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Ostling J, McDougald D, Marouga R, Kjelleberg S. Global analysis of physiological responses in marine bacteria. Electrophoresis 1997; 18:1441-50. [PMID: 9298658 DOI: 10.1002/elps.1150180819] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this paper, we present results from studies on marine Vibrio species, in which complex adaptive responses have been investigated. The results of two-dimensional polyacrylamide gel electrophoresis serve to illustrate the usefulness of a global approach, and how it can be combined with other methodologies in order to achieve an improved understanding of the means by which bacteria adapt to alterations in environmental conditions. The overall strategies described in this paper are particularly useful for studies of bacteria for which efficient genetic tools, background genotypes and in depth physiological data are not yet available.
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Affiliation(s)
- J Ostling
- Department of General and Marine Microbiology, Göteborg University, Sweden
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2
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Hill TM, Sharma B, Valjavec-Gratian M, Smith J. sfi-independent filamentation in Escherichia coli Is lexA dependent and requires DNA damage for induction. J Bacteriol 1997; 179:1931-9. [PMID: 9068638 PMCID: PMC178916 DOI: 10.1128/jb.179.6.1931-1939.1997] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In Escherichia coli, damage to DNA induces the expression of a set of genes known collectively as the SOS response. Part of the SOS response includes genes that repair DNA damage, but another part of the response coordinates DNA replication and septation to prevent untimely cell division. The classic SOS gene product that inhibits cell division is SfiA (or SulA), which binds to FtsZ and prevents septum formation until the DNA damage has been repaired. However, another pathway acts to coordinate DNA replication and cell division when sfiA, or the sfi-dependent pathway, is inoperative. Until recently, little was known of this alternative pathway, which is called the sfi-independent pathway. We report here that sfi-independent filamentation is suppressed by lexA(Ind-) mutations, suggesting that derepression of the LexA regulon is necessary for sfi-independent induction. However, expression of LexA-controlled genes is not sufficient; DNA damage is also required to induce this secondary pathway of cell division inhibition. Furthermore, we postulate that loss of the common regulatory circuitry of the sfi-dependent and sfi-independent pathways by recA or lexA mutants uncouples cell division and DNA replication.
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Affiliation(s)
- T M Hill
- Department of Microbiology and Immunology, University of North Dakota School of Medicine, Grand Forks 58202-9037, USA.
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3
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Skryzpek E, Straley SC. LcrG, a secreted protein involved in negative regulation of the low-calcium response in Yersinia pestis. J Bacteriol 1993; 175:3520-8. [PMID: 8501055 PMCID: PMC204752 DOI: 10.1128/jb.175.11.3520-3528.1993] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The purpose of this study was to define the function of LcrG, the product of the first gene in the lcrGVHyopBD operon of the low-Ca(2+)-response (LCR) virulence plasmid of Yersinia pestis. We created a Y. pestis strain having an in-frame deletion in lcrG. This nonpolar mutant had an abnormal LCR growth phenotype: it was unable to grow at 37 degrees C in the presence of 2.5 mM Ca2+ ("Ca2+ blind") but was able to grow at 37 degrees C when 18 mM ATP was present. At 37 degrees C it failed to downregulate the expression and secretion of its truncated product (LcrG), V antigen, and YopM. All of these mutant properties were complemented by plasmids carrying normal lcrG. However, a nonpolar lcrE mutation and an lcrH mutation (both also causing a Ca(2+)-blind phenotype) were not complemented in this way. The Y. pestis parent strain expressed LcrG at 37 degrees C in the presence and absence of Ca2+ and transported it to the medium when Ca2+ was absent. We identified two LCR-regulated loci, lcrD and yscDEF, required for this transport. Complementation analysis of the Y. pestis lcrR strain previously shown to lack the expression of LcrG showed that the loss of LcrG but not of LcrR caused the Ca(2+)-blind phenotype of that mutant. Taken together, the results show that LcrG is a negative regulator of the LCR, perhaps functioning in Ca2+ sensing along with LcrE.
