Trehalose and glycogen metabolism of gcr1 mutants of saccharomyces cerevisiae

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2002
Şeker, Tamay
S. cerevisiae is one of the most important microorganisms with respect to its long history and being model organism. Trehalose and glycogen are the major carbohydrate stores in yeast cell and they are typically hall-marks of rapid adaptations of yeast cells to environmental changing conditions such that trehalose has a significant role in preservation and survival of the yeast cells under adverse conditions, while glycogen is the main energy source. Trehalose metabolism has also a regulatory role in glucose uptake. GCR1 encodes a DNA binding protein and regulates the transciption of the glycolytic genes and the levels of most of the glycolytic enzymes are reduced 111to 5- 10 % of the wild type in gcrl cells resulting in growth deficiency. In this study, the response of gcrl yeast cells to the glucose pulse was questioned with respect to the change in trehalose and glycogen levels. The initial trehalose levels were determined as similar both in wild type and gcrl cells at the beginning of the exponential phase, whereas, wild type has two times glycogen of the mutant yeast cell. A fast accumulation in the 1st and 2nd hours which is followed by a steady decrease reaching to stable low levels seems to be the same phenomenon for both glycogen and trehalose levels in gcrl and wild type yeast cells in response to a glucose pulse. Both trehalose and glycogen accumulation are higher in the gcrl cells compared to the wild type, but the following decreasing period is higher in the wild type inversely. This observation is adaptable to the proposed phenotype for gcrl cells and in summary we have an idea of that the components of trehalose and glycogen metabolisms may not be affected with GCR1 mutation and both of gcrl cells and wild type yeast cells may have similar glucose repression mechanisms.
Citation Formats
T. Şeker, “Trehalose and glycogen metabolism of gcr1 mutants of saccharomyces cerevisiae,” Ph.D. - Doctoral Program, Middle East Technical University, 2002.