REGULATION BY LOW-TEMPERATURES AND ANAEROBIOSIS OF A YEAST GENE SPECIFYING A PUTATIVE GPI-ANCHORED PLASMA-MEMBRANE

Expression of the yeast Saccharomyces cerevisiae SRP1 (Serine-rich pro tein) gene is shown here to be induced both by low temperature and ana erobic growth conditions. We show that anaerobic SRP1 expression is ha em-dependent; however, haem influence does not operate through the act ion of the hypoxic-gene ROX1 repressor. The SRP1 promoter region displ aying the stress-responsive elements is restricted to its first 551 bp , upstream of the initiation codon, although an upstream activation si te contained in upstream sequences is required for full promoter activ ity. In addition, we demonstrate that the TIP1 gene, sharing similar n ucleotide and polypeptide structure with SRP1, and previously reported to be a cold-shock-inducible gene, is also a hypoxic gene. Srp1 prote in production is similarly induced by low temperature and anaerobic gr owth conditions. This protein, detected in the plasma membrane fractio n, is shown to be exposed on the cell surface via a glycosylphosphatid ylinositol membrane anchoring.