs promote alternative translation and drug resistance. Nat Commun 2022; 13:4938. [PMID: 35999447 PMCID: PMC9399092 DOI: 10.1038/s41467-022-32717-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 08/12/2022] [Indexed: 11/28/2022] Open
Abstract
Ribosomes are often seen as monolithic machines produced from uniformly regulated genes. However, in yeast most ribosomal proteins come from duplicated genes. Here, we demonstrate that gene duplication may serve as a stress-adaptation mechanism modulating the global proteome through the differential expression of ribosomal protein paralogs. Our data indicate that the yeast paralog pair of the ribosomal protein L7/uL30 produces two differentially acetylated proteins. Under normal conditions most ribosomes incorporate the hypo-acetylated major form favoring the translation of genes with short open reading frames. Exposure to drugs, on the other hand, increases the production of ribosomes carrying the hyper-acetylated minor paralog that increases translation of long open reading frames. Many of these paralog-dependent genes encode cell wall proteins that could promote tolerance to drugs as their translation increases after exposure to drugs. Together our data suggest a mechanism of translation control that functions through a differential use of near-identical ribosomal protein isoforms. Most yeast ribosomal protein genes are duplicated but the functional significance of this duplication remains unclear. This study identifies a natural program where changing the ratio of proteins produced from duplicated genes modifies translation in response to drugs regardless of ribosome number.
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25
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Solov'yov IA, Sushko G, Friis I, Solov'yov AV. Multiscale modeling of stochastic dynamics processes with MBN Explorer. J Comput Chem 2022; 43:1442-1458. [PMID: 35708151 DOI: 10.1002/jcc.26948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/25/2022] [Accepted: 05/29/2022] [Indexed: 11/09/2022]
Abstract
Stochastic dynamics describes processes in complex systems having the probabilistic nature. They can involve very different dynamical systems and occur on very different temporal and spatial scale. This paper discusses the concept of stochastic dynamics and its implementation in the popular program MBN Explorer. Stochastic dynamics in MBN Explorer relies on the Monte Carlo approach and permits simulations of physical, chemical, and biological processes. The paper presents the basic theoretical concepts underlying stochastic dynamics implementation and provides several examples highlighting its applicability to different systems, such as diffusing proteins seeking an anchor point on a cell membrane, deposition of nanoparticles on a surface leading to structures with fractal morphologies, and oscillations of compounds in an autocatalytic reaction. The chosen examples illustrate the diversity of applications that can be modeled by means of stochastic dynamics with MBN Explorer.
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Affiliation(s)
- Ilia A Solov'yov
- Department of Physics, Carl von Ossietzky University, Oldenburg, Germany.,Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.,Center for Nanoscale Dynamics (CENAD), Institut für Physik, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | | | - Ida Friis
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark
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26
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Macromolecular Structure Assembly as a Novel Antibiotic Target. Antibiotics (Basel) 2022; 11:antibiotics11070937. [PMID: 35884191 PMCID: PMC9311618 DOI: 10.3390/antibiotics11070937] [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: 05/03/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 12/03/2022] Open
Abstract
This review discusses the inhibition of macromolecular structure formation as a novel and under-investigated drug target. The disruption of cell wall structures by penicillin-binding protein interactions is one potential target. Inhibition of DNA polymerase III assembly by novel drugs is a second target that should be investigated. RNA polymerase protein structural interactions are a third potential target. Finally, disruption of ribosomal subunit biogenesis represents a fourth important target that can be further investigated. Methods to examine these possibilities are discussed.
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27
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Lin S, Rajan S, Lemberg S, Altawil M, Anderson K, Bryant R, Cappeta S, Chin B, Hamdan I, Hamer A, Hyzny R, Karp A, Lee D, Lim A, Nayak M, Palaniappan V, Park S, Satishkumar S, Seth A, Sri Dasari U, Toppari E, Vyas A, Walker J, Weston E, Zafar A, Zielke C, Mahabeleshwar GH, Tartakoff AM. Production of nascent ribosome precursors within the nucleolar microenvironment of Saccharomyces cerevisiae. Genetics 2022; 221:iyac070. [PMID: 35657327 PMCID: PMC9252279 DOI: 10.1093/genetics/iyac070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
35S rRNA transcripts include a 5'-external transcribed spacer followed by rRNAs of the small and large ribosomal subunits. Their processing yields massive precursors that include dozens of assembly factor proteins. In Saccharomyces cerevisiae, nucleolar assembly factors form 2 coaxial layers/volumes around ribosomal DNA. Most of these factors are cyclically recruited from a latent state to an operative state, and are extensively conserved. The layers match, at least approximately, known subcompartments found in higher eukaryotic cells. ∼80% of assembly factors are essential. The number of copies of these assembly factors is comparable to the number of nascent transcripts. Moreover, they exhibit "isoelectric balance," with RNA-binding candidate "nucleator" assembly factors being notably basic. The physical properties of pre-small subunit and pre-large subunit assembly factors are similar, as are their 19 motif signatures detected by hierarchical clustering, unlike motif signatures of the 5'-external transcribed spacer rRNP. Additionally, many assembly factors lack shared motifs. Taken together with the progression of rRNP composition during subunit maturation, and the realization that the ribosomal DNA cable is initially bathed in a subunit-nonspecific assembly factor reservoir/microenvironment, we propose a "3-step subdomain assembly model": Step (1): predominantly basic assembly factors sequentially nucleate sites along nascent rRNA; Step (2): the resulting rRNPs recruit numerous less basic assembly factors along with notably basic ribosomal proteins; Step (3): rRNPs in nearby subdomains consolidate. Cleavages of rRNA then promote release of rRNPs to the nucleoplasm, likely facilitated by the persistence of assembly factors that were already associated with nucleolar precursors.
