1
|
Moreira S, Chyou TY, Wade J, Brown C. Diversification of the Rho transcription termination factor in bacteria. Nucleic Acids Res 2024; 52:8979-8997. [PMID: 38966992 PMCID: PMC11347177 DOI: 10.1093/nar/gkae582] [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: 10/26/2023] [Revised: 06/17/2024] [Accepted: 06/24/2024] [Indexed: 07/06/2024] Open
Abstract
Correct termination of transcription is essential for gene expression. In bacteria, factor-dependent termination relies on the Rho factor, that classically has three conserved domains. Some bacteria also have a functional insertion region. However, the variation in Rho structure among bacteria has not been analyzed in detail. This study determines the distribution, sequence conservation, and predicted features of Rho factors with diverse domain architectures by analyzing 2730 bacterial genomes. About half (49.8%) of the species analyzed have the typical Escherichia coli like Rho while most of the other species (39.8%) have diverse, atypical forms of Rho. Besides conservation of the main domains, we describe a duplicated RNA-binding domain present in specific species and novel variations in the bicyclomycin binding pocket. The additional regions observed in Rho proteins exhibit remarkable diversity. Commonly, however, they have exceptional amino acid compositions and are predicted to be intrinsically disordered, to undergo phase separation, or have prion-like behavior. Phase separation has recently been shown to play roles in Rho function and bacterial fitness during harsh conditions in one species and this study suggests a more widespread role. In conclusion, diverse atypical Rho factors are broadly distributed among bacteria, suggesting additional cellular roles.
Collapse
Affiliation(s)
- Sofia M Moreira
- Department of Biochemistry, University of Otago, Dunedin, Otago 9054, New Zealand
| | - Te-yuan Chyou
- Department of Biochemistry, University of Otago, Dunedin, Otago 9054, New Zealand
| | - Joseph T Wade
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY 12222, USA
| | - Chris M Brown
- Department of Biochemistry, University of Otago, Dunedin, Otago 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, Otago 9054, New Zealand
| |
Collapse
|
2
|
Zhang J. Recognition of the tRNA structure: Everything everywhere but not all at once. Cell Chem Biol 2024; 31:36-52. [PMID: 38159570 PMCID: PMC10843564 DOI: 10.1016/j.chembiol.2023.12.008] [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: 08/27/2023] [Revised: 12/02/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
tRNAs are among the most abundant and essential biomolecules in cells. These spontaneously folding, extensively structured yet conformationally flexible anionic polymers literally bridge the worlds of RNAs and proteins, and serve as Rosetta stones that decipher and interpret the genetic code. Their ubiquitous presence, functional irreplaceability, and privileged access to cellular compartments and ribosomes render them prime targets for both endogenous regulation and exogenous manipulation. There is essentially no part of the tRNA that is not touched by another interaction partner, either as programmed or imposed by an external adversary. Recent progresses in genetic, biochemical, and structural analyses of the tRNA interactome produced a wealth of new knowledge into their interaction networks, regulatory functions, and molecular interfaces. In this review, I describe and illustrate the general principles of tRNA recognition by proteins and other RNAs, and discuss the underlying molecular mechanisms that deliver affinity, specificity, and functional competency.
Collapse
Affiliation(s)
- Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
| |
Collapse
|
3
|
Beura PK, Sen P, Aziz R, Satapathy SS, Ray SK. Transcribed intergenic regions exhibit a lower frequency of nucleotide polymorphism than the untranscribed intergenic regions in the genomes of Escherichia coli and Salmonella enterica. J Genet 2023. [DOI: 10.1007/s12041-023-01418-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
|
4
|
Murayama Y, Ehara H, Aoki M, Goto M, Yokoyama T, Sekine SI. Structural basis of the transcription termination factor Rho engagement with transcribing RNA polymerase from Thermus thermophilus. SCIENCE ADVANCES 2023; 9:eade7093. [PMID: 36753546 PMCID: PMC9908020 DOI: 10.1126/sciadv.ade7093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Transcription termination is an essential step in transcription by RNA polymerase (RNAP) and crucial for gene regulation. For many bacterial genes, transcription termination is mediated by the adenosine triphosphate-dependent RNA translocase/helicase Rho, which causes RNA/DNA dissociation from the RNAP elongation complex (EC). However, the structural basis of the interplay between Rho and RNAP remains obscure. Here, we report the cryo-electron microscopy structure of the Thermus thermophilus RNAP EC engaged with Rho. The Rho hexamer binds RNAP through the carboxyl-terminal domains, which surround the RNA exit site of RNAP, directing the nascent RNA seamlessly from the RNA exit to its central channel. The β-flap tip at the RNA exit is critical for the Rho-dependent RNA release, and its deletion causes an alternative Rho-RNAP binding mode, which is irrelevant to termination. The Rho binding site overlaps with the binding sites of other macromolecules, such as ribosomes, providing a general basis of gene regulation.
Collapse
Affiliation(s)
- Yuko Murayama
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mari Aoki
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mie Goto
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takeshi Yokoyama
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shun-ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| |
Collapse
|
5
|
Structural basis of Rho-dependent transcription termination. Nature 2023; 614:367-374. [PMID: 36697824 PMCID: PMC9911385 DOI: 10.1038/s41586-022-05658-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/14/2022] [Indexed: 01/26/2023]
Abstract
Rho is a ring-shaped hexameric ATP-dependent molecular motor. Together with the transcription elongation factor NusG, Rho mediates factor-dependent transcription termination and transcription-translation-coupling quality control in Escherichia coli1-4. Here we report the preparation of complexes that are functional in factor-dependent transcription termination from Rho, NusG, RNA polymerase (RNAP), and synthetic nucleic acid scaffolds, and we report cryogenic electron microscopy structures of the complexes. The structures show that functional factor-dependent pre-termination complexes contain a closed-ring Rho hexamer; have RNA threaded through the central channel of Rho; have 60 nucleotides of RNA interacting sequence-specifically with the exterior of Rho and 6 nucleotides of RNA interacting sequence-specifically with the central channel of Rho; have Rho oriented relative to RNAP such that ATP-dependent translocation by Rho exerts mechanical force on RNAP; and have NusG bridging Rho and RNAP. The results explain five decades of research on Rho and provide a foundation for understanding Rho's function.
Collapse
|
6
|
Portela R, A. Faria N, Mwangi M, Miragaia M, de Lencastre H, Tomasz A, Gonçalves Sobral R. Analysis of a Cell Wall Mutant Highlights Rho-Dependent Genome Amplification Events in Staphylococcus aureus. Microbiol Spectr 2022; 10:e0248321. [PMID: 36094182 PMCID: PMC9603463 DOI: 10.1128/spectrum.02483-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 08/06/2022] [Indexed: 01/04/2023] Open
Abstract
In a study of antibiotic resistance in Staphylococcus aureus, specific cell wall mutants were previously generated for the peptidoglycan biosynthesis gene murF, by the insertion of an integrative plasmid. A collection of 30 independent mutants was obtained, and all harbored a variable number of copies of the inserted plasmid, arranged in tandem in the chromosome. Of the 30 mutants, only 3, F9, F20 and F26, with a lower number of plasmid copies, showed an altered peptidoglycan structure, lower resistance to β-lactams and a different loss-of-function mutation in rho gene, that encodes a transcription termination factor. The rho mutations were found to correlate with the level of oxacillin resistance, since genetic complementation with rho gene reestablished the resistance and cell wall parental profile in F9, F20 and F26 strains. Furthermore, complementation with rho resulted in the amplification of the number of plasmid tandem repeats, suggesting that Rho enabled events of recombination that favored a rearrangement in the chromosome in the region of the impaired murF gene. Although the full mechanism of reversion of the cell wall damage was not fully elucidated, we showed that Rho is involved in the recombination process that mediates the tandem amplification of exogeneous DNA fragments inserted into the chromosome. IMPORTANCE The cell wall of bacteria, namely, peptidoglycan, is the target of several antibiotic classes such as β-lactams. Staphylococcus aureus is well known for its capacity to adapt to antibiotic stress and develop resistance strategies, namely, to β-lactams. In this context, the construction of cell wall mutants provides useful models to study the development of such resistance mechanisms. Here, we characterized a collection of independent mutants, impaired in the same peptidoglycan biosynthetic step, obtained through the insertion of a plasmid in the coding region of murF gene. S. aureus demonstrated the capacity to overcome the cell wall damage by amplifying the copy number of the inserted plasmid, through an undescribed mechanism that involves the Rho transcription termination factor.