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Affiliation(s)
- E Skryzpek
- Department of Microbiology and Immunology, Albert B. Chandler Medical Center, University of Kentucky, Lexington 40536-0084
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4
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Hoe NP, Minion FC, Goguen JD. Temperature sensing in Yersinia pestis: regulation of yopE transcription by lcrF. J Bacteriol 1992; 174:4275-86. [PMID: 1624422 PMCID: PMC206210 DOI: 10.1128/jb.174.13.4275-4286.1992] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In Escherichia coli, a yopE::lacZ fusion was found to be regulated by temperature in the presence of the cloned BamHI G fragment of Yersinia pestis plasmid pCD1, which contains the lcrF locus. Increasing the copy number of lcrF relative to that of the yopE reporter had a negligible effect on the induction ratio (26 versus 37 degrees C) but caused large reductions in the absolute levels of yopE transcription. We localized the lcrF gene by monitoring the induction phenotype of BamHI G deletion derivatives. Sequencing revealed an open reading frame capable of encoding a protein of 30.8 kDa. A protein product of this size was detected in a T7 expression system, and LcrF-dependent yopE-specific DNA binding activity was observed. As expected, LcrF exhibited 98% homology to VirF of Yersinia enterocolitica and significant homology to the carboxy termini of other members of the AraC family of transcriptional regulatory proteins. These proteins could be divided into two classes according to function: those regulating operons involved in catabolism of carbon and energy sources and those involved in regulating virulence genes. lcrF::lacZ transcriptional fusions were constructed and analyzed in Y. pestis and E. coli. The activity of the fusions was not affected by the native pCD1 virulence plasmid, an intact lcrF gene, or temperature. Thus, induction of lcrF transcription is not essential for temperature-dependent activation of yopE transcription. A portion of LcrF was found associated with the membrane fraction in E. coli; however, pulse-chase experiments indicated that this result is an artifact of fractionation.
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Affiliation(s)
- N P Hoe
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical Center, Worcester 01655
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Abstract
We have investigated the physical and genetic structure and regulation of the Yersinia pestis yscBCDEF region, previously called lcrC. DNA sequence analysis showed that this region is homologous to the corresponding part of the ysc locus of Yersinia enterocolitica and suggested that the yscBCDEF cistrons belong to a single operon on the low-calcium response virulence plasmid pCD1. Promoter activity measurements of ysc subclones indicated that yscBCDEF constitutes a suboperon of the larger ysc region by revealing promoter activity in a clone containing the 3' end of yscD, intact yscE and yscF, and part of yscG. These experiments also revealed an additional weak promoter upstream of yscD. Northern (RNA) analysis with a yscD probe showed that operon transcription is thermally induced and downregulated in the presence of Ca2+. Primer extension of operon transcripts suggested that two promoters, a moderate-level constitutive one and a stronger, calcium-downregulated one, control full-length operon transcription at 37 degrees C. Primer extension provided additional support for the proposed designation of a yscBCDEF suboperon by identifying a 5' end within yscF, for which relative abundances in the presence and absence of Ca2+ revealed regulation that is distinct from that for transcripts initiating farther upstream. YscB and YscC were expressed in Escherichia coli by using a high-level transcription system. Attempts to express YscD were only partially successful, but they revealed interesting regulation at the translational level.
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Affiliation(s)
- P L Haddix
- Department of Microbiology and Immunology, Albert B. Chandler Medical Center, University of Kentucky, Lexington 40536-0084
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6
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Plano GV, Barve SS, Straley SC. LcrD, a membrane-bound regulator of the Yersinia pestis low-calcium response. J Bacteriol 1991; 173:7293-303. [PMID: 1657887 PMCID: PMC209237 DOI: 10.1128/jb.173.22.7293-7303.1991] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Yersinia pestis, the etiologic agent of bubonic plague, contains a 75-kb virulence plasmid, called pCD1 in Y. pestis KIM. The low-Ca(2+)-response genes of Y. pestis regulate both bacterial growth and the expression of pCD1-encoded virulence determinants in response to temperature and the presence of Ca2+ or nucleotides. This study characterizes the nucleotide sequence and protein product of the lcrD locus. An lcrD mutant, in contrast to the parent Y. pestis, did not undergo growth restriction or induce strong expression of the V antigen when grown under conditions (37 degrees C, no Ca2+) expected to elicit maximal expression of pCD1 genes. DNA sequence analysis of the cloned lcrD locus showed a single open reading frame that could encode a protein with a molecular weight of 77,804 and a pI of 4.88. LcrD was identified as a 70-kDa inner membrane protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis. LcrD membrane topology was investigated by using lcrD-phoA translational fusions generated with the transposon TnphoA. The alkaline phosphatase activities of the resultant hybrid proteins were consistent with a model predicting eight amino-terminal transmembrane segments that anchor a large cytoplasmic carboxyl-terminal domain to the inner membrane.
