The Function Of Yf1052wp, A Zinc Cluster Protein Transcription Factor In Saccharomyces Cerevisiae

Temperature fluctuating is an important environmental stress to yeast in nature and industrial application (such as ethanol fermentation). Normally, the optimum temperature of yeast cell ranges from25to30℃, but severe heat stress (or heat shock) will lead to various physiological disorders in yeast cells, such as protein folding mistake and accumulation, the damage of protein, lipid and DNA resulting from oxidative stress induced by ROS production because of the disorder of electron transmission system, the disorder of cell wall constructure and function, even cell death. Uncovering the mechanisms underlying the thermostabality of Saccharomyces cerevisiae is greatly meaningful for clarifying environmental adaption mechanism of eukaryotic organism and for construction of industrial application strains with excellent performance.In this work, through array-comparative genomic hybridization (aCGH) of two industrial S.cerevisiae stains YJS329and ZK2with different high temperature tolerance, we found that the difference of genomic structure is an important reason of phenotype difference and that the transcription factor YFL052W (located at the left of chromosome6) was lost in the genome of ZK2. The introduction of YFL052W into ZK2improved its tolerance to various environmental stresses, including high temprature tolerance. This result suggested that YFL052W is involved in variety of stress tolerance of yeast. Moreover, overexpression of YFL052W enhanced the ethanol production of YJS329and ZK2by2.5and3.8%under high-gravity conditions, respectively. This genetic manipulation improved the viabilities of the engineered strain ZK2YFL052W at the end of ethanol fermentation. To understand the function of YFL052W, we further investigate the expression regulation and physiological function in laboratory strain BY4741. RT-qPCR and Western blot analysis showed that the expression level of the transcription factor Yf1052wp was affected by growth phase state and stress factors such as heat shock, acetic acid and ethanol. Then, RNA-Seq was performed in strains BY4741and BY4741△YFL052W, and-115genes with different expression levels between the two strains were identified. Gene function annotation showed that some genes related with cell wall function (such as SRL1, GAS1, SCWU, DSE2) are down-regulated when YFL052W was deleted. In addition, the lost of these genes reduced the tolerance to heat shock of yeast. Finally, Msn2/4p, Hsflp and Stb5p TF binding sites were predicted in the promoter of YFL052W using software. These results suggested that YFL052W may play a role of heat shock response by regulating the expression of genes related with cell wall and YFL052W itself was regulated by other heat shock response factors or other similar transcription factors.