Far‐UV‐lnduced Dimeric Photoproducts in Short Oligonucleotides: Sequence Effects

Douki, Thierry; Zalizniak, Tatiana; Cadet, Jean

doi:10.1111/j.1751-1097.1997.tb08639.x

Cited by 42 publications

(35 citation statements)

References 54 publications

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“…Thymine (6-4) photoproduct was produced in a lower yield than the related cis-syn cyclobutane dimer upon both UVC and UVB irradiation. The predominance of the formation of cyclobutane dimers at the thymine-thymine sequence has already been observed using dinucleoside monophosphates as model systems (32,53). In addition, indirect methods have shown that cyclobutane pyrimidine dimers are produced in higher yields than (6-4) photoproducts (54), even though the different bipyrimidine sequences could not be taken into consideration.…”

Section: Discussionmentioning

confidence: 96%

“…The (6-4) photoproduct solution was calibrated by measuring its absorbance at 320 nm. The concentration was determined by using the molecular absorption coefficient of the compound reported in the literature (32). An aliquot fraction of the latter solution was exposed to UVB light for increasing periods of time until no residual absorbance in the UVB region remained.…”

Section: Preparation Of Calibrated Solution Of Thymidylyl-(3ј-5ј)-thymentioning

confidence: 99%

“…This was achieved by the sequential use of phosphodiesterases hydrolyzing DNA first from the 5Ј-end to the 3Ј-end and then from the 3Ј-end to the 5Ј-end. Indeed, previous works have shown that the progression of phosphodiesterases is blocked by the presence of either a cyclobutane dimer or a (6-4) photoproduct (32,39). It should be mentioned that nuclease P1 and alkaline phosphatase treatments were added to the enzymatic digestion procedure.…”

Section: Hplc-ms/ms Analysis Of Tpt Photoproducts-electrospray Ionizamentioning

confidence: 99%

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Formation of the Main UV-induced Thymine Dimeric Lesions within Isolated and Cellular DNA as Measured by High Performance Liquid Chromatography-Tandem Mass Spectrometry

Douki¹,

Court²,

Sauvaigo³

et al. 2000

Journal of Biological Chemistry

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228

194

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UVB radiation-induced formation of dimeric photoproducts at bipyrimidine sites within DNA has been unambiguously associated with the lethal and mutagenic properties of sunlight. The main lesions include the cyclobutane pyrimidine dimers and the pyrimidine (6-4) pyrimidone adducts. The latter compounds have been shown in model systems to be converted into their Dewar valence isomers upon exposure to UVB light. A new direct assay, based on the use of liquid chromatography coupled to tandem mass spectrometry, is now available to simultaneously detect each of the thymine photoproducts. It was applied to the determination of the yields of formation of the thymine lesions within both isolated and cellular DNA exposed to either UVC or UVB radiation. The cis-syn cyclobutane thymine dimer was found to be the major photoproduct within cellular DNA, whereas the related (6-4) adduct was produced in an approximately 8-fold lower yield. Interestingly, the corresponding Dewar valence isomer could not be detected upon exposure of human cells to biologically relevant doses of UVB radiation.Ultraviolet radiation represents the most deleterious part of solar light to cells and has been associated with the occurrence of skin cancer (1). UVB (290 -320 nm) radiation is highly mutagenic (2, 3) and mostly induces mutations at bipyrimidine sites in cellular DNA (4 -7). Interestingly, a similar mutation spectrum was observed in the p53 gene of skin tumors cells (8,9). Altogether, these data outlined the biological role of dimeric photoproducts of pyrimidine DNA bases. In the last four decades, major efforts have been devoted to the isolation and the characterization of bipyrimidine photolesions in model compounds and isolated DNA (for reviews, see Refs. 10 and 11). These include the cis-syn and trans-syn diastereoisomers of cyclobutane dimers and the pyrimidine (6-4) pyrimidone adducts (Fig. 1). The latter lesions have been shown to undergo an efficient photoconversion into their Dewar valence isomers upon exposure to UVB light (12).Information on the rate of formation of each specific photoproduct is still needed. Indeed, most of the assays developed for the detection of UV-induced photoproducts within DNA involve the use of indirect methods that do not allow differentiation, for a given class of photoproduct, of the lesions arising from the different possible bipyrimidinic sequences. Cyclobutane pyrimidine dimers have been extensively detected by using T4 endonuclease V, which exhibits a N-glycosylase activity at the 5Ј-extremity of the lesion (13). This leads to the formation of strand breaks, which can be quantified using electrophoretic techniques. A second DNA repair system, namely the Escherichia coli Uvr ABC complex, has been used in combination with a photolyase for the quantitation of cyclobutane dimers and (6-4) photoproducts (14). Another widely applied biochemical approach involves the use of either polyclonal or monoclonal antibodies able to recognize specific classes of pyrimidine photoproducts (15)(16)(17)(18)(19)(20)(21)...

