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Totsika M, Beatson SA, Holden N, Gally DL. Regulatory interplay between pap operons in uropathogenic Escherichia coli. Mol Microbiol 2008; 67:996-1011. [DOI: 10.1111/j.1365-2958.2007.06098.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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2
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Regulatory Interactions among adhesin gene systems of uropathogenic Escherichia coli. Infect Immun 2007; 76:771-80. [PMID: 18039830 DOI: 10.1128/iai.01010-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Uropathogenic Escherichia coli strain J96 carries multiple determinants for fimbrial adhesins. The regulatory protein PapB of P fimbriae has previously been implicated in potential coregulatory events. The focB gene of the F1C fimbria determinant is highly homologous to papB; the translated sequences share 81% identity. In this study we investigated the role of PapB and FocB in regulation of the F1C fimbriae. By using gel mobility shift assays, we showed that FocB binds to sequences in both the pap and foc operons in a somewhat different manner than PapB. The results of both in vitro cross-linking and in vivo oligomerization tests indicated that FocB could function in an oligomeric fashion. Furthermore, our results suggest that PapB and FocB can form heterodimers and that these complexes can repress expression of the foc operon. The effect of FocB on expression of type 1 fimbriae was also tested. Taken together, the results that we present expand our knowledge about a regulatory network for different adhesin gene systems in uropathogenic E. coli and suggest a hierarchy for expression of the fimbrial adhesins.
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3
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Abstract
Fimbria-mediated interaction with the host elicits both innate and adaptive immune responses, and thus their expression may not always be beneficial in vivo. Furthermore, the metabolic drain of producing fimbriae is significant. It is not surprising, therefore, to find that fimbrial production in Escherichia coli and Salmonella enterica is under extensive environmental regulation. In many instances, fimbrial expression is regulated by phase variation, in which individual cells are capable of switching between fimbriate and afimbriate states to produce a mixed population. Mechanisms of phase variation vary considerably between different fimbriae and involve both genetic and epigenetic processes. Notwithstanding this, fimbrial expression is also sometimes controlled at the posttranscriptional level. In this chapter, we review key features of the regulation of fimbrial gene expression in E. coli and Salmonella. The occurrence and distribution of fimbrial operons vary significantly among E. coli pathovars and even among the many Salmonella serovars. Therefore, general principles are presented on the basis of detailed discussion of paradigms that have been extensively studied, including Pap, type 1 fimbriae, and curli. The roles of operon specific regulators like FimB or CsgD and of global regulatory proteins like Lrp, CpxR, and the histone-like proteins H-NS and IHF are reviewed as are the roles of sRNAs and of signalling nucleotide cyclic-di-GMP. Individual examples are discussed in detail to illustrate how the regulatory factors cooperate to allow tight control of expression of single operons. Molecular networks that allow coordinated expression between multiple fimbrial operons and with flagella in a single isolate are also presented. This chapter illustrates how adhesin expression is controlled, and the model systems also illustrate general regulatory principles germane to our overall understanding of bacterial gene regulation.
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4
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Lügering A, Benz I, Knochenhauer S, Ruffing M, Schmidt MA. The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K(-): H6) is related to Pap pili but exhibits a truncated regulatory region. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1387-1397. [PMID: 12777480 DOI: 10.1099/mic.0.26266-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Adhesins provide a major advantage for uropathogenic Escherichia coli in establishing urinary tract infections (UTIs). A novel gene cluster responsible for the expression of a filamentous adhesin of the pyelonephritogenic E. coli strain X2194 has been identified, molecularly cloned, and characterized. The 'pix operon' contains eight open reading frames which exhibit significant sequence homology to corresponding genes in the pap operon encoding P pili, the prevalent E. coli adhesins in non-obstructive acute pyelonephritis in humans. Although a pixB gene corresponding to the PapB regulator was identified, a papI homologue could not be found in the pix operon. Instead, a fragment of the R6 gene of the highly uropathogenic E. coli strain CFT073 was identified upstream of pixB. The R6 gene is located in a pathogenicity island containing several pilus-encoding sequences and shows homology to a transposase of Chelatobacter heintzii. In a pixA-lacZ fusion system it was demonstrated that the expression of Pix pili is regulated at the transcriptional level by the R6 gene sequence. A significantly reduced transcription was observed by deleting this fragment and by lowering the growth temperature from 37 to 26 degrees C. In contrast to other filamentous adhesin systems, Pix pili are mainly expressed in the steady state growth phase and were not repressed by the addition of glucose.