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Affiliation(s)
- Samantha Lin
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Suchita Rajan
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sofia Lemberg
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Mark Altawil
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Katherine Anderson
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ruth Bryant
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sebastian Cappeta
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Brandon Chin
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Isabella Hamdan
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Annelise Hamer
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Rachel Hyzny
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Andrew Karp
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Daniel Lee
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Alexandria Lim
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Medha Nayak
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Vishnu Palaniappan
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Soomin Park
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sarika Satishkumar
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Anika Seth
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Uva Sri Dasari
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Emili Toppari
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ayush Vyas
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Julianne Walker
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Evan Weston
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Atif Zafar
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Cecelia Zielke
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ganapati H Mahabeleshwar
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Alan M Tartakoff
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
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Bhujbalrao R, Gavvala K, Singh RK, Singh J, Boudier C, Chakrabarti S, Patwari GN, Mély Y, Anand R. Identification of Allosteric Hotspots regulating the ribosomal RNA-binding by Antibiotic Resistance-Conferring Erm Methyltransferases. J Biol Chem 2022; 298:102208. [PMID: 35772496 PMCID: PMC9386465 DOI: 10.1016/j.jbc.2022.102208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/12/2022] Open
Abstract
Antibiotic resistance via epigenetic methylation of ribosomal RNA is one of the most prevalent strategies adopted by multidrug resistant pathogens. The erythromycin-resistance methyltransferase (Erm) methylates rRNA at the conserved A2058 position and imparts resistance to macrolides such as erythromycin. However, the precise mechanism adopted by Erm methyltransferases for locating the target base within a complicated rRNA scaffold remains unclear. Here, we show that a conserved RNA architecture, including specific bulge sites, present more than 15 Å from the reaction center, is key to methylation at the pathogenic site. Using a set of RNA sequences site-specifically labeled by fluorescent nucleotide surrogates, we show that base flipping is a prerequisite for effective methylation and that distal bases assist in the recognition and flipping at the reaction center. The Erm–RNA complex model revealed that intrinsically flipped-out bases in the RNA serve as a putative anchor point for the Erm. Molecular dynamic simulation studies demonstrated the RNA undergoes a substantial change in conformation to facilitate an effective protein–rRNA handshake. This study highlights the importance of unique architectural features exploited by RNA to impart fidelity to RNA methyltransferases via enabling allosteric crosstalk. Moreover, the distal trigger sites identified here serve as attractive hotspots for the development of combination drug therapy aimed at reversing resistance.
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Affiliation(s)
- Ruchika Bhujbalrao
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Krishna Gavvala
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401 Illkirch, France
| | - Reman Kumar Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Juhi Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Christian Boudier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401 Illkirch, France
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195 Berlin, Germany
| | - G Naresh Patwari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401 Illkirch, France.
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; Wellcome Trust DBT Indian Alliance Senior Fellow.
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29
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Carpousis AJ, Campo N, Hadjeras L, Hamouche L. Compartmentalization of RNA Degradosomes in Bacteria Controls Accessibility to Substrates and Ensures Concerted Degradation of mRNA to Nucleotides. Annu Rev Microbiol 2022; 76:533-552. [PMID: 35671533 DOI: 10.1146/annurev-micro-041020-113308] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA degradosomes are multienzyme complexes composed of ribonucleases, RNA helicases, and metabolic enzymes. RNase E-based degradosomes are widespread in Proteobacteria. The Escherichia coli RNA degradosome is sequestered from transcription in the nucleoid and translation in the cytoplasm by localization to the inner cytoplasmic membrane, where it forms short-lived clusters that are proposed to be sites of mRNA degradation. In Caulobacter crescentus, RNA degradosomes localize to ribonucleoprotein condensates in the interior of the cell [bacterial ribonucleoprotein-bodies (BR-bodies)], which have been proposed to drive the concerted degradation of mRNA to nucleotides. The turnover of mRNA in growing cells is important for maintaining pools of nucleotides for transcription and DNA replication. Membrane attachment of the E. coli RNA degradosome is necessary to avoid wasteful degradation of intermediates in ribosome assembly. Sequestering RNA degradosomes to C. crescentus BR-bodies, which exclude structured RNA, could have a similar role in protecting intermediates in ribosome assembly from degradation. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Agamemnon J Carpousis
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France; , , .,TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Nathalie Campo
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France; , ,
| | - Lydia Hadjeras
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France; , , .,Current affiliation: IMIB, University of Würzburg, Würzburg, Germany;
| | - Lina Hamouche
- LMGM, Université de Toulouse, CNRS, UPS, CBI, Toulouse, France; , ,
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30
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Singh J, Raina R, Vinothkumar KR, Anand R. Decoding the Mechanism of Specific RNA Targeting by Ribosomal Methyltransferases. ACS Chem Biol 2022; 17:829-839. [PMID: 35316014 DOI: 10.1021/acschembio.1c00732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Methylation of specific nucleotides is integral for ribosomal biogenesis and also serves as a common mechanism to confer antibiotic resistance by pathogenic bacteria. Here, by determining the high-resolution structure of the 30S-KsgA complex by cryo-electron microscopy, a state was captured, where KsgA juxtaposes between helices h44 and h45 of the 30S ribosome, separating them, thereby enabling remodeling of the surrounded rRNA and allowing the cognate site to enter the methylation pocket. With the structure as a guide, several mutant versions of the ribosomes, where interacting bases in the catalytic helix h45 and surrounding helices h44, h24, and h27, were mutated and evaluated for their methylation efficiency revealing factors that direct the enzyme to its cognate site with high fidelity. The biochemical studies show that the three-dimensional environment of the ribosome enables the interaction of select loop regions in KsgA with the ribosome helices paramount to maintain selectivity.
