Metabolic control of gene expression: in vivo studies with transgenic mice.

Transgenic animals provide a comprehensive model for investigating genes encoding inducible enzymes involved in metabolism, since the molecular mechanisms regulating gene transcription can be studied in the whole animal. Studies on the promoters of the genes encoding two key enzymes in the gluconeogenic and glycolytic pathways--phosphoenol-pyruvate carboxykinase and pyruvate kinase are described as examples of this approach. Work on the phosphoenolpyruvate carboxykinase promoter using transgenic mice has been particularly informative: the cis-acting elements involved in hormonal regulation, tissue specificity and developmental inhibition of gene expression have been identified and their function in vivo examined.