Investigation of the effects of various metal ions on the growth features and transcription of HXT2 gene in Saccharomyces cerevisiae


Thesis Type: Postgraduate

Institution Of The Thesis: Bursa Uludağ University, Fen Bilimleri Enstitüsü, Moleküler Biyoloji ve Genetik, Turkey

Approval Date: 2017

Thesis Language: Turkish

Student: SİNEM ANGIN

Supervisor: Sezai Türkel

Abstract:

Metal ions are required for the various cellular and metabolic activities. Nonetheless, over accumulation of metal ions or transport of toxic metal ions to the cell can inhibit numerous cellular functions, and also can have a cytotoxic and genotoxic effects. Transport of glucose to the cell is carried out by glucose transporter proteins, localized within the cell membrane. Inhibition of glucose transport prevents the biosynthesis of ATP and various cellular metabolites required for the cell metabolism. In this study, the effects of copper, iron, nickel, zinc, magnesium, litium and cadmium on the transcription of HXT2 gene and on the growth features of S. cerevisiae were investigated. Metal ions were added to the growth medium of logarithmically growing yeast cell cultures as soluble compounds at sub-lethal levels. Results of this research indicates that nickel and lithium repress the transcription of HXT2 gene. These metal ions repressed the transcription of HXT2 approximately at 30% under glucose repressed growth conditions. On the contrary, magnesium and iron ions activated the transcription of HXT2 at low levels. Results of this study indicated that stress activated transcription factors Msn2p and Yap1p is not involved in the stress dependent regulation of HXT2 gene. Nonetheless, it was found that the transcriptional regulator Msn2p is required for the basal level expression of HXT2 gene. It was clearly shown that multi-functional protein kinase Snf1p is involved in the metal ion stress dependent regulation of HXT2 gene in S. cerevisiae.