Transcriptomic comparison of Aspergillus niger growing on two different sugars reveals coordinated regulation of the secretory pathway.

摘要: The filamentous fungus, Aspergillus niger, responds to nutrient availability by modulating secretion of various substrate degrading hydrolases. This ability has made it an important organism in industrial production secreted glycoproteins. recent publication the A. niger genome sequence and microarrays allow high resolution studies transcriptional regulation basal cellular processes, like those glycoprotein synthesis secretion. It is known that activities certain secretory pathway enzymes involved N-glycosylation are elevated response carbon source induced glucoamylase. We have investigated whether dependent enhancement protein can lead upregulation elements extending beyond N-glycosylation. study compares physiology transcriptome growing at same specific growth rate (0.16 h-1) on xylose or maltose carbon-limited chemostat cultures. Transcription profiles were obtained using Affymetrix GeneChip analysis six replicate cultures for each two growth-limiting sources. extracellular proteins per gram dry mycelium was about three times higher compared xylose. defined culture conditions resulted reproducibility, discriminating even low-fold differences transcription, which characteristic genes encoding functions. included central metabolic pathways. Increased accompanied transcription > 90 related upregulated encode key translocation endoplasmic reticulum (ER), folding, N-glycosylation, quality control, vesicle packaging transport between ER Golgi. induction effect resembles unfolded (UPR), results from ER-stress previously been treatment with chemicals interfering folding glycoproteins expression heterologous proteins. show also occurs inducing endogenous – representing a more normal physiological state. Transcriptional may thus reflect general mechanism modulation capacity conditional need enzymes.