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Krusenstjerna AC, Jusufovic N, Saylor TC, Stevenson B. DnaA modulates the gene expression and morphology of the Lyme disease spirochete. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.08.598065. [PMID: 38895450 PMCID: PMC11185795 DOI: 10.1101/2024.06.08.598065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
All bacteria encode a multifunctional DNA-binding protein, DnaA, which initiates chromosomal replication. Despite having the most complex, segmented bacterial genome, little is known about Borrelia burgdorferi DnaA and its role in maintaining the spirochete's physiology. In this work we utilized inducible CRISPR-interference and overexpression to modulate cellular levels of DnaA to better understand this essential protein. Dysregulation of DnaA, either up or down, increased or decreased cell lengths, respectively, while also significantly slowing replication rates. Using fluorescent microscopy, we found the DnaA CRISPRi mutants had increased numbers of chromosomes with irregular spacing patterns. DnaA-depleted spirochetes also exhibited a significant defect in helical morphology. RNA-seq of the conditional mutants showed significant changes in the levels of transcripts involved with flagellar synthesis, elongation, cell division, virulence, and other functions. These findings demonstrate that the DnaA plays a commanding role in maintaining borrelial growth dynamics and protein expression, which are essential for the survival of the Lyme disease spirochete. IMPORTANCE Lyme disease is the most prevalent tick-borne infection in the Northern Hemisphere. Borrelia burgdorferi , the causative spirochete bacteria, has been maintained in nature for millennia in a consistent enzootic cycle between Ixodes ticks and various small vertebrate hosts. During the tick's blood meal, B. burgdorferi substantially increases its replication rate, alters its repertoire of outer surface proteins, and disseminates into the new vertebrate host. Across eubacteria, DnaA is the master regulatory protein that initiates chromosomal replication and acts as a transcription factor to regulate specific pathways. Here, we describe the roles that B. burgdorferi DnaA has on the physiology and gene expression of this medically important pathogen.
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Stringer AM, Fitzgerald DM, Wade JT. Mapping the Escherichia coli DnaA-binding landscape reveals a preference for binding pairs of closely spaced DNA sites. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001474. [PMID: 39012340 PMCID: PMC11317965 DOI: 10.1099/mic.0.001474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/14/2024] [Indexed: 07/17/2024]
Abstract
DnaA is a widely conserved DNA-binding protein that is essential for the initiation of DNA replication in many bacterial species, including Escherichia coli. Cooperative binding of ATP-bound DnaA to multiple 9mer sites ('DnaA boxes') at the origin of replication results in local unwinding of the DNA and recruitment of the replication machinery. DnaA also functions as a transcription regulator by binding to DNA sites upstream of target genes. Previous studies have identified many sites of direct positive and negative regulation by E. coli DnaA. Here, we use a ChIP-seq to map the E. coli DnaA-binding landscape. Our data reveal a compact regulon for DnaA that coordinates the initiation of DNA replication with expression of genes associated with nucleotide synthesis, replication, DNA repair and RNA metabolism. We also show that DnaA binds preferentially to pairs of DnaA boxes spaced 2 or 3 bp apart. Mutation of either the upstream or downstream site in a pair disrupts DnaA binding, as does altering the spacing between sites. We conclude that binding of DnaA at almost all target sites requires a dimer of DnaA, with each subunit making critical contacts with a DnaA box.