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MESH Headings
- Adhesins, Escherichia coli/genetics
- Adhesins, Escherichia coli/physiology
- Amino Acid Sequence
- Base Sequence
- Cloning, Molecular
- DNA, Bacterial/genetics
- Escherichia coli/genetics
- Escherichia coli/pathogenicity
- Escherichia coli/physiology
- Escherichia coli/ultrastructure
- Escherichia coli Infections/etiology
- Fimbriae Proteins/genetics
- Fimbriae Proteins/physiology
- Fimbriae, Bacterial/physiology
- Fimbriae, Bacterial/ultrastructure
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Genes, Regulator
- HeLa Cells
- Humans
- Microscopy, Electron
- Molecular Sequence Data
- Multigene Family
- Operon
- Pyelonephritis/etiology
- Sequence Homology, Amino Acid
- Temperature
- Virulence/genetics
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Affiliation(s)
- Andreas Lügering
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Inga Benz
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Sabine Knochenhauer
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Michael Ruffing
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - M Alexander Schmidt
- Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
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5
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Crost C, Garrivier A, Harel J, Martin C. Leucine-responsive regulatory protein-mediated repression of clp (encoding CS31A) expression by L-leucine and L-alanine in Escherichia coli. J Bacteriol 2003; 185:1886-94. [PMID: 12618452 PMCID: PMC150119 DOI: 10.1128/jb.185.6.1886-1894.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CS31A produced by septicemic and diarrheic Escherichia coli belongs to the Pap-regulatory family of adhesive factors, which are under methylation-dependent transcriptional regulation. Common features of operons encoding members of this family include two conserved GATC sites in the upstream regulatory region, and transcriptional regulators homologue to the PapB and PapI proteins. Methylation protection of GATC sites was previously shown to be dependent on the leucine-responsive regulatory protein (Lrp). Lrp and ClpB, the PapB equivalent, repressed clp basal transcription. A PapI homologue (AfaF) was required together with Lrp to establish the phase variation control, which gave rise to phase-ON cells that expressed CS31A and phase-OFF cells that did not express CS31A. In phase-OFF cells, the GATC(dist) site was methylated and the GATC(prox) site was protected from methylation, whereas in phase-ON cells, the inverse situation was found. Unlike Pap fimbriae, CS31A synthesis was dramatically reduced in media containing L-alanine or L-leucine. L-Alanine prevented the OFF-to-ON switch, locking clp expression in the OFF phase, whereas L-leucine repressed transcription without obvious effect on the switch frequency of phase variation. In phase-variable cells, leucine and alanine promoted methylation of GATC(dist) and methylation protection of GATC(prox), increasing the methylation pattern characteristic of repressed cells. Furthermore, alanine prevented the AfaF-dependent methylation protection of GATC(dist) and thus the appearance of phase-ON cells. In addition, analysis of clp expression in a Lrp-negative background indicated that alanine and leucine also repressed clp transcription by a methylation-independent mechanism.
