Glutamine transport as a possible regulator of nitrogen catabolite repression in Saccharomyces cerevisiae.

Nitrogen catabolite repression (NCR) is a major transcriptional control pathway governing nitrogen use in yeast, with several hundred of target genes identified to date. Early and extensive studies on NCR led to the identification of the 4 GATA zinc finger transcription factors, but the primary mechanism initiating NCR is still unclear up till now. To identify novel players of NCR, we have undertaken a genetic screen in an NCR-relieved gdh1Δ mutant, which led to the identification of four genes directly linked to protein ubiquitylation.