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Worst EG, Finkler M, Schenkelberger M, Kurt Ö, Helms V, Noireaux V, Ott A. A Methylation-Directed, Synthetic Pap Switch Based on Self-Complementary Regulatory DNA Reconstituted in an All E. coli Cell-Free Expression System. ACS Synth Biol 2021; 10:2725-2739. [PMID: 34550672 DOI: 10.1021/acssynbio.1c00326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyelonephritis-associated pili (pap) enable migration of the uropathogenic Escherichia coli strain (UPEC) through the urinary tract. UPEC can switch between a stable 'ON phase' where the corresponding pap genes are expressed and a stable 'OFF phase' where their transcription is repressed. Hereditary DNA methylation of either one of two GATC motives within the regulatory region stabilizes the respective phase over many generations. The underlying molecular mechanism is only partly understood. Previous investigations suggest that in vivo phase-variation stability results from cooperative action of the transcriptional regulators Lrp and PapI. Here, we use an E. coli cell-free expression system to study molecular functions of the pap regulatory region based on a specially designed, synthetic construct flanked by two reporter genes encoding fluorescent proteins for simple readout. On the basis of our observations we suggest that besides Lrp, the conformation of the self-complementary regulatory DNA plays a strong role in the regulation of phase-variation. Our work not only contributes to better understand the phase variation mechanism, but it represents a successful start for mimicking stable, hereditary, and strong expression control based on methylation. The conformation of the regulatory DNA corresponds to a Holliday junction. Gene expression must be expected to respond if opposite arms of the junction are drawn outward.
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Affiliation(s)
- Emanuel G. Worst
- Universität des Saarlandes, Center for Biophysics, Saarbrücken, 66123, Germany
| | - Marc Finkler
- Universität des Saarlandes, Center for Biophysics, Saarbrücken, 66123, Germany
| | - Marc Schenkelberger
- Universität des Saarlandes, Center for Biophysics, Saarbrücken, 66123, Germany
| | - Ömer Kurt
- Universität des Saarlandes, Center for Biophysics, Saarbrücken, 66123, Germany
| | - Volkhard Helms
- Universität des Saarlandes, Center for Bioinformatics, Saarbrücken, 66041, Germany
| | - Vincent Noireaux
- University of Minnesota, School of Physics and Astronomy, Minneapolis, Minnesota 55455, United States
| | - Albrecht Ott
- Universität des Saarlandes, Center for Biophysics, Saarbrücken, 66123, Germany
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2
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Ziegler CA, Freddolino PL. The leucine-responsive regulatory proteins/feast-famine regulatory proteins: an ancient and complex class of transcriptional regulators in bacteria and archaea. Crit Rev Biochem Mol Biol 2021; 56:373-400. [PMID: 34151666 DOI: 10.1080/10409238.2021.1925215] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Since the discovery of the Escherichia coli leucine-responsive regulatory protein (Lrp) almost 50 years ago, hundreds of Lrp homologs have been discovered, occurring in 45% of sequenced bacteria and almost all sequenced archaea. Lrp-like proteins are often referred to as the feast/famine regulatory proteins (FFRPs), reflecting their common regulatory roles. Acting as either global or local transcriptional regulators, FFRPs detect the environmental nutritional status by sensing small effector molecules (usually amino acids) and regulate the expression of genes involved in metabolism, virulence, motility, nutrient transport, stress tolerance, and antibiotic resistance to implement appropriate behaviors for the specific ecological niche of each organism. Despite FFRPs' complexity, a significant role in gene regulation, and prevalence throughout prokaryotes, the last comprehensive review on this family of proteins was published about a decade ago. In this review, we integrate recent notable findings regarding E. coli Lrp and other FFRPs across bacteria and archaea with previous observations to synthesize a more complete view on the mechanistic details and biological roles of this ancient class of transcription factors.
