Ammonia Regulates VID30 Expression and Vid30p Function Shifts Nitrogen Metabolism toward Glutamate Formation Especially when Saccharomyces cerevisiae Is Grown in Low Concentrations of Ammonia

Abstract

The GATA family proteins Gln3p and Gat1p mediate nitrogen catabolite repression (NCR)-sensitive transcription in Saccharomyces cerevisiae. When cells are cultured with a good nitrogen source (glutamine, ammonia), Gln3p and Gat1p are restricted to the cytoplasm, whereas with a poor nitrogen source (proline), they localize to the nucleus, bind to the GATA sequences of NCR-sensitive gene promoters, and activate transcription. The target of rapamycin-signaling cascade and Ure2p participate in regulating the cellular localization of Gln3p and Gat1p. Rapamycin, a Tor protein inhibitor, like growth with a poor nitrogen source, promotes nuclear localization of Gln3p and Gat1p. gln3⌬ and ure2⌬ mutants are partially resistant and hypersensitive to growth inhibition by rapamycin, respectively. We show that a vid30⌬ is more rapamycin-sensitive than wild type but less so than a ure2⌬. VID30 expression is modestly NCR-sensitive, responsive to deletion of URE2, and greatly increases in low ammonia medium. Patterns of gene expression in a vid30⌬ suggest that the Vid30p function shifts the balance of nitrogen metabolism toward the production of glutamate, especially when cells are grown in low ammonia. CAN1, DAL4, DAL5, MEP2, DAL1, DAL80, and GDH3 transcription is down-regulated by Vid30p function with proline as the nitrogen source. An effect, however, that could easily be indirect.

The Genome-wide Transcriptional Responses of Saccharomyces cerevisiae Grown on Glucose in Aerobic Chemostat Cultures Limited for Carbon, Nitrogen, Phosphorus, or Sulfur

“…trace element or vitamin growth limitations) and selecting the specifically regulated gene sets. Improvement on the issue raised by the second possibility is, however, more complicated, as shown by a study of the DAL1/DAL4 promoter that showed active promoter elements were extremely difficult to predictably identify (18). The promoter analysis data presented here therefore holds its greatest value in simply identifying overrepresented sequences to indicate which transcription factors are likely to be active.…”

Expression of human AID in yeast induces mutations in context similar to the context of somatic hypermutation at G-C pairs in immunoglobulin genes

“…Yeast was used in this study to characterize the mutator effects of ectopic expression of human AID. The CAN1 reporter gene has been chosen because of numerous mutational studies [52,54] and a well-characterized transcription pattern [62-64]. The results are different from studies of AID effects in prokaryotic models and in vitro experiments.…”

Deletion of the Aspergillus fumigatus Gene Encoding the Ras-Related Protein RhbA Reduces Virulence in a Model of Invasive Pulmonary Aspergillosis

“…Altered sensitivity to rapamycin is a hallmark phenotype of defective TOR kinase signaling in S. cerevisiae, as evidenced by deletion or mutation of numerous TOR effectors (5,12,17,38). Treatment of S. cerevisiae yeasts with rapamycin leads to rapid release of NCR, whereas the phenotypic consequences of treating the S. pombe yeasts with rapamycin are evident only under nitrogen-limited conditions (39).…”