Genome-Wide expression under osmotic stress conditions in Saccharomyces cerevisiae

Changes in RNA levels during osmotic stress were investigated. Total RNA was extracted from a wild-type yeast strain before and after treatment with 0.4 M NaCl and the corresponding cDNAs were hybridazed on Tiling arrays. In particular, for all the intron-containing genes, the changes in the levels of intron signal in stressed cells related to the intron signal in the non-stressed cells, and the changes in the levels of exon signal in stresses cells related to the exon signal in non-stressed cells were investigated. The supplementary bar file contains the ratios between stress signals respect to non-stress signals, using the average of the 3 biological replicas. For the tiling array experiments, total RNA was extracted from exponentially YPD growing W303-1A cells before and after treatment for 15 min with 0.4M NaCl. The hybridization of tiling array Affymetrix (GeneChip® S. cerevisiae Tiling 1.0R Array) with cDNA produced from total RNA, was carried out according to the Affymetrix protocol and using GeneChip® Hybridization, Wash and Stain Kit (P/N 900720). The final data were obtained from the results of three independent biological experiments. High-density tiling arrays images were normalised and analysed using the Affymetrix Tiling Analysis Software; and were visualized by the Integrated Genome Browser (Affymetrix).