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Affiliation(s)
- Christine A Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
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Zhou J, Horton JR, Blumenthal RM, Zhang X, Cheng X. Clostridioides difficile specific DNA adenine methyltransferase CamA squeezes and flips adenine out of DNA helix. Nat Commun 2021; 12:3436. [PMID: 34103525 PMCID: PMC8187626 DOI: 10.1038/s41467-021-23693-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/13/2021] [Indexed: 12/13/2022] Open
Abstract
Clostridioides difficile infections are an urgent medical problem. The newly discovered C. difficile adenine methyltransferase A (CamA) is specified by all C. difficile genomes sequenced to date (>300), but is rare among other bacteria. CamA is an orphan methyltransferase, unassociated with a restriction endonuclease. CamA-mediated methylation at CAAAAA is required for normal sporulation, biofilm formation, and intestinal colonization by C. difficile. We characterized CamA kinetic parameters, and determined its structure bound to DNA containing the recognition sequence. CamA contains an N-terminal domain for catalyzing methyl transfer, and a C-terminal DNA recognition domain. Major and minor groove DNA contacts in the recognition site involve base-specific hydrogen bonds, van der Waals contacts and the Watson-Crick pairing of a rearranged A:T base pair. These provide sufficient sequence discrimination to ensure high specificity. Finally, the surprisingly weak binding of the methyl donor S-adenosyl-L-methionine (SAM) might provide avenues for inhibiting CamA activity using SAM analogs.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Zamora M, Ziegler CA, Freddolino PL, Wolfe AJ. A Thermosensitive, Phase-Variable Epigenetic Switch: pap Revisited. Microbiol Mol Biol Rev 2020; 84:e00030-17. [PMID: 32727743 PMCID: PMC7392537 DOI: 10.1128/mmbr.00030-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
It has been more than a decade since the last comprehensive review of the phase-variable uropathogen-associated pyelonephritis-associated pilus (pap) genetic switch. Since then, important data have come to light, including additional factors that regulate pap expression, better characterization of H-NS regulation, the structure of the Lrp octamer in complex with pap regulatory DNA, the temperature-insensitive phenotype of a mutant lacking the acetyltransferase RimJ, evidence that key components of the regulatory machinery are acetylated, and new insights into the role of DNA binding by key regulators in shaping both the physical structure and regulatory state of the papI and papBA promoters. This review revisits pap, integrating these newer observations with older ones to produce a new model for the concerted behavior of this virulence-regulatory region.
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Affiliation(s)
- Mario Zamora
- Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
- Department of Microbiology and Immunology, Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
| | - Christine A Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alan J Wolfe
- Department of Microbiology and Immunology, Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
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sRNA-Mediated Regulation of P-Fimbriae Phase Variation in Uropathogenic Escherichia coli. PLoS Pathog 2015; 11:e1005109. [PMID: 26291711 PMCID: PMC4546395 DOI: 10.1371/journal.ppat.1005109] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 07/24/2015] [Indexed: 12/21/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) are capable of occupying physiologically distinct intracellular and extracellular niches within the urinary tract. This feat requires the timely regulation of gene expression and small RNAs (sRNAs) are known to mediate such rapid adjustments in response to changing environmental cues. This study aimed to uncover sRNA-mediated gene regulation in the UPEC strain UTI89, during infection of bladder epithelial cells. Hfq is an RNA chaperone known to facilitate and stabilize sRNA and target mRNA interactions with bacterial cells. The co-immunoprecipitation and high throughput RNA sequencing of Hfq bound sRNAs performed in this study, revealed distinct sRNA profiles in UPEC in the extracellular and intracellular environments. Our findings emphasize the importance of studying regulatory sRNAs in a biologically relevant niche. This strategy also led to the discovery of a novel virulence-associated trans-acting sRNA—PapR. Deletion of papR was found to enhance adhesion of UTI89 to both bladder and kidney cell lines in a manner independent of type-1 fimbriae. We demonstrate PapR mediated posttranscriptional repression of the P-fimbriae phase regulator gene papI and postulate a role for such regulation in fimbrial cross-talk at the population level in UPEC. Our results further implicate the Leucine responsive protein (LRP) as a transcriptional activator regulating PapR expression. Our study reports, for the first time, a role for sRNAs in regulation of P-fimbriae phase variation and emphasizes the importance of studying pathogenesis-specific sRNAs within a relevant biological niche. Recent years have seen an increasing emphasis placed on the role of small RNAs (sRNAs) in the regulation of bacterial gene expression and stress adaptation. The advent of high-throughput sequencing methods has now made it possible to directly monitor the appearance of potentially virulence-associated sRNAs that may contribute to rapid adaptation of the pathogen to a changing environment during infection. Uropathogenic Escherichia coli (UPEC) are presumably exposed to a deluge of stimuli from epithelial cell contact, urine and host immune factors and we asked if any regulatory sRNAs would play a role in the transition of UPEC from the extracellular niche to the intracellular one. This study employs co-immunoprecipitation using the RNA chaperone Hfq to identify novel virulence-associated sRNAs in intracellular UPEC, followed by high-throughput RNA-seq. We report the identification of a novel sRNA that we designate PapR (P-fimbriae regulator) and elaborate on this discovery by demonstrating a role for PapR in regulation of P-fimbriae—a UPEC surface virulence factor. The results presented in this study offer new insights into the molecular mechanisms of UPEC pathogenesis and a role for sRNA mediated regulation of virulence factors.