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Affiliation(s)
- Cécile Crost
- Laboratoire de Microbiologie, Institut National de la Recherche Agronomique, 63122 St-Genès-Champanelle, France
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6
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Abstract
The ability of bacterial pathogens to bind to the host mucosa is a critical step in the pathogenesis of many bacterial infections and, for Escherichia coli, a large number of different fimbrial adhesins have been implicated as virulence factors. In this chapter, our current understanding of the regulatory mechanisms that control the expression of two of the best characterized fimbrial adhesins, pyelonephritis-associated pilus (encoded by pap) and the type 1 fimbria (encoded by fim), will be described. The expression of both fimbrial adhesins is controlled by phase variation (the reversible and apparently random switching between expressing ('on') and non-expressing ('off') states), and is regulated in response to environmental conditions. The phase variation of pap (and of some other fimbriae in Escherichia coli) is determined by the formation of alternative nucleoprotein complexes that either activate (phase 'on') or suppress (phase 'off') transcription of the fimbria genes. Formation of each complex protects a single Dam methylation site (5' GATC) from modification (GATCdist in phase 'on' cells and GATCprox in phase 'off' cells). Furthermore, complex formation is inhibited by methylation of the two 5' GATC sites. Both the phase variation of pap and the transcription of the pap genes in phase 'on' cells, are regulated and expression is subject to both positive and negative feedback control. In contrast to pap, the phase variation of fim is determined by the site-specific inversion of a short element of DNA (the fim switch). In phase 'on' cells, a promoter within the invertible element directs the transcription of the fim structural genes, whereas in phase 'off' cells transcription of the fimbrial genes is silenced. Despite the very different molecular mechanisms controlling the expression of pap and fim, the two systems share many features in common and have probably evolved to fulfill the same function. In addition to details about the molecular mechanisms that control pap and fim, the possible physiological significance of the observed regulation will be discussed.
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Affiliation(s)
- I C Blomfield
- Research School of Biosciences, University of Kent at Canterbury, Canterbury, Kent, CT2 7NJ, UK.
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7
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Huisman TT, de Graaf FK. Negative control of fae (K88) expression by the 'global' regulator Lrp is modulated by the 'local' regulator FaeA and affected by DNA methylation. Mol Microbiol 1995; 16:943-53. [PMID: 7476191 DOI: 10.1111/j.1365-2958.1995.tb02320.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Expression of the K88 (fae) operon is negatively controlled by the co-operative binding of Lrp and FaeA to the fae regulatory region and is dependent on the methylation status of three GATC sites present in this region. In this paper, we describe the binding of Lrp to a T-rich DNA helix between GATC site I and site II. FaeA stabilized and modified the Lrp binding, thereby extending the Lrp footprint over GATC site I and site III. Methylation of GATC site I prevented the binding of Lrp/FaeA at this site and appeared to be essential for the cells, since mutation of this site into GTTC resulted in a lethal overproduction of K88 fimbriae. Methylation of GATC site II and site III reduced the stability of Lrp/FaeA binding. Moreover, methylation of GATC site III stimulated faeB promoter activity. The plasmid population in cells harbouring multiple copies of a K88 plasmid consisted of two differentially methylated forms. Form A plasmids with a methylated GATC site I and site III and a nonmethylated site II (+,-,+) represented 20% of the population and were responsible for high-level expression. Form B plasmids with a methylated GATC site I and a non-methylated site II and site III (+,-,-) represented 80% of the population and were responsible for low-level expression. Apparently, K88 fimbriae expression in vivo is balanced at its maximal possible level by modulation of the methylation status of GATC site III. The ratio (1:4) between these populations is stabilized by a constitutive synthesis of FaeA resulting from the presence of an IS1 insertion upstream of faeA. This IS1 insertion separates the faeA promoter from the FaeB-binding sites, thereby neutralizing the control by FaeB activity on expression of FaeA. Instead, faeA transcription is stimulated by binding of FaeA to the faeA promoter region.
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Affiliation(s)
- T T Huisman
- Department of Molecular Microbiology, Biocentrum Amsterdam, The Netherlands
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8
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Iriarte M, Cornelis GR. MyfF, an element of the network regulating the synthesis of fibrillae in Yersinia enterocolitica. J Bacteriol 1995; 177:738-44. [PMID: 7836309 PMCID: PMC176651 DOI: 10.1128/jb.177.3.738-744.1995] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Yersinia enterocolitica surface antigen Myf is a fibrillar structure that resembles CS3 fimbriae. Gene myfA encodes the 21-kDa major subunit of the antigen, while genes myfB and myfC are required for the transport and assembly of pilin subunits at the bacterial cell surface. Here we show that the expression of Myf is regulated at the transcriptional level by temperature and pH. Gene myfA is transcribed at 37 degrees C and in acidic medium. The transcription start is preceded by a putative -10 box for the vegetative RNA polymerase as well as by sequences resembling the consensus sequence recognized by sigma 28. Thus, myfA could be transcribed either from a classical sigma 70 promoter or from a sigma 28 promoter. Transcription of myfA requires at least two genes, myfF and myfE, situated immediately upstream from myfA. The myfF product does not show similarity to any known regulatory protein. It is an 18.5-kDa protein with no typical helix-turn-helix motif and a unique hydrophobic domain in the NH2-terminal part. T7 expression, osmotic shock, fractionation experiments, and TnphoA fusion analyses carried out in Escherichia coli suggest that MyfF is associated with the inner membrane by means of its hydrophobic domain whereas the hydrophilic part protrudes in the periplasm. These features strikingly evoke ToxS, a protein involved in regulation of Tcp pilus production in Vibrio cholerae. MyfE resembles PsaE, a protein involved in regulation of pH6 antigen in Yersinia pestis. Genes myfF and myfE are presumably part of a whole regulatory network. MyfF could be an element of the signal transducing system.
