Figure 4. Deletion of Chop in Cx50D47A homozygotes does not affect activation of endoplasmic reticulum (ER) stress transduction pathways. A: Immunoblots of immunoreactive phosphorylated (top panel) and total (middle panel) eukaryotic translation initiation factor‐2A (P-EIF2α and EIF2α, respectively) in total lens homogenates from 1-month-old homozygous Cx50D47A mice that were wild type for Chop or heterozygous or homozygous Chop knockout. The migration positions of the molecular mass markers are indicated on the left. The graph in the bottom panel shows the ratios of phosphorylated to total EIF2α (P-EIF2α/EIF2α) calculated from the densitometric values of the immunoreactive bands obtained from three independent biological replicates as the mean (bar) + standard error of the mean (SEM). B: Graph showing the ratio of spliced (sXbp-1) to total (tXbp-1) Xbp-1 in lenses from 1-month-old homozygous Cx50D47A mouse littermates that were wild type for Chop (Chop^+/+) or heterozygous (Chop^+/−) or homozygous (Chop^−/−) Chop knockout as determined by real-time quantitative PCR in three independent biological replicates. Data are presented as the mean (bar) + SEM.