GABA induction of the Saccharomyces cerevisiae UGA4 gene depends on the quality of the carbon source

RIOS CRISTIAN DAMIAN; CAROLINA EDITH LEVI; CARDILLO SABRINA BEATRIZ; TRAVO ADRIAN; FORFAR ISABELLE; DELERIS GERARD; CORREA GARCIA SUSANA; BERMUDEZ MORETTI MARIANA

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The quality of the carbon source modulates the expression of UGA4 gene that encodes a permease capable of transporting γ-aminobutyric acid into the cells. In the presence of a fermentable carbon source, UGA4 expression is induced by GABA while in the presence of a non-fermentable carbon source this expression is GABA-independent. The aim of this work was to study the mechanisms responsible for the differences in the profiles of UGA4 expression in both growth conditions. We found that the activity of the main transcription factors responsible for UGA4 induction by GABA varies depending on the quality of the carbon source. In glucose, the negative GATA factor Dal80 binds to UGA4 promoter; only after the addition of the inducer, the positive factors Uga3, Dal81 and Gln3 interact with the promoter removing Dal80 leading to gene induction. In contrast, in acetate the negative GATA factor remains bound to UGA4 promoter under all the conditions assayed, the positive factors are not detected bound in any conditions and in consequence, UGA4 is not induced. We also established the participation of Tor1 and Snf1 kinases on UGA4 expression and the subcellular localization of Gln3, a key positive GATA factor in this regulation. Using FT-IR spectroscopy we detected that gene expression changes induced subtle modifications in metabolic profiles.