Physico-chemical and biological study of excision-repair of UV - irradiated øX174 RF DNA in vitro

Heijneker, H. L.

doi:10.1093/nar/2.11.2147

Cited by 4 publications

(3 citation statements)

References 33 publications

(17 reference statements)

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“…Both bacterial strains are rec+, and it is apparent that there is no effective rescue of damaged single-stranded DNA, despite the possibility of error-prone repair. Similar results have been reported for other purified phage DNAs and other transfecting systems (7,16). One theoretical alternative consistent with these results and yet involving uptake of singlestranded DNA would be if the plasmid duplex were taken up as two separate complementary strands which reannealed to give doublestranded DNA inside the cell.…”

supporting

confidence: 87%

Nature of transforming deoxyribonucleic acid in calcium-treated Escherichia coli

Strike¹,

Humphreys²,

Roberts³

1979

J Bacteriol

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supporting

confidence: 87%

Nature of transforming deoxyribonucleic acid in calcium-treated Escherichia coli

Strike¹,

Humphreys²,

Roberts³

1979

J Bacteriol

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“…Living organisms maintain repair mechanisms to correct damage caused to their DNA by deleterious agents such as radiation or foreign chemicals. Although much of our knowledge concerning repair processes is derived from genetic investigations, more recent efforts have focused on a biochemical approach with purified enzymes thought to be important to repair processes (8,9,11,14) or with more complete quasi-in vitro systems (24,33). Also, it has been possible to monitor steps in the excision repair process with in vitro systems using crude extracts prepared from Escherichia coli and exogenous substrates that contain a known number of damaged sites (23,32).…”

mentioning

confidence: 99%

In Vitro Packaging of UV Radiation-Damaged DNA from Bacteriophage T7

Kuemmerle

Masker

1977

J Virol

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When DNA from bacteriophage T7 is irradiated with UV light, the efficiency with which this DNA can be packaged in vitro to form viable phage particles is reduced. A comparison between irradiated DNA packaged in vitro and irradiated intact phage particles shows almost identical survival as a function of UV dose when Escherichia coli wild type or polA or uvrA mutants are used as the host. Although uvrA mutants perform less host cell reactivation, the polA strains are identical with wild type in their ability to support the growth of irradiated T7 phage or irradiated T7 DNA packaged in vitro into complete phage. An examination of in vitro repair performed by extracts of T7-infected E. coli suggests that T7 DNA polymerase may substitute for E. coli DNA polymerase I in the resynthesis step of excision repair. Also tested was the ability of a similar in vitro repair system that used extracts from uninfected cells to restore biological activity of irradiated DNA. When T7 DNA damaged by UV irradiation was treated with an endonuclease from Micrococcus luteus that is specific for pyrimidine dimers and then was incubated with an extract of uninfected E. coli capable ofremoving pyrimidine dimers and restoring the DNA ofits original (whole genome size) molecular weight, this DNA showed a higher packaging efficiency than untreated DNA, thus demonstrating that the in vitro repair system partially restored the biological activity of UV-damaged DNA.

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“…This greater amount of damage presumably could inhibit the UV induced recovery mechanism from restoring the molecule to a biologically active state. The yield of pyrimidine dimers in both single stranded and replicative form 0X171* DNA is known(20,37).The number of dimers present after both types of DNA molecules have been given a UV dose which results in equal phage producing ability in an induced host can be computed. The host chosen for this calculation…”

mentioning

confidence: 99%

Ultraviolet light induced recovery in Escherichia Coli of radiation damaged bacteriophage deoxyribonucleic acid / by John Randall Silber.

Silber¹

1977

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The ability of ultraviolet light (UV) 0X17^single stranded and replicative form DNA molecules to produce whole phage when transfected into UV irradiated, calcium treated E. coli K12 hosts was investigated. When IT/ irradiated single and replicative form 0X1TU DNA molecules were transfected into UV irradiated wild type hosts, an enhanced survival of the phage producing ability of the DNA was observed over that seen when the transfection was performed with unirradiated wild type hosts. A similar increase in survival was also found for both types of 0X17 ; t DNA molecules when they were transfected into E. coli deficient in excision repair (uvrA-, uvrBor uvrC-) or recombinational repair (recBor recB-recC-). No enhanced survival was found with recAor lex/V-E. coli hosts. The level of the increased phage producing ability for single stranded 0X17D NA was 1.3 to 1.7 times greater than that for the replicative form DNA in all genetic backgrounds which showed enhanced survival. These results suggest the existence of a UV inducible recovery system which participates in the recovery of UV irradiated 0X17^DNA. This recovery system in dependent upon recA and I ox A regulated function.'; but is independent of excision and recombi national repair. The common genetic requirements for the increased survival of both forms of 0X11 h DNA suggest a common mechanism of recovery for both. The greater survival of the single stranded molecule indicates that it is more susceptible to inducible recovery than the replicative form molecule which may be due to the physical differences between the two. The ability of gamma irradiated 0X17'* single stranded and replicative form DNA to produce whole phage when transfected into a UV irradiated, calcium treated E. coli wild type host was also investigated. By adding appropriate radical scavengers to aqueous solutions of the DNA, it was possible to specify which of the water radiolysis radicals was interacting with the DNA. The maximal enhancement of phage producing ability for both types of DNA was observed under conditions which removed the hydroxyl radical allowing the hydrogen radical and the solvated electron to predominate. Scavenging conditions which removed the hydrogen radical and solvated electron as well as the hydroxyl radical resulted in an enhancement of survival only half as large as the maximum. The same was found to be true for scavenging conditions which removed the hydrogen radical and solvated electron only. These results demonstrate the existence of a UV inducible repair system which mediates in the recovery' of 0X17*1 DNA from gamma ray damage. The mechanism of recovery here could possibly be the same as that which affected the UV inducible recovery of UV irradiated 0X17 '4 DNA. From these results, it can also be concluded that the hydrogen radical and the solvated electron produce a type of damage that is more susceptible to inducible recovery than the hydroxyl radical. The hydroxyl radical appears to produce two classes of damage in both the single stranded and replicative ...

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Physico-chemical and biological study of excision-repair of UV - irradiated øX174 RF DNA in vitro

Cited by 4 publications

References 33 publications

Nature of transforming deoxyribonucleic acid in calcium-treated Escherichia coli

Nature of transforming deoxyribonucleic acid in calcium-treated Escherichia coli

In Vitro Packaging of UV Radiation-Damaged DNA from Bacteriophage T7

Ultraviolet light induced recovery in Escherichia Coli of radiation damaged bacteriophage deoxyribonucleic acid / by John Randall Silber.

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