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Affiliation(s)
- G V Plano
- Department of Microbiology and Immunology, Chandler Medical Center, University of Kentucky, Lexington 40536
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Price SB, Cowan C, Perry RD, Straley SC. The Yersinia pestis V antigen is a regulatory protein necessary for Ca2(+)-dependent growth and maximal expression of low-Ca2+ response virulence genes. J Bacteriol 1991; 173:2649-57. [PMID: 1901573 PMCID: PMC207833 DOI: 10.1128/jb.173.8.2649-2657.1991] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The low-Ca2+ response is a multicomponent virulence regulon of the human-pathogenic yersiniae in which 12 known virulence genes are coordinately regulated in response to environmental cues of temperature, Ca2+, and nucleotides such as ATP. Yersinial growth also is regulated, with full growth yield being permitted at 37 degrees C only if Ca2+ or a nucleotide is present. In this study, we constructed and characterized a mutant Yersinia pestis specifically defective in the gene encoding the V antigen, one of the virulence genes of the low-Ca2+ response. An in-frame internal deletion-insertion mutation was made by removing bases 51 through 645 of lcrV and inserting 61 new bases. The altered lcrV was introduced into the low-Ca2+ response plasmid in Y. pestis by allelic exchange, and the resulting mutant was characterized for its two-dimensional protein profiles, growth, expression of an operon fusion to another low-Ca2+ response virulence operon, and virulence in mice. The mutant had lost its Ca2+ and nucleotide requirement for growth, showed diminished expression of Ca2(+)-and nucleotide-regulated virulence genes, and was avirulent in mice. The mutation could be complemented with respect to the growth property by supplying native V antigen operon sequences in trans in high copy number (on pBR322). Partial complementation of the growth defect and almost complete complementation of the virulence defect were seen with a lower-copy-number complementing replicon (a pACYC184 derivative). The data are consistent with the interpretation that V antigen is bifunctional, with a role in regulating growth and expression of low-Ca2+ response virulence genes in addition to its putative role as a secreted virulence protein.
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Affiliation(s)
- S B Price
- Department of Microbiology and Immunology, Chandler Medical Center, University of Kentucky, Lexington 40536-0084
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Barve SS, Straley SC. lcrR, a low-Ca2(+)-response locus with dual Ca2(+)-dependent functions in Yersinia pestis. J Bacteriol 1990; 172:4661-71. [PMID: 1695896 PMCID: PMC213301 DOI: 10.1128/jb.172.8.4661-4671.1990] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The low-Ca2+ response (Lcr) of Yersinia includes a regulatory cascade and a set of virulence-related proteins, one of which is the V antigen. The regulatory genes modulate both bacterial growth and expression of the virulence-related proteins in response to temperature and the presence of Ca2+ and nucleotides. In this study we defined a new Lcr locus, lcrR, in Yersinia pestis KIM. An lcrR mutant, obtained by insertion mutagenesis, failed to grow at 37 degrees C whether Ca2+ was present or not. However, it grew normally in the presence of ATP, showing that the Ca2(+)- and nucleotide-responsive mechanisms are separate in Y. pestis. The lcrR mutant was avirulent in mice, probably due to its compromised growth at 37 degrees C. beta-Galactosidase measurements and Northern (RNA blot) analysis revealed that lcrR transcription was regulated primarily by temperature. The DNA sequence of the lcrR locus contained a single open reading frame of 441 bases that could encode a protein with a molecular weight of 16,470 and a pI of 10.73. Expression of an lcrR-containing clone in Escherichia coli yielded a 16,000-molecular-weight protein. At 37 degrees C, the lcrR mutant strongly expressed V antigen and initiated lcrGVH transcription whether Ca2+ was present or not, indicating that this mutant had lost the transcriptional downregulation of lcrGVH shown by the parent in the presence of Ca2+. In the absence of Ca2+, the mutant failed to express LcrG, even though lcrGVH mRNA initiated upstream of lcrG at the normal sites. These data suggest that the lcrR locus is necessary for the regulation of LcrG expression in the absence of Ca2+. Therefore, this locus has a dual regulatory role in the low-Ca2+ response.