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MESH Headings
- Amino Acid Sequence
- Antigens, Bacterial/analysis
- Antigens, Bacterial/genetics
- Antigens, Bacterial/physiology
- Antigens, Surface/analysis
- Antigens, Surface/genetics
- Antigens, Surface/physiology
- Base Sequence
- Fimbriae, Bacterial
- Gene Expression Regulation, Bacterial
- Hydrogen-Ion Concentration
- Molecular Sequence Data
- Open Reading Frames
- Promoter Regions, Genetic
- Temperature
- Transcription, Genetic
- Yersinia enterocolitica/genetics
- Yersinia enterocolitica/immunology
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Affiliation(s)
- M Iriarte
- Microbial Pathogenesis Unit, Université Catholique de Louvain, Brussels, Belgium
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9
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Calvo JM, Matthews RG. The leucine-responsive regulatory protein, a global regulator of metabolism in Escherichia coli. Microbiol Rev 1994; 58:466-90. [PMID: 7968922 PMCID: PMC372976 DOI: 10.1128/mr.58.3.466-490.1994] [Citation(s) in RCA: 250] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The leucine-responsive regulatory protein (Lrp) regulates the expression of more than 40 genes and proteins in Escherichia coli. Among the operons that are positively regulated by Lrp are operons involved in amino acid biosynthesis (ilvIH, serA)), in the biosynthesis of pili (pap, fan, fim), and in the assimilation of ammonia (glnA, gltBD). Negatively regulated operons include operons involved in amino acid catabolism (sdaA, tdh) and peptide transport (opp) and the operon coding for Lrp itself (lrp). Detailed studies of a few members of the regulon have shown that Lrp can act directly to activate or repress transcription of target operons. A substantial fraction of operons regulated by Lrp are also regulated by leucine, and the effect of leucine on expression of these operons requires a functional Lrp protein. The patterns of regulation are surprising and interesting: in some cases activation or repression mediated by Lrp is antagonized by leucine, in other cases Lrp-mediated activation or repression is potentiated by leucine, and in still other cases leucine has no effect on Lrp-mediated regulation. Current research is just beginning to elucidate the detailed mechanisms by which Lrp can mediate such a broad spectrum of regulatory effects. Our view of the role of Lrp in metabolism may change as more members of the regulon are identified and their regulation characterized, but at this point Lrp seems to be important in regulating nitrogen metabolism and one-carbon metabolism, permitting adaptations to feast and to famine.