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Affiliation(s)
- Anne M. Stringer
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Devon M. Fitzgerald
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany, New York, USA
| | - Joseph T. Wade
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany, New York, USA
- RNA Institute, University at Albany, SUNY, Albany, New York, USA
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Elevated Levels of the Escherichia coli nrdAB-Encoded Ribonucleotide Reductase Counteract the Toxicity Caused by an Increased Abundance of the β Clamp. J Bacteriol 2021; 203:e0030421. [PMID: 34543109 DOI: 10.1128/jb.00304-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Expression of the Escherichia coli dnaN-encoded β clamp at ≥10-fold higher than chromosomally expressed levels impedes growth by interfering with DNA replication. A mutant clamp (βE202K bearing a glutamic acid-to-lysine substitution at residue 202) binds to DNA polymerase III (Pol III) with higher affinity than the wild-type clamp, suggesting that its failure to impede growth is independent of its ability to sequester Pol III away from the replication fork. Our results demonstrate that the dnaNE202K strain underinitiates DNA replication due to insufficient levels of DnaA-ATP and expresses several DnaA-regulated genes at altered levels, including nrdAB, that encode the class 1a ribonucleotide reductase (RNR). Elevated expression of nrdAB was dependent on hda function. As the β clamp-Hda complex regulates the activity of DnaA by stimulating its intrinsic ATPase activity, this finding suggests that the dnaNE202K allele supports an elevated level of Hda activity in vivo compared with the wild-type strain. In contrast, using an in vitro assay reconstituted with purified components the βE202K and wild-type clamp proteins supported comparable levels of Hda activity. Nevertheless, co-overexpression of the nrdAB-encoded RNR relieved the growth defect caused by elevated levels of the β clamp. These results support a model in which increased cellular levels of DNA precursors relieve the ability of elevated β clamp levels to impede growth and suggest either that multiple effects stemming from the dnaNE202K mutation contribute to elevated nrdAB levels or that Hda plays a noncatalytic role in regulating DnaA-ATP by sequestering it to reduce its availability. IMPORTANCE DnaA bound to ATP acts in initiation of DNA replication and regulates the expression of several genes whose products act in DNA metabolism. The state of the ATP bound to DnaA is regulated in part by the β clamp-Hda complex. The dnaNE202K allele was identified by virtue of its inability to impede growth when expressed ≥10-fold higher than chromosomally expressed levels. While the dnaNE202K strain exhibits several phenotypes consistent with heightened Hda activity, the wild-type and βE202K clamp proteins support equivalent levels of Hda activity in vitro. Taken together, these results suggest that βE202K-Hda plays a noncatalytic role in regulating DnaA-ATP. This, as well as alternative models, is discussed.
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Menikpurage IP, Woo K, Mera PE. Transcriptional Activity of the Bacterial Replication Initiator DnaA. Front Microbiol 2021; 12:662317. [PMID: 34140937 PMCID: PMC8203912 DOI: 10.3389/fmicb.2021.662317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
In bacteria, DnaA is the most conserved DNA replication initiator protein. DnaA is a DNA binding protein that is part of the AAA+ ATPase family. In addition to initiating chromosome replication, DnaA can also function as a transcription factor either as an activator or repressor. The first gene identified to be regulated by DnaA at the transcriptional levels was dnaA. DnaA has been shown to regulate genes involved in a variety of cellular events including those that trigger sporulation, DNA repair, and cell cycle regulation. DnaA's dual functions (replication initiator and transcription factor) is a potential mechanism for DnaA to temporally coordinate diverse cellular events with the onset of chromosome replication. This strategy of using chromosome replication initiator proteins as regulators of gene expression has also been observed in archaea and eukaryotes. In this mini review, we focus on our current understanding of DnaA's transcriptional activity in various bacterial species.
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Affiliation(s)
- Inoka P Menikpurage
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Kristin Woo
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Paola E Mera
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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The Escherichia coli QseB/QseC signaling is required for correct timing of replication initiation and cell motility. Gene 2020; 773:145374. [PMID: 33359126 DOI: 10.1016/j.gene.2020.145374] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/05/2020] [Accepted: 12/15/2020] [Indexed: 12/25/2022]
Abstract
The Escherichia coli QseB/QseC signaling regulates expressions of more than 50 genes encoding flagellar proteins and proteins associated with virulence. Here we found that absence of the QseB/QseC signaling led to an early initiation of chromosomal replication and higher concentration of DnaA which is initiator for replication. The upstream region of dnaA promoter contains three potential QseB binding sites and absence of these binding sites increased transcription of the dnaA gene in wild-type cells but not in the cells lacking the qseB/qseC genes, showing that the QseB/QseC signaling regulates dnaA expression through the QseB binding sites. Also increased cell motility but neither cell size nor growth rate in ΔqseBC and ΔqseB cells was observed and these effects were reversed by ectopic expression of QseBC. Further, it was found that QseB interacted with the DnaK chaperone and FtsZ cell division protein in vivo, and absence of DnaK or partial inactivation of FtsZ decreased cell motility. Thus, we conclude that the QseB/QseC signaling modulates timing of replication initiation by regulating expression of DnaA, coordinates cell motility with cell division through interacting with the DnaK and FtsZ protein.
