Nitrogen metabolite signalling in Aspergillus nidulans is subject to regulation by the GATA transcription factor AREA, the activity of which is determined by the quality and quantity of the available nitrogen sources. Under conditions of nitrogen limitation, AreA activity increases and this results in the expression of a large, though as yet undefined, number of genes. Here we report that proteomic based analysis of nitrogen signalling revealed differential expression of three genes. The expression of AN3674.2 increased significantly within 2 minutes of adding Gln. The predicted AN3674.2 protein shows homology to domain of Pleckstrin which binds phosphoinositidies and involved in targeting proteins to the plasma membrane. A second gene, AN6921.2, appeared in two forms with different molecular weight. Under conditions of nitrogen limitation the lower molecular weight form predominates while the opposite occurs under derepressed conditions. The predicted protein displays homology to the yeast SGT protein which is involved in assembling of the SCF ubiquitin ligase. The third gene is only expressed in the presence of Gln is AN0084.2 and shows homology to the Ran-binding domain (RdnBP1). This regulates receptor-mediated transport of RNA and proteins between nucleus and cytoplasm. The implication of these proteins in nitrogen metabolite signalling pathway will be discussed.
Full conference title:
157th Meeting of the Society of General Microbiology
- SGM 157th (2005)