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Affiliation(s)
- J M Calvo
- Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853
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10
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Morschhäuser J, Vetter V, Emödy L, Hacker J. Adhesin regulatory genes within large, unstable DNA regions of pathogenic Escherichia coli: cross-talk between different adhesin gene clusters. Mol Microbiol 1994; 11:555-66. [PMID: 7908714 DOI: 10.1111/j.1365-2958.1994.tb00336.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The uropathogenic Escherichia coli strain 536 possesses two large, unstable DNA regions on its chromosome, which were termed pathogenicity islands (pais). Deletions of pais, which occur with relatively high frequency in vitro and in vivo, lead to avirulent mutants. The genetic determinants for production of haemolysin (Hly) and P-related fimbriae (Prf) are located in one of these islands. Deletion of this pathogenicity island (paill) not only removes the hly- and prf-specific genes, but also represses S fimbriae (Sfa), although the sfa genes of this virulence factor are not located on paill. We have identified two regulatory genes, prfB and prfl, of the prf gene cluster that are homologous to the sfa regulatory genes sfaB and sfaC, respectively. Mutations in sfaB and sfaC that inhibit transcription of the major fimbrial subunit gene sfaA were complemented by the homologous prf genes, suggesting communication between the two fimbrial gene clusters in the wild-type strain. Chromosomal mutagenesis of the two prf regulators in strain 536 repressed transcription of sfaA, detected by Northern hybridization and a chromosomal sfaA-lacZ fusion. In addition, haemagglutination assays measured a lower level of S fimbriae in these mutants. Expression of the cloned prf regulators in trans reversed the effect of the mutations; furthermore, constitutive expression of prfB or prfl could also over-come the repression of S fimbriae in a strain that had lost the pathogenicity islands. Virulence assays in mice established that the prf mutants were less virulent than the wild-type strain. The results demonstrate that cross-regulation of two unlinked virulence gene clusters together with the co-ordinate loss of large DNA regions significantly influences the virulence of an extraintestinal E. coli wild-type isolate.
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Affiliation(s)
- J Morschhäuser
- Institut für Molekulare Infektionsbiologie, Würzburg, Germany
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11
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van der Woude MW, Low DA. Leucine-responsive regulatory protein and deoxyadenosine methylase control the phase variation and expression of the sfa and daa pili operons in Escherichia coli. Mol Microbiol 1994; 11:605-18. [PMID: 7910935 DOI: 10.1111/j.1365-2958.1994.tb00340.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Escherichia coli operons daa and sfa encode F1845 and S pili, respectively. In this paper we show that the expression of these operons is under phase variation control at a transcriptional level. The transcription of both operons is dependent on the global regulator leucine-responsive regulatory protein (Lrp) and deoxyadenosine methylase (Dam). Lrp is required for methylation protection of two GATC sites located within conserved DNA sequences in the regulatory regions of these operons. These GATC sites are differentially methylated, establishing a methylation pattern which is characteristic of either the phase ON or phase OFF state. We also show that Lrp binds to the daa and sfa regulatory regions and that this binding is modulated by the methylation of the GATC sites. These results indicate that the phase variation of the daa and sfa operons is regulated by a mechanism involving differential binding of Lrp owing to methylation of GATC sites in the regulatory region, which is similar to the mechanism that controls phase variation of the pap operon.
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Affiliation(s)
- M W van der Woude
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132
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12
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Morschhäuser J, Uhlin BE, Hacker J. Transcriptional analysis and regulation of the sfa determinant coding for S fimbriae of pathogenic Escherichia coli strains. MOLECULAR & GENERAL GENETICS : MGG 1993; 238:97-105. [PMID: 8097559 DOI: 10.1007/bf00279536] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The sfa determinant codes for S fimbrial adhesins which constitute adherence factors of pathogenic Escherichia coli strains. We have recently shown that the sfa determinant is transcribed from three promoters, pA, pB, and pC. In comparison with the promoters pB and pC, promoter pA, which is located in front of the structural gene sfaA, showed very weak activity. Here we have determined the exact positions of the mRNA start points by primer extension studies. We have also shown that mRNAs of 500, 700 and 1400 bases can be detected using oligonucleotide probes specific for the genes sfaB, sfaC and sfaA. SfaB and SfaC are positive regulators influencing fimbriation and the production of the S-specific adhesin which is encoded by the gene sfaS located in the distal half of the determinant. In addition, it is demonstrated that SfaB and SfaC interfere with the regulatory effect of the histone-like protein H-NS, encoded by a locus termed drdX or osmZ. In a drdX+ strain the regulators are necessary for transcription of the sfa determinant. In contrast, sfa expression is activator-independent in a drdX- strain. In this latter genetic background, a substantial fraction of the sfa transcripts is initiated from promoter pA. On the basis of these data we discuss a model for the regulation of this adhesin-specific determinant.
