Project description:In response to carbon source switching from glucose to non-glucose, such as ethanol and galactose, yeast cells can directionally preprogram cellular metabolism to efficiently utilize the nutrients. However, the understanding of cellular responsive network to utilize a non-natural carbon source, such as xylose, is limited due to the incomplete knowledge on the xylose response mechanisms. Here, through optimization of the xylose assimilation pathway together with combinational evaluation of reported targets, we generated a series of mutants with varied growth ability. However, understanding how cells respond to xylose and remodel cellular metabolic network is far insufficient based on current information. Therefore, genome-scale transcriptional analysis was performed to unravel the cellular reprograming mechanisms underlying the improved growth phenotype.
Project description:We propose a carbon source dependent genetic regulatory network for the budding yeast Saccharomyces cerevisiae, derived from quantitative proteomic analyses integrated with bioinformatics knowledge of regulatory pathways and protein interactions. The proposed network, comprising 1247 transcription factor interactions and 126 chaperone interactions, defines the proteome shift in the cell when growing under different carbon sources. We used a label-free proteomics strategy to quantify alterations in protein abundance for S. cerevisiae when grown on minimal media using glucose, galactose, maltose and trehalose as sole carbon sources.
Project description:In the present study transcriptome and proteome of recombinant, xylose-utilising S. cerevisiae grown in aerobic batch cultures on xylose were compared with glucose-grown cells both in glucose repressed and derepressed states. The aim was to study at genome-wide level how signalling and carbon catabolite repression differed in cells grown on either glucose or xylose. The more detailed knowledge about is xylose sensed as a fermentable carbon source, capable of catabolite repression like glucose, or is it rather recognised as a non-fermentable carbon source is important in achieving understanding for further engineering this yeast for more efficient anaerobic fermentation of xylose.