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Affiliation(s)
- Juhi Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India
| | - Rahul Raina
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru560065, India
| | - Kutti R. Vinothkumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru560065, India
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India
- DBT-Wellcome Trust India Alliance Senior Fellow, Mumbai400076, India
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31
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How to save a bacterial ribosome in times of stress. Semin Cell Dev Biol 2022; 136:3-12. [PMID: 35331628 DOI: 10.1016/j.semcdb.2022.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/01/2022] [Accepted: 03/11/2022] [Indexed: 11/21/2022]
Abstract
Biogenesis of ribosomes is one of the most cost- and resource-intensive processes in all living cells. In bacteria, ribosome biogenesis is rate-limiting for growth and must be tightly coordinated to yield maximum fitness of the cells. Since bacteria are continuously facing environmental changes and stress conditions, they have developed sophisticated systems to sense and regulate their nutritional status. Amino acid starvation leads to the synthesis and accumulation of the nucleotide-based second messengers ppGpp and pppGpp [(p)ppGpp], which in turn function as central players of a pleiotropic metabolic adaptation mechanism named the stringent response. Here, we review our current knowledge on the multiple roles of (p)ppGpp in the stress-related modulation of the prokaryotic protein biosynthesis machinery with the ribosome as its core constituent. The alarmones ppGpp/pppGpp act as competitors of their GDP/GTP counterparts, to affect a multitude of ribosome-associated P-loop GTPases involved in the translation cycle, ribosome biogenesis and hibernation. A similar mode of inhibition has been found for the GTPases of the proteins involved in the SRP-dependent membrane-targeting machinery present in the periphery of the ribosome. In this sense, during stringent conditions, binding of (p)ppGpp restricts the membrane insertion and secretion of proteins. Altogether, we highlight the enormously resource-intensive stages of ribosome biogenesis as a critical regulatory hub of the stringent response that ultimately tunes the protein synthesis capacity and consequently the survival of the cell.
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32
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Jüttner M, Ferreira-Cerca S. Looking through the lens of the ribosome biogenesis evolutionary history: possible implications for archaeal phylogeny and eukaryogenesis. Mol Biol Evol 2022; 39:6547259. [PMID: 35275997 PMCID: PMC8997704 DOI: 10.1093/molbev/msac054] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Our understanding of microbial diversity and its evolutionary relationships has increased substantially over the last decade. Such an understanding has been greatly fueled by culture-independent metagenomics analyses. However, the outcome of some of these studies and their biological and evolutionary implications, such as the origin of the eukaryotic lineage from the recently discovered archaeal Asgard superphylum, is debated. The sequences of the ribosomal constituents are amongst the most used phylogenetic markers. However, the functional consequences underlying the analysed sequence diversity and their putative evolutionary implications are essentially not taken into consideration. Here, we propose to exploit additional functional hallmarks of ribosome biogenesis to help disentangle competing evolutionary hypotheses. Using selected examples, such as the multiple origins of halophily in archaea or the evolutionary relationship between the Asgard archaea and Eukaryotes, we illustrate and discuss how function-aware phylogenetic framework can contribute to refining our understanding of archaeal phylogeny and the origin of eukaryotic cells.
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Affiliation(s)
- Michael Jüttner
- Regensburg Center for Biochemistry, Biochemistry III - Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Sébastien Ferreira-Cerca
- Regensburg Center for Biochemistry, Biochemistry III - Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
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33
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Harmon TS, Jülicher F. Molecular Assembly Lines in Active Droplets. PHYSICAL REVIEW LETTERS 2022; 128:108102. [PMID: 35333067 DOI: 10.1103/physrevlett.128.108102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 11/30/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Large protein complexes are assembled from protein subunits to form a specific structure. In our theoretic work, we propose that assembly into the correct structure could be reliably achieved through an assembly line with a specific sequence of assembly steps. Using droplet interfaces to position compartment boundaries, we show that an assembly line can be self-organized by active droplets. As a consequence, assembly steps can be arranged spatially so that a specific order of assembly is achieved and incorrect assembly is strongly suppressed.
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Affiliation(s)
- Tyler S Harmon
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzerstraße 38, 01187 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohestraße 6, 01069 Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzerstraße 38, 01187 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01062 Dresden, Germany
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34
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Nemashkalo A, Phipps ME, Hennelly SP, Goodwin PM. Real-time, single-molecule observation of biomolecular interactions inside nanophotonic zero mode waveguides. NANOTECHNOLOGY 2022; 33:165101. [PMID: 34959227 DOI: 10.1088/1361-6528/ac467c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Living cells rely on numerous protein-protein, RNA-protein and DNA-protein interactions for processes such as gene expression, biomolecular assembly, protein and RNA degradation. Single-molecule microscopy and spectroscopy are ideal tools for real-time observation and quantification of nucleic acids-protein and protein-protein interactions. One of the major drawbacks of conventional single-molecule imaging methods is low throughput. Methods such as sequencing by synthesis utilizing nanofabrication and single-molecule spectroscopy have brought high throughput into the realm of single-molecule biology. The Pacific Biosciences RS2 sequencer utilizes sequencing by synthesis within nanophotonic zero mode waveguides. A number of years ago this instrument was unlocked by Pacific Biosciences for custom use by researchers allowing them to monitor biological interactions at the single-molecule level with high throughput. In this capability letter we demonstrate the use of the RS2 sequencer for real-time observation of DNA-to-RNA transcription and RNA-protein interactions. We use a relatively complex model-transcription of structured ribosomal RNA fromE. coliand interactions of ribosomal RNA with ribosomal proteins. We also show evidence of observation of transcriptional pausing without the application of an external force (as is required for single-molecule pausing studies using optical traps). Overall, in the unlocked, custom mode, the RS2 sequencer can be used to address a wide variety of biological assembly and interaction questions at the single-molecule level with high throughput. This instrument is available for use at the Center for Integrated Nanotechnologies Gateway located at Los Alamos National Laboratory.
