Regulation of Arginine Metabolism in Saccharomyces cerevisiae: a Network of Specific and Pleiotropic Proteins in Response to Multiple Environmental Signals
Francine Messenguy* and Evelyne Dubois
Institut de Recherches Microbiologiques J. M Wiame, 1, Avenue Emile Gryzon and Laboratoire de Microbiologie de l’Université Libre de Bruxelles, 1070 Brussels, Belgium
Article history:
Received October 11, 2000
Accepted November 29, 2000
Key words:
yeast, arginine metabolism, nitrogen control
Summary:
In Saccharomyces cerevisiae, the expression of the genes involved in the synthesis and degradation of arginine is modulated by multiple specific and pleiotropic factors, acting as repressors or activators as a function of the availability of amino acids, of nitrogen source, and the presence or absence of arginine. Four proteins (Arg80, Arg81, Mcm1 and Arg82) coordinate the expression of arginine metabolic genes, by repressing the biosynthetic genes and by inducing the catabolic genes, in response to arginine. Arg80, Arg81 and Mcm1 form a complex interacting with DNA sequences called »arginine boxes« present in the promoters of arginine co-regulated genes. Binding of arginine to Arg81 allows the interaction of the complex with DNA. The role of Arg82 is to stabilize the Mcm1 and Arg80 proteins. The synthesis of one of the subunits of carbamoylphosphate synthetase encoded by CPA1 gene is also repressed by arginine. However, this results from a translational control involving a 25 amino acid peptide encoded by the messenger of CPA1. Expression of the catabolic genes CAR1 and CAR2 is repressed, as long as exogenous nitrogen is available, by the regulatory complex Ume6-Sin3-Rpd3 exhibiting histone deacetylase activity. Expression of CAR1 but not of CAR2 is activated byGln3 and Nil1 when cells are grown on poor nitrogen sources.
*Corresponding author: 
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