Persistence of thymine dimers in the replicated DNA of <i>Escherichia coli</i> B/r Hcr<sup>+</sup>

Sedliaková, Milena; Brozmanová, J; Mašek, František

doi:10.1016/0014-5793(75)80442-x

Cited by 8 publications

(1 citation statement)

References 10 publications

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“…1) that about half of the original amounts of dimers remain unexcised, being similarly distributed into DNA replicating and that remaining unreplicated. This finding is in agreement with previous observations (Meyn et al, 1974;Sedliakova' et al, 1975a), and suggests that in culture with incomplete dimer excision, similar amounts of dimers occur in both DNA replicated and remaining unreplicated. Thus, under our conditions 1,000-2,000 dimers/cell were in some way managed on replication.…”

Section: Resultssupporting

confidence: 93%

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Sedliaková¹,

Brozmanová²,

Mašek³

et al. 1981

Biophysical Journal

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In Escherichia coli B/r Her+ irradiated with two separate fluences, dimer excision is prematurely interrupted. The present study was designed to follow tha fate of dimers remaining unexcised. The results imply that these dimers (or distortions containing dimers) are transformed on replication from the state of sensitivity to the state of insensitivity to endonuclease from Micrococcus luteus. This conclusion is based on the following findings: (a) dimers were radiochromatographically detectable in DNA replicated after UV, which indicated that they were tolerated on replication. (b) Similar amounts of dimers were detected radiochromatographically both in DNA remaining unreplicated and DNA twice replicated after UV, This along with the low transfer of parental label into daughter DNA, indicated that dimers remained in situ in parental chains. (c) Immediately after UV, all parental DNA contained numerous sites sensitive to the extract from M. luteus. 2 h after UV, a portion of parental DNA still contained a number of endonuclease-sensitive (Es) sites, while another portion of parental DNA and all daughter DNA were free of Es sites. (d) The occurrence of parental DNA free of Es sites was not temporally correlated with dimer excision, but with the first round of DNA replication. (e) The amount of DNA free of Es sites corresponded to the amount of replicated DNA. (f) Separation of replicated and unreplicated DNA, and detection of Es sites in both portions separately showed that the replicated DNA was almost free of Es sites, whereas unreplicated DNA contained a number of such sites.

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Section: Resultssupporting

confidence: 93%

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Sedliaková¹,

Brozmanová²,

Mašek³

et al. 1981

Biophysical Journal

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Repair, replication and survival in UV-irradiatedEscherichia coli

Sedliaková

Slezáriková

1977

Folia Microbiol

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The influence of dimer removal through excision or photoreactivation on the kinetics of DNA synthesis, sedimentation profiles of DNA molecules and survival of cells was investigated in excision-deficient and excision-proficient Escherichia coli K-12 after a flux of 20 J M-2. In excision-deficient cells photoreactivation did not influence the kinetics of DNA synthesis for a long period and the sedimentation properties of DNA synthesized immediately after photoreactivation were influenced only slightly. However, survival was increased remarkably. In excision-proficient cells where dimers were removed through excision, the kinetics of DNA synthesis increased rapidly, normal-sized DNA molecules were synthesized 60 min after irradiation and survival was substantially higher than in the above-mentioned case. This can hardly be interpreted as a more complete repair of dimers by excision because the persistence of dimers in these cells did not significantly influence either the kinetics of DNA synthesis or normalization of DNA molecules and/or survival of cells. It is concluded that persisting dimers play an important role in excision-deficient but not in excision-proficient cells, that a non-dimer damage to DNA causes inhibition of DNA synthesis after UV and that this damage is of primary importance for excision-proficient cells which can easily cope with persisting dimers.

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The later fate of dimers tolerated at replication in Escherichia coli B/r Hcr⁺ thy⁻ trp⁻

1978

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Persistence of thymine dimers in the replicated DNA of Escherichia coli B/r Hcr⁺

Cited by 8 publications

References 10 publications

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Repair, replication and survival in UV-irradiatedEscherichia coli

The later fate of dimers tolerated at replication in Escherichia coli B/r Hcr⁺ thy⁻ trp⁻

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Persistence of thymine dimers in the replicated DNA of Escherichia coli B/r Hcr+

Cited by 8 publications

References 10 publications

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Repair, replication and survival in UV-irradiatedEscherichia coli

The later fate of dimers tolerated at replication in Escherichia coli B/r Hcr+ thy− trp−

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Persistence of thymine dimers in the replicated DNA of Escherichia coli B/r Hcr⁺

The later fate of dimers tolerated at replication in Escherichia coli B/r Hcr⁺ thy⁻ trp⁻