An engineered yeast as a potential biosensor of environmental stress

We developed a simple quantitative assay to detect stress activated nuclear translocation of nucleo-cytoplasmic protein in the yeast S. cerevisiae. The assay relies on the fusion of a transcription factor comprising the bacterial DNA binding domain (bDBD) and the activation domain of the yeast (yAD) to YAP1 and the β-galactosidase gene placed under the promoter inducible by bDBD-yAD transcription factor. YAPI (yeast) is known to shuttle between the nucleus and the cytoplasm during oxidative stress. After stress, bDBD-yAD-YAP1 chimeric proteins localization can be simply quantified by measuring β-galactosidase expression. We analysed H2O and mercury response. Very low mercury (down to 5 10-7 M) and H2O2 (5 10-5 M) concentrations activated the YAP1 translocation system. This quick and easy to use assay, based on yeast engineered for detection and quantization of translocation factor, may represent a suitable bio indicator to quantified environmental heavy metal exposure. (Author) 4 refs