Isolation and Characterization of Salt Street Signaling Components from Yeast Saccharomyces cerevisiae

To identify novel components involved in the salt stress signaling pathway of yeast cells, we used mTn3-mediated transposon tagging library and screened mutants displaying enhanced tolerance to NaCl. Southern blot analysis indicated that more than 80% of the sre (salt resistant) mutants possessed only one insertion of the tagged transposon, suggesting that the NaCl resistant phenotype was mediated by a single gene in the majority of the mutants. To define the role of SRE genes in the salt stress signaling pathway, we introduced NaCl stress-inducible ENA1::LacZ construct into the sre mutants and examined the expression of ${\beta}$-galactosidase activity. Interestingly, we could detect high level of ${\beta}$-galactosidase activity without any NaCl treatment in the sre-3, 4, 6 and 7 mutants. These results indicate that SRE-3, 4, and 7 gene are components of salt stress signaling pathway of yeast cells.