This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Neuhard, J. Search for Related Content PubMed PubMed Citation Articles by Neuhard, J.

 Previous Article  |  Next Article 

J Bacteriol. 1968 November; 96(5): 1519-1527
Copyright © 1968 American Society for Microbiology. All Rights Reserved.

Pyrimidine Nucleotide Metabolism and Pathways of Thymidine Triphosphate Biosynthesis in Salmonella typhimurium

Institute of Biological Chemistry, University of Copenhagen, Øster Farimagsgade 2A, Copenhagen K, Denmark

ABSTRACT

The nucleoside triphosphate pools of two cytidine auxotrophic mutants of Salmonella typhimurium LT-2 were studied under different conditions of pyrimidine starvation. Both mutants, DP-45 and DP-55, are defective in cytidine deaminase and cytidine triphosphate (CTP) synthase. In addition, DP-55 has a requirement for uracil (uridine). Cytidine starvation of the mutants results in accumulation of high concentrations of uridine triphosphate (UTP) in the cells, while the pools of CTP and deoxy-CTP drop to undetectable levels within a few minutes. Addition of deoxycytidine to such cells does not restore the dCTP pool, indicating that S. typhimurium has no deoxycytidine kinase. From the kinetics of UTP accumulation during cytidine starvation, it is concluded that only cytidine nucleotides participate in the feedback regulation of de novo synthesis of UTP; both uridine and cytidine nucleotides participate in the regulation of UTP synthesis from exogenously supplied uracil or uridine. Uracil starvation of DP-55 in presence of cytidine results in extensive accumulation of CTP, suggesting that CTP does not regulate its own synthesis from exogenous cytidine. Analysis of the thymidine triphosphate (dTTP) pool of DP-55 labeled for several generations with ³²P-orthophosphate and ³H-uracil in presence of ¹²C-cytidine shows that only 20% of the dTTP pool is derived from uracil (via the methylation of deoxyuridine monophosphate); 80% is apparently synthesized from a cytidine nucleotide.

This article has been cited by other articles:

• Dickerson, S. K., Market, E., Besmer, E., Papavasiliou, F. N. (2003). AID Mediates Hypermutation by Deaminating Single Stranded DNA. J. Exp. Med. 197: 1291-1296 [Abstract] [Full Text]  
• Dance, G. S. C., Beemiller, P., Yang, Y., Mater, D. V., Mian, I. S., Smith, H. C. (2001). Identification of the yeast cytidine deaminase CDD1 as an orphan C{->}U RNA editase. Nucleic Acids Res 29: 1772-1780 [Abstract] [Full Text]  
• Papavasiliou, F. N., Schatz, D. G. (2002). The Activation-induced Deaminase Functions in a Postcleavage Step of the Somatic Hypermutation Process. J. Exp. Med. 195: 1193-1198 [Abstract] [Full Text]