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MESH Headings
- Adhesins, Escherichia coli
- Bacterial Outer Membrane Proteins/genetics
- Base Sequence
- Cloning, Molecular
- DNA, Recombinant/metabolism
- Escherichia coli/genetics
- Escherichia coli/pathogenicity
- Escherichia coli/physiology
- Fimbriae, Bacterial/physiology
- Frameshift Mutation
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Genes, Fungal
- Genes, Regulator
- Introns
- Models, Genetic
- Molecular Sequence Data
- Oligodeoxyribonucleotides
- Plasmids
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Homology, Nucleic Acid
- Transcription, Genetic
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Affiliation(s)
- J Morschhäuser
- Lehrstuhl für Mikrobiologie im Theodor-Boveri-Institut, Würzburg, FRG
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13
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van der Woude MW, Braaten BA, Low DA. Evidence for global regulatory control of pilus expression in Escherichia coli by Lrp and DNA methylation: model building based on analysis of pap. Mol Microbiol 1992; 6:2429-35. [PMID: 1357527 DOI: 10.1111/j.1365-2958.1992.tb01418.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyelonephritis-associated pilus (Pap) expression is regulated by a phase variation control mechanism involving PapB, Papl, catabolite activator protein (CAP), leucine-responsive regulatory protein (Lrp) and deoxyadenosine methylase (Dam). Lrp and Papl bind to a specific non-methylated pap regulatory DNA region containing the sequence 'GATC' and facilitate the formation of an active transcriptional complex. Evidence indicates that binding of Lrp and Papl to this region inhibits methylation of the GATC site by Dam. However, if this GATC site is first methylated by Dam, binding of Lrp and Papl is inhibited. These events lead to the formation of two different pap methylation states characteristic of active (ON) and inactive (OFF) pap transcription states. The fae (K88), daa (F1845) and sfa (S) pilus operons share conserved 'GATC-box' domains with pap and may be subject to a similar regulatory control mechanism involving Lrp and DNA methylation.
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Affiliation(s)
- M W van der Woude
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
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14
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Forsman K, Sondén B, Göransson M, Uhlin BE. Antirepression function in Escherichia coli for the cAMP-cAMP receptor protein transcriptional activator. Proc Natl Acad Sci U S A 1992; 89:9880-4. [PMID: 1384062 PMCID: PMC50237 DOI: 10.1073/pnas.89.20.9880] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The cAMP receptor protein (CRP) complex (cAMP-CRP) is a global regulator of gene expression. It influences transcription from a number of promoters in Escherichia coli, including two divergently oriented promoters in the pap pili-adhesin gene system. To further define the role of cAMP-CRP in pap regulation we monitored protein-DNA interactions in vitro and levels of pap transcription in vivo in wild-type and mutant pap-containing clones. The results showed that activation was mediated by a single cAMP-CRP-binding site centered at nucleotide positions -215.5 and -115.5 relative to the transcriptional start points. A target for the pap-specific regulatory protein PapB was localized adjacent to the cAMP-CRP-binding site. The long-range effects exerted from the protein-binding sites were consistent with the idea that cAMP-CRP caused a change in the local DNA conformation and that a nucleoprotein complex (involving cAMP-CRP and PapB) was formed in the region between the pap promoters. Moreover, transcription became independent of activation of cAMP-CRP and the PapB protein in a mutant lacking the nucleoid-associated protein H-NS. Our findings suggest that the cAMP-CRP complex mediates its positive regulatory function by alleviating transcriptional silencing and, as such, plays a role as antirepressor.
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Affiliation(s)
- K Forsman
- Department of Microbiology, University of Umeå, Sweden
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15
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Abstract
An invasive Escherichia coli (EIEC) isolate was found to bind basement-membrane laminin in a saturable and time-dependent manner. Excess of unlabelled laminin inhibited the binding of the radioactively labelled protein. Non-invasive E. coli K-12 exhibited only low-level laminin binding but introduction of the virulence-associated plasmid from the EIEC isolate led to high-level binding. Expression of a receptor for laminin on the bacteria was therefore associated with the presence of the virulence plasmid. Scatchard plot analysis indicated approximately 1000 receptors per bacterial cell, and a Kd of high-affinity binding of 0.5 pM. A laminin-binding protein which correlated with the presence of the plasmid was isolated and characterized. Its sequence of the eight amino-terminal amino acids was identical to that of the LamB protein of E. coli, although the molecular mass of the two in sodium dodecyl sulphate/polyacrylamide gel (SDS-PAGE) appeared to be slightly different. Both proteins reacted in immunoblot assays with polyclonal antisera raised against either protein, and both proteins bound laminin. Southern-blot hybridization analysis established that both the EIEC strain and the K-12 strains with or without the virulence plasmid contained one lamB gene only, and no laminin-binding protein appeared when the virulence plasmid was introduced into bacteria deleted for the lamB gene. On the basis of these results we suggest that native LamB protein of E. coli or a modified variant of it serves as a major receptor for laminin binding and is present at an increased level in invasive E. coli containing the virulence plasmid.
