Project description:The S. cerevisiae genome is the most well-characterized eukaryotic genome and one of the simplest in terms of identifying open reading frames (ORFs), yet its primary annotation has been updated continually in the decade since its initial release in 1996 (Goffeau et al., 1996). The Saccharomyces Genome Database (SGD; www.yeastgenome.org) (Hirschman et al., 2006), the community-designated repository for this reference genome, strives to ensure that the S. cerevisiae annotation is as accurate and useful as possible. At SGD, the S. cerevisiae genome sequence and annotation are treated as a working hypothesis, which must be repeatedly tested and refined. In this paper, in celebration of the tenth anniversary of the completion of the S. cerevisiae genome sequence, we discuss the ways in which the S. cerevisiae sequence and annotation have changed, consider the multiple sources of experimental and comparative data on which these changes are based, and describe our methods for evaluating, incorporating and documenting these new data.
Project description:The diploid isolate EM93 is the main ancestor to the widely used Saccharomyces cerevisiae haploid laboratory strain, S288C. In this study, we generate a high-resolution overview of the genetic differences between EM93 and S288C. We show that EM93 is heterozygous for >45,000 polymorphisms, including large sequence polymorphisms, such as deletions and a Saccharomyces paradoxus introgression. We also find that many large sequence polymorphisms (LSPs) are associated with Ty-elements and sub-telomeric regions. We identified 2,965 genetic markers, which we then used to genotype 120 EM93 tetrads. In addition to deducing the structures of all EM93 chromosomes, we estimate that the average EM93 meiosis produces 144 detectable recombination events, consisting of 87 crossover and 31 non-crossover gene conversion events. Of the 50 polymorphisms showing the highest levels of non-crossover gene conversions, only three deviated from parity, all of which were near heterozygous LSPs. We find that non-telomeric heterozygous LSPs significantly reduce meiotic recombination in adjacent intervals, while sub-telomeric LSPs have no discernable effect on recombination. We identified 203 recombination hotspots, relatively few of which are hot for both non-crossover gene conversions and crossovers. Strikingly, we find that recombination hotspots show limited conservation. Some novel hotspots are found adjacent to heterozygous LSPs that eliminate other hotspots, suggesting that hotspots may appear and disappear relatively rapidly.
Project description:A systematic approach allowing the identification of the molecular way-of-action of novel potential drugs represents the golden-tool for drug-discovery. While high-throughput screening technologies of large libraries is now well established, the assessment of the drug targets and mechanism of action is still under development. Taking advantage of the yeast model Saccharomyces cerevisiae, we herein applied BarSeq, a Next Generation Sequencing-based method to the analysis of both haploinsufficiency and homozygous fitness effects of a novel antifungal drug ('089') compared to the well-known antifungal ketoconazole. '089' was a novel compound identified in during a screen for antifungal drugs, as it was showing fungicidal effects, and able to affect the yeast fitness at the mitochondrial level (Stefanini et al., 2010. (Dissection of the Effects of Small Bicyclic Peptidomimetics on a Panel of Saccharomyces cerevisiae Mutants;.J Biol Chem, 285: 23477-23485.) Integrative bioinformatic analysis of BarSeq, whole genome expression analysis and classical biological assays identified the target and cell pathways affected by the novel antifungal. Confirmation of the effects observed in the yeast model and in pathogenic fungi further demonstrated the reliability of the multi-sided approach and the novelty of the targets and way-of-action of the new class of molecules studied representing a valuable source of novel antifungals.
Project description:Yeast homozygous and essential heterozygous deletion mutants were screened against 3,250 diverse growth inhibitory compounds, resulting in a chemogenomic profile for each compound. A profile permits the identification of putative protein targets via drug-induced haploinsufficiency, and provides a genome-wide description of the cellular response to the profiled compound. Therefore, our aims were to identify putative protein inhibitors and in general, to improve understanding of the cellular response to small molecules.