Investigation of Genes Expressıon Involved in Thiamine Biosynthesis in Schizosaccharomyces pombe One of the essential vitamins thiamine active forms TDP (thiamine diphosphate) is known to undertake the task of co-factor for most of the metabolic enzymes (in carbohydrate metabolism as pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and in the pentose phosphate pathway as transketolase). TMP (thiamine monophosphate) is occured by the thiamine-phosphate synthase which combines thiazol and pyrimidine together. Later on, the TMP is converted to active form of TDP. Schizosaccaromyces pombe can obtain thiamine either by biosynthasis on it self or by taking it ready from external sources. Thiamine biosynthesis pathway in this yeast is suppressed by the presence of thiamine.
Within the scope of this thesis, we compared wild type S. pombe and S. pombe ird11 mutant which is resistant to glucose repression and oxidative stress. Again, while comparing genes' (which having roles in biosynthesis of thiamine or transporting of it) expression profiles under conditions of presence of thiamine and non-presence of thiamine, the role of thiamine in oxidative stress was investigated at the same time. In comparing genes' expression profiles, real time polymerase chain reaction (qPCR) technique was used. The expression of genes (bsu1, thi4, thi2, pho1, TENA/THI family protein genes, phosphomethylpyrimidine kinase (predicted) gene, thi3/nmt1) which are responsible for thiamine biosynthesis and transport increased in ird11 (ird11HP) mutants under oxidative condition by comparison to wild type S. pombe. This result showed that thiamine has an important role on the oxidative stress response. In the following studies, revealing the levels and the stages of the interaction of thiamine both with glucose metabolism and with oxidative stress, will light on some blind spots of some important methabolic diseases as diabetes and neurodegenerative ones.