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Affiliation(s)
- K H Valkonen
- Department of Biochemistry, University of Oulu, Finland
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Ott M, Bender L, Blum G, Schmittroth M, Achtman M, Tschäpe H, Hacker J. Virulence patterns and long-range genetic mapping of extraintestinal Escherichia coli K1, K5, and K100 isolates: use of pulsed-field gel electrophoresis. Infect Immun 1991; 59:2664-72. [PMID: 1677349 PMCID: PMC258071 DOI: 10.1128/iai.59.8.2664-2672.1991] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A total of 127 extraintestinal Escherichia coli strains of the capsule serotypes K1, K5, and K100 from human and animal sources were analyzed for DNA sequences specific for the genes for various adhesins (P fimbriae [pap] and P-related sequences [prs], S fimbriae [sfa]/F1C fimbriae [foc], and type I fimbriae [fim]), aerobactin (aer), and hemolysin (hly). The expression of corresponding virulence factors was also tested. Twenty-four selected strains were analyzed by long-range DNA mapping to evaluate their genetic relationships. DNA sequences for the adhesins were often found in strains not expressing them, while strains with hemolysin and aerobactin genes usually did express them. Different isolates of the same serotype often expressed different virulence patterns. The use of virulence-associated gene probes for Southern hybridization with genomic DNA fragments separated by pulsed-field gel electrophoresis revealed that a highly heterogeneous restriction fragment length and hybridization pattern existed even within strains of the same serotype. Long-range DNA mapping is therefore useful for the evaluation of genetic relatedness among individual isolates and facilitates the performance of precise molecular epidemiology.
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Affiliation(s)
- M Ott
- Institut für Genetik und Mikrobiologie, Universität Würzburg, Germany
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Schmoll T, Morschhäuser J, Ott M, Ludwig B, van Die I, Hacker J. Complete genetic organization and functional aspects of the Escherichia coli S fimbrial adhesion determinant: nucleotide sequence of the genes sfa B, C, D, E, F. Microb Pathog 1990; 9:331-43. [PMID: 1983079 DOI: 10.1016/0882-4010(90)90067-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The S fimbrial adhesin (sfa) determinant of E. coli comprises nine genes situated on a stretch of 7.9 kilobases (kb) DNA. Here the nucleotide sequence of the genes sfa B and sfa C situated proximal to the main structural gene sfaA is described. Sfa-LacZ fusions show that the two genes are transcribed in opposite directions. The isolation of mutants in the proximal region of the sfa gene cluster, the construction of sfa-phoA gene fusions and subsequent transcomplementation studies indicated that the genes sfa B and sfa C play a role in regulation of the sfa determinant. In addition the nucleotide sequence of the genes sfa D, sfa E and sfa F situated between the genes sfa A and sfa G responsible for S subunit proteins, were determined. It is suggested that these genes are involved in transport and assembly of fimbrial subunits. Thus the entire genetic organization of the sfa determinant is presented and compared with the gene clusters coding for P fimbriae (pap), F1C fimbriae (foc) and type I fimbriae (fim). The evolutionary relationship of fimbrial adhesion determinants is discussed.
