Project description:Transcriptional profiling of yeast transcription factor deletion strains (rox1, xbp1 or phd1) and wild-type strains in response to hydrogen peroxide or butanol
Project description:In S. cerevisiae, the forkhead transcription factor Hcm1 has been involved in chromosome segregation, spindle pole dynamics and budding. We found that, in response to oxidative stress stimuli, Hcm1 shifts from cytoplasm to the nucleus, interacting with the histone deacetylase Sir2, which regulates Hcm1 localization. Hcm1-overexpressing cells showed increased resistance to oxidative stress which can be attributed to increased catalase and Sod2 activities. Microarray analysis revealed that genes corresponding to mitochondrial function and transition from exponential to stationary phase are clearly induced in these cells which consistently showed higher rates of oxygen consumption due to an increase in mitochondria – possibly triggered by higher amounts of Abf2, a protein involved in mitochondrial biogenesis. In wild-type cells, when glucose levels decreased by 50%, we observed Hcm1 translocation to the nucleus and increased Hcm1 levels. We conclude that Hcm1 may act as an early regulator to respond to nutrient limitation, increasing stress resistance and mitochondrial function and thereby allowing the cells to adapt to nutrient limitations by shifting from fermentative to respiratory metabolism.
