Timing and Variability of Galactose Metabolic Gene Activation Depend on the Rate of Environmental Change.
PLoS Comput Biol
; 11(7): e1004399, 2015 Jul.
Article
en En
| MEDLINE
| ID: mdl-26200924
ABSTRACT
Modulation of gene network activity allows cells to respond to changes in environmental conditions. For example, the galactose utilization network in Saccharomyces cerevisiae is activated by the presence of galactose but repressed by glucose. If both sugars are present, the yeast will first metabolize glucose, depleting it from the extracellular environment. Upon depletion of glucose, the genes encoding galactose metabolic proteins will activate. Here, we show that the rate at which glucose levels are depleted determines the timing and variability of galactose gene activation. Paradoxically, we find that Gal1p, an enzyme needed for galactose metabolism, accumulates more quickly if glucose is depleted slowly rather than taken away quickly. Furthermore, the variability of induction times in individual cells depends non-monotonically on the rate of glucose depletion and exhibits a minimum at intermediate depletion rates. Our mathematical modeling suggests that the dynamics of the metabolic transition from glucose to galactose are responsible for the variability in galactose gene activation. These findings demonstrate that environmental dynamics can determine the phenotypic outcome at both the single-cell and population levels.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
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Ecosistema
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Reactores Biológicos
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Proteínas de Saccharomyces cerevisiae
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Galactosa
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Glucosa
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
PLoS Comput Biol
Asunto de la revista:
BIOLOGIA
/
INFORMATICA MEDICA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Estados Unidos