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Affiliation(s)
- T Schmoll
- Institut für Genetik und Mikrobiologie, University of Würzburg, Germany
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Use of a wild-type gene fusion to determine the influence of environmental conditions on expression of the S fimbrial adhesin in an Escherichia coli pathogen. J Bacteriol 1990; 172:5103-11. [PMID: 1975582 PMCID: PMC213168 DOI: 10.1128/jb.172.9.5103-5111.1990] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
S fimbrial adhesins (Sfa) enable pathogenic Escherichia coli strains to bind to sialic acid-containing eucaryotic receptor molecules. In order to determine the influence of culture conditions on the expression of the sfa determinant in a wild-type strain, we fused the gene lacZ, coding for the enzyme beta-galactosidase, to the sfaA gene, responsible for the major protein subunit of S fimbriae. By using a plasmid which carries an R6K origin, the sfaA-lac hybrid construct was site-specifically integrated into the chromosome of the uropathogenic E. coli strain 536WT. The expression of lacZ, which was under the control of the sfa wild-type promoters, was now equivalent to the sfa expression of strain 536WT. With the help of this particular wild-type construct, it was demonstrated that the sfa determinant is better expressed on solid media than in liquid broth. The growth rate had a strong influence on Sfa expression under aerobic but not under anaerobic conditions. Production of Sfa was further regulated by catabolite repression, osmolarity, and temperature.
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Göransson M, Forsman P, Nilsson P, Uhlin BE. Upstream activating sequences that are shared by two divergently transcribed operons mediate cAMP-CRP regulation of pilus-adhesin in Escherichia coli. Mol Microbiol 1989; 3:1557-65. [PMID: 2575704 DOI: 10.1111/j.1365-2958.1989.tb00141.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Transcription of the genes encoding pilus-adhesin of serotype F13 in digalactoside-binding Escherichia coli required activation by the cAMP-CRP complex. Analysis of protein-DNA interaction in vitro showed that CRP bound in a cAMP-dependent manner to a sequence located 0.2 kb upstream of the point of transcription initiation of the pilus subunit operon. The cAMP-CRP activation included, in addition to the main pilus operon, the oppositely oriented operon encoding the Papl regulatory protein. Furthermore, the auto-regulatory product of the promoter-proximal gene (papB) in the pilus subunit operon was found to stimulate the papl transcriptional unit. Thus the cAMP-CRP complex and PapB might act in concert and indirectly promote pili synthesis by stimulating expression of the Papl positive regulator. The results of trans-complementation experiments and analyses using lacZ operon fusion derivatives showed that the cAMP-CRP activation also operated directly in cis on the pilus subunit operon. The region containing the CRP binding site appeared to function as an upstream activating sequence since deletion abolished expression even when the pap regulatory proteins Papl and PapB were supplied in trans. The implications for possible mechanisms of transcriptional activation by the cAMP-CRP complex at this novel location between the two oppositely oriented operons are discussed.
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Affiliation(s)
- M Göransson
- Department of Microbiology, University of Umeå, Sweden
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Göransson M, Forsman K, Uhlin BE. Regulatory genes in the thermoregulation of Escherichia coli pili gene transcription. Genes Dev 1989; 3:123-30. [PMID: 2468557 DOI: 10.1101/gad.3.1.123] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Expression of several different pilus adhesins by Escherichia coli is subject to thermoregulation. The surface-located fimbrial structures are present during growth at 37 degrees C but are not produced by cells grown at lower temperatures, such as 25 degrees C. As a step toward understanding the molecular mechanism, we have studied the role of different cistrons of a cloned pilus adhesin gene cluster (pap) from a uropathogenic E. coli isolate. By promoter cloning, mRNA analysis, and expression of subcloned genes in trans, we have identified the papI gene as the mediator of thermoregulation at the level of pilus adhesin gene transcription. Expression of the major pilus subunit gene (papA) and several other pilus protein cistrons appeared to be dependent on stimulation by the papB and papI gene products. Constructs carrying different pap DNA regions indicated that none of the known Pap proteins acts directly as thermosensor. The chromosomal rpoH gene and RpoH sigma factor did not appear to be required for pap transcription, and the thermoregulation of pilus gene transcription must be different from that of the heat shock regulon. By overexpressing the papI gene product from an expression plasmid in trans, we could circumvent the temperature regulation and turn on production of pilus adhesin at low temperature. Our results suggest that the level of mRNA encoding the PapI activator is limiting at low growth temperatures and that thermoregulation is due to a determinant in the papI-papB intercistronic region.
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Affiliation(s)
- M Göransson
- Department of Microbiology, University of Umeå, Sweden
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