Role of glucose repression in the oxidative stress response ofSchizosaccharomyces pombe: analysis of transcript levels of fbp1, hxk2, sod1and ctt1 genes in sty1, atf1 and pap1 knock-out mutants


Abstract: Previously we reported that the glucose sensing/signaling pathway affected the oxidative stress response of Schizosaccharomyces pombe, based on studies of glucose-repression and oxidative-stress-resistant mutants including ird5. sty1, encoding a protein kinase, and aft1 and pap1, encoding transcription factors, are important components of the oxidative stress response in S. Pombe. To analyze the relationship between the glucose sensing/signaling pathway and the oxidative stress response, we generated sty1, aft1, and pap1 knock-out mutants in ird5 and wild-type backgrounds. We evaluated the survival rates of the ird5 double mutants (5A, 5P, and 5S) and wild-type single mutants (9A, 9P, and 9S) under mild oxidative stress. In addition, we analyzed the transcript levels of genes related to oxidative stress (sod1, encoding superoxide dismutase; ctt1, encoding catalase) and glucose metabolism (fbp1, encoding fructose-1, 6-bisphosphatase; hxk2, encoding hexokinase). All deletion mutants showed very low survival rates under oxidative stress (<7%). It was shown that transcript levels of sod1 drastically increased in single mutants, while those of ctt1 slightly increased in double mutants. Our results indicate that these mutants are highly sensitive to oxidative stress, and that atf1, pap1, and sty1, as well as sod1 and ctt1, are very important in the oxidative stress response of S. Pombe.

Keywords: Oxidative stress response, glucose repression, Atf1, Pap1, Sty1, knock-out deletion, Schizosacharomyces pombe

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