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Toyotake Y, Nishiyama M, Yokoyama F, Ogawa T, Kawamoto J, Kurihara T. A Novel Lysophosphatidic Acid Acyltransferase of Escherichia coli Produces Membrane Phospholipids with a cis-vaccenoyl Group and Is Related to Flagellar Formation. Biomolecules 2020; 10:E745. [PMID: 32403425 PMCID: PMC7277886 DOI: 10.3390/biom10050745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/02/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023] Open
Abstract
Lysophosphatidic acid acyltransferase (LPAAT) introduces fatty acyl groups into the sn-2 position of membrane phospholipids (PLs). Various bacteria produce multiple LPAATs, whereas it is believed that Escherichia coli produces only one essential LPAAT homolog, PlsC-the deletion of which is lethal. However, we found that E. coli possesses another LPAAT homolog named YihG. Here, we show that overexpression of YihG in E. coli carrying a temperature-sensitive mutation in plsC allowed its growth at non-permissive temperatures. Analysis of the fatty acyl composition of PLs from the yihG-deletion mutant (∆yihG) revealed that endogenous YihG introduces the cis-vaccenoyl group into the sn-2 position of PLs. Loss of YihG did not affect cell growth or morphology, but ∆yihG cells swam well in liquid medium in contrast to wild-type cells. Immunoblot analysis showed that FliC was highly expressed in ∆yihG cells, and this phenotype was suppressed by expression of recombinant YihG in ∆yihG cells. Transmission electron microscopy confirmed that the flagellar structure was observed only in ∆yihG cells. These results suggest that YihG has specific functions related to flagellar formation through modulation of the fatty acyl composition of membrane PLs.
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Affiliation(s)
- Yosuke Toyotake
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Masayoshi Nishiyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Fumiaki Yokoyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Takuya Ogawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
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Gou Y, Liu W, Wang JJ, Tan L, Hong B, Guo L, Liu H, Pan Y, Zhao Y. CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli. Can J Microbiol 2019; 65:691-702. [DOI: 10.1139/cjm-2019-0100] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.
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Affiliation(s)
- Yi Gou
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
| | - Weiqi Liu
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
| | - Jing Jing Wang
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
| | - Ling Tan
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
| | - Bin Hong
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
| | - Linxia Guo
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
| | - Haiquan Liu
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
- Engineering Research Center of Food Thermal-Processing Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Yingjie Pan
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
| | - Yong Zhao
- College of Food Science & Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
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Huang H, Song CC, Yang ZL, Dong Y, Hu YZ, Gao F. Identification of the Replication Origins from Cyanothece ATCC 51142 and Their Interactions with the DnaA Protein: From In Silico to In Vitro Studies. Front Microbiol 2015; 6:1370. [PMID: 26696980 PMCID: PMC4674748 DOI: 10.3389/fmicb.2015.01370] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022] Open
Abstract
Based on the complete genome of Cyanothece ATCC 51142, the oriCs of both the circular and linear chromosomes in Cyanothece ATCC 51142 have been predicted by utilizing a web-based system Ori-Finder. Here, we provide experimental support for the results of Ori-Finder to identify the replication origins of Cyanothece ATCC 51142 and their interactions with the initiator protein, DnaA. The two replication origins are composed of three characteristically arranged DnaA boxes and an AT-rich stretch, and the oriC in the circular chromosome is followed by the dnaN gene. The dnaA gene is located downstream of the origin of the circular chromosome and it expresses a typical DnaA protein that is divided into four domains (I, II, III, IV), as with other members of the DnaA protein family. We purify DnaA (IV) and characterize the interaction of the purified protein with the replication origins, so as to offer experimental support for the prediction. The results of the electrophoretic mobility shift assay and DNase I footprint assay demonstrate that the C-terminal domain of the DnaA protein from Cyanothece ATCC 51142 specifically binds the oriCs of both the circular and linear chromosomes, and the DNase I footprint assay demonstrates that DnaA (IV) exhibits hypersensitive affinity with DnaA boxes in both oriCs.
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Affiliation(s)
- He Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Cheng-Cheng Song
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Zhi-Liang Yang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Yan Dong
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Yao-Zhong Hu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Feng Gao
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China ; Department of Physics, Tianjin University Tianjin, China
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Bell SP, Kaguni JM. Helicase loading at chromosomal origins of replication. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a010124. [PMID: 23613349 DOI: 10.1101/cshperspect.a010124] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Loading of the replicative DNA helicase at origins of replication is of central importance in DNA replication. As the first of the replication fork proteins assemble at chromosomal origins of replication, the loaded helicase is required for the recruitment of the rest of the replication machinery. In this work, we review the current knowledge of helicase loading at Escherichia coli and eukaryotic origins of replication. In each case, this process requires both an origin recognition protein as well as one or more additional proteins. Comparison of these events shows intriguing similarities that suggest a similar underlying mechanism, as well as critical differences that likely reflect the distinct processes that regulate helicase loading in bacterial and eukaryotic cells.
