title: Induced gene expression in industrial Saccharomyces pastorianus var. carlsbergensis TUM 34/70: evaluation of temperature and ethanol inducible native promoters.
abstract: Induced gene expression is an important trait in yeast metabolic engineering, but current regulations prevent the use of conventional expression systems, such as galactose and copper, in food and beverage fermentations. This article examines the suitability of temperature-inducible native promoters for use in the industrial yeast strain Saccharomyces pastorianus var. carlsbergensis TUM 34/70 under brewing conditions. Ten different promoters were cloned and characterized under varying temperature shifts and ethanol concentrations using a green fluorescent protein reporter. The activities of these promoters varied depending upon the stress conditions applied. A temperature shift to 4°C led to the highest fold changes of PSSA3, PUBI4 and PHSP104 by 5.4, 4.5 and 5.0, respectively. Ethanol shock at 24°C showed marked, concentration-dependent induction of the promoters. Here, PHSP104 showed its highest induction at ethanol concentrations between 4% (v/v) and 6% (v/v). The highest fold changes of PSSA3 and PUBI4 were found at 10% (v/v) ethanol. In comparison, the ethanol shock at a typical fermentation temperature (12°C) leads to lower induction patterns of these promoters. Taken together, the data show that three promoters (PHSP104, PUBI4 and PSSA3) have high potential for targeted gene expression in self-cloning brewing yeast using temperature shifts.
authors.affiliation: Chair of Brewing and Beverage Technology, Technische Universität München, Weihenstephaner Steig 20, D-85354 Freising, Germany susann.fischer@tum.de.
authors.forename: S
authors.initials: S
authors.lastname: Fischer
authors.affiliation: Chair of Brewing and Beverage Technology, Technische Universität München, Weihenstephaner Steig 20, D-85354 Freising, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Engstler
authors.affiliation: Chair of Brewing and Beverage Technology, Technische Universität München, Weihenstephaner Steig 20, D-85354 Freising, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Procopio
authors.affiliation: Chair of Brewing and Beverage Technology, Technische Universität München, Weihenstephaner Steig 20, D-85354 Freising, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Becker
mesh_terms: D019677:Artificial Gene Fusion; D003001:Cloning, Molecular; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D015870:Gene Expression / Q000187:drug effects* / Q000528:radiation effects*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects* / Q000528:radiation effects*; D012440:Saccharomyces / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D013696:Temperature; D015533:Transcriptional Activation / Q000187:drug effects / Q000528:radiation effects
chemical_list: D049452:Green Fluorescent Proteins; D000431:Ethanol
keywords: enhanced green fluorescence protein; induced gene expression; lager yeast; promoter strength; temperature shift