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Olszewski P, Szambowska A, Barałska S, Narajczyk M, Węgrzyn G, Glinkowska M. A dual promoter system regulating λ DNA replication initiation. Nucleic Acids Res 2014; 42:4450-62. [PMID: 24500197 PMCID: PMC3985674 DOI: 10.1093/nar/gku103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Transcription and DNA replication are tightly regulated to ensure coordination of gene expression with growth conditions and faithful transmission of genetic material to progeny. A large body of evidence has accumulated, indicating that encounters between protein machineries carrying out DNA and RNA synthesis occur in vivo and may have important regulatory consequences. This feature may be exacerbated in the case of compact genomes, like the one of bacteriophage λ, used in our study. Transcription that starts at the rightward pR promoter and proceeds through the λ origin of replication and downstream of it was proven to stimulate the initiation of λ DNA replication. Here, we demonstrate that the activity of a convergently oriented pO promoter decreases the efficiency of transcription starting from pR. Our results show, however, that a lack of the functional pO promoter negatively influences λ phage and λ-derived plasmid replication. We present data, suggesting that this effect is evoked by the enhanced level of the pR-driven transcription, occurring in the presence of the defective pO, which may result in the impeded formation of the replication initiation complex. Our data suggest that the cross talk between the two promoters regulates λ DNA replication and coordinates transcription and replication processes.
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Affiliation(s)
- Paweł Olszewski
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland, Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Wita Stwosza 59, 80-308 Gdańsk, Poland and Laboratory of Electron Microscopy, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland
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2
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A role for accessory genes rI.-1 and rI.1 in the regulation of lysis inhibition by bacteriophage T4. Virus Genes 2010; 41:459-68. [PMID: 20945083 PMCID: PMC2962797 DOI: 10.1007/s11262-010-0532-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Accepted: 09/17/2010] [Indexed: 11/29/2022]
Abstract
Lysis inhibition (LIN) is a known feature of the T-even family of bacteriophages. Despite its historical role in the development of modern molecular genetics, many aspects of this phenomenon remain mostly unexplained. The key element of LIN is an interaction between two phage-encoded proteins, the T holin and the RI antiholin. This interaction is stabilized by RIII. In this report, we demonstrate the results of genetic experiments which suggest a synergistic action of two accessory proteins of bacteriophage T4, RI.-1, and RI.1 with RIII in the regulation of LIN.
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Narajczyk M, Barańska S, Szambowska A, Glinkowska M, Węgrzyn A, Węgrzyn G. Modulation of lambda plasmid and phage DNA replication by Escherichia coli SeqA protein. MICROBIOLOGY-SGM 2007; 153:1653-1663. [PMID: 17464080 DOI: 10.1099/mic.0.2006/005546-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
SeqA protein, a main negative regulator of the replication initiation of the Escherichia coli chromosome, also has several other functions which are still poorly understood. It was demonstrated previously that in seqA mutants the copy number of another replicon, the lambda plasmid, is decreased, and that the activity of the lambda p(R) promoter (whose function is required for stimulation of ori lambda) is lower than that in the wild-type host. Here, SeqA-mediated regulation of lambda phage and plasmid replicons was investigated in more detail. No significant influence of SeqA on ori lambda-dependent DNA replication in vitro was observed, indicating that a direct regulation of lambda DNA replication by this protein is unlikely. On the other hand, density-shift experiments, in which the fate of labelled lambda DNA was monitored after phage infection of host cells, strongly suggested the early appearance of sigma replication intermediates and preferential rolling-circle replication of phage DNA in seqA mutants. The directionality of lambda plasmid replication in such mutants was, however, only slightly affected. The stability of the heritable lambda replication complex was decreased in the seqA mutant relative to the wild-type host, but a stable fraction of the lambda O protein was easily detectable, indicating that such a heritable complex can function in the mutant. To investigate the influence of seqA gene function on heritable complex- and transcription-dependent lambda DNA replication, the efficiency of lambda plasmid replication in amino acid-starved relA seqA mutants was measured. Under these conditions, seqA dysfunction resulted in impairment of lambda plasmid replication. These results indicate that unlike oriC, SeqA modulates lambda DNA replication indirectly, most probably by influencing the stability of the lambda replication complex and the transcriptional activation of ori lambda.
