Studies on the control of pyrimidine biosynthesis in human diploid cell strains, I. Effect of 6-azauridine on cellular phenotype.

Abstract

Human diploid cell strains grown in a medium containing 6-azauridine develop augmented levels of both orotidine-5[image]-monophosphate (OMP) pyrophosphorylase and OMP decarboxylase. A cell strain from a patient whose genotype caused a deficiency of these 2 activities developed near normal levels when grown in 6-azauridine. The augmented activity is due to increased enzyme within the cell. The mechanism of augmentation is probably not associated with the incorporation of an azapyrimidine into cellular nucleic acid. It also seems unlikely that the mechanism involves depletion of the cellular pool of pyrimidine nucleotides, though this possibility is difficult to rule out.