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Affiliation(s)
- A Nemashkalo
- MPA-CINT (Materials Physics and Applications, Center for Integrated Nanotechnologies, Los Alamos National Laboratory), United States of America
| | - M E Phipps
- MPA-CINT (Materials Physics and Applications, Center for Integrated Nanotechnologies, Los Alamos National Laboratory), United States of America
| | - S P Hennelly
- B-11 (Bioenergy and Biome Sciences, Los Alamos National Laboratory), United States of America
| | - P M Goodwin
- MPA-CINT (Materials Physics and Applications, Center for Integrated Nanotechnologies, Los Alamos National Laboratory), United States of America
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35
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Aviram N, Thornal AN, Zeevi D, Marraffini LA. Different modes of spacer acquisition by the Staphylococcus epidermidis type III-A CRISPR-Cas system. Nucleic Acids Res 2022; 50:1661-1672. [PMID: 35048966 PMCID: PMC8860600 DOI: 10.1093/nar/gkab1299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/15/2021] [Accepted: 01/06/2022] [Indexed: 12/23/2022] Open
Abstract
CRISPR-Cas systems provide prokaryotic organisms with an adaptive defense mechanism that acquires immunological memories of infections. This is accomplished by integration of short fragments from the genome of invaders such as phages and plasmids, called ‘spacers’, into the CRISPR locus of the host. Depending on their genetic composition, CRISPR-Cas systems can be classified into six types, I-VI, however spacer acquisition has been extensively studied only in type I and II systems. Here, we used an inducible spacer acquisition assay to study this process in the type III-A CRISPR-Cas system of Staphylococcus epidermidis, in the absence of phage selection. Similarly to type I and II spacer acquisition, this type III system uses Cas1 and Cas2 to preferentially integrate spacers from the chromosomal terminus and free dsDNA ends produced after DNA breaks, in a manner that is enhanced by the AddAB DNA repair complex. Surprisingly, a different mode of spacer acquisition from rRNA and tRNA loci, which spans only the transcribed sequences of these genes and is not enhanced by AddAB, was also detected. Therefore, our findings reveal both common mechanistic principles that may be conserved in all CRISPR-Cas systems, as well as unique and intriguing features of type III spacer acquisition.
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Affiliation(s)
- Naama Aviram
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Ashley N Thornal
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - David Zeevi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Luciano A Marraffini
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA.,Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
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36
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Lenarčič T, Niemann M, Ramrath DJF, Calderaro S, Flügel T, Saurer M, Leibundgut M, Boehringer D, Prange C, Horn EK, Schneider A, Ban N. Mitoribosomal small subunit maturation involves formation of initiation-like complexes. Proc Natl Acad Sci U S A 2022; 119:e2114710118. [PMID: 35042777 PMCID: PMC8784144 DOI: 10.1073/pnas.2114710118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/29/2021] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial ribosomes (mitoribosomes) play a central role in synthesizing mitochondrial inner membrane proteins responsible for oxidative phosphorylation. Although mitoribosomes from different organisms exhibit considerable structural variations, recent insights into mitoribosome assembly suggest that mitoribosome maturation follows common principles and involves a number of conserved assembly factors. To investigate the steps involved in the assembly of the mitoribosomal small subunit (mt-SSU) we determined the cryoelectron microscopy structures of middle and late assembly intermediates of the Trypanosoma brucei mitochondrial small subunit (mt-SSU) at 3.6- and 3.7-Å resolution, respectively. We identified five additional assembly factors that together with the mitochondrial initiation factor 2 (mt-IF-2) specifically interact with functionally important regions of the rRNA, including the decoding center, thereby preventing premature mRNA or large subunit binding. Structural comparison of assembly intermediates with mature mt-SSU combined with RNAi experiments suggests a noncanonical role of mt-IF-2 and a stepwise assembly process, where modular exchange of ribosomal proteins and assembly factors together with mt-IF-2 ensure proper 9S rRNA folding and protein maturation during the final steps of assembly.
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Affiliation(s)
- Tea Lenarčič
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Moritz Niemann
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - David J F Ramrath
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Salvatore Calderaro
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Timo Flügel
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Martin Saurer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Céline Prange
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Elke K Horn
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - André Schneider
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland;
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37
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Jüttner M, Ferreira-Cerca S. A Comparative Perspective on Ribosome Biogenesis: Unity and Diversity Across the Tree of Life. Methods Mol Biol 2022; 2533:3-22. [PMID: 35796979 PMCID: PMC9761495 DOI: 10.1007/978-1-0716-2501-9_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Ribosomes are universally conserved ribonucleoprotein complexes involved in the decoding of the genetic information contained in messenger RNAs into proteins. Accordingly, ribosome biogenesis is a fundamental cellular process required for functional ribosome homeostasis and to preserve satisfactory gene expression capability.Although the ribosome is universally conserved, its biogenesis shows an intriguing degree of variability across the tree of life . These differences also raise yet unresolved questions. Among them are (a) what are, if existing, the remaining ancestral common principles of ribosome biogenesis ; (b) what are the molecular impacts of the evolution history and how did they contribute to (re)shape the ribosome biogenesis pathway across the tree of life ; (c) what is the extent of functional divergence and/or convergence (functional mimicry), and in the latter case (if existing) what is the molecular basis; (d) considering the universal ribosome conservation, what is the capability of functional plasticity and cellular adaptation of the ribosome biogenesis pathway?In this review, we provide a brief overview of ribosome biogenesis across the tree of life and try to illustrate some potential and/or emerging answers to these unresolved questions.
