Disruption of MRG19 results in altered nitrogen metabolic status and defective pseudohyphal development in Saccharomyces cerevisiae

Abstract

It was previously shown thatMRG19downregulates carbon metabolism inSaccharomyces cerevisiaeupon glucose exhaustion, and that the gene is glucose repressed. Here, it is shown that glucose repression ofMRG19is overcome upon nitrogen withdrawal, suggesting thatMRG19is a regulator of carbon and nitrogen metabolism.β-Galactosidase activity fostered by the promoter ofGDH1/3, which encode anabolic enzymes of nitrogen metabolism, was altered in anMRG19disruptant. As compared to the wild-type strain, theMRG19disruptant showed a decrease in the ratio of 2-oxoglutarate to glutamate under nitrogen-limited conditions.MRG19disruptants showed reduced pseudohyphal formation and enhanced sporulation, a phenomenon that occurs under conditions of both nitrogen and carbon withdrawal. These studies revealed thatMRG19regulates carbon and nitrogen metabolism, as well as morphogenetic changes, suggesting thatMRG19is a component of the link between the metabolic status of the cell and the corresponding developmental pathway.