Vectors with the gus reporter gene for identifying and quantitating promoter regions in Saccharomyces cerevisiae

The Escherichia coli β-glucuronidase-encoding gene gusA is useful as a reporter gene in a variety of organisms. In this report, we describe the development of two related vectors, pGUS1 and pGUS2, which can be used to identify and quantitate activities of the promoter regions from yeast genes. Both vectors contain several unique restriction sites upstream from gus and the yeast CYC1 transcription terminator downstream from gus. In addition, pGUS2 carries the yeast ADH1 transcriptional terminator sequence upstream from gus, in order to block read-through transcription originating in vector sequences. Both vectors were tested after cloning the well-characterized GAL1,10 promoter region from yeast. These GAL1,10-containing plasmids demonstrated appropriate regulation of the reporter in response to carbon sources. The pGUS1 and pGUS2 vectors provide a simple, reliable and extremely sensitive reporter-gene system that allows quantitative measurement of promoter activity of yeast DNA sequences. Furthermore, the presence of a terminator sequence upstream from gus in pGUS2 should facilitate analysis and quantitation of expression from weak promoters.