title: Complementation of areA- regulatory gene mutations of Aspergillus nidulans by the heterologous regulatory gene nit-2 of Neurospora crassa.
abstract: Loss-of-function mutations in the regulatory gene areA of Aspergillus nidulans prevent the utilization of a wide variety of nitrogen sources. The phenotypes of nit-2 mutants of Neurospora crassa suggest that this gene may be analogous to the areA gene. Transformation has been used to introduce a plasmid containing the nit-2 gene into A. nidulans. The nit-2 gene of Neurospora complemented mutations in the areA gene, restoring the ability to use a variety of nitrogen sources. This indicated that the activator function of nit-2 and areA gene products was retained across these two fungal species. Southern blot analysis revealed both single-copy and multicopy integrations and, in at least one case, integration appeared to generate a nit-2 mutation. Integration of the transforming plasmid appeared to be by nonhomologous events at a number of different sites in the Aspergillus genome. The transformants were less sensitive to nitrogen-metabolite repression of extracellular protease activity and nitrate reductase (EC 1.6.6.3) than were wild-type A. nidulans. This indicated that nitrogen control was not completely normal in the nit-2 transformants.
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics*; D005796:Genes; D005800:Genes, Fungal; D005809:Genes, Regulator; D005816:Genetic Complementation Test; D009154:Mutation; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000235:genetics*; D009565:Nitrate Reductases / Q000235:genetics / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism
chemical_list: D009565:Nitrate Reductases; D009584:Nitrogen