The Effect of Tec1 Transcription Factor on NTH1 Gene Expression

Yıl 2019, , 620 - 627, 31.08.2019

Tulay Turgut Genc , Selen Çakas

https://doi.org/10.18185/erzifbed.457862

Öz

The intracellular accumulation of trehalose is one of the physiological response of yeast cells to different environmental stresses. The amount of trehalose in the cell changes during the phases of cell cycle and affects the chronological life span of Saccharomyces cerevisiae yeast cells. The expression of the NTH1 gene, which encodes the neutral trehalase enzyme responsible from the stress-accumulated trehalose breakdown, is controlled through different signaling pathways. TOR signaling system, one of these pathways, regulates the stability of Tec1 protein which controls the chronological life span of yeast cells. The detection of TCS elements in NTH1 promotor region enhances the probability of NTH1 gene regulation by Tec1. In order to determine the effect of Tec1 transcription factor on NTH1 gene expression, Nth1-LacZ gene fusion plasmid was transformed to wild type and Δtec1 mutant S. cerevisiae yeast cells. The amount of NTH1 gene expression and trehalose accumulation were determined in the presence of good and poor nitrogen sources both in wild type and mutant yeast cells. The results showed that in the absence of Tec1 protein NTH1 gene was activated and trehalose accumulation decreased considerably at normal growth conditions. These results revealed that, Tec1 transcription factor is essential for negative regulation of NTH1 transcription, especially under abundance of nutrient.

Anahtar Kelimeler

NTH1, Tec1p, trehalose, Saccharomyces cerevisiae

Tec1 Transkripsiyon Faktörünün NTH1 Gen Ekspresyonuna Etkisi

Öz

Hücre
içi trehaloz birikimi maya hücrelerinin farklı çevresel streslere karşı
oluşturduğu fizyolojik cevaplardan birisidir. Saccharomyces cerevisiae maya hücrelerinde trehaloz miktarı hücre
döngüsünün farklı aşamalarında farklı miktarlarda bulunmakta olup kronolojik
yaşam uzunluğunu etkilemektedir. Stres koşullarında biriktirilen trehalozun
yıkımından sorumlu nötral trehalaz enzimini kodlayan NTH1 geninin ekspresyonu farklı sinyal yolakları üzerinden kontrol
edilmektedir. Bu yolaklardan bir tanesi TOR sinyal yolağı olup aynı zamanda bu
yolak maya hücrelerinin kronolojik yaşam uzunluğunu etkileyen Tec1
transkripsiyon faktörünün de stabilitesini etkilemektedir. Trehaloz sentezinden
ve yıkımından sorumlu genlerin promotor bölgelerinin analizinde NTH1 promotorundan tespit edilen TCS
elementleri Tec1 proteinin NTH1
geninin regülasyonunda görev alma olsılığını kuvvetlendirmektedir. Tec1
transkripsiyon faktörünün NTH1 gen
ekspresyonuna etkisini belirlemek amacıyla, yaban tip ve ∆tec1 S. cerevisiae maya
hücrelerine NTH1 promotor bölgesi ve LacZ gen füzyonu içeren
plazmit aktarılmıştır. Kuvvetli azot ve zayıf azot kaynaklarında, Tec1
proteinin varlığında ve yokluğunda maya hücrelerinin trahaloz birikimleri ve NTH1 gen ekspresyon miktarları enzimatik
olarak belirlenmiştir. Tec1 proteininin yokluğunda NTH1 geninin aktive olduğu ve trehaloz birikiminin oldukça azaldığı belirlenmiştir. Elde edilen
sonuçlar Tec1 transkripsiyon faktörünün özellikle normal
üreme koşullarında NTH1
transkripsiyonunun negatif düzenlenmesi için gerekli olduğunu göstermiştir.

Anahtar Kelimeler

NTH1, Tec1p, trehaloz, Saccharomyces cerevisiae

Kaynakça

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