Molecular analysis of the MSN2 gene of Saccharomyces cerevisiae

MAZA D.D.; MIRANDA LEIVA L.F.; VIÑARTA S.C.; AYBAR M.J.

S.M. de TUCUMÁN

Congreso; THIRD JOINT MEETING OF THE BIOLOGY SOCIETIES OF ARGENTINA; 2015

TheMSN2 gene encodes a transcription factor involved in the regulation of a gene setinduced as adaptive responses to adverse culture conditions such as carbonsource starvation, heat shock and severe osmotic and oxidative stresses.In this study, we cloned MSN2 and studied its expression in response todifferent osmotic stress conditions using a reference strain of S. cerevisiae. In this work we analyzedthe MSN2 sequence in different organisms by the use of bioinformatic tools and studiedthe effect of osmotic stress generated by KCl and NaCl on the growth of S. cerevisiae ATCC 32051. In theseculture conditions we evaluated the expression levels of MSN2 bysemiquantitative RT-PCR. We identified putative MSN2 orthologs in other fungalspecies and found high similarity regions that could guide the homology cloningapproach for other species of interest. Osmotic stress affected the normalgrowth of S. cerevisiae showingbetter tolerance to KCl than to NaCl. As the concentration of NaCl or KCl inthe medium increased, the generation time raised and a delay on the phases ofgrowth was observed. High concentrations of NaCl and KCl (>1.5 M) were toxicto S. cerevisiae. The highestexpression level of MSN2 was achieved at 0.5 M NaCl and the expression levelsare maintained high until 12 hours of culture. These results suggest that MSN2has a key role in osmotic stress response and its expression is necessary forlong periods of time to maintain the adaptation to adverse culture conditions.