Novel F prime factors able to replicate in Escherichia coli Hfr strains.

Hiraga, Sota

doi:10.1073/pnas.73.1.198

Cited by 67 publications

(16 citation statements)

References 26 publications

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“…Initiation of chromosome replication in Escherichia coli occurs at a fixed point, oriC (Marsh and Worcel, 1977). Minichromosomes are plasmids that replicate autonomously from oriC (Hiraga, 1976; Messer et al ., 1978; von Meyenburg et al ., 1979). They depend on functional DnaA and DnaC products, de novo protein synthesis and RNA polymerase mediated transcription for initiation of bi‐directional replication, thereby resembling their chromosomal counterparts (for review see Messer and Weigel, 1996).…”

Section: Introductionmentioning

confidence: 99%

Distribution of minichromosomes in individual Escherichia coli cells: implications for replication control

Løbner-Olesen

1999

The EMBO Journal

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A novel method was devised to measure the number of plasmids in individual Escherichia coli cells. With this method, involving measurement of plasmid-driven expression of the green fluorescent protein gene by flow cytometry, the copy number distribution of a number of different plasmids was measured. Whereas natural plasmids had fairly narrow distributions, minichromosomes, which are plasmids replicating only from a cloned oriC copy, have a wide distribution, suggesting that there is no copy number control for minichromosomes. When the selection pressure (kanamycin concentration) for minichromosomes was increased, the copy number of minichromosomes was also increased. At up to 30 minichromosomes per host chromosome, replication and growth of the host cell was unaffected. This is evidence that there is no negative element for initiation control in oriC and that there is no incompatibility between oriC located on the chromosome and minichromosome. However, higher copy numbers led to integration of the minichromosomes at the chromosomal oriC and to initiation asynchrony of the host chromosome. At a minichromosome copy number of~30, the cell's capacity for synchronous initiation is exceeded and free minichromosomes will compete out the chromosome to yield inviable cells, unless the minichromosomes are incorporated into the chromosome.

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Section: Introductionmentioning

confidence: 99%

Distribution of minichromosomes in individual Escherichia coli cells: implications for replication control

Løbner-Olesen

1999

The EMBO Journal

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“…Initiation of chromosome replication occurs at a unique site on the chromosome, termed oriC (8). The process involves several proteins, including DnaA protein encoded by the dnaA gene.…”

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confidence: 99%

Requirement of RecBC enzyme and an elevated level of activated RecA for induced stable DNA replication in Escherichia coli

Magee

Kogoma

1990

J Bacteriol

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During SOS induction, Escherichia coli cells acquire the ability to replicate DNA in the absence of protein synthesis, i.e., induced stable DNA replication (iSDR). Initiation of iSDR can occur in the absence of transcription and DnaA protein activity, which are both required for initiation of normal DNA replication at the origin of replication, oriC. In this study we examined the requirement of recB, recC, and recA for the induction and maintenance of iSDR. We found that recB and recC mutations blocked the induction of iSDR by UV irradiation and nalidixic acid treatment. In recB(Ts) strains, iSDR activity induced at 30°C was inhibited by subsequent incubation at 42°C. In addition, iSDR that was induced after heat activation of the RecA441 protein was abolished by the recB21 mutation. These results indicated that the RecBC enzyme was essential not only for SOS signai generation but also for the reinitiation of DNA synthesis following DNA damage. recAo(Con) lexA3(Ind-) strains were found to be capable of iSDR after nalidixic acid treatment, indicating that the derepression of the recA gene and the activation of the elevated level of RecA protein were the necessary and sufficient conditions for the induction of iSDR.

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“…Hiraga then demonstrated that this region of chromosomal DNA, when carried on F’ plasmids, was sufficient to suppress incompatibility of F plasmids to replicate in Hfr strains (105). He first called this region poh + , (permissive on Hfr) and then named the genetic locus “ oriC ” to designate the ori gin of c hromosome replication (105). OriC was more precisely mapped to be in, or near a 1.3 kb Hind III fragment located at 84.3 minutes on the E. coli chromosome (161).…”

Section: An Abbreviated Historymentioning

confidence: 99%

Initiation of DNA Replication

Leonard

Grimwade

2010

EcoSal Plus

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In recent years it has become clear that complex regulatory circuits control the initiation step of DNA replication by directing the assembly of a multicomponent molecular machine (the orisome) that separates DNA strands and loads replicative helicase at oriC , the unique chromosomal origin of replication. This chapter discusses recent efforts to understand the regulated protein-DNA interactions that are responsible for properly timed initiation of chromosome replication. It reviews information about newly identified nucleotide sequence features within Escherichia coli oriC and the new structural and biochemical attributes of the bacterial initiator protein DnaA. It also discusses the coordinated mechanisms that prevent improperly timed DNA replication. Identification of the genes that encoded the initiators came from studies on temperature-sensitive, conditional-lethal mutants of E. coli , in which two DNA replication-defective phenotypes, "immediate stop" mutants and "delayed stop" mutants, were identified. The kinetics of the delayed stop mutants suggested that the defective gene products were required specifically for the initiation step of DNA synthesis, and subsequently, two genes, dnaA and dnaC , were identified. The DnaA protein is the bacterial initiator, and in E. coli , the DnaC protein is required to load replicative helicase. Regulation of DnaA accessibility to oriC , the ordered assembly and disassembly of a multi-DnaA complex at oriC , and the means by which DnaA unwinds oriC remain important questions to be answered and the chapter discusses the current state of knowledge on these topics.

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Novel F prime factors able to replicate in Escherichia coli Hfr strains.

Cited by 67 publications

References 26 publications

Distribution of minichromosomes in individual Escherichia coli cells: implications for replication control

Distribution of minichromosomes in individual Escherichia coli cells: implications for replication control

Requirement of RecBC enzyme and an elevated level of activated RecA for induced stable DNA replication in Escherichia coli

Initiation of DNA Replication

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