The steady-state levels of uracil residues in DNA extracted from strains of Escherichia coli were measured and the influence of defects in the genes for uracil-DNA glycosylase (ung), double-strand uracil-DNA glycosylase (dug), and dUTP pyrophosphatase (dut) on uracil accumulation was determined. A sensitive method, called the Ung-ARP assay, was developed that utilized E. coli Ung, T4pdg, and th...

Syntheses of cytosine, uracil, and thymine starting from interstellar molecules were examined theoretically. Potential energy surfaces for the formation protonated cytosine (CyH+), uracil (UrH+), (ThH+) cyanoacetylene (HC3N), isocyanic acid (H2NCO+), one NH3, H2O, CH3OH, respectively, determined by quantum chemical calculation using CBS-QB3 method. Barrierless pathways found all three reactions...

Escherichia coli nucleoside diphosphate kinase (Ndk) catalyzes ATP-dependent synthesis of ribo- and deoxyribonucleoside triphosphates from the cognate diphosphate precursor. Recently, the Ndk polypeptide was reported to be a multifunctional base excision repair nuclease that processed uracil residues in DNA by acting sequentially as a uracil-DNA glycosylase inhibitor protein (Ugi)-sensitive ura...

Uracil may arise in DNA as a result of deamination of cytosine or through incorporation of dUMP instead of dTMP during replication. We have studied the steady-state levels of uracil in the DNA of primary cells and mouse embryonic fibroblast (MEF) cell lines from mice deficient in the Ung uracil-DNA glycosylase. The results show that the levels of uracil in the DNA of Ung(-/-) cells strongly dep...

Uracil residues are eliminated from cellular DNA by uracil-DNA glycosylase, which cleaves the N-glycosylic bond between the uracil base and deoxyribose to initiate the uracil-DNA base excision repair pathway. Co-crystal structures of the core catalytic domain of human uracil-DNA glycosylase in complex with uracil-containing DNA suggested that arginine 276 in the highly conserved leucine interca...

Uracil may occur in DNA due to either cytosine deamination or thymine replacing incorporation. Its quantitative characterization is important in assessing DNA damages in cells with perturbed thymidylate metabolism or within different DNA segments involved in immunoglobulin gene diversification. The archaeal DNA polymerase from Pyrococcus furiosus binds strongly to the deaminated base uracil and...

BACKGROUND Five genes--UNG, SMUG1, MBD4, TDG, and DUT--are involved in the repair or prevention of uracil misincorporation into DNA, an anomaly that can cause mutagenic events that lead to cancer. Little is known about the determinants of uracil misincorporation, including the effects of single nucleotide polymorphisms (SNPs) in the abovementioned genes. Because of their metabolic function, fol...

The DNA repair enzyme uracil-DNA glycosylase from Mycoplasma lactucae (831-C4) was purified 1,657-fold by using affinity chromatography and chromatofocusing techniques. The only substrate for the enzyme was DNA that contained uracil residues, and the Km of the enzyme was 1.05 +/- 0.12 microM for dUMP containing DNA. The product of the reaction was uracil, and it acted as a noncompetitive inhibi...

241 Abstract: All known pyrimidine and pyrimidine-derived secondary producs originate from uracil or its precursor, uracil-6-carboxylic acid. The biosynthesis of these products has been suggested to be uracil detoxication mechanisms. The possible toxic effects of uracil on the germination and growh of Pisum sativum L. cultivar Meteor, Lathyrus tingitanus L. in which pyrimidine-derived secondary...

Tegafur-uracil has been reported to have only minor adverse effects and is associated with liver injury in 1.79% of Japanese patients. The development of tegafur-uracil-induced hepatic fibrosis with portal hypertension is rare. Here, we report a case of a 74-year-old woman with rapidly developing tegafur-uracil-induced hepatic fibrosis. The patient had no history of liver disease and had been t...