Collapse
Affiliation(s)
- Raquel Portela
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- Laboratory of Molecular Microbiology of Bacterial Pathogens, UCIBIO – Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Nuno A. Faria
- Laboratory of Bacterial Evolution and Molecular Epidemiology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Michael Mwangi
- Laboratory of Microbiology and Infectious Diseases, The Rockefeller University, New York, New York, USA
| | - Maria Miragaia
- Laboratory of Bacterial Evolution and Molecular Epidemiology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Hermínia de Lencastre
- Laboratory of Microbiology and Infectious Diseases, The Rockefeller University, New York, New York, USA
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Alexander Tomasz
- Laboratory of Microbiology and Infectious Diseases, The Rockefeller University, New York, New York, USA
| | - Rita Gonçalves Sobral
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- Laboratory of Molecular Microbiology of Bacterial Pathogens, UCIBIO – Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| |
Collapse
|
7
|
In vivo regulation of bacterial Rho-dependent transcription termination by the nascent RNA. J Biol Chem 2022; 298:102001. [PMID: 35500654 PMCID: PMC9160355 DOI: 10.1016/j.jbc.2022.102001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/23/2022] [Accepted: 04/25/2022] [Indexed: 11/22/2022] Open
Abstract
Bacterial Rho is a RNA-dependent ATPase that functions in the termination of DNA transcription. However, the in vivo nature of the bacterial Rho-dependent terminators, as well as the mechanism of the Rho-dependent termination process, are not fully understood. Here, we measured the in vivo termination efficiencies of 72 Rho-dependent terminators in E. coli by systematically performing qRT-PCR analyses of cDNA prepared from mid-log phase bacterial cultures. We found that these terminators exhibited a wide range of efficiencies, and many behaved differently in vivo compared to the predicted or experimentally determined efficiencies in vitro. Rho-utilization sites (rut sites) present in the RNA terminator sequences are characterized by the presence of C-rich/G-poor sequences, or C>G bubbles. We found that weaker terminators exhibited a robust correlation with the properties (size, length, density, etc.) of these C>G bubbles of their respective rut sites, while stronger terminators lack this correlation, suggesting a limited role of rut sequences in controlling in vivo termination efficiencies. We also found that in vivo termination efficiencies are dependent on the rates of ATP hydrolysis as well as Rho-translocation on the nascent RNA. We demonstrate that weaker terminators, in addition to having rut sites with diminished C>G bubble sizes, are dependent on the Rho-auxiliary factor, NusG, in vivo. From these results, we concluded that in vivo Rho-dependent termination follows a nascent RNA-dependent pathway, where Rho-translocation along the RNA is essential and rut sequences may recruit Rho in vivo, but Rho-rut binding strengths do not regulate termination efficiencies.
Collapse
|
8
|
Cryo-EM structure of transcription termination factor Rho from Mycobacterium tuberculosis reveals bicyclomycin resistance mechanism. Commun Biol 2022; 5:120. [PMID: 35140348 PMCID: PMC8828861 DOI: 10.1038/s42003-022-03069-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/21/2022] [Indexed: 01/17/2023] Open
Abstract
The bacterial Rho factor is a ring-shaped motor triggering genome-wide transcription termination and R-loop dissociation. Rho is essential in many species, including in Mycobacterium tuberculosis where rho gene inactivation leads to rapid death. Yet, the M. tuberculosis Rho [MtbRho] factor displays poor NTPase and helicase activities, and resistance to the natural Rho inhibitor bicyclomycin [BCM] that remain unexplained. To address these issues, we solved the cryo-EM structure of MtbRho at 3.3 Å resolution. The MtbRho hexamer is poised into a pre-catalytic, open-ring state wherein specific contacts stabilize ATP in intersubunit ATPase pockets, thereby explaining the cofactor preference of MtbRho. We reveal a leucine-to-methionine substitution that creates a steric bulk in BCM binding cavities near the positions of ATP γ-phosphates, and confers resistance to BCM at the expense of motor efficiency. Our work contributes to explain the unusual features of MtbRho and provides a framework for future antibiotic development. Cryo-EM shows that M. tuberculosis Rho-factor adopts an open, ring-shaped hexamer conformation and a steric bulk in the cavity for bicyclomycin binding, which explains resistance to the antibiotic.
Collapse
|
9
|
Abstract
Rho is a hexameric bacterial RNA helicase, which became a paradigm of factor-dependent transcription termination. The broadly accepted ("textbook") model posits a series of steps, wherein Rho first binds C-rich Rho utilization (rut) sites on nascent RNA, uses its ATP-dependent translocase activity to catch up with RNA polymerase (RNAP), and either pulls the transcript from the elongation complex or pushes RNAP forward, thus terminating transcription. However, this appealingly simple mechano-chemical model lacks a biological realism and is increasingly at odds with genetic and biochemical data. Here, we summarize recent structural and biochemical studies that have advanced our understanding of molecular details of RNA recognition, termination signaling, and RNAP inactivation in Rho-dependent transcription termination, rebalancing the view in favor of an alternative "allosteric" mechanism. In the revised model, Rho binds RNAP early in elongation assisted by the cofactors NusA and NusG, forming a pre-termination complex (PTC). The formation of PTC allows Rho to continuously sample nascent transcripts for a termination signal, which subsequently traps the elongation complex in an inactive state prior to its dissociation.
Collapse
Affiliation(s)
- Zhitai Hao
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Vladimir Svetlov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.,Howard Hughes Medical Institute, New York University School of Medicine, New York, Ny, USA
| |
Collapse
|
10
|
Nikulin AD. Characteristic Features of Protein Interaction with Single- and Double-Stranded RNA. BIOCHEMISTRY (MOSCOW) 2021; 86:1025-1040. [PMID: 34488578 DOI: 10.1134/s0006297921080125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The review discusses differences between the specific protein interactions with single- and double-stranded RNA molecules using the data on the structure of RNA-protein complexes. Proteins interacting with the single-stranded RNAs form contacts with RNA bases, which ensures recognition of specific nucleotide sequences. Formation of such contacts with the double-stranded RNAs is hindered, so that the proteins recognize unique conformations of the RNA spatial structure and interact mainly with the RNA sugar-phosphate backbone.
Collapse
Affiliation(s)
- Alexey D Nikulin
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| |
Collapse
|
11
|
Fucci IJ, Sinha K, Rule GS. Protein Dynamics Is Altered by a High Surface Density of Atomic Transfer Radical Polymerization Polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7185-7193. [PMID: 34048258 DOI: 10.1021/acs.langmuir.1c00755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The effect of atomic transfer radical polymerization (ATRP) polymers on the structure and dynamics of a 14.5 kDa RNA binding protein, Rho130, was assessed using NMR. A near-homogeneous sample was generated by optimizing initiator coupling to maximize the number of modified Lys residues. The reactivity of individual Lys residues was correlated with the average solvent accessible surface area from molecular dynamics (MD) simulations and influenced by local interactions. Larger structural changes were seen with the addition of the initiator alone than with polymer growth. Structural changes were localized to the N-terminal helical domain of the protein and MD simulations suggest stabilization of the terminus of one helix by the addition of the ATRP initiator and an initiator-induced change in interhelical angles. Relaxation dispersion shows that polymer addition, but not attachment of the initiator, causes a reduction in the microsecond-millisecond dynamics of the hydrophobic core.
Collapse
Affiliation(s)
- Ian J Fucci
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Kaustubh Sinha
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Gordon S Rule
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
12
|
Simon I, Delaleau M, Schwartz A, Boudvillain M. A Large Insertion Domain in the Rho Factor From a Low G + C, Gram-negative Bacterium is Critical for RNA Binding and Transcription Termination Activity. J Mol Biol 2021; 433:167060. [PMID: 34023400 DOI: 10.1016/j.jmb.2021.167060] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/30/2021] [Accepted: 05/16/2021] [Indexed: 10/21/2022]
Abstract
Rho-dependent termination of transcription (RDTT) is a critical regulatory mechanism specific to bacteria. In a subset of species including most Actinobacteria and Bacteroidetes, the Rho factor contains a large, poorly conserved N-terminal insertion domain (NID) of cryptic function. To date, only two NID-bearing Rho factors from high G + C Actinobacteria have been thoroughly characterized. Both can trigger RDTT at promoter-proximal sites or with structurally constrained transcripts that are unsuitable for the archetypal, NID-less Rho factor of Escherichia coli (EcRho). Here, we provide the first biochemical characterization of a NID-bearing Rho factor from a low G + C bacterium. We show that Bacteroides fragilis Rho (BfRho) is a bona fide RNA-dependent NTPase motor able to unwind long RNA:DNA duplexes and to disrupt transcription complexes. The large NID (~40% of total mass) strongly increases BfRho affinity for RNA, is strictly required for RDTT, but does not promote RDTT at promoter-proximal sites or with a structurally constrained transcript. Furthermore, the NID does not preclude modulation of RDTT by transcription factors NusA and NusG or by the Rho inhibitor bicyclomycin. Although the NID contains a prion-like Q/N-rich motif, it does not spontaneously trigger formation of β-amyloids. Thus, despite its unusually large RNA binding domain, BfRho behaves more like the NID-less EcRho than NID-bearing counterparts from high G + C Actinobacteria. Our data highlight the evolutionary plasticity of Rho's N-terminal region and illustrate how RDTT is adapted to distinct genomic contents.
