Dynamics of activation of a galactose-inducible promoter in Saccharomyces cerevisiae.
We have investigated the dynamics of accumulation of the Escherichia coli beta-galactosidase (beta-gal) under the control of a promoter containing the galactose-inducible upstream activating sequence (UASG) in single Saccharomyces cerevisiae cells. The accumulation of beta-gal in single cells following the addition of the inducer, galactose, was determined using an in situ combined DNA and immunofluorescent stain in conjunction with flow cytometry. Two strains were studied, D603/2i, which has two copies of the galactose-inducible fusion gene integrated into its genome, and D603/pLGSD5, which carries a 2 microns-based plasmid containing the fusion gene. Flow cytometry results indicate that accumulation of beta-gal within the first three hours following the addition of galactose is dependent on cell cycle position. Two proposed mechanisms explaining this observed behavior are (1) the cell-cycle-dependent synthesis of the fusion protein or (2) the unequal partitioning of the protein at cell division between mother and daughter cells.
Institute of Advanced Studies in Biological Process Technology and Materials Science, University of Minnesota, St. Paul 55108.
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D002453:Cell Cycle; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D001616:beta-Galactosidase / Q000096:biosynthesis*
D004247:DNA; D001616:beta-Galactosidase