Current Genetics

, Volume 36, Issue 3, pp 130–136

New insights into the pyrimidine salvage pathway of Saccharomyces cerevisiae: requirement of six genes for cytidine metabolism

  • J. E. Kurtz
  • F. Exinger
  • P. Erbs
  • R. Jund
ORIGINAL PAPER

Abstract

Cytidine metabolism in the yeast Saccharomyces cerevisiae was analyzed by genetic and biochemical approaches. Disruption of a unique ORF (Genbank accession No. U 20865) bearing homology with eucaryotic or bacterial cytidine deaminases abolished cytidine deaminase activity and resulted in 5-fluorocytidine resistance. The gene encoding cytidine deaminase will be referred to as CDD1 (Genbank accession number AF080089). The ability to isolate mutants resistant to 5-fluorocytidine which mapped to five other loci demonstrated the existence of a complex cytidine metabolic network. Deciphering this network revealed several original features:

(1) cytidine entry is mediated by the purine-cytosine transporter (Fcy2p),

(2) cytidine is cleaved into cytosine by the uridine nucleosidase (Urh1p),

(3) cytidine is phosphorylated into CMP by the uridine kinase (Urk1p),

(4) a block in cytosine deaminase (Fcy1p), but not in cytidine deaminase (Cdd1p), constitutes a limiting step in cytidine utilisation as a UMP precursor.

Key words Pyrimidine salvage pathway Cytidine deaminase Cytidine metabolism CDD1 Uridine/cytidine kinase 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • J. E. Kurtz
    • 1
  • F. Exinger
    • 1
  • P. Erbs
    • 1
  • R. Jund
    • 1
  1. 1.Laboratoire de Génétique, UPR 9003 CNRS, Institut de Recherche contre les Cancers de l'Appareil Digestif, Hôpitaux Universitaires de Strasbourg, 1 Place de l'Hôpital, F-67091 Strasbourg Cedex, France e-mail: Richard.jund@ircad.u-strasbg.fr Fax: +33-3-88 11 90 99FR

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