Unravelling the transcriptional regulation of Saccharomyces cerevisiae UGA genes: the dual role of transcription factor Leu3.

CORREA GARCIA SUSANA; CORREA GARCIA SUSANA; PALAVECINO MARCOS; PALAVECINO MARCOS; BERMUDEZ MORETTI MARIANA; BERMUDEZ MORETTI MARIANA

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Lugar: London; Año: 2017 vol. 163 p. 1692 - 1701

1350-0872

Yeast cells can use the -aminobutyric acid (GABA) as a nitrogen source. UGA4, UGA1 and UGA2 are the genes involved in GABA catabolism. They are inducible by GABA and subject to nitrogen catabolite repression. Hence, their regulation occurs through two mechanisms, one dependent on the inducer and the other one on the nitrogen source quality. The aim of this work was to go deep in the molecular mechanisms of transcription factors acting on different regulatory elements present in UGA promoters such as Uga3, Dal81, Leu3 and the GATA factors and to find new evidence of a concerted action between them. We found that Gat1 plays an important role in GABA induction of UGA4 transcription, that Dal80 is responsible for UGA4 repression in the absence of GABA and that Gzf3 has an effect in cells grown in a poor nitrogen source and that this effect is positive on UGA4 expression probably due to the modulation of Gat1 activity. Moreover our results indicated that the repressing activity of Leu3 on UGA4 and UGA1 occurs through Dal80 since we clearly demonstrated that Leu3 facilitates Dal80 interaction with DNA. However, in the absence of the GATA factors, Leu3 functions as an activator.