Transcription profiling of Saccharomyces cerevisiae genomic DNA, nucleosomal DNA and the yeast strain to analyse diversity of eukaryotic DNA replication origins revealed by genome-wide analysis of chromatin structure
ABSTRACT: Genomic DNA from Saccharomyces cerevisiae W303-1A was isolated along with nucleosomal DNA from W303-1A and the yeast strain GAL:orc2-1. Nucleosomal DNA was isolated following a 2h release from a nocodazole block in which the medium was changed from galactose (YPAG) to glucose (YPAD).
Project description:Cells respond to stress and starvation by adjusting their growth rate and enacting stress defense programs. In eukaryotes this involves inactivation of TORC1, which in turn triggers downregulation of ribosome and protein synthesis genes and upregulation of stress response genes. Here we report that the highly conserved inositol pyrophosphate second messengers (including 1-PP-IP5, 5-PP-IP4, and 5-PP-IP5) are also critical regulators of cell growth and the general stress response, acting in parallel to the TORC1 pathway to control the activity of the class I HDAC Rpd3L. In fact, yeast cells that cannot synthesize any of the PP-IPs mount little to no transcriptional response in osmotic, heat, or oxidative stress. Furthermore, PP-IP dependent regulation of Rpd3L occurs independently of the role individual PP-IPs (such as 5-PP-IP5) play in activating specialized stress/starvation response pathways. Thus, the PP-IP second messengers simultaneously activate and tune the global response to stress and starvation signals. 2-condition experiments. Includes the responses of wild-type (ACY 044) and mutant yeast strains (all are W303 background) to log growth and stress conditions. This series of microarrays were performed on null mutants of various genes in the inositol pyrophosphate synthesis pathway, including several members of the Rpd3L histone deacetylase complex. All mutants were made in W303 strain, MatA yeast, using standard techniques (homologous recombination). Several stress conditions were tested, including heat-shock, oxidative (H2O2), and osmotic stress (0.375M KCl). Cells in mid-log growth were subjected to stress for 20 minutes. In one instance the TOR inhibitor rapamycin was added to determine whether PP-IPs act above/at or below TORC1 in activating the ESR. Taken together, these microarrays show the role of the inositol pyrophosphate synthesis pathway in activating the ESR in stress.
Project description:Cisplatin is commonly used in cancer therapy and yeast cells are also sensitive to this compound. We present a transcriptome analysis discriminating between RNA changes induced by cisplatin treatment, which are dependent on or independent of SKY1 function--a gene whose deletion increases resistance to the drug. Gene expression changes produced by addition of cisplatin to W303 and W303-?sky1 cells were recorded using DNA microarrays. The data, validated by quantitative PCR, revealed 122 differentially expressed genes: 69 upregulated and 53 downregulated. Among the upregulated genes, those related to sulfur metabolism were over-represented and partially dependent on Sky1. Deletions of MET4 or other genes encoding co-regulators of the expression of sulfur-metabolism-related genes, with the exception of MET28, did not modify the cisplatin sensitivity of yeast cells. One of the genes with the highest cisplatin-induced upregulation was SEO1, encoding a putative permease of sulfur compounds. We also measured the platinum, sulfur and glutathione content in W303, W303-?sky1 and W303-?seo1 cells after cisplatin treatment, and integration of the data suggested that these transcriptional changes might represent a cellular response that allowed chelation of cisplatin with sulfur-containing amino acids and also helped DNA repair by stimulating purine biosynthesis. The transcription pattern of stimulation of sulfur-containing amino acids and purine synthesis decreased, or even disappeared, in the W303-?sky1 strain.
