A study on the use of strain-specific and homologous promoters for heterologous expression in industrial Saccharomyces cerevisiae strains.

Polymorphism is well known in Saccharomyces cerevisiae strains used for different industrial applications, however little is known about its effects on promoter efficiency. In order to test this, five different promoters derived from an industrial and a laboratory (S288c) strain were used to drive the expression of eGFP reporter gene in both cells. The ADH1 promoter (P ADH1 ) in particular, which showed more polymorphism among the promoters analyzed, also exhibited the highest differences in intracellular fluorescence production. This was further confirmed by Northern blot analysis. The same behavior was also observed when the gene coding for secreted α-amylase from Cryptococcus flavus was placed under the control of either P ADH1 . These results underline the importance of the careful choice of the source of the promoter to be used in industrial yeast strains for heterologous expression.