The MeaB bZIP transcription factor is needed for proper nitrosative stress response induced by nitrite in Aspergillus fumigatus

ABSTRACT: The function of the Aspergillus fumigatus MeaB bZIP-type transcription factor was investigated using a transcriptomics-based approach. Deletion of the meaB gene increased nitrite and menadione-sodium bisulfite, but not terc-butyl hydroperoxide or H2O2 stress sensitivity. When the transcriptome of the DmeaB strain was compared with the wild-type strain (Af293), genes involved in siderophore biosynthesis or glucanases were enriched in the up-regulated gene set, whereas genes encoding heme-binding proteins or chitinases were enriched in the down-regulated gene set. The 90 mM NaNO2-induced stress elicited a response in the DmeaB gene deletion mutant that was very similar to that of the wild-type strain in the presence of 135 mM NaNO2. These stress responses included downregulation of mitotic cell cycle, and ribosomal protein genes, upregulation of nitrosative stress response (fhpA, fhpB, gnoA), nitrate utilization (niaD, niiA), several iron acquisition, ergosterol biosynthesis genes and the alternative oxidase gene aoxA, and altered the transcriptional activity of the secondary metabolite cluster and CAZyme genes. Nitrite treatment upregulated arginine metabolism genes only in the wild-type strain. The observed transcriptional changes were associated with reduced growth, increased redox imbalance and increased sterol content in both strains. Here, we discuss our hypothesis that MeaB affects (endogenous) NO production through fine-tuned regulation of arginine metabolism genes, and that disrupted NO homeostasis was responsible for the altered phenotype of the meaB mutant.

ORGANISM(S): Aspergillus fumigatus

PROVIDER: GSE277801 | GEO | 2024/12/09

REPOSITORIES: GEO