Integration of the plasmid prophages P1 and P7 into the chromosome of Escherichia coli

Chesney, Robert H.; Scott, June R.; Vapnek, Daniel

doi:10.1016/0022-2836(79)90424-8

Cited by 79 publications

(37 citation statements)

References 43 publications

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“…Except for pSC101, which requires the host dnaA'function for replication (15), it had been thought that neither F, P1, nor Rtsl requires hostencoded DnaA protein for replication since these plasmids show integrative suppression of dnaA(Ts) lethality of the host (7,31,47). On the other hand, Hansen and Yarmolinsky (E. B. Hansen and M. B. Yarmolinsky, Proc.…”

Section: Discussionmentioning

confidence: 99%

Essential DNA sequence for the replication of Rts1

Itoh¹,

Kamio²,

Terawaki³

1987

J Bacteriol

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The promoter sequence of the mini-Rtsl repA gene encoding the 33,000-dalton RepA protein that is essential for replication was defined by RNA polymerase protection experiments and by analyzing RepA protein synthesized in maxicells harboring mini-Rtsl derivatives deleted upstream of or within the presumptive promoter region. The -10 region of the promoter which shows homology to the incII repeat sequences overlaps two inverted repeats. One of the repeats forms a pair with a sequence in the -35 region, and the other forms a pair with the translation initiation region. The replication origin region, ori(Rtsl), which was determined by supplying RepA protein in trans, was localized within 188 base pairs in a region containing three incII repeats and four GATC sequences. Dyad dnaA boxes that exist upstream from the GATC sequences appeared to be dispensable for the origin function, but deletion of both dnaA boxes from oni(Rtsl) resulted in reduced replication frequency, suggesting that host-encoded DnaA protein is involved in the replication of Rtsl as a stimulatory element. Combination of the minimal repA and ori(Rtsl) segments, even in the reverse orientation compared with the natural sequence, resulted in reconstitution of an autonomously replicating molecule.Essential functions for the autonomous replication of plasmid DNA reside in a relatively small stretch (1 to 5 kilobases; minireplicon) of the genome (32). Except for the ColEl type of plasmids, minireplicons include a DNA region(s) that encodes at least one protein that is absolutely required for replication (i.e., Rep protein) (11, 36). The amount of Rep protein appears to mediate the regulation of plasmid replication. Plasmids also carry a unique DNA sequence(s) in which Rep protein may interact together with the host-specified DNA replication machinery to initiate replication (36). The frequency of plasmid replication, which determines the copy number of the plasmid, is believed to be regulated at the level of initiation by regulation of the synthesis of the Rep initiator protein. To understand the replication initiation mechanism, it is important to characterize the DNA sequence of the origin of replication. Essential parts of the origin sequence have been reported for F (10, 30), incFII plasmids (23, 34), R6K (11), pSC101 (44), P1 (2), and Xdv (42).Mini-Rtsl (17), consisting of 1,855 base pairs (bp), was isolated from stringent plasmid Rtsl (41), which belongs to the T-incompatibility group (9). Mini-Rtsl consists of the repA gene encoding the RepA protein (essential for autonomous replication) and the flanking incI and incII direct repeat sequences. In addition, an oriC homologous sequence is located upstream from incII; this sequence carries four GATC sequences with dyad dnaA boxes that have also been found in the oriC region of the chromosomes of several members of the Enterobacteriaceae (48).We identified in this study the promoter sequence for repA and the minimal region of the replication origin of Rtsl, ori(Rtsl). The characteristic structures of t...

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Section: Discussionmentioning

confidence: 99%

Essential DNA sequence for the replication of Rts1

Itoh¹,

Kamio²,

Terawaki³

1987

J Bacteriol

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“…Small-scale DNA preparations, restriction digests, agarose and polyacrylamide gel electrophoresis, the isolation of DNA fragments, the preparation and transformation of competent bacteria and other routine DNA manipulations were as described by Maniatis et al (1982). Chromosomal DNA for cloning into the EMBL cos4 vector was prepared from a 20 ml overnight LB culture as described by Chesney et al (1979) and size-fractionated by caesium chloride gradient centrifugation. High M, DNA was partially digested with Sau3A to generate fragments larger than 35 kilobases (kb), as judged by electrophoresis on a 0.2% agarose gel.…”

Section: E Coli Formate-dependent Nitrite Reductionmentioning

confidence: 99%

Identification of the formate dehydrogenases and genetic determinants of formate-dependent nitrite reduction by Escherichia coli K12

