FIG. 5.

Rex1 promoter RFP have a stress dose-dependent loss of endogenous Rex1 protein corresponding to dose-dependent loss of Rex1 activity shown in Fig. 3. (A) Rex1-RFP mESCs were cultured until 30% confluent, treated with 0, 200–300 mM sorbitol in 25 mM increments for 3 days (as in Fig. 3), lysed, size fractionated by SDS-PAGE, blotted, probed for Rex1 and ACTB proteins, and analyzed for changes compared to time zero and stress dose responses. The histogram bars are derived from three independent experiments, one of which is shown in (A), shown are X ± SEM, n = 3, (a) is P < 0.05 and (b) indicates not significant. (B) One-way ANOVA was performed followed by Dunnett's post hoc test; (a) indicates significantly lower endogenous Rex1 at 225–300 mM sorbitol (P < 0.05), but not at 200 mM sorbitol (b).