Komponenten des Stickstoffregulations-Netzwerkes in Fusarium fujikuroi

Grunddaten zu diesem Projekt

Beschreibung

The fungus Fusarium fujikuroi is known as producer of gibberellins (GAs) and the red pigment bikaverin. We have cloned the GA-and bikaverin pathway genes (gene clusters) and investigated the regulation of their expression. The expression of both, the GA and bikaverin genes, are under control of nitrogen metabolite repression. We have shown for the first time that the transcription factor AreA which is known to activate pathways for utilization of alternative nitrogen sources, is also important for the expression of GA-and bikaverin pathway genes. Furthermore, we have demonstrated that the TOR (target of rapamycin) kinase is involved in nitrogen regulation by sensing and transduction of the nitrogen signal as it has been shown in S. cerevisiae, though with different modes of action. Preliminary results indicate that the glutamine synthetase (GS) and nitrogen permeases (sensors?) might be key players in the nitrogen regulation network. We want to understand how the fungus senses the nitrogen status of the cell, and by which mechanisms those signals are transduced to AreA. Putative AreA binding partners (e.g. GS?) will be identified by Yeast-2-hybrid (Y2H), and the localization and phosphorylation status of AreA will be analyzed. Furthermore, the potential role of the nitrogen permease reactivator, NPR, for stabilization of ammonium and amino acid permeases and proposed interaction with AreA will be investigated. With this project we want to gain better insight into the molecular mechanisms of the nitrogen metabolite repression in F. fujikuroi by characterization of the mode of action of AreA and interacting partners.