scholarly journals Formation of Cyclobutane Pyrimidine Dimers after UVA Exposure (Dark-CPDs) Is Inhibited by an Hydrophilic Extract of Polypodium leucotomos

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1961
Author(s):  
Mikel Portillo-Esnaola ◽  
Azahara Rodríguez-Luna ◽  
Jimena Nicolás-Morala ◽  
María Gallego-Rentero ◽  
María Villalba ◽  
...  
Keyword(s):  
Sun Exposure ◽  
Reactive Species ◽  
Cyclobutane Pyrimidine Dimers ◽  
Uva Irradiation ◽  
Pyrimidine Dimers ◽  
Hydrophilic Extract ◽  
Ros Scavenger ◽  
Pre Treatment ◽  
Polypodium Leucotomos ◽  
Uva Radiation

Exposure to sun and especially to ultraviolet radiation (UVR) exerts well known detrimental effects on skin which are implicated in malignancy. UVR induces production of cyclobutane pyrimidine dimers (CPDs), immediately during exposure and even hours after the exposure, these latter being called dark-CPDs, as consequence of the effects of different reactive species that are formed. Fernblock® (FB), an aqueous extract of Polypodium leucotomos, has proven to have photoprotective and antioxidant effects on skin. The aim of our work was to investigate the potential photoprotective effect of FB against dark-CPD formation. Murine melanocytes (B16-F10) were exposed to UVA radiation and the production of dark-CPDs and different reactive oxygen and nitrogen species (ROS and RNS) was measured. Significant dark-CPD formation could be seen at 3h after UVA irradiation, which was inhibited by the pre-treatment of cells with FB. Formation of nitric oxide, superoxide and peroxynitrite was increased after irradiation, consistent with the increased CPD formation. FB successfully reduced the production of these reactive species. Hence, these results show how dark-CPDs are formed in UVA irradiated melanocytes, and that FB acts as a potential antioxidant and ROS scavenger, preventing the DNA damage induced by sun exposure.

scholarly journals Cyclobutane pyrimidine dimers are predominant DNA lesions in whole human skin exposed to UVA radiation

2006 ◽  
Vol 103 (37) ◽  
pp. 13765-13770 ◽  
Author(s):  
S. Mouret ◽  
C. Baudouin ◽  
M. Charveron ◽  
A. Favier ◽  
J. Cadet ◽  
...  
Keyword(s):  
Human Skin ◽  
Dna Lesions ◽  
Cyclobutane Pyrimidine Dimers ◽  
Pyrimidine Dimers ◽  
Uva Radiation

scholarly journals A Role for Histone H2B During Repair of UV-Induced DNA Damage in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1375-1387
Author(s):  
Emmanuelle M D Martini ◽  
Scott Keeney ◽  
Mary Ann Osley
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Chromatin Structure ◽  
Specific Effect ◽  
Cell Killing ◽  
Cyclobutane Pyrimidine Dimers ◽  
Histone H2b ◽  
Uv Sensitivity ◽  
Pyrimidine Dimers

Abstract To investigate the role of the nucleosome during repair of DNA damage in yeast, we screened for histone H2B mutants that were sensitive to UV irradiation. We have isolated a new mutant, htb1-3, that shows preferential sensitivity to UV-C. There is no detectable difference in bulk chromatin structure or in the number of UV-induced cis-syn cyclobutane pyrimidine dimers (CPD) between HTB1 and htb1-3 strains. These results suggest a specific effect of this histone H2B mutation in UV-induced DNA repair processes rather than a global effect on chromatin structure. We analyzed the UV sensitivity of double mutants that contained the htb1-3 mutation and mutations in genes from each of the three epistasis groups of RAD genes. The htb1-3 mutation enhanced UV-induced cell killing in rad1Δ and rad52Δ mutants but not in rad6Δ or rad18Δ mutants, which are defective in postreplicational DNA repair (PRR). When combined with other mutations that affect PRR, the histone mutation increased the UV sensitivity of strains with defects in either the error-prone (rev1Δ) or error-free (rad30Δ) branches of PRR, but did not enhance the UV sensitivity of a strain with a rad5Δ mutation. When combined with a ubc13Δ mutation, which is also epistatic with rad5Δ, the htb1-3 mutation enhanced UV-induced cell killing. These results suggest that histone H2B acts in a novel RAD5-dependent branch of PRR.

scholarly journals The effect of flanking bases on direct and triplet sensitized cyclobutane pyrimidine dimer formation in DNA depends on the dipyrimidine, wavelength and the photosensitizer

2021 ◽  
Author(s):  
Chen Lu ◽  
Natalia Eugenia Gutierrez-Bayona ◽  
John-Stephen Taylor
Keyword(s):  
Uv Light ◽  
Pyrimidine Dimer ◽  
Flanking Sequence ◽  
Quenching Mechanism ◽  
Cyclobutane Pyrimidine Dimers ◽  
Sequence Dependence ◽  
Pyrimidine Dimers ◽  
Skin Cancers ◽  
A Charge ◽  
C To T Mutations

Abstract Cyclobutane pyrimidine dimers (CPDs) are the major products of DNA produced by direct absorption of UV light, and result in C to T mutations linked to human skin cancers. Most recently a new pathway to CPDs in melanocytes has been discovered that has been proposed to arise from a chemisensitized pathway involving a triplet sensitizer that increases mutagenesis by increasing the percentage of C-containing CPDs. To investigate how triplet sensitization may differ from direct UV irradiation, CPD formation was quantified in a 129-mer DNA designed to contain all 64 possible NYYN sequences. CPD formation with UVB light varied about 2-fold between dipyrimidines and 12-fold with flanking sequence and was most frequent at YYYR and least frequent for GYYN sites in accord with a charge transfer quenching mechanism. In contrast, photosensitized CPD formation greatly favored TT over C-containing sites, more so for norfloxacin (NFX) than acetone, in accord with their differing triplet energies. While the sequence dependence for photosensitized TT CPD formation was similar to UVB light, there were significant differences, especially between NFX and acetone that could be largely explained by the ability of NFX to intercalate into DNA.

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