Collapse
Affiliation(s)
- Isabelle Simon
- Centre de Biophysique Moléculaire, CNRS UPR4301, Rue Charles Sadron, 45071 Orléans cedex 2, France; ED 549, Santé, Sciences Biologiques & Chimie du Vivant, Université d'Orléans, France
| | - Mildred Delaleau
- Centre de Biophysique Moléculaire, CNRS UPR4301, Rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Annie Schwartz
- Centre de Biophysique Moléculaire, CNRS UPR4301, Rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, Rue Charles Sadron, 45071 Orléans cedex 2, France.
| |
Collapse
|
13
|
Bythell-Douglas R, Deans AJ. A Structural Guide to the Bloom Syndrome Complex. Structure 2020; 29:99-113. [PMID: 33357470 DOI: 10.1016/j.str.2020.11.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/03/2020] [Accepted: 11/25/2020] [Indexed: 01/19/2023]
Abstract
The Bloom syndrome complex is a DNA damage repair machine. It consists of several protein components which are functional in isolation, but interdependent in cells for the maintenance of accurate homologous recombination. Mutations to any of the genes encoding these proteins cause numerous physical and developmental markers as well as phenotypes of genome instability, infertility, and cancer predisposition. Here we review the published structural and biochemical data on each of the components of the complex: the helicase BLM, the type IA topoisomerase TOP3A, and the OB-fold-containing RMI and RPA subunits. We describe how each component contributes to function, interacts with each other, and the DNA that it manipulates/repairs.
Collapse
Affiliation(s)
- Rohan Bythell-Douglas
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC, 3056, Australia.
| | - Andrew J Deans
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC, 3056, Australia; Department of Medicine (St Vincent's), University of Melbourne, Fitzroy, VIC, 3056, Australia.
| |
Collapse
|
14
|
Bossi L, Figueroa-Bossi N, Bouloc P, Boudvillain M. Regulatory interplay between small RNAs and transcription termination factor Rho. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194546. [PMID: 32217107 DOI: 10.1016/j.bbagrm.2020.194546] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/12/2020] [Accepted: 03/20/2020] [Indexed: 12/14/2022]
Abstract
The largest and best studied group of regulatory small RNAs (sRNAs) in bacteria act by modulating translation or turnover of messenger RNAs (mRNAs) through base-pairing interactions that typically take place near the 5' end of the mRNA. This allows the sRNA to bind the complementary target sequence while the remainder of the mRNA is still being made, creating conditions whereby the action of the sRNA can extend to transcriptional steps, most notably transcription termination. Increasing evidence corroborates the existence of a functional interplay between sRNAs and termination factor Rho. Two general mechanisms have emerged. One mechanism operates in translated regions subjected to sRNA repression. By inhibiting ribosome binding co-transcriptionally, the sRNA uncouples translation from transcription, allowing Rho to bind the nascent RNA and promote termination. In the second mechanism, which functions in 5' untranslated regions, the sRNA antagonizes termination directly by interfering with Rho binding to the RNA or the subsequent translocation along the RNA. Here, we review the above literature in the context of other mechanisms that underlie the participation of Rho-dependent transcription termination in gene regulation. This article is part of a Special Issue entitled: RNA and gene control in bacteria edited by Dr. M. Guillier and F. Repoila.
Collapse
Affiliation(s)
- Lionello Bossi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Nara Figueroa-Bossi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Philippe Bouloc
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France
| |
Collapse
|
15
|
Nadiras C, Eveno E, Schwartz A, Figueroa-Bossi N, Boudvillain M. A multivariate prediction model for Rho-dependent termination of transcription. Nucleic Acids Res 2019; 46:8245-8260. [PMID: 29931073 PMCID: PMC6144790 DOI: 10.1093/nar/gky563] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/08/2018] [Indexed: 11/13/2022] Open
Abstract
Bacterial transcription termination proceeds via two main mechanisms triggered either by simple, well-conserved (intrinsic) nucleic acid motifs or by the motor protein Rho. Although bacterial genomes can harbor hundreds of termination signals of either type, only intrinsic terminators are reliably predicted. Computational tools to detect the more complex and diversiform Rho-dependent terminators are lacking. To tackle this issue, we devised a prediction method based on Orthogonal Projections to Latent Structures Discriminant Analysis [OPLS-DA] of a large set of in vitro termination data. Using previously uncharacterized genomic sequences for biochemical evaluation and OPLS-DA, we identified new Rho-dependent signals and quantitative sequence descriptors with significant predictive value. Most relevant descriptors specify features of transcript C>G skewness, secondary structure, and richness in regularly-spaced 5'CC/UC dinucleotides that are consistent with known principles for Rho-RNA interaction. Descriptors collectively warrant OPLS-DA predictions of Rho-dependent termination with a ∼85% success rate. Scanning of the Escherichia coli genome with the OPLS-DA model identifies significantly more termination-competent regions than anticipated from transcriptomics and predicts that regions intrinsically refractory to Rho are primarily located in open reading frames. Altogether, this work delineates features important for Rho activity and describes the first method able to predict Rho-dependent terminators in bacterial genomes.
Collapse
Affiliation(s)
- Cédric Nadiras
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France.,ED 549, Sciences Biologiques & Chimie du Vivant, Université d'Orléans, France
| | - Eric Eveno
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Annie Schwartz
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Nara Figueroa-Bossi
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University of Paris-Sud, University of Paris-Saclay, Gif-sur-Yvette, France
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France
| |
Collapse
|
16
|
Tuning the sequence specificity of a transcription terminator. Curr Genet 2019; 65:729-733. [PMID: 30739200 DOI: 10.1007/s00294-019-00939-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/17/2019] [Indexed: 01/08/2023]
Abstract
The bacterial hexameric helicase known as Rho is an archetypal sequence-specific transcription terminator that typically halts the synthesis of a defined set of transcripts, particularly those bearing cytosine-rich 3'-untranslated regions. However, under conditions of translational stress, Rho can also terminate transcription at cytosine-poor sites when assisted by the transcription factor NusG. Recent structural, biochemical, and computational studies of the Rho·NusG interaction in Escherichia coli have helped establish how NusG reprograms Rho activity. NusG is found to be an allosteric activator of Rho that directly binds to the ATPase motor domain of the helicase and facilitates closure of the Rho ring around non-ideal (purine-rich) target RNAs. The manner in which NusG acts on Rho helps to explain how the transcription terminator is excluded from acting on RNA polymerase by exogenous factors, such as the antitermination protein NusE, the NusG paralog RfaH, and RNA polymerase-coupled ribosomes. Collectively, an understanding of the link between NusG and Rho provides new insights into how transcriptional and translational fidelity are maintained during gene expression in bacteria.
Collapse
|
17
|
Lawson MR, Ma W, Bellecourt MJ, Artsimovitch I, Martin A, Landick R, Schulten K, Berger JM. Mechanism for the Regulated Control of Bacterial Transcription Termination by a Universal Adaptor Protein. Mol Cell 2018; 71:911-922.e4. [PMID: 30122535 DOI: 10.1016/j.molcel.2018.07.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/21/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022]
Abstract
NusG/Spt5 proteins are the only transcription factors utilized by all cellular organisms. In enterobacteria, NusG antagonizes the transcription termination activity of Rho, a hexameric helicase, during the synthesis of ribosomal and actively translated mRNAs. Paradoxically, NusG helps Rho act on untranslated transcripts, including non-canonical antisense RNAs and those arising from translational stress; how NusG fulfills these disparate functions is unknown. Here, we demonstrate that NusG activates Rho by assisting helicase isomerization from an open-ring, RNA-loading state to a closed-ring, catalytically active translocase. A crystal structure of closed-ring Rho in complex with NusG reveals the physical basis for this activation and further explains how Rho is excluded from translationally competent RNAs. This study demonstrates how a universally conserved transcription factor acts to modulate the activity of a ring-shaped ATPase motor and establishes how the innate sequence bias of a termination factor can be modulated to silence pervasive, aberrant transcription.
Collapse
Affiliation(s)
- Michael R Lawson
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Wen Ma
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science Technology, Urbana, IL 61801, USA; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Michael J Bellecourt
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Klaus Schulten
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science Technology, Urbana, IL 61801, USA; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - James M Berger
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
18
|
Abstract
At the end of the multistep transcription process, the elongating RNA polymerase (RNAP) is dislodged from the DNA template either at specific DNA sequences, called the terminators, or by a nascent RNA-dependent helicase, Rho. In Escherichia coli, about half of the transcription events are terminated by the Rho protein. Rho utilizes its RNA-dependent ATPase activities to translocate along the mRNA and eventually dislodges the RNAP via an unknown mechanism. The transcription elongation factor NusG facilitates this termination process by directly interacting with Rho. In this review, we discuss current models describing the mechanism of action of this hexameric transcription terminator, its regulation by different cis and trans factors, and the effects of the termination process on physiological processes in bacterial cells, particularly E. coli and Salmonella enterica Typhimurium.
