การแสดงออกของยีน MSN4 และยีนภายใต้การควบคุมในยีสต์ Saccharomyces cerevisiae สายพันธุ์ทนร้อน Expression of MSN4 and Genes under Its Regulation in Thermotolerant Saccharomyces Cerevisiae

Msn2p and its homolog Msn4p in yeast Saccharomyces cerevisiae are transcription factors which regulate the genes in response to general stresses including heat to protect cell damage. They bind specifically to stress-response elements (STREs) and activate the transcription of its target genes. In this work, we have focused on the role of Msn4p in heat stress of natural thermotolerant yeast strain. Based on DNA microarray data of S. cerevisiae, we searched for genes that are regulated by Msn4p under high temperature growth by computational analysis using YEASTRACT. Among 303 up-regulated genes (≥2-folds), 56 genes contained STREs at their upstream promoter. Investigation of yeast disruptants in those 56 genes revealed that 17 disruptants showed high temperature sensitive growth phenotype. By real-time PCR analysis, the change in expression level along growth phase at high temperature of MSN4 was not observed whereas expression of UBI4 significantly increased in both natural thermotolerant and laboratory strains. In addition, the expression level of NTH1, known as Msn4p-regulated gene, also elevated. These observations suggest that higher expression of UBI4 at early-log phase could support the heat resistance phenotype in both of laboratory and thermotolerant strains.