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Affiliation(s)
- S S Barve
- Department of Microbiology and Immunology, Chandler Medical Center, University of Kentucky, Lexington 40536-0084
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Leung KY, Straley SC. The yopM gene of Yersinia pestis encodes a released protein having homology with the human platelet surface protein GPIb alpha. J Bacteriol 1989; 171:4623-32. [PMID: 2670888 PMCID: PMC210260 DOI: 10.1128/jb.171.9.4623-4632.1989] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In Yersinia pestis KIM, there are 11 Yops (yersinial outer membrane proteins) encoded by the low-Ca2+ response virulence plasmid pCD1. Only Yops M and N are found in easily detectable amounts in the culture medium. In this study, we located and characterized the yopM gene to obtain clues about its role in the virulence of Y. pestis. Rabbit antibody was raised against Yops M and H, copurified from the supernatant of Y. pseudotuberculosis 43(pGW600, pCD1 yopE::Mu dI1[Apr lac]). This antiserum was adsorbed with an Escherichia coli clone that strongly expressed YopH. The resulting YopM-specific antibody was used to screen a HindIII library of pCD1. HindIII-F and several subclones from it expressed YopM in E. coli minicells. A DNA fragment of 1.39 kilobases from HindIII-F was sequenced and found to contain a 367-amino-acid open reading frame capable of encoding a protein with molecular mass (41,566 daltons) and isoelectric point (4.06) similar to those of YopM. The +1 site of the yopM gene was determined by primer extension. The DNA sequence contained repeating structures: 11 pairs of exact direct repeats, two exact inverted repeats, and three palindromes, ranging from 10 to 42 bases in size. One consensus 14-amino-acid sequence was repeated six times in the predicted protein sequence. The YopM sequence shares some significant homology with the von Willebrand factor- and thrombin-binding domain of the alpha chain of human platelet membrane glycoprotein Ib. These findings suggested a testable hypothesis for the function of YopM.
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Affiliation(s)
- K Y Leung
- Department of Microbiology and Immunology, Chandler Medical Center, University of Kentucky, Lexington 40536
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Fernández MF, Cobos A, Hoz L, Hernández PE, Sanz B. Operon fusions of Mu d1(Ap,lac) to thel-proline biosynthetic genes ofescherichia coli K-12. Curr Microbiol 1989. [DOI: 10.1007/bf01570835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Perry RD, Harmon PA, Bowmer WS, Straley SC. A low-Ca2+ response operon encodes the V antigen of Yersinia pestis. Infect Immun 1986; 54:428-34. [PMID: 3021629 PMCID: PMC260179 DOI: 10.1128/iai.54.2.428-434.1986] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Yersinia pestis has a virulence regulon called the low-Ca2+ response that is mediated by the plasmid pCD and manifested as regulation of growth and of expression of several virulence-associated properties by Ca2+ and temperature. We used Mu dI(Ap lac) to obtain a mutation in pCD1 of Y. pestis KIM that rendered the bacteria unable to express one of these properties, the V antigen. This mutant also had lost the Ca2+ requirement for growth at 37 degrees C and was avirulent in mice. Two-dimensional protein gel electrophoresis showed that the Mu dI(Ap lac) insertion had eliminated 13,000- and 18,000-molecular-weight proteins in addition to the V antigen. We mapped the Mu dI(Ap lac) insertion within pCD1, cloned the HindIII fragment spanning the insertion location, prepared two subclones of this fragment, and identified the proteins these clones expressed in Escherichia coli minicells. The data indicated that the V gene lies within an operon containing three genes; lcrG (encoding the 13,000-molecular-weight protein), lcrV (encoding the 38,000-molecular-weight V antigen), and lcrH (encoding the 18,000-molecular-weight protein). Therefore, the V operon contains the structural gene for V antigen, at least one virulence gene, and at least one Ca2+-dependence gene.
