Phase-specific gene expression in Saccharomyces cerevisiae, using maltose as carbon source under oxygen-limiting conditions.

The transcription of ten stress-response genes was investigated under oxygen-limiting conditions with maltose and glucose, respectively. Six of these genes (HSP12, HSP26, HSP30, HSP78, HSP82 and HSP104) showed expression only during the stationary phase. HSP12 and HSP104 were transcribed 10 h earlier with maltose than with glucose. Fermentation in wort yielded similar results to the maltose-based medium. HSP12, HSP26 and HSP30 were highly expressed. Thus, the HSP26 and the HSP30 promoter can be used for late, phase-specific expression of the desired genes with glucose or maltose as carbon source, and HSP12 with glucose only. MET14, a gene important for sulfite formation, was overexpressed in wort, using the HSP26 promoter during the stationary phase.