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Affiliation(s)
- Michael Jüttner
- Biochemistry III-Regensburg Center for Biochemistry-Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Sébastien Ferreira-Cerca
- Biochemistry III-Regensburg Center for Biochemistry-Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany.
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38
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Leroux M, Soubry N, Reyes-Lamothe R. Dynamics of Proteins and Macromolecular Machines in Escherichia coli. EcoSal Plus 2021; 9:eESP00112020. [PMID: 34060908 PMCID: PMC11163846 DOI: 10.1128/ecosalplus.esp-0011-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/16/2021] [Indexed: 11/20/2022]
Abstract
Proteins are major contributors to the composition and the functions in the cell. They often assemble into larger structures, macromolecular machines, to carry out intricate essential functions. Although huge progress in understanding how macromolecular machines function has been made by reconstituting them in vitro, the role of the intracellular environment is still emerging. The development of fluorescence microscopy techniques in the last 2 decades has allowed us to obtain an increased understanding of proteins and macromolecular machines in cells. Here, we describe how proteins move by diffusion, how they search for their targets, and how they are affected by the intracellular environment. We also describe how proteins assemble into macromolecular machines and provide examples of how frequent subunit turnover is used for them to function and to respond to changes in the intracellular conditions. This review emphasizes the constant movement of molecules in cells, the stochastic nature of reactions, and the dynamic nature of macromolecular machines.
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Affiliation(s)
- Maxime Leroux
- Department of Biology, McGill University, Montreal, QC, Canada
| | - Nicolas Soubry
- Department of Biology, McGill University, Montreal, QC, Canada
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Aoyama R, Masuda K, Shimojo M, Kanamori T, Ueda T, Shimizu Y. In vitro reconstitution of the Escherichia coli 70S ribosome with a full set of recombinant ribosomal proteins. J Biochem 2021; 171:227-237. [PMID: 34750629 PMCID: PMC8863084 DOI: 10.1093/jb/mvab121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/04/2021] [Indexed: 11/27/2022] Open
Abstract
Many studies of the reconstitution of the Escherichia coli small ribosomal subunit from its individual molecular parts have been reported, but contrastingly, similar studies of the large ribosomal subunit have not been well performed to date. Here, we describe protocols for preparing the 33 ribosomal proteins of the E. coli 50S subunit and demonstrate successful reconstitution of a functionally active 50S particle that can perform protein synthesis in vitro. We also successfully reconstituted both ribosomal subunits (30S and 50S) and 70S ribosomes using a full set of recombinant ribosomal proteins by integrating our developed method with the previously developed fully recombinant-based integrated synthesis, assembly and translation. The approach described here makes a major contribution to the field of ribosome engineering and could be fundamental to the future studies of ribosome assembly processes.
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Affiliation(s)
- Ryo Aoyama
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Keiko Masuda
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan
| | - Masaru Shimojo
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | | | - Takuya Ueda
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan.,Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, Shinjuku, Tokyo 162-8480, Japan
| | - Yoshihiro Shimizu
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan
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40
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Abstract
To exert their functions, RNAs adopt diverse structures, ranging from simple secondary to complex tertiary and quaternary folds. In vivo, RNA folding starts with RNA transcription, and a wide variety of processes are coupled to co-transcriptional RNA folding events, including the regulation of fundamental transcription dynamics, gene regulation by mechanisms like attenuation, RNA processing or ribonucleoprotein particle formation. While co-transcriptional RNA folding and associated co-transcriptional processes are by now well accepted as pervasive regulatory principles in all organisms, investigations into the role of the transcription machinery in co-transcriptional folding processes have so far largely focused on effects of the order in which RNA regions are produced and of transcription kinetics. Recent structural and structure-guided functional analyses of bacterial transcription complexes increasingly point to an additional role of RNA polymerase and associated transcription factors in supporting co-transcriptional RNA folding by fostering or preventing strategic contacts to the nascent transcripts. In general, the results support the view that transcription complexes can act as RNA chaperones, a function that has been suggested over 30 years ago. Here, we discuss transcription complexes as RNA chaperones based on recent examples from bacterial transcription.
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Affiliation(s)
- Nelly Said
- Freie Universität Berlin, Department Biology, Chemistry, Pharmacy, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany
| | - Markus C Wahl
- Freie Universität Berlin, Department Biology, Chemistry, Pharmacy, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany.,Helmholtz-Zentrum Berlin Für Materialien Und Energie, Macromolecular Crystallography, Berlin, Germany
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41
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Masuda K, Kasahara K, Narumi R, Shimojo M, Shimizu Y. Versatile and multiplexed mass spectrometry-based absolute quantification with cell-free-synthesized internal standard peptides. J Proteomics 2021; 251:104393. [PMID: 34678518 DOI: 10.1016/j.jprot.2021.104393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
Preparation of stable isotope-labeled internal standard peptides is crucial for mass spectrometry (MS)-based targeted proteomics. Herein, we developed versatile and multiplexed absolute protein quantification method using MS. A previously developed method based on the cell-free peptide synthesis system, termed MS-based quantification by isotope-labeled cell-free products (MS-QBiC), was improved for multiple peptide synthesis in one-pot reaction. We pluralized the quantification tags used for the quantification of synthesized peptides and thus, made it possible to use cell-free synthesized isotope-labeled peptides as mixtures for the absolute quantification. The improved multiplexed MS-QBiC method was proved to be applied to clarify ribosomal proteins stoichiometry in the ribosomal subunit, one of the largest cellular complexes. The study demonstrates that the developed method enables the preparation of several dozens and even several hundreds of internal standard peptides within a few days for quantification of multiple proteins with only a single-run of MS analysis. SIGNIFICANCE: The developed method can be applied for the preparation of internal standard peptides without limiting the number of peptides to be synthesized, which may result in more practical screening of quantitatively reliable peptides, one of the fundamental steps in the reliable absolute quantification using MS. Furthermore, the method is highly versatile for proteome analysis of any organisms or species without any cDNA or SIL peptide libraries. The quantification can be finished in a few days including design and preparation of appropriate SIL peptides using small-scale batch cell-free reactions, which has a potential to be a part of the standard methodology in a field of quantitative proteomics.
