title: Human p53 induces cell death and downregulates thioredoxin expression in Saccharomyces cerevisiae.
abstract: The p53 tumour suppressor protein has a crucial role in controlling cell cycle and apoptosis in human cells and its inactivation by selective point mutations is associated with human cancers. Here we show that overexpression of the human wild-type (wt) p53 in Saccharomyces cerevisiae completely inhibits yeast growth under minimal media conditions. In contrast, the R248W 'hot spot' p53 mutant (one of the most frequent p53 mutations encountered in human cancers) does not impair yeast growth. Moreover, we report, for the first time, that the human wt p53 induces yeast cell death with characteristic markers of apoptosis: exposure of phosphatidylserine and DNA strand cleavage as shown by Annexin V staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay, respectively. In addition, p53 also has an impact on the expression of yeast genes. Using differential display and Northern blot analysis, we demonstrated that human wt p53 expression in yeast leads to gene repression of thioredoxin (TRX1/2), a highly conserved multifunctional antioxidative and antiapoptotic protein family. Accordingly, we demonstrated that reactive oxygen species (ROS) are highly produced in p53 yeast induced cell death as shown by dihydrorhodamine 123 staining. These results suggest that the generation of ROS is a key event in p53 yeast induced cell death.
authors.affiliation: Laboratoire de Génétique Moléculaire des Eucaryotes, Centre de Biotechnologie de Sfax, Sfax, Tunisia.
authors.forename: Ines Yacoubi
authors.initials: IY
authors.lastname: Hadj Amor
authors.forename: Kamel
authors.initials: K
authors.lastname: Smaoui
authors.forename: Ines
authors.initials: I
authors.lastname: Chaabène
authors.forename: Imed
authors.initials: I
authors.lastname: Mabrouk
authors.forename: Lamia
authors.initials: L
authors.lastname: Djemal
authors.forename: Henda
authors.initials: H
authors.lastname: Elleuch
authors.forename: Michèle
authors.initials: M
authors.lastname: Allouche
authors.forename: Raja
authors.initials: R
authors.lastname: Mokdad-Gargouri
authors.forename: Ali
authors.initials: A
authors.lastname: Gargouri
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D003470:Culture Media; D015536:Down-Regulation / Q000187:drug effects*; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D013879:Thioredoxins