(A) Induction of Rac1 mRNA in the uterus during experimentally-induced decidualization. Uterine RNA was purified from mice at different times after decidual stimulation and analyzed by qPCR. Relative levels of Rac1 mRNA expression in uteri after decidual stimulation are compared to those in unstimulated control uteri. Data represent mean ± SEM from three separate samples and were analyzed by one-way ANOVA with Bonferroni post-test. Letters indicate statistically significant differences (P < 0.0001). (B) Expression of Rac1 during early pregnancy overlaps with the decidual phase of gestation. qPCR was performed to monitor the expression of Rac1 mRNA in uteri on days 1 to 8 of gestation. The relative levels of gene expression on different days of pregnancy were determined by setting the expression level of Rac1 mRNA on day 1 of pregnancy at 1.0. Rplp0, encoding a ribosomal protein, was used to normalize the level of RNA. Data represent mean ± SEM from three separate samples and were analyzed by one-way ANOVA with Bonferroni post-test. Letters indicate statistically significant differences (P < 0.0001). (C) Localization of active RAC1 protein in uterine stromal cells during early pregnancy. Uterine sections on day 7 of pregnancy were subjected to immunofluorescence (IF) histochemistry using anti-RAC1-GTP antibody. Panels a, b, and c show immunostaining of RAC1-GTP; panels d, e, and f show staining with non-immune IgG. AMD, MD and E indicate antimesometrial decidua, mesometrial decidua and embryo, respectively.