Identification of sequence determinants of human nuclear dUTPase isoform localization.

dUTP nucleotidohydrolase (dUTPase) catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate and is the central regulator of cellular dUTP pools. Nuclear (DUT-N) and mitochondrial (DUT-M) isoforms of the protein have been identified in humans and arise from the same gene by the alternative use of 5' exons. Recently, it has been shown that these isoforms are aberrantly expressed in some cancers and overexpression of dUTPase in the nucleus is associated with resistance to chemotherapeutic agents that target thymidylate biosynthesis.

hSMUG1 can functionally compensate for Ung1 in the yeast Saccharomyces cerevisiae.

There are at least four distinct families of enzymes that recognize and remove uracil from DNA. Family-3 (SMUG1) enzymes have recently been identified and have a preference for uracil in single-stranded DNA when assayed in vitro. Here we investigate the in vivo function of SMUG1 using the yeast Saccharomyces cerevisiae as a model system.

dUTPase and uracil-DNA glycosylase are central modulators of antifolate toxicity in Saccharomyces cerevisiae.

The thymidylate synthase reaction remains an important target for widely used anticancer agents; however, the clinical utility of these drugs is limited by the occurrence of cellular resistance. Despite the considerable amount of information available regarding mechanisms of drug action, the relative significance of downstream events that result in lethality remains unclear. In this study, we have developed a model system using the budding yeast Saccharomyces cerevisiae to dissect the influence of dUMP misincorporation into DNA as a contributing mechanism of cytotoxicity induced by antifolate agents.