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Melekhov VV, Shvyreva US, Timchenko AA, Tutukina MN, Preobrazhenskaya EV, Burkova DV, Artiukhov VG, Ozoline ON, Antipov SS. Modes of Escherichia coli Dps Interaction with DNA as Revealed by Atomic Force Microscopy. PLoS One 2015; 10:e0126504. [PMID: 25978038 PMCID: PMC4433220 DOI: 10.1371/journal.pone.0126504] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 04/02/2015] [Indexed: 11/18/2022] Open
Abstract
Multifunctional protein Dps plays an important role in iron assimilation and a crucial role in bacterial genome packaging. Its monomers form dodecameric spherical particles accumulating ~400 molecules of oxidized iron ions within the protein cavity and applying a flexible N-terminal ends of each subunit for interaction with DNA. Deposition of iron is a well-studied process by which cells remove toxic Fe2+ ions from the genetic material and store them in an easily accessible form. However, the mode of interaction with linear DNA remained mysterious and binary complexes with Dps have not been characterized so far. It is widely believed that Dps binds DNA without any sequence or structural preferences but several lines of evidence have demonstrated its ability to differentiate gene expression, which assumes certain specificity. Here we show that Dps has a different affinity for the two DNA fragments taken from the dps gene regulatory region. We found by atomic force microscopy that Dps predominantly occupies thermodynamically unstable ends of linear double-stranded DNA fragments and has high affinity to the central part of the branched DNA molecule self-assembled from three single-stranded oligonucleotides. It was proposed that Dps prefers binding to those regions in DNA that provide more contact pads for the triad of its DNA-binding bundle associated with one vertex of the protein globule. To our knowledge, this is the first study revealed the nucleoid protein with an affinity to branched DNA typical for genomic regions with direct and inverted repeats. As a ubiquitous feature of bacterial and eukaryotic genomes, such structural elements should be of particular care, but the protein system evolutionarily adapted for this function is not yet known, and we suggest Dps as a putative component of this system.
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Affiliation(s)
- Vladislav V. Melekhov
- Department of Cell Biology, Pushchino State Institute of Natural Sciences, Pushchino, Moscow Region, Russian Federation
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | - Uliana S. Shvyreva
- Department of Functional Genomics and Cellular Stress, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | - Alexander A. Timchenko
- Department of Physics of Nucleoproteids, Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | - Maria N. Tutukina
- Department of Cell Biology, Pushchino State Institute of Natural Sciences, Pushchino, Moscow Region, Russian Federation
- Department of Functional Genomics and Cellular Stress, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | | | - Diana V. Burkova
- Department of biophysics and biotechnology, Voronezh State University, Voronezh, Russian Federation
| | - Valiriy G. Artiukhov
- Department of biophysics and biotechnology, Voronezh State University, Voronezh, Russian Federation
| | - Olga N. Ozoline
- Department of Cell Biology, Pushchino State Institute of Natural Sciences, Pushchino, Moscow Region, Russian Federation
- Department of Functional Genomics and Cellular Stress, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
- * E-mail:
| | - Sergey S. Antipov
- Department of Cell Biology, Pushchino State Institute of Natural Sciences, Pushchino, Moscow Region, Russian Federation
- Department of Functional Genomics and Cellular Stress, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
- Department of biophysics and biotechnology, Voronezh State University, Voronezh, Russian Federation
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Horton JR, Zhang X, Blumenthal RM, Cheng X. Structures of Escherichia coli DNA adenine methyltransferase (Dam) in complex with a non-GATC sequence: potential implications for methylation-independent transcriptional repression. Nucleic Acids Res 2015; 43:4296-308. [PMID: 25845600 PMCID: PMC4417163 DOI: 10.1093/nar/gkv251] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 11/21/2014] [Accepted: 03/11/2015] [Indexed: 12/31/2022] Open
Abstract
DNA adenine methyltransferase (Dam) is widespread and conserved among the γ-proteobacteria. Methylation of the Ade in GATC sequences regulates diverse bacterial cell functions, including gene expression, mismatch repair and chromosome replication. Dam also controls virulence in many pathogenic Gram-negative bacteria. An unexplained and perplexing observation about Escherichia coli Dam (EcoDam) is that there is no obvious relationship between the genes that are transcriptionally responsive to Dam and the promoter-proximal presence of GATC sequences. Here, we demonstrate that EcoDam interacts with a 5-base pair non-cognate sequence distinct from GATC. The crystal structure of a non-cognate complex allowed us to identify a DNA binding element, GTYTA/TARAC (where Y = C/T and R = A/G). This element immediately flanks GATC sites in some Dam-regulated promoters, including the Pap operon which specifies pyelonephritis-associated pili. In addition, Dam interacts with near-cognate GATC sequences (i.e. 3/4-site ATC and GAT). Taken together, these results imply that Dam, in addition to being responsible for GATC methylation, could also function as a methylation-independent transcriptional repressor.