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Yother J, Chamness TW, Goguen JD. Temperature-controlled plasmid regulon associated with low calcium response in Yersinia pestis. J Bacteriol 1986; 165:443-7. [PMID: 3944056 PMCID: PMC214438 DOI: 10.1128/jb.165.2.443-447.1986] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Both the low calcium response and virulence in Yersinia pestis strain KIM5 are mediated by genes located on the 75.4-kilobase plasmid pCD1. The results presented here demonstrate the existence of two new genetic loci of pCD1 whose expression is regulated in response to temperature. Levels of transcription in the trtA and trtB loci were elevated 12- to 16-fold at 37 degrees C compared with levels of transcription at 30 degrees C. In addition, the absolute levels of transcription were the highest that have been reported for genes on pCD1. Mutations in trtB also abolished production of the V antigen. Thermal induction at these loci was dramatically reduced in strains harboring a Tn5 insertion in the lcrF locus of pCD1. lcrF lies 33 and 13 kilobases from the trtA and trtB loci, respectively. Thus, lcrF is a positive regulatory gene responsible for temperature-induced transcription of genes required for the low calcium response.
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Straley SC, Bowmer WS. Virulence genes regulated at the transcriptional level by Ca2+ in Yersinia pestis include structural genes for outer membrane proteins. Infect Immun 1986; 51:445-54. [PMID: 3002984 PMCID: PMC262351 DOI: 10.1128/iai.51.2.445-454.1986] [Citation(s) in RCA: 330] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Yersinia pestis, the causative agent of plague, has a virulence determinant called the low-Ca2+ response (Lcr+ phenotype) that confers on the bacterium Ca2+ dependence for growth at 37 degrees C and expression of V antigen. This virulence determinant is common to the three species of Yersinia and is mediated by Lcr plasmids (called pCD in Y. pestis). In this study, we generated insertions of Mu dI1(Ap lac) in pCD1 of Y. pestis KIM, screened for cells showing transcriptional regulation by Ca2+, and obtained inserts that define at least four pCD1 genes. Their patterns of transcription under different growth conditions closely paralleled the pattern of expression of the V antigen. We tested for expression of Lcr-specific yersinial outer membrane proteins (Yops) by the pCD1::Mu dI1(Ap lac) plasmids. Four of the inserts each eliminated expression of a different Yop; one of these Yops was unique to Y. pestis. Two of the insertions affecting Yops caused avirulence, and one caused strongly decreased virulence of Y. pestis in mice. These data indicate that Yops, like the V antigen, are virulence attributes regulated in the low-Ca2+ response.
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Farr SB, Natvig DO, Kogoma T. Toxicity and mutagenicity of plumbagin and the induction of a possible new DNA repair pathway in Escherichia coli. J Bacteriol 1985; 164:1309-16. [PMID: 2933393 PMCID: PMC219331 DOI: 10.1128/jb.164.3.1309-1316.1985] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Actively growing Escherichia coli cells exposed to plumbagin, a redox cycling quinone that increases the flux of O2- radicals in the cell, were mutagenized or killed by this treatment. The toxicity of plumbagin was not found to be mediated by membrane damage. Cells pretreated with plumbagin could partially reactivate lambda phage damaged by exposure to riboflavin plus light, a treatment that produces active oxygen species. The result suggested the induction of a DNA repair response. Lambda phage damaged by H2O2 treatment were not reactivated in plumbagin-pretreated cells, nor did H2O2-pretreated cells reactivate lambda damaged by treatment with riboflavin plus light. Plumbagin treatment did not induce lambda phage in a lysogen, nor did it cause an increase in beta-galactosidase production in a dinD::Mu d(lac Ap) promoter fusion strain. Cells pretreated with nonlethal doses of plumbagin showed enhanced survival upon exposure to high concentrations of plumbagin, but were unchanged in their susceptibility to far-UV irradiation. polA and recA mutants were not significantly more sensitive than wild type to killing by plumbagin. However, xth-1 mutants were partially resistant to plumbagin toxicity. It is proposed that E. coli has an inducible DNA repair response specific for the type of oxidative damage generated during incubation with plumbagin. Furthermore, this response appears to be qualitatively distinct from the SOS response and the repair response induced by H2O2.
