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Toxicity mechanisms of the food contaminant citrinin: application of a quantitative yeast model.

Pascual-Ahuir A, Vanacloig-Pedros E, Proft M - Nutrients (2014)

Bottom Line: Additionally, genes in various multidrug resistance transport systems are functionally involved in the resistance to citrinin.Our study identifies the antioxidant defense as a major physiological response in the case of citrinin.In general, our results show that the use of live cell gene expression reporters in yeast are a powerful tool to identify toxicity targets and detoxification mechanisms of a broad range of food contaminants relevant for human nutrition.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain. apascual@ibmcp.upv.es.

ABSTRACT
Mycotoxins are important food contaminants and a serious threat for human nutrition. However, in many cases the mechanisms of toxicity for this diverse group of metabolites are poorly understood. Here we apply live cell gene expression reporters in yeast as a quantitative model to unravel the cellular defense mechanisms in response to the mycotoxin citrinin. We find that citrinin triggers a fast and dose dependent activation of stress responsive promoters such as GRE2 or SOD2. More specifically, oxidative stress responsive pathways via the transcription factors Yap1 and Skn7 are critically implied in the response to citrinin. Additionally, genes in various multidrug resistance transport systems are functionally involved in the resistance to citrinin. Our study identifies the antioxidant defense as a major physiological response in the case of citrinin. In general, our results show that the use of live cell gene expression reporters in yeast are a powerful tool to identify toxicity targets and detoxification mechanisms of a broad range of food contaminants relevant for human nutrition.

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Related in: MedlinePlus

Citrinin activates gene expression via the oxidative stress responsive transcription factors Yap1 and Skn7. A fusion of the stress inducible GRE2 promoter with destabilized luciferase was used as a real time reporter for gene expression. The reporter activity was measured in yeast wild type and yap1 or skn7 mutants upon addition of the indicated concentrations of citrinin. Data shown are mean values from three independent biological samples. SD < 15%.
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nutrients-06-02077-f003: Citrinin activates gene expression via the oxidative stress responsive transcription factors Yap1 and Skn7. A fusion of the stress inducible GRE2 promoter with destabilized luciferase was used as a real time reporter for gene expression. The reporter activity was measured in yeast wild type and yap1 or skn7 mutants upon addition of the indicated concentrations of citrinin. Data shown are mean values from three independent biological samples. SD < 15%.

Mentions: To further investigate the relation between citrinin toxicity and oxidative stress signaling, we monitored the toxin induced gene expression in yeast strains which lacked the activity of the two main transcriptional activators operating upon oxidative stress: Yap1 and Skn7. We used the GRE2-luciferase reporter system to compare the immediate transcriptional upregulation upon citrinin exposure in wild type compared to yap1 or skn7 knockout mutants. As shown in Figure 3, in the absence of Yap1 the citrinin induced reporter activity was severely reduced. Yap1 might therefore be one of the main transcriptional regulators which is activated in response to citrinin stress. Skn7 seemed to be additionally involved in the citrinin response; however, its contribution was clearly less important as compared to Yap1 (Figure 3).


Toxicity mechanisms of the food contaminant citrinin: application of a quantitative yeast model.

Pascual-Ahuir A, Vanacloig-Pedros E, Proft M - Nutrients (2014)

Citrinin activates gene expression via the oxidative stress responsive transcription factors Yap1 and Skn7. A fusion of the stress inducible GRE2 promoter with destabilized luciferase was used as a real time reporter for gene expression. The reporter activity was measured in yeast wild type and yap1 or skn7 mutants upon addition of the indicated concentrations of citrinin. Data shown are mean values from three independent biological samples. SD < 15%.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4042565&req=5

nutrients-06-02077-f003: Citrinin activates gene expression via the oxidative stress responsive transcription factors Yap1 and Skn7. A fusion of the stress inducible GRE2 promoter with destabilized luciferase was used as a real time reporter for gene expression. The reporter activity was measured in yeast wild type and yap1 or skn7 mutants upon addition of the indicated concentrations of citrinin. Data shown are mean values from three independent biological samples. SD < 15%.
Mentions: To further investigate the relation between citrinin toxicity and oxidative stress signaling, we monitored the toxin induced gene expression in yeast strains which lacked the activity of the two main transcriptional activators operating upon oxidative stress: Yap1 and Skn7. We used the GRE2-luciferase reporter system to compare the immediate transcriptional upregulation upon citrinin exposure in wild type compared to yap1 or skn7 knockout mutants. As shown in Figure 3, in the absence of Yap1 the citrinin induced reporter activity was severely reduced. Yap1 might therefore be one of the main transcriptional regulators which is activated in response to citrinin stress. Skn7 seemed to be additionally involved in the citrinin response; however, its contribution was clearly less important as compared to Yap1 (Figure 3).

Bottom Line: Additionally, genes in various multidrug resistance transport systems are functionally involved in the resistance to citrinin.Our study identifies the antioxidant defense as a major physiological response in the case of citrinin.In general, our results show that the use of live cell gene expression reporters in yeast are a powerful tool to identify toxicity targets and detoxification mechanisms of a broad range of food contaminants relevant for human nutrition.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain. apascual@ibmcp.upv.es.

ABSTRACT
Mycotoxins are important food contaminants and a serious threat for human nutrition. However, in many cases the mechanisms of toxicity for this diverse group of metabolites are poorly understood. Here we apply live cell gene expression reporters in yeast as a quantitative model to unravel the cellular defense mechanisms in response to the mycotoxin citrinin. We find that citrinin triggers a fast and dose dependent activation of stress responsive promoters such as GRE2 or SOD2. More specifically, oxidative stress responsive pathways via the transcription factors Yap1 and Skn7 are critically implied in the response to citrinin. Additionally, genes in various multidrug resistance transport systems are functionally involved in the resistance to citrinin. Our study identifies the antioxidant defense as a major physiological response in the case of citrinin. In general, our results show that the use of live cell gene expression reporters in yeast are a powerful tool to identify toxicity targets and detoxification mechanisms of a broad range of food contaminants relevant for human nutrition.

Show MeSH
Related in: MedlinePlus