Tracking the activation of Stat5 through the expression of an inducible reporter gene in a transgenic mouse line.

Signal transducer and activator of transcription 5 (Stat5), a latent cytoplasmic transcription factor, becomes activated by phosphorylation upon cytokine, hormone, and growth factor interactions with their appropriate receptors and induces the transcription of target genes. It plays crucial roles in principal cell fate decisions and regulates cell differentiation, development, proliferation, apoptosis, and inflammation. It is active in the mammary gland, the liver, hematopoietic cells, and other organs and has pleiotropic functions, depending on its activation pathway and its site of action.

Visualization of Stat3 and Stat5 transactivation activity with specific response element dependent reporter constructs integrated into lentiviral gene transfer vectors.

Background: Signal transducer and activator of transcription 3 and 5 (Stat3 and Stat5) play important roles in cell differentiation, proliferation, apoptosis and inflammation. They are transiently activated by ligand-receptor interactions in normal cells but are often found to be constitutively active in cancer cells. Analysis of their activation pattern is therefore important for the description of developmental processes and the understanding of cellular transformation.