Figure 2. Lack of LIF prevents activation of STAT3 signaling. Relative levels of Lif, Clc, Stat3, and Socs3 mRNAs (as indicated) were analyzed by real-time PCR in retinas of Lif^+/– and Lif^–/– mice before (controls) or at 12 h after exposure to 15,000 lx of white light for 2 h. RNA levels were expressed relative to levels in Lif^+/– controls, which were set to 1. β-actin served as reference. Shown are means±SD of n=3.