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Affiliation(s)
- Magdalena Narajczyk
- Department of Molecular Biology, University of Gdańsk, 80-822 Gdańsk, Poland
| | - Sylwia Barańska
- Department of Molecular Biology, University of Gdańsk, 80-822 Gdańsk, Poland
| | - Anna Szambowska
- Department of Molecular Biology, University of Gdańsk, 80-822 Gdańsk, Poland
| | - Monika Glinkowska
- Department of Molecular Biology, University of Gdańsk, 80-822 Gdańsk, Poland
| | - Alicja Węgrzyn
- Laboratory of Molecular Biology (affiliated with University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 80-822 Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, 80-822 Gdańsk, Poland
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4
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Narajczyk M, Barańska S, Wegrzyn A, Wegrzyn G. Switch from theta to sigma replication of bacteriophage lambda DNA: factors involved in the process and a model for its regulation. Mol Genet Genomics 2007; 278:65-74. [PMID: 17377819 DOI: 10.1007/s00438-007-0228-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Accepted: 02/26/2007] [Indexed: 10/23/2022]
Abstract
Bacteriophage lambda genome is one of the classical model replicons in studies on the regulation of DNA replication. Moreover, since genes coding for Shiga toxins are located in genomes of lambdoid phages, understanding of mechanisms controlling lambda DNA replication may be of bio-medical importance. During lytic development of bacteriophage lambda, its genome is replicated according to the theta (circle-to-circle) mode early after infection, and then it is switched to the sigma (rolling circle) mode. Two mechanisms of regulation of this switch were proposed recently and both suggested a crucial role for directionality of lambda DNA replication. Whereas one hypothesis assumed transient impairment of ClpP/ClpX-mediated proteolysis of the lambdaO initiator protein, another suggested a crucial role for transcriptional activation of the orilambda region and factors involved in the control of the p (R) promoter activity. Here we demonstrate that mutations in clpP and clpX genes had little influence on both directionality of lambda DNA replication and appearance of sigma replication intermediates. On the other hand, regulators affecting activity of the p (R) promoter (responsible for initiation of transcription, which activates orilambda) directly or indirectly influenced directionality of lambda DNA replication to various extents. Therefore, we conclude that regulation of the efficiency of transcriptional activation of orilambda, rather than transient impairment of the lambdaO proteolysis, is responsible for the control of the switch from theta to sigma replication, and propose a model for this control.
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Affiliation(s)
- Magdalena Narajczyk
- Department of Molecular Biology, University of Gdańsk, Kładki 24, 80-822, Gdańsk, Poland
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Byrne M, Kropinski AM. The genome of the Pseudomonas aeruginosa generalized transducing bacteriophage F116. Gene 2005; 346:187-94. [PMID: 15716012 DOI: 10.1016/j.gene.2004.11.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Revised: 09/28/2004] [Accepted: 11/05/2004] [Indexed: 11/22/2022]
Abstract
F116 is a temperate, pilus-specific, generalized transducing phage belonging to the Podoviridae virus family. Its genome is linear, ds, TR, and CP DNA with a GC content of 63.2%. The 65 195-bp genome contains 70 putative ORFs, only 16 of which showed sequence similarity to Pseudomonas genomic or phage genes. While the current literature suggests that F116 is a non-integrating phage that maintains itself as a plasmid during the lysogenic life cycle, a putative int gene was identified. Of the phage structural genes, only the portal protein could be identified by homology. Analysis of F116 structural protein by one-dimensional SDS-PAGE revealed approximately 15 bands. MALDI-TOF MS analysis identified the gene encoding the major capsid protein. This protein appears to undergo posttranslational cleavage giving rise to a smaller capsid protein.
