Abstract: We provide reporter gene constructs incorporating nucleic acid sequences from a promoter region of a gene or set of genes whose expression is modified in response to external or internal changes in the cellular environment such as biochemical stress or toxic conditions. The promoters are operatively linked to nucleic acid sequences chosen on the basis of the ease with which their transcription and/or translation products may be assayed so that the reporter gene constructs can provide a system capable of detecting intracellular conditions. Also described are transfected cell lines including the constructs and transgenic non-human animal models including the constructs.