Project description:High concenHigh concentration acetic acid in the fermentation medium represses cell growth, metabolism and fermentation efficiency of Saccharomyces cerevisiae, which is widely used for cellulosic ethanol production. Our previous study proved that supplementation of zinc sulfate in the fermentation medium improved cell growth and ethanol fermentation performance of S. cerevisiae under acetic acid stress condition. However, the molecular mechanisms is still unclear. To explore the underlying mechanism of zinc sulfate protection against acetic acid stress, transcriptomic and proteomic analysis were performed. The changed genes and proteins are related to carbon metabolism, amino acid biosynthesis, energy metabolism, vitamin biosynthesis and stress responses. In a total, 28 genes showed same expression in transcriptomic and proteomic data, indicating that zinc sulfate affects gene expression at posttranscriptional and posttranslational levels.tration acetic acid in the fermentation medium represses cell growth, metabolism and fermentation efficiency of Saccharomyces cerevisiae, which is widely used for cellulosic ethanol production. Our previous study proved that supplementation of zinc sulfate in the fermentation medium improved cell growth and ethanol fermentation performance of S. cerevisiae under acetic acid stress condition. However, the molecular mechanisms is still unclear. To explore the underlying mechanism of zinc sulfate protection against acetic acid stress, transcriptomic and proteomic analysis were performed. The changed genes and proteins are related to carbon metabolism, amino acid biosynthesis, energy metabolism, vitamin biosynthesis and stress responses. In a total, 28 genes showed same expression in transcriptomic and proteomic data, indicating that zinc sulfate affects gene expression at posttranscriptional and posttranslational levels.
Project description:Invasive fungal infections (IFIs) are difficult to treat. Few effective antifungal drugs are available and many have problems with toxicity, efficacy and drug-resistance. To overcome these challenges, existing therapies may be enhanced using more than one agent acting in synergy. Previously, we have found amphotericin B (AMB) and the iron chelator, lactoferrin (LF), were synergistic against Cryptococcus neoformans and Saccharomyces cerevisiae. This study investigates the mechanism of AMB+LF synergy, using RNA-seq and network analyses. Genes involved in iron homeostasis showed increased expression upon treatment with AMB alone. Unexpectedly, AMB+LF treatment did not lead to increased expression of iron or zinc homeostasis genes however we observed decreased expression of oxidative stress response genes. Addition of iron or zinc to AMB+LF treated cells did not rescue the synergy, supporting the likelihood that the mechanism of synergy involves more than iron and zinc chelation. We clustered genes based on patterns of co-expression and found by network analysis that many genes involved in iron and zinc homeostasis, which have dysregulated expression upon AMB+LF treatment, are targets of transcription factors Aft1p and Zap1p. Hypothesizing that these might play a key role in the synergistic response, knock-out mutants of Aft1 and Zap1 were tested for increased sensitivity to AMB and oxidative stress. Both mutants showed hypersensitivity towards these treatments. Our results suggest the mechanism of AMB+LF synergy involves disruption to oxidative stress response, in addition to chelation of iron and zinc. Since Zap1 is conserved in C. neoformans and contains a putative drug binding domain, we suggest novel Zap1 binding molecules could be combined with existing antifungals to serve as synergistic antifungal treatments for this species.
Project description:Aneuploidy and aging are correlated; however, a causal link between these two phenomena has remained elusive. Here we show that yeast disomic for a single native yeast chromosome generally have a decreased replicative lifespan. In addition, the extent of this lifespan deficit correlates with the size of the extra chromosome. We identified a mutation in BUL1 that rescues both the lifespan deficit and a protein trafficking defect in yeast disomic for chromosome 5. Bul1 is an E4 ubiquitin ligase adaptor involved in a protein quality-control pathway that targets membrane proteins for endocytosis and destruction in the lysosomal vacuole thereby maintaining protein homeostasis. Concurrent suppression of the aging and trafficking phenotypes suggests that disrupted membrane protein homeostasis in aneuploid yeast may contribute to their accelerated aging. The data reported here demonstrate that aneuploidy can impair protein homeostasis, shorten lifespan, and may contribute to age-associated phenotypes.
Project description:Transcriptional profiling of Saccharomyces cerevisiae cells comparing the W303-1A wildtype with the W303-1A double mutant for MSN2 and MSN4 during zinc deficient conditions Keywords: Genetic modification with zinc limitation
Project description:Ribosome specialization is an emerging concept which challenges the common assumption that translation relies on a standardized molecular machinery. In this work, we demonstrate that Tma108, a yeast uncharacterized translation machinery-associated factor, defines a subpopulation of the cellular ribosomes specifically involved in the translation of less than 200 mRNAs encoding proteins with ATP or zinc binding domains. Ribonucleoparticle dissociation experiments support the fact that Tma108 directly interacts with the nascent protein chain. Comparative genomic analyses and molecular modeling point out Tma108 as an original M1 metallopeptidase with specific residues in the catalytic pocket which may explain its selectivity. The involvement of Tma108 in co-translational regulations is attested by the drastic perturbation of the subcellular localization of ATP2 mRNA, one of its targets, upon TMA108 inactivation. Tma108 is an unique example of a nascent chain-associated factor with high selectivity and illustrates the existence of specific translation-associated factors, besides RNA binding proteins.