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Affiliation(s)
- Michaela Byrne
- Queen's University, Department of Microbiology and Immunology, Kingston, Ontario, Canada K7L 3N6
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Wegrzyn G, Wegrzyn A. Genetic switches during bacteriophage lambda development. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2005; 79:1-48. [PMID: 16096026 DOI: 10.1016/s0079-6603(04)79001-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Affiliation(s)
- Grzegorz Wegrzyn
- Department of Molecular Biology, University of Gdańsk, 80-822 Gdańsk, Poland
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7
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Słomińska M, Konopa G, Barańska S, Wegrzyn G, Wegrzyn A. Interplay between DnaA and SeqA proteins during regulation of bacteriophage lambda pR promoter activity. J Mol Biol 2003; 329:59-68. [PMID: 12742018 DOI: 10.1016/s0022-2836(03)00378-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DnaA and SeqA proteins are main regulators (positive and negative, respectively) of the chromosome replication in Escherichia coli. Nevertheless, both these replication regulators were found recently to be also transcription factors. Interestingly, both DnaA and SeqA control activity of the bacteriophage lambdap(R) promoter by binding downstream of the transcription start site, which is unusual among prokaryotic systems. Here we asked what are functional relationships between these two transcription regulators at one promoter region. Both in vivo and in vitro studies revealed that DnaA and SeqA can activate the p(R) promoter independently and separately rather than in co-operation, however, increased concentrations of one of these proteins negatively influenced the transcription stimulation mediated by the second regulator. This may suggest a competition between DnaA and SeqA for binding to the p(R) regulatory region. The physiological significance of this DnaA and SeqA-mediated regulation of p(R) is demonstrated by studies on lambda plasmid DNA replication in vivo.
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Affiliation(s)
- Monika Słomińska
- Department of Molecular Biology, University of Gdańsk, Klz.shtsls;adki 24, 80-822, Gdańsk, Poland
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8
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Farkasovská J, Godány A, Bukovská G, Timko J. An origin of DNA replication from streptomycete phage phi U1. Folia Microbiol (Praha) 2002; 46:483-7. [PMID: 11898336 DOI: 10.1007/bf02817990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A DNA fragment from phage phi U1 containing an origin of DNA replication was identified. This fragment, designated ori, was able to support the maintenance in Streptomyces lividans of a plasmid lacking a functional Gram-positive ori. The sequence of the minimal ori fragment was determined and analyzed. The minimal fragment conferring replication origin function contained a number of direct and inverted repeats. The absence of an open reading frame in this ori fragment indicates that host factors alone were sufficient to initiate replication at ori.
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Affiliation(s)
- J Farkasovská
- Institute of Molecular Biology, Slovak Academy of Sciences, 842 51 Bratislava, Slovakia
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9
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Glinkowska M, Konopa G, Węgrzyn A, Herman-Antosiewicz A, Weigel C, Seitz H, Messer W, Węgrzyn G. The double mechanism of incompatibility between lambda plasmids and Escherichia coli dnaA(ts) host cells. MICROBIOLOGY (READING, ENGLAND) 2001; 147:1923-1928. [PMID: 11429468 DOI: 10.1099/00221287-147-7-1923] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
For plasmids derived from bacteriophage lambda, the initiation of bidirectional DNA replication from orilambda depends on the stimulation of transcription from the p(R) promoter by the host replication initiator protein DnaA. Certain Escherichia coli dnaA(ts) mutants cannot be transformed by wild-type lambda plasmids even at the temperature permissive to cell growth. This plasmid-host incompatibility appeared to be due to inefficient stimulation of transcription from the p(R) promoter by the mutant DnaA protein. This paper shows that there is a second mechanism for the incompatibility between lambda plasmids and dnaA(ts) hosts, exemplified in this study by the dnaA46 mutant. This is based on the competition between the lambda P protein and the host DnaA and DnaC proteins for DnaB helicase. Both mechanisms must be operative for the incompatibility.