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Affiliation(s)
- Stephen P Bell
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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10
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Tsodikov OV, Biswas T. Structural and thermodynamic signatures of DNA recognition by Mycobacterium tuberculosis DnaA. J Mol Biol 2011; 410:461-76. [PMID: 21620858 DOI: 10.1016/j.jmb.2011.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 04/27/2011] [Accepted: 05/05/2011] [Indexed: 10/24/2022]
Abstract
An essential protein, DnaA, binds to 9-bp DNA sites within the origin of replication oriC. These binding events are prerequisite to forming an enigmatic nucleoprotein scaffold that initiates replication. The number, sequences, positions, and orientations of these short DNA sites, or DnaA boxes, within the oriCs of different bacteria vary considerably. To investigate features of DnaA boxes that are important for binding Mycobacterium tuberculosis DnaA (MtDnaA), we have determined the crystal structures of the DNA binding domain (DBD) of MtDnaA bound to a cognate MtDnaA-box (at 2.0 Å resolution) and to a consensus Escherichia coli DnaA-box (at 2.3 Å). These structures, complemented by calorimetric equilibrium binding studies of MtDnaA DBD in a series of DnaA-box variants, reveal the main determinants of DNA recognition and establish the [T/C][T/A][G/A]TCCACA sequence as a high-affinity MtDnaA-box. Bioinformatic and calorimetric analyses indicate that DnaA-box sequences in mycobacterial oriCs generally differ from the optimal binding sequence. This sequence variation occurs commonly at the first 2 bp, making an in vivo mycobacterial DnaA-box effectively a 7-mer and not a 9-mer. We demonstrate that the decrease in the affinity of these MtDnaA-box variants for MtDnaA DBD relative to that of the highest-affinity box TTGTCCACA is less than 10-fold. The understanding of DnaA-box recognition by MtDnaA and E. coli DnaA enables one to map DnaA-box sequences in the genomes of M. tuberculosis and other eubacteria.
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Affiliation(s)
- Oleg V Tsodikov
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA.
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Zhou Y, Chen WL, Wang L, Zhang CC. Identification of the oriC region and its influence on heterocyst development in the filamentous cyanobacterium Anabaena sp. strain PCC 7120. MICROBIOLOGY-SGM 2011; 157:1910-1919. [PMID: 21493684 DOI: 10.1099/mic.0.047241-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Anabaena sp. strain PCC 7120 (Anabaena PCC 7120) is a filamentous, nitrogen-fixing cyanobacterium. Upon deprivation of combined nitrogen, about 5-10 % of the cells become heterocysts, i.e. cells devoted to N(2) fixation. Heterocysts are intercalated among vegetative cells and distributed in a semi-regular pattern, and adjacent heterocysts are rarely observed. Previously, we showed that the cell cycle could play a regulatory function during heterocyst development, although the mechanism involved remains unknown. As a further step to understand this phenomenon, we identified the oriC region for chromosomal DNA replication, located between dnaA and dnaN. The oriC region of Anabaena PCC 7120 was able to support the self-replication of a plasmid in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Surprisingly, integration of the oriC region into the chromosome of Anabaena PCC 7120 through homologous recombination led to much slower cell growth in the absence of a combined-nitrogen source and to multiple contiguous proheterocysts after prolonged incubation. Real-time RT-PCR showed that expression of two heterocyst-related genes, hetR and hetN, was altered in these strains: hetR expression remained high 48 h after induction, and hetN increased to high levels after induction for 12 h. These results suggest that the balance between oriC and DnaA could be important for heterocyst development.
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Affiliation(s)
- Yin Zhou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Wen-Li Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Li Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Cheng-Cai Zhang
- Aix-Marseille Université and Laboratoire de Chimie Bactérienne, CNRS-UPR9043, 31, chemin Joseph Aiguier, 13402 Marseille cedex 20, France
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12
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Jenal U, Stephens C, Shapiro L. Regulation of asymmetry and polarity during the Caulobacter cell cycle. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 71:1-39. [PMID: 8644489 DOI: 10.1002/9780470123171.ch1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- U Jenal
- Department of Developmental Biology, Beckman Center for Molecular and Genetic Medicine, Stanford University School of Medicine, Stanford University, California 94305, USA
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13
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Prüss BM, Besemann C, Denton A, Wolfe AJ. A complex transcription network controls the early stages of biofilm development by Escherichia coli. J Bacteriol 2006; 188:3731-9. [PMID: 16707665 PMCID: PMC1482888 DOI: 10.1128/jb.01780-05] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Birgit M Prüss
- Department of Veterinary and Microbiological Sciences, North Dakota State University, 1523 Centennial Blvd., Fargo, ND 58105, USA.
