Metabolic Changes Induced by Deletion of Transcriptional Regulator in Xylose-Fermenting .

Glucose repression has been extensively studied in , including the regulatory systems responsible for efficient catabolism of glucose, the preferred carbon source. However, how these regulatory systems would alter central metabolism if new foreign pathways are introduced is unknown, and the regulatory networks between glycolysis and the pentose phosphate pathway, the two major pathways in central carbon metabolism, have not been systematically investigated. Here we disrupted , a key transcriptional regulator, in strain SR7 engineered to heterologously express the xylose-assimilating pathway, activating genes involved in glycolysis, and evaluated the global metabolic changes. deletion reduced cellular growth in glucose but significantly increased growth when xylose was the sole carbon source. Global metabolite profiling revealed differential regulation of yeast metabolism in SR7-, especially carbohydrate and nucleotide metabolism, depending on the carbon source. In glucose, the SR7- mutant showed overall decreased abundance of metabolites, such as pyruvate and sedoheptulose-7-phosphate, associated with central carbon metabolism including glycolysis and the pentose phosphate pathway. However, SR7- showed an increase in metabolites abundance (ribulose-5-phosphate, sedoheptulose-7-phosphate, and erythrose-4-phosphate) notably from the pentose phosphate pathway, as well as alteration in global metabolism when compared to SR7. These results provide insights into how the regulatory system coordinates the transcription of glycolytic genes and associated metabolic pathways.