The Analysis of the growth conditions transcription and frameshift rate of Ty2 retrotransposon

Thesis Type: Postgraduate

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

Approval Date: 2003

Thesis Language: Turkish


Supervisor: Sezai Türkel


Ty2 retrotransposon of S.cerevisiae is one of the fîve families of Ty LTR eiements found in the yeast genome. They transpose by way of RNA intermediates from one location to the another in the yeast genome. Ty2 retrotransposon has a highly saturated promoter structure containing many regulatory eiements giving it the ability o f buffering the intracellular metabolic fluctuations at the transcription level. Therefore the environmental conditions in which S.cerevisae cells grow have a significant role in the transcriptional regulation of Ty2 retroelement. Ty2 retroelement has TYA and TYB genes homologous to retroviral GAG and POL genes. The POL homolog of Ty2, TYB is synthesized in the form of TYA::TYB ftısion peptide by a mechanism called Translational Frameshift during the translation. Frameshift event occurs at % 26 of times during translation and that Frameshift rate is very cnıcial for the Life o f Ty2 retrotransposon. Any deviation from this rate affects the life cycle o f Ty2 negabvely. In this research, the alterations in the transcription and frameshift rate of Ty2 element were investigated with respect to the growth stages and the changes of carbon source. Apart from that, the levels of Frameshift rate and transcription of Ty2 element were examined in torik, sip-4k and cat-8k mutant strains in response to carbon source changes. Transcription and frameshift rate were seen to show paralel pattems relative to the Growth curve except for the stationary phase. İh the mutants o f sip-4k and cat-8k , while no dramatic alteration was observed in response to the changes in the carbon source, when compared with the wild type. In to rik mutant, frameshift rate was detected to stay % 50 less than it was seen in the wild type, when shifted to non-fermentable carbon source.