In A. nidulans arginine is utilised as a nitrogen and carbon source and it is a good system for investigation the connection between the two global carbon and nitrogen repression regulatory systems. Utilization of arginine depends on the presence and inducibility of two arginine catabolic enzymes arginase and ornithine aminotransferase (OAT) encoded by agaA and otaA genes, respectively. Analysis of different single and double areA and areB mutants have shown that two GATA factors AREA and AREB negatively regulate the expression of arginine catabolism genes under nitrogen repression conditions. AREA and AREB activities depend on carbon source. AREA regulator is necessary for the ammonium repression of arginine catabolism genes under carbon repressing conditions while AREB - under carbon limited, non-repressing conditions. AREA activity was shown to be modulated by a direct protein protein interaction with NMRA protein which is proposed to bind to the C terminus of AREA and repress its activity in the presence of glutamine (Platt et al., 1996; Andrianopoulos et al., 1998; Lamb 2003 et al., Lamb et al., 2004; W ong et al., 2007). W e have shown that these interactions are also important in nitrogen metabolite repression of arginine catabolism genes.
Full conference title:
7th International Aspergillus Meeting
- Asperfest 7 (2010)