Collapse
Affiliation(s)
- Pallabi Mitra
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad-500001, India; , , ,
| | - Gairika Ghosh
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad-500001, India; , , , .,Department of Graduate Studies, Manipal University, Manipal, Karnataka-576104, India
| | - Md Hafeezunnisa
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad-500001, India; , , , .,Department of Graduate Studies, Manipal University, Manipal, Karnataka-576104, India
| | - Ranjan Sen
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad-500001, India; , , ,
| |
Collapse
|
19
|
Transcriptional pausing at the translation start site operates as a critical checkpoint for riboswitch regulation. Nat Commun 2017; 8:13892. [PMID: 28071751 PMCID: PMC5234074 DOI: 10.1038/ncomms13892] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/10/2016] [Indexed: 11/24/2022] Open
Abstract
On the basis of nascent transcript sequencing, it has been postulated but never demonstrated that transcriptional pausing at translation start sites is important for gene regulation. Here we show that the Escherichia coli thiamin pyrophosphate (TPP) thiC riboswitch contains a regulatory pause site in the translation initiation region that acts as a checkpoint for thiC expression. By biochemically probing nascent transcription complexes halted at defined positions, we find a narrow transcriptional window for metabolite binding, in which the downstream boundary is delimited by the checkpoint. We show that transcription complexes at the regulatory pause site favour the formation of a riboswitch intramolecular lock that strongly prevents TPP binding. In contrast, cotranscriptional metabolite binding increases RNA polymerase pausing and induces Rho-dependent transcription termination at the checkpoint. Early transcriptional pausing may provide a general mechanism, whereby transient transcriptional windows directly coordinate the sensing of environmental cues and bacterial mRNA regulation. Riboswitches are non-coding RNA elements that detect metabolites and control expression by regulating mRNA levels or translation. Here, the authors provide evidence that the E. coli thiC riboswitch has a pause site in the translation initiation region that acts as a checkpoint for thiC expression.
Collapse
|
20
|
Ligand-induced and small-molecule control of substrate loading in a hexameric helicase. Proc Natl Acad Sci U S A 2016; 113:13714-13719. [PMID: 27821776 DOI: 10.1073/pnas.1616749113] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Processive, ring-shaped protein and nucleic acid protein translocases control essential biochemical processes throughout biology and are considered high-prospect therapeutic targets. The Escherichia coli Rho factor is an exemplar hexameric RNA translocase that terminates transcription in bacteria. As with many ring-shaped motor proteins, Rho activity is modulated by a variety of poorly understood mechanisms, including small-molecule therapeutics, protein-protein interactions, and the sequence of its translocation substrate. Here, we establish the mechanism of action of two Rho effectors, the antibiotic bicyclomycin and nucleic acids that bind to Rho's primary RNA recruitment site. Using small-angle X-ray scattering and a fluorescence-based assay to monitor the ability of Rho to switch between open-ring (RNA-loading) and closed-ring (RNA-translocation) states, we found bicyclomycin to be a direct antagonist of ring closure. Reciprocally, the binding of nucleic acids to its N-terminal RNA recruitment domains is shown to promote the formation of a closed-ring Rho state, with increasing primary-site occupancy providing additive stimulatory effects. This study establishes bicyclomycin as a conformational inhibitor of Rho ring dynamics, highlighting the utility of developing assays that read out protein conformation as a prospective screening tool for ring-ATPase inhibitors. Our findings further show that the RNA sequence specificity used for guiding Rho-dependent termination derives in part from an intrinsic ability of the motor to couple the recognition of pyrimidine patterns in nascent transcripts to RNA loading and activity.
Collapse
|
21
|
Learning from the Leaders: Gene Regulation by the Transcription Termination Factor Rho. Trends Biochem Sci 2016; 41:690-699. [PMID: 27325240 DOI: 10.1016/j.tibs.2016.05.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 05/18/2016] [Accepted: 05/25/2016] [Indexed: 01/23/2023]
Abstract
The RNA helicase Rho triggers 20-30% of transcription termination events in bacteria. While Rho is associated with most transcription elongation complexes, it only promotes termination of a subset. Recent studies of individual Rho-dependent terminators located within the 5' leader regions of bacterial mRNAs have identified novel mechanisms that govern Rho target specificity and have revealed unanticipated physiological functions for Rho. In particular, the multistep nature of Rho-dependent termination enables regulatory input from determinants beyond the sequence of the Rho loading site, and allows a given Rho-dependent terminator to respond to multiple signals. Further, the unique position of Rho as a sensor of cellular translation has been exploited to regulate the transcription of genes required for protein synthesis, including those specifying Mg(2+) transporters.
Collapse
|
22
|
Grylak-Mielnicka A, Bidnenko V, Bardowski J, Bidnenko E. Transcription termination factor Rho: a hub linking diverse physiological processes in bacteria. Microbiology (Reading) 2016; 162:433-447. [DOI: 10.1099/mic.0.000244] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Aleksandra Grylak-Mielnicka
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
- Institute of Biochemistry and Biophysics PAS, 02-106 Warsaw, Poland
| | - Vladimir Bidnenko
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Jacek Bardowski
- Institute of Biochemistry and Biophysics PAS, 02-106 Warsaw, Poland
| | - Elena Bidnenko
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| |
Collapse
|
23
|
Pallarès I, Iglesias V, Ventura S. The Rho Termination Factor of Clostridium botulinum Contains a Prion-Like Domain with a Highly Amyloidogenic Core. Front Microbiol 2016; 6:1516. [PMID: 26779170 PMCID: PMC4703818 DOI: 10.3389/fmicb.2015.01516] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 12/16/2015] [Indexed: 11/27/2022] Open
Abstract
Prion-like proteins can switch between a soluble intrinsically disordered conformation and a highly ordered amyloid assembly. This conformational promiscuity is encoded in specific sequence regions, known as prion domains (PrDs). Prions are best known as the causative factors of neurological diseases in mammals. However, bioinformatics analyses reveal that proteins bearing PrDs are present in all kingdoms of life, including bacteria, thus supporting the idea that they serve conserved beneficial cellular functions. Despite the proportion of predicted prion-like proteins in bacterial proteomes is generally low, pathogenic species seem to have a higher prionic load, suggesting that these malleable proteins may favor pathogenic traits. In the present work, we performed a stringent computational analysis of the Clostridium botulinum pathogen proteome in the search for prion-like proteins. A total of 54 candidates were predicted for this anaerobic bacterium, including the transcription termination Rho factor. This RNA-binding protein has been shown to play a crucial role in bacterial adaptation to changing environments. We show here that the predicted disordered PrD domain of this RNA-binding protein contains an inner, highly polar, asparagine-rich short sequence able to spontaneously self-assemble into amyloid-like structures, bearing thus the potential to induce a Rho factor conformational switch that might rewire gene expression in response to environmental conditions.
Collapse
Affiliation(s)
- Irantzu Pallarès
- Institut de Biotecnologia i Biomedicina and Departament de Bioquìmica i Biologia Molecular, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Valentin Iglesias
- Institut de Biotecnologia i Biomedicina and Departament de Bioquìmica i Biologia Molecular, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Salvador Ventura
- Institut de Biotecnologia i Biomedicina and Departament de Bioquìmica i Biologia Molecular, Universitat Autònoma de Barcelona Barcelona, Spain
| |
Collapse
|
24
|
The Bacterial Transcription Termination Factor Rho Coordinates Mg(2+) Homeostasis with Translational Signals. J Mol Biol 2015; 427:3834-49. [PMID: 26523680 DOI: 10.1016/j.jmb.2015.10.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 12/22/2022]
Abstract
The bacterial protein Rho triggers transcription termination at the ends of many operons and when transcription and translation become uncoupled. In addition to these genome wide activities, Rho implements regulation of specific genes by dictating whether RNA polymerase terminates transcription within the 5' leader region or continues into the downstream coding region. Here, we report that the Mg(2+) channel gene corA in Salmonella enterica serovar Typhimurium, which was previously thought to be constitutively expressed, is regulated by a Rho-dependent terminator located within its 5' leader region. We demonstrate that the unusually long and highly conserved corA leader mRNA can adopt two mutually exclusive conformations that determine whether or not Rho interacts with a Rho utilization site on the nascent RNA and thereby prevents transcription of the corA coding region. The RNA conformation that promotes Rho-dependent termination is favored by efficient translation of corL, a short open reading frame located within the corA leader. Thus, corA transcription is inversely coupled to corL translation. This mechanism resembles those governing expression of Salmonella's other two Mg(2+) transport genes, suggesting that Rho links Mg(2+) uptake to translational signals.
