Regulation of DNA synthesis and capacity for initiation in DNA temperature sensitive mutants of Escherichia coli

Eberle, Helen; Forrest, Nancy

doi:10.1007/bf00422913

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…Temperature sensitive mutants which phenotypes are normal or near normal at permissive temperatures, but their mutational phenotypes are apparent at higher or lower temperatures, have been used to study genetic and biochemical processes such as DNA synthesis (Eberle and Forrest 1982), cell wall biogenesis (Kitagaki et al 2004), cell cycle regulation, and cell proliferation (Wang et al 2004;Addinall et al 2005). Temperature sensitive chlorophyll mutants are useful tools for the study of biogenesis and biochemical processes of the chloroplasts in higher plants.…”

Section: Introductionmentioning

confidence: 99%

Identification and fine mapping of a thermo-sensitive chlorophyll deficient mutant in rice (Oryza sativa L.)

Liu

et al. 2007

Planta

116

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A thermo-sensitive chlorophyll deficient mutant was isolated from more than 15,000 transgenic rice lines. The mutant displayed normal phenotype at 23 degrees C or lower temperature (permissive temperature). However, when grown at 26 degrees C or higher (nonpermissive temperature) the plant exhibited an abnormal phenotype characterized by yellow green leaves. Genetic analysis revealed that a single nuclear-encoded recessive gene is responsible for the mutation, which is tentatively designed as cde1(t) (chlorophyll deficient 1, temporally). PCR analysis and hygromycin resistance assay indicated the mutation was not caused by T-DNA insertion. To isolate the cde1(t) gene, a map-based cloning strategy was employed and 15 new markers (five SSR and ten InDels markers) were developed. A high-resolution physical map of the chromosomal region around the cde1(t) gene was made using F(2) and F(3) population consisting of 1,858 mutant individuals. Finally, the cde1(t) gene was mapped in 7.5 kb region between marker ID10 and marker ID11 on chromosome 2. Sequence analysis revealed only one candidate gene, OsGluRS, in the 7.5 kb region. Cloning and sequencing of the target region from the cde1(t) mutant showed that a missense mutation occurred in the mutant. So the OsGluRS gene (TIGR locus Os02 g02860) which encode glutamyl-tRNA synthetase was identified as the Cde1(t) gene.

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Section: Introductionmentioning

confidence: 99%

Identification and fine mapping of a thermo-sensitive chlorophyll deficient mutant in rice (Oryza sativa L.)

Liu

et al. 2007

Planta

116

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“…In the case of the water-clock, however, the phase transition that results from the decrease in water availability would not be completely disrupted by the randomly replicating chromosome and hence would still be able to trigger the replication of the minichromosomes. Decreased water availability following a lowering of temperature (Watson et al, 2023) might also help explain the otherwise puzzling multiple initiation events that occur when a dnaA(ts) mutant is transferred from a non-permissive to a permissive temperature in the absence of protein synthesis (Eberle & Forrest, 1982).…”

Section: Discussionmentioning

confidence: 99%

Hypothesis: bacteria live on the edge of phase transitions with a cell cycle regulated by a water-clock

2024

Preprint

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A fundamental problem in biology is how cells obtain the reproducible, coherent phenotypes needed for natural selection to act or, put differently, how cells manage to limit their exploration of the vastness of phenotype space. A subset of this problem is how they regulate their cell cycle. Bacteria, like eukaryotic cells, are highly structured and contain scores of hyperstructures or assemblies of molecules and macromolecules. The existence and functioning of certain of these hyperstructures depend on phase transitions. Here, I propose a conceptual framework to facilitate the development of water-clock hypotheses in which cells use water to generate phenotypes by living ‘on the edge of phase transitions’. I give an example of such a hypothesis in the case of the bacterial cell cycle and show how it offers a relatively novel ‘view from here’ that brings together a range of different findings about hyperstructures, phase transitions and water and that can be integrated with other hypotheses about differentiation, metabolism and the origins of life.

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“…Eberle and collaborators performed a series of experiments that largely entailed shifting a growing culture of a dnaA(ts) strain (and sometimes a dnaC(ts) strain) to the non-permissive temperature for an hour and then returning that culture to the permissive temperature in the presence or absence of chloramphenicol; in the former case, this resulted in four to five initiation events, as opposed to just one in the latter case [ 152 ]. Only ten minutes of inhibition of protein synthesis were needed to produce these extra initiations [ 153 ]. Could seeing initiation in terms of hyperstructure dynamics help explain these results?…”

Section: Miscellaneous Questionsmentioning

confidence: 99%

Open Questions about the Roles of DnaA, Related Proteins, and Hyperstructure Dynamics in the Cell Cycle

Kohiyama,

Herrick,

Norris

2023

Life

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The DnaA protein has long been considered to play the key role in the initiation of chromosome replication in modern bacteria. Many questions about this role, however, remain unanswered. Here, we raise these questions within a framework based on the dynamics of hyperstructures, alias large assemblies of molecules and macromolecules that perform a function. In these dynamics, hyperstructures can (1) emit and receive signals or (2) fuse and separate from one another. We ask whether the DnaA-based initiation hyperstructure acts as a logic gate receiving information from the membrane, the chromosome, and metabolism to trigger replication; we try to phrase some of these questions in terms of DNA supercoiling, strand opening, glycolytic enzymes, SeqA, ribonucleotide reductase, the macromolecular synthesis operon, post-translational modifications, and metabolic pools. Finally, we ask whether, underpinning the regulation of the cell cycle, there is a physico-chemical clock inherited from the first protocells, and whether this clock emits a single signal that triggers both chromosome replication and cell division.

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Regulation of DNA synthesis and capacity for initiation in DNA temperature sensitive mutants of Escherichia coli

Cited by 8 publications

References 19 publications

Identification and fine mapping of a thermo-sensitive chlorophyll deficient mutant in rice (Oryza sativa L.)

Identification and fine mapping of a thermo-sensitive chlorophyll deficient mutant in rice (Oryza sativa L.)

Hypothesis: bacteria live on the edge of phase transitions with a cell cycle regulated by a water-clock

Open Questions about the Roles of DnaA, Related Proteins, and Hyperstructure Dynamics in the Cell Cycle

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