Project description:Seven temperature sensitive Saccharomyces cerevisiae BY4741 mutants (rsc3-1, abf1-101, reb1-212, rap1-1, mcm1, tbf1 and cep3-1) were grown at restrictive temperatures until a difference in OD600 was observed relative to a wild-type control. Nucleosomal DNA, whole genomic DNA and total RNA were isolated and hybridized onto yeast whole-genome tiling arrays.<br>
Project description:The yeast Saccharomyces cerevisiae has emerged as a superior model organism. Selection of distinct laboratory strains of S. cerevisiae with unique phenotypic properties, such as superior mating or sporulation efficiencies, has facilitated advancements in research. W303 is one such laboratory strain that is closely related to the first completely sequenced yeast strain, S288C. In this work, we provide a high-quality, annotated genome sequence for W303 for utilization in comparative analyses and genome-wide studies. Approximately 9500 variations exist between S288C and W303, affecting the protein sequences of ∼700 genes. A listing of the polymorphisms and divergent genes is provided for researchers interested in identifying the genetic basis for phenotypic differences between W303 and S288C. Several divergent functional gene families were identified, including flocculation and sporulation genes, likely representing selection for desirable laboratory phenotypes. Interestingly, remnants of ancestor wine strains were found on several chromosomes. Finally, as a test of the utility of the high-quality reference genome, variant mapping revealed more accurate identification of accumulated mutations in passaged mismatch repair-defective strains.
Project description:DCP (2-4-dichlorophenol; 0,3mM) and POELE (polyoxyethylen-9-laurylether; 0,1mM)treatment on Saccharomyces cerevisiae W303-1A wild-type cells. Further investigation of the involvement of the transcripton factors Pdr1 and Pdr3 in DCP treated cells. Cells were growing in early exponential phase in rich medium.
Project description:Saccharomyces cerevisiae strain W303 is a widely used model organism. However, little is known about its genetic origins, as it was created in the 1970s from crossing yeast strains of uncertain genealogy. To obtain insights into its ancestry and physiology, we sequenced the genome of its variant W303-K6001, a yeast model of ageing research. The combination of two next-generation sequencing (NGS) technologies (Illumina and Roche/454 sequencing) yielded an 11.8 Mb genome assembly at an N50 contig length of 262 kb. Although sequencing was substantially more precise and sensitive than whole-genome tiling arrays, both NGS platforms produced a number of false positives. At a 378× average coverage, only 74 per cent of called differences to the S288c reference genome were confirmed by both techniques. The consensus W303-K6001 genome differs in 8133 positions from S288c, predicting altered amino acid sequence in 799 proteins, including factors of ageing and stress resistance. The W303-K6001 (85.4%) genome is virtually identical (less than equal to 0.5 variations per kb) to S288c, and thus originates in the same ancestor. Non-S288c regions distribute unequally over the genome, with chromosome XVI the most (99.6%) and chromosome XI the least (54.5%) S288c-like. Several of these clusters are shared with Σ1278B, another widely used S288c-related model, indicating that these strains share a second ancestor. Thus, the W303-K6001 genome pictures details of complex genetic relationships between the model strains that date back to the early days of experimental yeast genetics. Moreover, this study underlines the necessity of combining multiple NGS and genome-assembling techniques for achieving accurate variant calling in genomic studies.
Project description:All yeast strains were in the genetic background W303-1A (MATa leu2-3,112 trp1-1 ura3-1 can1-100 ade2-1 his3-11,15). Gene expression profiles of the following mutant strains were compared with WT: YIA29 (mdl1::HIS3); YIA30 (yme1::KAN); YIA31 (mdl1::HIS3 yme1::KAN); 2 independent RNA preparations per strain were used (A and B); 2 independent array hybridisations per RNA preparation were performed (color switch experiments).
Project description:Different cell types can form patterns within fungal communities; for example, colonies of Saccharomyces cerevisiae form two sharply defined layers of sporulating cells separated by an intervening layer of unsporulated cells. Because colony sporulation patterns have only been investigated in a single laboratory strain background (W303), in this report we examined these patterns in other strain backgrounds. Two other laboratory strain backgrounds (SK1 and Sigma1278b) that differ from W303 with respect to colony morphology, invasive growth, and sporulation efficiency nevertheless displayed the same colony sporulation pattern as W303. This pattern was also observed in colonies of wild isolates of S. cerevisiae and Saccharomyces paradoxus. The wild yeast colonies sporulated on a much wider range of carbon sources than did the lab yeast and displayed a similar layered sporulation pattern when grown on either acetate or glucose medium and on either rich or synthetic medium. SK1, Sigma1278b and wild yeast colonies invaded the agar surface. The region of invasion varied between strains with respect to the organization and appearance of cells, but this invasion was always accompanied by sporulation. Thus, sporulation patterns are a general property of S. cerevisiae, and sporulation in colonies can be coordinated with invasive growth.