The Levels of Yeast Gluconeogenic mRNAs Respond to Environmental Factors

Authors

  • Juan J. Mercado,

    1. Instituto de Investigaciones Biomédicas del Consejo Superior de Investigaciones Cientificas, Facultad de Medicina, Universidad Autónoma de Madrid, Spain
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  • Rachel Smith,

    1. Department of Molecular and Cell Biology, University of Aberdeen, Scotland
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  • Francis A. Sagliocco,

    1. Department of Molecular and Cell Biology, University of Aberdeen, Scotland
    2. Laboratoire de Génétique, Unité Associée Centre National de la Recherche Scientifique 542, Université de Bordeaux, France
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  • Alistair J. P. Brown,

    1. Department of Molecular and Cell Biology, University of Aberdeen, Scotland
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  • Juana M. Gancedo

    Corresponding author
    1. Instituto de Investigaciones Biomédicas del Consejo Superior de Investigaciones Cientificas, Facultad de Medicina, Universidad Autónoma de Madrid, Spain
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J. M. Gancedo, Instituto de Investigaciones Biomédicas del Consejo Superior de Investigaciones Cientificas, Facultad de Medicina, Universidad Autónoma de Madrid, Arturo Duperier 4, E-28029 Madrid, Spain

Abstract

The FBP1 and PCK1 genes encode the gluconeogenic enzymes fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase, respectively. In the yeast, Saccharomyces cerevisiae, the corresponding mRNAs are present at low levels during growth on glucose, but are present at elevated levels during growth on gluconeogenic carbon sources. We demonstrate that the levels of the FBP1 and PCK1 mRNAs are acutely sensitive to the addition of glucose to the medium and that the levels of these mRNAs decrease rapidly when glucose is added to the medium at a concentration of only 0.005%. At this concentration, glucose blocks FBP1 and PCK1 transcription, but has no effect on iso-1 cytochrome c (CYCI) mRNA levels. Glucose also increases the rate of degradation of the PCK1 mRNA approximately twofold, but only has a slight effect upon FBP1 mRNA turnover. We show that the levels of the FBP1 and PCK1 mRNAs are also sensitive to other environmental factors. The levels of these mRNAs decrease transiently in response to a decrease of the pH from pH 7.5 to pH 6.5 in the medium, or to a mild temperature shock (from 24°C to 36°C). The latter response appears to be mediated by accelerated mRNA decay.

Abbreviations
ACT1

actin gene

CYC1

iso-1 cytochrome c gene

FBP1

fructose-1,6-bisphosphatase gene

PCK1

phosphoenolpyruvate carboxykinase gene

Enzymes
 

Fructose-1,6-bisphosphatase (EC 3.1.3.11)

 

phosphoenolpyruvate carboxykinase (4.1.1.49)

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