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Stafford GP, Ogi T, Hughes C. Binding and transcriptional activation of non-flagellar genes by the Escherichia coli flagellar master regulator FlhD2C2. MICROBIOLOGY-SGM 2005; 151:1779-1788. [PMID: 15941987 PMCID: PMC2528288 DOI: 10.1099/mic.0.27879-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The gene hierarchy directing biogenesis of peritrichous flagella on the surface of Escherichia coli and other enterobacteria is controlled by the heterotetrameric master transcriptional regulator FlhD(2)C(2). To assess the extent to which FlhD(2)C(2) directly activates promoters of a wider regulon, a computational screen of the E. coli genome was used to search for gene-proximal DNA sequences similar to the 42-44 bp inverted repeat FlhD(2)C(2) binding consensus. This identified the binding sequences upstream of all eight flagella class II operons, and also putative novel FlhD(2)C(2) binding sites in the promoter regions of 39 non-flagellar genes. Nine representative non-flagellar promoter regions were all bound in vitro by active reconstituted FlhD(2)C(2) over the K(D) range 38-356 nM, and of the nine corresponding chromosomal promoter-lacZ fusions, those of the four genes b1904, b2446, wzz(fepE) and gltI showed up to 50-fold dependence on FlhD(2)C(2) in vivo. In comparison, four representative flagella class II promoters bound FlhD(2)C(2) in the K(D) range 12-43 nM and were upregulated in vivo 30- to 990-fold. The FlhD(2)C(2)-binding sites of the four regulated non-flagellar genes overlap by 1 or 2 bp the predicted -35 motif of the FlhD(2)C(2)-activated sigma(70) promoters, as is the case with FlhD(2)C(2)-dependent class II flagellar promoters. The data indicate a wider FlhD(2)C(2) regulon, in which non-flagellar genes are bound and activated directly, albeit less strongly, by the same mechanism as that regulating the flagella gene hierarchy.
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Affiliation(s)
- Graham P. Stafford
- University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Tomoo Ogi
- Genome Damage and Stability Centre, University of Sussex, Science Park Road, Falmer, Brighton BN1 9QG, UK
| | - Colin Hughes
- University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, UK
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15
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Affiliation(s)
- Walter Messer
- Max-Planck-Institute for Molecular Genitics, D-14195 Berlin, Germany
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16
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Chilcott GS, Hughes KT. Coupling of flagellar gene expression to flagellar assembly in Salmonella enterica serovar typhimurium and Escherichia coli. Microbiol Mol Biol Rev 2000; 64:694-708. [PMID: 11104815 PMCID: PMC99010 DOI: 10.1128/mmbr.64.4.694-708.2000] [Citation(s) in RCA: 494] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
How do organisms assess the degree of completion of a large structure, especially an extracellular structure such as a flagellum? Bacteria can do this. Mutants that lack key components needed early in assembly fail to express proteins that would normally be added at later assembly stages. In some cases, the regulatory circuitry is able to sense completion of structures beyond the cell surface, such as completion of the external hook structure. In Salmonella and Escherichia coli, regulation occurs at both transcriptional and posttranscriptional levels. One transcriptional regulatory mechanism involves a regulatory protein, FlgM, that escapes from the cell (and thus can no longer act) through a complete flagellum and is held inside when the structure has not reached a later stage of completion. FlgM prevents late flagellar gene transcription by binding the flagellum-specific transcription factor sigma(28). FlgM is itself regulated in response to the assembly of an incomplete flagellum known as the hook-basal body intermediate structure. Upon completion of the hook-basal body structure, FlgM is exported through this structure out of the cell. Inhibition of sigma(28)-dependent transcription is relieved, and genes required for the later assembly stages are expressed, allowing completion of the flagellar organelle. Distinct posttranscriptional regulatory mechanisms occur in response to assembly of the flagellar type III secretion apparatus and of ring structures in the peptidoglycan and lipopolysaccharide layers. The entire flagellar regulatory pathway is regulated in response to environmental cues. Cell cycle control and flagellar development are codependent. We discuss how all these levels of regulation ensure efficient assembly of the flagellum in response to environmental stimuli.
