Chapter 6 Pyrimidine Damage and Repair

Pyrimidines are essential to the structure and function of nucleic acids in all organisms. The chemical reactivity of the pyrimidines is therefore a fundamentally important aspect of survival of all organisms. Pyrimidines are subject to endogenous damage through hydrolysis, alkylation and oxidation, and to damage by exogenous environmental molecules. Damage to these important molecules can result in loss of biochemical function and cell toxicity. The damage of pyrimidines in deoxyribonucleic acids (DNA) could have more long-lasting consequences, as many of the pyrimidine lesions are miscoding during DNA replication resulting genetic mutations, and allowing the effects of the damage to be transmitted to future progeny cells. Emerging evidence also suggests that pyrimidines in DNA play a critical role in establishing transcriptional regulation in complex organisms, and that damage to DNA pyrimidines could alter epigenetic programming. Fortunately, repair systems exist in cells that recognize specific damaged structures and facilitate their removal and ultimately DNA repair.