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Abstract
The plasmid pCD1 is required for expression of the low-calcium response (LCR), virulence, and production of V antigen in Yersinia pestis KIM. Five independent mutants constitutive for the LCR at 37 degrees C (Lcrc) were obtained through ethyl methanesulfonate mutagenesis followed by ampicillin enrichment. A sixth, spontaneous mutant was obtained directly through ampicillin enrichment. These mutants failed to grow at 37 degrees C regardless of calcium concentration and produced V antigen constitutively at this temperature. All six mutations were located on pCD1. One mutation was mapped to a 1-kilobase region of lcrA. Based on complementation mapping of this mutation, the lcrA locus was divided into two new loci, lcrD and lcrE. This mutation, lcrE1, did not alter the transcription of other genes in the LCR region and was cis-recessive to lcr mutations. Several lower-molecular-weight outer membrane proteins which were observed in the parent strain grown at 37 degrees C in the presence of 2.5 mM calcium were reduced in quantity or absent from the mutant strain.
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16
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Induction and autoregulation of ada, a positively acting element regulating the response of Escherichia coli K-12 to methylating agents. J Bacteriol 1985; 161:888-95. [PMID: 2982792 PMCID: PMC214980 DOI: 10.1128/jb.161.3.888-895.1985] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The ada gene of Escherichia coli K-12, the regulatory locus for the adaptive response to methylating agents, coded for a 39,000-dalton protein. An adjacent gene coding for a 27,000-dalton protein was coregulated with ada. The Ada protein was strongly induced upon exposure of cells to methylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine. An analysis of ada regulation with an ada-lacZ operon fusion showed that ada+ function was required for induction of ada transcription. Derivatives of the ada gene truncated from the 3' end produced proteins which were more potent in stimulating transcription than the product of the intact ada gene, indicating that the transcription-activating function of the Ada protein resided in its amino terminus. The sequence of the ada-regulatory region and the identification of the start site of ada transcription are also presented.
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Nano FE, Shepherd WD, Watkins MM, Kuhl SA, Kaplan S. Broad-host-range plasmid vector for the in vitro construction of transcriptional/translational lac fusions. Gene 1985; 34:219-26. [PMID: 3924739 DOI: 10.1016/0378-1119(85)90130-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A broad-host-range plasmid was constructed that allows the in vitro formation of beta-galactosidase fusions. DNA from the photosynthetic bacterium Rhodopseudomonas sphaeroides was cloned into this plasmid and a number of R. sphaeroides isolates were recovered that had varying levels of beta-galactosidase activity. beta-galactosidase antigenic activity from the fusion strains could be localized immunologically in polypeptides with an Mr of 120 000 or greater. Expression of beta-galactosidase activity under control of fusion derivatives was either very low or nonexistent in Escherichia coli relative to R. sphaeroides, indicating that R. sphaeroides promoters or translational start signals function poorly in E. coli.