Collapse
|
25
|
Gocheva V, Le Gall A, Boudvillain M, Margeat E, Nollmann M. Direct observation of the translocation mechanism of transcription termination factor Rho. Nucleic Acids Res 2015; 43:2367-77. [PMID: 25662222 PMCID: PMC4344519 DOI: 10.1093/nar/gkv085] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Rho is a ring-shaped, ATP-fueled motor essential for remodeling transcriptional complexes and R-loops in bacteria. Despite years of research on this fundamental model helicase, key aspects of its mechanism of translocation remain largely unknown. Here, we used single-molecule manipulation and fluorescence methods to directly monitor the dynamics of RNA translocation by Rho. We show that the efficiency of Rho activation is strongly dependent on the force applied on the RNA but that, once active, Rho is able to translocate against a large opposing force (at least 7 pN) by a mechanism involving ‘tethered tracking’. Importantly, the ability to directly measure dynamics at the single-molecule level allowed us to determine essential motor properties of Rho. Hence, Rho translocates at a rate of ∼56 nt per second under our experimental conditions, which is 2–5 times faster than velocities measured for RNA polymerase under similar conditions. Moreover, the processivity of Rho (∼62 nt at a 7 pN opposing force) is large enough for Rho to reach termination sites without dissociating from its RNA loading site, potentially increasing the efficiency of transcription termination. Our findings unambiguously establish ‘tethered tracking’ as the main pathway for Rho translocation, support ‘kinetic coupling’ between Rho and RNA polymerase during Rho-dependent termination, and suggest that forces applied on the nascent RNA transcript by cellular substructures could have important implications for the regulation of transcription and its coupling to translation in vivo.
Collapse
Affiliation(s)
- Veronika Gocheva
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| | - Antoine Le Gall
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| | - Marc Boudvillain
- CNRS, Centre de Biophysique Moléculaire, rue Charles Sadron, 45071 Orléans, France ITP Sciences Biologiques & Chimie du Vivant, Université d'Orléans, France
| | - Emmanuel Margeat
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| | - Marcelo Nollmann
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| |
Collapse
|
26
|
Mitra A, Misquitta R, Nagaraja V. Mycobacterium tuberculosis Rho is an NTPase with distinct kinetic properties and a novel RNA-binding subdomain. PLoS One 2014; 9:e107474. [PMID: 25229539 PMCID: PMC4167861 DOI: 10.1371/journal.pone.0107474] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/18/2014] [Indexed: 11/29/2022] Open
Abstract
Two mechanisms--factor independent and dependent termination--ensure the completion of RNA synthesis in eubacteria. Factor-dependent mechanism relies on the Rho protein to terminate transcription by interacting with RNA polymerase. Although well studied in Escherichia coli, the properties of the Rho homologs from most bacteria are not known. The rho gene is unusually large in genus Mycobacterium and other members of actinobacteria, having ∼150 additional residues towards the amino terminal end. We describe the distinct properties of Rho from Mycobacterium tuberculosis. It is an NTPase with a preference for purine nucleoside triphosphates with kinetic properties different from E. coli homolog and an ability to use various RNA substrates. The N-terminal subdomain of MtbRho can bind to RNA by itself, and appears to contribute to the interaction of the termination factor with RNAs. Furthermore, the interaction with RNA induces changes in conformation and oligomerization of MtbRho.
Collapse
Affiliation(s)
- Anirban Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Rachel Misquitta
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| |
Collapse
|
27
|
Soares E, Schwartz A, Nollmann M, Margeat E, Boudvillain M. The RNA-mediated, asymmetric ring regulatory mechanism of the transcription termination Rho helicase decrypted by time-resolved nucleotide analog interference probing (trNAIP). Nucleic Acids Res 2014; 42:9270-84. [PMID: 25016524 PMCID: PMC4132721 DOI: 10.1093/nar/gku595] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rho is a ring-shaped, ATP-dependent RNA helicase/translocase that dissociates transcriptional complexes in bacteria. How RNA recognition is coupled to ATP hydrolysis and translocation in Rho is unclear. Here, we develop and use a new combinatorial approach, called time-resolved Nucleotide Analog Interference Probing (trNAIP), to unmask RNA molecular determinants of catalytic Rho function. We identify a regulatory step in the translocation cycle involving recruitment of the 2′-hydroxyl group of the incoming 3′-RNA nucleotide by a Rho subunit. We propose that this step arises from the intrinsic weakness of one of the subunit interfaces caused by asymmetric, split-ring arrangement of primary RNA tethers around the Rho hexamer. Translocation is at highest stake every seventh nucleotide when the weak interface engages the incoming 3′-RNA nucleotide or breaks, depending on RNA threading constraints in the Rho pore. This substrate-governed, ‘test to run’ iterative mechanism offers a new perspective on how a ring-translocase may function or be regulated. It also illustrates the interest and versatility of the new trNAIP methodology to unveil the molecular mechanisms of complex RNA-based systems.
Collapse
Affiliation(s)
- Emilie Soares
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Annie Schwartz
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Marcello Nollmann
- CNRS UMR5048, Universités Montpellier I et II, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U1054, Montpellier, France
| | - Emmanuel Margeat
- CNRS UMR5048, Universités Montpellier I et II, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U1054, Montpellier, France
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France ITP Sciences Biologiques & Chimie du Vivant, Université d'Orléans, France
| |
Collapse
|
28
|
Boudvillain M, Figueroa-Bossi N, Bossi L. Terminator still moving forward: expanding roles for Rho factor. Curr Opin Microbiol 2013; 16:118-24. [DOI: 10.1016/j.mib.2012.12.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 12/28/2012] [Accepted: 12/29/2012] [Indexed: 12/29/2022]
|
29
|
Sivasakthi V, Anbarasu A, Ramaiah S. π–π Interactions in Structural Stability: Role in RNA Binding Proteins. Cell Biochem Biophys 2013; 67:853-63. [DOI: 10.1007/s12013-013-9573-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
30
|
Zhang K, Zheng S, Yang JS, Chen Y, Cheng Z. Comprehensive Profiling of Protein Lysine Acetylation in Escherichia coli. J Proteome Res 2013; 12:844-51. [DOI: 10.1021/pr300912q] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Kai Zhang
- State Key Laboratory
of Medicinal Chemical
Biology and Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Shuzhen Zheng
- State Key Laboratory
of Medicinal Chemical
Biology and Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Jeong Soo Yang
- Ben May
Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637,
United States
| | - Yue Chen
- Ben May
Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637,
United States
| | - Zhongyi Cheng
- Ben May
Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637,
United States
| |
Collapse
|
31
|
Stone MD. Getting a grip on the terminator. J Mol Biol 2012; 423:661-3. [PMID: 22975072 DOI: 10.1016/j.jmb.2012.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Michael D Stone
- Department of Chemistry and Biochemistry and the Center for Molecular Biology of RNA, University of California Santa Cruz, CA 95064, USA.
| |
Collapse
|
32
|
Thomsen ND, Berger JM. Crystallization and X-ray structure determination of an RNA-dependent hexameric helicase. Methods Enzymol 2012; 511:171-90. [PMID: 22713320 PMCID: PMC4323581 DOI: 10.1016/b978-0-12-396546-2.00008-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hexameric helicases couple the energy of ATP hydrolysis to processive movement along nucleic acids and are critical components of cells and many viruses. Molecular motion derives from ATP hydrolysis at up to six distinct catalytic centers, which is coupled to the coordinated action of translocation loops in the center of the hexamer. Due to the structural dynamics and catalytic complexity of hexameric helicases, few have been crystallized with a full complement of bound substrates, and instead tend to form crystals belonging to high-symmetry space groups that obscure the differences among catalytic subunits. We were able to overcome these difficulties and solve an asymmetric structure of the Rho transcription termination factor from Escherichia coli bound to ATP mimics and RNA. Here, we present some considerations used for crystallization of this hexameric helicase, discuss the utility of substrate-centric crystal-screening strategies, and outline a crystal-aging screen that allowed us to overcome the adverse effects of nonmerohedral twinning.
