The reduction of thymine residues in DNA by the combined action of UV light and hypophosphite

Yakovlev, D. Yu.; Skuridin, S. G.; Khomutov, Alex R.; Yevdokimov, Yu. M.; Khomutov, R. M.

doi:10.1016/1011-1344(95)07134-n

Cited by 5 publications

(3 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dihydrouracil and dihydrothymine, the substrates of DHO, are intermediates of the reductive pathway for pyrimidine degradation, which also provides β-alanine for pantothenate synthesis (Cambell 1956;Vogels and van der Drift 1976). In addition, ultraviolet radiation induces conversion of pyrimidines in DNA into dihydrouracil, dihydrothymine and dihydrocytosine (Wierzchowski and Schugar 1957;Yakovlev et al 1995). Subsequent base-or nucleotide excision repair can lead to direct or indirect release of these dihydropyrimidines in cells (Venkhataraman et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Identification of fungal dihydrouracil-oxidase genes by expression in Saccharomyces cerevisiae

Bouwknegt

Vos

Ortiz‐Merino

et al. 2022

Antonie van Leeuwenhoek

View full text Add to dashboard Cite

Analysis of predicted fungal proteomes revealed a large family of sequences that showed similarity to the Saccharomyces cerevisiae Class-I dihydroorotate dehydrogenase Ura1, which supports synthesis of pyrimidines under aerobic and anaerobic conditions. However, expression of codon-optimised representatives of this gene family, from the ascomycete Alternaria alternata and the basidiomycete Schizophyllum commune, only supported growth of an S. cerevisiae ura1Δ mutant when synthetic media were supplemented with dihydrouracil. A hypothesis that these genes encode NAD(P)+-dependent dihydrouracil dehydrogenases (EC 1.3.1.1 or 1.3.1.2) was rejected based on absence of complementation in anaerobic cultures. Uracil- and thymine-dependent oxygen consumption and hydrogen-peroxide production by cell extracts of S. cerevisiae strains expressing the A. alternata and S. commune genes showed that, instead, they encode active dihydrouracil oxidases (DHO, EC1.3.3.7). DHO catalyses the reaction dihydrouracil + O2 → uracil + H2O2 and was only reported in the yeast Rhodotorula glutinis (Owaki in J Ferment Technol 64:205–210, 1986). No structural gene for DHO was previously identified. DHO-expressing strains were highly sensitive to 5-fluorodihydrouracil (5F-dhu) and plasmids bearing expression cassettes for DHO were readily lost during growth on 5F-dhu-containing media. These results show the potential applicability of fungal DHO genes as counter-selectable marker genes for genetic modification of S. cerevisiae and other organisms that lack a native DHO. Further research should explore the physiological significance of this enigmatic and apparently widespread fungal enzyme.

show abstract

Section: Discussionmentioning

confidence: 99%

Identification of fungal dihydrouracil-oxidase genes by expression in Saccharomyces cerevisiae

Bouwknegt

Vos

Ortiz‐Merino

et al. 2022

Antonie van Leeuwenhoek

View full text Add to dashboard Cite

show abstract

“…It has been reported that although UV irradiation of dThd solution at 254 nm generates dThd cyclobutane dimers, it generates DHdThd as a major product in the presence of reducing agents such as NaHSO 3 and NaH 2 PO 2 [ 11 , 27 , 28 ]. In the presence of acetone, a photosensitizer, UV irradiation of dThd at 313 nm generates DHdThd and 5-acetonyl-DHdThd, an acetone adduct of dThd, as minor products in addition to dThd cyclobutane dimers [ 17 ].…”

Section: Resultsmentioning

confidence: 99%

α-Tocopherol phosphate as a photosensitizer in the reaction of nucleosides with UV light: formation of 5,6-dihydrothymidine

Suzuki

Ono

2022

Genes and Environ

View full text Add to dashboard Cite

Introduction α-Tocopherol phosphate, a natural water-soluble α-tocopherol analog, exists in biological tissues and fluids. Synthesized α-tocopherol phosphate is used as an ingredient of cosmetics. Findings When a neutral mixed solution of 2′-deoxycytidine, 2′-deoxyguanosine, thymidine, and 2′-deoxyadenosine was irradiated with UV light at wavelengths longer than 300 nm in the presence of α-tocopherol phosphate, thymidine was markedly consumed in an α-tocopherol phosphate dose-dependent manner, whereas other nucleosides only slightly decreased. Two major product peaks were detected in an HPLC chromatogram. The products were identified as diastereomers of 5,6-dihydrothymidine. The addition of radical scavengers had almost no effects on the generation of 5,6-dihydrothymidine, whereas the reactions of nucleosides other than thymidine were suppressed. Trolox, another water-soluble α-tocopherol analog, did not generate 5,6-dihydrothymidine, although all nucleosides were slightly consumed. When UV irradiation of thymidine with α-tocopherol phosphate was conducted in D2O, two deuterium atoms were added to 5 and 6 positions of thymidine with both syn and anti configurations. The ratio of syn and anti configurations alternated depending on pD of the solution. Conclusions The results indicate that α-tocopherol phosphate is a photosensitizer of nucleosides, especially thymidine, and that it introduces two hydrogen atoms to thymidine from H2O, generating 5,6-dihydrothymidine.

show abstract

Section: Discussionmentioning

confidence: 99%

Identification of fungal dihydrouracil-oxidase genes by expression in Saccharomyces cerevisiae

Bouwknegt

Vos²,

Ortiz‐Merino³

et al. 2022

Preprint

View full text Add to dashboard Cite

Analysis of predicted fungal proteomes revealed a large family of sequences that showed similarity to the Saccharomyces cerevisiae Class-I dihydroorotate dehydrogenase Ura1, which supports synthesis of pyrimidines under aerobic and anaerobic conditions. However, expression of codon-optimised representatives of this gene family, from the ascomycete Alternaria alternata and the basidiomycete Schizophyllum commune, only supported growth of an S. cerevisiae ura1Δ mutant when synthetic media were supplemented with dihydrouracil. A hypothesis that these genes encode NAD(P)+-dependent dihydrouracil dehydrogenases (EC 1.3.1.1 or 1.3.1.2) was rejected based on absence of complementation in anaerobic cultures. Uracil- and thymine-dependent oxygen consumption and hydrogen-peroxide production by cell extracts of S. cerevisiae strains expressing the A. alternata and S. commune genes showed that, instead, they encode active dihydrouracil oxidases (DHO, EC1.3.3.7). DHO catalyses the reaction dihydrouracil + O2 → uracil + H2O2 and was only reported in the yeast Rhodotorula glutinis. No structural gene for DHO was previously identified. DHO-expressing strains were highly sensitive to 5-fluoro-dihydrouracil (5F-dhu) and plasmids bearing expression cassettes for DHO were readily lost during growth on 5F-dhu-containing media. These results show the potential applicability of fungal DHO genes as counter-selectable marker genes for genetic modification of S. cerevisiae and other organisms that lack a native DHO. Further research should explore the physiological significance of this enigmatic and apparently widespread fungal enzyme.

show abstract

The reduction of thymine residues in DNA by the combined action of UV light and hypophosphite

Cited by 5 publications

References 10 publications

Identification of fungal dihydrouracil-oxidase genes by expression in Saccharomyces cerevisiae

Identification of fungal dihydrouracil-oxidase genes by expression in Saccharomyces cerevisiae

α-Tocopherol phosphate as a photosensitizer in the reaction of nucleosides with UV light: formation of 5,6-dihydrothymidine

Identification of fungal dihydrouracil-oxidase genes by expression in Saccharomyces cerevisiae

Contact Info

Product

Resources

About