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18
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Goguen JD, Yother J, Straley SC. Genetic analysis of the low calcium response in Yersinia pestis mu d1(Ap lac) insertion mutants. J Bacteriol 1984; 160:842-8. [PMID: 6094509 PMCID: PMC215785 DOI: 10.1128/jb.160.3.842-848.1984] [Citation(s) in RCA: 182] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Yersinia pestis strain KIM requires plasmid pCD1 for expression of the low calcium response, plague virulence antigen V, and virulence. We constructed Mu d1(Ap lac) insertion mutants of this plasmid which were unable to express the low calcium response. The insertions mapped to a 17-kilobase region of the plasmid. By determining the orientation of the insertions and examining beta-galactosidase production from the Mu d1 lac genes, we determined that this region contains three units of transcription, one of which is transcribed in a direction opposite the direction of transcription of the other two. Transcription of at least two of these units was induced significantly at 37 degrees C compared with 26 degrees C. Ca2+ (2.5 mM) and ATP (18 mM) had no significant effect on the level of expression of the Mu d1 lac genes of these mutants. All insertions in the region strongly reduced production of the V antigen. Insertions from each unit of transcription also reduced virulence in mice.
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19
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Hantke K. Cloning of the repressor protein gene of iron-regulated systems in Escherichia coli K12. MOLECULAR & GENERAL GENETICS : MGG 1984; 197:337-41. [PMID: 6097798 DOI: 10.1007/bf00330982] [Citation(s) in RCA: 159] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In Escherichia coli the iron uptake systems are regulated by the fur gene product. The synthesis of the outer membrane proteins fiu, fepA, fecA, fhuA, fhuE and cir is derepressed at low iron concentrations in the medium or constitutive in a fur mutant. The fur gene region cloned into pACYC184 was analysed by restriction analysis, Tn1000 mutagenesis and complementation studies. The presence of fur+ plasmids repressed synthesis of the proteins fepA, fecA, fhuE and cir in a chromosomal fur mutant. More quantitatively, the repression to wild-type levels was shown with lac fusions to the genes fiu, fepA and cir. In minicells an 18,000 dalton protein was identified as the fur gene product. Correlated with the fur protein a slightly smaller protein, possibly a degradation product, was observed. The gene fur was mapped on the E. coli chromosome near nagA at about 15.5 min.
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Goldie H. Regulation of transcription of the Escherichia coli phosphoenolpyruvate carboxykinase locus: studies with pck-lacZ operon fusions. J Bacteriol 1984; 159:832-6. [PMID: 6434512 PMCID: PMC215733 DOI: 10.1128/jb.159.3.832-836.1984] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mutants of Escherichia coli containing genetic fusions of lacZ to the pck (phosphoenolpyruvate carboxykinase) locus were isolated by using Mu d(lacZ Ampr) bacteriophage. Synthesis of beta-galactosidase in these strains is regulated by cyclic AMP and glucose (catabolite repression). Synthesis of beta-galactosidase by pck-lacZ fusions was induced in log-phase cells growing on gluconeogenic media, was repressed by glucose, and was also induced up to 100-fold at the onset of stationary phase in LB medium. This stationary-phase induction required cyclic AMP and some other unknown regulatory signal.
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Maurelli AT, Curtiss R. Bacteriophage Mu d1(Apr lac) generates vir-lac operon fusions in Shigella flexneri 2a. Infect Immun 1984; 45:642-8. [PMID: 6236150 PMCID: PMC263343 DOI: 10.1128/iai.45.3.642-648.1984] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Previous studies have demonstrated that expression of virulence in Shigella spp. is controlled by growth temperature. To study the regulation of virulence (vir) genes, we set out to develop a rapid, easily-assayed phenotype with which to measure expression of virulence. This report described a procedure for isolating vir-lac operon fusions in S. flexneri 2a by using the specialized transducing bacteriophage Mu d1(Apr lac) of Casadaban and Cohen (M. Casadaban and S. N. Cohen, Proc. Natl. Acad. Sci. U.S.A. 76:4530-4533, 1976). Mu d1(Apr lac) lysogens were isolated and screened for loss of virulence and for temperature-dependent expression of the lactose genes on Mu d1(Apr lac). A recombinant plasmid carrying the Mu immunity gene was also introduced into lysogens of interest to stabilize the Mu d1(Apr lac) insertion and prevent possible thermal induction at 37 degrees C. The mutant which we isolated failed to penetrate tissue culture cells in the assay for virulence and produced almost 15-fold more beta-galactosidase when grown at 37 degrees C than when grown at 30 degrees C. The site of insertion of Mu d1(Apr lac) in this strain was shown to be in the 140-megadalton plasmid pSf2a140, which is known to be associated with virulence. P1L4-mediated transduction of the insertion into a virulent recipient demonstrated genetic linkage of Mu d1(Apr lac) with loss of virulence and temperature-dependent expression of beta-galactosidase. All of these features fulfill the phenotype expected for a Mu d1(Apr lac)-induced vir-lac operon fusion. This mutant provides us with a means of measuring expression of a gene function required for virulence by assaying for beta-galactosidase. The insertion will also serve as a starting point for mapping of genes on pSf2a140 which are necessary for expression of virulence.
