Article

Genes involved in glucose repression and oxidative stress response in the fission yeast Schizosaccharomyces pombe.

Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Istanbul, Turkey.
Genetics and molecular research: GMR (Impact Factor: 0.99). 11/2011; 10(4):4041-7. DOI: 10.4238/2011.November.8.4
Source: PubMed

ABSTRACT We looked for changes in gene expression and novel genes that could be involved in the interaction between glucose repression and oxidative stress response in the fission yeast, Schizosaccharomyces pombe, using a constitutive invertase mutant, ird11, which is resistant to glucose. BLAST analysis was made of the S. pombe genome database of cDNAs whose expression ratios differentially decreased or increased upon exposure to mild oxidative stress in this mutant compared to the wild type. Genes with this type of activity were identified as rpl302, encoding 60S ribosomal protein L3, and mpg1, encoding mannose-1-phosphate guanyltransferase; their expression patterns were measured using quantitative real-time PCR. We found that the expression levels of rpl302 and mpg1 genes in ird11 under unstressed conditions were increased compared to those of the wild type. Under stress conditions, the expression levels of the rpl302 gene were decreased in both strains, while mpg1 expression levels remained unchanged. These results suggest that these genes play a role in the response to oxidative stress in this mutant strain.

0 Bookmarks
 · 
98 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The present study analyzed whether or not the in vitro cultivation for long periods of time of pre-isolated Leishmania amazonensis from lesions of chronically infected BALB/c mice was able to interfere in the parasites' infectivity using in vivo and in vitro experiments. In addition, the proteins that presented a significant decrease or increase in their protein expression content were identified applying a proteomic approach. Parasites were cultured in vitro for 150 days. Aliquots were collected on the day 0 of culture (R0), as well as after ten (R10; 50 days of culture), twenty (R20; 100 days of culture), and thirty (R30; 150 days of culture) passages, and were used to analyze the parasites' in vitro and in vivo infectivity, as well as to perform the proteomic approach. Approximately 837, 967, 935, and 872 spots were found in 2-DE gels prepared from R0, R10, R20, and R30 samples, respectively. A total of 37 spots presented a significant decrease in their intensity of expression, whereas a significant increase in protein content during cultivation could be observed for 19 proteins (both cases >2.0 folds). Some of these identified proteins can be described, such as diagnosis and/or vaccine candidates, while others are involved in the infectivity of Leishmania. It is interesting to note that six proteins, considered hypothetical in Leishmania, showed a significant decrease in their expression and were also identified. The present study contributes to the understanding that the cultivation of parasites over long periods of time may well be related to the possible loss of infectivity of L. amazonensis. The identified proteins that presented a significant decrease in their expression during cultivation, including the hypothetical, may also be related to this loss of parasites' infectivity, and applied in future studies, including vaccine candidates and/or immunotherapeutic targets against leishmaniasis.
    PLoS Neglected Tropical Diseases 04/2014; 8(4):e2764. · 4.57 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The yeast Saccharomyces cerevisiae was metabolically modified for enhanced biofuel precursor production by knocking out genes encoding mitochondrial isocitrate dehydrogenase and over-expression of a heterologous ATP-citrate lyase. A comparative iTRAQ-coupled 2D LC-MS/MS analysis was performed to obtain a global overview of ubiquitous protein expression changes in S. cerevisiae engineered strains. More than 300 proteins were identified. Among these proteins, 37 were found differentially expressed in engineered strains and they were classified into specific categories based on their enzyme functions. Most of the proteins involved in glycolytic and pyruvate branch-point pathways were found to be up-regulated and the proteins involved in respiration and glyoxylate pathway were however found to be down-regulated in engineered strains. Moreover, the metabolic modification of S. cerevisiae cells resulted in a number of up-regulated proteins involved in stress response and differentially expressed proteins involved in amino acid metabolism and protein biosynthesis pathways. These LC-MS/MS based proteomics analysis results not only offered extensive information in identifying potential protein-protein interactions, signal pathways and ubiquitous cellular changes elicited by the engineered pathways, but also provided a meaningful biological information platform serving further modification of yeast cells for enhanced biofuel production.
    PLoS ONE 01/2013; 8(12):e84661. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The relationship between glucose repression and the oxidative stress response was investigated in Schizosaccharomyces pombe wild type cells (972h-) and glucose repression resistant mutant type cells (ird11). We aimed to reveal the mechanism of simultaneous resistance to glucose repression and oxidative stress in ird11 mutants. Compared to the wild type, the expression of the sty1 gene was not altered in the ird11 mutant under normal growth conditions, but decreased after exposure to H2O2. This effect was clearly explained by the immunoblotting results, which showed elevated levels of a much more stable phosphorylated form of Sty1 mitogen-activated protein kinase in the ird11 mutant. Increased ght3 gene expression levels were also found, which may play a role in protecting the ird11 mutant from the deleterious effects of oxidative stress. In addition, decreased expression levels of glycolytic enzyme enolase- and thiamine synthesis/transport-related genes were detected. This might have resulted from the flux redirection toward mitochondrial respiration, which would enhance NADPH generation to prevent the high reactive oxygen species accumulation that is generated by respiration. Some evidence supported a flux shift toward fermentation as well as respiration. We conclude that a defect in the glucose-sensing signaling pathway in ird11 mutants likely causes erroneous low glucose-sensing signaling and high ATP production. This most likely occurs because high glucose availability in the medium induces an impairment in the respiratory chain and fermentation balance in these cells, which might explain the glucose repression and oxidative stress resistance in ird11 compared to the wild type.
    Genetics and molecular research: GMR 07/2014; 13(3):5582-5593. · 0.99 Impact Factor

Full-text

View
2 Downloads
Available from