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Affiliation(s)
- Monika Glinkowska
- Department of Molecular Biology, University of Gdańsk, Kladki 24, 80-822 Gdańsk, Poland1
| | - Grażyna Konopa
- Department of Molecular Biology, University of Gdańsk, Kladki 24, 80-822 Gdańsk, Poland1
| | - Alicja Węgrzyn
- Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Polish Academy of Sciences, Kładki 24, 80-822 Gdańsk, Poland2
| | | | - Christoph Weigel
- Max-Planck-Institut für Molekulare Genetik, Ihnestrasse 73, D-14195 Berlin-Dahlem, Germany3
| | - Harald Seitz
- Max-Planck-Institut für Molekulare Genetik, Ihnestrasse 73, D-14195 Berlin-Dahlem, Germany3
| | - Walter Messer
- Max-Planck-Institut für Molekulare Genetik, Ihnestrasse 73, D-14195 Berlin-Dahlem, Germany3
| | - Grzegorz Węgrzyn
- Marine Biology Centre, Polish Academy of Sciences, Św. Wojciecha 5, 81-347 Gdynia, Poland4
- Department of Molecular Biology, University of Gdańsk, Kladki 24, 80-822 Gdańsk, Poland1
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10
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Slomińska M, Wegrzyn A, Konopa G, Skarstad K, Wegrzyn G. SeqA, the Escherichia coli origin sequestration protein, is also a specific transcription factor. Mol Microbiol 2001; 40:1371-9. [PMID: 11442835 DOI: 10.1046/j.1365-2958.2001.02480.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The SeqA protein is a negative regulator of initiation of DNA replication in the Escherichia coli chromosome. Here, we demonstrate that SeqA stimulates transcription from the bacteriophage lambda pR promoter both in vivo and in vitro. The activity of the lambda pL promoter was found not to be affected by this protein. SeqA-mediated stimulation of pR was dependent on the state of template methylation: transcription was activated on fully methylated and hemimethylated templates but not on an unmethylated template. Using electrophoretic mobility shift assay and electron microscopy, we demonstrated that SeqA interacts specifically with a pR promoter region located on both fully methylated and hemimethylated DNA molecules, but not on unmethylated DNA. The activity of SeqA was found to affect the initiation of lambda plasmid replication positively in vivo, probably via pR-dependent expression of lambda replication genes and transcriptional activation of ori lambda. We conclude that, apart from its function in the control of DNA replication, SeqA is also a specific transcription factor.
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Affiliation(s)
- M Slomińska
- Department of Molecular Biology, University of Gdańsk, Kladki 24, 80-822 Gdańsk, Poland
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11
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Barańska S, Gabig M, Węgrzyn A, Konopa G, Herman-Antosiewicz A, Hernandez P, Schvartzman JB, Helinski DR, Węgrzyn G. Regulation of the switch from early to late bacteriophage lambda DNA replication. MICROBIOLOGY (READING, ENGLAND) 2001; 147:535-547. [PMID: 11238961 DOI: 10.1099/00221287-147-3-535] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
There are two modes of bacteriophage lambda DNA replication following infection of its host, Escherichia coli. Early after infection, replication occurs according to the theta (theta or circle-to-circle) mode, and is later switched to the sigma (sigma or rolling-circle) mode. It is not known how this switch, occurring at a specific time in the infection cycle, is regulated. Here it is demonstrated that in wild-type cells the replication starting from orilambda proceeds both bidirectionally and unidirectionally, whereas in bacteria devoid of a functional DnaA protein, replication from orilambda is predominantly unidirectional. The regulation of directionality of replication from orilambda is mediated by positive control of lambda p(R) promoter activity by DnaA, since the mode of replication of an artificial lambda replicon bearing the p(tet) promoter instead of p(R) was found to be independent of DnaA function. These findings and results of density-shift experiments suggest that in dnaA mutants infected with lambda, phage DNA replication proceeds predominantly according to the unidirectional theta mechanism and is switched early after infection to the sigma mode. It is proposed that in wild-type E. coli cells infected with lambda, phage DNA replication proceeds according to a bidirectional theta mechanism early after infection due to efficient transcriptional activation of orilambda, stimulated by the host DnaA protein. After a few rounds of this type of replication, the resulting increased copy number of lambda genomic DNA may cause a depletion of free DnaA protein because of its interaction with the multiple DnaA-binding sites in lambda DNA. It is proposed that this may lead to inefficient transcriptional activation of orilambda resulting in unidirectional theta replication followed by sigma type replication.