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Affiliation(s)
- Keiko Masuda
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka 565-0874, Japan
| | - Keiko Kasahara
- Department of Surgery, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Kyoto 606-8501, Japan; Laboratory of Proteome Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan
| | - Ryohei Narumi
- Laboratory of Proteome Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan
| | - Masaru Shimojo
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka 565-0874, Japan
| | - Yoshihiro Shimizu
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka 565-0874, Japan.
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42
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Shape changes and cooperativity in the folding of the central domain of the 16S ribosomal RNA. Proc Natl Acad Sci U S A 2021; 118:2020837118. [PMID: 33658370 DOI: 10.1073/pnas.2020837118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Both the small and large subunits of the ribosome, the molecular machine that synthesizes proteins, are complexes of ribosomal RNAs (rRNAs) and a number of proteins. In bacteria, the small subunit has a single 16S rRNA whose folding is the first step in its assembly. The central domain of the 16S rRNA folds independently, driven either by Mg2+ ions or by interaction with ribosomal proteins. To provide a quantitative description of ion-induced folding of the ∼350-nucleotide rRNA, we carried out extensive coarse-grained molecular simulations spanning Mg2+ concentration between 0 and 30 mM. The Mg2+ dependence of the radius of gyration shows that globally the rRNA folds cooperatively. Surprisingly, various structural elements order at different Mg2+ concentrations, indicative of the heterogeneous assembly even within a single domain of the rRNA. Binding of Mg2+ ions is highly specific, with successive ion condensation resulting in nucleation of tertiary structures. We also predict the Mg2+-dependent protection factors, measurable in hydroxyl radical footprinting experiments, which corroborate the specificity of Mg2+-induced folding. The simulations, which agree quantitatively with several experiments on the folding of a three-way junction, show that its folding is preceded by formation of other tertiary contacts in the central junction. Our work provides a starting point in simulating the early events in the assembly of the small subunit of the ribosome.
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Hilander T, Jackson CB, Robciuc M, Bashir T, Zhao H. The roles of assembly factors in mammalian mitoribosome biogenesis. Mitochondrion 2021; 60:70-84. [PMID: 34339868 DOI: 10.1016/j.mito.2021.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 02/08/2023]
Abstract
As ancient bacterial endosymbionts of eukaryotic cells, mitochondria have retained their own circular DNA as well as protein translation system including mitochondrial ribosomes (mitoribosomes). In recent years, methodological advancements in cryoelectron microscopy and mass spectrometry have revealed the extent of the evolutionary divergence of mitoribosomes from their bacterial ancestors and their adaptation to the synthesis of 13 mitochondrial DNA encoded oxidative phosphorylation complex subunits. In addition to the structural data, the first assembly pathway maps of mitoribosomes have started to emerge and concomitantly also the assembly factors involved in this process to achieve fully translational competent particles. These transiently associated factors assist in the intricate assembly process of mitoribosomes by enhancing protein incorporation, ribosomal RNA folding and modification, and by blocking premature or non-native protein binding, for example. This review focuses on summarizing the current understanding of the known mammalian mitoribosome assembly factors and discussing their possible roles in the assembly of small or large mitoribosomal subunits.
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Affiliation(s)
- Taru Hilander
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland.
| | - Christopher B Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Finland.
| | - Marius Robciuc
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Tanzeela Bashir
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Hongxia Zhao
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland; Key Laboratory of Stem Cell and Biopharmaceutical Technology, School of Life Sciences, Guangxi Normal University, Guangxi, China.
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44
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Cheng J, Berninghausen O, Beckmann R. A distinct assembly pathway of the human 39S late pre-mitoribosome. Nat Commun 2021; 12:4544. [PMID: 34315873 PMCID: PMC8316566 DOI: 10.1038/s41467-021-24818-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/01/2021] [Indexed: 02/03/2023] Open
Abstract
Assembly of the mitoribosome is largely enigmatic and involves numerous assembly factors. Little is known about their function and the architectural transitions of the pre-ribosomal intermediates. Here, we solve cryo-EM structures of the human 39S large subunit pre-ribosomes, representing five distinct late states. Besides the MALSU1 complex used as bait for affinity purification, we identify several assembly factors, including the DDX28 helicase, MRM3, GTPBP10 and the NSUN4-mTERF4 complex, all of which keep the 16S rRNA in immature conformations. The late transitions mainly involve rRNA domains IV and V, which form the central protuberance, the intersubunit side and the peptidyltransferase center of the 39S subunit. Unexpectedly, we find deacylated tRNA in the ribosomal E-site, suggesting a role in 39S assembly. Taken together, our study provides an architectural inventory of the distinct late assembly phase of the human 39S mitoribosome.
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Affiliation(s)
- Jingdong Cheng
- Gene Center and Department for Biochemistry, LMU Munich, München, Germany.
| | - Otto Berninghausen
- Gene Center and Department for Biochemistry, LMU Munich, München, Germany
| | - Roland Beckmann
- Gene Center and Department for Biochemistry, LMU Munich, München, Germany.