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Affiliation(s)
- John R Horton
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Xing Zhang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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8
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Monitoring F1651 P-like fimbria expression at the single-cell level reveals a highly heterogeneous phenotype. Infect Immun 2015; 83:1929-39. [PMID: 25712930 DOI: 10.1128/iai.02510-14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 02/16/2015] [Indexed: 11/20/2022] Open
Abstract
F1651 and the pyelonephritis-associated pili (Pap) are two members of the type P family of adhesive factors. They play a key role in establishing disease caused by extraintestinal pathogenic Escherichia coli (ExPEC) strains in animals and humans. Both F1651 and Pap are under the control of an epigenetic and reversible switch that defines the number of fimbriated (ON) and afimbriated (OFF) cells within a clonal population. Using the Gfp reporter system, we monitored in vitro the level of fluorescence intensity corresponding to the F1651 and Pap fimbrial synthesis. Monitoring individual Escherichia coli cells by flow cytometry and by real-time fluorescence microscopy, we identified cells associated with a low or high level of fluorescence intensity and a large amount of cells with partial levels of fluorescence, mostly present in the F1651 system. This mixed population identified through fluorescence intensity could be attributed to the high switching rate previously observed in F1651-positive bacteria. The fimbrial heterogeneous phenotype for these ExPEC could represent increased fitness in unpredictable environments. Our study illustrates that within the large repertoire of fimbrial variants such as the well-characterized Pap, F1651 is an exquisite example of regulatory expression that arms the bacterium with strategies for surviving in more than one particular environment.
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Abstract
Contrary to the traditional view that bacterial populations are clonal, single-cell analysis reveals that phenotypic heterogeneity is common in bacteria. Formation of distinct bacterial lineages appears to be frequent during adaptation to harsh environments, including the colonization of animals by bacterial pathogens. Formation of bacterial subpopulations is often controlled by epigenetic mechanisms that generate inheritable phenotypic diversity without altering the DNA sequence. Such mechanisms are diverse, ranging from relatively simple feedback loops to complex self-perpetuating DNA methylation patterns.
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Affiliation(s)
- Josep Casadesús
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41080 Seville, Spain.
| | - David A Low
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106.
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10
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Oza JP, Sowers KR, Perona JJ. Linking energy production and protein synthesis in hydrogenotrophic methanogens. Biochemistry 2012; 51:2378-89. [PMID: 22401293 DOI: 10.1021/bi300106p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydrogenotrophic methanogens possessing the hydrogen-dependent dehydrogenase Hmd also encode paralogs of this protein whose function is poorly understood. Here we present biochemical evidence that the two inactive Hmd paralogs of Methanocaldococcus jannaschii, HmdII and HmdIII, form binary and ternary complexes with several components of the protein translation apparatus. HmdII and HmdIII, but not the active dehydrogenase Hmd, bind with micromolar binding affinities to a number of tRNAs and form ternary complexes with tRNA(Pro) and prolyl-tRNA synthetase (ProRS). Fluorescence spectroscopy experiments also suggest that binding of HmdII and ProRS involves distinct binding determinants on the tRNA. These biochemical data suggest the possibility of a regulatory link between energy production and protein translation pathways that may allow a rapid cellular response to altered environmental conditions.
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Affiliation(s)
- Javin P Oza
- Interdepartmental Program in Biomolecular Science and Engineering, University of California, Santa Barbara, Santa Barbara, California 93106-9510, United States
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Graveline R, Mourez M, Hancock MA, Martin C, Boisclair S, Harel J. Lrp-DNA complex stability determines the level of ON cells in type P fimbriae phase variation. Mol Microbiol 2011; 81:1286-99. [PMID: 21752106 DOI: 10.1111/j.1365-2958.2011.07761.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
F165(1) and the pyelonephritis-associated pili (Pap) are two members of the type P family of adhesive factors that play a key role in the establishment of disease caused by extraintestinal Escherichia coli (ExPEC) strains. They are both under the control of an epigenetic and reversible switch that defines the number of fimbriated (ON) and afimbriated (OFF) cells within a clonal population. Our present study demonstrates that the high level of ON cells found during F165(1) phase variation is due to altered stability of the DNA complex formed by the leucine-responsive regulatory protein (Lrp) at its repressor binding sites 1-3; after each cell cycle, complex formation is also modulated by the local regulator FooI (homologue to PapI) which promotes the transit of Lrp towards its activator binding sites 4-6. Furthermore, we identified two nucleotides (T490, G508) surrounding the Lrp binding site 1 that are critical to maintaining a high OFF to ON switch rate during F165(1) phase variation, as well as switching Pap fimbriae towards the OFF state.
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Affiliation(s)
- Richard Graveline
- Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
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