Darwin

Tormay

Page

et al. 1993

Journal of General Microbiology

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The formate dehydrogenases of Escherichia coli involved in electron transfer from formate to nitrite (Nrf activity : nitrite reduction by formate) have been identified. No previously undescribed selenoprotein was detected in bacteria grown under conditions optimal for the expression of Nrf activity. The Nrf activities of single mutants defective in either FdhN or FdhH were between 50 and 60% that of the parental strain. A double mutant defective in both FdhN and FdhH retained less than 10% of the activity of the FdhN+FdhH+ strain. No Nrf activity was detected in a triple mutant defective in FdhN, FdhH and FdhO or in the selC strain. It is concluded that all three of the known formate dehydrogenases of E. coli can contribute to the transfer of electrons from formate to the Nrf pathway. Mutants defective in Nrf activity and cytochrome c552 synthesis were isolated by insertion mutagenesis or identified amongst strains received from the E. coli Genetic Stock Center. The mutations were located in at least three regions of the chromosome, including the 92 to 94 minute region which includesfdhF, the gene encoding FdhH required for formate hydrogenlyase activity. Fine structure mapping by P1 transduction established that the nrf mutations in thefdhF region were due to defects in three separable loci, all of which were independent of but close to fdhF. Clones were isolated from a cosmid library that complemented a deletion extending from fdhF into a region essential for Nrf activity. From these clones, plasmids were isolated that complemented only some of the N r f mutations in the 92 to 94 minute region, confirming the presence of different operons essential for Nrf activity and cytochrome c552 synthesis in this region. Suggested reasons for this genetic complexity include the need for proteins involved in electron transfer from the various formate dehydrogenases to cytochrome c552, for the attachment of the haem group to the apocytochrome and for cytochrome ~5 5 2 export into the periplasm.

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“…Plasmid minipreparations and total DNA were prepared as previously described (1,3,17). Extraction of intact native plasmids from strain NPS3121 was accomplished by the procedure of Kado and Liu (18 PspLib2 by colony probing with the 4.2-kb EcoRI-HindIlI fragment from pPL6.…”

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confidence: 99%

Genetic and transcriptional organization of the hrp cluster of Pseudomonas syringae pv. phaseolicola

1991

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The hrp cluster of Pseudomonas syringae pv. phaseolicola encodes functions that are essential for pathogenicity on bean plants and for the elicitation of the hypersensitive response on resistant plants. The cluster was saturated with insertions of transposon Tn3-spice that served both as a mutagen and as a sensitive reporter of the expression of the target regions. The mutations covered a 17.5-kb segment in strain NPS3121, in which seven hrp::Tn5 insertions had been previously mapped, and regions outside this segment. The cluster is organized into seven distinct complementation groups (hrpL, hrpAB, hrpC, hrpD, hrpE, hrpF, and hrpSR) on the basis of the analysis of over 100 Tn3-spice insertions in plasmids and 43 similar insertions in the chromosome; it spans nearly 22 kb and is chromosomally located. The transcriptional orientation of all genes in the cluster was established by measuring the level of ice nucleation activity of complemented merodiploids carrying chromosomal hrp::inaZ fusions after inoculation in Red Kidney bean leaves. Although all seven loci were actively expressed in Red Kidney bean leaves, none of them was substantially expressed when the bacteria were grown in King B broth medium. Mutations in all loci, except those in hrpC, greatly reduced the ability of the bacteria to multiply in bean leaves. Mutations in the hrpC locus, although preventing the bacteria from eliciting a hypersensitive reaction on tobacco, allowed the bacteria to produce delayed and attenuated symptoms in Red Kidney bean leaves and to multiply to a level 102. to 103-fold lower than that of the wild-type strain. This is the first comprehensive report of the genetic and transcriptional organization of the hrp gene cluster in a phytopathogenic bacterium.The bean halo blight pathogen, Pseudomonas syringae pv. phaseolicola, possesses a group of genes, designated hrp ("harp"), that are essential for the development of disease symptoms and for the elicitation of the hypersensitive reaction on resistant plants. The majority of known hrp genes in this bacterium are clustered in a large genomic region that has been designated the hrp cluster, whereas one locus (hrpM) is located elsewhere in the genome (24,29,31,36). Besides P. syringae pv. phaseolicola, hrp genes and/or gene clusters from several other members of the P. syringae taxon have been described and cloned (5, 13-16, 24, 30, 33, 37-39), as have those from phylogenetically distinct plant pathogens, such as Pseudomonas solanacearum (2, 14), Erwinia amylovora (44, 45), and some pathovars of Xanthomonas campestris (2,6,42). Homology between hrp genes has been reported among members of the P. syringae taxon (8a, 24) as well as between P. solanacearum and members of the X. campestris group (2).The nature and precise role of most hrp gene products in the plant-bacterium interaction are unknown. Three hrp loci have been analyzed in some detail in P. syringae pv. phaseolicola. A locus designated hrpS encodes a protein that shares sequence similarity to NtrC-like regulatory proteins (...

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Integration of the plasmid prophages P1 and P7 into the chromosome of Escherichia coli

Cited by 79 publications

References 43 publications

Essential DNA sequence for the replication of Rts1

Essential DNA sequence for the replication of Rts1

Identification of the formate dehydrogenases and genetic determinants of formate-dependent nitrite reduction by Escherichia coli K12

Genetic and transcriptional organization of the hrp cluster of Pseudomonas syringae pv. phaseolicola

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