Janus kinase 1 is essential for inflammatory cytokine signaling and mammary gland remodeling

Jak1 is a ubiquitously expressed tyrosine kinase that transduces extracellular signals from a variety of cytokines and their receptors to downstream signal transducers and activators of transcription (STATs). Since deficiency in Jak1 causes early neonatal lethality, we generated Jak1 conditional knockout mice to study the biological role of this kinase during the development of the mammary gland in adult females Total RNA was extracted from flash-frosen mammary gland tissues of seven conditional knockout females(3 lactation, 4 second day of involution) and six wildtype control mice(3 lactating, 3 involution)