Functions of PUF Family RNA-Binding Proteins in Aspergillus nidulans

RNA-binding proteins are involved in RNA metabolism and posttranscriptional regulation of various fundamental biological processes. The PUF family of RNA-binding proteins is highly conserved in eukaryotes, and its members regulate gene expression, mitochondrial biogenesis, and RNA processing. However, their biological functions in Aspergillus species remain mostly unknown in filamentous fungi. Here we have characterized the puf genes in the model organism Aspergillus nidulans. We generated deletion mutant strains for the five putative puf genes present in the A. nidulans genome and investigated their developmental phenotypes. Deletion of pufA or pufE affected fungal growth and asexual development. pufA mutants exhibited decreased production of asexual spores and reduced mRNA expression of genes regulating asexual development. The pufE deletion reduced colony growth, increased formation of asexual spores, and delayed production of sexual fruiting bodies. In addition, the absence of pufE reduced both sterigmatocystin production and the mRNA levels of genes in the sterigmatocystin cluster. Finally, pufE deletion mutants showed reduced trehalose production and lower resistance to thermal stress. Overall, these results demonstrate that PufA and PufE play roles in the development and sterigmatocystin metabolism in A. nidulans.