Project description:The effect of Sfp1 depeltion at transcriptional level was investigated by construting a AID-Sfp1 strain (Auxin sensitive degron) that allowed to shutoff the Sfp1 expression and analyze the primary effects on synthesis rates (SR) and mRNA levels (RA) genome-wide. mRNA stabilities can be calculated as RA /SR for each gene in all samples.
Project description:We set out to determine how Sfp1 binding targets evolved over time. We sampled our species of interest to include one pre-whole genome duplicaton (WGD) species containing SFP1A (K. lactis), one post-WGD species containing both SFP1 and SFP1PL (N. castellii), two post-WGD species containing only SFP1 (S. cerevisiae and S. paradoxus) and performed ChIP for each Sfp1 homolog in each species using an antibody that recognizes a conserved subdomain of Sfp1 common to both Sfp1, Sfp1a, and Sfp1pl. Because Sfp1pl was also present in N. castellii, a second antibody was used that is more specific to Sfp1pl (denoted as IP3). We also performed ChIP in SFP1 deletion mutants in each species tested, as a control."
Project description:In Saccharomyces cerevisiae growth, size control and cell cycle progression are strictly coordinated and regulated according to the nutritional conditions. In particular, ribosome biogenesis appears a key event in this regulatory network. SFP1 encodes a zinc-finger protein promoting the transcription of a large cluster of genes involved in ribosome biogenesis. It has been suggested that Sfp1 is a cell size modulator acting at Start. To better study the regulatory role of Sfp1 and its putative involvement in cell size and cycle control, we analysed the behaviour of an sfp1 null mutant strain and of an isogenic reference strain growing in chemostat cultures. This approach allowed us to analyze both strains at the same specific growth rate, thus eliminating the secondary effects due to the slow growing phenotype that the sfp1 null mutant shows in shake flask. We studied glucose(anaerobic)- and ethanol(aerobic)-limited cultures, as paradigms of two different metabolic states. Major alterations of the transcriptional profile were observed during growth on glucose, while no significant differences were observed when comparing ethanol growing cultures. In particular, in the former growth condition, Sfp1 appears involved in the control of ribosome biogenesis but not of ribosomal protein gene expression. Keywords: global transcriptional profile, genetic modification, ribosome biogenesis
Project description:We measured global expression profiles in SFP1 deletion mutants and isogenic wild type strains during lag and log phase growth. To match the physiology of each species as well as minimize the effect on gene expression from differences in early growth rates, we profiled expression during log growth and lag after glucose repletion as previously described (Thompson et al., 2013).
Project description:In Saccharomyces cerevisiae growth, size control and cell cycle progression are strictly coordinated and regulated according to the nutritional conditions. In particular, ribosome biogenesis appears a key event in this regulatory network. SFP1 encodes a zinc-finger protein promoting the transcription of a large cluster of genes involved in ribosome biogenesis. It has been suggested that Sfp1 is a cell size modulator acting at Start. To better study the regulatory role of Sfp1 and its putative involvement in cell size and cycle control, we analysed the behaviour of an sfp1 null mutant strain and of an isogenic reference strain growing in chemostat cultures. This approach allowed us to analyze both strains at the same specific growth rate, thus eliminating the secondary effects due to the slow growing phenotype that the sfp1 null mutant shows in shake flask. We studied glucose(anaerobic)- and ethanol(aerobic)-limited cultures, as paradigms of two different metabolic states. Major alterations of the transcriptional profile were observed during growth on glucose, while no significant differences were observed when comparing ethanol growing cultures. In particular, in the former growth condition, Sfp1 appears involved in the control of ribosome biogenesis but not of ribosomal protein gene expression. Experiment Overall Design: The reference S. cerevisiae strain CEN.PK113.7D and the isogenic sfp1 null mutant were grown in chemostat cultures under ethanol(aerobic)- and glucose(anaerobic)- limitation. The dilution rate was set at 0.10 h-1 and 0.05 h-1 for ethanol- and glucose-limited cultures, respectively. A genome-wide transcriptional analysis was performed for the reference and the sfp1 null mutant strains for each growth condition. All data presented in this work were derived from three independent chemostat cultures (12 samples in total were analysed).
Project description:Understanding how transcriptional programs help to coordinate cell growth and division is an important unresolved problem. Here we report that the nutrient- and stress-regulated transcription factor Sfp1 is rate-limiting for expression of a large suite of genes involved in yeast cell growth, including ribosomal protein, ribosome biogenesis, and snoRNA genes. Remarkably, the spectrum of Sfp1 transcription effects is concordant with a combination of chromatin immunoprecipitation and chromatin endogenous cleavage binding analyses, which together provide evidence for two distinct modes of Sfp1 promoter binding, one requiring a co-factor and the other a specific DNA-recognition motif. In addition to growth-related genes, Sfp1 binds to and regulates the promoters of key G1/S regulon genes and that of MRS6, whose product regulates Sfp1 nuclear localization. Our findings suggest that Sfp1 acts as a master regulator of cell growth and cell size by coordinating the expression of genes implicated in mass accumulation and cell division.
Project description:To investigate the roles of Sfp1, we used a whole-genome DNA microarray to compare gene expression patterns between the sfp1-deleted and wild-type strains. Among the upregulated genes, a subset of genes is involved in oxidative stress response, including CAP1, SSK1, and SHO1. The CAP1 gene product is a bZip transcription factor involving in regulation of antioxidant gene expression. The SSK1 and SHO1 gene encodes a response regulator of two-component system and an adaptor protein in the Hog1 MAPK signaling pathway, respectively. Moreover, the sfp1-deleted mutant also exhibited an upregulation of genes encoding various antioxidants and enzymes controlling the cellular redox state, especially components of the glutathione system. Noticeably, 8 of the 21 upregulated glutathione-related genes (GCS1, GTT11, YCF1, CYS3, CIP1, EBP1, IFD6, and OYE32) are controlled by Cap1. This result raises a possibility that Sfp1 is involved in C. albicans oxidative stress response and somehow coordinately regulates these glutathione-related genes with Cap1.