The nadA gene of Aspergillus nidulans, encoding adenine deaminase, is subject to a unique regulatory pattern.
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.
Université Paris XI, CNRS UMR8621, Institut de Génétique et Microbiologie, Bâtiment 409, 91405 Orsay Cedex, France. nathalie.oestreicher@igmors.u-psud.fr
Nathalie
N
Oestreicher
Carin
C
Ribard
Claudio
C
Scazzocchio
D000241:Adenosine / Q000378:metabolism; D000619:Aminohydrolases / Q000096:biosynthesis* / Q000235:genetics; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D011485:Protein Binding; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014527:Uric Acid / Q000378:metabolism
C079728:AreA protein, Aspergillus nidulans; D005656:Fungal Proteins; D000644:Quaternary Ammonium Compounds; D015534:Trans-Activators; D014157:Transcription Factors; C093266:UaY protein, Aspergillus nidulans; D014527:Uric Acid; D000619:Aminohydrolases; C018774:adenine deaminase; D000241:Adenosine