In this study, we adapted the well known uracil DNA glycosylase (UNG) carry-over prevention system for PCR, and applied it to the analysis of DNA methylation based on sodium bisulfite conversion. As sodium bisulfite treatment converts unmethylated cytosine bases into uracil residues, bisulfite treated DNA is sensitive to UNG treatment. Therefore, UNG cannot be used for carry-over prevention of ...

The rate of nitrous acid deamination of labeled cytosine residues in native Escherichia coli deoxyribonucleic acid was monitored in vitro by release of acid-soluble counts after treatment with uracil deoxyribonucleic acid glycosylase. The reaction exhibited a lag and was not stimulate by several agents previously shown to enhance base substitution mutagenesis during nitrous acid treatment of du...

Vol.13, No.1 | 2015 | hypothesisjournal.com ABSTRACT Experimental conditions were devised, imitating prebiotic conditions in hydrothermal vents, to examine the possible prebiotic role of free purine bases in the direct synthesis of amino acids. Hypoxanthine, the biochemical precursor of adenine and guanine, was able to capture nitrite ions and be reductively transformed into adenine. Transfer o...

Knowledge of the mechanisms involved in pyrimidine metabolism is fundamental to the biochemistry of the nucleic acids. Cerecedo, Emerson, and Stekol (l-7) pioneered this field in their work with dogs. Their experiments, conducted by feeding the in vitro oxidation products of uracil and the estimation of excreted urea, culminated in the proposal of a mechanism for pyrimidine metabolism (8). More...

Methoxyamine reacts selectively with tRNA molecules at certain exposed cytosine residues usually located in non base-paired regions of the two dimensional clover leaf structure. Here methoxyamine is used for the first time in a study of a mammalian tRNA structure. One of the sequence abnormalities of myeloma initiator tRNA is a cytosine instead of the usual uracil immediately preceding the anti...

We report a systematic solid-state (17)O NMR study of free nucleic acid bases: thymine (T), uracil (U), cytosine (C), and guanine (G). Site-specifically (17)O-enriched samples were synthesized:[2-(17)O]thymine (1), [4-(17)O]thymine (2), [2-(17)O]uracil (3), [4-(17)O]uracil (4), [2-(17)O]cytosine (5), and [6-(17)O]guanine monohydrate (6). Magic-angle-spinning (MAS) and static (17)O NMR spectra w...

Class switch recombination, gene conversion, and somatic hypermutation that diversify rearranged Ig genes to produce various classes of high affinity Abs are dependent on the enzyme activation-induced cytosine deaminase (AID). Evidence suggests that somatic hypermutation is due to error-prone DNA repair that is initiated by AID-mediated deamination of cytosine in DNA, whereas the mechanism by w...

In marsupial mitochondria, the nucleotide residue at the second position of the anticodon of the tRNA for aspartic acid is changed post-transcriptionally such that the translational machinery recognizes it as a uracil rather than the cytosine residue encoded in the gene. By postlabeling nucleotide analysis, we show here that the cytosine residue is converted to a conventional uracil residue in ...