Molecular analysis of the translational control mechanisms in the EST3 gene


Thesis Type: Postgraduate

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

Approval Date: 2015

Thesis Language: Turkish

Student: SALİHA ELİF YILDIZHAN

Supervisor: Sezai Türkel

Abstract:

The expression of the EST3 gene, which encodes the regulatory subunit of telomerase, is regulated by a programmed ribosomal frameshifting mechanism at the translation level. The full length Est3p is synthesized by +1 ribosomal frameshift. In the absence of the programmed ribosomal frameshift, the translation of the EST3 mRNA is terminated at an internal stop codon and a truncated Est3 peptide with no known functions is produced. In this study, it has been shown that frameshifting efficiency in the EST3 gene varies in S. cerevisiae according to the carbon source in which the cells are grown. When the frameshift efficiency in wild type cells grown in high glucose concentration was compared to that in cells grown in low glucose concentration and that in cells grown in the alternative carbon source glycerol lactate, it was found to be higher by 2-fold and 10-fold respectively. It was shown that in Δsnf1 mutants, the carbon source effect is lost, which supports that the carbon source effect is controlled by glucose signaling. It was shown that in Δasc1 ve Δstm1 mutants, frameshift rates were lower than those in wild type cells and that the Asc1 and Stm1 proteins play a role in EST3 programmed frameshifting.