Cloning and functional expression of the mitochondrial alternative oxidase of Aspergillus fumigatus and its induction by oxidative stress

• Published in: FEMS microbiology letters Vol. 271; no. 2; pp. 230 - 238
• Main Authors: Magnani, T., Soriani, F.M., Martins, V.P., Nascimento, A.M., Tudella, V.G., Curti, C., Uyemura, S.A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-2007; Blackwell; Oxford University Press
• Subjects: Acid resistance; Alternative oxidase; Amino Acid Sequence; Aspergillus fumigatus; Aspergillus fumigatus - drug effects; Aspergillus fumigatus - genetics; Aspergillus fumigatus - metabolism; Biological and medical sciences; Blotting, Western; Chain branching; Cloning; Cloning, Molecular; Cyanides - pharmacology; E coli; Electron transport; Electron transport chain; Enzyme Activation - drug effects; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene expression; Gene Expression Regulation, Fungal; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; heterologous expression; Menadione; Microbiology; Mitochondria; Mitochondria - enzymology; Mitochondria - metabolism; Mitochondrial Proteins; Molecular Sequence Data; Mycology; Open reading frames; Oxidase; Oxidation resistance; Oxidative Stress; Oxidoreductases - genetics; Oxidoreductases - metabolism; Oxygen; Oxygen consumption; Oxygen Consumption - drug effects; Oxygen uptake; Paraquat; Paraquat - pharmacology; Plant Proteins; Potassium cyanide; Reactive oxygen species; Reactive Oxygen Species - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Salicylamides - pharmacology; Sequence Homology, Amino Acid; Vitamin K 3 - pharmacology; oxygen uptake; heterologous expression; oxidative stress; alternative oxidase; Oxidative stress; Oxygen; Enzyme; Oxidase; Uptake; Fungi; Mitochondria; Fungi Imperfecti; Oxidoreductases; Aspergillus fumigatus; Thallophyta
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2007.00716.x

Abstract
Aspergillus fumigatus possesses a branched mitochondrial electron transport chain, with both cyanide-sensitive and -insensitive oxygen-consumption activities. Mitochondrial reactive oxygen species mediate signaling for alternative oxidase (AOX) expression. A 1173 bp-long Afaox gene encoding a 40 kDa protein has been cloned and identified. Recombinant constructs containing the Afaox ORF were transformed into Escherichia coli and Saccharomyces cerevisiae for heterologous expression. In A. fumigatus, AOX activity and mRNA expression were both induced with menadione or paraquat, suggesting an important role of AOX under oxidative stress. Therefore, positive transformants showed a cyanide-resistant and salicylhydroxamic acid-sensitive respiration, whereas in control cells the oxygen uptake was completely inhibited after KCN addition.