Role of Yap4 in Yeast Osmotic Stress Response

The role of the S. cerevisiae Yap4 transcription factor in the response to hyperosmolarity was investigated in two ways. Firstly, to assess the overall response of the yap4 deleted strain genome wide analysis upon a mild upshift in osmolarity was compared to the same response in the wt strain. Secondly, in order to identify genes whose osmo-expression is differentially regulated in the mutant strain (ie potential Yap4 target genes) the relative abundance of cDNAs of the wt and yap4 mutant strain obtained upon an osmotic upshift were directly compared by microarray analysis. Keywords: Mutant Stress Response Expt 1: The response of the wt to mild hyperosmolarity (0.4M NaCl) Serving as the exptal control, this experiment identifies the response of the wt strain to 0.4M NaCl. cDNAs obtained from total RNA extracted from wt cells subjected (test) or not (reference) to the indicated conditions for 10 minutes were labeled with Cy3 (reference) or Cy5 (test). Expt 2: Identification of potential Yap4 target genes under mild hyperosmolarity (0.4M NaCl). cDNAs obtained from total RNA extracted from wt (reference) and yap4 mutant (test) cells subjected to 0.4M NaCl for 10 minutes were labeled with Cy3 (reference) or Cy5 (test). Expt 3: The response of the yap4 mutant to mild hyperosmolarity (0.4M NaCl). cDNAs obtained from total RNA extracted from the yap4 mutant subjected (test) or not (reference) to 0.4M NaCl for 10 minutes were labeled with Cy3 (reference) or Cy5 (test).