A SET OF VECTORS WITH A TETRACYCLINE-REGULATABLE PROMOTER SYSTEM FOR MODULATED GENE-EXPRESSION IN SACCHAROMYCES-CEREVISIAE

A set of Saccharomyces cerevisiae expression vectors has been develope d in which transcription is driven by a hybrid tetO-CYC1 promoter thro ugh the action of a tetR-VP16 (tTA) activator. Expression from the pro moter is regulated by tetracycline or derivatives. Various modalities of promoter and activator are used in order to achieve different level s of maximal expression. In the presence of antibiotic in the growth m edium at concentrations that do not affect cell growth, expression fro m the tetO promoter is negligible, and upon antibiotic removal inducti on ratios of up to 1000-fold are observed with a lacZ reporter system. With the strongest system, overexpression levels comparable with thos e observed with GAL1-driven promoters are reached. For each particular promoter/tTA combination, expression can be modulated by changing the tetracycline concentration in the growth medium. These vectors may be useful for the study of the function of essential genes in yeast, as well as for phenotypic analysis of genes in overexpression conditions, without restrictions imposed by growth medium composition. (C) 1997 b y John Wiley & Sons, Ltd.