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Affiliation(s)
- G S Chilcott
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA
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17
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Majka J, Jakimowicz D, Messer W, Schrempf H, Lisowski M, Zakrzewska-Czerwińska J. Interactions of the Streptomyces lividans initiator protein DnaA with its target. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 260:325-35. [PMID: 10095766 DOI: 10.1046/j.1432-1327.1999.00168.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Streptomyces lividans DnaA protein (73 kDa) consists, like other bacterial DnaA proteins, of four domains; it binds to 19 DnaA boxes in the complex oriC region. The S. lividans DnaA protein differs from others in that it contains an additional stretch of 120 predominantly acidic amino acids within domain II. Interactions between the DnaA protein and the two DnaA boxes derived from the promoter region of the S. lividans dnaA gene were analysed in vitro using three independent methods: Dnase-I-footprinting experiments, mobility-shift assay and surface plasmon resonance (SPR). The Dnase-I-footprinting analysis showed that the wild-type DnaA protein binds to both DnaA boxes. Thus, as in Escherichia coli and Bacillus subtilis, the S. lividans dnaA gene may be autoregulated. SPR analysis showed that the affinity of the DnaA protein for a DNA fragment containing both DnaA boxes from the dnaA promoter region (KD = 1.25 nM) is 10 times higher than its affinity for the single 'strong' DnaA box (KD = 12.0 nM). The mobility-shift assay suggests the presence of at least two classes of complex containing different numbers of bound DnaA molecules. The above data reveal that the DnaA protein binds to the two DnaA boxes in a cooperative manner. To deduce structural features of the Streptomyces domain II of DnaA protein, the amino acid DnaA sequences of three Streptomyces species were compared. However, according to the secondary structure prediction, Streptomyces domain II does not contain any common relevant secondary structural element(s). It can be assumed that domain II of DnaA protein can play a role as a flexible protein spacer between the N-terminal domain I and the highly conserved C-terminal part of DnaA protein containing ATP-binding domain III and DNA-binding domain IV.
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Affiliation(s)
- J Majka
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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18
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DiRusso CC, Black PN, Weimar JD. Molecular inroads into the regulation and metabolism of fatty acids, lessons from bacteria. Prog Lipid Res 1999; 38:129-97. [PMID: 10396600 DOI: 10.1016/s0163-7827(98)00022-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- C C DiRusso
- Department of Biochemistry and Molecular Biology, Albany Medical College, New York, USA.
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19
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Jacobson BA, Fuchs JA. A 45 bp inverted repeat is required for cell cycle regulation of the Escherichia coli nrd operon. Mol Microbiol 1998; 28:1307-14. [PMID: 9680218 DOI: 10.1046/j.1365-2958.1998.00896.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Expression of beta-galactosidase from a nrd-lacZ fusion was used to determine the role in nrd regulation of an inverted sequence upstream of the promoter. Removal or replacement of a 45bp inverted repeat with an altered sequence including a 48bp perfect inverted repeat resulted in a mutant phenotype that was low in nrd expression in an exponentially growing culture and that did not increase during DNA synthesis inhibition. Changing the 22 bp in the upstream half of the inverted repeat resulted in the same phenotype, whereas changing the 22 bp in the downstream half of the inverted repeat decreased nrd expression to a lesser extent in an exponentially growing culture and had only a smaller effect on nrd expression during DNA synthesis inhibition. As other mutants with the phenotype of the upstream inverted repeat mutant were found to lack cell cycle regulation, expression of nrd-lac mRNA produced from a plasmid with this mutation in the nrd-lacZ fusion gene was compared with nrd mRNA produced from the chromosomal nrd gene in a synchronized culture. The results indicated that the upstream half of the nrd inverted repeat contains a cis-acting element essential for nrd cell cycle regulation.
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Affiliation(s)
- B A Jacobson
- Department of Biochemistry, University of Minnesota, St Paul 55108, USA
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20
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Abstract
Regulation of nrd expression in Escherichia coli by cis-acting elements was found to be more complex than previously reported. At least five upstream sites appear to positively regulate nrd expression including a Fis binding site, a DnaA binding site, an AT-rich region, an inverted repeat and a 10 bp site between the AT-rich region and the inverted repeat. Double mutants defective in these sites indicate that all sites tested act independently when regulating nrd expression. As the decrease in nrd expression in exponentially growing cultures paralleled the decrease observed in DNA synthesis-inhibited cultures for all single and double mutants, we concluded that nrd is regulated by the same mechanism in these physiological states. As mutants unable to induce nrd expression during inhibition of DNA synthesis also fail to exhibit cell cycle-regulated nrd expression, we conclude that cell cycle nrd regulation is controlled by these same sites. Site-directed mutagenesis was used to show that the absence of an increase in nrd expression during DNA inhibition previously observed for deletion of the AT-rich region results from deletion of both the Fis binding site and the AT-rich region.