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45
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Londei P, Ferreira-Cerca S. Ribosome Biogenesis in Archaea. Front Microbiol 2021; 12:686977. [PMID: 34367089 PMCID: PMC8339473 DOI: 10.3389/fmicb.2021.686977] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 05/14/2021] [Indexed: 12/02/2022] Open
Abstract
Making ribosomes is a major cellular process essential for the maintenance of functional ribosome homeostasis and to ensure appropriate gene expression. Strikingly, although ribosomes are universally conserved ribonucleoprotein complexes decoding the genetic information contained in messenger RNAs into proteins, their biogenesis shows an intriguing degree of variability across the tree of life. In this review, we summarize our knowledge on the least understood ribosome biogenesis pathway: the archaeal one. Furthermore, we highlight some evolutionary conserved and divergent molecular features of making ribosomes across the tree of life.
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Affiliation(s)
- Paola Londei
- Department of Molecular Medicine, University of Rome Sapienza, Rome, Italy
| | - Sébastien Ferreira-Cerca
- Biochemistry III - Regensburg Center for Biochemistry, Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
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46
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Tartakoff AM, Chen L, Raghavachari S, Gitiforooz D, Dhinakaran A, Ni CL, Pasadyn C, Mahabeleshwar GH, Pasadyn V, Woolford JL. The nucleolus as a polarized coaxial cable in which the rDNA axis is surrounded by dynamic subunit-specific phases. Curr Biol 2021; 31:2507-2519.e4. [PMID: 33862007 PMCID: PMC8222187 DOI: 10.1016/j.cub.2021.03.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/18/2021] [Accepted: 03/11/2021] [Indexed: 12/24/2022]
Abstract
In ribosomal DNA (rDNA) repeats, sequences encoding small-subunit (SSU) rRNA precede those encoding large-subunit (LSU) rRNAs. Processing the composite transcript and subunit assembly requires >100 subunit-specific nucleolar assembly factors (AFs). To investigate the functional organization of the nucleolus, we localized AFs in S. cerevisiae in which the rDNA axis was "linearized" to reduce its dimensionality, thereby revealing its coaxial organization. In this situation, rRNA synthesis and processing continue. The axis is embedded in an inner layer/phase of SSU AFs that is surrounded by an outer layer/phase of LSU AFs. When subunit production is inhibited, subsets of AFs differentially relocate between the inner and outer layers, as expected if there is a cycle of repeated relocation whereby "latent" AFs become "operative" when recruited to nascent subunits. Recognition of AF cycling and localization of segments of rRNA make it possible to infer the existence of assembly intermediates that span between the inner and outer layers and to chart the cotranscriptional assembly of each subunit. AF cycling also can explain how having more than one protein phase in the nucleolus makes possible "vectorial 2-phase partitioning" as a driving force for relocation of nascent rRNPs. Because nucleoplasmic AFs are also present in the outer layer, we propose that critical surface remodeling occurs at this site, thereby partitioning subunit precursors into the nucleoplasm for post-transcriptional maturation. Comparison to observations on higher eukaryotes shows that the coaxial paradigm is likely to be applicable for the many other organisms that have rDNA repeats.
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Affiliation(s)
- Alan M Tartakoff
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA.
| | - Lan Chen
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Shashank Raghavachari
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Daria Gitiforooz
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Akshyasri Dhinakaran
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Chun-Lun Ni
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | | | - Ganapati H Mahabeleshwar
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Vanessa Pasadyn
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - John L Woolford
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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47
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Knüppel R, Trahan C, Kern M, Wagner A, Grünberger F, Hausner W, Quax TEF, Albers SV, Oeffinger M, Ferreira-Cerca S. Insights into synthesis and function of KsgA/Dim1-dependent rRNA modifications in archaea. Nucleic Acids Res 2021; 49:1662-1687. [PMID: 33434266 PMCID: PMC7897474 DOI: 10.1093/nar/gkaa1268] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/01/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022] Open
Abstract
Ribosomes are intricate molecular machines ensuring proper protein synthesis in every cell. Ribosome biogenesis is a complex process which has been intensively analyzed in bacteria and eukaryotes. In contrast, our understanding of the in vivo archaeal ribosome biogenesis pathway remains less characterized. Here, we have analyzed the in vivo role of the almost universally conserved ribosomal RNA dimethyltransferase KsgA/Dim1 homolog in archaea. Our study reveals that KsgA/Dim1-dependent 16S rRNA dimethylation is dispensable for the cellular growth of phylogenetically distant archaea. However, proteomics and functional analyses suggest that archaeal KsgA/Dim1 and its rRNA modification activity (i) influence the expression of a subset of proteins and (ii) contribute to archaeal cellular fitness and adaptation. In addition, our study reveals an unexpected KsgA/Dim1-dependent variability of rRNA modifications within the archaeal phylum. Combining structure-based functional studies across evolutionary divergent organisms, we provide evidence on how rRNA structure sequence variability (re-)shapes the KsgA/Dim1-dependent rRNA modification status. Finally, our results suggest an uncoupling between the KsgA/Dim1-dependent rRNA modification completion and its release from the nascent small ribosomal subunit. Collectively, our study provides additional understandings into principles of molecular functional adaptation, and further evolutionary and mechanistic insights into an almost universally conserved step of ribosome synthesis.
