Glucose Signaling Pathway and Growth Conditions Regulate Gene Expression in Retrotransposon Ty2

Abstract

Gene expression in the yeast retrotransposon Ty2 is regulated at transcriptional and translational levels. In this study, we have shown that the transcription of Ty2 is partially dependent on the membrane-bound glucose sensors Gpr1p and Mth1p in Saccharomyces cerevisiae. Transcription of Ty2 decreased approx. 3-fold in the gpr1, mth1 yeast mutant. Moreover, our results revealed that the transcription of Ty2 fluctuates during the growth stages of S. cerevisae. Both transcription and the frameshift rate of Ty2 rapidly dropped when the stationary stage yeast cells were inoculated into fresh medium. There was an instant activation of Ty2 transcription and a high level expression during the entire logarithmic stage of yeast growth. However, the transcription of Ty2 decreased 2-fold when the yeast cultures entered the stationary stage. The frameshift rate in Ty2 also varied depending on the growth conditions. The highest frameshift level was observed during the mid-logarithmic stage. It decreased up to 2-fold during the stationary stage. Furthermore, we have found that the frameshift rate of Ty2 diminished at least 5-fold in slowly growing yeasts. These results indicate that the transcription and the frameshift efficiency are coordinately regulated in the retrotransposon Ty2 depending on the growth conditions of S. cerevisiae.

Ribosomal frameshifting and transcriptional slippage: From genetic steganography and cryptography to adventitious use

“…luteovirus), and animal (cardioviruses and HIV), viral frameshifting on viral life cycle stage or cell status is described above. Frameshifting to synthesize S. cerevisiae Ty1 and/or its close relative Ty2, GagPol changes in a growth-stage dependent manner (624,625). Cell cycle stage relevance of EST3 and antizyme frameshifting is also described above.…”

“…Ty1 frameshifting decreases 4-fold in glycerol-lactate grown cells compared to cells grown in media with the preferred carbon and energy source, glucose (625), and glucose level effects with bacterial IS1 have also been reported (623). Ty3 frameshifting efficiency varies up to 10-fold depending on the carbon source, but in contrast to Ty2, it is lower in glucose grown cells than in poorer carbon-source media (625). Previously it was shown that Ty3 Pol and transposition decreases dramatically with high temperature or growth in ethanol (626) where the frameshifting rate is greatly reduced (216).…”

Amino Acid Starvation Enhances Programmed Ribosomal Frameshift in Metavirus Ty3 ofSaccharomyces cerevisiae

“…cAMP dependent protein kinase-A is also involved in the regulation of frameshift efficiency in Ty3 [9]. In addition, we have analyzed the effects of glucose signaling on the PRF efficiency in Ty1 elements and shown that the Ty1 type +1 PRF frequency decreases several fold in glycerol-lactate-grown S. cerevisiae cells [8]. Atkins and Björk [10] have also reported that mutations in certain ribosomal proteins and tRNAs also affect the PRF rate in both bacteria and yeast.…”

“…The rate of PRF shows variations among retroviruses and retroviral-like elements [6]. The PRF rate is approximately 4-5% in Ty3, while it is 25% in Ty1 under standard growth conditions in most of the laboratory strains of S. cerevisiae (in synthetic complete medium supplemented with 2% glucose in logarithmically grown cells at 30 ∘ C) [8,9].…”

Glucose signalling pathway controls the programmed ribosomal frameshift efficiency in retroviral‐like element Ty3 in Saccharomyces cerevisiae

“…() also reported that the PRF frequency changes in Ty1 in a growth stage‐dependent manner in yeast; the growth stage effect may also function through frameshift‐regulating signalling pathways. In addition, we reported that the Ty1 type +1 PRF frequency decreases several fold in gycerol–lactate‐grown S. cerevisiae cells (Türkel et al ., ); this carbon source regulation may function through one or more signalling pathways.…”