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Affiliation(s)
- B A Jacobson
- Department of Biochemistry, University of Minnesota, St. Paul 55108, USA
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21
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Suzuki E, Kondo T, Makise M, Mima S, Sakamoto K, Tsuchiya T, Mizushima T. Alteration in the contents of unsaturated fatty acids in dnaA mutants of Escherichia coli. Mol Microbiol 1998; 28:95-102. [PMID: 9593299 DOI: 10.1046/j.1365-2958.1998.00777.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
DnaA protein, the initiator of chromosomal DNA replication in Escherichia coli, has a high affinity for acidic phospholipids containing unsaturated fatty acids. We have examined here the fatty acid composition of phospholipids in dnaA mutants. A temperature-sensitive dnaA46 mutant showed a lower level of unsaturation of fatty acids (ratio of unsaturated to saturated fatty acids) at 42 degrees C (non-permissive temperature) and at 37 degrees C (semi-permissive temperature), but not at 28 degrees C (permissive temperature), compared with the wild-type strain. Plasmid complementation analysis revealed that the dnaA46 mutation is responsible for the phenotype. Other temperature-sensitive dnaA mutants showed similar results. On the other hand, a cold-sensitive dnaAcos mutant, in which over-initiation of DNA replication occurs at low temperature (28 degrees C), showed a higher level of unsaturation of fatty acids at 28 degrees C. Based on these observations, we discuss the role of phospholipids in the regulation of the activity of DnaA protein.
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Affiliation(s)
- E Suzuki
- Preclinical Development Laboratories, Research and Development Division, Nippon Hoechst Marion Roussel, Ltd, Minamidai, Kawagoe, Japan
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22
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Mizushima T, Yokoyama K, Mima S, Tsuchiya T, Sekimizu K. Inhibition of thymidine transport in dnaA mutants of Escherichia coli. J Biol Chem 1997; 272:21195-200. [PMID: 9261126 DOI: 10.1074/jbc.272.34.21195] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
DnaA protein is the initiator of chromosomal DNA replication in Escherichia coli. We report here our evidence that thymidine transport across cytoplasmic membranes in temperature-sensitive dnaA mutants is greatly decreased at a permissive temperature for growth of the mutants. Complementation analysis with a plasmid containing the wild type dnaA gene and P1 phage-mediated transduction confirmed that mutations in the dnaA gene were responsible for the phenotype. A low level of nucleoside transport in the dnaA mutant was specific for thymidine; transport activities for other nucleosides were much the same as those in wild type cells. Membrane vesicles prepared from the dnaA mutant showed much the same activity of thymidine transport as did those from the wild type cells. No significant difference in the activity of thymidine kinase, which is known to facilitate thymidine transport, was seen between the mutant and the wild type cells. An increase in the pool of dTTP, a negative regulator for thymidine kinase, was observed in the dnaA mutant. Based on these observations, we suggest that inhibition of thymidine transport in dnaA mutants is caused by increases in the dTTP pool.
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Affiliation(s)
- T Mizushima
- Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-82, Japan
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23
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Nishida S, Mizushima T, Miki T, Sekimizu K. Immotile phenotype of an Escherichia coli mutant lacking the histone-like protein HU. FEMS Microbiol Lett 1997; 150:297-301. [PMID: 9170274 DOI: 10.1111/j.1574-6968.1997.tb10384.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The histone-like protein HU in Escherichia coli are encoded by the hupA and hupB genes. A hupA-hupB double deletion mutant has now been shown to express an immotile phenotype. The motility of hupA or hupB single mutants was similar to that of wild-type cells. SDS-polyacrylamide gel electrophoresis revealed that the amount of flagellin in the hupA-hupB double deletion mutant was markedly reduced compared with the wild-type strain suggesting that the immotile phenotype of the double deletion mutant is caused by a loss of flagella.