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Yerkes JH, Casson LP, Honkanen AK, Walker GC. Anaerobiosis induces expression of ant, a new Escherichia coli locus with a role in anaerobic electron transport. J Bacteriol 1984; 158:180-6. [PMID: 6425260 PMCID: PMC215396 DOI: 10.1128/jb.158.1.180-186.1984] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Escherichia coli has a formate hydrogenlyase system which allows it to maintain an electron balance during anaerobic growth by passing electrons from formate to H+ ions, thus generating H2. The Mu d1(Ap lac) bacteriophage was used to generate mutants that were defective in passing electrons from formate to benzyl viologen, an artificial electron acceptor. A subset of these mutants was studied in which beta-galactosidase was expressed at much higher levels under anaerobic conditions than under aerobic conditions. If nitrate was present during anaerobic growth, the same levels of beta-galactosidase were seen in these fusion strains as were seen under aerobic conditions. The Mu d1(Ap lac) insertions in these mutants were genetically mapped between mutS and srl and thus define a new locus we have termed ant (anaerobic electron transport). Recombinant lambda derivatives were isolated which complemented the deficiency of the ant mutants in anaerobic electron transport and also carried a trans-acting region of DNA which reduced expression of the ant-lac fusions under anaerobic conditions; a probe to the ant region was generated from one of these recombinant lambda derivatives. Southern hybridization analysis revealed that the four independent ant::Mu d1(Ap lac) fusions we isolated spanned an approximately 5-kilobase region and that all were transcribed in the same direction, counterclockwise on the E. coli genetic map.
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Walker GC. Mutagenesis and inducible responses to deoxyribonucleic acid damage in Escherichia coli. Microbiol Rev 1984; 48:60-93. [PMID: 6371470 PMCID: PMC373003 DOI: 10.1128/mr.48.1.60-93.1984] [Citation(s) in RCA: 886] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Krueger JH, Elledge SJ, Walker GC. Isolation and characterization of Tn5 insertion mutations in the lexA gene of Escherichia coli. J Bacteriol 1983; 153:1368-78. [PMID: 6298183 PMCID: PMC221787 DOI: 10.1128/jb.153.3.1368-1378.1983] [Citation(s) in RCA: 76] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A Mu d(Ap lac)-generated fusion of lacZ to dinD, a gene induced by DNA damage, was used to isolate Tn5 insertion mutations that affect the regulation of the SOS responses. Three mutants were obtained that contained Tn5 insertions genetically linked to the lexA gene and had properties that suggested the mutants were deficient in lexA expression. The lexA protein has been shown to function as the repressor for genes involved in the SOS responses. By Southern blotting experiments, the three Tn5 insertions were physically mapped to distinct locations within the coding region of the lexA gene. The introduction of these mutations in six strains carrying lacZ fusions to different damage-inducible genes resulted in high expression of beta-galactosidase in all but one of the strains. In the dinF fusion strain, lacZ expression was reduced below that seen in a lexA+ background. Physical mapping studies of the dinF locus gave results consistent with the notion that dinF is part of the lexA transcription unit and that a lexA::Tn5 mutation has a polar effect on dinF expression. With certain din-lac fusion strains, a correlation was seen between the amount of beta-galactosidase production and the location of the particular Tn5 insertion within the lexA gene.
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