The nadA gene of Aspergillus nidulans, encoding adenine deaminase, is subject to a unique regulatory pattern

• Published in: Fungal genetics and biology Vol. 45; no. 5; pp. 760 - 775
• Main Authors: Oestreicher, Nathalie, Ribard, Carin, Scazzocchio, Claudio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2008; Elsevier
• Subjects: Adenine deaminase; adenosine; Adenosine - metabolism; Aminohydrolases; Aminohydrolases - biosynthesis; Aminohydrolases - genetics; Ammonium induction; ammonium nitrogen; Aspergillus nidulans; Aspergillus nidulans - enzymology; Aspergillus nidulans - genetics; Aspergillus nidulans - growth & development; Aspergillus nidulellus; biochemical pathways; Biochemistry, Molecular Biology; biosynthesis; enzymology; fungal proteins; Fungal Proteins - biosynthesis; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Expression Profiling; gene expression regulation; Gene Expression Regulation, Fungal; genes; genetics; growth & development; Life Sciences; Metabolic Networks and Pathways; metabolism; microbial genetics; Microbiology and Parasitology; Models, Biological; molecular sequence data; nutrient retention; promoter regions; Protein Binding; Purine catabolism; Purine nucleotide cycle; purines; Quaternary Ammonium Compounds; Quaternary Ammonium Compounds - metabolism; synergism; Trans-Activators; Trans-Activators - metabolism; transcription factors; Transcription Factors - metabolism; Transcriptional regulation; uric acid; Uric Acid - metabolism; Adenine deaminase; Purine nucleotide cycle; Transcriptional regulation; Aspergillus nidulans; Purine catabolism; Ammonium induction
• ISSN: 1087-1845; 1096-0937; 1096-0937
• DOI: 10.1016/j.fgb.2007.10.015

The adenine deaminase of A. nidulans, encoded by nadA, can be considered both as a catabolic and a purine salvage enzyme. We show that its transcriptional regulation reflects this double metabolic role. As all other genes involved in purine utilisation it is induced by uric acid, and this induction is mediated by the UaY transcription factor. However, it is also independently and synergistically induced by adenosine by a UaY-independent mechanism. At variance with all other enzymes of purine catabolism it is not repressed but induced by ammonium. This is at least partly due to the ammonium responsive GATA factor, AreA, acting in the nadA promoter as a competitor rather than in synergy with UaY. The adB gene, encoding adenylo-succinate synthetase, which can be considered both a biosynthetic and a salvage pathway enzyme, shares with nadA both ammonium and adenosine induction.