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Affiliation(s)
- Robert Knüppel
- Regensburg Center for Biochemistry, Biochemistry III – Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Christian Trahan
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec H3A 1A3, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Michael Kern
- Regensburg Center for Biochemistry, Biochemistry III – Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Alexander Wagner
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, Microbiology, University of Freiburg, Freiburg, Germany
| | - Felix Grünberger
- Chair of Microbiology – Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Winfried Hausner
- Chair of Microbiology – Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Tessa E F Quax
- Archaeal Virus-Host Interactions, Institute of Biology II, Faculty of Biology, Microbiology, University of Freiburg, Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, Microbiology, University of Freiburg, Freiburg, Germany
| | - Marlene Oeffinger
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec H3A 1A3, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Sébastien Ferreira-Cerca
- Regensburg Center for Biochemistry, Biochemistry III – Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
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48
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Mechanisms and regulation of protein synthesis in mitochondria. Nat Rev Mol Cell Biol 2021; 22:307-325. [PMID: 33594280 DOI: 10.1038/s41580-021-00332-2] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
Mitochondria are cellular organelles responsible for generation of chemical energy in the process called oxidative phosphorylation. They originate from a bacterial ancestor and maintain their own genome, which is expressed by designated, mitochondrial transcription and translation machineries that differ from those operating for nuclear gene expression. In particular, the mitochondrial protein synthesis machinery is structurally and functionally very different from that governing eukaryotic, cytosolic translation. Despite harbouring their own genetic information, mitochondria are far from being independent of the rest of the cell and, conversely, cellular fitness is closely linked to mitochondrial function. Mitochondria depend heavily on the import of nuclear-encoded proteins for gene expression and function, and hence engage in extensive inter-compartmental crosstalk to regulate their proteome. This connectivity allows mitochondria to adapt to changes in cellular conditions and also mediates responses to stress and mitochondrial dysfunction. With a focus on mammals and yeast, we review fundamental insights that have been made into the biogenesis, architecture and mechanisms of the mitochondrial translation apparatus in the past years owing to the emergence of numerous near-atomic structures and a considerable amount of biochemical work. Moreover, we discuss how cellular mitochondrial protein expression is regulated, including aspects of mRNA and tRNA maturation and stability, roles of auxiliary factors, such as translation regulators, that adapt mitochondrial translation rates, and the importance of inter-compartmental crosstalk with nuclear gene expression and cytosolic translation and how it enables integration of mitochondrial translation into the cellular context.
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49
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Tobiasson V, Gahura O, Aibara S, Baradaran R, Zíková A, Amunts A. Interconnected assembly factors regulate the biogenesis of mitoribosomal large subunit. EMBO J 2021; 40:e106292. [PMID: 33576519 PMCID: PMC7957421 DOI: 10.15252/embj.2020106292] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/18/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mitoribosomes consist of ribosomal RNA and protein components, coordinated assembly of which is critical for function. We used mitoribosomes from Trypanosoma brucei with reduced RNA and increased protein mass to provide insights into the biogenesis of the mitoribosomal large subunit. Structural characterization of a stable assembly intermediate revealed 22 assembly factors, some of which have orthologues/counterparts/homologues in mammalian genomes. These assembly factors form a protein network that spans a distance of 180 Å, shielding the ribosomal RNA surface. The central protuberance and L7/L12 stalk are not assembled entirely and require removal of assembly factors and remodeling of the mitoribosomal proteins to become functional. The conserved proteins GTPBP7 and mt‐EngA are bound together at the subunit interface in proximity to the peptidyl transferase center. A mitochondrial acyl‐carrier protein plays a role in docking the L1 stalk, which needs to be repositioned during maturation. Additional enzymatically deactivated factors scaffold the assembly while the exit tunnel is blocked. Together, this extensive network of accessory factors stabilizes the immature sites and connects the functionally important regions of the mitoribosomal large subunit.
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Affiliation(s)
- Victor Tobiasson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Shintaro Aibara
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Rozbeh Baradaran
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
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50
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Hör J, Di Giorgio S, Gerovac M, Venturini E, Förstner KU, Vogel J. Grad-seq shines light on unrecognized RNA and protein complexes in the model bacterium Escherichia coli. Nucleic Acids Res 2020; 48:9301-9319. [PMID: 32813020 PMCID: PMC7498339 DOI: 10.1093/nar/gkaa676] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/29/2020] [Accepted: 08/14/2020] [Indexed: 12/21/2022] Open
Abstract
Stable protein complexes, including those formed with RNA, are major building blocks of every living cell. Escherichia coli has been the leading bacterial organism with respect to global protein-protein networks. Yet, there has been no global census of RNA/protein complexes in this model species of microbiology. Here, we performed Grad-seq to establish an RNA/protein complexome, reconstructing sedimentation profiles in a glycerol gradient for ∼85% of all E. coli transcripts and ∼49% of the proteins. These include the majority of small noncoding RNAs (sRNAs) detectable in this bacterium as well as the general sRNA-binding proteins, CsrA, Hfq and ProQ. In presenting use cases for utilization of these RNA and protein maps, we show that a stable association of RyeG with 30S ribosomes gives this seemingly noncoding RNA of prophage origin away as an mRNA of a toxic small protein. Similarly, we show that the broadly conserved uncharacterized protein YggL is a 50S subunit factor in assembled 70S ribosomes. Overall, this study crucially extends our knowledge about the cellular interactome of the primary model bacterium E. coli through providing global RNA/protein complexome information and should facilitate functional discovery in this and related species.
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Affiliation(s)
- Jens Hör
- Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
| | - Silvia Di Giorgio
- Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany.,ZB MED - Information Centre for Life Sciences, D-50931 Cologne, Germany
| | - Milan Gerovac
- Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
| | - Elisa Venturini
- Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
| | - Konrad U Förstner
- ZB MED - Information Centre for Life Sciences, D-50931 Cologne, Germany.,TH Köln, Faculty of Information Science and Communication Studies, D-50678 Cologne, Germany
| | - Jörg Vogel
- Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany.,Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080 Würzburg, Germany
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