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Affiliation(s)
- S Nishida
- Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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24
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Mizushima T, Matsuo M, Sekimizu K. Induction of DnaK and GroEL heat shock proteins by fluoroquinolones in Escherichia coli. Antimicrob Agents Chemother 1997; 41:193-5. [PMID: 8980780 PMCID: PMC163685 DOI: 10.1128/aac.41.1.193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Various fluoroquinolones (norfloxacin, enoxacin, ofloxacin, levofloxacin, and sparfloxacin) induce DnaK and GroEL heat shock proteins in Escherichia coli. The induction is transient, consistent with the kinetics of cellular DNA relaxation. The concentrations of fluoroquinolones required for induction are similar to those required for DNA relaxation and much higher than those required for cell death.
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Affiliation(s)
- T Mizushima
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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25
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Wegrzyn G, Wegrzyn A, Pankiewicz A, Taylor K. Allele specificity of the Escherichia coli dnaA gene function in the replication of plasmids derived from phage lambda. MOLECULAR & GENERAL GENETICS : MGG 1996; 252:580-6. [PMID: 8914519 DOI: 10.1007/bf02172404] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We demonstrate a variation in the effects of seven alleles of the Escherichia coli dnaA gene, which cause temperature sensitivity of initiation of chromosomal replication, on the replication of lambda phage-derived plasmids at 30 degrees C. These mutants showed no allele specificity of dnaA function in replication of either of two lambda pi plasmids studied. On the other hand, the inability of the lambda P+ plasmid to replicate in dnaA508, 46 and 204 cells, in dnaB (groP A15) or in cells that are temperature sensitive for the chaperone genes dnaK756, dnaJ259 and grpE280 at 30 degrees C was suppressible by a single pi mutatation. This suggests that it is a common property of the pi protein, probably its weaker interaction with DnaB helicase, that is responsible for the suppression. One can also conclude that the DnaA-regulated transcriptional activation of ori lambda acts at the step, in which all these gene products cooperate, i.e. during preprimosome loading and chaperone-mediated release of DnaB from P protein inhibition.
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Affiliation(s)
- G Wegrzyn
- University of Gdańsk, Department of Molecular Biology, Poland
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26
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Matsuo M, Ohtsuka Y, Kataoka K, Mizushima T, Sekimizu K. Transient relaxation of plasmid DNA in Escherichia coli by fluoroquinolones. J Pharm Pharmacol 1996; 48:985-7. [PMID: 8910869 DOI: 10.1111/j.2042-7158.1996.tb06018.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We examined the influence of fluoroquinolones (norfloxacin, enoxacin, ofloxacin, levofloxacin, and sparfloxacin) on DNA supercoiling of plasmids in Escherichia coli cells by analysis with agarose gel electrophoresis in the presence of chloroquine. All the fluoroquinolones tested immediately induced DNA relaxation. The relaxed DNA was re-supercoiled, and the process was sensitive to chloramphenicol, suggesting that newly synthesized proteins participate in the reaction. The concentrations of fluoroquinolones required for DNA relaxation were much higher than those required for cell killing. The bactericidal effect of fluoroquinolones is apparently related to mechanisms other than DNA relaxation.
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Affiliation(s)
- M Matsuo
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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27
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Mizushima T, Koyanagi R, Suzuki E, Tomura A, Kutsukake K, Miki T, Sekimizu K. Control by phosphatidylglycerol of expression of the flhD gene in Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1245:397-401. [PMID: 8541318 DOI: 10.1016/0304-4165(95)00114-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We reported elsewhere that mutation in the pgsA gene, responsible for the synthesis of phosphatidylglycerol, repressed the synthesis of flagellin and caused the loss of motility of Escherichia coli (Tomura et al., FEBS Letters 329, 287-290, 1993). We now describe evidence for a decrease in promoter activity of the flhD gene, a master gene for flagellum synthesis, in the pgsA3 mutant. We constructed a plasmid with a promoter region of the flhD gene connected with the structure region of the lacZ gene. The activity of beta-galactosidase in the extract prepared from the pgsA3 mutant harboring the fusion plasmid was 30% of that in the wild type cells. This result means that phosphatidylglycerol is likely to be required for the initiation of transcription of the flhD gene. We also found that the motility-less phenotype of the mutant was partially suppressed by elevating incubation temperature. This suppression is caused by restoration of transcription of the flhD gene by high temperature. As the content of phosphatidylglycerol did not increase by elevating incubation temperature, we proposed that this suppression is caused by alternation of a physical structure of phospholipid bilayers in cytoplasmic membranes.
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Affiliation(s)
- T Mizushima
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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