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Section: Discussionmentioning

confidence: 96%

Section: Preparation Of Calibrated Solution Of Thymidylyl-(3ј-5ј)-thymentioning

confidence: 99%

Section: Hplc-ms/ms Analysis Of Tpt Photoproducts-electrospray Ionizamentioning

confidence: 99%

See 1 more Smart Citation

Formation of the Main UV-induced Thymine Dimeric Lesions within Isolated and Cellular DNA as Measured by High Performance Liquid Chromatography-Tandem Mass Spectrometry

Douki¹,

Court²,

Sauvaigo³

et al. 2000

Journal of Biological Chemistry

Self Cite

228

194

View full text Add to dashboard Cite

show abstract

“…1 The data presently available do not allow us to favor one of the above hypotheses. 10 and 4600 M -1 cm -1 , 14 respectively. The T<>T concentrations are calculated considering that the formation of one dimer results to the depletion of two thymine residues and that the ε of (dT)20 at 290 nm is 1780 M -1 cm -1 per base 15 In conclusion, this investigation constitutes the first insight regarding the time-scales at which the two major classes of pyrimidine dimers are formed.…”

Section: Figurementioning

confidence: 94%

Time-Resolved Study of Thymine Dimer Formation

2005

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The formation of thymine dimers in the single-stranded oligonucleotide, (dT)20, is studied at room temperature by laser flash photolysis using 266 nm excitation. It is shown that the (6-4) adduct is formed within 4 ms via a reactive intermediate. The formation of cyclobutane dimers is faster than 200 ns. The overall quantum yield for the (6-4) formation is (3.7 ± 0.3) × 10-3, and that of the cyclobutane dimers is (2.8 ± 0.2) × 10-2. No triplet absorption is detected, showing that either the intersystem crossing yield decreases by 1 order of magnitude upon oligomerization (<1.4 × 10-3) or the triplet state reacts with unit efficiency in less than 200 ns to yield cyclobutane dimers.

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“…The reversion of the pyrimidine dimers induced by the wavelength shorter than 260 nm has been detected earlier [14,[30][31][32]. However, the quantification of the wavelength dependence of the reversion process in the UV-C range remained uninvestigated probably because of the lack of biological relevance of the short wavelengths on the Earth's surface.…”

Section: Ground Based Simulationmentioning

confidence: 99%

Biological ultraviolet Dosimetry in Low Earth’s Orbit

Egyeki¹

2013

Astrobiol Outreach

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The biological dosimetry of the solar UV radiation functioned correctly on the Earth's surface. The aim of the present studies was to extend the dosimetry to the extraterrestrial solar radiation in LEO. Similar to the Earth's surface bacteriophage T7 and polycrystalline uracil thin layers were used as detectors and exposed to the simulated and to the real space environmental parameters aiming to perform the in situ biological UV dosimetry in the space, more exactly on the external pallet of the ISS. The UV detectors have been used in specific cases in thin layer form. In contrast to the Earth's surface the extraterrestrial solar UV radiations contains wavelength components (λ ~ 190-200 nm), which cause photolesions (photoproducts) in the nucleic acids/their components similar to the UV-B photons. However, these wavelengths cause not only photolesions but with a wavelength-dependent efficiency the reversion of some photolesion, too. Our biological detectors measured either in simulation or in situ conditions the resultant of both reactions induced by the extraterrestrial UV radiation. From this aspect the role of the photoreversion in the extension of the biological UV dosimetry and in the survival of the living systems in the space are discussed.

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Far‐UV‐lnduced Dimeric Photoproducts in Short Oligonucleotides: Sequence Effects

Cited by 42 publications

References 54 publications

Formation of the Main UV-induced Thymine Dimeric Lesions within Isolated and Cellular DNA as Measured by High Performance Liquid Chromatography-Tandem Mass Spectrometry

Formation of the Main UV-induced Thymine Dimeric Lesions within Isolated and Cellular DNA as Measured by High Performance Liquid Chromatography-Tandem Mass Spectrometry

Time-Resolved Study of Thymine Dimer Formation

Biological ultraviolet Dosimetry in Low Earth’s Orbit

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