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Affiliation(s)
- Sylwia Barańska
- Department of Molecular Biology, University of Gdańsk1 and Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences2, Kładki 24, 80-822 Gdańsk, Poland
| | - Magdalena Gabig
- Department of Molecular Biology, University of Gdańsk1 and Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences2, Kładki 24, 80-822 Gdańsk, Poland
| | - Alicja Węgrzyn
- Department of Molecular Biology, University of Gdańsk1 and Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences2, Kładki 24, 80-822 Gdańsk, Poland
| | - Grażyna Konopa
- Department of Molecular Biology, University of Gdańsk1 and Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences2, Kładki 24, 80-822 Gdańsk, Poland
| | - Anna Herman-Antosiewicz
- Department of Molecular Biology, University of Gdańsk1 and Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences2, Kładki 24, 80-822 Gdańsk, Poland
| | - Pablo Hernandez
- Departamento de Biologı́a Celular y del Desarrollo, Centro de Investigaciones Biológicas (CSIC), Velázquez 144, 28006 Madrid, Spain3
| | - Jorge B Schvartzman
- Departamento de Biologı́a Celular y del Desarrollo, Centro de Investigaciones Biológicas (CSIC), Velázquez 144, 28006 Madrid, Spain3
| | - Donald R Helinski
- Center for Molecular Genetics and Department of Biology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA4
| | - Grzegorz Węgrzyn
- Marine Biology Center, Polish Academy of Sciences, Św. Wojciecha 5, 81-347 Gdynia, Poland5
- Department of Molecular Biology, University of Gdańsk1 and Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences2, Kładki 24, 80-822 Gdańsk, Poland
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12
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Herman-Antosiewicz A, Wegrzyn G. Regulation of copy number and stability of phage lambda derived pTC lambda 1 plasmid in the light of the dimer/multimer catastrophe hypothesis. FEMS Microbiol Lett 1999; 176:489-93. [PMID: 10427732 DOI: 10.1111/j.1574-6968.1999.tb13702.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The dimer catastrophe hypothesis has been proposed previously to explain instability of multicopy plasmids whose partitioning is random, contrary to low copy number plasmids which are stably maintained and actively partitioned. Until now, this hypothesis has been investigated using multicopy ColE1 plasmids. However, for more detailed testing of the dimer/multimer catastrophe hypothesis, one should use a plasmid which can be maintained at either low or high copy number and still possesses the same mechanism of replication regulation. Here we used a modified lambda plasmid, pTC lambda 1. The advantage of this plasmid is that it can be maintained at different copy numbers depending on the concentration of an inducer which stimulates the initiation of plasmid replication. Results obtained with this plasmid in recombination proficient and deficient cells generally support the dimer/multimer catastrophe hypothesis, but also suggest some modification in the model.
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13
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Abstract
Amino acid starvation of bacterial cells leads to expression of the stringent (in wild-type strains) or relaxed (in relA mutants) response (also called the stringent or relaxed control, respectively). The stringent control is a pleiotropic response which changes drastically almost the entire cell physiology. Although starvation is a rule rather than an exception in natural environments of bacteria, and DNA replication is a fundamental cell process, until recently our knowledge about regulation of DNA replication in amino acid-starved cells has been unexpectedly poor. Within recent years the stringent control of DNA replication has been investigated mainly on plasmid models. Several plasmid replicons have been studied, including oriC plasmids, ColE1-like replicons, pSC101, F, R1, RK2, and R6K, and plasmids derived from bacteriophages lambda and P1. However, molecular models of replication regulation in amino acid-starved cells have been proposed to date only for lambda plasmids and ColE1-like replicons. Although further extensive studies are necessary in the understanding of molecular mechanisms of the stringent and relaxed control of replication of other plasmids, the results obtained to date (summarized and discussed in this review) show that studies on DNA replication in amino acid-starved cells may provide new insights into the regulatory mechanisms and lead to more general conclusions.