Collapse
Affiliation(s)
- Nathan D. Thomsen
- Department of Molecular and Cell Biology and QB3, University of California, Berkeley, CA 94720
| | - James M. Berger
- Department of Molecular and Cell Biology and QB3, University of California, Berkeley, CA 94720
| |
Collapse
|
33
|
WONG WINGCHEONG, MAURER-STROH SEBASTIAN, EISENHABER FRANK. THE JANUS-FACED E-VALUES OF HMMER2: EXTREME VALUE DISTRIBUTION OR LOGISTIC FUNCTION? J Bioinform Comput Biol 2011. [DOI: 10.1142/s0219720011005264] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
E-value guided extrapolation of protein domain annotation from libraries such as Pfam with the HMMER suite is indispensable for hypothesizing about the function of experimentally uncharacterized protein sequences. Since the recent release of HMMER3 does not supersede all functions of HMMER2, the latter will remain relevant for ongoing research as well as for the evaluation of annotations that reside in databases and in the literature. In HMMER2, the E-value is computed from the score via a logistic function or via a domain model-specific extreme value distribution (EVD); the lower of the two is returned as E-value for the domain hit in the query sequence. We find that, for thousands of domain models, this treatment results in switching from the EVD to the statistical model with the logistic function when scores grow (for Pfam release 23, 99% in the global mode and 75% in the fragment mode). If the score corresponding to the breakpoint results in an E-value above a user-defined threshold (e.g. 0.1), a critical score region with conflicting E-values from the logistic function (below the threshold) and from EVD (above the threshold) does exist. Thus, this switch will affect E-value guided annotation decisions in an automated mode. To emphasize, switching in the fragment mode is of no practical relevance since it occurs only at E-values far below 0.1. Unfortunately, a critical score region does exist for 185 domain models in the hmmpfam and 1,748 domain models in the hmmsearch global-search mode. For 145 out the respective 185 models, the critical score region is indeed populated by actual sequences. In total, 24.4% of their hits have a logistic function-derived E-value < 0.1 when the EVD provides an E-value > 0.1. We provide examples of false annotations and critically discuss the appropriateness of a logistic function as alternative to the EVD.
Collapse
Affiliation(s)
- WING-CHEONG WONG
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A *STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671, Singapore
| | - SEBASTIAN MAURER-STROH
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A *STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671, Singapore
- School of Biological Sciences (SBS), Nanyang Technological University (NTU), 60 Nanyang Drive, Singapore 63755, Singapore
| | - FRANK EISENHABER
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A *STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671, Singapore
- Department of Biological Sciences (DBS), National University of Singapore (NUS), 8 Medical Drive, Singapore 117597, Singapore
- School of Computer Engineering (SCE), Nanyang Technological University (NTU), 50 Nanyang Drive, Singapore 637553, Singapore
| |
Collapse
|
34
|
Park YJ, Pardon E, Wu M, Steyaert J, Hol WGJ. Crystal structure of a heterodimer of editosome interaction proteins in complex with two copies of a cross-reacting nanobody. Nucleic Acids Res 2011; 40:1828-40. [PMID: 22039098 PMCID: PMC3287191 DOI: 10.1093/nar/gkr867] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The parasite Trypanosoma brucei, the causative agent of sleeping sickness across sub-Saharan Africa, depends on a remarkable U-insertion/deletion RNA editing process in its mitochondrion. A approximately 20 S multi-protein complex, called the editosome, is an essential machinery for editing pre-mRNA molecules encoding the majority of mitochondrial proteins. Editosomes contain a common core of twelve proteins where six OB-fold interaction proteins, called A1-A6, play a crucial role. Here, we report the structure of two single-strand nucleic acid-binding OB-folds from interaction proteins A3 and A6 that surprisingly, form a heterodimer. Crystal growth required the assistance of an anti-A3 nanobody as a crystallization chaperone. Unexpectedly, this anti-A3 nanobody binds to both A3(OB) and A6, despite only ~40% amino acid sequence identity between the OB-folds of A3 and A6. The A3(OB)-A6 heterodimer buries 35% more surface area than the A6 homodimer. This is attributed mainly to the presence of a conserved Pro-rich loop in A3(OB). The implications of the A3(OB)-A6 heterodimer, and of a dimer of heterodimers observed in the crystals, for the architecture of the editosome are profound, resulting in a proposal of a 'five OB-fold center' in the core of the editosome.
Collapse
Affiliation(s)
- Young-Jun Park
- Department of Biochemistry, Biomolecular Structure Center, School of Medicine, University of Washington, PO Box 357742, Seattle WA 98195, USA
| | | | | | | | | |
Collapse
|
35
|
Peters JM, Vangeloff AD, Landick R. Bacterial transcription terminators: the RNA 3'-end chronicles. J Mol Biol 2011; 412:793-813. [PMID: 21439297 PMCID: PMC3622210 DOI: 10.1016/j.jmb.2011.03.036] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/14/2011] [Accepted: 03/16/2011] [Indexed: 01/01/2023]
Abstract
The process of transcription termination is essential to proper expression of bacterial genes and, in many cases, to the regulation of bacterial gene expression. Two types of bacterial transcriptional terminators are known to control gene expression. Intrinsic terminators dissociate transcription complexes without the assistance of auxiliary factors. Rho-dependent terminators are sites of dissociation mediated by an RNA helicase called Rho. Despite decades of study, the molecular mechanisms of both intrinsic and Rho-dependent termination remain uncertain in key details. Most knowledge is based on the study of a small number of model terminators. The extent of sequence diversity among functional terminators and the extent of mechanistic variation as a function of sequence diversity are largely unknown. In this review, we consider the current state of knowledge about bacterial termination mechanisms and the relationship between terminator sequence and steps in the termination mechanism.
Collapse
Affiliation(s)
- Jason M. Peters
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Abbey D. Vangeloff
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| |
Collapse
|
36
|
Mutagenesis-based evidence for an asymmetric configuration of the ring-shaped transcription termination factor Rho. J Mol Biol 2010; 405:497-518. [PMID: 21059356 DOI: 10.1016/j.jmb.2010.11.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 09/16/2010] [Accepted: 11/01/2010] [Indexed: 11/20/2022]
Abstract
Transcription termination factor Rho is an ATP-dependent ring-shaped molecular motor that tracks along RNA to dissociate RNA-DNA duplexes and transcription complexes in its path. The Rho hexamer contains two distinct sites for interaction with RNA. The primary binding site is composed of pyrimidine-specific binding clefts that are located in the N-terminal domains and anchor Rho to transcripts at C-rich Rut (Rho utilization) sites. Components of the secondary binding site (SBS) in the C-terminal domains directly couple RNA binding to ATP hydrolysis in order to translocate RNA through the Rho ring. Published crystal structures of RNA-bound Rho display distinct architectures ('trimer-of-dimers' or asymmetric hexamer) and SBS-RNA interaction networks that suggested conflicting models of RNA "handoff" or "escort" by the Rho subunits. To probe the mechanism of mechanochemical transduction in Rho, we have mutated into alanines (or glycines) the residues that make SBS contacts with RNA in the 'trimer-of-dimers' structure supporting the "handoff" model. We find that the resulting single-point mutants have similar RNA binding affinities but exhibit significantly different ATP hydrolysis, transcription termination, and RNA-DNA unwinding activities that are more compatible with the asymmetric Rho structure than with the 'trimer-of-dimers' structure and the resulting "handoff" model. We discuss our findings in connection with specific features of the asymmetric Rho structure yet argue that a simple RNA "escort" model is insufficient to account for all experimental evidence.
Collapse
|
37
|
Stitt BL, Xiao H. Conformation changes in E. coli Rho monitored by hydrogen/deuterium exchange and mass spectrometry: response to ligand binding. J Mol Biol 2010; 402:813-24. [PMID: 20708016 DOI: 10.1016/j.jmb.2010.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 07/21/2010] [Accepted: 08/02/2010] [Indexed: 11/26/2022]
Abstract
Escherichia coli Rho is a doughnut-shaped homohexameric ATP-dependent RNA-DNA helicase that releases newly synthesized RNA molecules from transcription complexes. Rho binds 60-80 bases of RNA among six primary RNA binding sites around the inside of its N-terminal crown; the RNA then passes through the central hole of the hexamer. Here it triggers ATP hydrolysis and is moved with respect to the protein. We study protein conformation changes upon ligand binding using amide proton hydrogen/deuterium exchange and mass spectrometry. Global-exchange studies indicate net mass differences of about 15 Da after 1 h of exchange in the presence--versus in the absence--of the ligand MgATP or the RNA poly(C). Sites of ligand-dependent exchange differences were localized by mass determination of the peptic peptides of Rho. A peptide of the N-terminal domain near the known primary RNA sites (aa 56-63) was protected from amide proton exchange in the presence of poly(C), as was a novel N-terminal domain peptide that is not near RNA in the crystal structures or in NMR structures with RNA oligomers (aa 37-46). This result may further define the primary interaction site of RNA with Rho. The Q-loop-containing peptide in the central hole of the protein that interacts with RNA was also protected by RNA (aa 271-286). The exchange rate of one peptide near the ATPase active site (aa 206-218) slowed in the presence of MgATP and increased in the presence of RNA. Overall, the results show changes in a few protein segments rather than a different overall conformation.
