They were then caged individually with a male mouse, and the presence of a vaginal plug the following morning confirmed successful mating (Day 1 of pregnancy).
Particularly interesting is the action of regulatory proteins that trigger the activation of transcription factors termed STATs (Signal Transducer and Activator of Transcription).
The STAT proteins, of which seven have been described so far, are phosphorylated by Janus kinases (Jak), which are activated by cytokine receptors; phosphorylated STATs form dimers, enter the nucleus, and regulate gene transcription .
Preimplantation mouse embryos simultaneously express receptors for leptin and leukemia inhibitory factor (LIF), both of which trigger activation of STAT3 (Signal Transducer and Activator of Transcription) protein.
To examine the joint effects of leptin and LIF on embryonic development, we studied preimplantation development and activation of STAT3 signaling of mouse embryos after exposure to leptin and/or LIF in vitro.
Fallopian tubes were dissected and flushed with M2 medium (Sigma-Aldrich Norway AS, Oslo, Norway).