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Affiliation(s)
- G Wegrzyn
- Department of Molecular Biology, University of Gdańsk, Kladki 24, Gdańsk, 80-822,
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14
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Herman-Antosiewicz A, Wegrzyn A, Taylor K, Wegrzyn G. DnaA-mediated regulation of phage lambda-derived replicons in the absence of pR and Cro function. Virology 1998; 249:98-107. [PMID: 9740781 DOI: 10.1006/viro.1998.9319] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bacteriophage lambda-derived replicons can replicate in Escherichia coli cells as plasmids. In the control of replication of these plasmids, an important role was ascribed to the lambda Cro repressor autoregulatory loop. However, the oR/pR-cro-tR-cII' region could be replaced by the ptetA promoter under the control of the TetR repressor, producing plasmid pTClambda. Here, we demonstrate that stable maintenance of pTClambda depends on the host DnaA function because deletion of one of DnaA-binding sequences present in pTClambda resulted in a decrease in the plasmid (pTClambda) copy number and poor maintenance of pTClambda in E. coli. Moreover, in contrast to the replication of the wild-type lambda plasmid, previously found to be positively regulated by DnaA (acting on a relaxed DnaA box situated immediately downstream of the pR promoter), the replication of pTC plasmids (devoid of pR) was found to be negatively regulated by DnaA. Contrary to wild-type lambda plasmids, in cells harboring lambda cro[temperature-sensitive (ts)] or pTClambda (but not pTClambda) plasmid, the lambda replication complex was heat shock resistant; this complex, however, disassembled after inactivation of DnaA function. This disassembly was blocked by DNA gyrase inhibitors. According to our model outlined previously, we propose that the heat shock resistance of the replication complex of lambdacro- plasmids depends on the interaction of the DNA-bound DnaA protein with the DNA-bound lambda replication complex. The replication complex-DnaA-lambda DNA structure may be directly related to the role of DnaA as the Cro-replacing negative regulator of lambdacro- plasmid replication.
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Affiliation(s)
- A Herman-Antosiewicz
- Department of Molecular Biology, University of Gdañsk, Kladki 24, Gdañsk, 80-822, Poland
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15
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Gabig M, Obuchowski M, WeLgrzyn A, Szalewska-Palasz A, Thomas MS, WeLgrzyn G. Excess production of phage lambda delayed early proteins under conditions supporting high Escherichia coli growth rates. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 8):2217-2224. [PMID: 9720043 DOI: 10.1099/00221287-144-8-2217] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacteriophage lambda is unable to lysogenize Escherichia coli hosts harbouring the rpoA341 mutation due to a drastic reduction in transcription from CII-activated lysogenic promoters (pE, pI and paQ). In addition, the level of early transcripts involved in the lytic pathway of lambda development is also decreased in this genetic background due to impaired N-dependent antitermination. Here, it is demonstrated that despite the reduced level of early lytic pL- and pR-derived transcripts, lytic growth of bacteriophage lambda is not affected in rich media. The level of the late lytic, pR-derived transcripts also remains unaffected by the rpoA341 mutation under these conditions. However, it was found that whilst there is no significant difference in the phage burst size in rpoA+ and rpoA341 hosts growing in rich media, phage lambda is not able to produce progeny in the rpoA341 mutant growing in minimal medium, in contrast to otherwise isogenic rpoA+ bacteria. Provision of an excess of the phage replication proteins O and P in trans or overproduction of the antitermination protein N restore the ability of phage lambda to produce progeny in the rpoA341 mutant under the latter conditions. These results suggest that in rich media phage lambda produces some early proteins in excess of that needed for its effective propagation and indicate that replication proteins may be limiting factors for phage lytic growth in poor media.
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Affiliation(s)
- Magdalena Gabig
- Laboratory of Molecular Genetics, Department of Molecular Biology, University of GdańskKładki 24, 80-822 GdańskPoland
| | - Michal Obuchowski
- Laboratory of Molecular Genetics, Department of Molecular Biology, University of GdańskKładki 24, 80-822 GdańskPoland
| | - Alicja WeLgrzyn
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Laboratory of Molecular Biology affiliated to the University of GdańskK&lstroke;adki 24, 80-822 GdańskPoland
| | - Agnieszka Szalewska-Palasz
- Laboratory of Molecular Genetics, Department of Molecular Biology, University of GdańskKładki 24, 80-822 GdańskPoland
| | - Mark S Thomas
- Division of Molecular and Genetic Medicine, University of Sheffield Medical SchoolBeech Hill Road, Sheffield S10 2RXUK
| | - Grzegorz WeLgrzyn
- Laboratory of Molecular Genetics, Department of Molecular Biology, University of GdańskKładki 24, 80-822 GdańskPoland
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