Collapse
Affiliation(s)
- Barbara L Stitt
- Department of Biochemistry and Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
| | | |
Collapse
|
38
|
Rabhi M, Rahmouni AR, Boudvillain M. Transcription Termination Factor Rho: A Ring-Shaped RNA Helicase from Bacteria. RNA HELICASES 2010. [DOI: 10.1039/9781849732215-00243] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Makhlouf Rabhi
- Centre de Biophysique Moléculaire (UPR4301) CNRS rue Charles Sadron 45071 Orléans cedex 2 France
- Ecole doctorale Sciences et Technologies, Université d’Orléans France
| | - A. Rachid Rahmouni
- Centre de Biophysique Moléculaire (UPR4301) CNRS rue Charles Sadron 45071 Orléans cedex 2 France
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire (UPR4301) CNRS rue Charles Sadron 45071 Orléans cedex 2 France
| |
Collapse
|
39
|
Two distantly homologous DnaG primases from Thermoanaerobacter tengcongensis exhibit distinct initiation specificities and priming activities. J Bacteriol 2010; 192:2670-81. [PMID: 20348261 DOI: 10.1128/jb.01511-09] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Primase, encoded by dnaG in bacteria, is a specialized DNA-dependent RNA polymerase that synthesizes RNA primers de novo for elongation by DNA polymerase. Genome sequence analysis has revealed two distantly related dnaG genes, TtdnaG and TtdnaG(2), in the thermophilic bacterium Thermoanaerobacter tengcongensis. Both TtDnaG (600 amino acids) and TtDnaG2 (358 amino acids) exhibit primase activities in vitro at a wide range of temperatures. Interestingly, the template recognition specificities of these two primases are quite distinctive. When trinucleotide-specific templates were tested, TtDnaG initiated RNA primer synthesis efficiently only on templates containing the trinucleotide 5'-CCC-3', not on the other 63 possible trinucleotides. When the 5'-CCC-3' sequence was flanked by additional cytosines or guanines, the initiation efficiency of TtDnaG increased remarkably. Significantly, TtDnaG could specifically and efficiently initiate RNA primer synthesis on a limited set of tetranucleotides composed entirely of cytosines and guanines, indicating that TtDnaG initiated RNA primer synthesis more preferably on GC-containing tetranucleotides. In contrast, it seemed that TtDnaG2 had no specific initiation nucleotides, as it could efficiently initiate RNA primer synthesis on all templates tested. The DNA binding affinity of TtDnaG2 was usually 10-fold higher than that of TtDnaG, which might correlate with its high activity but low template specificity. These distinct priming activities and specificities of TtDnaG and TtDnaG2 might shed new light on the diversity in the structure and function of the primases.
Collapse
|
40
|
Boudvillain M, Walmacq C, Schwartz A, Jacquinot F. Simple enzymatic assays for the in vitro motor activity of transcription termination factor Rho from Escherichia coli. Methods Mol Biol 2010; 587:137-154. [PMID: 20225147 DOI: 10.1007/978-1-60327-355-8_10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The transcription termination factor Rho from Escherichia coli is a ring-shaped homo-hexameric protein that preferentially interacts with naked cytosine-rich Rut (Rho utilization) regions of nascent RNA transcripts. Once bound to the RNA chain, Rho uses ATP as an energy source to produce mechanical work and disruptive forces that ultimately lead to the dissociation of the ternary transcription complex. Although transcription termination assays have been useful to study Rho activity in various experimental contexts, they do not report directly on Rho mechanisms and kinetics. Here, we describe complementary ATP-dependent RNA-DNA helicase and streptavidin displacement assays that can be used to monitor in vitro Rho's motor activity in a more direct and quantitative manner.
Collapse
Affiliation(s)
- Marc Boudvillain
- Centre de Biophysique Moleculaire (UPR4301), CNRS, Orleans cedex 2, Orleans, France
| | | | | | | |
Collapse
|
41
|
Schwartz A, Rabhi M, Jacquinot F, Margeat E, Rahmouni AR, Boudvillain M. A stepwise 2'-hydroxyl activation mechanism for the bacterial transcription termination factor Rho helicase. Nat Struct Mol Biol 2009; 16:1309-16. [PMID: 19915588 DOI: 10.1038/nsmb.1711] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 09/23/2009] [Indexed: 01/02/2023]
Abstract
The bacterial Rho factor is a ring-shaped ATP-dependent helicase that tracks along RNA transcripts and disrupts RNA-DNA duplexes and transcription complexes in its path. Using combinatorial nucleotide analog interference mapping (NAIM), we explore the topology and dynamics of functional Rho-RNA complexes and reveal the RNA-dependent stepping mechanism of Rho helicase. Periodic Gaussian distributions of NAIM signals show that Rho forms uneven productive interactions with the track nucleotides and disrupts RNA-DNA duplexes in a succession of large ( approximately 7-nucleotide-long) discrete steps triggered by 2'-hydroxyl activation events. This periodic 2'-OH-dependent activation does not depend on the RNA-DNA pairing energy but is finely tuned by sequence-dependent interactions with the RNA track. These features explain the strict RNA specificity and contextual efficiency of the enzyme and provide a new paradigm for conditional tracking by a helicase ring.
Collapse
Affiliation(s)
- Annie Schwartz
- Centre Nationale de la Recherche Scientifique (CNRS) UPR4301, Centre de Biophysique Moléculaire, Orléans, France
| | | | | | | | | | | |
Collapse
|
42
|
Warren EM, Huang H, Fanning E, Chazin WJ, Eichman BF. Physical interactions between Mcm10, DNA, and DNA polymerase alpha. J Biol Chem 2009; 284:24662-72. [PMID: 19608746 DOI: 10.1074/jbc.m109.020438] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Mcm10 is an essential eukaryotic protein required for the initiation and elongation phases of chromosomal replication. Specifically, Mcm10 is required for the association of several replication proteins, including DNA polymerase alpha (pol alpha), with chromatin. We showed previously that the internal (ID) and C-terminal (CTD) domains of Mcm10 physically interact with both single-stranded (ss) DNA and the catalytic p180 subunit of pol alpha. However, the mechanism by which Mcm10 interacts with pol alpha on and off DNA is unclear. As a first step toward understanding the structural details for these critical intermolecular interactions, x-ray crystallography and NMR spectroscopy were used to map the binary interfaces between Mcm10-ID, ssDNA, and p180. The crystal structure of an Mcm10-ID*ssDNA complex confirmed and extended our previous evidence that ssDNA binds within the oligonucleotide/oligosaccharide binding-fold cleft of Mcm10-ID. We show using NMR chemical shift perturbation and fluorescence spectroscopy that p180 also binds to the OB-fold and that ssDNA and p180 compete for binding to this motif. In addition, we map a minimal Mcm10 binding site on p180 to a small region within the p180 N-terminal domain (residues 286-310). These findings, together with data for DNA and p180 binding to an Mcm10 construct that contains both the ID and CTD, provide the first mechanistic insight into how Mcm10 might use a handoff mechanism to load and stabilize pol alpha within the replication fork.
Collapse
Affiliation(s)
- Eric M Warren
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37232, USA
| | | | | | | | | |
Collapse
|
43
|
Pestryakov PE, Lavrik OI. Mechanisms of single-stranded DNA-binding protein functioning in cellular DNA metabolism. BIOCHEMISTRY (MOSCOW) 2009; 73:1388-404. [PMID: 19216707 DOI: 10.1134/s0006297908130026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review deals with analysis of mechanisms involved in coordination of DNA replication and repair by SSB proteins; characteristics of eukaryotic, prokaryotic, and archaeal SSB proteins are considered, which made it possible to distinguish general mechanisms specific for functioning of proteins from organisms of different life domains. Mechanisms of SSB protein interactions with DNA during metabolism of the latter are studied; structural organization of the SSB protein complexes with DNA, as well as structural and functional peculiarities of different SSB proteins are analyzed.
Collapse
Affiliation(s)
- P E Pestryakov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | | |
Collapse
|
44
|
Abstract
Many protein-RNA recognition events are known to exhibit conformational changes from qualitative observations of individual complexes. However, a quantitative estimation of conformational changes is required if protein-RNA docking and template-based methods for RNA binding site prediction are to be developed. This study presents the first quantitative evaluation of conformational changes that occur when proteins bind RNA. The analysis of twelve RNA-binding proteins in the bound and unbound states using error-scaled difference distance matrices is presented. The binding site residues are mapped to each structure, and the conformational changes that affect these residues are evaluated. Of the twelve proteins four exhibit greater movements in nonbinding site residues, and a further four show the greatest movements in binding site residues. The remaining four proteins display no significant conformational change. When interface residues are found to be in conformationally variable regions of the protein they are typically seen to move less than 2 A between the bound and unbound conformations. The current data indicate that conformational changes in the binding site residues of RNA binding proteins may not be as significant as previously suggested, but a larger data set is required before wider conclusions may be drawn. The implications of the observed conformational changes for protein function prediction are discussed.
