Project description:Ribosome profiling (Ribo-Seq) and RNA-Seq analysis of eEF3 depletion in yeast (Saccharomyces cerevisiae). eEF3 depletion was induced by methionine in a modified strain where the native promoter was replaced by methionine repressible MET25 promoter. Conditional depletion enables us to study global effects of an essential gene.
Project description:The canonical role of eEF1A is to deliver the aminoacyl tRNA to the ribosome, we have used the yeast model system to investigate further roles for this protein. We used microarray to study the transcriptomic effects of elevated levels of eEF1A on yeast cells during log phase growth Overall design: Yeast cells were grown to log phase, the RNA extracted and hybridised to affymetrix arrays.
Project description:To investigate the glucose regulatory system in Saccharomyces cerevisiae, we conducted a time-course in which glucose-depleted wildtype (WT) cells were inoculated into fresh media (SC, 2% glucose). Their subsequent transcriptional output was monitored over a period of five hours by DNA microarrays: samples for gene expression profiling were taken immediately after, as well as 3, 7.5, 15, 30, 60, 110, 150, and 300 minutes after inoculation into fresh medium. Transcripts upregulated are involved in translational processes such as the GO biological processes “ribosome biogenesis” and “ribosome localization”. Transcripts downregulated are enriched for the GO biological processes “cellular respiration” and various metabolism related processes. The time-course was used to verify the physiological relevance of gene expression profiles determined for individual deletions of glucose regulatory system components. Importantly, transcripts up- or downregulated in WT cells upon the addition of glucose are similarly up- or downregulated in deletion mutants that each lack a component of the glucose regulatory system. RNA isolated from a large amount of wt yeast from a single culture was used as a common reference. This common reference was used for each separate hybridization and used in the statistical analysis to obtain an average expression-profile for each deletion mutant relative to the wt. Two independent cultures were hybridized on two separate microarrays. For the first hybridization the Cy5 (red) labeled cRNA from the deletion mutant is hybridized together with the Cy3 (green) labeled cRNA from the common reference. For the replicate hybridization, the labels are swapped. Each gene is represented twice on the microarray, resulting in four measurements per mutant. Two overnight WT cultures were used to inoculate 50 ml cultures at an OD600 of 0.15. These were depleted of glucose by growing for 24 hours and were used the next day to inoculate 500 ml cultures in fresh medium to an OD600 of 0.15. Samples for expression profiling were taken immediately after, as well as 3, 7.5, 15, 30, 60, 110, 150, and 300 minutes after inoculation into fresh medium.
Project description:Abf1 and Reb1, two general regulatory factors playing roles at promoters and other genome functional sites in budding yeast, were mapped genome-wide by ChIP-sequencing using strains expressing TAP-tagged versions of the proteins. As expected on the basis of previous in silico analysis of promoter regions, we found that these factors are enriched at the promoters of ribosome biogenesis (Ribi) genes, a large regulon of more than 200 genes required for ribosome biosynthesis and assembly, and known to be coordinately regulated in response to nutrient availability and cellular growth rate. Overall design: The reported analysis was designed as a confirmative experiment. Chromatin immunoprecipitation of TAP-tagged Abf1 and Reb1 was carried out using logarithmically growing yeast cells, as described in Fermi et al (2016) Nucleic Acids Res, March 25, doi:10.1093/nar/gkw194