Collapse
Affiliation(s)
- Jonathan J Ellis
- Department of Biochemistry, University of Sussex, Falmer, BN1 9RH, United Kingdom.
| | | |
Collapse
|
45
|
Abstract
We analyze the protein–RNA interfaces in 81 transient binary complexes taken from the Protein Data Bank. Those with tRNA or duplex RNA are larger than with single-stranded RNA, and comparable in size to protein–DNA interfaces. The protein side bears a strong positive electrostatic potential and resembles protein–DNA interfaces in its amino acid composition. On the RNA side, the phosphate contributes less, and the sugar much more, to the interaction than in protein–DNA complexes. On average, protein–RNA interfaces contain 20 hydrogen bonds, 7 that involve the phosphates, 5 the sugar 2′OH, and 6 the bases, and 32 water molecules. The average H-bond density per unit buried surface area is less with tRNA or single-stranded RNA than with duplex RNA. The atomic packing is also less compact in interfaces with tRNA. On the protein side, the main chain NH and Arg/Lys side chains account for nearly half of all H-bonds to RNA; the main chain CO and side chain acceptor groups, for a quarter. The 2′OH is a major player in protein–RNA recognition, and shape complementarity an important determinant, whereas electrostatics and direct base–protein interactions play a lesser part than in protein–DNA recognition.
Collapse
Affiliation(s)
- Ranjit Prasad Bahadur
- School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
| | | | | |
Collapse
|
46
|
Rouda S, Skordalakes E. Structure of the RNA-binding domain of telomerase: implications for RNA recognition and binding. Structure 2008; 15:1403-12. [PMID: 17997966 DOI: 10.1016/j.str.2007.09.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Revised: 09/03/2007] [Accepted: 09/06/2007] [Indexed: 12/22/2022]
Abstract
Telomerase, a ribonucleoprotein complex, replicates the linear ends of eukaryotic chromosomes, thus taking care of the "end of replication problem." TERT contains an essential and universally conserved domain (TRBD) that makes extensive contacts with the RNA (TER) component of the holoenzyme, and this interaction is thought to facilitate TERT/TER assembly and repeat-addition processivity. Here, we present a high-resolution structure of TRBD from Tetrahymena thermophila. The nearly all-helical structure comprises a nucleic acid-binding fold suitable for TER binding. An extended pocket on the surface of the protein, formed by two conserved motifs (CP and T motifs) comprises TRBD's RNA-binding pocket. The width and the chemical nature of this pocket suggest that it binds both single- and double-stranded RNA, possibly stem I, and the template boundary element (TBE). Moreover, the structure provides clues into the role of this domain in TERT/TER stabilization and telomerase repeat-addition processivity.
Collapse
Affiliation(s)
- Susan Rouda
- Gene Expression and Regulation Program, The Wistar Institute, University of Pennsylvania, 3601 Spruce Street, Philadelphia, PA 19104, USA
| | | |
Collapse
|
47
|
Eldridge AM, Wuttke DS. Probing the mechanism of recognition of ssDNA by the Cdc13-DBD. Nucleic Acids Res 2008; 36:1624-33. [PMID: 18250086 PMCID: PMC2275150 DOI: 10.1093/nar/gkn017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Saccharomyces cerevisiae protein Cdc13 tightly and specifically binds the conserved G-rich single-stranded overhang at telomeres and plays an essential role in telomere end-protection and length regulation. The 200 residue DNA-binding domain of Cdc13 (Cdc13-DBD) binds an 11mer single-stranded representative of the yeast telomeric sequence [Tel11, d(GTGTGGGTGTG)] with a 3 pM affinity and specificity for three bases (underlined) at the 5′ end. The structure of the Cdc13-DBD bound to Tel11 revealed a large, predominantly aromatic protein interface with several unusual features. The DNA adopts an irregular, extended structure, and the binding interface includes a long (∼30 amino acids) structured loop between strands β2-β3 (L2–3) of an OB-fold. To investigate the mechanism of ssDNA binding, we studied the free and bound states of Cdc13-DBD using NMR spectroscopy. Chemical shift changes indicate that the basic topology of the domain, including L2–3, is essentially intact in the free state. Changes in slow and intermediate time scale dynamics, however, occur in L2–3, while conformational changes distant from the DNA interface suggest an induced fit mechanism for binding in the ‘hot spot’ for binding affinity and specificity. These data point to an overall binding mechanism well adapted to the heterogeneous nature of yeast telomeres.
Collapse
Affiliation(s)
- Aimee M Eldridge
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
| | | |
Collapse
|
48
|
Tsonis PA, Dwivedi B. Molecular mimicry: structural camouflage of proteins and nucleic acids. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1783:177-87. [PMID: 18068679 DOI: 10.1016/j.bbamcr.2007.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 11/05/2007] [Accepted: 11/06/2007] [Indexed: 11/28/2022]
Abstract
When it comes to protein specificity and function their three-dimensional structure is the ultimate determinant. Thus, sequences that participate in key parts, such as catalytic sites or DNA binding have been favored and maintained highly conserved during evolution. However, in a reversal of fortune, selection has favored conservation of shapes over sequence, especially when proteins look like nucleic acids. Proteins from pathogens evade the host's defenses because they are shaped as DNA; others use such a disguise for transcriptional regulation. Several factors are tRNA look-alikes so that they can efficiently control the process of protein synthesis. Molecular mimicry among RNAs could result in a new unexplored level in gene regulation. This comprehensive review outlines this important area and aims to emphasize that molecular mimicry could in fact be more widespread than initially thought and eventually adds a new layer of genetic regulation.
Collapse
|
49
|
Chalissery J, Banerjee S, Bandey I, Sen R. Transcription termination defective mutants of Rho: role of different functions of Rho in releasing RNA from the elongation complex. J Mol Biol 2007; 371:855-72. [PMID: 17599352 PMCID: PMC1950744 DOI: 10.1016/j.jmb.2007.06.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 06/01/2007] [Accepted: 06/01/2007] [Indexed: 11/24/2022]
Abstract
The transcription termination factor Rho of Escherichia coli is a RNA binding protein which can translocate along the RNA and unwind the RNA:DNA hybrid using the RNA-dependent ATPase activity. In order to investigate the involvement of each of these functions in releasing RNA from the elongation complex, we have isolated different termination defective mutants of Rho by random mutagenesis, characterized them for their different functions and established the structure–function correlations from the available structural data of Rho. These mutations are located within the two domains; the N-terminal RNA binding domain (G51V, G53V, and Y80C) and in the C-terminal ATP binding domain (Y274D, P279S, P279L, G324D, N340S, I382N) including the two important structural elements, the Q-loop (P279S, P279L) and R-loop (G324D). Termination defects of the mutants in primary RNA binding domain and Q-loop could not be restored under any conditions that we tested and these were also defective for most of the other functions of Rho. The termination defects of the mutants (Y274D, G324D and N340S), which were mainly defective for secondary RNA binding and likely defective for translocase activity, could be restored under relaxed in vitro conditions. We also show that a mutation in a primary RNA binding domain (Y80C) can cause a defect in ATP binding and induce distinct conformational changes in the distal C-terminal domain, and these allosteric effects are not predictable from the crystal structure. We conclude that the interactions in the primary RNA binding domain and in the Q-loop are mandatory for RNA release to occur and propose that the interactions in the primary RNA binding modulate most of the other functions of Rho allosterically. The rate of ATP hydrolysis regulates the processivity of translocation along the RNA and is directly correlated with the efficiency of RNA release. NusG improves the speed of RNA release and is not involved in any other step.
Collapse
|
50
|
Skordalakes E, Berger JM. Structural insights into RNA-dependent ring closure and ATPase activation by the Rho termination factor. Cell 2006; 127:553-64. [PMID: 17081977 DOI: 10.1016/j.cell.2006.08.051] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 07/25/2006] [Accepted: 08/25/2006] [Indexed: 11/16/2022]
Abstract
Hexameric helicases and translocases are required for numerous essential nucleic-acid transactions. To better understand the mechanisms by which these enzymes recognize target substrates and use nucleotide hydrolysis to power molecular movement, we have determined the structure of the Rho transcription termination factor, a hexameric RNA/DNA helicase, with single-stranded RNA bound to the motor domains of the protein. The structure reveals a closed-ring "trimer of dimers" conformation for the hexamer that contains an unanticipated arrangement of conserved loops required for nucleic-acid translocation. RNA extends across a shallow intersubunit channel formed by conserved amino acids required for RNA-stimulated ATP hydrolysis and translocation and directly contacts a conserved lysine, just upstream of the catalytic GKT triad, in the phosphate-binding (P loop) motif of the ATP-binding pocket. The structure explains the molecular effects of numerous mutations and provides new insights into the links between substrate recognition, ATP turnover, and coordinated strand movement.
Collapse
Affiliation(s)
- Emmanuel Skordalakes
- Department of Molecular and Cell Biology, University of California, Berkeley, 327B Hildebrand Hall #3206, Berkeley, CA 94720, USA
| | | |
Collapse
|